DE102017112656B4 - System and method for regulating engine knock - Google Patents

Abstract

A method of operating an engine, comprising:
Judging whether knock is present in a cylinder that combusts air and fuel by receiving an input to a controller;
Adjusting, via the controller, a rate of spark advance applied to the cylinder after judging that knock is present in the cylinder in response to a means by which the cylinder was previously deactivated.

Description

Area

The present description relates to systems and methods for regulating knock of an internal combustion engine. The systems and methods may be applied to engines that include engine cylinder deactivation.

Background and brief description

An engine may include a knock control system to reduce engine knock. The knock system may retard the ignition timing of a cylinder exhibiting knock to reduce the possibility of engine wear. The ignition timing for the cylinder may subsequently be advanced as knocking is suppressed to increase engine efficiency. The ignition advance rate is a constant value. Advancing the ignition timing after retarding the ignition timing may result in further engine knock indications if the ignition advance rate is too high. On the other hand, if the ignition advance rate is too low, the engine's fuel efficiency may deteriorate. Therefore, it may be desirable to provide a way to adjust the ignition advance rate that improves engine efficiency but does not result in engine knock in a short period of time.

The writing US 2016 / 0 146 127 A1 discloses systems and methods for controlling the spark advance of an engine. One method allows the engine to be operated with a pre-delivery calibration prior to delivery, which is deactivated after delivery.

The writing US 2014 / 0 278 010 A1 discloses systems and methods for detecting engine knock. Indicators are generated based on the current engine operating conditions. A module for detecting engine noise is also used.

The present invention solves the problem of increasing the efficiency of an internal combustion engine and reducing the possibility of engine wear by regulating the occurrence of engine knocking.

The problem is solved by the features of the independent patent claims. Advantageous developments of the invention are described in the subclaims.

The inventors of the present invention have recognized the above-mentioned disadvantages and developed a method of operating an engine, comprising: judging whether knocking is present in a cylinder that combusts air and fuel by receiving an input to a controller; adjusting, via a controller, a rate of ignition advance supplied to the cylinder after judging that knocking is present in the cylinder in response to a possibility that the cylinder was previously deactivated.

By adjusting a rate of spark advance delivered to a cylinder after it has been judged that knock is present in the cylinder, in response to a way in which a cylinder was previously deactivated, it may be possible to provide the technical result of improving engine fuel efficiency while reducing engine knock. For example, the engine cylinders may be deactivated by terminating fuel flow to the cylinders while continuing to operate the cylinder's intake and exhaust valves, or by other methods described herein. Airflow through the cylinders quickly cools the cylinder. If a driver quickly increases a torque request and knock occurs as a result, spark timing may be retarded to regulate knock. However, the spark advance rate may be set to a higher level because the cylinder has cooled and it is expected that knock may return more slowly. Conversely, if the engine cylinders have been deactivated by stopping the fuel flow to the cylinders and closing the intake and exhaust valves for an engine cycle, the engine cylinders cannot cool down very quickly because the flow through the cylinders is restricted. If a driver rapidly increases a torque demand and knock occurs under these circumstances, the ignition timing can also be retarded to regulate knock. However, the ignition advance rate can be set to a lower level because the cylinder has not cooled down as much as if the cylinders were deactivated with working valves. Consequently, knock can be expected to return more quickly. By reducing the ignition advance rate, the possibility that the Engine knock returning after ignition has been retarded in response to a previous knock event.

The present description may provide several advantages. For example, the approach may improve the fuel efficiency of the vehicle. Additionally, the approach may reduce the possibility of engine knock recurring after a knock event. Furthermore, the approach may improve the vehicle's drivability.

The foregoing advantages, as well as other advantages and features of the present description, will be readily apparent from the following detailed description when read alone or in conjunction with the accompanying drawings.

It should be understood that the foregoing Summary is provided to introduce, in a simplified manner, a selection of concepts that are further described in the Detailed Description. It is not intended to identify important or pertinent features of the claimed subject matter, the scope of which is defined solely in the claims following the Detailed Description. Furthermore, the claimed subject matter is not limited to implementations that overcome disadvantages noted above or in any part of this disclosure.

Brief description of the drawings

• 1A eine schematische Darstellung eines einzelnen Zylinders eines Motors ist;
• 1B eine schematische Darstellung des Motors nach 1A ist, der in einen Antriebsstrang integriert ist;
• 2A-2F beispielhafte Ventilauslegungen für Vierzylindermotoren mit Zylindern zeigen, die abgeschaltet werden können;
• 3A und 3B beispielhafte Muster angeschalteter und abgeschalteter Zylinder eines Vierzylindermotors zeigen;
• 4A-4C beispielhafte Ventilauslegungen für einen Achtzylindermotor mit Zylindern zeigen, die abgeschaltet werden können;
• 5A beispielhafte Nockenwellen für ein hydraulisch betriebenes Ventilabschaltungssystem zeigt;
• 5B beispielhafte Abschaltungsventilantriebe für das hydraulisch betriebene Ventilabschaltungssystem zeigt, das in 5A gezeigt wird;
• 5C einen beispielhaften Ventilantrieb für das hydraulisch betriebene Ventilabschaltungssystem zeigt, das in 5A gezeigt wird;
• 5D eine beispielhafte Zylinder- und Ventilabschaltungssequenz für das hydraulisch betriebene Ventilabschaltungssystem zeigt, das in 5A gezeigt wird;
• 6A eine beispielhafte Nockenwelle für ein alternatives hydraulisch betriebenes Ventilabschaltungssystem zeigt;
• 6B einen Querschnitt einer Nockenwelle und eines Sockels für das hydraulisch betriebene Ventilabschaltungssystem zeigt, das in 6A gezeigt wird;
• 6C beispielhafte Ventil-Abschaltungsventilantriebe für das hydraulisch betriebene Ventilabschaltungssystem zeigt, das in 6A gezeigt wird;
• 6D eine beispielhafte Zylinder- und Ventilabschaltungssequenz für das hydraulisch betriebene Ventilabschaltungssystem ist, das in 6A gezeigt wird;
• 7 ein Ablaufdiagramm eines Beispielverfahrens zum Betreiben eines Motors mit einem Abschalten von Zylindern und Ventilen ist;
• 8A ein Ablaufdiagramm eines beispielhaften Verfahrens zum selektiven Anschalten und Abschalten von Zylindern und Zylinderventilen eines Motors ist, mit sowohl Abschaltungs- als auch Nichtabschaltungseinlassventilen und nur mit Nichtabschaltungsauslassventilen;
• 8B ein Blockdiagramm zum Schätzen einer Ölmenge in einem abgeschalteten Zylinder ist;
• 9 eine beispielhafte Sequenz zum Anschalten und Abschalten von Zylindern und Zylinderventilen eines Motors ist, mit sowohl Abschaltungs- als auch Nichtabschaltungseinlassventilen und nur mit Nichtabschaltungsauslassventilen;
• 10 ein Ablaufdiagramm eines beispielhaften Verfahrens zum selektiven Anschalten und Abschalten von Zylindern und Zylinderventilen eines Motors ist, mit sowohl Abschaltungs- als auch Nichtabschaltungseinlassventilen und mit Nichtabschaltungs- und Abschaltungsauslassventilen;
• 11 ein Ablaufdiagramm eines Verfahrens zum Bestimmen verfügbarer Zylindermodi ist;
• 12 ein Ablaufdiagramm eines Verfahrens zum Evaluieren ist, ob eine Zylinderabschaltung als Reaktion auf eine Zylinderanschaltungs-/-abschaltungsaktivität erfolgen kann oder nicht;
• 13 eine Sequenz ist, die eine Zylinderanschaltung und -abschaltung gemäß dem Verfahren nach 12 zeigt;
• 14 ein Ablaufdiagramm eines Verfahrens zum Evaluieren des Kraftstoffverbrauchs eines Motors als Grundlage zum selektiven Zulassen der Zylinderabschaltung ist;
• 15 ein Ablaufdiagramm eines Verfahrens zum Evaluieren des Kraftstoffverbrauchs eines Motors als Grundlage zum selektiven Zulassen der Zylinderabschaltung ist;
• 16 ein Ablaufdiagramm eines Verfahrens zum Evaluieren der Nockenphasenregelung eines Motors zum Auswählen von Motorzylindermodi ist;
• 17 eine Sequenz ist, die ein Auswählen von Motorzylindermodi als Reaktion auf eine Nockenphasenregelung eines Motors zeigt;
• 18 ein Ablaufdiagramm eines Verfahrens zum Auswählen eines Motorzylindermodus als Reaktion auf den Kraftstoffverbrauch eines Motors auf Grundlage des Betreibens eines Motors in unterschiedlichen Getriebegängen ist;
• 19 eine Sequenz ist, die ein Auswählen von Getriebegängen und eine tatsächliche Gesamtanzahl angeschalteter Zylinder zum Verbessern des Kraftstoffverbrauchs eines Motors zeigt;
• 20 ein Ablaufdiagramm eines Verfahrens zum Auswählen unterschiedlicher Motorzylindermodi während des Betreibens eines Fahrzeugs in unterschiedlichen Abbremsmodi ist;
• 21 eine Sequenz zum Betreiben eines Motorzylinders in unterschiedlichen Zylindermodi auf Grundlage eines Betreibens eines Fahrzeugs in unterschiedlichen Abbremsmodi ist;
• 22 ein Ablaufdiagramm zum Bestimmen ist, ob Zustände zum Betreiben eines Motors in unterschiedlichen Modi eines Motors mit variablem Hubraum (VDE) vorliegen;
• 23 ein Ablaufdiagramm eines Verfahrens zum Regulieren des Drucks im Ansaugkrümmer eines Motors ist;
• 24 eine Sequenz ist, welche die Regulierung des Drucks im Ansaugkrümmer eines Motors gemäß dem Verfahren nach 23 zeigt;
• 25 ein Ablaufdiagramm eines Verfahrens zum Regulieren des Drucks im Ansaugkrümmer eines Motors ist;
• 26 eine Betriebssequenz zum Regulieren des Drucks im Ansaugkrümmer eines Motors ist;
• 27A und 27B ein Ablaufdiagramm zum Einstellen von Motoraktoren zum Verbessern der Modusänderungen von Motorzylindern zeigen;
• 28A und 28B Sequenzen zum Verbessern von Zylindermodusänderungen zeigen;
• 29 ein Ablaufdiagramm zum Zuführen von Kraftstoff an einen Motor im Verlauf von Zylindermodusänderungen ist;
• 30 eine Sequenz ist, welche die Kraftstoffzufuhr an einen Motor im Verlauf von Zylindermodusänderungen zeigt;
• 31 ein Ablaufdiagramm eines Verfahren zur Regulierung des Motoröldrucks im Verlauf von Zylindermodusänderungen ist;
• 32 eine Sequenz ist, welche die Öldruckregulierung im Verlauf von Zylindermodusänderungen zeigt;
• 33 ein Ablaufdiagramm eines Verfahrens zum Verbessern der Klopfregulierung eines Motors im Verlauf von Zylindermodusänderungen ist;
• 34 eine Sequenz ist, welche die Klopfregulierung eines Motors im Verlauf unterschiedlicher Motorzylindermodi zeigt;
• 35 ein Ablaufdiagramm eines Verfahrens zum Einstellen der Funkenverstärkung ist;
• 36 eine Sequenz ist, die eine einstellbare Funkenverstärkung zeigt;
• 37 ein Ablaufdiagramm eines Verfahrens zum Bestimmen eines Klopfreferenzwerts in Abhängigkeit vom Zylindermodus ist;
• 38 eine Sequenz ist, die eine Auswahl eines Klopfreferenzwerts zeigt;
• 39 ein Ablaufdiagramm eines Verfahrens zum Auswählen von Motorzylindermodi bei vorliegendem Ventilverschleiß ist;
• 40 ein Ablaufdiagramm einer Sequenz zum Auswählen von Motorzylindermodi bei vorliegendem Ventilverschleiß ist;
• 41 ein Ablaufdiagramm zum Abfragen eines Sauerstoffsensors als Reaktion auf eine Zylinderabschaltung ist; und
• 42 ein Ablaufdiagramm zum Abfragen eines Nockenwellensensors als Reaktion auf eine Zylinderabschaltung ist.

The advantages described herein will become more fully apparent upon reading an example of an embodiment, referred to herein as the detailed description, whether read in isolation or with reference to the drawings, in which:

• 1A is a schematic representation of a single cylinder of an engine;
• 1B a schematic representation of the engine according to 1A which is integrated into a powertrain;
• 2A-2F show exemplary valve designs for four-cylinder engines with cylinders that can be deactivated;
• 3A and 3B show exemplary patterns of switched on and off cylinders of a four-cylinder engine;
• 4A-4C show exemplary valve designs for an eight-cylinder engine with cylinders that can be deactivated;
• 5A shows exemplary camshafts for a hydraulically operated valve deactivation system;
• 5B shows exemplary shut-off valve actuators for the hydraulically operated valve shut-off system used in 5A is shown;
• 5C shows an exemplary valve actuator for the hydraulically operated valve shut-off system used in 5A is shown;
• 5D shows an exemplary cylinder and valve deactivation sequence for the hydraulically operated valve deactivation system used in 5A is shown;
• 6A shows an exemplary camshaft for an alternative hydraulically operated valve deactivation system;
• 6B shows a cross-section of a camshaft and a socket for the hydraulically operated valve deactivation system used in 6A is shown;
• 6C shows exemplary valve shut-off valve actuators for the hydraulically operated valve shut-off system used in 6A is shown;
• 6D is an example cylinder and valve deactivation sequence for the hydraulically operated valve deactivation system used in 6A is shown;
• 7 is a flowchart of an example method for operating an engine with cylinder and valve deactivation;
• 8A is a flowchart of an exemplary method for selectively activating and deactivating cylinders and cylinder valves of an engine, with both deactivation and non-deactivation intake valves and only non-deactivation exhaust valves;
• 8B is a block diagram for estimating an amount of oil in a deactivated cylinder;
• 9 is an exemplary sequence for switching on and off cylinders and cylinder valves of an engine, with both deactivation and non-deactivation intake valves and only non-deactivation exhaust valves;
• 10 is a flowchart of an exemplary method for selectively enabling and disabling cylinders and cylinder valves of an engine, with both disabling and non-disabling intake valves and with non-disabling and disabling exhaust valves;
• 11 is a flowchart of a method for determining available cylinder modes;
• 12 is a flowchart of a method for evaluating whether or not cylinder deactivation can occur in response to cylinder activation/deactivation activity;
• 13 is a sequence that enables cylinder activation and deactivation according to the method of 12 shows;
• 14 is a flowchart of a method for evaluating the fuel consumption of an engine as a basis for selectively allowing cylinder deactivation;
• 15 is a flowchart of a method for evaluating the fuel consumption of an engine as a basis for selectively allowing cylinder deactivation;
• 16 is a flowchart of a method for evaluating cam phasing of an engine to select engine cylinder modes;
• 17 is a sequence showing selecting engine cylinder modes in response to cam phasing of an engine;
• 18 is a flowchart of a method for selecting an engine cylinder mode in response to engine fuel consumption based on operating an engine in different transmission gears;
• 19 is a sequence showing selecting transmission gears and an actual total number of cylinders engaged to improve fuel consumption of an engine;
• 20 is a flowchart of a method for selecting different engine cylinder modes while operating a vehicle in different deceleration modes;
• 21 is a sequence for operating an engine cylinder in different cylinder modes based on operating a vehicle in different deceleration modes;
• 22 a flowchart for determining whether conditions exist for operating an engine in different modes of a variable displacement engine (VDE);
• 23 is a flowchart of a method for regulating the pressure in the intake manifold of an engine;
• 24 is a sequence which allows the regulation of the pressure in the intake manifold of an engine according to the method of 23 shows;
• 25 is a flowchart of a method for regulating the pressure in the intake manifold of an engine;
• 26 is an operating sequence for regulating the pressure in the intake manifold of an engine;
• 27A and 27B show a flowchart for adjusting engine actuators to improve mode changes of engine cylinders;
• 28A and 28B Show sequences for improving cylinder mode changes;
• 29 is a flowchart for supplying fuel to an engine during cylinder mode changes;
• 30 is a sequence showing the fuel supply to an engine during cylinder mode changes;
• 31 is a flowchart of a method for regulating engine oil pressure during cylinder mode changes;
• 32 is a sequence showing oil pressure regulation during cylinder mode changes;
• 33 is a flowchart of a method for improving knock control of an engine during cylinder mode changes;
• 34 is a sequence showing the knock control of an engine over different engine cylinder modes;
• 35 is a flowchart of a method for adjusting spark gain;
• 36 is a sequence showing adjustable spark gain;
• 37 is a flowchart of a method for determining a knock reference value depending on the cylinder mode;
• 38 is a sequence showing a selection of a knock reference value;
• 39 is a flowchart of a method for selecting engine cylinder modes when valve wear is present;
• 40 is a flowchart of a sequence for selecting engine cylinder modes in the presence of valve wear;
• 41 is a flowchart for interrogating an oxygen sensor in response to cylinder deactivation; and
• 42 is a flowchart for interrogating a camshaft sensor in response to cylinder deactivation.

Detailed description

This description relates to systems and methods for selectively switching on and off cylinders and cylinder valves of an internal combustion engine. The engine may be 1A-6D Different procedures and expected operating sequences for an engine that includes shut-off valves are shown in 7-42 The different methods can be used together and with the 1A-6D systems shown.

It will be 1A in which an internal combustion engine 10 comprising a plurality of cylinders, one cylinder of which is 1A shown, is controlled by the electronic engine control system 12. The engine 10 consists of a cylinder head casting 35 and block 33, which include a combustion chamber 30 and cylinder walls 32. The piston 36 is positioned therein and reciprocates via a connection to the crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. A starter 96 (e.g., a low-voltage electric machine (operating at less than 30 volts)) includes a pinion shaft 98 and a pinion gear 95. The pinion shaft 98 can selectively drive the pinion gear 95 to engage the ring gear 99. The starter 96 can be mounted directly in the front of the engine or the rear of the engine. In some examples, the starter 96 can selectively supply torque to the crankshaft 40 via a belt or chain. In one example, the starter 96 is in a ground state when it is not engaging the engine crankshaft.

The combustion chamber 30 is shown communicating with the intake manifold 44 and the exhaust manifold 48 via an intake valve 52 and an exhaust valve 54, respectively. Each intake and exhaust valve may be operated by an intake camshaft 51 and an exhaust camshaft 53. The position of the intake camshaft 51 may be determined by the intake cam sensor 55. The position of the exhaust camshaft 53 may be determined by the exhaust cam sensor 57. An angular position of the intake valve 52 may be offset relative to the crankshaft 40 via the phasing device 59. An angular position of the exhaust valve 54 may be offset relative to the crankshaft 40 via the phasing device 58. The valve actuators detailed below may transfer mechanical energy from intake camshaft 51 to intake valve 52 and from exhaust camshaft 53 to exhaust valve 54. Furthermore, in other examples, a single camshaft may operate intake valve 52 and exhaust valve 54.

A fuel injector 66 is shown arranged to inject fuel directly into the cylinder 30, known to those skilled in the art as direct fuel injection. An optional fuel injector 67 is shown arranged to inject fuel into the cylinder 30 via an intake manifold, known to those skilled in the art as port fuel injection. The fuel injectors 66 and 67 deliver liquid fuel proportional to the pulse widths from the controller 12. The fuel is delivered to the fuel injectors 66 and 67 by a fuel system (not shown) that includes a fuel tank, a fuel pump, and a fuel rail (not shown). In one example, a two-stage, high-pressure fuel system may be used to generate higher fuel pressures.

Additionally, the intake manifold 44 is illustrated as communicating with the turbocharger compressor 162 and the engine air intake 42. In other examples, the compressor 162 may be a supercharger compressor. A shaft 161 mechanically couples the turbocharger turbine 164 to the turbocharger compressor 162. An optional electronic throttle or central throttle 62 adjusts a position of a throttle plate 64 to regulate airflow from the compressor 162 to the intake manifold 44. The pressure in the boost chamber 45 may be related to a throttle inlet pressure because the inlet of the throttle 62 is located within the boost chamber 45. The throttle outlet is located in the intake manifold 44. In some examples, a charge motion control valve 63 is located downstream of the throttle 62 and upstream of the intake valve 52 in an airflow direction into the engine 10 and is operated by the controller 12 to regulate airflow into the combustion chamber 30. A compressor recirculation valve 47 can be selectively set to a variety of positions between fully open and fully closed. A wastegate 163 can be set via the controller 12 to allow exhaust gases to selectively bypass the turbine 164 to control the speed of the compressor 162. An air cleaner 43 cleans air entering the engine air intake 42.

A distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 in response to the controller 12 via a spark plug 92. A wideband oxygen (UEGO) sensor 126 is shown coupled to the exhaust manifold 48, which is located upstream of the catalytic converter 70. Alternatively, the UEGO sensor 126 may be replaced with a binary oxygen sensor. A pressure sensor 127 is shown as an exhaust pressure sensor disposed in the exhaust manifold 48. Alternatively, the pressure sensor 127 may be disposed as a cylinder pressure sensor in the combustion chamber 30. The spark plug 92 may serve as an ion sensor for the ignition system 88.

In one example, the catalyst 70 may include multiple catalyst modules. In another example, multiple emission control devices, each including multiple modules, may be used. In one example, the catalyst 70 may be a three-way catalyst. Further, the catalyst 70 may include a particulate filter.

The control 12 is in 1A shown as a conventional microcomputer, including: microprocessor unit 102, input/output channels 104, read-only memory 106 (e.g., non-volatile memory), random access memory 108, keep-alive memory 110, and a conventional data bus. The controller 12 is shown receiving various signals from sensors coupled to the engine 10, in addition to those signals previously discussed, including: engine coolant temperature (ECT) from temperature sensor 112 coupled to a cooling sleeve 114; an engine mount with built-in vibration and/or motion sensors 117 that can provide feedback for compensating for and evaluating engine noise, vibration, and harshness; a position sensor 134 coupled to an accelerator pedal 130 for sensing the force exerted by a foot 132; a position sensor 154 coupled to a brake pedal 150 for sensing the force exerted by a foot 152; a measurement of engine intake manifold pressure (MAP) from pressure sensor 122 coupled to intake manifold 44; an engine position sensor from a Hall sensor 118 that senses the position of a crankshaft 40; a measurement of the mass of air entering the engine from sensor 120; and a measurement of throttle position from sensor 68. Atmospheric pressure may also be sensed for processing by controller 12 (sensor not shown). In a preferred aspect of the present description, engine position sensor 118 generates a predetermined number of evenly spaced pulses every revolution of the crankshaft, from which engine speed (RPM) can be determined. The controller 12 may also receive information from other sensors 24, which may include, but are not limited to, engine oil pressure sensors, ambient pressure sensors, and engine oil temperature sensors.

During operation, each cylinder in the engine 10 typically undergoes a four-stroke cycle: The cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. A cylinder cycle for a four-stroke engine corresponds to two revolutions of the engine, and one engine cycle also corresponds to two revolutions. During the intake stroke, exhaust valve 54 generally closes and intake valve 52 opens. Air is introduced into combustion chamber 30 via intake manifold 44, and piston 36 moves toward the bottom of the cylinder, increasing the volume in combustion chamber 30. The position at which piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when combustion chamber 30 is at its largest volume) is typically referred to by those skilled in the art as bottom dead center (BDC).

During the compression stroke, intake valve 52 and exhaust valve 54 are closed. Piston 36 moves toward cylinder head casting 35, compressing the air in combustion chamber 30. The point at which piston 36 is at the end of its stroke and closest to cylinder head casting 35 (e.g., when combustion chamber 30 is at its smallest volume) is typically referred to by those skilled in the art as top dead center (TDC). In a process referred to herein as injection, fuel is introduced into the combustion chamber. In a process referred to herein as ignition, the injected fuel is ignited by known ignition means, such as spark plug 92, resulting in combustion.

During the power stroke, the expanding gases push the piston 36 back to BDC. The crankshaft 40 converts piston motion into rotating shaft torque. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the combusted air-fuel mixture to the exhaust manifold 48, and the piston returns to TDC. It should be noted that the foregoing is merely an example, and that the timing for opening and/or closing the intake and exhaust valves may vary, for example, to provide positive or negative valve overlap, late intake valve closing, or various other examples.

The driver demand torque may be determined from a position of the accelerator pedal 130 and the speed of the vehicle. For example, the accelerator pedal position and the vehicle speed may be entered into a table that outputs a driver demand torque. The driver demand torque may represent a desired engine torque or a torque at a location along a driveline including the engine. The engine torque may be determined from the driver demand torque by adjusting the driver demand torque, gear ratios, axle ratios, and other driveline components.

It will now 1B referred to, whereby 1B is a block diagram of a vehicle 125 including a powertrain 100. The powertrain according to 1B includes the 1A shown engine 10. The powertrain 100 may be driven by the engine 10. The engine torque may be adjusted via an engine torque actuator 191, which may be a fuel injector, a camshaft, a throttle, or other device. The engine crankshaft 40 is shown coupled to a torque converter 156. In particular, the engine crankshaft 40 is mechanically coupled to a torque converter impeller 285. A torque sensor 41 provides torque feedback and may be used to evaluate engine noise, vibration, and harshness. The torque converter 156 also includes a turbine 186 for outputting torque to a transmission input shaft 170. The transmission input shaft 170 mechanically couples the torque converter 156 to the automatic transmission 158. The torque converter 156 also includes a torque converter bypass clutch (TCC) 121. Torque is transferred directly from the impeller 185 to the turbine 186 when the TCC is locked. The TCC is electrically operated by the controller 12. Alternatively, the TCC may be hydraulically locked. In one example, the torque converter may be referred to as a component of the transmission.

When the torque converter clutch 121 is fully disengaged, the torque converter 156 transmits engine torque to the automatic transmission 158 via fluid transfer between the torque converter turbine 186 and the torque converter impeller 185, enabling torque increase. In contrast, when the torque converter clutch 121 is fully engaged, the engine output torque is transmitted directly to an input shaft 170 of the transmission 158 via the torque converter clutch. Alternatively, the torque converter clutch 121 may be partially engaged, allowing the amount of torque transmitted directly to the transmission to be adjusted. The controller 12 may be configured to adjust the amount of torque transmitted through the torque converter 121 by adjusting the torque converter clutch in response to various engine operating conditions or based on a driver-based engine operating request.

The automatic transmission 158 includes gears (e.g., reverse and gears 1-6) 136 and forward clutches 135 for the gears. The gears 136 (e.g., 1-10) and clutches 135 may be selectively engaged to propel a vehicle. The torque output from the automatic transmission 158 may, in turn, be transmitted to the wheels 116 to propel the vehicle via an output shaft 160. Specifically, the automatic transmission 158 may transmit input drive torque at the input shaft 170 in response to a vehicle driving condition before transmitting output drive torque to the wheels 116.

Furthermore, a frictional force may be applied to the wheels 116 by applying the wheel brakes 119. In one example, the wheel brakes 119 may be applied in response to the driver, as in 1A shown depressing a brake pedal with their foot. In other examples, the controller 12 or a controller coupled to the controller 12 may cause the wheel brakes to be applied. Similarly, a frictional force on the wheels 116 may be reduced by releasing the wheel brakes 119 in response to the driver removing their foot from a brake pedal. Further, the vehicle brakes may apply a frictional force to the wheels 116 via the controller 12 as part of an automated engine stop procedure.

The controller 12 may be configured to receive inputs from the motor 10 as shown in 1A shown in detail, and control a torque output of the engine and/or the operation of the torque converter, transmission, clutches, and/or brakes accordingly. As an example, engine torque output may be controlled by adjusting a combination of ignition timing, fuel pulse width, fuel pulse duty, and/or air charge by controlling throttle opening and/or valve timing, valve lift, and boost pressure for turbocharged or supercharged engines. In the case of a diesel engine, controller 12 may control engine torque output by controlling a combination of fuel pulse width, fuel pulse duty, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control engine torque output. Controller 12 may also control torque output and electrical energy production from a DISG by adjusting the current flowing to field and/or armature windings of the DISG, as is known in the art.

If the conditions for idle shutdown are met, the controller 12 may initiate an engine shutdown by cutting off fuel and/or ignitions to the engine. However, in some examples, the engine may continue to rotate. To maintain a certain level of torsional stress in the transmission, the controller 12 may further ground rotating elements of the transmission 158 to a housing 159 of the transmission and thereby to the frame of the vehicle. If the conditions for engine restart are met and/or a vehicle operator desires to start the vehicle, the controller 12 may restart the engine 10 by cranking the engine 10 and resuming cylinder combustion.

The intake manifold 44 of the engine 10 is in pneumatic communication with a vacuum reservoir 177 via valve 176. The vacuum can provide vacuum to the brake booster 178, the heating/ventilation/cooling system 179, the wastegate actuator 180, and other vacuum-operated systems. In one example, the valve 176 can be a solenoid valve that can be selectively opened and closed to allow or prevent communication between the intake manifold 44 and vacuum pickups 178-180. Additionally, a vacuum source 183, such as a pump or ejector, can selectively provide vacuum to the engine intake manifold 44 so that the engine 10 can be restarted if there is a leak through the restrictor 62, wherein the pressure in the engine intake manifold is less than atmospheric pressure. The vacuum source 183 can also selectively supply vacuum to the vacuum receivers 178-180 via a three-way valve 171, for example, when the vacuum level in the vacuum reservoir 177 is below a threshold. The volume of the intake manifold 44 can be adjusted via a variable plenum volume valve 175.

At this point, 2A , which illustrates an exemplary configuration of engine 10. In this configuration, engine 10 is an inline four-cylinder engine having a first valve configuration. The portions of the engine's combustion chambers formed in cylinder head casting 35, which may also be referred to as part of a cylinder, are numbered 1-4 according to cylinder numbers 1-4 as indicated for each engine cylinder 200. In this example, each combustion chamber is shown with two intake valves and two exhaust valves. Deactivation intake valves 208 are shown as poppet valves with an X through the poppet valve rod.

Shutdown exhaust valves 204 are shown as poppet valves with an X through the poppet valve stem. Non-shutdown inlet valves 206 are shown as poppet valves. Non-shutdown exhaust valves 202 are also shown as poppet valves.

Camshaft 270 is shown in mechanical communication with non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. Camshaft 270 is also shown in mechanical communication with non-deactivation intake valves 206 via non-deactivation intake valve actuators 251. Camshaft 270 is shown in mechanical communication with deactivation exhaust valves 204 via deactivation exhaust valve actuators 252. Camshaft 270 is also shown in mechanical communication with deactivation intake valves 208 via deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

In this configuration, cylinders 2 and 3 are shown with deactivation intake valves 208 and deactivation exhaust valves 204. Cylinders 1 and 4 are shown with non-deactivation intake valves 206 and non-deactivation exhaust valves 202. However, the non-deactivation intake valves 206 and non-deactivation exhaust valves 202 may be replaced with deactivation intake valves and deactivation exhaust valves so that all engine cylinders can be selectively deactivated.

The interpretation according to 2A allows for joint or separate deactivation of cylinders 2 and 3. Since both the intake and exhaust valves of cylinders 2 and 3 are deactivating, these cylinders are deactivated by closing both the intake and exhaust valves for an entire engine cycle and ending fuel flow to cylinders 2 and 3. For example, with a firing order of 1-3-4-2, the engine can fire in a sequence of 1-2-1-2 or 1-3-2-1-4-2 or 1-3-2-1-3-2-1-4-2 or other combinations in which cylinders 1 and 2 combust air and fuel. However, if each of cylinders 1-4 included deactivation intake and exhaust valves, cylinders 1 and 2 might not fire (e.g., combust air and fuel) during some engine cycles. For example, the engine's firing order may be 3-4-3-4, or 1-3-2-1-3-2, or 3-4-2-3-4-2, or other combinations in which cylinders 1 and 2 do not combust air or fuel during an engine cycle. It is noteworthy that a deactivated cylinder may trap exhaust gases or fresh air, depending on whether fuel is injected into the cylinder and combusted before the exhaust valves are deactivated in a closed position.

2A also shows a first knock sensor 203 and a second knock sensor 205. The first knock sensor 203 is located closer to cylinders 1 and 2. The second knock sensor 205 is located closer to cylinders 3 and 4. The first knock sensor may be used to detect knock from cylinders 1 and 2 during some conditions and knock from cylinders 1-4 during other conditions. Likewise, the second knock sensor 205 may be used to detect knock from cylinders 3 and 4 during some conditions and knock from cylinders 1-4 during other conditions. Alternatively, the knock sensors may be mechanically coupled to the engine block.

It will now 2B , which shows an alternative exemplary configuration of the engine 10. In this configuration, the engine 10 is an inline four-cylinder engine in which a portion of the cylinders are provided with only deactivation intake valves. Portions of the engine's combustion chambers formed in the cylinder head casting 35 are again numbered 1-4, as indicated in the case of the engine cylinders 200. Each cylinder is shown with two intake valves and two exhaust valves. Cylinders 1-4 include non-deactivation exhaust valves 202 and no non-deactivation exhaust valves. Cylinders 1 and 4 also include non-deactivation intake valves 206 and no non-deactivation intake valves. Cylinders 2 and 3 include deactivation intake valves 208 and no non-deactivation intake valves.

The camshaft 270 is shown in mechanical communication with the non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. The camshaft 270 is also in mechanical communication with the non-deactivation intake valves 206 via non-deactivation intake valve actuators 251. The camshaft 270 is also in mechanical communication with the deactivation intake valves 208 via deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with valve actuators for activity reduction, however, each valve is driven by a Valve actuator accompanied (e.g., the non-shutdown valves are accompanied by non-shutdown valve actuators and the shutdown valves are accompanied by shutdown valve actuators).

The interpretation according to 2B allows cylinders 2 and 3 to be deactivated together or separately via deactivation intake valves 208. The exhaust valves of cylinders 2 and 3 continue to close and open during an engine cycle as the engine rotates. Since only the intake valves of cylinders 2 and 3 deactivate, these cylinders are deactivated by closing only the intake valves for an entire engine cycle, terminating fuel flow to cylinders 2 and 3. Again, with a 1-3-4-2 firing order, the engine can fire in a 1-2-1-2 or 1-3-2-1-4-2 or 1-3-2-1-3-2-1-4-2 order, or other combinations in which cylinders 1 and 2 combust air and fuel. It is notable that in this design, a deactivated cylinder will inhale exhaust and expel exhaust during the exhaust stroke of the deactivated cylinder. Specifically, exhaust gas is drawn into the deactivated cylinder when the exhaust valve of the deactivated cylinder opens near the beginning of the exhaust stroke, and exhaust gas is expelled from the deactivated cylinder when the piston of the cylinder approaches top dead center in the exhaust stroke before the exhaust valve closes.

In other examples, cylinders 1 and 4 may include deactivation intake valves, while cylinders 2 and 3 may include non-deactivation intake valves. Otherwise, the valve arrangement may be the same.

At this point, 2C , which shows an alternative exemplary engine configuration of engine 10. In this configuration, engine 10 is an inline four-cylinder engine, and all engine cylinders include deactivation intake valves 208, and none of the cylinders include deactivation exhaust valves. Portions of the engine's combustion chambers formed in cylinder head casting 35 are again numbered 1-4, as indicated in the case of engine cylinders 200. Each cylinder is shown with two intake valves and two exhaust valves. Cylinders 1-4 include deactivation intake valves 208 and no deactivation intake valves. Cylinders 1-4 also include non-deactivation exhaust valves 202 and no deactivation exhaust valves. Engine 10 is also shown with a first knock sensor 220 and a second knock sensor 221.

The camshaft 270 is shown in mechanical communication with the non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. The camshaft 270 is also in mechanical communication with the deactivation intake valves 208 and deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

The interpretation according to 2C allows cylinders 1-4 to be deactivated in any combination during an engine cycle by only deactivating the intake valves of cylinders 1-4. The exhaust valves of cylinders 1-4 continue to close and open during an engine cycle as the engine rotates. Furthermore, cylinders 1-4 can be deactivated by closing only the intake valves and stopping fuel flow to cylinders 1-4 for an entire engine cycle, or combinations thereof. With a firing order of 1-3-4-2, the engine can fire in a sequence of 1-2-1-2 or 1-3-2-1-4-2 or 1-3-2-1-3-2-1-4-2 or other combinations of cylinders 1-4, since each cylinder can be deactivated individually and without deactivating the other engine cylinders. It is noteworthy that in this design, a deactivated cylinder draws exhaust gas into itself and expels exhaust gas during the exhaust stroke of the deactivated cylinder. Specifically, exhaust gas is drawn into the deactivated cylinder when the exhaust valve of the deactivated cylinder opens near the beginning of the exhaust stroke, and exhaust gas is expelled from the deactivated cylinder when the piston of the cylinder approaches top dead center in the exhaust stroke before the exhaust valve closes.

At this point, 2D which shows an alternative engine design of the engine 10. The system according to 2D is with the system according to 2A identical, except that the system is 2D an intake camshaft 271 and an exhaust camshaft 272. The portions of the engine's combustion chambers formed in the cylinder head casting 35, which may also be referred to as part of a cylinder, are numbered 1-4 according to the cylinder numbers 1-4 as indicated for each engine cylinder 200.

Camshaft 271 is shown in mechanical communication with non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. Camshaft 272 is shown in mechanical communication with non-deactivation intake valves 206 via non-deactivation intake valve actuators 251. Camshaft 271 is shown in mechanical communication with deactivation exhaust valves 204 via deactivation intake valve actuators 252. Camshaft 272 is shown in mechanical communication with deactivation intake valves 208 via deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

At this point, 2E which shows an alternative engine design of the engine 10. The system according to 2E is with the system according to 2B identical, except that the system is 2E an intake camshaft 271 and an exhaust camshaft 272. The portions of the engine's combustion chambers formed in the cylinder head casting 35, which may also be referred to as part of a cylinder, are numbered 1-4 according to the cylinder numbers 1-4 as indicated for each engine cylinder 200.

Camshaft 271 is shown in mechanical communication with non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. Camshaft 272 is in mechanical communication with non-deactivation intake valves 206 via non-deactivation intake valve actuators 251. Camshaft 272 is also in mechanical communication with deactivation intake valves 208 and deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

At this point, 2F which shows an alternative engine design of the engine 10. The system according to 2F is with the system according to 2C identical, except that the system is 2F an intake camshaft 271 and an exhaust camshaft 272. The portions of the engine's combustion chambers formed in the cylinder head casting 35, which may also be referred to as part of a cylinder, are numbered 1-4 according to the cylinder numbers 1-4 as indicated for each engine cylinder 200.

Camshaft 271 is shown in mechanical communication with non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. Camshaft 272 is shown in mechanical communication with deactivation intake valves 208 and deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

The 2A-2F The shut-off valve actuators shown can be operated by a lever type (see e.g. 6B) , sleeve type (see e.g. US patent application US 2014 / 0 303 873 A1 entitled “ Position Detection For Lobe Switching Camshaft System“, filed on December 12, 2013 and incorporated herein by reference for all purposes), a cam type or a lash adjuster type. Furthermore, any of the 2A-2F shown cylinder heads mechanically to one and the same block 33, in 1A shown, be coupled. The 2A-2F The cylinder heads shown may be formed from the same casting, and the shut-off and non-shut-off valve actuators for each cylinder head design may be varied as shown in 2A-2F shown.

It will now 3A which shows an example cylinder deactivation pattern. In 3A Cylinder 4 of engine 10 is shown crossed with an X to indicate that cylinder 4 can be deactivated during an engine cycle while cylinders 1, 2, and 3 remain activated. Activated cylinders are shown without an X to indicate that the cylinders are activated. A cylinder can be deactivated via the 2C system shown may be deactivated during an engine cycle. Alternatively, cylinder 1 may be the only deactivated cylinder during an engine cycle if the engine 10 is 2C shown. Cylinder 2 may be the only deactivated cylinder during an engine cycle when the engine 10 is 2A , 2B and 2C is designed. Likewise Cylinder 3 may be the only deactivated cylinder during an engine cycle when the engine 10 is operating as in 2A , 2B and 2C The 200 cylinders are shown in a row.

It will now 3B which shows a different cylinder deactivation pattern. In 3B Cylinders 2 and 3 of engine 10 are shown crossed with an X to indicate that cylinders 2 and 3 may be deactivated during an engine cycle while cylinders 1 and 4 remain activated. Activated cylinders are shown without an X to indicate that the cylinders are activated. Cylinders 2 and 3 may be deactivated via the 2A , 2B and 2C systems shown are deactivated during an engine cycle. Alternatively, cylinders 1 and 4 may be the only deactivated cylinders during an engine cycle when the engine 10 is 2C shown. For the 2 and 3 The deactivated cylinders shown are cylinders whose valves are closed to prevent fuel flow from the engine intake manifold to the engine exhaust manifold while the engine is running, and where fuel injection to the deactivated cylinders ceases. Sparks provided to the deactivated cylinders may also be stopped. The 200 cylinders are shown in a row.

In this way, individual cylinders or groups of cylinders can be deactivated. Furthermore, deactivated cylinders can be reactivated from time to time to reduce the possibility of engine oil entering the engine cylinders. For example, a cylinder can fire 1-4-1-4-1-4-2-1-4-3-1-4-1-4 to reduce the possibility of oil entering cylinders 2 and 3 after cylinders 2 and 3 have been deactivated.

At this point, 4A , which illustrates another exemplary configuration of engine 10. The portions of the engine's combustion chambers formed in cylinder heads 35 and 35a, which may also be referred to as part of a cylinder, are numbered 1-8 according to cylinder numbers 1-8 as indicated for each engine cylinder. Engine 10 includes a first cylinder bank 401, including cylinders 1-4 in cylinder head casting 35, and a second cylinder bank 402, including cylinders 5-8 in cylinder head casting 35a. In this configuration, engine 10 is a V-eight engine including deactivation intake valves 208 and non-deactivation intake valves 206. The engine 10 also includes deactivation exhaust valves 204 and non-deactivation exhaust valves 202. The valves regulate airflow from the engine intake manifold to the engine exhaust manifold via the engine cylinder 200. In some examples, the deactivation exhaust valves 204 may be replaced with non-deactivation exhaust valves 202 to reduce system costs while maintaining the capacity to deactivate engine cylinders (e.g., terminating fuel flow to the deactivated cylinder and terminating airflow from an engine intake manifold to an engine exhaust manifold via a cylinder while the engine is rotating). Accordingly, in some examples, the engine 10 may include only non-deactivation exhaust valves 202 in combination with deactivation intake valves 208 and non-deactivation intake valves 206.

In this example, cylinders 5, 2, 3, and 8 are shown as having valves that are always on, so that air flows from the engine intake manifold to the engine exhaust manifold via cylinders 5, 2, 3, and 8 when the engine is rotating. Cylinders 1, 6, 7, and 4 are shown as having valves that are selectively deactivated in closed positions, so that air does not flow from the engine intake manifold to the engine exhaust manifold via cylinders 1, 6, 7, and 4, respectively, when the valves in the corresponding cylinders are deactivated in a closed state during an engine cycle. In other examples, such as in 4B , the cylinders that have valves always on are cylinders 5 and 2. The actual total number of cylinders that have valves always on may be based on vehicle mass and engine displacement or other considerations.

Valves 202, 204, 206, and 208 are opened and closed via a single camshaft 420. Valves 202, 204, 206, and 208 may be in mechanical communication with the single camshaft 320 via pushrods and conventional lash adjusters or de-energizing adjusters or hydraulic cylinders, as described in the US patent application US 2003 / 0 145 722 A1 and the title “ Hydraulic Cylinder Deactivation with Rotary Sleeves”, filed on February 1, 2002 and incorporated herein by reference for all purposes. Alternatively, the valves 202, 204, 206 and 208 may be controlled by conventional roller cam followers and/or valve actuators as shown in 6A , 6B and 5C In still other examples, the valves may have shrouded cams, as shown in US patent application US 2014 / 0 303 873 A1 shown.

Camshaft 420 is shown in mechanical communication with non-deactivation exhaust valves 202 via non-deactivation exhaust valve actuators 250. Camshaft 420 is also in mechanical communication with non-deactivation intake valves 206 via non-deactivation intake valve actuators 251. Camshaft 420 is also in mechanical communication with deactivation intake valves 208 and deactivation intake valve actuators 253. Camshaft 420 is also in mechanical communication with deactivation exhaust valves 204 via deactivation intake valve actuators 252. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

At this point, 4A , which illustrates another exemplary configuration of engine 10. The portions of the engine's combustion chambers formed in cylinder heads 35 and 35a, which may also be referred to as part of a cylinder, are numbered 1-8 according to cylinder numbers 1-8 as indicated for each engine cylinder. Engine 10 includes a first cylinder bank 401, including cylinders 1-4 in cylinder head casting 35, and a second cylinder bank 402, including cylinders 5-8 in cylinder head casting 35a. In this configuration, engine 10 is also a V-eight engine including deactivation intake valves 208 and non-deactivation intake valves 206. The engine 10 also includes deactivation exhaust valves 204 and non-deactivation exhaust valves 202. The valves regulate airflow from the engine intake manifold to the engine exhaust manifold via the engine cylinder 200. The valves 202, 204, 206, and 208 are operated via an intake camshaft 51 and an exhaust camshaft 53. Each cylinder bank includes an intake camshaft 51 and an exhaust camshaft 53.

In some examples, the deactivation exhaust valves may be replaced with non-deactivation exhaust valves 204 to reduce system costs while maintaining the capacity to deactivate engine cylinders (e.g., terminating fuel flow to the deactivated cylinder and terminating airflow from an engine intake manifold to an engine exhaust manifold via a cylinder while the engine is rotating). Accordingly, in some examples, the engine 10 may include only non-deactivation exhaust valves 202 in combination with deactivation intake valves 208 and non-deactivation intake valves 206.

In this example, cylinders 5 and 2 are shown as having always-on valves so that air flows from the engine intake manifold to the engine exhaust manifold via cylinders 5 and 2 when the engine is running. Cylinders 1, 3, 4, 6, 7, and 8 are shown as having intake and exhaust valves that are selectively deactivated in closed positions so that air does not flow from the engine intake manifold to the engine exhaust manifold via cylinders 1, 3, 4, 6, 7, and 8, respectively, when the valves in the corresponding cylinders are deactivated in a closed state. In this example, the cylinders are deactivated by deactivating the intake and exhaust valves of the cylinder being deactivated. For example, cylinder 3 may be deactivated so that air does not flow through cylinder 3 via deactivating valves 208 and 204.

Valves 202, 204, 206 and 208 are opened and closed by four camshafts. Valves 202, 204, 206 and 208 can be opened and closed by the 6A , 6B and 5C The valve actuators or hydraulic cylinders or tappets shown, which can deactivate the valves, are in mechanical communication with a camshaft. 4A and 4B The engines shown have a firing order of 1-5-4-2-6-3-7-8.

The engine 10 is also shown with a first knock sensor 420, a second knock sensor 421, a third knock sensor 422, and a fourth knock sensor 423. Accordingly, the first cylinder bank 401 includes the first knock sensor 420 and the second knock sensor 421. The first knock sensor 420 may detect knock in cylinder numbers 1 and 2. The second knock sensor 421 may detect knock in cylinder numbers 3 and 4. The second cylinder bank 402 includes the third knock sensor 422 and the fourth knock sensor 423. The third knock sensor 422 may detect knock in cylinders 5 and 6. The fourth knock sensor 423 may detect knock in cylinders 7 and 8.

The exhaust camshaft 53 is shown in mechanical communication with the non-deactivation exhaust valves 202 via the non-deactivation exhaust valve actuators 250. The intake camshaft 51 is in mechanical communication with the non-deactivation intake valves 206 via the non-deactivation intake valve actuators 251. The exhaust camshaft 53 is also in mechanical communication with the deactivation exhaust valves 204 deactivation intake valve actuators 252. The intake camshaft 51 is also in mechanical communication with the deactivation intake valves 208 via the deactivation intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivation valves are accompanied by non-deactivation valve actuators and the deactivation valves are accompanied by deactivation valve actuators).

The 4B The cylinder head design shown can be integrated into vehicles that have a lower mass than the vehicles in which the 4A The cylinder head design shown is included. The design according to 4B can be integrated into a vehicle with lower mass, since vehicles with lower mass can only use two cylinders to travel at a constant highway speed. Conversely, the design according to 4A be integrated into vehicles with higher mass, since vehicles with a higher mass can use four cylinders to travel at a constant highway speed. Likewise, the cylinder heads used in the 2A-2F shown and have a lower actual total number of cylinders that are not deactivating, are integrated into vehicles with lower mass. The 2A-2F Cylinder heads shown, which have a higher actual total number of cylinders that are not deactivating, can be integrated in vehicles with higher mass. In addition, the number of cylinders in the cylinder head castings used in 2A-4C represented that are not deactivating cylinders are based on the vehicle's final drive ratio. For example, if a vehicle has a lower final drive ratio (e.g., 2.69:1 compared to 3.73:1), a cylinder head design with a lower actual total number of non-deactivating cylinders may be selected, thus improving highway driving efficiency. Consequently, different vehicles with different masses and final drive ratios may incorporate the same engine block and cylinder head castings, but the actual total number of deactivating and non-deactivating valve actuators may vary between different vehicles.

At this point, 4C , which illustrates another exemplary configuration of engine 10. The portions of the engine's combustion chambers formed in cylinder heads 35 and 35a, which may also be referred to as part of a cylinder, are numbered 1-8 according to cylinder numbers 1-8 as indicated for each engine cylinder. Engine 10 includes a first cylinder bank 401, including cylinders 1-4 in cylinder head casting 35, and a second cylinder bank 402, including cylinders 5-8 in cylinder head casting 35a. In this configuration, engine 10 is also a V-eight engine including deactivation intake valves 208 and non-deactivation intake valves 206. The engine 10 also includes non-deactivation exhaust valves 202. The valves regulate airflow from the engine intake manifold to the engine exhaust manifold via the engine cylinder 200. The valves 202, 206, and 208 are operated via an intake camshaft 51 and an exhaust camshaft 53. Each cylinder bank includes an intake camshaft 51 and an exhaust camshaft 53.

In this example, all engine exhaust valves 202 are non-deactivating. The exhaust camshaft 53 is shown in mechanical communication with the non-deactivating exhaust valves 202 via the non-deactivating exhaust valve actuators 250. The intake camshaft 51 is in mechanical communication with the non-deactivating intake valves 206 via the non-deactivating intake valve actuators 251. The intake camshaft 51 is also in mechanical communication with the deactivating intake valves 208 via the deactivating intake valve actuators 253. In the figure, some intake and exhaust valves are not shown with activity reduction valve actuators, however, each valve is accompanied by a valve actuator (e.g., the non-deactivating valves are accompanied by non-deactivating valve actuators and the deactivating valves are accompanied by deactivating valve actuators).

The 4A-4C The shut-off valve actuators shown can be operated by a lever type (see e.g. 6B) , sleeve type (see e.g. US patent application US 2014 / 0 303 873 A1 entitled “ Position Detection For Lobe Switching Camshaft System“, filed on December 12, 2013 and incorporated herein by reference for all purposes), a cam type or a lash adjuster type. Furthermore, any of the 4A-4C shown cylinder heads mechanically to one and the same block 33, in 1A shown, be coupled. The 4A-4C The cylinder heads 35 shown may be formed from one and the same casting, and the deactivation and non-deactivation valve actuators for each cylinder head design may be varied, as shown in 4A-4C Likewise, the 4A-4C shown cylinder heads 35a may be formed from one and the same casting, and the deactivation and non-deactivation valve actuators for each cylinder head design may be varied as shown in 4A-4C shown.

At this point, 5A , which illustrates an exemplary valve drive system. The depicted embodiment may represent a mechanism for an inline four-cylinder engine or one of two mechanisms for a V-8 engine. Similar mechanisms with four different numbers of engine cylinders are possible. The valve drive system 500 includes an intake camshaft 51 and an exhaust camshaft 53. A chain, gear, or belt 599 mechanically couples the camshaft 51 and the camshaft 53 so that they rotate together at a same speed. In particular, the chain 599 mechanically couples a drive gear 520 to a drive gear 503.

The exhaust camshaft 53 includes cylindrical pivot bearings 504a, 504b, 504c, and 504d, which rotate in respective valve bodies 501a, 501b, 501c, and 501d. The valve bodies 501a, 501b, 501c, and 501d are shown integrated into an exhaust camshaft base 502, which may be part of a cylinder head casting 35. Discontinuous metering grooves 571a, 571b, 571c, and 571d are integrated into the bearing journals 504a, 504b, 504c, and 504d. The discontinuous metering grooves 571a, 571b, 571c, and 571d may be 1A shown crankshaft 40 to allow oil flow through the journals 504a, 504b, 504c and 504d in accordance with a desired engine crankshaft angular range, so that the 5B The exhaust valve actuators shown are switched off at a desired crank angle, thereby stopping the air flow from the engine cylinders. The lands 505a, 505b, 505c and 505d prevent the oil flow to the 5B shown valve actuators when the corresponding lands cover respective valve body outlets 506, 508, 510 and 512.

The oil can be fed via the valve body outlets 506, 508, 510 and 512 to the 5B shown valve actuators. Pressurized oil from oil pump 580 can selectively flow through valve body inlets 570, 572, 574, and 576, metering grooves 571a, 571b, 571c, and 571d, and the valve body outlets when the lands are not blocking valve body inlets and outlets 506, 508, 510, and 512. The pressurized oil can deactivate the valve actuators, as described in more detail below. Lands 505a, 505b, 505c, and 505d selectively open and close access to valve bodies 501a, 501b, 501c, and 501d for pressurized oil from oil pump 580 as exhaust camshaft 53 rotates. The exhaust camshaft 53 also includes cams 507a, 507b, 509a, 509b, 511a, 511b, 513a and 513b to open and close the exhaust valves as the cam lift increases and decreases in response to the rotation of the exhaust camshaft.

In one example, pressurized oil selectively flows through metering groove 571a via valve body inlet 570 to the exhaust valve actuators for cylinder number one. Cams 507a and 507b can provide a mechanical force to lift the exhaust valves of cylinder number one of a four- or eight-cylinder engine as exhaust camshaft 53 rotates. Similarly, pressurized oil selectively flows through metering groove 571b via valve body inlet 572 to the exhaust valve actuators for cylinder number two. Cams 509a and 509b can provide a mechanical force to lift the exhaust valves of cylinder number two of the four- or eight-cylinder engine as exhaust camshaft 53 rotates. Similarly, pressurized oil selectively flows through metering groove 571c via valve body inlet 574 to the exhaust valve actuators for cylinder number three. Cams 511a and 511b can provide mechanical force to lift the exhaust valves of cylinder number three of a four- or eight-cylinder engine when exhaust camshaft 53 rotates. Additionally, pressurized oil selectively flows through metering groove 571d via valve body inlet 576 to the exhaust valve actuators for cylinder number four. Cams 513a and 513b can provide mechanical force to lift the exhaust valves of cylinder number four of a four- or eight-cylinder engine when exhaust camshaft 53 rotates. Thus, exhaust camshaft 53 can provide force to open the poppet valves of a cylinder bank.

The intake camshaft 51 includes cylindrical journals 521a, 521b, 521c, and 521d, which rotate within respective valve bodies 540a, 540b, 540c, and 540d. The valve bodies 540a, 540b, 540c, and 540d are shown integrated into an intake camshaft base 522, which may be part of a cylinder head casting 35. Continuous metering grooves 551a, 551b, 551c, and 551d are integrated into the journals 521a, 521b, 521c, and 521d. However, in some examples, the continuous metering grooves 551a, 551b, 551c, and 551d may be omitted, and the oil may be supplied directly to the intake valve actuators by a pump 580.

Pressurized oil flows via a passage or channel 581 from the oil pump 580 to control valves 586, 587, 588, and 589. The control valve 586 can be opened to allow oil to flow into the valve body inlet 550, the metering groove 551a, and the valve body outlet 520a, before the oil flows via passage 520b to the intake valve actuators of cylinder number one. Pressurized oil is also supplied to the inlet 570 via a passage or line 524c. Thus, by closing the valve 586, a Deactivation of the intake and exhaust valves of cylinder number one can be prevented. Outlet 506 supplies oil to accumulator 506b and the exhaust valve actuators for cylinder number one.

The selective operation of the intake and exhaust valves for cylinder number two is similar to the selective operation of the intake and exhaust valves for cylinder number one. Specifically, pressurized oil flows via passage or channel 581 from oil pump 580 to valve 587, which can be opened to allow oil to flow into valve body inlet 552, metering groove 551b, and valve body outlet 524a before flowing to the intake valve actuators of cylinder number two via passage 524b. Pressurized oil is also supplied to valve body inlet 572 via a passage or line 524c. Thus, closing valve 587 can prevent deactivation of the intake and exhaust valves of cylinder number two. Outlet 508 supplies oil to accumulator 508b and the exhaust valve actuators for cylinder number two.

The selective operation of the intake and exhaust valves for cylinder number three is similar to the selective operation of the intake and exhaust valves for cylinder number one. For example, pressurized oil flows via passage or channel 581 from oil pump 580 to valve 588, which can be opened to allow oil to flow into valve body inlet 554, metering groove 551c, and valve body outlet 526a before flowing to the intake valve actuators of cylinder number three via passage 526b. Pressurized oil is also supplied to valve body inlet 574 via a passage or line 526c. Thus, closing valve 588 can prevent deactivation of the intake and exhaust valves of cylinder number three. Outlet 510 supplies oil to accumulator 510b and the exhaust valve actuators for cylinder number three.

The selective operation of the intake and exhaust valves for cylinder number four is also similar to the selective operation of the intake and exhaust valves for cylinder number one. Specifically, pressurized oil flows via passage or channel 581 from oil pump 580 to valve 589, which can be opened to allow oil to flow into valve body inlet 556, metering groove 551d, and valve body outlet 528a before flowing to the intake valve actuators of cylinder number four via passage 528b. Pressurized oil is also supplied to control valve body inlet 576 via a passage or line 528c. Thus, closing valve 589 can prevent deactivation of the intake and exhaust valves of cylinder number four. Outlet 512 supplies oil to accumulator 512b and the exhaust valve actuators for cylinder number four.

The 5B The intake valve actuators shown can be urged by cams 523a-529b to drive the intake valves of a cylinder bank. Specifically, cams 523a and 523b each drive two intake valves of cylinder number one. Cams 525a and 525b each drive two intake valves of cylinder number two. Cams 527a and 527b each drive two intake valves of cylinder number three. Cams 529a and 529b each drive two intake valves of cylinder number four.

Thus, the intake and exhaust valves of a cylinder bank can be individually turned on and off. Furthermore, as noted previously in some examples, oil can be supplied directly from valves 586-589 to the intake valve actuators, allowing the continuous metering grooves 551a-551d to be omitted to reduce system costs, if desired.

The oil pump 580 supplies a cooling nozzle 535 for spraying the piston 36, in 1A shown, also supplies oil via a cooling nozzle flow control valve 534. The oil pressure in the channel 581 can be regulated via a quick drain valve 532 or by adjusting the oil pump displacement actuator 533, which adjusts the displacement of the oil pump 580. The 1A The controller 12 shown may be in electrical communication with the cooling nozzle flow control valve 534, the oil pump displacement actuator 533, and the quick dump valve 532. The oil pump displacement actuator may be a solenoid valve, a linear actuator, or other known displacement actuator.

At this point, 5B which illustrates an exemplary deactivation inlet valve actuator 549 and outlet valve actuator 548 for the hydraulically operated valve deactivation system used in 5A is shown. The intake camshaft 51 rotates so that the cam 523a selectively lifts the intake follower 545, which selectively opens and closes the intake valve 52. A steering shaft 544 provides a selective mechanical linkage between the intake follower 545 and the intake valve contact member 547. A passage 546 allows pressurized oil to flow into 5C shown piston, so that the inlet valve 52 can be deactivated (e.g., remain in a closed position during an engine cycle). The intake valves 52 can be activated when the oil pressure in passage 546 is low.

Likewise, the exhaust camshaft 53 rotates so that the cam 507a selectively lifts the exhaust follower 543, which selectively opens and closes the exhaust valve 54. A steering shaft 542 provides a selective mechanical linkage between the exhaust follower 543 and an exhaust valve contact member 540. The passage 541 allows the oil to flow into 5C shown piston, so that the exhaust valve 54 can be turned on (e.g., open and closed during an engine cycle) or turned off (e.g., remain in a closed position during an engine cycle).

At this point, 5C , which shows an exemplary exhaust valve actuator 548. The intake valve actuators include similar components and operate similarly to the exhaust valve actuator. Therefore, a description of the intake valve actuators is omitted for brevity.

The exhaust follower 543 is shown with the oil passage 565 extending into the camshaft follower 564. The oil passage 565 is in fluid communication with the port 568 in the steering shaft 542. A piston 563 and a locking pin 561 selectively lock the follower 543 to the exhaust valve contact member 540, causing the exhaust valve contact member 540 to move in response to the movement of the follower 543 when oil is not acting on the piston 563. The exhaust valve driver 548 is in an on state during such conditions.

The piston 563 can be acted upon by the oil pressure within the oil passages 567 and 565. The piston 563 is moved from its inward position by high pressure oil in the passage 565, which acts against the force of a spring 569. 5C shown rest position (e.g., its normally on state) to its off state. Spring 565 pulls piston 563 into a normally locked position, which allows exhaust valve contact member 540 to drive exhaust valve 54 when the oil pressure in passage 565 is low.

The locking pin 561 stops at a position (e.g., an unlocked position) where the follower 543 is no longer locked to the exhaust valve contact member 540, thereby deactivating the exhaust valve 54 when the normally locked locking pin 561 is fully displaced by high-pressure oil acting on the piston 563. The camshaft follower 564 is steered according to the movement of the cam 507a when the exhaust valve driver 548 is in a deactivated state. The exhaust valve 54 and the exhaust valve contact member 540 remain stationary when the piston locking pin 561 is in its unlocked position.

Thus, oil pressure can be used to selectively switch the intake and exhaust valves on and off via intake and exhaust valve actuators. Specifically, the intake and exhaust valves can be switched off by allowing oil to flow to the intake and exhaust valve actuators. It is noteworthy that the intake and exhaust valve actuators can be selectively switched on and off via the 5C can be switched on and off using the mechanism shown. 5B and 5C depict the deactivating valve actuators with the steering shaft attached. Other types of deactivating valve actuators are possible and compatible with the invention, including deactivating roller rocker arms, deactivating lifters, or deactivating lash adjusters.

At this point, 5D which describes a valve and cylinder deactivation sequence for the mechanism according to 5A-5C The valve shutdown sequence can be controlled by the system after 1A and 5A-5C be provided.

The first representation from above in 5D is a plot of exhaust cam groove width versus crank angle. The vertical axis represents the exhaust cam groove width measured at the location of the oil outlet, such as passage 506 to 5A . The groove width increases in the direction of the arrow on the vertical axis. The horizontal axis represents the engine crank angle, with zero being the compression stroke at top dead center for the cylinder whose intake and exhaust grooves are shown. In this example, the exhaust groove 571a corresponds to 5A . The crank angles for the exhaust groove width correspond to the crank angle in the third illustration from the top in 5D agree.

The second illustration from the top in 5D is a plot of intake cam groove width versus crank angle. The vertical axis represents the intake camshaft groove width, and the groove width increases in the direction of the vertical axis arrow. The horizontal axis represents the crank angle of the engine, where zero is the compression stroke at top dead center for the cylinder whose intake and exhaust grooves are shown. In this example, the intake groove 551a corresponds to 5A . The crank angles for the intake groove width correspond to the crank angle in the third illustration from the top in 5D agree.

The third representation from the top in 5D is a plot of intake and exhaust valve lift versus engine crank angle. The vertical axis represents valve lift, and valve lift increases in the direction of the vertical axis arrow. The horizontal axis represents engine crank angle, and the three plots are scaled according to crank angle. The thin solid line 590 represents intake valve lift for cylinder number one when its intake valve driver is on. The thick solid line 591 represents exhaust valve lift for cylinder number one when its exhaust valve driver is on. The thin dashed lines 592 represent intake valve lift for cylinder number one when its intake valve driver is on. The thin dashed line 593 represents exhaust valve lift for cylinder number one when its exhaust valve driver is on. The vertical lines AD represent crank angles of interest for the sequence.

According to the figure, the intake valve lift for cylinder number one rises and falls before the crank angle A. An oil control valve, such as 586 after 5A , is closed before crank angle A to prevent deactivation of the intake and exhaust valves. According to the figure, the intake valve lift 590 increases before crank angle A during the intake stroke of cylinder number one. Pressurized oil sufficient to deactivate the intake valves is not present in the continuous intake camshaft groove before crank angle A.

At crank angle A, the oil control valve (e.g. 586 after 5A) opened to deactivate the intake and exhaust valves. The width of the continuous intake camshaft groove is pressurized with oil after the oil control valve is opened, allowing the intake valve drive locking pin to be moved while the camshaft lobe for the intake valve of cylinder number one is on a base circle. The exhaust crankshaft groove 571a is also pressurized with oil at crank angle A. The exhaust 506 is not pressurized with oil at angle A because the land 505a (in 5A shown) the valve body outlet 506 (in 5A shown). Therefore, only the intake valve deactivation begins at crank angle A. The intake valve actuator locking pin is released from its normal position before crank angle C to prevent the intake valve from opening.

At crank angle B, the land of exhaust camshaft journal 521a for cylinder number one makes way for discontinuous groove 571a, allowing oil to reach the exhaust valve actuator for cylinder number one. At crank angle B, oil can flow to the intake valve actuator and exhaust valve actuator; however, because the exhaust valve is partially lifted at crank angle B, the exhaust valve operates until the exhaust valve closes near crank angle C. The exhaust valve actuator lock pin is released from its normally engaged position before crank angle D to prevent the exhaust valve from opening.

At crank angle C, the intake valve does not open because the intake valve actuator is deactivated for the engine cycle. Furthermore, the exhaust valve actuator lock pin is released from its normal position before crank angle D to prevent the exhaust valve from opening. Consequently, the exhaust valve does not open for the cylinder cycle. The intake and exhaust valves can remain deactivated until the intake and exhaust actuators are reactivated by reducing the oil pressure to the intake and exhaust valve actuators.

The intake and exhaust valves can be reactivated by deactivating the oil control valve 586 and allowing the oil pressure in the intake and exhaust valve actuators to be reduced, or by quickly removing the oil pressure from the intake and exhaust valve actuators via a quick dump valve (not shown).

The oil reservoir 506b maintains the oil pressure in the oil passage 506 during the portion of the cycle after crank angle D, when the land of the exhaust cam groove blocks the passage 506. During the time when the oil supply from the pump is interrupted, the oil reservoir 506b compensates for oil leakage by varying clearances. The oil reservoir 506b may comprise a dedicated piston and a dedicated associated spring, or it can be connected to the locking mechanism such as the one in 5C mechanism shown.

At this point, 6A which shows a camshaft for an alternative hydraulically operated valve deactivation system. The camshaft 420 can be inserted into the 4A shown motor system can be integrated.

In this example, camshaft 420 may be an intake camshaft or an exhaust camshaft, or a camshaft that drives both the intake and exhaust valves. The intake and exhaust valves of each engine cylinder may be individually turned on and off. Camshaft 420 includes a drive gear 619 that allows crankshaft 40 to 1A drives the camshaft 420 via a chain. The camshaft 420 includes four journals 605a-605d having lands 606a-606d and discontinuous grooves 608a-608d. The camshaft base 602 includes stationary grooves 610a (in 6B shown) for each of the valve bodies 670a, 670b, 670c, and 670d. The stationary grooves 610a are arranged to align with the discontinuous grooves 608a-608d. The camshaft 420 also includes cams. In one example, the camshaft 420 can operate both the intake and exhaust valves as the camshaft 420 rotates. Specifically, cam 620 operates an intake valve of cylinder number one, and cam 622 operates an exhaust valve of cylinder number one. Cam 638 operates an intake valve of cylinder number two, and cam 639 operates an exhaust valve of cylinder number two. Cam 648 operates an intake valve of cylinder number three, and cam 649 operates an exhaust valve of cylinder number three. Cam 658 operates an intake valve of cylinder number four and cam 659 operates an exhaust valve of cylinder number four.

Camshaft base 602 includes valve bodies 670a, 670b, 670c, and 670d to support and provide oil passages leading to the camshaft grooves. Specifically, valve body 670a includes an inlet 613, a first outlet 612, and a second outlet 616. First outlet 612 provides oil to the exhaust valve actuators. Second outlet 616 provides oil to the intake valve actuators. Valve body 670b includes an inlet 633, a first outlet 636, and a second outlet 632. First outlet 636 provides oil to the exhaust valve actuators. Second outlet 632 provides oil to the intake valve actuators. The valve body 670c includes an inlet 643, a first outlet 646, and a second outlet 642. The first outlet 646 provides oil to the exhaust valve actuators. The second outlet 642 provides oil to the intake valve actuators. The valve body 670d includes an inlet 653, a first outlet 656, and a second outlet 652. The first outlet 656 provides oil to the exhaust valve actuators. The second outlet 652 provides oil to the intake valve actuators. The passages 616, 632, 642, and 652 supply oil to the intake valve actuators 649 (in 6C shown) via a channel or passage 692 pressurized oil from the oil pump 690 for the respective cylinder numbers 1-4 when the control valves 614, 634, 644 and 654 are switched on and open. The outlets 612, 636, 646 and 656 can be supplied to the exhaust valve actuators 648 (in 6C shown) supply oil pressure when control valves 614, 634, 644, and 654 are open. Discontinuous grooves 608a-608d selectively provide an oil path between inlets 613, 633, 643, and 653 and valve body outlets 612, 636, 646, and 656 leading to the exhaust valve actuators. Bearing journals 605a-605d are partially defined by discontinuous grooves 608a-608d. Oil reservoirs 609a-609d provide oil to keep the exhaust valves deactivated when land 606a covers passage 612 for brief periods of time.

It will now 6B , which shows a cross-section of a valve body 670a and associated components. The camshaft 420 is coupled to the camshaft base 602 via the cover cap 699. The cover cap covers the stationary groove 610a formed in the camshaft base 602. The camshaft 420 includes the discontinuous groove 608a, which is axially aligned with the stationary groove 610a. The valve 614 selectively allows oil to flow to the intake valve actuators and into the stationary groove 610a via the passage 616. The land 606a selectively covers and covers the outlet 612, which provides oil to the accumulator 609a and the exhaust valve actuators while the camshaft 420 rotates.

At this point, 6C which illustrates an exemplary deactivation inlet valve actuator 649 and deactivation outlet valve actuator 648 for the hydraulically operated valve deactivation system shown in 6A is shown. The camshaft 420 rotates so that the cam 620 selectively lifts the intake follower 645, which selectively opens and closes the intake valve 52. A steering shaft 644 provides a selective mechanical linkage between the intake follower 645 and the intake valve contact member 647. The intake valve driver 649 and the exhaust valve driver 648 include the same components. ten and work in the same way as the 5C described drive. A passage 646 allows pressurized oil to 5C illustrated piston so that the intake valve 52 can be deactivated (e.g., remain in a closed position during an engine cycle). The intake valve 52 can be activated (e.g., be open and closed during an engine cycle) when the oil pressure in the passage 646 is low.

Likewise, cam 622 rotates to selectively lift exhaust follower 643, which selectively opens and closes exhaust valve 54. A steering shaft 642 provides a selective mechanical linkage between exhaust follower 643 and an exhaust valve contact member 640. A passage 641 allows oil to flow into 5C so that the intake valve 54 can be deactivated (e.g., remain in a closed position during an engine cycle). The low oil pressure in the passage 641 activates the exhaust valve 54 (e.g., opens and closes it during an engine cycle) when the 5C shown piston 563 is returned to its normal or home position via spring 569.

In this way, a single cam can drive the intake and exhaust valves. Furthermore, the intake and exhaust valves driven by the single cam can be deactivated via the intake and exhaust valve drivers 648 and 649.

At this point, 6D which describes a valve and cylinder deactivation sequence for the mechanism according to 6A-6C The valve shutdown sequence can be controlled by the system after 1A and 6A-6C be provided.

The first representation from above in 6D is a representation of the exhaust cam groove width at the passage leading to the exhaust valve drive, relative to the crankshaft. The vertical axis represents the exhaust camshaft groove width, and the groove width increases in the direction of the vertical axis arrow. The horizontal axis represents the engine crank angle, with zero being the compression stroke at top dead center for the cylinder whose intake and exhaust grooves are represented. In this example, the exhaust groove corresponds to the width of groove 608a after 6A , measured at the oil outlet 612. The crank angles for the outlet groove width correspond to the crank angle in the third illustration from the top in 6D agree.

The second illustration from the top in 6D is a plot of intake and exhaust valve lift versus engine crank angle. The vertical axis represents valve lift, and valve lift increases in the direction of the vertical axis arrow. The horizontal axis represents engine crank angle, and the three plots are scaled according to crank angle. The thin solid line 690 represents intake valve lift for cylinder number one when its intake valve driver is on. The thick solid line 691 represents exhaust valve lift for cylinder number one when its exhaust valve driver is on. The thin dashed lines 692 represent intake valve lift for cylinder number one when its intake valve driver is on. The thin dashed line 693 represents exhaust valve lift for cylinder number one when its exhaust valve driver is on. The vertical lines AD represent crank angles of interest for the sequence.

According to the figure, the intake valve lift for cylinder number one rises and falls before the crank angle A. An oil control valve, such as 614 after 6A , is closed before crank angle A to prevent deactivation of the intake and exhaust valves. According to the figure, the intake valve lift 690 increases before crank angle A during the intake stroke of cylinder number one. Pressurized oil sufficient to deactivate the intake valves is not present in the continuous intake camshaft groove before crank angle A.

At crank angle A, the oil control valve (e.g. 614 after 6A) opened to deactivate the intake and exhaust valves. The stationary groove width (e.g. 608a after 6B) and the passage 616 are pressurized with oil after the oil control valve has been opened, so that the locking pin of the inlet valve actuator can be moved while the outlet 616 is covered by the web 606a. Thus, the outlet 616 is not pressurized with oil at angle A, since the web 606a (in 6A shown) covers the valve body outlet 616. Therefore, only intake valve deactivation begins at crank angle A. The intake valve actuator locking pin is released from its normal position before crank angle C to prevent the intake valve from opening.

At crank angle B, the land of the exhaust camshaft land 606a for cylinder number one makes way for the discontinuous groove 608a, allowing oil to reach the exhaust 616 and the exhaust valve driver for cylinder number one. At crank angle B, oil can flow to the intake valve driver and exhaust valve driver; however, because the exhaust valve is partially lifted at crank angle B, the exhaust valve operates until the exhaust valve closes near crank angle C. The exhaust valve driver lock pin is released from its normally engaged position before crank angle D to prevent the exhaust valve from opening.

At crank angle C, the intake valve does not open because the intake valve actuator is deactivated for the engine cycle. Furthermore, the exhaust valve actuator lock pin is released from its normal position before crank angle D to prevent the exhaust valve from opening. Consequently, the exhaust valve does not open for the cylinder cycle. The intake and exhaust valves can remain deactivated until the intake and exhaust actuators are reactivated by reducing the oil pressure to the intake and exhaust valve actuators.

The intake and exhaust valves can be reactivated by deactivating the oil control valve 614 and allowing the oil pressure in the intake and exhaust valve actuators to be reduced, or by quickly removing the oil pressure from the intake and exhaust valve actuators via a quick dump valve (not shown).

The oil reservoir 609a maintains the oil pressure in the oil passage 616 during the portion of the cycle after crank angle D, when the land of the exhaust cam groove blocks the passage 616. During the time when the oil supply from the pump is interrupted, the oil reservoir 609a compensates for oil leakage by varying clearances. The oil reservoir 609a may comprise a dedicated piston and spring, or it may be connected to the locking mechanism such as that shown in 5C mechanism shown.

Accordingly, the system provides the 1A-6D a vehicle system comprising: an engine; and a controller, including non-transitory executable instructions that, when executed by the controller, cause the controller to estimate a temperature in a cylinder that is deactivated and adjust a spark advance speed for the cylinder after the cylinder is reactivated in response to an indication of knock in the cylinder and based on the temperature in the cylinder, and adjust a mode in which the cylinder was previously deactivated. The vehicle system comprises where the mode in which the cylinder was previously deactivated is a mode in which air does not flow through the cylinder. The vehicle system comprises where the temperature in the cylinder when the cylinder was deactivated is based on airflow through the cylinder. The vehicle system further comprises additional instructions to reactivate the first cylinder in response to an actual total number of engine revolutions since the first cylinder was deactivated. The vehicle system includes where the advance rate is an ignition gain.

It is noteworthy that the systems 1A-6D can be operated to provide a desired engine torque where an actual total number of activated cylinders can remain the same, while the activated cylinders that make up the actual total number of activated cylinders can change from engine cycle to engine cycle. In addition, the actual total number of cylinders combusting air and fuel in an engine cycle to produce the desired engine torque can change from engine cycle to engine cycle if desired. This can be referred to as a rolling variable displacement engine. For example, a four-cylinder engine with a firing order of 1-3-4-2 can fire cylinders 1 and 3 on a first engine cycle, cylinders 3 and 2 on a subsequent engine cycle, cylinders 1-3-2 on a subsequent engine cycle, cylinders 3-4-2 on a subsequent engine cycle, and so on to provide a constant desired engine torque.

At this point, 7 which shows a method for operating an engine with deactivation cylinders and valves. The method according to 7 can be integrated into the system that is 1A-6C The method may be included as executable instructions stored in non-volatile memory. The method according to 7 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 702, method 700 determines the engine hardware configuration. In one example, the engine hardware configuration may be stored in memory at the time of manufacture. The engine hardware configuration information may include, among other things, information describing an actual total number of engine cylinders, an actual total number of engine cylinders that do not include deactivation intake and exhaust valves, an actual total number of engine cylinders that include deactivation exhaust valves, an actual total number of engine cylinders that include deactivation intake valves, identities (e.g., cylinder numbers) of cylinders that include deactivation intake valves, identities of cylinders that include deactivation exhaust valves, identities of cylinders that do not include deactivation intake and exhaust valves, engine knock sensor positions, an actual total number of engine knock sensors, and other system configuration parameters. Method 700 reads the vehicle configuration information from memory and proceeds to 704.

At 704, method 700 judges whether cylinder deactivation is available via deactivation intake and/or exhaust valves based on system configuration information retrieved at 702. If method 700 judges that cylinder deactivation is not available or possible via intake and/or exhaust valves, the answer is no, and method 700 proceeds to exit. Otherwise, the answer is yes, and method 700 proceeds to 706.

At 706, method 700 assesses whether only intake-only cylinder deactivation is available. In other words, method 700 assesses whether only the intake valves of the engine cylinders can be deactivated (e.g., kept closed for an entire engine cycle) to deactivate the cylinders while continuing to operate all exhaust valves of all engine cylinders while an engine is rotating. In some engine configurations, it may be desirable to deactivate only intake valves of the cylinders to be deactivated to reduce system cost. 2B and 2C show two examples of such an engine design. The cylinder's intake and exhaust valves may be deactivated in a closed state in which they are not opened from a closed position over an engine cycle. Method 700 may judge that only the intake valves of the engine cylinders may be deactivated to deactivate the engine cylinders, while all engine exhaust valves of the engine cylinders continue to operate when the engine is rotating, based on the hardware configuration determined at 702. If method 700 judges that only the intake valves of the engine cylinders may be deactivated to deactivate the engine cylinders, while all engine exhaust valves of the engine cylinders continue to operate when the engine is rotating, the answer is yes, and method 700 proceeds to 708. Otherwise, the answer is no, and method 700 proceeds to 710.

At 708, the method 700 determines engine cylinders whose intake valves may be deactivated and exhaust valves continue to operate when the engine is rotating. Based on the method of 8 The method may determine engine cylinders whose intake valves may be deactivated while the exhaust valves continue to operate. Method 700 proceeds to 712 after the engine cylinders whose intake valves may be deactivated are determined.

At 710, method 700 determines the engine cylinders whose intake valves and exhaust valves may be deactivated when the engine is rotating. The method may be based on the method of 10 Determine the engine cylinders whose intake and exhaust valves can be deactivated. Method 700 proceeds to 712 after all engine cylinders whose intake and exhaust valves can be deactivated have been determined.

At 712, method 700 determines the allowed or permitted cylinder modes for operating the engine. A cylinder mode determines how many engine cylinders are activated and which cylinders are activated (e.g., cylinder numbers 1, 3, and 4). Method 700 determines the allowed cylinder modes according to the method of 11 . Method 700 proceeds to 714 after the allowable cylinder modes are determined.

At 714, method 700 adjusts the engine oil pressure in response to the cylinder modes. Method 700 adjusts the engine oil pressure according to the method of 31 Method 700 proceeds to 716 after the engine oil pressure is adjusted.

At 716, method 700 deactivates the selected cylinders according to the allowed cylinder modes. Method 700 deactivates the intake and/or exhaust valves to deactivate the selected cylinders according to the allowed cylinder modes determined at 712. For example, if the engine is a four-cylinder engine and the allowed cylinder mode includes three activated cylinders, method 700 deactivates one cylinder. The respective cylinders that are activated and the cylinders that are deactivated may be based on the cylinder modes. The cylinder modes may change with vehicle operating conditions, such that an equal total actual number of cylinders may be activated and an equal total actual number of cylinders may be deactivated, but the cylinders that are activated and deactivated may change from cylinder cycle to cylinder cycle. The valve operation of deactivated cylinders is based on the cylinder deactivation mode in conjunction with the deactivated cylinder. For example, if the allowed cylinder modes include the cylinder deactivation modes from the method of 20 include, then the valves in the deactivated cylinders can be opened according to the 20 described cylinder deactivation modes.

If a plurality of actual total numbers of activated cylinders are permitted, the actual total number of activated cylinders is activated in a respective cylinder mode that provides the lowest fuel consumption while providing the desired driver demand torque. Furthermore, the permitted transmission gears associated with the enabled permitted cylinder mode may be engaged.

Method 700 may deactivate intake and/or exhaust valves via the systems described herein or via other known valve deactivation systems. If an engine knock sensor or other sensor indicates that engine noise exceeds a threshold or vibration exceeds a threshold immediately after changing cylinder modes, a different actual total number of cylinders activated and a different transmission gear may be selected (e.g., the transmission gear and cylinder mode prior to changing cylinder mode, which may be a larger actual total number of cylinders activated). The knock sensor may be interrogated at an engine crankshaft interval outside an engine knock range to prevent mode changes based on knock. Knock sensor output from within the knock range may be precluded from reactivating a cylinder in response to engine vibration.

The engine cylinders may be deactivated by holding the intake valves in closed positions throughout an engine cycle. Furthermore, fuel injection to deactivated cylinders may also be discontinued. Spark delivery to deactivated cylinders may also be discontinued. In some examples, the exhaust valves of cylinders being deactivated are also held in closed positions throughout the engine cycle while the intake valves are deactivated, thus trapping gases in the deactivated cylinders. Method 700 proceeds to 718 after select engine cylinders are deactivated via intake and exhaust valves.

At 718, method 700 regulates engine knock in response to cylinder deactivation. Method 700 regulates engine knock according to the method of 33-38 After adjusting engine knock, the process proceeds from step 700 to step 720.

At 720, method 700 performs a cylinder deactivation diagnosis. Method 700 performs the cylinder diagnosis according to the method of 39-40 Procedure 700 proceeds to the end after performing the cylinder diagnosis.

At this point, 8A which shows a method for determining cylinders whose intake valves can be deactivated. The method according to 8 can be integrated into the system that is 1A-6C The method may be included as executable instructions stored in non-volatile memory. The method according to 8 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 802, method 800 selects an actual total number of cylinders for the engine. The actual total number of cylinders may be based on vehicle mass and power requirements. In some examples, the engine will include four cylinders, while in other examples, the engine will include six or eight cylinders. Further, the actual total number of engine cylinders with valves that remain energized at all times while the engine is rotating is determined. In one example, the actual total number of cylinders, which includes valves (e.g., intake and exhaust poppet valves) that remain energized while the engine is rotating, is based on a power metric required for the vehicle to operate at a desired speed (e.g., 60 KPH). If the engine has the capacity to If the engine has the capacity to provide the power measure with two or more cylinders, the engine may be manufactured with two cylinders including valves that remain always on (e.g., open and close across an engine cycle). If the engine has the capacity to provide the power measure with four or more cylinders, the engine may be manufactured with four cylinders including valves that remain always on. The remaining cylinders are provided with deactivation intake valves and non-deactivation exhaust valves. Method 800 proceeds to 804 after the actual total number of engine cylinders and the actual total number of cylinders with valves that remain always on are determined.

At 804, the engine is constructed with non-deactivation intake valve actuators and non-deactivation exhaust valve actuators in the engine cylinders that remain activated while the engine is rotating. The remaining engine cylinders are provided with deactivation intake valve actuators and non-deactivation exhaust valve actuators. Method 800 proceeds to 806 after the engine is populated with deactivation and non-deactivation valves.

At 806, method 800 estimates an amount of oil in the cylinders with intake valves that are deactivated during an engine cycle, such that the intake valves do not open during an engine cycle or a cycle of the cylinder in which the intake valves are operating. In one example, the amount of oil in the engine cylinders is estimated based on the 8B described empirical model. Method 800 estimates the oil quantities in each engine cylinder, wherein the cylinder's intake valves are deactivated and wherein the cylinder is deactivated such that airflow through the cylinder is substantially terminated (e.g., below 10% of airflow through the cylinder during idle conditions). The oil quantity in each cylinder is rechecked at each engine cycle. Method 800 proceeds to 808 after the oil quantity in each cylinder is determined.

Additionally, at 806, method 800 may estimate the quality of the engine oil. The engine oil quality may be an estimate of the contaminants in the engine oil. The engine oil quality may be assigned a value from 0 to 100, where zero corresponds to oil at the end of its useful life and one hundred corresponds to fresh oil. In one example, the oil quality estimate is based on the engine runtime, the engine load during the runtime, and the engine speed during the runtime. For example, the average load and speed of the engine over the engine runtime may be determined. The average engine load and speed are entered into a table of empirically determined values, and the table outputs an oil quality value. It may be desirable to limit a period of time during which cylinder deactivation is available in response to oil quality, as poor oil quality may increase engine wear during cylinder deactivation and/or increase engine emissions during cylinder deactivation.

Method 800 may also determine an actual total number of particulate regenerations since a last engine oil change. A particulate filter may be regenerated by increasing the particulate filter temperature and burning the carbonaceous soot stored in the particulate filter. Each time the particulate filter is regenerated after an engine oil change, an actual total number of particulate filter regenerations increases.

At 808, method 800 prevents cylinders containing more than a limit amount of oil from being deactivated. In other words, if a cylinder with deactivated intake valves (e.g., intake valves that remain closed throughout an engine cycle) contains more than a limit amount of oil, the cylinder is reactivated (e.g., the cylinder intake and exhaust valves open and close during an engine cycle, and air and fuel are combusted within the cylinder) so that oil entry into the cylinder may be limited. The cylinder is reactivated by activating the intake valve driver and supplying spark and fuel to the cylinder. When the cylinder is reactivated, it remains activated at least until an amount of oil in the cylinder is below a limit amount. Further, the amount of temporal overlap between intake and exhaust valve opening may be increased in response to the amount of oil in the deactivated cylinder exceeding a threshold. By increasing the amount of temporal overlap between intake and exhaust valve opening in response to the amount of oil in a cylinder exceeding a threshold, it may be possible to evacuate oil vapors from the cylinder to improve the stability and emissions of a subsequent combustion event. Furthermore, a cylinder may be deactivated in response to an amount of oil in one cylinder, while a second cylinder may be deactivated during a same engine cycle, so that the total actual number of activated engine cylinders remains constant during an engine cycle. The cylinders can be turned on and off as described elsewhere herein. For example, one cylinder can be turned on by opening the intake and exhaust valves during one cycle of the one cylinder. The second cylinder can be turned off by closing the intake valves or the intake and exhaust valves and keeping them closed during one cycle of the second cylinder.

When a cylinder with deactivation intake valves and non-deactivation exhaust valves is deactivated by keeping the deactivated cylinder's intake valves closed during a deactivated cylinder cycle while the exhaust valves continue to open and close, the exhaust valve closure timing control may be adjusted in response to cylinder deactivation so that losses due to cylinder compression and expansion may be reduced. Method 800 proceeds to the end after the cylinders containing more than a threshold amount of oil are reactivated.

At 808, the cylinders may not be deactivated in response to the oil quality being below a threshold, or they may be reactivated (e.g., combusting air and fuel in the cylinders). Further, in response to an actual total number of particulate filter regenerations since a last engine oil change being above a threshold, method 800 may activate the engine cylinders or prevent the engine cylinders from deactivating. These actions may improve vehicle emissions and/or reduce engine wear.

At this point, 8B , which shows a block diagram of an exemplary empirical model for estimating the amount of oil in an engine cylinder. The amount of oil in each deactivated cylinder can be estimated using a model similar to Model 850, although the variables in the described functions or tables may have different values depending on the cylinder number.

Model 850 estimates a base amount of oil entering cylinders driving deactivated intake valves (e.g., intake valves that remain in a closed position throughout an engine or cylinder cycle) and exhaust valves at block 852. The cylinder oil amounts are determined empirically and incorporated into a table or function stored in the controller's memory. In one example, the table or function is entered by engine speed and cylinder or exhaust pressure. The table or function outputs an amount of oil in the cylinder. The oil amount is passed to block 854.

At block 854, the amount of oil in a cylinder is multiplied by a scalar or real number that adjusts the amount of oil in response to oil temperature. The viscosity of the oil may vary with oil temperature, and the amount of oil that may enter a deactivated cylinder may vary with oil temperature. Since oil viscosity may decrease with oil temperature, the amount of oil that may enter a deactivated cylinder may increase with oil temperature. In one example, block 854 includes a plurality of empirically determined scalars for various oil temperatures. The amount of oil from block 852 is multiplied by the scalar in block 854 to determine the amount of oil in the engine cylinder as a function of oil temperature.

At 856, a scalar based on the engine or cylinder compression ratio (CR) is multiplied by the output of block 854 to determine the amount of oil in the engine cylinder as a function of oil temperature and the engine compression ratio. In one example, the amount of oil in the cylinder is increased for higher cylinder compression ratios because a vacuum is created in the cylinder after the exhaust valve closes. The value of 856 is determined empirically and stored in memory.

At 858, the amount of oil in the cylinder is multiplied by a value that is a function of the exhaust valve closing position or the trapped cylinder volume. The value decreases as the timing of exhaust valve closing is retarded from the exhaust stroke at top dead center because an additional volume of exhaust gas is trapped in the cylinder as the exhaust valve closing retard increases. The value decreases as the timing of exhaust valve closing is advanced from the exhaust stroke at top dead center because an additional volume of exhaust gas is trapped in the cylinder as the exhaust valve closing advance increases. The function of 858 is determined empirically and stored in memory. The amount of oil in the cylinder is passed to block 860.

At block 860, the amount of oil in a cylinder is multiplied by a scalar that adjusts the amount of oil in response to engine temperature. Engine temperature may affect clearances between engine components, and the amount of oil entering the cylinder may vary with engine temperature and clearances between engine components. In one example, block 860 includes a plurality of empirically determined scalars for different engine temperatures. The amount of oil entering the cylinder decreases as engine temperature increases because clearances between engine components may decrease as engine temperature increases. Block 860 outputs an estimate for oil in an engine cylinder.

It will now 9 which shows an example operating sequence for a four-cylinder engine. In this example, engine cylinders number two and three can be selectively switched on and off by switching the intake valves of cylinders number two and three on and off. The four-cylinder engine has a firing order of 1-3-4-2 when combusting air and fuel. The vertical markers at time T0-T7 represent relevant times in the sequence. The representations after 9 are temporally aligned and occur simultaneously.

The first representation from above in 9 is a plot of estimated oil in cylinder number two versus time. The vertical axis represents an estimated oil quantity in cylinder number two, and the estimated oil quantity in cylinder number two increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the plot to the right side of the plot. The horizontal line 902 represents a limit for an oil quantity in cylinder number two that must not be exceeded.

The second illustration from the top in 9 is a plot of estimated oil in cylinder number three versus time. The vertical axis represents an estimated oil quantity in cylinder number three, and the estimated oil quantity in cylinder number three increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the plot to the right side of the plot. The horizontal line 904 represents a limit for an oil quantity in cylinder number three that must not be exceeded.

The third representation from the top in 9 is a representation of the number of requested working cylinders. The number of requested working cylinders can be a function of driver demand torque, engine speed, and other operating conditions. The vertical axis represents the requested number of working engine cylinders, and the requested number of working engine cylinders are shown along the vertical axis. The horizontal axis represents time, and time increases from the left side of the plot to the right side of the plot.

The fourth representation from the top in 9 is a plot of the operating state of cylinder number two versus time. The vertical axis represents the operating state of cylinder number two. Cylinder number two is operating, burning air and fuel, with the intake and exhaust valves opening and closing during an engine cycle when the trace is at a higher level near the vertical axis arrow. Cylinder number two is not operating, burning air and fuel when the trace is at a lower level near the horizontal axis. The intake valves are closed for the entire engine cycle when the trace is near the horizontal axis, and the exhaust valves open and close during an engine cycle when the trace is at the lower level near the horizontal axis arrow.

The fifth representation from the top in 9 is a plot of the operating state of cylinder number three versus time. The vertical axis represents the operating state of cylinder number three. Cylinder number three is operating, burning air and fuel, with the intake and exhaust valves opening and closing during an engine cycle when the trace is at a higher level near the vertical axis arrow. Cylinder number three is not operating, burning air and fuel when the trace is at a lower level near the horizontal axis. The intake valves are closed for the entire engine cycle when the trace is near the horizontal axis, and the exhaust valves open and close during an engine cycle when the trace is at the lower level near the horizontal axis arrow.

At time T0, the estimated oil quantity in cylinder number two is low. The estimated oil quantity in cylinder number three is also low. The engine is operating with four cylinders on. (e.g., cylinders burning air and fuel), indicated by the requested number of cylinders being four and the operating states of cylinders two and three being on (e.g., the cylinder operating state traces are at higher levels). Cylinders one and four are always on when the engine is running and burning air and fuel.

At time T1, the estimated oil quantities in cylinders two and three are low. The number of requested operating cylinders is reduced from four to three. The requested number of engine cylinders may be reduced in response to lower driver demand torque. Cylinder three is deactivated in response to the requested number of cylinders being three (e.g., combustion in cylinder three is halted, the intake valves of cylinder three are deactivated so they do not open and close during an engine cycle, fuel delivery to the cylinder is stopped, spark delivery to the cylinder may be stopped, and the exhaust valves of cylinder three continue to open and close during each engine cycle). Cylinder two continues to operate with intake valves and combustion on.

Between time T1 and time T2, the estimated oil quantity in cylinder number two remains low and constant. The estimated oil quantity in cylinder number three increases. The oil quantity in cylinder number three increases because a vacuum can form in cylinder number three after the exhaust valves of cylinder number three close, since the intake valves of cylinder number three are deactivated.

At time T2, the amount of oil in cylinder number three equals or exceeds threshold 904. Therefore, cylinder number three is re-enabled, which increases the pressure in the cylinder and forces oil out of the cylinder past the cylinder rings, thereby reducing the amount of oil in cylinder number three. However, because the requested number of cylinders is three, cylinder number two is deactivated (e.g., combustion in cylinder number two is halted, the intake valves of cylinder number two are deactivated so they do not open and close during an engine cycle, fuel delivery to the cylinder is stopped, spark delivery to the cylinder can be stopped, and the exhaust valves of cylinder number two open and close during each engine cycle). Thus, the requested number of operating cylinders is provided even if the amount of oil in one cylinder is at or above a threshold. The estimated amount of oil in cylinder number two is at a lower level. The operating state of cylinder number two is low to indicate that cylinder number two is deactivated. The operating state of cylinder number three is high to indicate that cylinder number three is on.

At time T3, the number of requested working cylinders is two, and the estimated oil quantity in cylinder number two is low. Cylinder number three is deactivated in response to the low oil quantity in cylinder number three and the number of requested working cylinders. Cylinder number two remains in a deactivated state. The oil quantity in cylinder number two continues to increase.

At time T4, the oil quantity in cylinder number two exceeds threshold level 902, and the number of requested operating cylinders is two. Cylinder number two is reactivated to evacuate oil from cylinder number two. Cylinder number three remains deactivated, so the number of combusting cylinders is close to the requested number of operating cylinders. Shortly after time T4, cylinder number two is reactivated in response to the estimated oil quantity in cylinder number two being low.

At time T5, the oil quantity in cylinder number three exceeds threshold level 904, and the number of requested operating cylinders is two. Cylinder number three is reactivated to evacuate oil from cylinder number three. Cylinder number two remains deactivated, so the number of combusting cylinders is close to the requested number of operating cylinders. Shortly after time T5, cylinder number three is reactivated in response to the estimated oil quantity in cylinder number three being low.

At time T6, the oil quantity in cylinder number two exceeds the threshold level 902, and the number of requested working cylinders is two. Cylinder number two is reactivated to evacuate oil from cylinder number two. Cylinder number three remains deactivated, so the number of burning cylinders is close to the requested number of working cylinders. Shortly after At time T6, cylinder number two is reactivated in response to the estimated oil quantity in cylinder number two being low.

At time T7, the requested number of operating cylinders is increased in response to an increase in driver demand torque. The operating states of cylinders two and three transition to on to indicate that cylinders two and three have been reactivated in response to the number of operating cylinders. The estimated oil quantity in cylinders two and three is reduced by activating cylinders two and three.

For example, engine cylinders can be selectively deactivated and activated to save fuel and reduce oil in the engine cylinders. Furthermore, the activated cylinders can be deactivated to reduce oil in the engine cylinders and attempt to match the requested number of operating cylinders. Activating cylinders to remove oil from the cylinders takes priority over deactivating cylinders to match the requested number of operating cylinders, thus reducing oil consumption.

At this point, 10 which shows a method for determining cylinders whose intake valves can be deactivated. The method according to 10 can be integrated into the system that is 1A-6C The method may be included as executable instructions stored in non-volatile memory. The method according to 10 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1002, method 1000 selects an actual total number of cylinders for the engine. The actual total number of cylinders may be based on vehicle mass and power requirements. In some examples, the engine will include four cylinders, while in other examples, the engine will include six or eight cylinders. Further, the actual total number of engine cylinders with valves that remain energized at all times while the engine is rotating is determined. In one example, the actual total number of cylinders, which includes valves (e.g., intake and exhaust poppet valves) that remain energized while the engine is rotating, is based on a power rating required for the vehicle to operate at a desired speed (e.g., 60 KPH). If the engine has the capacity to provide the power rating with four or more cylinders, the engine may be manufactured with four cylinders including valves that remain energized at all times (e.g., open and close throughout an engine cycle). If the engine has the capacity to provide the power measure with six or more cylinders, the engine may be manufactured with six cylinders including valves that remain always on. The remaining cylinders are provided with deactivation intake valves and non-deactivation exhaust valves. Method 1000 proceeds to 1004 after determining the actual total number of engine cylinders and the actual total number of cylinders with valves that remain always on.

At 1004, the engine is constructed with non-deactivation intake valve actuators and non-deactivation exhaust valve actuators in the engine cylinders that remain activated while the engine is rotating. The remaining engine cylinders are provided with deactivation intake valve actuators and deactivation exhaust valve actuators. Method 1000 proceeds to 1006 after the engine is populated with deactivation and non-deactivation valves.

At 1006, method 1000 estimates an amount of oil in the cylinders with intake valves that are deactivated during an engine cycle, such that the intake valves do not open during an engine cycle or a cycle of the cylinder in which the intake valves are operating. In one example, the amount of oil in the engine cylinders is estimated based on the 8B described empirical model; however, the results in 8B described functions and/or tables may include different variable values than those for an engine with cylinders deactivated via intake valve closure alone over an engine cycle. Method 1000 estimates the amounts of oil in each engine cylinder with the cylinder's intake valves deactivated and with the cylinder deactivated such that airflow through the cylinder is substantially eliminated (e.g., below 10% of airflow through the cylinder during idle conditions). The amount of oil in each cylinder is rechecked at each engine cycle. Method 1000 proceeds to 1008 after the amount of oil in each cylinder is determined.

At 1008, method 1000 prevents cylinders containing more than a limit amount of oil from being deactivated. In other words, if a cylinder with both intake and exhaust valves deactivated len (e.g., intake and exhaust valves that remain closed throughout an engine cycle) contain more than a limit amount of oil, the cylinder is re-enabled (e.g., the cylinder intake and exhaust valves open and close during an engine cycle and air and fuel are combusted in the cylinder) so that oil entry into the cylinder can be limited. The cylinder is re-enabled by energizing the intake valve driver and supplying spark and fuel to the cylinder. Method 1000 proceeds to exit after the cylinders containing more than a limit amount of oil are re-enabled.

At this point, 11 which shows a method for determining available cylinder modes for an engine. The method according to 11 can be integrated into the system that is 1A-6C The method may be included as executable instructions stored in non-volatile memory. The method according to 11 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1102, method 1100 evaluates the engine cylinder mode activity against thresholds to determine whether changing cylinder modes represents too much activity or is appropriate. If the cylinder mode is changed too frequently, vehicle occupants may become aware of the cylinder mode switching, making the cylinder mode switching undesirable. Method 1100 evaluates the cylinder mode switching according to the method of 12 and goes to 1106.

At 1106, method 1100 evaluates which cylinder modes can provide a requested amount of engine braking torque. Method 1100 proceeds to the method of 14 to determine which cylinder modes can provide the requested amount of engine braking torque. Method 1100 proceeds to 1108 after determining which cylinder modes can provide the requested amount of braking torque.

At 1108, method 1100 evaluates whether changing the cylinder mode will reduce fuel consumption. Method 11 proceeds to the method of 15 to determine whether changing the cylinder mode can save fuel. Method 1100 proceeds to 1112 after determining whether changing the cylinder mode will save fuel.

At 1112, method 1100 evaluates a cam phase control rate to determine the cylinder mode. The cam phase control rate is a rate at which a cam torque actuated pointer changes a position of an engine's cam relative to a position of the engine's crankshaft. Because cam torque actuated variable valve timing phase actuators rely on valve spring force for operation, and because deactivating a cylinder's valves reduces the reaction force provided by the valve springs, the use of some cylinder modes may not be desirable when high rates of cam phase change are desired. Method 1100 evaluates the cam phase rate for available cylinder modes according to the method of 16 and then goes to 1114.

At 1114, method 1100 evaluates different transmission gears to select the cylinder mode. Method 1100 evaluates different transmission gears to select the cylinder mode according to the method of 18 . Method 1100 proceeds to 1116 after different transmission gears are evaluated for selecting the cylinder mode.

At 1116, method 1100 evaluates tow and pull modes to select the cylinder mode. Method 1100 evaluates the tow and pull modes to select the cylinder mode according to the method of 20 . Method 1100 proceeds to 1118 after the tow and pull modes are evaluated to select the cylinder mode.

At 1118, method 1100 assesses whether selected conditions for selecting the cylinder mode exist. Method 1100 determines whether conditions for determining the cylinder mode exist according to the method of 22 Method 1100 proceeds to 1120 after determining whether conditions exist for selecting the cylinder mode.

At 1120, method 1100 regulates the engine intake manifold absolute pressure (MAP) during conditions where one or more cylinders are deactivated via deactivation of the intake and/or exhaust valves of the engine cylinders. Furthermore, fueling to the cylinder and spark delivery to the cylinder is terminated when the cylinder is deactivated. Method 1100 regulates the MAP according to the method of 23 and goes to 1121.

At 1121, method 1100 regulates the absolute engine manifold pressure (MAP) during conditions where one or more cylinders are activated via activation of the intake and/or exhaust valves of the engine cylinders. Furthermore, fueling to the cylinder and spark delivery to the cylinder are activated when the cylinder is activated. Method 1100 regulates the MAP according to the method of 25 and goes to 1122.

At 1122, method 1100 regulates engine torque during the cylinder mode change. Method 1100 regulates engine torque according to the method of 27A before moving on to 1124.

At 1124, method 1100 regulates the fuel supplied to the engine to change cylinder modes. Method 1100 regulates the fuel supplied to the engine according to the method of 29 . Method 1100 proceeds to end after the fuel flow to the engine has been regulated.

At this point, 12 which shows a method for evaluating whether or not changing the cylinder mode exceeds activity limits. The method according to 12 can be integrated into the system that is 1A-6C The procedure according to 12 may be contained as executable instructions stored in non-volatile memory. The method according to 12 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1202, method 1200 judges whether the present execution of method 1200 is a first execution of method 1200 since the vehicle and engine were stopped and turned off. Method 1200 may judge that the present execution of method 1200 is a first execution since the vehicle was turned on after the vehicle was turned off (e.g., stopped without an immediate intention to restart). In one example, method 1200 judges that the present execution is a first execution if a value in memory is zero and the method has not been executed since a driver requested the vehicle to start via a push button or key. If method 1200 judges that the present execution of method 1200 is a first execution of method 1200 since the engine was stopped, the answer is yes and method 1200 proceeds to 1220. Otherwise, the answer is no and method 1200 proceeds to 1204.

At 1220, method 1200 determines values for the variables PAYBACK TIME and VDE_BUSY. The variable PAYBACK TIME is a period of time required in a newly selected cylinder mode or variable displacement (VDE) engine mode to cover the fuel costs of switching from one cylinder mode or VDE mode to the next cylinder mode or VDE mode. The fuel costs may be due to reducing engine torque via spark retard or another setting used to regulate engine torque during mode switches. The variable VDE_BUSY is a value that is a basis for determining whether or not cylinder mode or VDE switching is occurring at a higher than desired frequency. The value is updated based on the number of cylinder mode or VDE switches and the period of time spent in a cylinder mode or VDE mode. VDE_BUSY is initially set to zero, and PAYBACK TIME is empirically determined and stored in memory. In one example, the PAYBACK TIME variable can vary depending on the cylinder mode being exited and the cylinder mode being activated. There can be VDE_BUSY variables for each cylinder mode, as shown in 13 shown. The method 1200 proceeds to 1204 after the variable values have been determined.

At 1204, method 1200 judges whether the engine exits a valve deactivation mode. Method 1200 may judge that the engine exits a valve deactivation mode when valves of one or more cylinders are turned on in an engine cycle (e.g., when intake valves transition from not opening and closing during an engine cycle to opening and closing during an engine cycle). If method 1200 judges that the engine exits a valve deactivation mode and valves of at least one cylinder are turned on again during an engine cycle, switched, the answer is Yes and procedure 1200 proceeds to 1208. Otherwise the answer is No and procedure 1200 proceeds to 1230.

At 1230, method 1200 judges whether the engine is operating in a valve deactivation mode. Method 1200 may judge that the engine is operating in a valve deactivation mode if the intake and/or exhaust valves of an engine cylinder remain closed and do not open and close during an engine cycle. If method 1200 judges that the engine is operating in a valve deactivation mode, the answer is yes and method 1200 proceeds to 1232. Otherwise, the answer is no and method 1200 proceeds to 1210.

At 1232, method 1200 counts a measure of time during which one or more cylinders have valves in a deactivated state to determine a period of time during which the engine is in a deactivated mode. The engine may have more than one deactivated mode, and the time in each deactivated mode may be determined. For example, an eight-cylinder engine may deactivate two cylinders or four cylinders to provide two deactivated modes. The first deactivated mode is when two cylinders are deactivated, and the second deactivated mode is when four cylinders are deactivated. Method 1200 determines the period of time during which the engine has two deactivated cylinders and the period of time during which the engine has four deactivated cylinders. Method 1200 proceeds to 1210 after determining a period of time during which one or more engine cylinders are in a deactivated mode.

At 1208, method 1200 determines a period of time to add or subtract from the VDE_OFF-LOADED variable based on a period of time during which one or more cylinders have deactivated valves and the PAYBACK TIME. A larger number is added to the VDE_OFF-LOADED variable if the engine has deactivated cylinders in a mode for a short period of time relative to the PAYBACK TIME. For example, if an eight-cylinder engine operates with valves on in four cylinders for four seconds, method 1200 may add a value of 120 to the VDE_OFF-LOADED variable if the PAYBACK TIME variable is 20. On the other hand, if an eight-cylinder engine operates for 19 seconds with valves on in four cylinders, method 1200 may add a value of 40 to the VDE_OFFLOADED variable when the PAYBACK TIME variable is 20. If the eight-cylinder engine operates for 45 seconds with valves on in four cylinders, method 1200 may add a value of -10 to the VDE_OFFLOADED variable when the PAYBACK TIME variable is 20. The value added to VDE_OFFLOADED may be a linear or non-linear function of the difference between the amount of time the engine spends in cylinder deactivation mode and the value of PAYBACK TIME. Method 1200 proceeds to 1210 after setting the value of VDE_OFFLOADED.

At 1210, method 1200 subtracts a predetermined amount or value from the VDE_BUSY variable. For example, method 1210 may subtract a value of 5 from the VDE_BUSY variable. Subtracting a predetermined amount from the VDE_BUSY variable may drive the VDE_BUSY variable toward a value of zero. The VDE_BUSY variable is constrained to positive values greater than zero. Method 1200 proceeds to 1212 after the predetermined amount is subtracted from the VDE_BUSY variable.

At 1212, method 1200 judges whether cylinder valve deactivation is requested to reduce the number of activated cylinders. Cylinder valve deactivation may be requested in response to lower driver demand torque or other driving conditions. If method 1200 judges that cylinder valve deactivation is requested by the present cylinder mode or VDE mode, the answer is yes and method 1200 proceeds to 1214. Otherwise, the answer is no and method 1200 proceeds to 1240.

At 1240, method 1200 assesses whether cylinder valve reactivation is requested to increase the number of activated cylinders (e.g., if the intake valves of two cylinders are requested to be reactivated in response to an increase in driver demand torque). Cylinder valves may be reactivated to reactivate a cylinder valve. The cylinder may be reactivated in response to an increase in driver demand torque or another condition. If method 1200 assesses that cylinder valve reactivation is requested is, the answer is yes and procedure 1200 proceeds to 1244. Otherwise the answer is no and procedure 1200 proceeds to 1242.

At 1244, the procedure 1200 allows the reactivation of deactivated cylinder valves and cylinders. The cylinder valves can be activated via the 6A and 6B shown or other known mechanisms. After allowing the re-energization of deactivated cylinder valves, method 1200 proceeds to the end. The valves may be deactivated according to the method of 22 be switched on.

At 1242, method 1200 does not allow any number of cylinder valves to be turned on or off other than those currently turned on or off. In other words, the current value of the number of valves and cylinders turned on is maintained. After maintaining the current number of cylinders turned on and off, method 1200 proceeds to exit.

At 1214, method 1200 judges whether a period of time since a cylinder valve re-energization request is greater than the value of the variable VDE_OFFBUSY. If so, the answer is yes and method 1200 proceeds to 1216. Otherwise, the answer is no and method 1200 proceeds to 1242. In this manner, cylinder valve deactivation can be delayed until a period of time between a cylinder mode or VDE mode change is greater than the value of VDE_OFFBUSY, which increases as the cylinder valve deactivation frequency increases and decreases as the cylinder valve deactivation frequency decreases.

At 1216, method 1200 allows deactivation of selected cylinder valves to deactivate selected cylinders. Deactivation of fuel supplied to the cylinders and termination of spark delivery to the cylinders may also be permitted. The valves may be deactivated according to the method of 22 be switched off.

At this point, 13 in which an engine operating sequence according to the procedure according to 12 The vertical lines at time points T1300-T1314 represent relevant time points in the sequence. 13 shows six representations, and the representations are time-aligned and occur simultaneously. In this example, deactivating a cylinder means deactivating at least the intake valves of the cylinder being deactivated such that the deactivated intake valves remain in closed states throughout an engine cycle. In some examples, the exhaust valves of deactivated cylinders are also deactivated such that the exhaust valves remain in a closed state throughout a cycle of the engine. Spark and fuel are not delivered to deactivated cylinders, so no combustion occurs in deactivated cylinders. Alternatively, cylinder deactivation may include ceasing combustion and fuel injection to a cylinder while the cylinder's valves continue to operate.

The first representation from above in 13 is a plot of cylinder deactivation request versus time. Engine cylinders can be deactivated in response to the cylinder deactivation request. The vertical axis represents the cylinder deactivation request, and the horizontal axis represents time. Time increases from the left side of the figure to the right side of the figure. In this example, the engine is an eight-cylinder engine and can operate with four, six, or eight cylinders activated. The numbers on the vertical axis indicate which cylinders are requested or not requested for deactivation. For example, if the trace is at level eight, no cylinders are requested for deactivation. If the trace is at level six, two cylinders are requested for deactivation. Four cylinders are requested for deactivation if the trace is at level four. A cylinder deactivation request can be based on driver demand torque or other vehicle conditions. In some examples, only the intake valves of a cylinder are deactivated to deactivate a cylinder. In other examples, the intake and exhaust valves are deactivated to deactivate a cylinder. When a cylinder is deactivated, spark delivery and fuel flow to that cylinder cease.

The first representation from above in 13 is a plot of cylinder activation state versus time. The cylinder activation state provides the actual operating state of engine cylinders. The vertical axis represents the cylinder activation state, and the horizontal axis represents time. The numbers on the vertical axis indicate which cylinders are activated. For example, if the trace is at level eight, all cylinders are on. If the trace is at level six, six cylinders are on. Four cylinders are on if the trace is at level four. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

In the third illustration from the top in 13 This is a representation of the amount of time the engine is in the first cylinder mode, in this example, six-cylinder operation. The vertical axis represents the period in the first cylinder mode, and the time in the first cylinder mode increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

In the fourth illustration from the top in 13 This is a representation of the amount of time the engine is in the second cylinder mode, in this example, four-cylinder operation. The vertical axis represents the period in the second cylinder mode, and the time in the second cylinder mode increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 13 is a plot of the value of the VDE_BUSY variable for the first cylinder valve deactivation mode, in this example, six-cylinder operation. The vertical axis represents the value of the VDE_BUSY variable in the first cylinder mode. This value corresponds to a period of time that must elapse after a request to activate the first cylinder mode is made before the first cylinder mode can be activated. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 13 is a representation of the value of the VDE_BUSY variable for the second cylinder mode, in this example, four-cylinder operation. The vertical axis represents the value of the VDE_BUSY variable in the second cylinder mode. This value corresponds to a period of time that must elapse after a request to activate the second cylinder mode is made before the second cylinder mode can be activated. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T1300, the engine is operating with all valves and cylinders energized, indicated by a cylinder energization state value of eight. The cylinder energization request does not request deactivation of any valves or cylinders, and the time period in the first and second cylinder modes is zero. The VDE_BUSY variable for the first cylinder mode, which deactivates cylinders, is zero. The VDE_BUSY variable for the second cylinder mode, which deactivates cylinders, is also zero.

At time T1301, the cylinder deactivation request changes state to request deactivation of the valves of two cylinders, so the eight-cylinder engine operates with six cylinders on. The cylinder deactivation state changes state to indicate that the engine is operating with six cylinders on and with two cylinders deactivated. Time accumulates in the first cylinder mode because the engine is in the first cylinder mode (e.g., operating with six cylinders on). Time does not accumulate in the second cylinder mode because the engine is not operating in the second cylinder mode (e.g., operating with four cylinders on). The variables VDE_OFF for the first cylinder mode and VDE_OFF for the second cylinder mode are zero because the engine has not exited the first or second cylinder mode.

At time T1302, the cylinder deactivation request changes state to request no cylinder valves be deactivated, so the engine is operating as an eight-cylinder engine. The cylinder deactivation state changes state to indicate that the engine is operating with eight cylinders activated and no valves deactivated. Time accumulation in the first cylinder mode ends because the engine is operating with all cylinder valves and as an eight-cylinder engine. No time accumulates in the second cylinder mode because the engine is not operating in the second cylinder mode. The VDE_OFF value for the first cylinder mode increments based on the amount of time the engine has been in the first cylinder mode.

At time T1303, the cylinder deactivation request changes state again to request deactivation of the valves of two cylinders, so the eight-cylinder engine operates with six cylinders on. The cylinder deactivation state does not change state because the VDE_OFFSET value for the first cylinder mode is greater than the PAYBACK TIME variable (not shown). The VDE_OFFSET value for the first cylinder mode decreases because a predetermined period of time is subtracted from the first cylinder mode VDE_OFFSET each time the procedure is executed. No time accumulates in the second cylinder mode because the engine is not operating in the second cylinder mode (e.g., operating with four cylinders on). VDE_OFFSET for the second cylinder mode is zero because the engine has not exited the second cylinder mode.

At time T1304, the VDE_OFFSET value for the first cylinder mode is equal to or less than the value for the PAYBACK TIME variable, thus deactivating the cylinder valves to provide six-cylinder operation, as indicated by the cylinder activation state transitioning to the level indicating six-cylinder engine operation. The time period in the first cylinder mode begins to increase. The time period in the second cylinder mode remains at zero. The VDE_OFFSET value for the first cylinder valve deactivation mode continues to decrease, and the VDE_OFFSET value for the second cylinder valve deactivation mode remains at zero.

At time T1305, the cylinder deactivation request transitions to a value of eight. The cylinder activation state also transitions to a value of eight based on the cylinder deactivation request. The time in the first cylinder mode is short, causing the VDE_OFF value for the first cylinder mode to increase by a large amount. The VDE_OFF value for the second cylinder mode is zero because the engine has not been in the second cylinder mode. Shortly thereafter, the cylinder deactivation request transitions to a value of six to request the deactivation of valves in two engine cylinders, allowing the engine to operate as a six-cylinder engine combusting air-fuel mixtures in six of eight cylinders. However, the engine does not transition to six-cylinder operation, as indicated by the cylinder activation state maintaining a value of eight. The engine does not switch to six-cylinder mode and deactivates the valves of two cylinders because the value for VDE_OFFLOADED for the first cylinder mode is greater than the value for the variable PAYBACK TIME (not shown).

At time T1306, the engine transitions to six-cylinder mode, in which the cylinder valves in two engine cylinders are deactivated to deactivate two cylinders. Fuel and spark are not provided to the two deactivated cylinders. The cylinder activation state transitions to a value of six to indicate that the engine is operating in six-cylinder mode with the cylinder valves deactivated in two cylinders. The period in the first cylinder mode begins to increase. The period in the second cylinder mode remains at zero. The VDE_OFF-LOADED value for the first cylinder mode continues to decrease, and the VDE_OFF-LOADED value for the second cylinder mode remains at zero.

At time T1307, the cylinder deactivation request transitions to eight to request eight cylinders on. The period of time the engine operates in the first cylinder mode is long, correcting the VDE_OFF-LOADED value for the first mode to a low value. The cylinder activation state transitions to a value of eight to indicate that the engine has all eight cylinders and valves on. The period of time in the second cylinder mode is zero, and the VDE_OFF-LOADED value for the second cylinder mode is zero.

At time T1308, the cylinder deactivation request transitions to a value of six in response to a reduced driver demand torque (not shown). At almost the same time, the cylinder activation state also transitions to a value of six based on the cylinder deactivation request. The period in the first cylinder mode begins to increase, and the period in the second cylinder mode remains at zero. The VDE_OFF values for the first and second valve deactivation modes are zero.

At time T1309, the cylinder deactivation request transitions to a value of four in response to the driver demand torque (not shown). The cylinder activation state also transitions to a value of four in response to the cylinder deactivation request value. The time in the first cylinder mode transitions to zero, and the VDE_OFF-LOADED value for the first cylinder mode is set to zero. The time in the second cylinder mode begins to increase, and the VDE_OFF-LOADED value for the second cylinder valve deactivation mode remains at a value of zero.

At time T1310, the cylinder valve deactivation request transitions back to a value of six in response to the driver demand torque (not shown) increasing. The cylinder activation state transitions back to a value of six in response to the cylinder deactivation request. The VDE_OFF value for the second cylinder valve deactivation mode is increased in response to the brief period of time the engine is operating in four-cylinder mode. The period in the first cylinder mode begins to increase, and the period in the second cylinder mode is set to zero.

At time T1311, the cylinder deactivation request transitions back to a value of four in response to the driver demand torque (not shown) decreasing. The cylinder activation state remains at a value of six because the VDE_OFFSET value for the second cylinder mode is greater than the value of the PAYBACK TIME variable (not shown). The time in the first cylinder mode continues to increase, and the time in the second cylinder mode remains at zero. The VDE_OFFSET value for the first cylinder valve deactivation mode remains at zero.

At time T1312, the cylinder deactivation request transitions back to a value of six in response to the driver demand torque (not shown) increasing. The cylinder activation state is at a value of six based on the cylinder deactivation request value. The time in the first cylinder mode continues to increase, and the time in the second cylinder mode is zero. The VDE_OFF value for the second cylinder mode continues to decrease because the engine has not transitioned out of the second cylinder mode.

At time T1313, the cylinder deactivation request transitions to a value of four in response to the driver demand torque (not shown) decreasing. The cylinder activation state remains at a value of six because the VDE_OFFSET value for the second cylinder mode is greater than the value of the PAYBACK TIME variable (not shown). Therefore, the valves of two cylinders are deactivated even though the cylinder deactivation request is at a value of four. The time in the first cylinder mode continues to increase, and the time in the second cylinder mode remains at zero. The VDE_OFFSET value for the first cylinder mode remains at zero.

At time T1314, the cylinder deactivation request remains at a value of four, and the cylinder activation state transitions to a value of four in response to the amortization time value (not shown). Therefore, the valves of four cylinders are deactivated and four cylinders are activated. The time in the first cylinder mode transitions to zero, and the VDE_OFF-LOADED value for the first cylinder mode is set to zero. The time in the second cylinder mode begins to increase, and the VDE_OFF-LOADED value for the second cylinder mode continues to decrease.

At time T1315, the cylinder deactivation request transitions to a value of eight to request the activation of all cylinder valves and cylinders. The cylinder activation state transitions to a value of eight to indicate that all cylinder valves and cylinders are activated. The duration in the second cylinder mode is long, which sets the VDE_BUSY value for the second valve mode low, allowing a smooth transition to the four-cylinder mode in which the cylinder valves of four cylinders are activated.

Therefore, it can be observed that the activation of the different cylinder modes can be prevented based on the amount of time spent in a cylinder mode relative to a payback period. Furthermore, the cylinder modes are not locked in response to cylinder mode switching activity. Instead, the activation of the different cylinder modes can be delayed for varying periods of time to reduce a driver's perception of cylinder mode switching activity.

At this point, 14 which shows a method for evaluating engine braking torque in available cylinder modes as a basis for selectively allowing cylinder deactivation. The method according to 14 can be integrated into the system that is 1A-6C The procedure according to 14 may be contained as executable instructions stored in non-volatile memory. The method according to 14 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1402, method 1400 determines a desired engine torque and a current engine speed. The engine speed may be determined via an engine position or speed sensor. A period of time it takes for an engine to move between two positions is the engine speed. The desired engine torque may be determined from a driver demand torque. In one example, the driver demand torque is based on the accelerator pedal position and the vehicle speed. The accelerator pedal position and vehicle speed are entered into a table of empirically determined values for the driver demand torque. The value for the driver demand torque corresponds to a desired torque at a position along the driveline. The position along the driveline may be the engine crankshaft, the transmission input shaft, the transmission output shaft, or the vehicle wheel. If the driver demand torque is an engine torque, the output from the table is the desired or requested engine torque. Torques at other points along the driveline can be determined by setting a desired torque at one point based on gear ratios, torque multiplication devices, losses, and torque capacities of clutches.

For example, if a driver demand torque is wheel torque, the engine torque may be determined by multiplying the driver demand torque (or the desired wheel torque) by the gear ratios between the wheel and the engine. If the powertrain includes a torque converter, the desired wheel torque may be further divided by the torque converter's torque multiplication factor to determine the engine torque. Torque transmitted through clutches may be estimated as a multiplier. For example, if a clutch is not slipping, the torque input to the clutch equals the torque output from the clutch, and the multiplier value is one. The torque input to the clutch multiplied by one equals the torque output from the clutch. If the clutch is slipping, the multiplier is a value from 0 to a number less than one. The multiplier value may be based on the torque capacity of the clutch. Method 1400 proceeds to 1404.

At 1404, method 1400 determines cylinder modes that can provide the desired engine torque. In one example, an engine torque table may be provided that describes the maximum engine torque output as a function of cylinder mode and engine speed. The desired engine torque is compared to the engine cylinder valve timing and the atmospheric pressure compensated outputs from the engine torque table, which is maintained after the cylinder mode at the current engine speed, current atmospheric pressure, and current cylinder valve timing (e.g., intake valve closure timing). If the engine torque table outputs a torque value that is greater than the desired engine torque plus an offset torque, it may be determined that the cylinder mode corresponding to the torque output from the table is a cylinder mode that provides the desired engine torque. The values stored in the engine torque table may be empirically determined and stored in the controller's memory.

An example of an engine braking torque table is shown in 1 This is an engine torque table for a four-cylinder engine. The engine torque table can include torque output values for three cylinder modes: a two-cylinder on mode, a three-cylinder on mode, and a four-cylinder on mode. The engine torque table can also include a variety of engine speeds. The torque values between the engine speeds can be interpolated. Table 1: Table 1. Engine speed Cylinders switched on 500 1000 2000 3000 4000 2 39 48 52 49 43 3 58 74 79 76 65 4 77 96 104 100 88

Thus, Table 1 contains rows with the activated cylinder modes and columns with the engine speed. In this example, Table 1 outputs the torque values in units of Nm. The engine braking torque values output from the braking torque table may be calculated using functions based on ignition timing from minimum spark for best torque (MBT); intake valve closing from a nominal intake valve closing time, engine air-fuel ratio, and engine temperature. The functions output empirically determined multipliers that modify the engine braking torque value output from the engine braking torque table. The desired engine braking torque is compared to the modified value output from the engine braking torque table. Note that the desired wheel torque may be converted to a desired engine torque by multiplying the desired wheel torque by the gear ratio between the wheels and the engine. Further, determining the engine torque may include modifying the wheel torque according to the torque multiplication of the transmission torque converter. Additionally or alternatively, cylinder modes, which include different firing orders or activated cylinders in an engine cycle, may also be a basis for entering and storing values in an engine braking torque table. Method 1400 proceeds to 1406.

At 1406, the method allows 1400 cylinder modes that can provide the desired engine torque to be allowed. The allowed cylinder modes can be 7 be switched on.

An example using Table 1: Table 1 is populated by engine speed and cylinder mode. The cylinder mode starts at a minimum value, in this example two, and is incremented until it reaches the maximum cylinder mode. For example, if the engine is operating at 1000 RPM and the desired engine torque is 54 N-m, Table 1 will output a value of 48 N-m, which corresponds to 1000 RPM and cylinder mode two (e.g., two cylinders activated), 74 N-m, which corresponds to 1000 RPM and cylinder mode three (e.g., three cylinders activated), and 96 N-m, which corresponds to 1000 RPM and cylinder mode four (e.g., four cylinders activated). The cylinder mode with two cylinders activated at 1000 RPM is not allowed because two cylinders activated lack the capacity to provide the desired 74 N-m of torque. Three- and four-cylinder cylinder modes are permitted. In some examples, the desired engine torque plus a specified offset is compared to values output from the table. If the desired engine torque plus the specified offset is greater than an output from the table, the cylinder mode corresponding to the table output is disallowed. Allowed and disallowed cylinder modes can be specified by variable values stored in memory. For example, if three-cylinder mode is permitted at 1000 RPM, a variable in memory corresponding to three-cylinder mode at 1000 RPM can be set to a value of one. If cylinder mode three is disallowed at 500 RPM, a variable in memory corresponding to cylinder mode three at 500 RPM can be set to a value of zero. Method 1400 proceeds to exit.

Therefore, the engine cylinder modes and the engine braking torque available in the cylinder modes can be used to determine which cylinder mode the engine operates in. Furthermore, cylinder modes with lower fuel consumption can be given selection priority, thus saving fuel.

At this point, 15 which shows a method for evaluating engine fuel consumption in available cylinder modes as a basis for selectively allowing cylinder deactivation. The method according to 15 can be integrated into the system that is 1A-6C The procedure according to 15 may be contained as executable instructions stored in non-volatile memory. The method according to 15 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1502, method 1500 determines a desired engine torque and a current engine speed. The engine speed may be determined via an engine position or speed sensor. Method 1500 proceeds to 1504.

At 1504, the method 1500 determines cylinder modes that can provide the desired engine torque. In one example, the cylinder modes that can provide the desired engine torque are as shown in 14 described.

At 1506, the procedure 1500 estimates the fuel consumption in cylinder modes that are permitted. The permitted cylinder modes are taken from 1406 in 14 . In one example, a brake-specific fuel table or function that is based on cylinder modes from the approved cylinder modes to 14 , engine speed, and desired engine torque. The values stored in the brake fuel table can be empirically determined and stored in the controller's memory. The brake fuel table can be adjusted using functions based on ignition timing from minimum spark for best torque (MBT); intake valve closure from a nominal intake valve closure; engine air-fuel ratio; and engine temperature. The functions output empirically determined multipliers that modify the brake fuel value output from the table. The brake fuel values for each allowable cylinder mode at the current engine speed are output from the brake fuel table. For example, based on the example described at 1406, the actual number of cylinders engaged is three and four, since three- and four-cylinder modes provide the desired engine torque. Procedure 1500 goes to 1508.

At 1508, method 1500 compares the fuel consumption for the permitted cylinder modes that can provide the requested torque. In one example, the current engine fuel consumption, which can be determined from the current engine fuel flow rate, is compared to values output from the brake-specific fuel table for permitted cylinder modes. The comparison may be performed by subtracting the values output from the brake-specific fuel table from the current engine fuel consumption rate. Alternatively, the comparison may be based on dividing the current engine fuel consumption value by the values output from the brake-specific fuel table. Cylinder modes that provide a percentage improvement in engine fuel economy greater than a threshold compared to the current cylinder mode are permitted.

Therefore, cylinder modes and fuel consumption in the cylinder modes can be used to determine which cylinder mode the engine operates in. Furthermore, cylinder modes with lower fuel consumption can be given selection priority, thus saving fuel.

At this point, 16 which shows a method for evaluating a cam phase control rate for cam torque actuated cam phasing. The method according to 16 can be integrated into the system that is 1A-6C The procedure according to 16 may be contained as executable instructions stored in non-volatile memory. The method according to 16 may be performed cooperatively with the system hardware and other methods described herein to transform an operating state of an engine or its components. Method 1600 may be performed for each camshaft of the engine.

At 1602, method 1600 determines engine conditions. The engine conditions may include, among other things, an actual total number of cylinder valves deactivated during an engine cycle, engine speed, driver demand torque, vehicle speed, engine temperature, and ambient temperature. Method 1600 proceeds to 1604 after the operating conditions are determined.

At 1604, method 1600 judges whether one or more cylinder valves are deactivated. Method 1600 may judge that one or more cylinders are deactivated based on a value of a bit stored in memory, an output from a sensor that measures valve actuator position, cylinder pressure sensors, or other sensors. If method 1600 judges that one or more cylinder valves are deactivated, the answer is yes and method 1600 proceeds to 1606. Otherwise, the answer is no and method 1600 proceeds to 1634.

At 1606, method 1600 assesses whether an adjustment of the camshaft position relative to the crankshaft position is desired. For example, method 1600 assesses whether it is desirable to advance the camshaft timing by 5 degrees relative to the crankshaft timing, such that the intake or exhaust valves open 5 degrees of crankshaft rotation earlier after the camshaft position is adjusted. The camshaft position may be adjusted in response to driver demand torque and engine speed. number can be adjusted. If the driver demand torque increases rapidly and the engine speed increases rapidly, it may be desirable to adjust the camshaft position relative to the crankshaft position at a faster rate so that the engine provides a desired level of torque and engine emissions. In one example, method 1600 determines whether adjustment of the camshaft position relative to the crankshaft position is desired based on a current camshaft position relative to the crankshaft position and a change in driver demand torque and engine speed. If method 1600 judges that adjustment of the camshaft position is desired, the answer is yes and method 1600 proceeds to 1608. Otherwise, the answer is no and method 1600 proceeds to 1634. In some examples, 1606 may be omitted and method 1600 may simply proceed to 1608.

At 1608, method 1600 determines a desired rate of change in camshaft position relative to crankshaft position. In one example, method 1600 determines a desired rate of change in camshaft position based on a rate of change in driver demand torque. If the rate of change in driver demand torque is low, then the rate of change in camshaft position relative to crankshaft position is low. If the rate of change in driver demand torque is high, then the rate of change in camshaft position relative to crankshaft position is high. For example, the camshaft may be advanced at 0.5 degrees of crankshaft rotation per second when a change in driver demand torque is low (e.g., 5 N-m/second). However, if the change in driver demand torque is high (e.g., 200 N-m/second), the camshaft may be advanced at 5 degrees of crankshaft rotation per second. In one example, the desired rate of change in camshaft position relative to crankshaft position is empirically determined and stored in a table or function in memory. The table or function is populated based on a rate of change in driver demand torque; the table or function outputs a desired rate of change in camshaft position relative to crankshaft position. Method 1600 proceeds to 1610 after the desired rate of change in camshaft position is determined.

At 1610, method 1600 judges whether an actual total number of energized cylinder valves (e.g., valves that open and close during an engine cycle) currently operating is sufficient to move the camshaft relative to the crankshaft at the desired rate. In one example, a table or function describes a camshaft rate of position change relative to the crankshaft position based on an actual total number of energized cylinder valves. The table is populated with the actual total number of energized valves, and it outputs a rate of camshaft position change relative to the crankshaft position. The values in the table or function are empirically determined and stored in memory. The output from the table or function is compared to the value determined at 1608. If the camshaft rate of position change from 1610 is greater than the camshaft rate of position change from 1608, the answer is yes, and method 1600 proceeds to 1634. Otherwise the answer is no and procedure 1600 goes to 1612.

At 1612, method 1600 judges whether the camshaft drives both the intake and exhaust valves. In one example, a bit in memory determines that the camshaft drives only the intake valves if a value of the bit is zero. If the value of the bit is one, then the camshaft drives both the intake and exhaust valves. If method 1600 judges that the camshaft drives both the intake and exhaust valves, the answer is yes and method 1600 proceeds to 1630. Otherwise, the answer is no and method 1600 proceeds to 1614.

At 1614, method 1600 judges whether the camshaft is an intake camshaft. Method 1600 may judge whether the camshaft is an intake camshaft based on a value of a bit stored in memory. The bit may be programmed at the time of manufacture. If method 1600 judges that the camshaft is an intake camshaft, the answer is yes and method 1600 proceeds to 1616. Otherwise, the answer is no and method 1600 proceeds to 1620.

At 1620, method 1600 allows for the activation of one or more deactivated exhaust valves. In one example, the desired rate of change in exhaust camshaft position relative to the crankshaft position determined at 1608 is used to maintain a table or function of empirically determined values describing an actual total number of valves that must operate to achieve the desired rate of adjustment of exhaust camshaft position relative to the crankshaft position. Method 1600 requests or allows driving the actual total number of exhaust valves output by the table or function. The exhaust valves may be turned on with or without energizing the cylinders comprising the exhaust valves being turned on. As driver demand torque increases, the cylinders with the exhaust valves being turned on may be turned on to increase engine torque while increasing the camshaft position change. As driver demand torque decreases, the cylinders with the exhaust valves being turned on may not be turned on so that fuel consumption may be reduced. Method 1600 proceeds to 1634.

At 1634, method 1600 moves the camshaft and drives valves for operating conditions that caused the camshaft to be moved. The camshaft may be moved while valves are energized to move the camshaft to a desired position as quickly as possible. Once the camshaft reaches its desired position relative to the crankshaft position, the cylinder valves may be deactivated based on vehicle conditions other than the desired rate of change in the camshaft position. Thus, valves may be reactivated to improve a rate at which a camshaft position moves relative to a crankshaft position. The engine cylinders may also be reactivated when the cylinder valves are reactivated. Method 1600 proceeds to end after the camshaft begins to move to its desired new position based on driver demand torque and engine speed.

At 1616, method 1600 allows for the activation of one or more deactivated intake valves. In one example, the desired rate of change in intake camshaft position relative to the crankshaft position determined at 1608 is used to populate a table or function of empirically determined values describing an actual total number of valves that must operate to provide the desired rate of adjustment of intake camshaft position relative to crankshaft position. Method 1600 requests or allows the actual total number of intake valves output from the table or function to be driven. The cylinders that include the intake valves that are activated may be activated or they may not combust air and fuel during engine cycles in which intake valves are operated. In one example, the cylinders with intake valves that are activated combust air and fuel over the course of engine cycles in response to an increase in driver demand torque. Cylinders with intake valves switched on cannot combust air and fuel during engine cycles in response to a reduction in driver demand torque. Deactivated intake valves can 22 described.

Additionally, method 1600 may increase an amount of boost provided to the engine so that the additional boost can blow exhaust gases out of the cylinder before the exhaust valve of the cylinder being reactivated is closed. By removing exhaust gases from the cylinder, combustion stability may improve, and the cylinder may provide additional power. Additionally, an amount of overlap (e.g., opening time) between the intake valves and exhaust valves of the cylinder may be increased to further allow pressurized air from the intake manifold to clear the cylinder being activated. Method 1600 proceeds to 1634 after the intake valves are activated.

At 1630, method 1600 assesses whether engine noise, vibration, and harshness (NVH) are below threshold levels when one or more cylinders are reactivated and combustion occurs in the reactivated cylinders. In one example, method 1600 assesses whether reactivating one or more cylinders, including combustion of air and fuel in the reactivated cylinder, results in higher than desired NVH based on an output from a table or function describing engine and/or powertrain NVH. The table is populated via engine speed, driver demand torque, and the cylinder mode being activated (e.g., four- or six-cylinder mode). The table outputs a numeric value that is empirically determined, for example, via a microphone or accelerometer. If the output value is below a threshold, the answer is yes, and method 1600 proceeds to 1632. Otherwise the answer is no and procedure 1600 goes to 1640.

At 1632, method 1600 allows one or more cylinders to be turned on by turning on the cylinder's valves and supplying fuel, air, and spark to the cylinder. The cylinder will begin combusting air and fuel when it is turned back on. Therefore, if the re-turning of one or more cylinders is used to increase the camshaft rate of the position If the change causes less disruptive NVH, the cylinder is reactivated by reactivating the cylinder's valves and commencing combustion in the reactivated cylinder. Method 1600 proceeds to 1634.

At 1640, method 1600 allows for the energization of one or more valves of a deactivated cylinder that is not combusting air and fuel. If the cylinder includes deactivated intake and exhaust valves, only the cylinder's exhaust valves may be energized to improve the rate of adjustment of the camshaft position relative to the crankshaft position. By reactivating the cylinder's exhaust valves alone, cam torque may be increased to improve the rate of adjustment of the camshaft position relative to the crankshaft position without allowing air to flow through the cylinder. Stopping airflow through the cylinder may help keep the catalyst temperature high and maintain a desired amount of oxygen in the catalyst. If both the cylinder's intake and exhaust valves are reactivated, air may flow through the cylinder after the intake and exhaust valves are activated. Spark and fuel are not supplied to cylinders with the valves reactivated, preventing NVH deterioration. Procedure 1600 proceeds to 1642.

At 1642, method 1600 increases an amount of fuel supplied to an activated cylinder combusting air and fuel to enrich the mixture combusted by the activated cylinder when air flows through the cylinder for which one or more valves are permitted to be activated at 1640. By enriching the mixture of an activated cylinder combusting air and fuel while air flows through a cylinder, it may be possible to maintain desired levels of hydrocarbons and oxygen in a catalyst so that the catalyst can efficiently convert exhaust gases. For example, if cylinder number eight of an eight-cylinder engine has its own intake and exhaust valves reactivated while cylinder number eight is not combusting air and fuel, then the air-fuel ratio of cylinder number one combusting air and fuel may be enriched to improve or maintain the efficiency of the catalyst. Method 1600 proceeds to 1634 after the air-fuel ratio of at least one cylinder has been enriched.

Now with reference to 17 a sequence for operating an engine according to the method of 16 The vertical lines at time points T1700-T1704 represent relevant time points in the sequence. 17 shows six representations, and the representations are time-aligned and occur simultaneously. In this example, the engine is a four-cylinder engine with a firing order of 1-3-4-2. Cylinders 2 and 3 have deactivation valve actuators to deactivate cylinders 3 and 4. The valves of cylinders 1 and 4 remain on at all times.

The first representation from above in 17 is a plot of a camshaft motion request versus time. A camshaft motion request is a request to change a camshaft position relative to a crankshaft position. For example, if a camshaft has a lobe that begins to open an intake valve of an engine's number one cylinder 370 degrees of crankshaft rotation before top dead center of the compression stroke (e.g., crankshaft position at zero degrees), then the camshaft position can be moved relative to the crankshaft so that the camshaft lobe begins to open the engine's number one cylinder's intake valve at 380 degrees of crankshaft rotation before top dead center of the compression stroke. Consequently, the camshaft's relative position is advanced by 10 degrees of crankshaft rotation relative to the crankshaft position in this example.

The vertical axis represents the camshaft motion request. The camshaft motion request trace is at a higher level and is asserted when it is desired to move the engine camshaft relative to the engine crankshaft. The camshaft motion request trace is at a lower level and is not asserted when it is not desired to move the engine camshaft relative to the engine crankshaft. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 17 is a plot of camshaft position versus time. The vertical axis represents the camshaft position, and the camshaft is advanced in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 17 is a representation of the state of the deactivation cylinder inlet valve. In this example, the deactivation cylinder can be cylinder number two or cylinder number three. The state of the deactivation cylinder inlet valve indicates whether the deactivation cylinder's inlet valve is on (e.g., opening and closing during an engine cycle) or off (e.g., held closed for an entire engine cycle). The vertical axis represents the state of the deactivation cylinder inlet valve. The deactivation cylinder inlet valve is on when the trace is at a higher level near the vertical axis arrow. The deactivation cylinder inlet valve is off when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 17 is a representation of the state of the deactivation cylinder exhaust valve. In this example, the deactivation cylinder can be cylinder number two or cylinder number three. The state of the deactivation cylinder exhaust valve indicates whether the deactivation cylinder's exhaust valve is on (e.g., opening and closing during an engine cycle) or off (e.g., held closed during an engine cycle). The vertical axis represents the state of the deactivation cylinder exhaust valve. The deactivation cylinder exhaust valve is on when the trace is at a higher level near the vertical axis arrow. The deactivation cylinder exhaust valve is off when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 17 is a representation of the deactivation cylinder fuel flow state. In this example, the deactivation cylinder can be cylinder number two or cylinder number three. The deactivation cylinder fuel flow state indicates whether fuel is flowing to the deactivation cylinder or not. The vertical axis represents the deactivation cylinder fuel flow state. Fuel flows to the deactivation cylinder when the deactivation cylinder fuel flow trace is at a higher level near the vertical axis arrow. Fuel does not flow to the deactivation cylinder when the deactivation cylinder fuel flow trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 17 is a representation of the air-fuel ratio of the activated cylinder. In this example, the activated cylinder can be cylinder number 1 or cylinder number 4. The vertical axis represents the air-fuel ratio of the activated cylinder, and the air-fuel ratio increases (e.g., becomes leaner) in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The horizontal line 1702 represents a stoichiometric air-fuel ratio.

At time T1700, there is no camshaft motion request and the camshaft is relatively retarded. The deactivation cylinder intake valve state indicates that the deactivation cylinder intake valve is deactivated (e.g., does not open during an engine cycle). The deactivation cylinder exhaust valve state indicates that the deactivation cylinder exhaust valve is deactivated (e.g., does not open during an engine cycle). The activated cylinder is operating at a stoichiometric air-fuel ratio, and no fuel is flowing to the deactivation cylinder, as indicated by the deactivation cylinder fuel flow state being at a low level.

At time T1701, the camshaft motion request is asserted, requesting a change in camshaft position relative to an engine crankshaft position. The request may be initiated via an increase in driver demand torque or a change in another operating condition. The rate of change of the engine camshaft position relative to the engine crankshaft position (not shown) is greater than that achievable with the deactivation cylinder intake and exhaust valves deactivated because driving fewer valves provides less torque to actuate camshaft motion. Therefore, the intake and exhaust valves of the deactivation cylinder are reactivated, indicated by the deactivation cylinder intake and exhaust valve states transitioning to higher levels to indicate that the deactivation cylinder intake and exhaust valves are reactivated. Additionally, fuel flows to the deactivation cylinder, and combustion begins in the deactivation cylinder (not shown). The camshaft position is advanced while the deactivation cylinder intake and exhaust valves are activated. The air-fuel ratio of the activated cylinders is stoichiometric.

At time T1702, the camshaft motion request transitions to an unasserted state. The camshaft motion request may transition to unasserted when the camshaft reaches its destination. Further, fuel flow to the deactivation cylinder stops, and combustion in the deactivation cylinder stops (not shown). The camshaft position reaches a moderately advanced position, and its position is maintained. The air-fuel ratios of the activated cylinders remain stoichiometric.

At time T1703, the camshaft motion request is reasserted, requesting a change in camshaft position relative to an engine crankshaft position. The request may be initiated via an increase in driver demand torque or a change in another operating condition. The rate of change of engine camshaft position relative to the engine crankshaft position (not shown) is greater than that achievable with the deactivation cylinder intake and exhaust valves deactivated because driving fewer valves provides less torque to actuate camshaft motion. Consequently, the deactivation cylinder intake and exhaust valves are reactivated, indicated by the deactivation cylinder intake and exhaust valve states transitioning to higher stages to indicate that the deactivation cylinder intake and exhaust valves are reactivated. Fuel flow to the deactivation cylinders remains paused. In this example, combustion is not reinitiated in the deactivation cylinders because reactivating the deactivation cylinders is expected to produce greater than desired NVH levels. The camshaft position is advanced while the deactivation cylinder intake and exhaust valves are on. The air-fuel ratio of the on-cylinder is enriched so that when the enriched exhaust gas from the on-cylinder combines with oxygen from the deactivation cylinders, stoichiometric exhaust gases are provided to the catalyst.

At time T1704, the camshaft motion request transitions to an unasserted state. The camshaft motion request may transition to unasserted when the camshaft reaches its destination. Further, the intake and exhaust valves of the deactivating cylinder are energized, as indicated by the deactivating cylinder intake and exhaust valve states. The camshaft position reaches a fully advanced position and is maintained. The air-fuel ratios of the energized cylinders return to a stoichiometric air-fuel ratio by leaning the air-fuel mixtures of the deactivating cylinders.

For example, cylinder intake and exhaust valves that have been deactivated can be reactivated to provide faster engine camshaft position adjustments. Furthermore, stoichiometric exhaust gases can be supplied to a catalyst to maintain catalyst efficiency, regardless of whether air or exhaust gases are flowing from the deactivated cylinders.

At this point, 18 which shows a method for judging whether or not to shift transmission gears when evaluating cylinder mode changes. The method according to 18 can be integrated into the system that is 1A-6C The procedure according to 18 may be contained as executable instructions stored in non-volatile memory. The method according to 18 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 1802, method 1800 determines a desired wheel torque. In one example, the desired wheel torque is based on the accelerator pedal position and the vehicle speed. For example, the accelerator pedal position and the vehicle speed are entered into a table that outputs a desired wheel torque. The values in the table may be empirically determined and stored in the memory of the controller. In other examples, the accelerator pedal position and the vehicle speed may be entered into a table that outputs a desired engine braking torque or torque at another powertrain location (e.g., transmission input shaft). The output from the table is compared with ratios between the torque location (e.g., engine), torque converter multiplication and driveline torque losses to estimate the desired wheel torque. Method 1800 proceeds to 1804.

At 1804, method 1800 determines the currently selected transmission gear. Method 1800 may determine the currently selected transmission gear via a value of a location in the controller's memory. For example, a variable in the memory may have a value range of 1-10, indicating the currently selected gear ratio. Method 1800 proceeds to 1806.

At 1806, method 1800 estimates the engine fuel consumption in cylinder modes that can provide the desired wheel torque in the current transmission gear. Method 1800 determines the engine brake-specific fuel consumption in the current transmission gear according to the method of 15 . The procedure 1800 goes to 1808.

At 1808, method 1800 estimates the engine fuel consumption in cylinder modes that can provide the desired wheel torque in the next higher transmission gear. For example, if the transmission is currently in 3rd gear, the engine fuel consumption to provide equivalent wheel torque with the transmission in 4th gear is determined. In one example, method 1800 determines the engine brake-specific fuel consumption in the next higher transmission gear as follows: The current vehicle speed is divided by the gear ratio between the engine and the wheels, including the next higher transmission gear, to estimate the engine speed in the next higher transmission gear. The current wheel torque is divided by the gear ratio between the engine and the wheels to estimate the engine torque to provide equivalent wheel torque in the next higher transmission gear. The gear ratio between the engine and the wheels may also compensate for the torque converter, if present. Method 1800 determines cylinder modes that provide the desired wheel torque in the next higher transmission gear according to the method of 14 using the estimate of the engine torque in the next higher transmission gear that provides a wheel torque equivalent to the current wheel torque. It should be noted that the present wheel torque may be the desired wheel torque. The estimated engine fuel consumption is then calculated as described in the method description of 15 determined. Procedure 1800 proceeds to 1810.

At 1810, method 1800 estimates the engine fuel consumption in cylinder modes that can provide the desired wheel torque in the next lower transmission gear. For example, if the transmission is currently in 3rd gear, the engine fuel consumption to provide equivalent wheel torque with the transmission in 2nd gear is determined. In one example, method 1800 determines the engine brake-specific fuel consumption in the next lower transmission gear as follows: The current vehicle speed is divided by the gear ratio between the engine and the wheels, including the next lower transmission gear, to estimate the engine speed in the next higher transmission gear. The current wheel torque is divided by the gear ratio between the engine and the wheels to estimate the engine torque to provide equivalent wheel torque in the next lower transmission gear. The gear ratio between the engine and the wheels may also compensate for the torque converter, if present. Method 1800 determines cylinder modes that provide the desired wheel torque in the next lower transmission gear according to the method of 14 using the estimate of the engine torque in the next lower transmission gear that provides a wheel torque equivalent to the current wheel torque. Note that the present wheel torque may be the desired wheel torque. The estimated engine fuel consumption is then calculated as described in the method description of 15 determined. The procedure 1800 proceeds to 1812.

In some examples, method 1800 estimates engine fuel consumption in cylinder modes that can provide the desired wheel torque for all transmission gears. For example, if the transmission is currently in 3rd gear and the transmission includes five forward gears, the engine fuel consumption for providing equivalent wheel torque with the transmission in gears 1, 2, 4, and 5 is determined. In this way, it may be possible to select which gear provides the greatest improvement in vehicle fuel economy.

At 1812, method 1800 allows engagement of transmission gears and cylinder modes that provide a percentage reduction in engine fuel consumption that is greater than a threshold compared to the current cylinder mode and transmission gear. In one example, the brake-specific engine fuel consumption is increased in engine cylinder modes that achieve the desired engine speed. torque or wheel torque in the next higher transmission gear is divided by the brake-specific fuel consumption of the engine in the current cylinder mode and current transmission gear. If the result is above a threshold, the engine cylinder modes that provide the desired engine torque or wheel torque in the next higher transmission gear are permitted. Similarly, the engine fuel consumption in engine cylinder modes that provide the desired engine torque or wheel torque in the next lower transmission gear is compared to the engine fuel consumption in the current cylinder mode and current transmission gear. If the result is above a threshold, the engine cylinder modes that provide the desired engine torque or wheel torque in the next lower transmission gear are permitted. Additionally, according to method 1800, an expected noise level and an expected vibration level in a new gear (e.g., a higher or lower gear than the current transmission gear) may be required to be below threshold noise and vibration values. The levels of noise and vibration can be adjusted as 22 described. Furthermore, the transmission may be shifted back to its previous gear state if an engine knock sensor or other sensor detects engine vibration that exceeds a threshold following a transmission gear change.

Now with reference to 19 a sequence for operating an engine according to the method of 18 The vertical lines at time points T1900-T1905 represent relevant time points in the sequence. 19 shows four plots, and the plots are time-aligned and occur simultaneously. In this example, the vehicle is maintained at a constant speed, and the requested wheel torque is varied to maintain the constant vehicle speed. The vehicle includes a four-cylinder engine.

The first representation from above in 19 is a plot of requested wheel torque versus time. In one example, the requested wheel torque is based on the accelerator pedal position and vehicle speed. The requested wheel torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 19 is a plot of the engaged transmission gear versus time. The vertical axis represents the currently engaged transmission gear, and the transmission gears are indicated on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 19 is a plot of the actual total number of engine cylinders engaged versus time. The actual total number of engine cylinders engaged is shown on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 19 is a plot of estimated engine fuel consumption versus time. The vertical axis represents estimated engine fuel consumption, and estimated engine fuel consumption increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. Trace 1902 represents engine fuel consumption when the engine is operating with the transmission in third gear. Trace 1904 represents engine fuel consumption when the engine is operating with the transmission in second gear.

At time T1900, the requested wheel torque is at a lower intermediate level and the transmission is in third gear. The actual total number of engine cylinders engaged is two, and the estimated engine fuel consumption is at an intermediate level.

Between time T1900 and time T1901, the requested wheel torque gradually increases. The engaged or current transmission gear is third gear, and the actual total number of engaged engine cylinders is two. The estimated engine fuel consumption for operating the engine in second gear is higher than the estimated engine fuel consumption for operating the engine in third gear.

At time T1901, the wheel torque has increased to a value at which the estimated fuel consumption of the engine to run the engine while the transmission is in second gear gear is less than the estimated fuel consumption to run the engine while the transmission is in third gear. Therefore, the transmission will downshift to increase the vehicle's fuel efficiency.

The number of cylinders activated remains at a value of two, and the estimated fuel consumption increases with increasing requested wheel torque.

At T1902, the number of activated cylinders increases from two to three in response to the increase in requested wheel torque. The requested wheel torque and engine fuel consumption continue to increase. The transmission remains in second gear.

At T1903, the number of activated cylinders increases from three to four in response to the increase in requested wheel torque. The requested wheel torque and engine fuel consumption continue to increase. The transmission remains in second gear as the requested wheel torque increases.

At time T1904, the requested wheel torque decreases and has dropped to a level where the estimated engine fuel consumption to operate the vehicle in third gear is less than the estimated engine fuel consumption to operate the vehicle in second gear. Therefore, the transmission gear is shifted to third gear. The actual total number of activated cylinders is also decreased in response to the decreasing requested wheel torque.

At 1904, the requested wheel torque has decreased to a level where the actual total number of engaged cylinders is reduced from three to two. The transmission remains in third gear, and the estimated engine fuel consumption decreases as the requested engine torque decreases.

At this point, 20 which shows a method for evaluating tow/pull modes to select cylinder mode or VDE mode. The method according to 20 can be integrated into the system that is 1A-6C The procedure according to 20 may be contained as executable instructions stored in non-volatile memory. The method according to 20 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

It may be more desirable to drive a cylinder with closed intake and exhaust valves and with air or exhaust trapped within the cylinder during an engine cycle because the vehicle can coast longer since the trapped air or exhaust provides a spring-like function that reduces cylinder braking torque. Furthermore, closing the intake and exhaust valves limits airflow to the catalyst in the exhaust system, so excess fuel may not need to be added to the engine exhaust to consume excess oxygen in the catalyst. However, during tow/haul and hill descent modes, it may be desirable to provide higher levels of cylinder braking torque, so it may be desirable to open and close intake and exhaust valves.

At 2002, method 2000 judges whether the engine is or should be in fuel cut-off deceleration mode. In fuel cut-off deceleration mode, one or more engine cylinders may be shut off by stopping fuel flow to the cylinders. Further, gas flow through one or more cylinders may be stopped via shutting off intake valves or intake and exhaust valves of a cylinder that is shut off in closed positions as the engine rotates through an engine cycle. Thus, shut off cylinders do not combust air and fuel. In one example, method 2000 judges that the engine should be in fuel cut-off deceleration mode when driver demand decreases from a higher value to a lower value and vehicle speed is above a threshold speed. If method 2000 judges that the engine should be in fuel cut-off deceleration mode, the answer is yes and method 2000 proceeds to 2004. Otherwise, the answer is no and the 2000 procedure moves to 2020.

At 2020, process 2000 drives all engine cylinders, and all cylinder valves are switched on. Furthermore, all engine cylinders combust air and fuel mixtures. Alternatively, fewer than all Engine cylinders are activated when driver demand torque is low. Procedure 2000 proceeds to completion after the cylinders are activated.

At 2004, method 2000 judges whether the vehicle is in a tow or pull mode. In one example, method 2000 judges that the vehicle is in a tow or pull mode based on an operating state of a push button, switch, or variable in memory. If method 2000 judges that the vehicle is in a tow or pull mode, the answer is yes and method 2000 proceeds to 2006. Otherwise, the answer is no and method 2000 proceeds to 2030.

A vehicle may have a transmission that shifts according to a first shift schedule (e.g., transmission shifts based on driver demand torque and vehicle speed) when the vehicle is not in a tow or haul mode. The vehicle's transmission shifts according to a second shift schedule when in a tow or haul mode. The second shift schedule may upshift at higher driver demand torques and higher vehicle speeds than the first shift schedule. The second shift schedule may downshift at higher vehicle speeds to increase driveline braking.

At 2006, method 2000 determines a desired amount of engine braking torque for cylinders that are not combusting air and fuel. In one example, the desired amount of engine braking torque may be an empirically determined input to a table or function. The table or function may be populated using driver demand torque, vehicle speed, and transmission gear. The table outputs the desired engine braking torque (e.g., a negative braking torque that the engine provides to the powertrain to decelerate the vehicle powertrain). Method 2000 proceeds to 2008 after the desired engine braking torque is determined.

At 2008, method 2000 shifts the transmission gears according to a second gear shift schedule. For example, the transmission may upshift from first to second gear when the driver demand torque is above 50 N-m and the vehicle speed is 16 KPH. The second transmission gear shift schedule upshifts transmission gears at higher engine speeds and higher vehicle speeds than the first transmission gear shift schedule. The second transmission gear shift schedule also downshifts transmission gears at higher engine speeds and higher vehicle speeds than the first transmission shift schedule to provide additional engine braking compared to the first transmission gear shift schedule. The second transmission gear shift schedule upshifts transmission gears at lower engine speeds and lower vehicle speeds than the third transmission gear shift schedule. The second transmission gear shift schedule downshifts transmission gears at lower engine speeds and lower vehicle speeds than the third transmission shift schedule to provide less engine braking compared to the third transmission gear shift schedule. The 2000 procedure proceeds to 2010 after the transmission gears have been shifted according to the second transmission shift schedule.

At 2010, method 2000 determines the cylinder deactivation mode of each deactivated cylinder to achieve the desired engine braking torque provided across deactivated cylinders. Note that cylinder deactivation mode is different from cylinder mode. Cylinder deactivation mode defines how the valves of a deactivated cylinder are driven, while cylinder mode defines the actual total number of activated cylinders and the cylinders that are activated. In one example, a cylinder with intake and exhaust valves that open and close during an engine cycle without fuel injection (e.g., a first cylinder deactivation mode) and combustion is assigned a first braking torque. A cylinder with intake valves held closed throughout an engine cycle and exhaust valves that open and close throughout the engine cycle without fuel injection (e.g., a second cylinder deactivation mode) is assigned a second braking torque. A cylinder with intake and exhaust valves held closed throughout an engine cycle without fuel injection (e.g., a third cylinder deactivation mode) is assigned a third braking torque. The first braking torque is greater than the second braking torque, and the second braking torque is greater than the third braking torque. Therefore, the engine cylinders can provide three levels of braking torque in three different cylinder deactivation modes, and the desired braking torque can be provided by driving different cylinders at different levels of braking torque generation.

Furthermore, the assigned braking torque values for each of the three cylinder deactivation modes can be adjusted by adjusting the timing of intake valve closure. For example, the assigned braking torque values may be increased by retarding the timing of intake valve closure. Similarly, the assigned braking torque values may be decreased by advancing the timing of intake valve closure. In one example, a valve timing compensation function, input via outputs related to intake valve closure, outputs a value that is multiplied by the assigned first braking torque, the assigned second braking torque, and the assigned third braking torque to provide valve timing compensated cylinder braking torque values that are used to determine valve timing compensated braking torque values provided by the cylinders in the various cylinder modes. Additionally, an atmospheric pressure compensation function, fed after the atmospheric pressure, outputs a value that is multiplied by the valve timing-compensated braking torque values to provide values for the atmospheric pressure and the valve timing-compensated braking torque provided by the cylinders in the various cylinder deactivation modes. The intake and exhaust valve timing for each cylinder deactivation mode can be adjusted to increase or decrease the braking torque provided by the three cylinder deactivation modes based on atmospheric pressure and the desired engine braking torque. For example, if the atmospheric pressure decreases and the desired braking torque increases, the intake valve timing can be retarded in each of the three cylinder deactivation modes to compensate for the lower atmospheric pressure and the higher desired braking torque.

In one example, method 2000 determines the valve actuation for the engine cylinders according to the desired engine braking torque and the amount of valve timing and atmospheric pressure compensated braking torque each cylinder provides in the various operating modes. For example, in the case of a four-cylinder engine whose desired engine braking torque is 2.5 N-m, the deactivation modes of each cylinder are based on the valve timing and atmospheric pressure compensated braking torques the cylinders provide in the three different cylinder deactivation modes described above. If a cylinder provides 0.25 N-m of braking torque in the first cylinder deactivation mode, 0.5 N-m in the second cylinder deactivation mode, and 1 N-m in the third cylinder deactivation mode, the four-cylinder engine is operated with two cylinders in the third cylinder deactivation mode and two cylinders in the first cylinder deactivation mode.

The cylinder deactivation mode for each cylinder may be determined using method 2000, which evaluates the engine braking torque for all engine cylinders operating in the first cylinder deactivation mode. If the engine braking torque to operate the engine with all cylinders in the first cylinder deactivation mode is greater than or equal to the desired engine braking torque, all engine cylinders are allowed to operate in the first cylinder deactivation mode, in which the intake valves and exhaust valves are held closed while the engine rotates over the course of one engine cycle. If the engine braking torque to operate the engine with all cylinders in the first cylinder deactivation mode is less than the desired engine braking torque, an engine braking torque is determined to operate the engine with one cylinder in the second cylinder deactivation mode and three cylinders in the first cylinder deactivation mode. If the engine braking torque for operating the engine with one cylinder in the second cylinder deactivation mode and three cylinders in the first cylinder deactivation mode is greater than or equal to the desired engine braking torque, one cylinder is allowed to operate in the second cylinder deactivation mode and three cylinders are allowed to operate in the first cylinder deactivation mode. Otherwise, an engine torque for operating the engine with two cylinders in the second cylinder deactivation mode and two cylinders in the first cylinder deactivation mode is determined. In this manner, the cylinder deactivation modes of each cylinder can be sequentially incremented from the first cylinder deactivation mode to the third cylinder deactivation mode until the engine cylinder deactivation modes that provide the desired engine braking torque are determined.

If the vehicle is not in tow/haul or hill descent mode, it may be determined to be in a fuel-conservation mode during deceleration conditions. As such, an actual number of engine cylinders with intake and exhaust valves held closed during an engine cycle and not combusting air and fuel may be increased to improve the vehicle's coast-down time and fuel economy. For example, the intake and exhaust valves of all engine cylinders may be commanded to be held closed during an engine cycle. Method 2000 proceeds to 2050.

At 2050, method 2000 allows deactivation of the engine cylinders and their deactivation modes that provide the desired engine braking torque. According to the cylinder deactivation modes, the valves are allowed to be on or off, and no fuel is injected into the cylinders, so that no combustion occurs in the cylinders during the deceleration fuel deactivation mode.

At 2030, method 2000 judges whether the vehicle is in a hill descent mode. In one example, method 2000 judges that the vehicle is in a hill descent mode based on an operating state of a push button, a switch, or a variable in memory. If method 2000 judges that the vehicle is in a hill descent mode, the answer is yes and method 2000 proceeds to 2032. Otherwise, the answer is no and method 2000 proceeds to 2040.

In one example, the vehicle is regulated to a requested or desired speed when the accelerator pedal is not applied via regulation of the negative torque generated in hill descent mode via the engine and vehicle brakes. The vehicle may activate hill descent mode via a release of the accelerator pedal. Further, engine braking in hill descent mode may be regulated via adjusting the engine valve timing. Further, transmission gears may be shifted to provide desired braking at the vehicle wheels via the engine.

At 2032, method 2000 determines a desired amount of engine braking torque for cylinders that are not combusting air and fuel. In one example, the desired amount of engine braking torque may be an empirically determined input to a table or function. The table or function may be specific to the hill descent mode and different from the table or function for the tow/haul mode. The table or function may be populated via the driver demand torque, vehicle speed, and transmission gear. The table outputs the desired engine braking torque (e.g., a negative braking torque that the engine provides to the powertrain to decelerate the vehicle powertrain). Method 2000 proceeds to 2034 after the desired engine braking torque is determined.

At 2034, method 2000 shifts the transmission gears according to a third gear shift schedule. The third transmission gear shift schedule upshifts transmission gears at higher engine speeds and higher vehicle speeds than the first and second transmission gear shift schedules. The third transmission gear shift schedule also downshifts transmission gears at higher engine speeds and higher vehicle speeds than the first and second transmission gear shift schedules to provide additional engine braking compared to the first and second transmission gear shift schedules. Method 2000 proceeds to 2010 after the transmission gears are shifted according to the third transmission shift schedule.

At 2040, method 2000 determines a desired amount of engine braking torque for cylinders that are not combusting air and fuel. In one example, the desired amount of engine braking torque may be an empirically determined input to a table or function. The table or function may be specific to the fuel cut-off mode, other than tow/haul mode or hill descent mode. The table or function may be populated via the driver demand torque, vehicle speed, and transmission gear. The table outputs the desired engine braking torque (e.g., a negative braking torque that the engine provides to the powertrain to decelerate the vehicle powertrain). Method 2000 proceeds to 2042 after the desired engine braking torque is determined.

At 2042, method 2000 shifts the transmission gears according to a first gear shift schedule. The first transmission gear shift schedule upshifts transmission gears at lower engine speeds and lower vehicle speeds than the second and third transmission gear shift schedules. The first transmission gear shift schedule also downshifts transmission gears at lower engine speeds and lower vehicle speeds than the second and third transmission gear shift schedules to provide less engine braking compared to the second and third transmission gear shift schedules. Method 2000 proceeds to 2010 after the transmission gears are shifted according to the first transmission shift schedule.

This allows cylinders to operate in different modes, where valves can be turned on or off to regulate engine braking while stopping fuel flow to the engine cylinders. Different cylinders can operate in different modes to provide the desired engine braking torque.

Now with reference to 21 a sequence for operating an engine according to the method of 20 The vertical lines at time points T2100-T2108 represent relevant time points in the sequence. 21 shows six representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 21 is a plot of a deceleration fuel cut-off state versus time. The vertical axis represents the deceleration fuel cut-off state. The engine is in deceleration fuel cut-off mode when the trace is at a higher level near the vertical axis arrow. The engine is not in deceleration fuel cut-off mode when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 21 is a plot of downhill mode versus time. The vertical axis represents downhill mode, and the vehicle is in downhill mode when the trace is at a higher level near the vertical axis arrow. The vehicle is not in downhill mode when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 21 is a plot of the tow/haul state versus time. The vertical axis represents the tow/haul mode, and the vehicle is in tow/haul mode when the trace is at a higher level near the vertical axis arrow. The vehicle is not in tow/haul mode when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 21 is a plot of gear ratio versus time. The vertical axis represents gear ratio, and gear ratios are indicated on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 21 is a plot of the cylinder poppet valve state versus time. The vertical axis represents the state of the cylinder poppet valve. The poppet valve state can be on (e.g., poppet valves open and close during an engine cycle), off (e.g., poppet valves do not open and close during an engine cycle), partially on (PA) (e.g., intake valves are held closed during an engine cycle and exhaust valves open and close over the engine cycle). The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 21 is a plot of the fuel injection state versus time. The vertical axis represents the fuel injection state, and the fuel injection state is on when the trace is near the vertical axis arrow. Fuel injection is off when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time 2100, the engine cylinders are energized, and the cylinder valves are opening and closing throughout the engine cycle as the engine rotates and combusts air and fuel, as the poppet valves are energized and no fuel cutoff for deceleration is indicated. The vehicle is neither in hill descent nor tow/haul mode. The vehicle's transmission is in third gear, and all cylinder poppet valves are energized (e.g., opening and closing throughout the engine cycle). Fuel injection is energized, and fuel is being delivered to the engine cylinders.

At 2101, the engine enters fuel cut-off deceleration mode. The engine may enter fuel cut-off deceleration mode in response to low driver demand torque and the vehicle speed being above a threshold. The vehicle is neither in hill descent mode nor in tow/haul mode. The vehicle's transmission is in third gear, and all cylinder poppet valves are deactivated (e.g., not opening and closing). over the engine cycle). The cylinder poppet valves are deactivated, causing the engine cylinders to deactivate in a third cylinder deactivation mode in response to a small amount of engine braking torque (not shown). Furthermore, exhaust gas or fresh air is trapped within the cylinder, creating a spring-like effect on the piston. The closed intake and exhaust valves reduce engine pumping losses and can increase the distance the vehicle coasts. Closing the engine's intake and exhaust valves also stops the engine from pumping fresh air to the catalyst in the exhaust system, so the catalyst is not cooled as much as if fresh air were flowing to the catalyst. Furthermore, the amount of oxygen stored in the catalyst is not increased, allowing the catalyst's efficiency to be high when the engine cylinders resume combustion. Fuel injection to the engine's cylinders is also stopped, so no combustion occurs in the engine cylinders.

At time 2102, the engine exits the deceleration fuel cut-off mode, and the cylinder poppet valves are re-enabled, as indicated by the poppet valve state history. Fuel injection is also re-enabled, and combustion begins in the engine cylinder. The engine may exit the deceleration fuel cut-off mode in response to an increase in driver demand torque or vehicle speed below a threshold. The vehicle is neither in hill descent mode nor in tow/haul mode. The vehicle's transmission is in third gear.

At time 2103, the vehicle enters hill descent mode. The vehicle may enter hill descent mode by a driver pressing a push button or other input device. The vehicle is not in fuel cut-off deceleration mode, and it is not in tow/haul mode. The vehicle's transmission is in third gear, and the cylinder poppet valves are on. Additionally, fuel is being injected into engine cylinders, and the engine is combusting air and fuel.

At time 2104, the engine enters the deceleration fuel cut-off mode while in hill descent mode. The vehicle is not in tow/haul mode, and the transmission is in third gear. The cylinder poppet valves are partially deactivated in response to a mid-level engine braking torque request while the engine is rotating (e.g., intake valves are held closed during an engine cycle, and exhaust valves open and close during the engine cycle). The engine cylinders are in a second cylinder deactivation mode when the engine braking torque is at the mid-level. However, engine cylinders may enter the first mode if the vehicle is accelerating at a higher rate than desired. Similarly, the engine cylinders may enter the third cylinder deactivation mode if the vehicle is decelerating faster than desired. Fuel injection is deactivated, so there is no combustion in engine cylinders.

At time 2105, the vehicle exits the deceleration fuel cutoff mode in response to increasing driver demand torque or increasing vehicle speed below a threshold speed (not shown). The vehicle remains in hill descent mode, and the transmission is in third gear. The vehicle is not in tow/haul mode, and the cylinder poppet valves are re-enabled. Fuel injection to the engine cylinders is also re-enabled, allowing the engine cylinders to resume combustion of air and fuel.

Between time 2105 and time 2106, the vehicle exits hill descent mode. The driver can request exit from hill descent mode by providing an input to the vehicle or engine controller. The other engine/vehicle states remain at their previous levels.

At time 2106, the vehicle enters tow/haul mode. The vehicle may enter tow/haul mode by a driver pressing a pushbutton or switch that provides an input to the vehicle or engine controller. The other engine/vehicle states remain at their previous levels.

At time 2107, the engine enters fuel cut-off mode for deceleration in response to low driver demand torque and a vehicle speed exceeding a threshold speed. The vehicle is also in tow/haul mode. The transmission of the The vehicle is briefly downshifted to second gear after entering fuel cut-off deceleration mode to increase engine braking via an increase in engine speed (not shown). In response to a higher level engine braking torque request (not shown), all engine cylinder poppet valves remain energized. Fuel injection to the engine cylinders is terminated, and the engine does not combust air and fuel when the engine is rotating. Driving all cylinder valves while the engine throttle is closed (not shown) increases engine pumping losses and engine braking torque.

At 2108, the vehicle exits the deceleration fuel cutoff mode in response to reducing an increase in driver demand torque or engine speed to a level below a threshold. The vehicle remains in tow/haul mode, and the cylinder poppet valves remain enabled.

In this way, cylinder modes can be used in which cylinder poppet valves are driven differently to vary the engine braking torque, allowing a desired engine braking torque to be provided by the vehicle's engine. Furthermore, some engine cylinders can be in a first operating mode, while other engine cylinders are in a second or third operating mode, allowing the desired engine braking torque to be provided.

At this point, 22 which shows a method for selecting a cylinder mode from available cylinder modes. The method according to 22 can be integrated into the system that is 1A-6C The procedure according to 22 may be contained as executable instructions stored in non-volatile memory. The method according to 22 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 2202, method 2200 assesses whether baseline conditions exist to enable cylinder modes in which cylinders may be deactivated. The baseline conditions may include, but are not limited to: engine temperature is above a threshold, exhaust aftertreatment temperature is above a threshold, battery state of charge is above a threshold, and engine speed is above a threshold. Method 2200 checks whether the conditions exist or not by monitoring various system sensors. If method 2200 assesses that baseline conditions for cylinder deactivation and variable displacement engine operation exist, the answer is yes and method 2200 proceeds to 2204. Otherwise, the answer is no and method 2200 proceeds to 2220.

At 2220, method 2200 requests that all engine cylinders be turned on and combusting air and fuel. The intake and exhaust valves of turned-on cylinders open and close during an engine cycle, allowing air and combustion products to flow through turned-on cylinders. Spark and fuel delivery are also turned on, allowing fuel-air mixtures to be combusted in turned-on cylinders. Method 2200 proceeds to end.

At 2204, method 2200 estimates noise, vibration, and harshness (NVH) in the available cylinder modes. In one example, a noise table outputs empirically determined expected levels of audible noise for the engine/vehicle. The noise table is populated via the actual total number of engine cylinders engaged, engine speed, and engine torque. A vibration table outputs empirically determined expected levels of audible noise for the engine/vehicle. The vibration table is populated via cylinder mode, engine speed, and engine torque. The noise and vibration values are output for the current engine speed, the engine speed after a transmission gear shift, the current driver demand torque, and the driver demand torque after a transmission shift. Additionally, method 2200 may compare the outputs of vibration sensors (e.g., an engine knock sensor) and acoustic sensors to threshold levels for the purpose of eliminating currently enabled cylinder deactivation modes that may not provide a desired level of noise and vibration. Method 2200 proceeds to 2206.

At 2206, the method 2200 evaluates noise and vibration outputs from the noise and vibration tables. If the expected noise level from a table output exceeds a threshold or if the expected vibration level from a table output exceeds a threshold, the cylinder mode that provided the expected noise and vibration is excluded from the currently available cylinder modes. For example, if the expected engine noise for operating a four-cylinder engine in a second cylinder mode with two cylinders on at 2000 RPM exceeds a threshold at the current driver demand torque or the driver demand torque after a transmission shift, then the second cylinder mode at 2000 RPM is excluded from a list of available cylinder modes.

Alternatively, or additionally, method 2200 may compare noise and vibration sensor outputs to thresholds. If engine noise exceeds a threshold in a currently enabled cylinder mode, the currently enabled cylinder mode is excluded from the available cylinder modes so that a cylinder mode providing less engine noise may be selected. Similarly, if engine noise exceeds a threshold in a currently enabled cylinder mode, the currently enabled cylinder mode is excluded from the available cylinder modes so that a cylinder mode providing less engine noise may be selected.

Additionally, method 2200 may allow cylinder modes where the expected cylinder blowby air (e.g., the airflow from the engine intake manifold to the engine exhaust manifold not involved in combustion) is expected to be below a threshold immediately after a cylinder mode change. It may be desirable to avoid cylinder mode changes when the cylinder blowby air is above the threshold to avoid interfering oxygen in a downstream catalyst. The engine cylinder blowby amount may be determined according to the US patent application US 2013 / 0 111 900 A1 , submitted on 09 November 2011 , which is hereby incorporated by reference for all purposes. In one example, a table or function outputs an engine or cylinder blowby amount based on cylinder mode, engine speed, and cylinder valve timing. If the output from the table is less than the limit amount, the cylinder mode may be allowed. Method 2200 proceeds to 2208.

At 2208, the method 2200 allows cylinder modes that are available and that have not been excluded from the available cylinder modes. Furthermore, transmission gears that are available and have not been excluded are allowed. Cylinder modes may be allowed such that they ultimately operate the engine at 716 in 7 can be selected. A cylinder mode in which all engine cylinders are energized is always an authorized cylinder mode unless engine or valve wear is present. In one example, a matrix containing cells representing cylinder modes is used to track authorized and excluded cylinder modes. Cylinder modes can be authorized by inserting a value of one into cells corresponding to available cylinder modes. Cylinder modes can be excluded by inserting a value of zero into cells corresponding to cylinder modes that are unavailable or have been excluded from engine operation. As previously noted, different cylinder modes can have an equal number of total cylinders actually energized while having different cylinders energized. For example, if it is determined desirable to operate three cylinders of a four-cylinder engine to meet driver demand torque, cylinder mode numbers three and four can be authorized, with cylinder mode three having a firing order of 1-3-2 and cylinder mode four having a firing order of 3-4-2. During one engine cycle, cylinder mode three may be engaged. During a subsequent engine cycle, cylinder mode four may be engaged. In this way, the engine firing order may be varied while maintaining an actual total number of engaged cylinders. Method 2200 proceeds to exit.

In this way, it can be identified which cylinder deactivation modes should be made available or excluded. Furthermore, any baseline conditions must be met before available cylinder modes can be made permissible for engine operation.

At this point, 23 which shows a method for regulating engine intake manifold absolute pressure (MAP) during a deceleration fuel cut-off mode. The method according to 23 can be integrated into the system that is 1A-6C The procedure according to 23 may be contained as executable instructions stored in non-volatile memory. The method according to 23 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 2302, method 2300 judges whether the engine is or should be in deceleration fuel cut-off mode. In deceleration fuel cut-off mode, one or more engine cylinders, which may include all engine cylinders, may be shut down by stopping fuel flow to the cylinders. Further, gas flow through one or more cylinders may be stopped via shutting off intake valves or intake and exhaust valves of a cylinder that is shut down in closed positions as the engine rotates through an engine cycle. In one example, method 2300 judges that the engine should be in deceleration fuel cut-off mode when driver demand decreases from a higher value to a lower value and the vehicle speed is above a threshold speed. If method 2300 judges that the engine should be in deceleration fuel cut-off mode, the answer is yes and method 2300 proceeds to 2304. Otherwise the answer is no and procedure 2000 goes to 2320.

At 2320, method 2300 operates the engine to provide a desired amount of torque. The desired amount of torque may be a driver demand torque or may be based on the driver demand torque. The engine valves are turned on as requested to provide the desired torque, and the engine combusts air and fuel to provide the desired torque. Method 2300 proceeds to exit after the desired amount of torque is provided.

At 2304, method 2300 determines a desired intake manifold pressure and an actual total number of cylinder intake valve opening events (e.g., the intake valves of each cylinder open once during an intake stroke of the cylinder with opening intake valves) or intake strokes of cylinders introducing air to reduce the intake manifold pressure to a desired intake manifold pressure. The actual total number of cylinder intake valve opening events may be a better indicator of intake manifold pressure than the time required to pump down the intake manifold pressure. In one example, the methods described in U.S. Patent US 6 708 102 B2 or US patent US 6 170 475 B1 described, which are hereby incorporated by reference for all purposes, to estimate the intake manifold pressure for a desired number of intake valve opening events or intake strokes in the future. For example, in response to the activation of the fuel cut-off mode for deceleration, the throttle may follow a predetermined trajectory from its current position to a fully closed position. The predicted throttle position may be estimated from the predetermined trajectory using the following equation: $$\theta \left(k+1\right)=\theta \left(k\right)+\left[\theta \left(k\right)-\theta \left(k-1\right)\right]$$

Where θ(k + 1) is the estimate of the throttle position at the next engine intake event; θ(k) is the measured throttle position at the current engine intake event; and θ(k - 1) is the measured throttle position at the previous engine intake event.

wobei für die T die Temperatur im Ansaugkrümmer gemäß der Messung des Ansaugkrümmer-Temperatursensors steht, V für das Volumen des Ansaugkrümmers steht, R für die spezifische Gaskonstante steht, MAF der Massendurchsatz in den Ansaugkrümmer ist und M_cyl der Durchsatz in den Zylinder ist. Der Massendurchsatz in die Zylinder (M_cyl) ist als eine lineare Funktion des Drucks im Ansaugkrümmer repräsentiert, wobei die Steigung und der y-Achsenabschnitt wie folgt von der Motordrehzahl und den Umgebungszuständen abhängig sind: $$M_{cyl}={\alpha }_1\left(N\right)P_m-{\alpha }_2\left(N\right)\frac{P_{amb}}{P_{amb\_nom}}$$

wobei P_amb und P_{amb_nom} den aktuellen Umgebungsdruck und den nominalen Wert für den Umgebungsdruck (z. B. 101 kPa) darstellen. Die Motorpumpparameter α₁(N) und α₂(N) werden von den statischen Motorzuordnungsdaten regrediert, welche bei nominalen Umgebungszuständen erhalten wurden. Nachdem dieser Ausdruck in die dynamische Gleichung für den Druck im Ansaugkrümmer substituiert und beide Seiten differenziert wurden, um die Änderungsrate für den Druck im Ansaugkrümmer zu erhalten, erhält man: $${\ddot{P}}_m=\frac{RT}{V}\left[\frac{d}{dt}MAF-{\alpha }_1{\dot{P}}_m-{\dot{\alpha }}_1{P}_m-{\dot{\alpha }}_2\frac{P_{amb}}{P_{amb\_nom}}\right]$$

The gas in the engine's intake manifold is fresh air, and the pressure in the engine intake manifold is directly related to the cylinder air charge. The throttle position, the pressure in the intake manifold, the temperature in the intake manifold, and the engine speed are determined by various engine sensors. The starting point for determining the development of the pressure in the intake manifold is a standard dynamic model, which regulates the change in the pressure in the intake manifold as follows: $$P_m=\frac{RT}{V}\left(MAF-M_{cyl}\right)$$

where T is the temperature in the intake manifold as measured by the intake manifold temperature sensor, V is the volume of the intake manifold, R is the specific gas constant, MAF is the mass flow rate into the intake manifold, and M _cyl is the flow rate into the cylinders. The mass flow rate into the cylinders (M _cyl ) is represented as a linear function of the pressure in the intake manifold, with the slope and y-intercept depending on the engine speed and ambient conditions as follows: $$M_{cyl}={\alpha }_1\left(N\right)P_m-{\alpha }_2\left(N\right)\frac{P_{amb}}{P_{amb\_nom}}$$

where P _amb and P _{amb_nom} represent the current ambient pressure and the nominal value for the ambient pressure (e.g., 101 kPa). The engine pumping parameters α ₁ (N) and α ₂ (N) are regressed from the static engine mapping data obtained at nominal ambient conditions. After substituting this expression into the dynamic equation for the intake manifold pressure and differentiating both sides to obtain the rate of change for the intake manifold pressure, one obtains: $${\ddot{P}}_m=\frac{RT}{V}\left[\frac{d}{dt}MAF-{\alpha }_1{\dot{P}}_m-{\dot{\alpha }}_1{P}_m-{\dot{\alpha }}_2\frac{P_{amb}}{P_{amb\_nom}}\right]$$

The dynamics governing the change in engine speed are slower than the intake manifold dynamics. A good compromise between performance and simplicity is to retain α ₁ (slope) and omit α ₂ (y-intercept). With this simplification, the second derivative of P _m is given by: $${\ddot{P}}_M=\frac{RT}{V}\left[\frac{d}{dt}MAF-{\alpha }_1{\dot{P}}_m-{\dot{\alpha }}_1{P}_m\right]$$

To discretize the above equation, dP _m (k) is defined as a discrete version of the time derivative of P _m , i.e. dP _m (k)=(P _m (k+1)-P _m (k))/Δt, which gives us: $$\begin{array}{c}d{P}_m\left(k+1\right)=(1-\mathrm{\Delta }T{\alpha }_1\left(N\left(k\right)\frac{RT}{V}\right)d{P}_m+\frac{RT}{V}\left[MAF\left(k+1\right)-MAF\left(K-1\right)\right]\\ -\frac{RT}{V}\left[{\alpha }_1\left(N\left(k+1\right)\right)-{\alpha }_1\left(N\left(k\right)\right)\right]P_m\left(k\right)\end{array}$$

wobei P_amb und P_{amb_nom} für den aktuellen und nominalen (d. h. 101 kPa) absoluten Umgebungsdruck stehen, T_amb und T_{amb_nom} für die aktuelle und nominale (d. h. 300 K) absolute Umgebungstemperatur stehen und C(e) die Schallflusseigenschaft der Drossel ist, welche von den statischen Motordaten ausgehend erhalten wurde. Fn_Unterschall ist die Standardkorrektur für die Unterschallströmung: $$F{n}_{Unterschall}=\left\{\begin{array}{c}\sqrt{14.96501\left[{\left(\frac{P_m}{P_{amb}}\right)}^{1.42959}-{\left(\frac{P_m}{P_{amb}}\right)}^{1.7148}\right]}if\frac{P_m}{P_{amb}}\ge 0.52845\\ 1.0if\frac{P_m}{P_{amb}}<0.52845\end{array}\right\}$$

wobei P_m (k) die aktuelle Messung des Drucks im Ansaugkrümmer ist. Für die Umsetzung im Inneren des Fahrzeugs kann die Funktion Fn_Unterschall als eine tabellarisierte Nachschlagefunktion für das Druckverhältnis implementiert werden. In diesem Falle sollte der Umfang der Steigung begrenzt werden, um ein Oszillationsverhalten unter Zuständen einer weit geöffneten Drossel zu verhindern, und zwar möglicherweise durch ein Erweitern des Nulldurchgangs der Funktion auf einen Wert des Druckverhältnisses, der knapp über 1 liegt.Thus, the equation defines the predicted rate of change of intake manifold pressure around one engine event in the future, which is used to determine future intake manifold pressure values. However, the signals from the next (k+1) time point are not available at time k. To implement the right-hand side, instead of its value at time k+1, we use the one-event-before predicted value for the MAF signal at time k, obtained by using the one-event-before-the-throttle-position prediction, as follows: $$MA{F}^{+1}\left(k\right)=\frac{P_{amb}}{P_{amb\_nom}}\sqrt{\frac{T_{amb\_nom}}{T_{amb}}}C\left({\theta }^{+1}\left(k\right)\right)Fn\_Unterschall\left(\frac{P_m\left(k\right)+\mathrm{\Delta }td{P}^{+1}{}_m\left(k-1\right)}{P_{amb}}\right)$$

where P _amb and P _{amb_nom} are the current and nominal (i.e., 101 kPa) absolute ambient pressure, T _amb and T _{amb_nom} are the current and nominal (i.e., 300 K) absolute ambient temperature, and C(e) is the throttle sound flow characteristic obtained from the static engine data. Fn_subsonic is the standard correction for subsonic flow: $$F{n}_{Unterschall}=\left\{\begin{array}{c}\sqrt{14.96501\left[{\left(\frac{P_m}{P_{amb}}\right)}^{1.42959}-{\left(\frac{P_m}{P_{amb}}\right)}^{1.7148}\right]}if\frac{P_m}{P_{amb}}\ge 0.52845\\ 1.0if\frac{P_m}{P_{amb}}<0.52845\end{array}\right\}$$

where P _m (k) is the current intake manifold pressure measurement. For in-vehicle implementation, the Fn_Subsonic function can be implemented as a tabulated pressure ratio lookup function. In this case, the slope range should be limited to prevent oscillation under wide-open throttle conditions, possibly by extending the zero crossing of the function to a pressure ratio value just above 1.

There are several different choices available to obtain the quantity MAF(k) to be used to determine the future rate of change of the pressure in the intake manifold. The following formula, which uses the previous value for the predicted throttle position and the current value for the pressure in the intake manifold, provides the best performance in terms of overshoot and stability at wide open throttle: $$MAF\left(k\right)=\frac{P_{amb}}{P_{amb\_nom}}\sqrt{\frac{T_{amb\_nom}}{T_{amb}}}C\left({\theta }^{+1}\left(k-1\right)\right)Fn\_Unterschall\left(\frac{P_m\left(k\right)}{P_{amb}}\right)$$

To avoid predicting engine speed, instead of taking the present value of α ₁ from the prediction one step earlier, we approximate α ₁ by subtracting the old value from one event from the present one. The above changes result in the dP _m signal corresponding to the time derivative of P _m predicted one event earlier, i.e., the rate of change of the future pressure in the intake manifold: $$\begin{array}{c}d{P}_n^{+1}\left(k\right)=\left(1-\mathrm{\Delta }t{\alpha }_1\left(N\left(k\right)\right)\frac{RT}{V}\right)d{P}_m^{+1}\left(k-1\right)+\frac{RT}{V}\left[MA{F}^{+1}\left(k\right)-MAF\left(k\right)\right]\\ -\frac{RT}{V}\left[{\alpha }_1\left(N\left(k\right)\right)-{\alpha }_1\left(N\left(k-1\right)\right)\right]P_m\left(k\right)\end{array}$$

$$P_m^{+2}\left(k\right)=P_m\left(k\right)+\mathrm{\Delta }td{P}_m^{+1}\left(k-1\right)+\mathrm{\Delta }td{P}_m^{+1}\left(k\right)$$

wobei P_m ⁺¹ (k) und P_m ⁺² (k) Prognosen einen und zwei Schritte vor dem Druck im Ansaugkrümmer sind. Die Gleichungen für die Entwicklung des Drucks im Ansaugkrümmer über zwei Ansaugereignisse in der Zukunft hinaus ausgeweitet werden, auf eine Anzahl an Ansaugereignissen, welche den gewünschten Druck im Ansaugkrümmer bereitstellt. In einem Beispiel kann der gewünschte Druck im Ansaugkrümmer während des Abbremsungsmodus empirisch bestimmt und im Speicher gespeichert werden. Zum Beispiel kann der gewünschte Druck im Ansaugkrümmer auf Grundlage des Atmosphärendrucks und der Fahrzeuggeschwindigkeit empirisch bestimmt und in den Speicher eingepflegt werden. In einem Beispiel ist der gewünschte Druck im Motoransaugkrümmer ein Druck in dem Ansaugkrümmer, wenn der Motor bei Leerlaufdrehzahl arbeitet, wenn das Fahrer-Bedarfsdrehmoment null oder im Wesentlichen null ist (z. B. weniger als 10 N-m). Ferner kann der gewünschte Druck im Motoransaugkrümmer je nach Umgebungsdruck eingestellt werden. Steigt der Umgebungsdruck zum Beispiel, so kann der gewünschte Druck im Ansaugkrümmer des Motors gesenkt werden. Das Verfahren 2300 geht zu 2306 über, nachdem der gewünschte Druck im Ansaugkrümmer des Motors und die Anzahl der Zylinderansaugereignisse zum Erreichen des gewünschten Drucks im Ansaugkrümmer des Motors bestimmt wurden.Note that the value of dP _m ⁺¹ (k) depends only on the signals available at intake event k. Therefore, it can be used to predict intake manifold pressure as follows: $$P_m^{+1}\left(k\right)=P_m\left(k\right)+\mathrm{\Delta }td{P}_m^{+1}\left(k-1\right)$$

$$P_m^{+2}\left(k\right)=P_m\left(k\right)+\mathrm{\Delta }td{P}_m^{+1}\left(k-1\right)+\mathrm{\Delta }td{P}_m^{+1}\left(k\right)$$

where P _m ⁺¹ (k) and P _m ⁺² (k) are predictions one and two steps ahead of the intake manifold pressure. The equations for the evolution of intake manifold pressure are extended beyond two intake events in the future to a number of intake events that provide the desired intake manifold pressure. In one example, the desired intake manifold pressure during deceleration mode may be empirically determined and stored in memory. For example, the desired intake manifold pressure may be empirically determined and stored in memory based on atmospheric pressure and vehicle speed. In one example, the desired engine intake manifold pressure is a pressure in the intake manifold when the engine is operating at idle speed when the driver demand torque is zero or substantially zero (e.g., less than 10 Nm). Further, the desired engine intake manifold pressure may be adjusted depending on the ambient pressure. For example, if ambient pressure increases, the desired engine intake manifold pressure may be decreased. Method 2300 proceeds to 2306 after determining the desired engine intake manifold pressure and the number of cylinder intake events required to achieve the desired engine intake manifold pressure.

At 2306, method 2300 fully closes the engine throttle and completes all engine intake events after the number of intake events determined at 2304 to provide the desired engine intake manifold pressure has been performed. For example, if it is determined at 2304 that the desired intake manifold pressure is 75 kPa and that the desired intake manifold pressure can be achieved if the throttle closes in four cylinder intake valve opening events, cylinder intake valves, and in some cases exhaust valves, are closed such that a total actual number of cylinder intake events after fuel cut-off for deceleration is activated is four. In this way, cylinder valves are closed to provide a desired intake manifold pressure based on an actual total number of intake valve opening events since a fuel cut-off for deceleration mode request. Once the cylinder valves are closed, the engine can be started without evacuating air from the intake manifold. Consequently, less fuel can be used to enrich the engine exhaust to improve catalyst efficiency. Furthermore, the engine can operate with less spark retard when cylinders are reactivated because the cylinder charge is below full charge. Method 2300 proceeds to 2308.

At 2308, method 2300 closes the engine intake manifold to all vacuum consumers. Vacuum consumers may include, but are not limited to, vacuum reservoirs; vehicle brakes; heating, ventilation, and cooling systems; and vacuum actuators such as turbocharger wastegates. If the vacuum in man systems (e.g. brakes) is reduced to below a threshold value, the systems can be controlled by opening a valve 176, as shown in 1B shown, for vacuum to again access the engine intake manifold. Further, during such conditions, the valves may be re-enabled so that the engine may provide additional vacuum to vacuum consumers. In one example, selective access to the pressure in the engine intake manifold is provided to vacuum consumers via one or more solenoid valves. Method 2300 proceeds to 2310.

At 2310, method 2300 operates a vacuum source to maintain the intake manifold pressure of the engine at the desired level. If air escapes from the throttle, the intake manifold pressure may increase, so if the engine is restarted with the intake manifold pressure at atmospheric pressure, more fuel may be used to start the engine than desired. Consequently, if the engine is restarted with a higher intake manifold pressure than desired, the engine's fuel consumption may increase more than desired. Therefore, the vacuum source may be turned on in response to the intake manifold pressure being higher than the desired intake manifold pressure, so that the intake manifold pressure is lower than atmospheric pressure (e.g., there is a vacuum in the intake manifold). The vacuum source may be supplied with electrical energy generated via the vehicle's kinetic energy or a battery. Additionally, the vacuum source may be turned on to evacuate air from a vacuum vessel in response to a slight negative pressure in the vacuum vessel. Method 2300 proceeds to 2312.

At 2312, method 2300 ceases fuel flow and spark delivery to engine cylinders. Air introduced during intake events after the throttle begins to close, where the intake events correspond to the actual number of intake valve opening events determined at 2304, is combined with fuel and combusted before terminating fuel and spark delivery to engine cylinders. Method 2300 proceeds to 2314.

At 2314, method 2300 judges whether conditions exist to exit fuel cut-off for deceleration. In one example, fuel cut-off for deceleration may be exited in response to a driver demand torque being above a threshold or vehicle speed being below a threshold. If method 2300 judges that conditions exist to exit fuel cut-off for deceleration mode, the answer is yes and method 2300 proceeds to 2316. The engine continues to rotate during fuel cut-off for deceleration because some of the engine's kinetic energy may be transferred to the engine. Otherwise, method 2300 returns to 2310.

At 2316, method 2300 re-enables the cylinder valves so that the valves open and close during an engine cycle. Fuel flow and spark discharge are also provided to the cylinders. Combustion resumes in the cylinders, and the engine throttle position is adjusted to provide the desired engine airflow and engine torque. The cylinder valve timing and throttle positions may be empirically determined values stored in memory, which is populated based on engine speed and engine demand torque (e.g., driver demand torque). Method 2300 proceeds to exit.

In this way, the pressure in the engine's intake manifold can be regulated to improve cylinder reactivation and combustion in engine cylinders so that fuel consumption can be reduced and catalyst balance (e.g., the balance between hydrocarbons and oxygen in the catalyst) can be restored, with less fuel being provided to the engine and/or catalyst.

Now with reference to 24 a sequence for operating an engine according to the method of 23 The vertical lines at time points T2400-T2408 represent relevant time points in the sequence. 24 shows six representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 24 is a plot of a deceleration fuel cut-off condition versus time. The vertical axis represents the deceleration fuel cut-off condition. The engine is in deceleration fuel cut-off mode when the trace is at a higher level near the vertical axis arrow. The engine is not in deceleration fuel cut-off mode when the trace is at a lower level. higher level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 24 is a plot of absolute engine manifold pressure (MAP) versus time. The vertical axis represents MAP, and MAP increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The horizontal line 2402 represents a desired MAP during the deceleration fuel cut-off mode.

The third representation from the top in 24 is a plot of engine throttle position versus time. The vertical axis represents engine throttle position, and engine throttle position increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 24 is a plot of the state of the vacuum source versus time. The vertical axis represents the operating state of the vacuum source (e.g., operating state of the vacuum pump), and the vacuum source is turned on when the trace is near the vertical axis arrow. The vacuum source is not turned on when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 24 is a plot of the fuel supply state versus time. The vertical axis represents the fuel supply state, and fuel is supplied to the engine cylinders when the trace is near the vertical axis arrow. Fuel is not supplied to the engine cylinders when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 24 is a plot of the vacuum pickup state versus time. The vertical axis represents the vacuum pickup state, and the vacuum pickup state is on when the trace is near the vertical axis arrow. The vacuum pickups are not on when the trace is near the horizontal axis. Vacuum pickups are not in pneumatic communication with the engine intake manifold when the trace for the vacuum pickup is at a lower level. Vacuum pickups are in pneumatic communication with the engine intake manifold when the trace for the vacuum pickup is at a higher level. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T4200, the engine is not in deceleration fuel cut-off mode, indicated by the deceleration fuel cut-off state at a lower level. The engine MAP is relatively high, indicating a higher engine load. The throttle position is largely open, and the vacuum device state is off, indicating that the vacuum source is not engaged. Fuel is being supplied to engine cylinders, indicated by the high fuel state. The vacuum pickups are operating and capable of tapping vacuum based on the vacuum pickup state.

At time 2402, the engine transitions to the deceleration fuel cut-off mode, indicated by the desired fuel cut-off state trace increasing from a lower level to a higher level. The engine may enter the deceleration fuel cut-off mode in response to a reduction in driver demand torque and the vehicle speed being above a threshold. The throttle is also closed in response to entering the deceleration fuel cut-off mode. Likewise, fuel flow to engine cylinders is shut off, indicated by the fuel state trace being at a lower level. The vacuum pickup state decreases to a lower level to indicate that the vacuum pickups are blocked from receiving vacuum from the engine intake manifold. By blocking the airflow from vacuum pickups into the engine intake manifold, the pressure in the intake manifold can be reduced so that a large amount of fuel is not required to restart the engine with stoichiometric air-fuel ratios in engine cylinders. The cylinder valves are opened in response upon entry into the deceleration fuel cut-off mode. A total actual number of intake valve opening events may be performed in response to activation of the deceleration fuel cut-off mode before stopping airflow through engine cylinders by closing cylinder intake valves over one or more engine cycles while the engine continues to rotate. The total actual number of intake valve opening events may be a number that provides a desired pressure in the engine intake manifold. In some examples, engine intake valves and exhaust valves may be closed over an engine cycle in response to activation of a deceleration fuel cut-off mode.

Between 2402 and 2404, the MAP is reduced and the engine remains in fuel cut-off mode for deceleration. The MAP is reduced to a level of the desired MAP 2402. In one example, the MAP is reduced to a desired MAP 2402 by opening cylinder intake valves an actual total number of times based on an estimate of intake manifold pressure reaching 2402.

At 2404, the MAP increases to a level above 2402 due to air leakage from the engine throttle or other airflow into the engine intake manifold. The vacuum source is turned on in response to the increased MAP, lowering the MAP to 2402. The engine remains in deceleration fuel cut-off mode and the throttle remains closed. The engine continues to rotate (not shown) and fuel flow to the engine cylinders is stopped. The cylinder intake valves remain deactivated and closed (not shown) through each engine cycle. The vacuum source is turned off in response to the MAP being lower than 2402, shortly after it is turned on. The vacuum source state indicates the ON and OFF states of the vacuum source.

At 2406, the MAP increases a second time to a level above 2402 due to air leakage from the engine throttle or other airflow into the engine intake manifold. The vacuum source is turned on in response to the increased MAP, lowering the MAP to 2402. The engine remains in deceleration fuel cut-off mode and the throttle remains closed. The engine continues to rotate (not shown) and fuel flow to the engine cylinders is stopped. The cylinder intake valves remain deactivated and closed (not shown) through each engine cycle. The vacuum source is turned off in response to the MAP being lower than 2402, shortly after it is turned on. The vacuum source state indicates the ON and OFF states of the vacuum source.

At time T2408, the engine exits the deceleration fuel cut-off mode while intake manifold pressure is low. The engine may exit the deceleration fuel cut-off mode in response to an increase in driver demand torque. The lower intake manifold pressure may reduce the use of spark retard and conserve fuel to reactivate engine cylinders and the catalyst in the engine exhaust system. The engine cylinders are reactivated by delivering fuel to the cylinders and reactivating cylinder valves (not shown). The vacuum pickups are also reactivated by enabling communication between the vacuum pickups and the engine intake manifold. MAP increases as the throttle is opened.

In this way, MAP can be controlled during deceleration fuel-cut mode to reduce fuel consumption. Furthermore, powertrain torque disturbances can be reduced because the engine is started with a lower air charge compared to starting with atmospheric pressure in the engine intake manifold.

At this point, 25 which shows a method for controlling absolute engine intake pressure during cylinder reactivation after entering a deceleration fuel cut-off mode. The method according to 25 can be integrated into the system that is 1A-6C The procedure according to 25 may be contained as executable instructions stored in non-volatile memory. The method according to 25 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 2502, method 2500 judges whether the cylinders and valves are deactivated during a deceleration fuel cut-off mode. In one example, method 2500 may judge that engine cylinders are deactivated (e.g., not combusting air and fuel mixtures while the engine is rotating) and valves are deactivated (e.g., held closed, not opening and closing while the engine is rotating over an engine cycle) if a bit in memory is a predetermined value. Note that all or only a portion of the engine cylinders may be deactivated. If method 2500 judges that the engine cylinders and valves are deactivated during the deceleration fuel cut-off mode, the answer is yes, and method 2500 proceeds to 2504. Otherwise, the answer is no, and method 2500 proceeds to 2540.

At 2540, method 2500 operates engine cylinders and valves to provide a desired torque. The desired torque may be based on an accelerator pedal position or a torque determined by a controller. The engine cylinders are turned on by supplying fuel to the cylinders. The valves are turned on by activating valve actuators. Further, volumetric efficiency actuators are adjusted to different positions than at 2508 for a same engine speed and torque demand to improve vehicle emissions and fuel economy. Method 2500 proceeds to end.

At 2504, method 2500 judges whether cylinder reactivation is requested. Cylinder reactivation may be requested in response to an increase in driver demand torque or a vehicle speed below a threshold speed. If method 2500 judges that cylinder reactivation is requested, the answer is yes and method 2500 proceeds to 2506. Otherwise, method 2500 proceeds to 2550.

At 2550, procedure 2500 maintains the cylinders in a deactivated state. The cylinders are not supplied with fuel, and the cylinder valves remain deactivated. Procedure 2500 proceeds to the end.

At 2506, method 2500 judges whether the engine intake manifold pressure exceeds a desired threshold pressure. If the engine intake manifold pressure is above a threshold pressure, engine cylinders may produce more torque than desired, or spark timing may be retarded to reduce engine torque. If the engine intake manifold pressure is greater than desired, cylinders may burn more fuel than desired to provide stoichiometric exhaust gases. Therefore, it may be desirable to reduce the engine intake manifold pressure as early as possible when deactivating engine cylinders so that fuel can be conserved. If method 2500 judges that the intake manifold pressure exceeds the threshold pressure, the answer is yes and method 2500 proceeds to 2508. Otherwise, the answer is no and method 2500 proceeds to 2520. The limit pressure can vary with engine speed, vehicle speed and ambient pressure.

At 2520, method 2500 adjusts engine volumetric efficiency actuators and engine throttle based on engine speed and driver demand torque. In one example, the driver demand torque is based on accelerator pedal position and vehicle speed. The engine volumetric efficiency actuators may include, but are not limited to, engine camshafts, charge motion control valves, and variable plenum volume valves. The positions of the volumetric efficiency actuators may be empirically determined and stored in a table in memory that is populated via driver demand torque and engine speed. Different tables output different positions for the camshafts, charge motion control valves, and variable plenum volume valves. Method 2500 proceeds to 2522.

At 2522, method 2500 reactivates the engine cylinders and cylinder valves. The cylinders are reactivated by supplying fuel and spark to the cylinders. The cylinder poppet valves are reactivated by sequence valve actuators. The valve actuators may be part of a sequence as described in 5B shown arrangement, other valve actuators described herein, or other known valve actuators. Activating the valve actuators causes the intake valves to open and close during an engine cycle. After the engine cylinders are activated, method 2500 proceeds to exit.

At 2508, the method 2500 orders engine volumetric efficiency actuators to increase the engine volumetric efficiency before reactivating engine cylinders and valves. The volumetric efficiency actuators are arranged to increase engine volumetric efficiency at the current engine speed and current driver demand torque, compared to adjusting the volumetric efficiency actuators in response to engine speed and driver demand torque. In one example, cylinder charge motion control valves are fully opened to reduce resistance to flow entering the engine cylinders. Further, intake valve timing and exhaust valve timing are adjusted via camshaft timing to provide no intake valve and exhaust valve overlap (e.g., opening intake and exhaust valves simultaneously). Further, intake valve timing may be advanced or retarded to maximize air in the cylinder at the time of intake valve closure. The variable plenum volume valve is adjusted to minimize intake manifold volume. Engine throttle is not adjusted when adjusting the engine volumetric efficiency actuators. Engine boost pressure may also be increased to increase engine volumetric efficiency via closing a turbocharger wastegate or bypass valve. Method 2500 proceeds to 2510 after the engine volumetric efficiency actuators are adjusted.

At 2510, procedure 2500 reactivates the engine cylinders and cylinder valves. The cylinders are reactivated by supplying fuel and spark to the cylinders. The cylinder poppet valves are reactivated by reactivation valve actuators. The valve actuators may be part of a 5B shown arrangement, other valve actuators described herein, or other known valve actuators. Activating the valve actuators causes the intake valves to open and close during an engine cycle. After activating the engine cylinders, method 2500 proceeds to 2512.

At 2512, method 2500 judges whether the engine intake manifold pressure is at a desired pressure. The desired pressure may be determined empirically and based on engine speed and driver demand torque. If method 2500 judges that the engine intake manifold pressure is at the desired engine intake manifold pressure, the answer is yes and method 2500 proceeds to 2514. Otherwise, the answer is no and method 2500 returns to 2512.

At 2514, method 2500 arranges engine volumetric efficiency actuators and engine throttle based on engine speed and driver demand torque. The positions of the volumetric efficiency actuators may be determined empirically and stored in a table in memory that is maintained based on driver demand torque and engine speed. Different tables output different positions for the camshafts, charge motion control valves, and variable plenum volume valves. Method 2500 proceeds to the end.

Now with reference to 26 a sequence for operating an engine according to the method of 25 The vertical lines at time points T2600-T2405 represent relevant time points in the sequence. 26 shows six representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 24 is a plot of cylinder deactivation request versus time. The vertical axis represents the cylinder deactivation request. Cylinder deactivation is requested when the cylinder deactivation request trace is at a higher level near the vertical axis arrow. Cylinder deactivation is not requested when the cylinder deactivation request trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The first representation from above in 26 is a plot of the cylinder state versus time. The vertical axis represents the cylinder state. The cylinder is turned off when the cylinder state trace is at a lower level near the horizontal axis. The cylinder is not turned off when the cylinder state trace is at a higher level near the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 26 is a plot of engine intake manifold pressure versus time. The vertical axis represents engine intake manifold pressure, and engine intake manifold pressure increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The horizontal line 2602 represents a desired pressure in the engine intake manifold during a deceleration shutdown. The level at 2602 may represent the same pressure as when the engine is operating at idle speed and there is no driver demand torque.

The fourth representation from the top in 26 is a plot of the state of the engine's volumetric efficiency actuator versus time. The vertical axis represents the state of the engine's volumetric efficiency actuator, and the engine's volumetric efficiency actuator increases the engine's volumetric efficiency in the direction of the vertical axis arrow. The state of the engine's volumetric efficiency actuator decreases the engine's volumetric efficiency when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 26 is a plot of engine throttle position versus time. The vertical axis represents engine throttle position, and the amount of throttle opening increases as the trace is closer to the vertical axis arrow. The amount of engine throttle opening decreases as the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 26 is a plot of driver demand torque versus time. The vertical axis represents driver demand torque, and driver demand torque increases toward the vertical axis. Driver demand torque decreases when the driver demand torque trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T2600, the cylinder deactivation request is not asserted, and the cylinder state is asserted to indicate that engine cylinders are on and combusting air and fuel. The engine intake manifold pressure is at a higher level, and the engine throttle position is open more than a midpoint. The engine volumetric efficiency actuators (e.g., camshafts, charge motion control valves, and variable plenum volume valves) are in the midpoint position to provide a midpoint level of engine volumetric efficiency. The driver demand torque is at a midpoint.

At time T2601, the cylinder deactivation request is asserted. The cylinder deactivation request is asserted in response to a decrease in driver demand torque, and the engine may be in fuel cut-off mode for deceleration. The engine throttle position is also decreased in response to the decrease in driver demand torque. The cylinder state transitions to unasserted to indicate that engine cylinders are being deactivated in response to the cylinder deactivation request. The pressure in the engine intake manifold decreases in response to the throttle closing. The cylinder intake valves of cylinders are closed after the throttle closes and after an actual total number of cylinder intake events have reduced the pressure in the intake manifold to a desired level 2602. The cylinder exhaust valves may also be closed (not shown). The engine intake valves are held closed for one or more engine cycles when the cylinders are deactivated. Fuel flow to the cylinders is also shut off (not shown). The position of the engine volumetric efficiency actuators remains unchanged.

Between time T2601 and time T2602, the engine's intake manifold pressure (MAP) increases in response to air escaping into the engine intake manifold. Air is not evacuated from the engine intake manifold because the cylinder intake valves are closed. The cylinder deactivation request remains asserted, and the cylinders remain deactivated. The throttle position remains in a fully closed state, and driver demand remains low.

At time T2602, the position of the engine volumetric efficiency actuators is adjusted to increase the engine volumetric efficiency in anticipation of the reactivation of engine cylinders. The engine volumetric efficiency actuators are not adjusted to positions based on engine speed and driver demand torque. Rather, they are adjusted to positions that increase the engine volumetric efficiency beyond the engine volumetric efficiency positions that the actuators provide when adjusted in response to engine speed and driver demand torque. In this example, the position of volumetric efficiency actuators is adjusted in response to the pressure in the engine intake manifold reaching a desired pressure in the intake manifold of the engine exceeds 2602. By adjusting the volumetric efficiency actuators in response to MAP, undesirable changes in the positions of the volumetric efficiency actuators can be avoided. The pressure in the engine intake manifold increases from a pressure below 2602 to a pressure above 2602. However, the engine volumetric efficiency actuators can be adjusted for a predetermined period of time after cylinders are deactivated or in response to a request to reactivate engine cylinders. Alternatively, the position of the engine volumetric efficiency actuators can be adjusted to increase engine volumetric efficiency in response to the cylinder deactivation request. In one example, camshaft timing is advanced or retarded to maximize the air introduced from the engine intake manifold into engine cylinders (e.g., camshaft timing is adjusted to provide higher cylinder pressure at the time of intake valve closure). Furthermore, the overlap between the intake valve opening and exhaust valve opening is set to zero or negative to reduce airflow into the cylinder from the exhaust system (not shown). The engine throttle position and driver demand torque remain unchanged.

At time T2603, the cylinder deactivation request is transitioned to unasserted in response to an increase in driver demand torque. The cylinder deactivation request may transition to unasserted in response to an increase in driver demand torque or a vehicle speed that is below a threshold speed (not shown). Shortly thereafter, the engine cylinders are re-enabled (e.g., intake and exhaust valves open and close each engine cycle, and spark and fuel are combusted within the engine cylinders), indicated by the cylinder state transitioning to the cylinder-on indication. Further, the position of the volumetric efficiency actuators is adjusted to a position based on engine speed and driver demand torque. The throttle position shifts in response to the driver demand torque.

Between time T2603 and time T2604, driver demand torque increases and then decreases. The throttle position also increases and decreases in response to driver demand torque. The engine intake manifold pressure increases and then decreases below 2602.

At time T2604, cylinder deactivation is requested a second time. However, because the engine intake manifold pressure is below level 2602, the position of the volumetric efficiency actuators is not adjusted. The engine cylinders are deactivated (e.g., combustion in the cylinders is inhibited by stopping fuel flow and spark delivery to the cylinders, and cylinder valves are also deactivated, keeping them closed for one or more engine cycles), as indicated by the cylinder state trace transitioning to a lower level.

At time T2605, the cylinder deactivation request transitions to unasserted in response to the vehicle speed being below a threshold (not shown). The engine cylinders are also reactivated, indicated by the cylinder state trace transitioning to a higher level. The volumetric efficiency actuator positions are not adjusted in response to the deactivation request being unasserted because the engine intake manifold pressure is lower than 2602.

In this way, MAP can be regulated when exiting a cylinder deactivation state to save fuel and reduce torque disturbances. The volumetric efficiency actuators are adjusted to increase the amount of air introduced into engine cylinders so that the pressure in the engine's intake manifold is reduced soon after the engine cylinders are reactivated.

At this point, 27A and 27B which shows a method for the engine torque over the course of cylinder modes. The method according to the 27A and 27B can be integrated into the system that is 1A-6C The procedure according to the 27A and 27B can be included as executable instructions stored in non-volatile memory. The method according to the 27A and 27B may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 2702, method 2700 assesses whether there is a request to decrease an actual total number of activated cylinders (e.g., cylinders with valves that open and close during an engine cycle and cylinders that combust air and fuel during an engine cycle). Method 2700 may judge that there is a request to decrease an actual total number of actual cylinders in response to a decrease in driver demand torque, vehicle speed being above a threshold, and/or other conditions. If method 2700 judges that there is a request to decrease an actual total number of active cylinders, the answer is yes and method 2700 proceeds to 2704. Otherwise, the answer is no and method 2700 proceeds to 2714.

At 2704, method 2700 determines a desired advance for volumetric efficiency actuators to decrease an actual total number of activated cylinders. The advance for the volumetric efficiency actuators is a period of time between a time at which positions of volumetric efficiency actuators are adjusted to decrease a total number of activated cylinders and a time at which cylinder deactivation begins. Adjusting the advance time for the volumetric efficiency actuators may smooth engine torque and provide time for the volumetric efficiency actuators to reach desired positions before cylinder deactivation begins, so that the engine does not provide more or less torque than desired. In one example, the advance time is empirically determined and stored in memory.

Further, the advance time value stored in memory may be adjusted based on a difference between the desired cylinder air charge and the actual cylinder air charge during a transition that decreases the actual total number of cylinders activated. The advance time value is retrieved from memory. Method 2700 proceeds to 2706.

At 2706, method 2700 arranges engine volumetric efficiency actuators, including an amount of boost pressure provided by a turbocharger, to increase the engine volumetric efficiency. For example, boost pressure may be increased, charge motion control valves may be fully opened, plenum volume intake valves may be arranged to decrease intake manifold volume, compressor bypass valves may be at least partially closed, and camshaft timing is adjusted to maximize cylinder filling at the time of intake valve closure. Engine boost pressure may be increased via closing a wastegate or closing the compressor bypass valve. Adjusting the positions of engine volumetric efficiency actuators increases the volumetric efficiency of cylinders that remain energized after the actual total number of energized cylinders is decreased. Further, the engine's central throttle is at least partially closed at the same time (e.g., simultaneously) that the aforementioned engine volumetric efficiency actuators are adjusted. Closing the central throttle maintains the engine airflow rate while adjusting engine volumetric efficiency actuators to increase engine volumetric efficiency. Method 2700 proceeds to 2708.

At 2708, selected cylinders are deactivated after the lead time expires. The cylinders are deactivated by holding the cylinder's intake valves closed for one or more engine cycles while the engine is rotating. In some examples, exhaust valves of the cylinders being deactivated may also be held closed for one or more engine cycles while the engine is rotating. Further, fuel flow and spark are not delivered to cylinders being deactivated. While the cylinders are deactivated, the central throttle is snapped open and fueling is increased to activated cylinders such that torque generated by activated cylinders counteracts torque loss due to cylinder deactivation. Method 2700 proceeds to 2710.

At 2710, method 2700 adjusts spark timing in response to an error between a desired engine airflow and an actual engine airflow. The desired engine airflow is the engine airflow based on the driver demand torque at the time of the cylinder deactivation request. The actual engine airflow is the airflow measured using an airflow sensor. For example, if the actual engine airflow is greater than the desired engine airflow, the engine airflow error is negative and spark timing is retarded to maintain engine torque. If the actual engine airflow is less than the desired engine airflow, the engine airflow error is positive and spark timing is advanced to maintain engine torque. Method 2700 proceeds to 2712.

At 2712, method 2700 assesses whether the engine volumetric efficiency actuators are in their desired positions. For example, method 2700 assesses whether the actual engine boost pressure matches the desired engine boost pressure. Further, method 2700 assesses whether the actual camshaft timing matches the desired camshaft timing. Similarly, Method 2700 determines whether the actual position of the charge motion control valve corresponds to the desired position of the charge motion control valve. Method 2700 may judge that engine volumetric efficiency actuators are at their desired positions based on one or more sensors, such as an intake manifold pressure sensor. If the engine volumetric efficiency actuators are at their desired positions, the answer is yes and method 2700 proceeds to 2714. Otherwise, the answer is no and method 2700 returns to 2706 to provide more time to shift the engine volumetric efficiency actuators.

At 2714, method 2700 adjusts the engine's central throttle to provide a desired engine torque. The desired engine torque may be based on a driver demand torque. Method 2700 proceeds to 2720.

At 2720, method 2700 judges whether there is a request to increase an actual total number of activated cylinders (e.g., cylinders with valves that open and close during an engine cycle and cylinders that combust air and fuel during an engine cycle). Method 2700 may judge that there is a request to increase an actual total number of actual cylinders in response to an increase in driver demand torque, vehicle speed being below a threshold, and/or other conditions. If method 2700 judges that there is a request to increase an actual total number of activated cylinders, the answer is yes and method 2700 proceeds to 2722. Otherwise, the answer is no and method 2700 proceeds to exit.

At 2722, the engine commands engine volumetric efficiency actuators, including an amount of boost pressure provided by a turbocharger, to decrease the engine volumetric efficiency. For example, boost pressure may be decreased, charge motion control valves may be at least partially closed, plenum volume intake valves are commanded to increase intake manifold volume, and camshaft timing is adjusted to reduce cylinder filling at the time of intake valve closure. Adjusting the positions of engine volumetric efficiency actuators decreases the volumetric efficiency of cylinders that are on before decreasing the actual total number of cylinders on. Further, the engine's central throttle is at least partially opened at the same time (e.g., simultaneously) that the aforementioned engine volumetric efficiency actuators are adjusted. Opening the central throttle maintains the engine airflow rate while adjusting engine volumetric efficiency actuators to decrease the engine volumetric efficiency.

Additionally, in some examples, a time overlap of intake valve and exhaust valve opening of engine cylinders (e.g., activated cylinders and/or cylinders being activated) may be increased in response to a turbocharger wastegate position one cylinder cycle prior to cylinder reactivation. The turbocharger wastegate position may be indicative of exhaust pressure in deactivated cylinders that include exhaust valves that open and close while the cylinder is deactivated. However, in other examples, the amount of overlap may be based on an amount of residual exhaust gas in the cylinder. For example, the amount of overlap may be increased as the amount of residual exhaust gas in the cylinder increases. If the deactivated cylinders include non-deactivation exhaust valves, boost pressure may be reduced less than if the cylinder is designed with deactivation exhaust valves because the exhaust density in non-deactivation cylinders may be higher for all other things being equal, as the exhaust in non-deactivation cylinders may be cooler. Procedure 2700 goes to 2724.

At 2724, selected cylinders are re-enabled. The cylinders are re-enabled by opening and closing intake valves of the cylinders over one or more engine cycles while the engine is rotating. In some examples, the exhaust valves of the re-enabled cylinders may also be opened and closed over one or more engine cycles while the engine is rotating. Further, fuel flow and spark are delivered to cylinders that are re-enabled. As the cylinders are re-enabled, the central throttle is snapped shut and fueling is reduced to energized cylinders such that torque generated by energized cylinders counteracts an increase in torque due to the re-enablement of cylinders. Method 2700 proceeds to 2726.

At 2726, method 2700 adjusts spark timing in response to an error between a desired engine airflow and an actual engine airflow. The desired engine airflow is the engine airflow based on the driver demand torque at the time of cylinder deactivation. requirement. For example, if the actual engine airflow is greater than the desired engine airflow, the engine airflow error is negative and spark timing is retarded to maintain engine torque. If the actual engine airflow is less than the desired engine airflow, the engine airflow error is positive and spark timing is advanced to maintain engine torque. Method 2700 proceeds to 2728.

At 2728, method 2700 judges whether the engine volumetric efficiency actuators are in their desired positions. For example, method 2700 judges whether the actual engine boost pressure matches the desired engine boost pressure. Further, method 2700 judges whether the actual camshaft timing matches the desired camshaft timing. Similarly, method 2700 judges whether the actual position of the charge motion control valve matches the desired position of the charge motion control valve. Method 2700 may judge that volumetric efficiency actuators are in their desired positions based on one or more sensors, such as an intake manifold pressure sensor. If the engine volumetric efficiency actuators are in their desired positions, the answer is yes and method 2700 proceeds to 2714. Otherwise, the answer is no and method 2700 returns to 2706 to provide more time to shift the engine volumetric efficiency actuators.

At 2730, method 2700 adjusts the engine's central throttle to provide a desired engine torque. The desired engine torque may be based on a driver demand torque. Method 2700 proceeds to exit.

In this way, the positions of an engine's volumetric efficiency actuators can be adjusted as the actual total number of active cylinders increases or decreases. By moving the volumetric efficiency actuators at the same time as the engine's central throttle is moved, engine torque disturbances can be reduced and engine fuel consumption can be improved.

At this point, 28A which describes a sequence for operating an engine according to the method according to the 27A and 27B The engine in the sequence is a four-cylinder engine with a firing order of 1-3-4-2. The vertical lines at time points T2800-T2804 represent relevant times in the sequence. 28A shows five representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 28A is a plot of a desired number of activated engine cylinders (e.g., cylinders with intake and exhaust valves opening and closing during an engine cycle, and cylinders in which combustion is occurring) versus time. The vertical axis represents the desired number of activated engine cylinders, and the desired number of activated engine cylinders is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 28A is a plot of an actual number of active engine cylinders (e.g., cylinders with intake and exhaust valves opening and closing during an engine cycle, and cylinders in which combustion is occurring) versus time. The vertical axis represents the actual number of active engine cylinders, and the actual number of active engine cylinders is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 28A is a plot of the position of the engine's volumetric efficiency actuator (e.g., wastegate position for adjusting engine boost pressure, camshaft position, position of the charge motion control valves, position of the plenum actuator) versus time. The vertical axis represents the position of the engine's volumetric efficiency actuator, and the position of the actuator increases the engine's volumetric efficiency in the direction of the vertical axis arrow. The position of the actuator decreases the engine's volumetric efficiency near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 28A is a plot of the central throttle position versus time. The vertical axis represents the central throttle position, and the central throttle position increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 28A is a plot of ignition timing versus time. The vertical axis represents ignition timing, and ignition timing increases in the direction of the vertical axis arrow. The ignition timing is retarded near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T2800, the desired actual total number of engine cylinders is four and the actual total number of active cylinders is four. The engine's volumetric efficiency actuators are positioned to provide a lower level of volumetric efficiency. For example, a wastegate is opened to reduce boost pressure, cam timing is advanced to reduce cylinder filling, a plenum valve is positioned to increase intake manifold volume, and the charge motion control valves are closed to decrease volumetric efficiency. The engine throttle is partially open, and spark timing is advanced to a midpoint.

At time 2801, the desired actual total number of active cylinders transitions from four to two. The desired actual total number of active cylinders may be reduced in response to the reduction in driver demand torque (not shown) or other conditions. The actual total number of active cylinders remains at a value of four because no cylinder was deactivated in response to the desired actual total number of active cylinders. The volumetric efficiency actuator position provides a low level of engine volumetric efficiency, and the throttle position is at a medium level. Spark timing is advanced to a medium level.

Between time T2801 and time T2802, the position of the volumetric efficiency actuator is changed to increase the engine's volumetric efficiency, and the throttle begins to close. The desired total number of cylinders fired and the actual total number of cylinders fired remain constant. The ignition timing also remains constant.

At time T2802, spark timing is retarded in response to an error between the actual engine airflow being greater than a desired engine airflow. By retarding spark timing, engine torque is shortened, allowing engine torque to be held constant. The position of the volumetric efficiency actuator continues to change to increase the engine volumetric efficiency, and the throttle begins to close. The desired actual total number of cylinders fired and the actual total number of cylinders fired remain constant.

At time T2803, the cylinder valves are deactivated. The cylinder valves can be deactivated via 5B described valve actuators, other valve actuators described herein, or other known valve actuators may be deactivated. In one example, valve actuators are deactivated to deactivate cylinder intake valves. Cylinder exhaust valves may also be deactivated. The throttle position is increased to open the throttle, allowing additional air to flow into the two cylinders that remain activated. Increasing the throttle position increases intake manifold pressure (MAP), which increases airflow into the activated engine cylinders. Airflow to the deactivated cylinders is terminated when the intake valves of the cylinders to be deactivated are deactivated and held closed. Spark timing begins to be retarded as the air charge of activated cylinders increases. The engine volumetric efficiency actuator does not change position, and the desired actual total number of activated cylinders remains at a value of two. The actual total number of activated cylinders also remains two because no engine cylinders were deactivated.

At time T2804, the actual total number of active cylinders changes from four to two. The intake valves of two cylinders (e.g., cylinders 2 and 3) are deactivated (not shown), and the throttle position remains constant. Spark timing no longer changes, and the engine's volumetric efficiency actuator does not change its position.

In this way, the positions of the volumetric efficiency actuators and engine throttle can be adjusted before cylinder valves are deactivated, thus consuming less fuel during cylinder mode transitions. Furthermore, spark timing can be adjusted in response to a cylinder air charge error instead of in response to a change in engine throttle position, allowing for a smaller spark retard.

At this point, 28B which describes a sequence for operating an engine according to the method according to the 27A and 27B The engine in the sequence is a four-cylinder engine with a firing order of 1-3-4-2. The vertical lines at time points T2820-T2823 represent relevant points in the sequence. 28B shows five representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 28B is a plot of a desired number of activated engine cylinders (e.g., cylinders with intake and exhaust valves opening and closing during an engine cycle, and cylinders in which combustion is occurring) versus time. The vertical axis represents the desired number of activated engine cylinders, and the desired number of activated engine cylinders is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 28B is a plot of an actual number of active engine cylinders (e.g., cylinders with intake and exhaust valves opening and closing during an engine cycle, and cylinders in which combustion is occurring) versus time. The vertical axis represents the actual number of active engine cylinders, and the actual number of active engine cylinders is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 28B is a plot of the position of the engine's volumetric efficiency actuator (e.g., wastegate position for adjusting engine boost pressure, camshaft position, position of the charge motion control valves, position of the plenum actuator) versus time. The vertical axis represents the position of the engine's volumetric efficiency actuator, and the position of the actuator increases the engine's volumetric efficiency in the direction of the vertical axis arrow. The position of the actuator decreases the engine's volumetric efficiency near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 28B is a plot of the central throttle position versus time. The vertical axis represents the central throttle position, and the central throttle position increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 28B is a plot of ignition timing versus time. The vertical axis represents ignition timing, and ignition timing increases in the direction of the vertical axis arrow. The ignition timing is retarded near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T2820, the desired actual total number of engine cylinders is two and the actual total number of active cylinders is two. The engine's volumetric efficiency actuators are positioned to provide a higher level of volumetric efficiency. For example, a wastegate is closed to increase boost pressure, cam timing is retarded to increase cylinder filling, a plenum valve is positioned to reduce intake manifold volume, and charge motion control valves are opened to increase volumetric efficiency. The engine throttle is partially open, and spark timing is advanced to a lower intermediate level.

At time 2821, the desired actual total number of cylinders on transitions from two to four. The desired actual total number of cylinders on may be increased in response to the increase in driver demand torque (not shown) or other conditions. The actual total number of cylinders on remains at a value of two because no cylinder has been re-energized in response to the desired actual total number of cylinders on. The volumetric efficiency actuator position provides a higher level of engine volumetric efficiency, and the throttle position is at a mid-level. Spark timing is advanced to a lower mid-level.

Between time T2821 and time T2822, the position of the volumetric efficiency actuator is changed to reduce the engine's volumetric efficiency, and the throttle begins to open. The desired total number of cylinders fired and the actual total number of cylinders fired remain constant. The ignition timing is constant.

At time T2822, the re-connection of cylinder valves begins. The cylinder valves can be 5B described valve actuators, other valve actuators described herein, or other known valve actuators are re-energized. In one example, valve actuators are re-energized to re-energize cylinder intake valves. Cylinder exhaust valves may also be re-energized. The throttle position is reduced to close the throttle, so less air flows into the two cylinders that are on. By reducing the throttle position, intake manifold pressure (MAP) decreases, reducing airflow into the on-engine cylinders. Air flows into the re-energizing cylinders as the intake valves of the cylinders being re-energized open and close. Spark timing begins to advance as the air charge of on-engine cylinders decreases. The engine volumetric efficiency actuator does not change position, and the desired actual total number of on-engine cylinders remains at a value of four. The actual total number of on-engine cylinders remains two because no engine cylinders were re-energized.

At time T2823, the actual total number of cylinders activated changes from two to four. The intake valves of two cylinders (e.g., cylinders 2 and 3) are activated again (not shown), and the throttle position remains constant. The ignition timing no longer changes, and the engine's volumetric efficiency actuator does not change its position.

In this way, the positions of the volumetric efficiency actuators and engine throttle can be adjusted before cylinder valves are re-energized, thus consuming less fuel during cylinder mode transitions. Furthermore, spark timing can be adjusted in response to a cylinder air charge fault instead of in response to a change in engine throttle position, allowing for a smaller spark retard.

At this point, 29 which shows a method for controlling engine fuel injection during cylinder reactivation after entering a cylinder deactivation mode. The method according to 29 can be integrated into the system that is 1A-6C The procedure according to 29 may be contained as executable instructions stored in non-volatile memory. The method according to 29 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 2902, method 2900 judges whether one or more engine cylinders are deactivated (e.g., intake valves are held closed over an engine cycle as the engine rotates, and no combustion occurs in the deactivated cylinders). In one example, method 2900 may judge that one or more cylinders are deactivated based on a value of a variable stored in memory or an output from one or more sensors. If method 2900 judges that one or more engine cylinders are deactivated, the answer is yes and method 2900 proceeds to 2904. Otherwise, the answer is no and method 2900 proceeds to 2903.

At 2903, method 2900 operates engine cylinders and valves to provide a desired torque. The desired torque may be based on an accelerator pedal position or a torque determined by a controller. The engine cylinders are turned on by supplying fuel to the cylinders. The valves are turned on by activating valve actuators. Method 2900 proceeds to end.

At 2904, method 2900 judges whether cylinder reactivation is requested. Cylinder reactivation may be requested in response to an increase in driver demand torque or a vehicle speed below a threshold speed. If method 2900 judges that cylinder reactivation is requested, the answer is yes and method 2900 proceeds to 2906. Otherwise, method 2900 proceeds to 2905.

At 2905, method 2900 maintains the cylinders in a deactivated state. The cylinders are not fueled, and the cylinder valves remain deactivated. Method 2900 proceeds to exit.

At 2906, method 2900 judges whether the engine is operating in a direct fuel injection (DI) only region or whether there is a change in the requested engine torque that exceeds a threshold exceeds the specified value. An engine with both port and direct fuel injectors may operate only the direct fuel injector within a first defined engine operating range (e.g., a defined engine speed and torque output range). Similarly, an engine with both port and direct fuel injectors may operate only port fuel injectors within a second defined engine operating range. Further, fuel may be delivered to an engine via port and direct fuel injectors in some engine operating ranges. The method determines the engine speed and torque and then determines whether the engine is operating in a range where only direct fuel injection is enabled. If yes, the answer is yes and method 2900 proceeds to 2908. Otherwise, the answer is no and method 2900 proceeds to 2920.

At 2920, method 2900 turns on one or more engine cylinders via supplying spark and fuel to the deactivated cylinders. Additionally, valves of the deactivated cylinders that have been held closed for one or more engine cycles are turned on to open and close over an engine cycle. Fuel is injected into the cylinders via port fuel injectors because the engine is operating in a direct injection only engine operating region and because the rate of change of requested engine torque is below the threshold. After turning on one or more deactivated cylinders, method 2900 proceeds to exit.

At 2908, method 2900 reactivates one or more engine cylinders by reactivating the cylinder valves and supplying fuel, air, and spark to the deactivated cylinders. The engine cylinders are reactivated so that the valves, which were held closed for one or more engine cycles, open and close during one or more engine cycles. The previously deactivated cylinders are fueled by injecting fuel directly into the cylinders.

Direct injection offers the ability to combust air and fuel in previously deactivated cylinders sooner than port fuel injection, as direct fuel injectors can inject fuel during a compression stroke of a cylinder cycle (e.g., later in the cylinder cycle), whereas a port fuel injector must inject fuel during an intake stroke of the cylinder cycle or earlier to support combustion during the cylinder cycle. Therefore, if cylinder reactivation is requested after a cylinder's intake stroke, fuel can be injected during the cylinder's compression stroke to support combustion in the cylinder during the compression stroke. In this way, direct injection may enable combustion in a deactivated cylinder in less than 180 degrees of crankshaft rotation from the degree of crankshaft rotation where cylinder activation is requested, wherein port fuel injection to a previously deactivated cylinder may be more than 180 degrees of crankshaft rotation from the degree of crankshaft rotation where cylinder activation is requested to participate in combustion.

If the cylinder is operating in a region where fuel is only injected into the cylinders via a port, except during engine cycles in which the cylinders are reactivated, the cylinders may be reactivated by injecting fuel directly into the cylinders for a predetermined number of engine cycles or cylinder intake events. Port fuel injection may be reactivated in the recently reactivated cylinders after the predetermined number of engine cycles or cylinder intake events in which direct fuel injection to the recently reactivated cylinders is terminated. In this way, the previously deactivated cylinders may start sooner, and direct injection to the cylinders may be terminated after the predetermined number of engine cycles or cylinder intake events, allowing mixture preparation in the cylinders to improve shortly after the cylinders are reactivated. This may be particularly desirable during conditions where the rate of change in requested engine torque exceeds a threshold, allowing the driver to achieve a faster torque response to the driver demand torque.

If the engine is operating in a region where only direct injection is provided to the engine cylinders, direct injection resumes to the deactivated cylinders, and the cylinders operate with enhanced charge cooling. Direct fuel injection may continue in the engine cylinders until engine operating conditions change. Method 2900 proceeds to 2910.

At 2910, method 2900 judges whether it is permissible to inject fuel via a port or if only direct fuel injection (DI) is desired. Port fuel injection may be initiated after a predetermined actual total number of cylinder intake events since the request to activate one or more cylinders. The predetermined actual total number of events ensures that fuel is injected via direct fuel injection into previously deactivated cylinders in a timely manner and that fuel mixture conditioning improves in a timely manner after the deactivated cylinders are reactivated. Alternatively, only direct fuel injection may be desired under the present engine operating conditions. If method 2900 judges that it is permissible to inject fuel via a port or if only direct fuel injection is desired, the answer is yes and method 2900 proceeds to 2912. Otherwise, method 2900 returns to 2908.

At 2912, method 2900 operates direct and port fuel injectors according to a base schedule. The base schedule may be based on engine speed and driver demand torque. Therefore, direct fuel injection may be used to reactivate deactivated cylinders at previous crankshaft angles after the request to activate cylinders, then port fuel injection or port and direct fuel injection may replace only directly injecting fuel. Method 2900 proceeds to exit.

Now with reference to 30 a sequence for operating an engine according to the method of 29 The vertical lines at time points T3000-T3002 represent relevant time points in the sequence. 30 shows three plots, and the plots are aligned in time and occur simultaneously. The SS markers along each plot represent timely braking. Each timely braking can be of long or short duration. Events to the left of the SS markers represent engine operating conditions where fuel is injected only via an intake manifold until the engine cylinders are restarted. Events to the right of the SS markers represent engine operating conditions where fuel is injected only directly. The sequence after 30 is for a four-cylinder engine with a firing order of 1-3-4-2. The three diagrams are aligned according to the crankshaft position.

Example exhaust valve opening times are indicated by the cross-hatched patterns 3002, 3012, 3023, 3028, 3051, 3056, 3064, and 3069. Example intake valve opening times are indicated by the cross-hatched patterns 3004, 3013, 3024, 3029, 3052, 3057, 3065, and 3070. The start of direct fuel injection events is indicated by nozzles 3006, 3053, 3058, 3062, and 3066. Firing events are indicated by the * at 3010, 3015, 3026, 3054, 3059, 3063, and 3067. The start of the port fuel injection processes is indicated by nozzles 3008, 3014, 3021 and 3025.

The first representation from above in 30 is a plot of engine events versus engine position for cylinder number three. Engine strokes are shown along the horizontal axis and are designated by the letters I, C, P, and E. I represents an intake stroke. C represents a compression stroke, P represents a power stroke, and E represents an exhaust stroke. Vertical bars separate each stroke and represent top dead center or bottom dead center of piston travel. Port fuel injection windows, such as 3001 and 3011, are referred to as PFI. Fuel may be injected into a cylinder via port fuel injectors during the port fuel injection window for one cylinder cycle. Port injection of fuel outside the port fuel injection window supplies fuel to another cylinder cycle. Direct fuel injection into cylinders can occur during the intake and compression strokes.

The second illustration from the top in 30 is a plot of engine events versus engine position for cylinder number two. Engine strokes are represented along the horizontal axis and denoted by the letters I, C, P, and E. I represents an intake stroke. C represents a compression stroke, P represents a power stroke, and E represents an exhaust stroke. Vertical bars separate each stroke and represent the top dead center or bottom dead center of the piston travel.

The third plot is a representation of a cylinder deactivation request state versus engine position. The vertical axis represents the cylinder reactivation state, and cylinder reactivation is requested when the trace is near the height of the vertical axis arrow. The cylinder reactivation state does not request cylinder reactivation when the plot trace is near the horizontal axis. In some Examples include replacing the cylinder reactivation request with a variable for a requested number of activated cylinders.

At time T3000, cylinders two and three are deactivated (e.g., fuel is not injected into the cylinders and the intake and exhaust valves of the cylinders are maintained in a closed state for one engine cycle), and the cylinder reactivation request is not acknowledged. Consequently, no fuel is injected into cylinders two and three. Further, the intake and exhaust valves of cylinders two and three are maintained closed. Cylinders one and four are mixtures of combusting air and combusting fuel (not shown) while the engine is rotating.

At time T3001, a request to reactivate the engine cylinders is made, indicated by the cylinder reactivation request transitioning to a higher level. The cylinder reactivation request occurs halfway through the port fuel injection (PFI) window 3001 and may be due to an increase in driver demand torque. Because the port fuel injector must precisely provide smaller amounts of fuel and larger amounts of fuel, the flow rate is such that it cannot provide sufficient fuel to provide a stoichiometric mixture in cylinder number three during the port fuel injection window 3001. For this reason, fuel is directly injected so that combustion can begin in cylinder number three as soon as possible after the cylinder reactivation request. Fuel is directly injected after the first intake stroke following time T3001. The fuel injected at 3006 is combusted at 3010.

The cylinder reactivation request occurs at the end of port fuel injection window 3020, before deactivated intake and exhaust valves begin operating. Port fuel injection begins at 3021 at the beginning of port fuel injection window 3022, allowing the number two cylinder port fuel injector sufficient time to inject an amount of fuel to create a stoichiometric mixture in cylinder number two. Fuel is not directly injected into cylinder number two because the cylinder reactivation request occurs too late in the compression stroke to directly inject a desired amount of fuel.

Fuel is injected via a manifold into cylinder number three for a second combustion event in cylinder number three at 3008. Fuel is injected via a manifold at the beginning of the port fuel injection window 3011 so that a stoichiometric mixture can be provided to cylinder number three. The fuel injected at 3008 is introduced into cylinder number three when the intake valve is open at 3013. The second combustion event occurs in cylinder number three at 3015.

Fuel is injected via a port into cylinder number two for a second combustion event in cylinder number two at 3025. Fuel is injected via a port at the beginning of the port fuel injection window 3027 so that a stoichiometric mixture can be provided in cylinder number two. The fuel injected at 3025 is introduced into cylinder number two when the intake valve is open at 3029. The second combustion event occurs in cylinder number three at 3026.

Cylinders two and three are deactivated a second time between the SS markers and time T3002. At this time, no fuel is injected and no combustion occurs in the cylinders. Cylinders one and four combust air and fuel while the engine is rotating (not shown). No re-cylinder activation is requested.

At time T3002, cylinder reactivation is asserted a second time. The cylinder reactivation request may be asserted in response to an increase in driver demand torque or other conditions. The engine is operating under conditions where only direct fuel injection is scheduled. Since port fuel injection is not scheduled, the first direct injection occurs since the cylinder reactivation request at 3062. Fuel is injected during a compression stroke of cylinder number two and combusts with air trapped in the cylinder if cylinder number two was deactivated. The injected fuel is combusted in a first combustion event 3063 since the cylinder reactivation request at T3002. However, in some examples, exhaust gas may be trapped in cylinder number two or air may escape via the pistons if cylinder number two is activated for an extended period of time. In these conditions, the first direct fuel injection would be in cylinder number two after cylinder reactivation at 3066, with fresh air being directed into cylinder number two.

A first direct injection for cylinder number three after time T3002 occurs at 3053, after the intake and exhaust valves have been reactivated and opened at 3051 and 3052. The fuel injected at 3053 is combusted at 3054.

A second direct injection into cylinder number two is performed at 3066. Fuel injected at 3066 is combusted with air introduced at 3065. The spark at 3067 initiates the second combustion event in cylinder number two since the cylinder reactivation request at T3002.

A second direct injection into cylinder number three is performed at 3058. Fuel injected at 3058 is combusted with air introduced at 3057. The spark at 3059 initiates the second combustion event in cylinder number three since the cylinder reactivation request at T3002.

In this way, direct fuel injection can reduce the time required to restart engine cylinders that have been deactivated. Furthermore, fuel can be injected via an intake manifold after the engine cylinders have been restarted with direct injection to improve mixing within the engine cylinders, thereby reducing engine emissions.

At this point, 31 which shows a method for controlling an engine oil pump in response to the cylinder mode. The method according to 31 can be integrated into the system that is 1A-6C The procedure according to 31 may be contained as executable instructions stored in non-volatile memory. The method according to 31 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 3102, method 3100 assesses whether there is a request to switch the cylinder intake valves or intake and exhaust valves to a deactivated state. The request may be based on the method of 22 If method 3100 judges that there is a request to switch the cylinder poppet valves to a deactivated state, the answer is yes and method 3100 proceeds to 3104. Otherwise, method 3100 proceeds to 3120.

At 3104, method 3100 determines a minimum oil rail pressure for deactivating the cylinder poppet valves under the present engine operating conditions. In one example, the engine intake and exhaust poppet valves are normally on and are deactivated by supplying pressurized oil to the valve actuators. The pressurized oil deactivates the intake and exhaust valves, keeping the intake and exhaust valves closed for one or more engine cycles. When the pressure of the oil is reduced, the deactivated valves are reactivated to open and close over one engine cycle.

The minimum oil pressure to deactivate the cylinder poppet valves may be determined empirically based on parameters such as engine oil temperature and engine speed. The minimum oil pressure to deactivate the cylinder poppet valves may be stored in a table or function in memory that is entered via the parameters. Method 3100 enters the table or function to determine the minimum oil pressure to deactivate the cylinder poppet valves under the present engine operating conditions and proceeds to 3106.

At 3106, method 3100 determines a minimum oil pressure for lubricating the engine at the current engine operating conditions. The minimum oil pressure for lubricating the engine may be determined empirically based on parameters such as engine oil temperature, engine torque, and engine speed. The minimum oil pressure for lubricating the engine may be stored in a table or function in memory that is accessed via the parameters. Method 3100 accesses the table or function to determine the minimum oil pressure for lubricating the engine at the current engine operating conditions and proceeds to 3108.

At 3108, method 3100 determines a minimum oil pressure for operating time-variable camshafts at the present engine operating conditions. The minimum oil pressure for operating the time-variable camshafts may be determined based on parameters such as engine oil temperature, engine torque and engine speed are determined empirically. The minimum oil pressure for confirming the time-varying camshafts may be stored in a table or function in memory that is entered via the parameters. Method 3100 enters the table or function to determine the minimum oil pressure for confirming the time-varying camshafts at the present engine operating conditions and proceeds to 3110.

At 3110, method 3100 determines a maximum oil pressure from the minimum oil pressures determined at 3104-3108 and adjusts actuators to provide the same value. For example, if the minimum oil pressure for poppet valve deactivation is 100 kPa, the minimum oil pressure to lubricate the engine is 200 kPa, and the minimum oil pressure to adjust the camshaft position relative to the crankshaft position is 150 kPa, where the maximum oil pressure from the minimum oil pressures is 200 kPa. The oil pressure supplied by the oil pump is commanded to be 200 kPa. The resulting oil pressure request is the static oil pressure request. The oil pressure may be adjusted by adjusting the oil pump displacement, the position of a dump valve, or the oil flow through cooling jets. Method 3100 proceeds to 3110.

At 3112, method 3100 issues a command to increase oil pressure in an oil line to the cylinder poppet valve actuators. The oil pressure may be increased by increasing a pump displacement command, reducing flow through an oil line dump valve, reducing flow through piston cooling jets, or increasing the oil pump speed. The oil pressure command is increased to a value greater than a value to maintain the valves in a closed state, so the valves are deactivated quickly. This increase in oil pressure request is the dynamic request. The dynamic command may be determined empirically and stored in a table or field maintained by engine speed and oil temperature. The duration of the dynamic request is relatively short, and the duration of the static request is longer. In this way, the oil pump pressure request may consist of a static request and a dynamic request. Additionally, method 3100 may adjust the oil pressure output from the oil pump in response to oil quality. For example, if oil quality is high, the oil pump pressure may be reduced based on the improved oil lubricity of newer or higher-quality oil. Further, method 3100 may not turn on the cylinder cooling nozzles at the same time as energizing or deactivating cylinders via intake and exhaust valve actuators. Method 3100 proceeds to 3114.

At 3114, method 3100 reduces the oil pressure in the oil line to the value determined at 3110 or to the static oil pressure command once it is determined that the desired cylinder poppet valves are deactivated. Method 3100 proceeds to 3116.

At 3116, method 3100 moves the cylinder poppet valves to the requested state or maintains them in their current state if there is no request to change the cylinder state. Method 3100 proceeds to exit.

At 3120, method 3100 judges whether there is a request to switch the cylinder intake valves, or intake and exhaust valves, to an on state. The request may be based on driver demand torque and/or other vehicle operating conditions. If method 3100 judges that there is a request to switch the cylinder poppet valves to an on state, the answer is yes, and method 3100 proceeds to 3122. Otherwise, method 3100 proceeds to 3114.

At 3122, method 3100 reduces oil pressure in an oil line to the cylinder poppet valve actuators. The oil pressure may be reduced by reducing a pump displacement command, increasing flow through an oil line dump valve, increasing flow through piston cooling jets, or reducing the oil pumping speed. Method 3100 proceeds to 3114.

Now with reference to 32 a sequence for operating an engine according to the method of 31 The vertical lines at time points T3200-T3204 represent relevant time points in the sequence. 32 shows six representations and the representations are aligned in time and occur simultaneously.

The first representation from above in 32 is a representation of a cylinder deactivation request state versus time. The cylinder deactivation request forms the basis for the Cylinders can be turned on and off. Furthermore, cylinder valves can be turned on and off based on the cylinder deactivation request. The vertical axis represents the cylinder deactivation request, and cylinder deactivation is requested when the trace is at a higher level near the vertical axis arrow. Cylinder deactivation is not requested when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 32 is a plot of the cylinder deactivation state versus time. The vertical axis represents the cylinder deactivation state, and one or more engine cylinders are deactivated when the deactivation state trace is at a higher level near the vertical axis arrow. Cylinders are not deactivated when the trace is at a lower level near the horizontal axis. Fuel no longer flows to the deactivated cylinders, and the intake and exhaust valves of deactivated cylinders are held closed for one or more engine cycles, so no combustion occurs in the deactivated cylinders. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 32 is a plot of the engine oil pump displacement command versus time. The vertical axis represents the oil pump displacement command, and the value of the oil pump displacement command increases in the direction of the vertical axis arrow. The engine oil pump displacement command consists of the combined values of the static oil pressure command and the dynamic oil pressure command. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 32 is a plot of static oil pressure demand versus time. The vertical axis represents the static oil pressure demand, and the value of the static oil pressure demand increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 32 is a plot of the dynamic oil pressure command versus time. The vertical axis represents the dynamic oil pressure demand, and the value of the dynamic oil pressure demand increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The sixth representation from the top in 32 is a plot of the engine oil rail pressure command versus time. The vertical axis represents the engine oil rail pressure, and the value of the engine oil rail pressure command increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The horizontal line 3202 represents a minimum oil rail pressure to maintain a deactivated valve in a deactivated state.

At time T3200, cylinder deactivation is not requested and the cylinders are not deactivated. The static oil pressure request is at a lower level, and the oil pump displacement command is at a lower level. The dynamic oil pressure request is zero. The engine oil rail pressure is at a lower level.

At time T3202, the cylinder deactivation request is asserted. The cylinder deactivation request may be asserted in response to a decrease in driver demand torque or other vehicle operating conditions. The cylinder deactivation state indicates that the cylinders are not deactivated. The dynamic oil pressure request increases in response to the cylinder deactivation request. The static oil pressure request also increases in response to the cylinder deactivation request. The oil pump displacement command increases in response to the cylinder re-deactivation request. The oil pump displacement command adjusts the oil pump displacement. The oil rail pressure increases in response to the oil pump displacement command.

Alternatively, an oil rail quick dump valve may be at least partially closed to increase oil rail pressure as shown. Further, in some examples, engine cooling jet flow may be reduced to increase oil rail pressure as shown. Even further, in some examples, oil pump speed is increased to increase oil rail pressure as shown.

At time T3203, the cylinder deactivation state transitions to a higher level to indicate that the cylinder valves will be deactivated and held closed for one or more engine cycles. The cylinder deactivation state may be based on the output of one or more sensors (e.g., valve actuation sensors, exhaust gas sensors, or other sensors). The oil pump displacement command decreases and the dynamic oil pressure command decreases. The static oil pressure request remains at its previous value. The oil rail pressure decreases at an oil pressure slightly above 3202, allowing the valves to remain deactivated and reducing oil pump energy consumption.

At time T3204, the cylinder reactivation request is set by transitioning the cylinder deactivation state to a lower level. Cylinder reactivation may occur in response to an increase in driver demand torque or another vehicle operating condition. The cylinder deactivation state indicates that the cylinders are deactivated. The dynamic oil pressure command is reduced in response to the cylinder reactivation request. The static oil pressure command is also reduced in response to the cylinder reactivation request. The oil pump displacement command decreases in response to the cylinder reactivation request. The oil pump displacement command adjusts the oil pump displacement. The oil rail pressure decreases in response to the oil pump displacement command.

Alternatively, an oil rail quick dump valve may be at least partially opened to reduce oil rail pressure as shown. Further, in some examples, engine cooling jet flow may be increased to reduce oil rail pressure as shown. Even further, in some examples, oil pump speed is reduced to reduce oil rail pressure as shown.

At time T3204, the cylinder deactivation state transitions to a lower level to indicate that the cylinder valves will be reactivated and opened and closed over one or more engine cycles. The cylinder reactivation state may be based on the output of one or more sensors (e.g., valve actuation sensors, exhaust gas sensors, or other sensors). The oil pump displacement command increases and the dynamic oil pressure command increases. The static oil pressure request remains at its previous value. The oil rail pressure decreases to a value corresponding to a maximum oil pressure or a minimum oil pressure for lubricating the engine, with the minimum oil pressure serving to activate the camshafts at a desired rate.

In this way, cylinder and cylinder valve deactivation can be accelerated while reducing the energy consumed by the oil pump. Furthermore, the cylinder valves can be quickly reactivated by incorporating a dynamic oil pressure regulation command.

At this point, 33 which shows a method for controlling engine knock in response to cylinder operating mode. The method according to 33 can be integrated into the system that is 1A-6C The procedure according to 33 may be contained as executable instructions stored in non-volatile memory. The method according to 33 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 3302, method 3300 maps engine knock sensor outputs or assigns engine knock sensor outputs to activated cylinders. Alternatively, method 3300 may map engine knock sensor outputs based on a deactivated cylinder map. For example, knock sensors for a four-cylinder engine with a firing order of 1-3-4-2 and engine knock sensors configured as in 1A shown are positioned according to Table 2. Table 2 Cylinder mode Cylinder deactivation mode 1 2 3 4 5 6 7 FUEL 1.2 1.2 1 2 1 2 1 FUEL AND AIR 1.2 1.2 1.2 1.2 1.2 2 1.2

Table 2 lists two cylinder deactivation modes. The first mode is labeled FUEL and describes a mode in which cylinders are deactivated by stopping the fuel supply to the cylinders while the intake and exhaust valves remain open throughout an engine cycle. net and closed. The second mode is labeled FUEL AND AIR and describes a mode in which cylinders are deactivated by terminating the fuel supply to the cylinders while the intake and exhaust valves are held in a closed state throughout an engine cycle.

The cylinder modes are referred to as 1, 2, 3, 4, 5, 6, and 7. Changes between the different modes can be based on the amount of time the engine is operating in a mode, the amount of oil in deactivated cylinders, the number of engine revolutions in the mode, and other conditions described herein that can result in mode changes between cylinder modes. Mode 1 occurs when cylinders 1-4 are activated (e.g., air and fuel are burning as the valves open and close over an engine cycle) and the engine is rotating due to torque generated by cylinders 1-4. Mode 2 occurs when cylinders 1 and 4 are activated and the engine is rotating due to torque generated by cylinders 1 and 4. Mode 3 occurs when cylinders 1, 4, and 2 are activated and the engine is rotating due to torque generated by cylinders 1, 4, and 2. Mode 4 occurs when cylinders 1, 3, and 4 are switched on and the engine rotates using torque generated by cylinders 1, 3, and 4. Mode 5 occurs when cylinders 3 and 2 are switched on and the engine rotates using torque generated by cylinders 3 and 2. Mode 6 occurs when cylinders 3, 4, and 2 are switched on and the engine rotates using torque generated by cylinders 3, 4, and 2. Mode 7 occurs when cylinders 1, 3, and 2 are switched on and the engine rotates using torque generated by cylinders 1, 3, and 2. Alternatively, cylinder modes can describe cylinders that are switched off.

In this example, the table cells are populated with the values 1 and/or 2, but other values may be used. A value of one indicates that a knock sensor positioned near cylinders 1 and 2 is selected to detect and determine engine knock. A value of two indicates that a knock sensor positioned near cylinders 3 and 4 is selected to interrogate and determine engine knock. For example, if the engine is operating in cylinder mode A with a FUEL cylinder deactivation mode, knock sensors 1 and 2 are selected and interrogated to determine engine knock in cylinders 1-4. On the other hand, when the engine is operating in cylinder mode F with a FUEL AND AIR cylinder deactivation mode, knock sensor 2 is the only knock sensor selected and interrogated to determine engine knock in cylinders 3, 4 and 2.

Table 2 shows that individual engine knock sensors may be assigned to detect knock in different cylinders for different cylinder modes and different cylinder deactivation modes. One engine knock sensor may provide an improved signal-to-noise ratio in one cylinder mode and one cylinder deactivation mode, while another knock sensor may provide an improved signal-to-noise ratio in the one cylinder mode and a second cylinder deactivation mode. Further, engine knock thresholds may be adjusted in response to the knock sensor providing knock data according to the knock sensor assignments. The engine knock sensor or sensors assigned to a particular cylinder mode or cylinder deactivation mode are interrogated during an engine cycle to indicate knock in activated cylinders. An engine knock sensor not assigned to a particular cylinder mode and cylinder deactivation mode is not interrogated, or the values determined for that knock sensor are not used to determine engine knock during an engine cycle. In this way, engine knock sensors can be mapped to improve signal-to-noise ratios. Similar maps can be provided for six- and eight-cylinder engines. Method 33 proceeds to 3304.

At 3304, method 3300 determines which engine cylinders are activated and deactivated. In one example, the activated cylinders are 11 described, determining whether conditions exist to deactivate one or more cylinders. In other examples, activated cylinders may be identified values of variables at specific locations in memory. The values of the variables may be revised each time a cylinder is activated or deactivated. For example, a variable in memory may indicate the operating status of cylinder number one. A value of one in the variable may indicate that cylinder number one is activated, while a value of zero in the variable may indicate that cylinder number one is deactivated. In this way, the operating state of each cylinder may be determined. Method 3300 proceeds to 3306.

At 3306, method 3300 determines which engine cylinders are deactivated by adjusting the fuel flow to the cylinders but not adjusting the airflow to the cylinders. Method 3300 also determines which cylinders are deactivated by adjusting the fuel flow and airflow to the deactivated cylinders. In one example, the controller associates a variable in memory with each cylinder to track the cylinder's deactivation mode. The deactivation mode of a cylinder is stored in the controller's memory when the cylinder is deactivated. For example, a value of a variable is 1 if cylinder number one is deactivated by ceasing fuel flow to the deactivated cylinder number one, but not by ceasing airflow to the deactivated cylinder number one. Conversely, the value of the variable is 0 if cylinder number one is deactivated by ceasing fuel flow and airflow to the deactivated cylinder number one. A cylinder can be deactivated using any of the methods and systems described herein. The values of the variables can be revised each time a cylinder is deactivated.

In some examples, a table similar to Table 2 may be created to output a threshold knock value based on the cylinder mode and the cylinder deactivation mode. The values in the table may be empirically determined and stored in the table. The table is populated via the cylinder mode and the cylinder deactivation mode. The table outputs the threshold knock values against which the knock sensor outputs are compared. If the knock sensor output exceeds the threshold knock value, knock may be determined. Method 3300 proceeds to 3308.

At 3308, method 3300 observes selected knock sensors to determine engine knock. Specifically, knock sensors are selected based on the knock sensor map described at 3302. The map of knock sensors is populated via cylinder mode and cylinder deactivation mode. The table outputs the engine knock sensors that are polled for engine knock in the various cylinder modes and cylinder deactivation modes during an engine cycle. In one example, the knock sensors are monitored at specific crankshaft angular ranges to detect knock in activated cylinders.

If the knock sensor output exceeds a threshold (e.g., the knock thresholds described at 3306), engine knock is indicated. In some examples, the knock sensor output may be integrated and compared to the threshold. If the integrated knock sensor output is greater than the threshold, engine knock is indicated. Method 3300 proceeds to 3310.

At 3310, method 3300 adjusts an actuator in response to the knock indication. In one example, spark timing is retarded to reduce engine knock. The start of fuel injection timing may be retarded to reduce cylinder pressure and engine knock. Alternatively, the amount of injected fuel may be increased. Further, in some cases, cylinder air charge may be reduced to reduce the possibility of engine knock. Additionally, the ratio of an amount of fuel injected via an intake to an amount of directly injected fuel may be adjusted in response to engine knock. For example, the amount of directly injected fuel may be increased, while the amount of port injected fuel may be reduced. Method 3300 proceeds to end after the actuator is adjusted.

Now with reference to 34 a sequence for operating an engine according to the method of 34 The vertical lines at time points T3400-T3407 represent relevant time points in the sequence. 34 shows six representations and the representations are time-aligned and occur simultaneously. The sequence according to 34 represents a sequence for operating a four-cylinder engine at a substantially constant speed and a substantially constant driver demand torque (e.g., torque and speed change of less than 5%).

The first representation from above in 34 is a plot of ignition timing for energized cylinders (e.g., cylinders burning air and fuel) versus time. The vertical axis represents ignition timing for energized cylinders, and the spark is advanced further when the trace is at a higher stage near the vertical axis arrow. The spark is advanced or retarded less when the trace is at a lower stage near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 34 is a plot of the cylinder group turned on versus time. The vertical axis represents the cylinder group turned on, and the cylinder group is turned on when the trace is at the cylinder group level. In this example, there are two possible cylinder groups, A and B, as indicated along the vertical axis. Group 1 indicates that cylinders 1-4 are turned on and burning air and fuel. Group 2 indicates that cylinders 1 and 4 are turned on and burning air and fuel. Cylinders 2 and 3 are turned off when group 3 is turned on. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 34 is a plot of cylinder deactivation mode versus time. The vertical axis represents cylinder deactivation mode. Cylinders are not deactivated when the cylinder deactivation trace is near the midpoint of the vertical axis. Deactivated cylinders are deactivated by stopping the supply of air and fuel to the deactivated cylinders when the trace is near the vertical axis arrow. Deactivated cylinders are deactivated by stopping the supply of fuel to the deactivated cylinders while air flows through the deactivated cylinders when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 34 is a plot showing the knock sensors sampled versus time. The vertical axis represents the knock sensors sampled. A value of one indicates that only the first knock sensor is sampled. A value of two indicates that only the second knock sensor is sampled. Values 1 and 2 indicate that both the first and second knock sensors are sampled. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 34 is a plot of knock sensor output amplitude versus time. The vertical axis represents knock sensor amplitude, and knock sensor output increases in the direction of the vertical axis arrow. Solid line 3404 is the output of the first knock sensor.

Dashed line 3406 is the output of the second knock sensor. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. Dashed line 3402 represents a threshold for comparing the knock sensor output. If the knock sensor output is greater than 3402, engine knock is indicated. The level of 3402 is adjusted for the cylinder group and cylinder deactivation mode.

The sixth representation from the top in 34 is a plot of indicated engine knock versus time. The vertical axis represents the indicated engine knock. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. An engine actuator can be adjusted in response to indicated engine knock to reduce the possibility of further engine knock.

At time T3400, cylinder group 1 is on and spark timing is further advanced. The cylinders are not deactivated, so cylinder deactivation mode indicates no deactivated cylinders. The knock sensors polled are 1 & 2, so the first and second knock sensors are polled to determine if engine knock is present. The outputs of the first and second knock sensors are less than threshold 3402, so no engine knock is indicated.

At time T3401, the active cylinder group transitions to Group 2. Two engine cylinders are deactivated below Group 2 (e.g., cylinders 2 and 3). The active cylinder group may change in response to a reduction in driver demand torque or other changes in vehicle operating conditions (e.g., engine temperature reaching a threshold temperature). Spark timing is retarded to reflect higher load in the two active cylinders, even if driver demand torque has not changed (not shown). The two cylinders are deactivated via deactivating fuel flow to the cylinders. Fuel injection is paused to stop fuel flow to the two cylinders. Air continues to flow through the deactivated cylinders because the cylinder deactivation mode is FUEL. The polled knock sensors remain unchanged. The knock sensor threshold 3402 is reduced to a lower level because the background noise can be reduced since two engine cylinders are inactive and the combustion noise can be reduced. The knock sensor outputs do not exceed threshold 3402, therefore no engine knock is indicated.

At time T3402, the active cylinder group transitions back to Group 1. The active cylinder group may change state in response to an increase in driver demand torque, a reduction in engine temperature, or another condition. The cylinder deactivation mode transitions back to midpoint to indicate no cylinders are deactivated. The polled knock sensors remain unchanged. The knock sensor threshold increases back to its previous level, and no engine knock is indicated because the knock sensor outputs are below threshold 3402. The engine spark timing returns to its previous value.

At time T3403, the active cylinder group transitions back to Group 2. The two cylinders are deactivated by shutting off fuel and air to the cylinders. Fuel injection is stopped to stop fuel flow to the two cylinders, and the intake and exhaust valves of the two deactivated cylinders are held closed for one engine cycle to terminate airflow to the two deactivated cylinders. The polled knock sensors remain unchanged. Knock sensor threshold 3402 is reduced to a minimum level because the background noise caused by the lack of combustion in the deactivated cylinders and deactivation cylinder valves can be reduced by reducing valve influence. The outputs of the first and second knock sensors do not exceed threshold 3402, so no engine knock is indicated. Spark timing is retarded to reflect the increased load on the active cylinders to maintain driver demand torque.

At time T3404, the output of the first knock sensor exceeds threshold 3402. Therefore, engine knock is indicated as shown in the sixth illustration. Spark timing is further retarded in response to the engine knock indication. The on-cylinder group remains 2, and cylinder airflow and fuel flow to the off-cylinders remains paused. The polled knock sensors remain unchanged. The knock sensor output decreases in response to increased spark retard.

At time T3405, the activated cylinder group transitions back to Group 1. The cylinder deactivation mode transitions back to the midpoint to indicate that no cylinders are deactivated. The polled knock sensors remain unchanged. The knock sensor threshold increases back to its initial level, and no engine knock is indicated because the knock sensor outputs are below threshold 3402.

At time T3406, the active cylinder group transitions to group 3. Three cylinders (e.g., cylinder numbers 1, 4, and 2) are active in cylinder group 3. The polled knock sensors transition from 1 & 2 to 1. For this reason, when group 3 is activated and the cylinders are deactivated by stopping fuel flow without stopping airflow to the deactivated cylinders (e.g., FUEL, as shown in Table 2), the first knock sensor is the only knock sensor polled. By switching the polled knock sensors, the signal-to-noise ratio for determining engine knock may be improved. Engine knock is not indicated because the first and second knock sensor output are below threshold 3402.

At time T3407, the activated cylinder group transitions back to Group 1. The cylinder deactivation mode transitions back to the midpoint to indicate that no cylinders are deactivated. The knock sensor threshold increases back to its initial level, and no engine knock is indicated because the output of the first and second knock sensors is below threshold 3402.

In this way, different knock sensors may be interrogated in response to the activated cylinder group and the cylinder deactivation mode. Furthermore, the threshold against which the knock sensor outputs are compared may change in response to the cylinder mode and the cylinder deactivation mode. The cylinder modes, the interrogated knock sensors, the knock thresholds, and the cylinder groups are exemplary in nature and are not intended to limit the scope or breadth of the disclosure.

At this point, 35 which shows a method for controlling engine knock in response to the cylinder deactivation mode. The method according to 35 can be integrated into the system that is 1A-6C The procedure according to 35 can be used as executable instructions stored in non-volatile memory. The method according to 35 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

wobei CYLss die Schätzung einer stationären Zylindertemperatur (z. B. Temperatur eines Zylinders) ist; Cyl_temp_fn die Zylindertemperatur als eine Funktion der Motordrehzahl (N), der Motorlast (L) und des Zylinderabschaltungszustands (CYL d state) ist; AF_fn eine Funktion ist, die einen Multiplikator reeller Zahlen für das Luft-Kraftstoff-Verhältnis im Zylinder bereitstellt (afr); Spk_fn eine Funktion ist, die einen Multiplikator reeller Zahlen für die Zylinderzündung auf der Grundlage der Zündverzögerung für den MBT-Zündzeitpunkt bereitstellt (spkMBT); und EGR_fn eine Funktion ist, die einen Multiplikator reeller Zahlen für den Prozentsatz der Abgasrückführung (EGR) bereitstellt. CYL d state ermittelt, ob der Zylinder angeschaltet ist und Luft und Kraftstoff verbrennt oder nicht Luft und Kraftstoff verbrennt, sodass die Ausgabe CYLss sich ändert, wenn sich der Motorzylinder von angeschaltet zu abgeschaltet oder umgekehrt ändert. Die stationäre Temperatur eines Zylinders wird von einer Zeitkonstante verändert, um die Schätzung der Zylindertemperatur über die folgende Gleichung bereitzustellen: $$CY{L}_{tmp}=CY{L}_0{e}^{\frac{-t}{\tau }}+CYLss\left(1-e^{\frac{-t}{\tau }}\right)$$

wobei CYL_tmp die endgültige geschätzte Zylindertemperatur ist, CYL₀ die anfängliche Zylindertemperatur ist, t die Zeit ist und τ eine Systemzeitkonstante ist. In einem Beispiel ist τ eine Funktion des Luftstroms durch den Zylinder, dessen Temperatur geschätzt wird, und der Motortemperatur. Insbesondere strömt Luft durch den Zylinder, wenn der Kraftstofffluss durch den Zylinder abgeschaltet ist und die Verbrennung im Zylinder beendet wird. Der Wert von τ erhöht sich, wenn der Luftstrom durch den Zylinder abnimmt, und der Wert von τ nimmt ab, wenn der Luftstrom durch den Zylinder zunimmt. Der Wert von τ nimmt ab, wenn sich die Motortemperatur erhöht, und der Wert von τ nimmt zu, wenn die Motortemperatur sinkt. Der Wert von CYL_tmp nähert sich dem Wert CYLss, wenn der Zylinder für eine längere Zeit nicht abgeschaltet wird. Das Verfahren 3500 geht zu 3506 über.At 3502, the method estimates 3500 engine cylinder temperatures via a model and/or counts an actual total number of engine cycles over which the deactivated cylinders are deactivated. The temperatures of the activated and deactivated cylinders are modeled. In one example, a steady-state cylinder temperature is determined at 3504 via the following equation: $$\begin{array}{l}CYLss=Cyl\_temp\_fn\left(N,L,Cyl\_d\_state\right)\cdot AF\_fn\left(afr\right)\cdot Spk\_fn\left(spkMBT\right)\\ \cdot EGR\_fn\left(EGR\right)\end{array}$$

where CYLss is the estimate of a steady-state cylinder temperature (e.g., temperature of a cylinder); Cyl_temp_fn is the cylinder temperature as a function of engine speed (N), engine load (L), and cylinder deactivation state (CYL_d_state); AF_fn is a function that provides a real-number multiplier for the in-cylinder air-fuel ratio (afr); Spk_fn is a function that provides a real-number multiplier for cylinder firing based on spark retard for MBT ignition timing (spkMBT); and EGR_fn is a function that provides a real-number multiplier for the percentage of exhaust gas recirculation (EGR). CYL_d_state determines whether the cylinder is on and burning air and fuel or not, so the CYLss output changes as the engine cylinder changes from on to off or vice versa. The steady-state temperature of a cylinder is varied by a time constant to provide the estimate of the cylinder temperature via the following equation: $$CY{L}_{tmp}=CY{L}_0{e}^{\frac{-t}{\tau }}+CYLss\left(1-e^{\frac{-t}{\tau }}\right)$$

where CYL _tmp is the final estimated cylinder temperature, CYL ₀ is the initial cylinder temperature, t is time, and τ is a system time constant. In one example, τ is a function of the airflow through the cylinder whose temperature is being estimated and the engine temperature. Specifically, air flows through the cylinder when fuel flow through the cylinder is shut off and combustion in the cylinder is terminated. The value of τ increases as airflow through the cylinder decreases and the value of τ decreases as airflow through the cylinder increases. The value of τ decreases as engine temperature increases and the value of τ increases as engine temperature decreases. The value of CYL _tmp approaches the value of CYLss if the cylinder is not shut off for an extended period of time. Method 3500 proceeds to 3506.

At 3506, method 3500 counts an actual total number of engine cycles over which the one or more cylinders are deactivated and not combusting air and fuel. In one example, a counter counts the actual number of engine cycles over which the one or more cylinders are deactivated by counting an actual total number of engine revolutions since the one or more cylinders are deactivated and dividing the result by two since there are two engine revolutions in one engine cycle. The actual number of engine revolutions is determined via the output of the engine crankshaft position sensor.

There are several ways to deactivate engine cylinders. One approach is to shut off fuel supply to a cylinder while the cylinder's valves are opened and closed during a cylinder cycle. The cylinder cooling rate is high with this method of cylinder deactivation.

Another way to deactivate a cylinder is to deactivate the cylinder's intake valve in a closed state while burning air and fuel in the cylinder, stop fuel injection to the cylinder while venting combustion byproducts from the cylinder, and then deactivate the cylinder's exhaust valves in a closed state while deactivating the cylinder's intake valves in a closed state. This creates a negative pressure in the cylinder. The cylinder cooling rate for cylinders is mediocre with this method of cylinder deactivation.

Another method for deactivating a cylinder is to vent the combustion products from the cylinder, shut off the fuel supply to the cylinder, introduce fresh air into the cylinder, and then keep the cylinder's intake and exhaust valves closed for an entire engine cycle without venting any of the cylinder's contents. The cylinder cooling rate for cylinders is moderate with this method of cylinder deactivation.

Yet another way to deactivate cylinders is to close the intake valves after introducing fresh air, combusting an air-fuel mixture in the cylinder, terminating fuel injection to the cylinders, and retaining combustion byproducts in the cylinders by keeping the intake and exhaust valves closed throughout an engine cycle. The cylinder cooling rate is slow with this method of cylinder deactivation. Individual spark advance timing can be provided for each way to deactivate engine cylinders.

At 3508, method 3500 monitors knock of all engine cylinders. All engine cylinders may be checked for knock via one or more engine knock sensors. Engine knock sensors may include, but are not limited to, accelerometers, pressure sensors, and acoustic sensors. Knock for individual cylinders may be monitored during predetermined crankshaft angular intervals or windows. Engine knock may be present if the output of a knock sensor exceeds a threshold. Method 3500 proceeds to 3510.

At 3510, method 3500 reduces the possibility of knock in the engine cylinders where knock is indicated. In one example, method 3500 reduces the possibility of engine knock in cylinders where engine knock was indicated at 3508 by retarding the ignition timing of the cylinders where engine knock was indicated. In other examples, the start of fuel injection timing may be retarding. Method 3500 proceeds to 3512.

At 3512, method 3500 advances the spark timing of cylinders where spark timing has been retarded to reduce the possibility of engine knock. Spark timing is advanced to improve engine fuel efficiency, engine emissions, and engine efficiency. Spark timing may be advanced from the retarded spark timing to a spark timing limit (e.g., minimum spark advance for best engine torque (MBT)) based on a base spark advance gain.

An advance gain for a cylinder may be based on the cylinder's temperature estimated at 3504 and/or the counted number of cycles the cylinder has been deactivated and the counted number of cylinder cycles the cylinder has been activated since the cylinder was last deactivated. The base advance gain may be added to the retarded spark timing. In one example, the advance gain may be expressed as X degrees/second, where the value of variable X is based on cylinder temperature. Accordingly, ignition may be advanced from a retarded timing by adding the advance gain value to the retarded spark timing. For example, if the MBT ignition timing is 20 degrees before top dead center and the ignition timing is 10 degrees before top dead center in response to engine knock, the advance gain advances the ignition timing from 10 degrees before top dead center to 20 degrees before top dead center in one second, unless engine knock is indicated during the advance of the ignition timing. In other examples, the advance gain may be a multiplier that increases or decreases a base ignition timing. For example, the advance gain may be a real number that varies between 1 and 2, so if a base ignition timing is 10 degrees before top dead center, the ignition timing can be advanced up to 20 degrees before top dead center by multiplying the base ignition timing by the advance gain. In this way, the ignition timing can be advanced back to the MBT timing, improving engine emissions, fuel efficiency, and performance. Procedure 3500 moves to the end.

Alternatively, the spark gain may be a function of the counted number of cycles the cylinder was deactivated and the counted number of cylinder cycles the cylinder was activated since the cylinder was last deactivated. For example, if the cylinder was deactivated for 10,000 engine cycles and activated for 5 engine cycles before knock occurred in the cylinder, the spark gain may be a larger value (e.g., 2 degrees/second). However, if the cylinder was deactivated for 500 engine cycles and activated for 5 cycles before knock occurred in the cylinder, the spark gain may be a smaller value (e.g., 1 degree/second).

Accordingly, a rate at which spark advance may be made after retarding spark for engine knock may be adjusted in response to cylinder temperatures and/or the number of actual total engine cycles since one or more cylinders were deactivated. Consequently, the rate at which spark advance may be adjusted to reduce the possibility of engine knock when spark advance is made. However, spark advance may be made at a rate that improves engine efficiency, fuel economy, and power.

Accordingly, the procedure under 35 a method of operating an engine, comprising: assessing whether knock is present in a cylinder combusting air and fuel, via receiving an input to a controller; adjusting, via the controller, a rate of spark advance supplied to the cylinder in response to a way the cylinder was previously deactivated after it has been assessed that knock is present. The method comprises, where the rate is a first rate if the way the cylinder is deactivated is by ceasing the supply of fuel to the cylinder and not ceasing the supply of air to the cylinder. The method comprises, where the rate is a second rate if the way the cylinder is deactivated is by ceasing the supply of fuel and air to the cylinder. The method comprises, where the second rate is greater than the first rate if the cylinder is deactivated by ceasing the supply of fuel to the cylinder and not ceasing the supply of air to the cylinder. The method includes where the input is a knock sensor, an ion sensor, or a pressure sensor. The method further includes retarding the spark delivered to the cylinder in response to an indication of knock in the cylinder.

The procedure according to 35 further provides a method of operating an engine, comprising: advancing spark delivered to a cylinder at a first rate in response to the cylinder previously being deactivated by terminating fuel flow to the cylinder without terminating air flow to the cylinder; and advancing spark delivered to the cylinder at a second rate in response to the cylinder previously being deactivated by terminating fuel flow and air flow to the cylinder. The method further comprises retarding spark delivered to the cylinder in response to an indication of knock in the first cylinder. The method includes where the first rate is greater than the second rate. The method includes where air flow to the cylinder is terminated by holding intake valves of the cylinder closed during a cycle of the cylinder. The method further comprises re-energizing the cylinder at a first engine speed and load, wherein the cylinder is re-energized with spark advance. The method includes where the spark advance is a first value when the cylinder is shut down by terminating fuel flow without terminating airflow to the cylinder. The method includes where the spark advance is a second value less than the first value when the cylinder is shut down by terminating fuel flow and airflow to the cylinder. The method further includes adjusting the spark advance in response to an estimate of a temperature of the cylinder.

Now with reference to 36 a sequence for operating an engine according to the method of 35 The vertical lines at time points T3600-T3606 represent relevant time points in the sequence. 36 shows five representations, and the representations are temporally aligned and occur simultaneously. The sequence according to 36 represents a sequence for operating a four-cylinder engine at a constant speed and constant driver demand torque.

The first representation from above in 36 is a plot of the temperature of a cylinder (e.g., a cylinder that is not burning fuel and air) versus the time for the cylinder being plotted. The vertical axis represents the cylinder temperature, and the cylinder temperature increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 36 is a plot of cylinder ignition timing versus the time for the cylinder being represented. The vertical axis represents cylinder ignition timing, and ignition advance increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 36 is a plot of the cylinder deactivation mode versus time for the cylinder being mapped. The vertical axis represents the cylinder deactivation mode. The cylinder is not deactivated if the cylinder deactivation trace is close to the center of the vertical axis. The cylinder is shut down by stopping the supply of air and fuel to the cylinder when the trace is near the vertical axis arrow. The cylinder is shut down by stopping the supply of fuel to the cylinder while air is flowing through the cylinder when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 36 is a plot of cylinder advance gain for the cylinder shown in degrees of crankshaft rotation per second versus time. The vertical axis represents advance gain, and advance gain increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 36 is a plot of indicated engine knock versus time. The vertical axis represents the indication of engine knock, and engine knock is indicated when the trace is at a level near the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T3600, the cylinder temperature is high and the cylinder's ignition timing is further advanced. The cylinder is not deactivated as indicated by the cylinder deactivation mode, while the trace is at a medium level. The cylinder's ignition gain is at a lower level, and engine knock is not indicated.

At time T3601, the engine cylinder is deactivated by terminating fuel and airflow to the cylinder, as indicated by the cylinder deactivation mode trace. Airflow to the deactivated cylinder is stopped by holding the cylinder's intake and exhaust poppet valves closed throughout an engine cycle. Alternatively, the deactivated cylinder's intake valves may be held closed while the deactivated cylinder's exhaust valves open and close throughout an engine cycle. The cylinder's temperature begins to decrease, but at a slower rate because air is not flowing through the deactivated cylinder. The cylinder's spark advance gain remains unchanged while the cylinder is deactivated. Spark timing for the cylinder is not shown because the cylinder is deactivated. No engine knock is indicated.

At time T3602, the cylinder is reactivated by supplying fuel and air to the cylinder, as indicated by the cylinder deactivation mode trace, which transitions to the mid-stage. The cylinder's spark advance gain increases based on the cylinder's temperature. The cylinder's spark timing returns to an advanced stage, and the cylinder's temperature begins to rise. No knock is indicated.

At time T3606, engine knock is indicated, and the cylinder's ignition timing is retarded to reduce engine knock. The cylinder temperature is rising, but at a level below a long-term stable level for the current engine speed and load. The cylinder is on, and the cylinder's spark advance gain is at an increased level.

Between time T3603 and time T3604, the cylinder's ignition timing is increased using spark advance gain based on the cylinder's temperature. No knock is present in the cylinder when the cylinder's spark advance increases. Spark advance increases at a predetermined rate (e.g., 10 degrees crankshaft rotation/second), so engine efficiency, power, and emissions can be improved after the cylinder's ignition timing is retarded in response to engine knock. The cylinder's spark advance gain is decreased after the cylinder is deactivated and the cylinder temperature has increased.

At time T3604, the engine cylinder is deactivated a second time by terminating fuel flow to the cylinder while air continues to flow through the deactivated cylinder, as indicated by the cylinder deactivation mode trace. The cylinder temperature is at a level it was at time T3600 and then begins to decrease more rapidly as the air flowing through the cylinder cools the cylinder. No knock is indicated in the cylinder because the cylinder is deactivated.

At time T3605, the cylinder is re-energized by supplying spark and fuel to the cylinder. The cylinder may be re-energized in response to an increase in demand torque or another condition. The cylinder's ignition timing is at a more advanced value or time. The cylinder temperature begins to increase after the cylinder is re-energized. The cylinder's advance gain is also increased in response to the cylinder being energized. No knock is indicated in the cylinder.

At time T3606, engine knock is indicated. The cylinder temperature is at a lower level and when knock is indicated, the ignition timing for the cylinder is retarded in response to knock in the cylinder. The cylinder temperature continues to rise.

After time T3606, the cylinder's ignition timing is advanced at a predetermined rate (e.g., 15 degrees crankshaft rotation/second9) so that engine efficiency, power, and emissions can be improved after the cylinder's ignition timing is retarded in response to engine knock. The cylinder's ignition timing ramps up, and it increases at a faster rate than at time T3606. The ignition timing can be advanced at a faster rate because the cylinder temperature is lower than at time T3606. Engine knock in the cylinder is not indicated, and the cylinder temperature continues to rise.

In this way, the engine's ignition timing can be adjusted in response to the cylinder deactivation mode and cylinder advance gain. Furthermore, engine knock can be reduced by reducing the reduction in engine power and emissions.

Now, with reference to 37 a method for controlling engine knock in the presence of cylinder deactivation is shown. The method according to 37 can be integrated into the system that is 1A-6C The procedure according to 37 may be contained as executable instructions stored in non-volatile memory. The method according to 37 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

Referring now to 3702, method 3700 determines engine knock windows for detecting knock in each engine cylinder. In one example, the engine knock detection windows are engine crankshaft intervals at which engine knock is expected to occur. For example, if the compression stroke at top dead center for cylinder number one is 0 degrees of crankshaft rotation, knock in cylinder number one may be expected to occur in a range of between 20 degrees of crankshaft rotation after the compression stroke of cylinder number one at top dead center and 50 degrees of crankshaft rotation after the compression stroke of cylinder number two at top dead center. Thus, knock detection for cylinder number one in this example is between 20 and 50 degrees of crankshaft rotation after the compression stroke of cylinder number one at top dead center. The knock detection windows for other engine cylinders may be defined similarly. The engine knock window ranges for each cylinder can be determined empirically and stored in a table or function in the controller's memory. The table can be maintained via engine speed and engine torque. Method 3700 proceeds to 3704.

At 3704, method 3700 selectively samples one or more engine knock sensor outputs based on the present engine position and the engine knock window. For example, method 3700 samples an engine knock sensor in a range of between 20 degrees of crankshaft rotation after the compression stroke of cylinder number one at top dead center and 50 degrees of crankshaft rotation after the compression stroke of cylinder number one at top dead center to determine the knock sensor output for the knock window of cylinder number one. Method 3700 proceeds to 3706.

At 3706, method 3700 determines whether a good signal-to-noise ratio exists for the knock sensor output in the most recent or present knock sensor window. In one example, method 3700 may be based on assessing the predetermined signal-to-noise ratios stored in a table or function in the controller's memory. The table or function may be populated according to the present cylinder knock window, the present engine speed, and the present engine torque. If method 3700 judges that a good signal-to-noise ratio exists, the answer is yes and method 3700 proceeds to 3720. Otherwise, the answer is no and method 3700 proceeds to 3708.

At 3708, method 3700 judges whether one or more engine cylinders are deactivated. In one example, variables in memory contain values that identify deactivated cylinders. For example, a variable representing the operating state of cylinder number one may have a value of zero when the cylinder is deactivated and a value of one when the cylinder is activated and combusting fuel and air. If method 3700 judges that one or more engine cylinders are deactivated, the answer is yes and method 3700 proceeds to 3710. Otherwise, the answer is no and method 3700 proceeds to 3740.

At 3710, method 3700 assesses whether the knock sensor output noise in the knock window at the present crankshaft angle (e.g., present knock window) or whether the knock sensor output noise in a knock window where the knock sensor output was only sampled (e.g., present knock window) was affected by the fuel- and air-based cylinder deactivation of a cylinder. For example, the combustion events for eight-cylinder engines are only 90 degrees of crankshaft rotation away. Therefore, for an eight-cylinder engine with a firing order of 1-3-7-2-6-5-4-8, the combustion noise (e.g., valve closing and block vibration induced by combustion pressure) from cylinder number 6 would enter the knock window of cylinder number 5. If method 3700 evaluates a knock sensor noise in the knock sensor of cylinder number five, and cylinder number five is deactivated by shutting off fuel flow and airflow to cylinder number five, method 3700 may judge that the fuel- and air-based cylinder deactivation impacts the knock sensor noise in the knock window of cylinder number five. Note that even though cylinder number five is deactivated in this example, the noise in its knock window may be used to process the knock sensor output when cylinder number five is activated during low signal-to-noise ratio conditions.

Alternatively, if method 3700 evaluates knock sensor noise in the knock sensor of cylinder number five, cylinder number six is deactivated by shutting off fuel flow and air flow to cylinder number six, and the noise (e.g., noise from exhaust valves closing while intake valves are held closed during a cylinder cycle, or noise from compression and expansion in the deactivated cylinder) from cylinder number six enters the knock window of cylinder number five while cylinder number five is on and combusting fuel and air, method 3700 may assess that fuel and air-based cylinder deactivation is impacting the knock sensor noise in the knock window of cylinder number five. If method 3700 judges that the knock sensor output noise in the knock window at the present crankshaft angle (e.g., present knock window) or if the knock sensor output noise in a knock window in which the knock sensor output was only sampled (e.g., present knock window) was affected by the fuel and air-based cylinder deactivation of a cylinder, the answer is yes and method 3700 proceeds to 3742. Otherwise, the answer is no and method 3700 proceeds to 3712.

At 3712, method 3700 assesses whether the knock sensor output noise in the knock window at the present crankshaft angle (e.g., present knock window) or whether the knock sensor output noise in a knock window in which the knock sensor output was only sampled (e.g., present knock window) was affected by fuel-based cylinder deactivation of a cylinder. For example, if method 3700 evaluates knock sensor noise in the knock window of cylinder number five, and cylinder number five is deactivated by shutting off fuel flow while air flows to cylinder number five, method 3700 may assess that fuel-based cylinder deactivation affects the knock sensor noise (e.g., valve opening and closing noise of cylinders numbers five and six, and compression and expansion noise of cylinders numbers five and six) in the knock window of cylinder number five.

Alternatively, if method 3700 evaluates a knock sensor noise in the knock sensor of cylinder number five, cylinder number six is deactivated by shutting off fuel flow to cylinder number six while air is flowing to cylinder number six, and the noise (e.g., noise from exhaust valves closing while intake valves are held closed during a cylinder cycle, or noise from compression and expansion in the deactivated cylinder) from cylinder number six enters the knock window of cylinder number five while cylinder number five is on and combusting fuel and air, method 3700 may judge that fuel and air-based cylinder deactivation is affecting the knock sensor noise in the knock window of cylinder number five. If method 3700 judges that the knock sensor output noise in the knock window at the present crankshaft angle (e.g., present knock window) or whether the knock sensor output If the knock sensor output was only sampled during a knock window (e.g., present knock window) and the knock sensor output was affected by fuel-based cylinder deactivation of a cylinder, the answer is yes and method 3700 proceeds to 3742. Otherwise, the answer is no and method 3700 proceeds to 3730.

At 3714, method 3700 bandpass filters the output from a knock sensor sensed during the knock window. The bandpass filter may be a first-order or higher-order filter. An average of the filtered knock sensor data is taken to provide a second knock reference value. In some examples, the second knock reference value may be determined under conditions where knocking is not expected to occur. For example, a second knock reference value may be determined when spark timing is retarded three degrees of crankshaft rotation before boundary spark timing. Further, second knock reference values may be determined periodically (e.g., once for every 1,000 combustion events in a cylinder at a particular engine speed and torque) instead of every engine cycle. Method 3700 proceeds to 3716.

At 3716, method 3700 processes the knock sensor data sampled in the current knock window based on the second knock reference to determine whether knock is present in the cylinder in which combustion occurred for the current knock window. In one example, the knock sensor data sampled in the current knock window is integrated to provide an integrated knock value. The integrated knock value is then divided by the second knock reference value, and the result is compared to a threshold. If the result is greater than the threshold, knock is indicated for the cylinder associated with the knock region. Otherwise, no knock is indicated. Knock may be indicated by changing a value of a variable in memory. Method 3700 proceeds to 3718.

At 3718, method 3700 adjusts an actuator to reduce engine knock. In one example, spark timing for the cylinder associated with the knock window is retarded. Additionally, or alternatively, airflow to the cylinder associated with the knock window may be reduced by adjusting valve timing. In another example, an air-fuel ratio of the cylinder associated with the knock window may be enriched by adjusting the timing of a fuel injection system. Method 3700 exits after actions are taken to reduce engine knock.

At 3720, method 3700 judges whether one or more engine cylinders are re-enabled. Method 3700 may judge that one or more engine cylinders are being re-enabled or that their re-enablement is requested based on one or more variables in the memory change state. For example, a variable representing the operating state of cylinder number one may have a value of zero when the cylinder is deactivated, and the value may transition to a value of one when the cylinder is re-enabled. If method 3700 judges that one or more engine cylinders should be re-enabled, the answer is yes and method 3700 proceeds to 3722. Otherwise, the answer is no and method 3700 proceeds to 3724.

At 3722, method 3700 sets one or more knock reference values for the cylinders to be reactivated to a predetermined value or values that the knock reference values had just before the cylinders to be reactivated were deactivated. The previously determined value may be empirically determined and stored in memory. The values that the knock reference values had just before the cylinders to be reactivated were deactivated are stored in memory when cylinder deactivation is requested. Thus, the knock reference values for knock windows of each cylinder at various engine speeds and torques are stored in memory in response to cylinder deactivation, and the same knock reference values are retrieved from memory in response to activating deactivated cylinders so that the knock reference values are appropriate for activated cylinder states, rather than using knock reference values determined during cylinder deactivation. Retrieving the knock reference values from memory may improve knock detection when cylinders are reactivated. Procedure 3700 goes to 3724.

At 3724, method 3700 bandpass filters the output from a knock sensor sensed during the knock window. The bandpass filter may be a first-order or higher-order filter. The filtered knock sensor data is averaged to provide a third knock reference value. In some examples, the third knock reference value may be determined under conditions under which knock is not expected to occur. For example, a third knock reference value may be determined when spark timing is retarded three degrees of crankshaft rotation before boundary spark timing. Further, third knock reference values may be determined periodically (e.g., once for every 1000 combustion events in a cylinder at a particular engine speed and torque) instead of every engine cycle. The knock reference value may not be corrected to a third reference value until a predetermined amount of time or engine cycles have occurred since cylinder reactivation. Instead, the third knock reference value may be the knock reference value determined at 3722 until the predetermined conditions have been met. Method 3700 proceeds to 3726.

At 3726, method 3700 processes the knock sensor data sampled in the current knock window based on the third knock reference to determine whether knock is present in the cylinder in which combustion occurred for the current knock window. In one example, the knock sensor data sampled in the current knock window is integrated to provide an integrated knock value. The integrated knock value is then divided by the third knock reference value, and the result is compared to a threshold. If the result is greater than the threshold, knock is indicated for the cylinder associated with the knock region. Otherwise, no knock is indicated. Knock may be indicated by changing a value of a variable in memory. Method 3700 proceeds to 3718.

At 3730 and 3740, method 3700 bandpass filters the output from a knock sensor sensed during the knock window. The bandpass filter may be a first-order or higher-order filter. An average of the filtered knock sensor data is taken to provide a fourth knock reference value. In some examples, the fourth knock reference value may be determined under conditions where knocking is not expected to occur. For example, a fourth knock reference value may be determined when spark timing is retarded three degrees of crankshaft rotation before boundary spark timing. Further, fourth knock reference values may be determined periodically (e.g., once for every 1,000 combustion events in a cylinder at a particular engine speed and torque) instead of every engine cycle. Method 3700 proceeds to 3746.

At 3746, method 3700 judges whether the fourth knock value is greater than a threshold. The threshold may be determined empirically and stored in memory. If the further knock reference value exceeds the threshold, the knock intensity value may be reduced due to how the intensity is determined. To improve the signal-to-noise ratio of the knock sensor output, the first knock reference value (e.g., determined at 3742) or the second knock reference value (e.g., determined at 3714) may be selected to process knock sensor data instead of the fourth knock reference value. If method 3700 judges that the fourth knock reference value is greater than the threshold, the answer is yes and method 3700 proceeds to 3750. Otherwise, the answer is no and method 3700 proceeds to 3748.

At 3748, method 3700 processes the knock sensor data sampled in the current knock window based on the fourth knock reference to determine whether knock is present in the cylinder in which combustion occurred for the current knock window. In one example, the knock sensor data sampled in the current knock window is integrated to provide an integrated knock value. The integrated knock value is then divided by the fourth knock reference value, and the result is compared to a threshold. If the result is greater than the threshold, knock is indicated for the cylinder associated with the knock region. Otherwise, no knock is indicated. Knock may be indicated by changing a value of a variable in memory. Method 3700 proceeds to 3718.

At 3750, method 3700 processes the knock sensor data sampled in the present knock window based on the first or second knock reference determined for the present engine speed and torque, but without deactivated cylinders, to determine whether combustion is present in the cylinder in which combustion occurred for the present knock window. The integrated knock value is then divided by the first or second knock reference value, and the result is compared to a threshold. If the result is greater than the threshold, knock is indicated for the cylinder associated with the knock region. Otherwise, no knock is indicated. Knock may be indicated by changing a value of a variable in memory. The first knock reference value may be used to determine engine knock during a first condition, and the The second knock reference may be used to determine engine knock during a second condition. For example, the first knock reference value may be used when the engine valve closing noise exceeds a threshold. The second knock reference value may be used when the engine valve closing noise falls below a threshold. Method 3700 proceeds to 3718.

At 3742, method 3700 bandpass filters the output from a knock sensor sensed during the knock window. The bandpass filter may be a first-order or higher-order filter. An average of the filtered knock sensor data is taken to provide a first knock reference value. In some examples, the first knock reference value may be determined under conditions where knocking is not expected to occur. For example, a first knock reference value may be determined when spark timing is retarded three degrees of crankshaft rotation before boundary spark timing. Further, first knock reference values may be determined periodically (e.g., once for every 1,000 combustion events in a cylinder at a particular engine speed and torque) instead of every engine cycle. Method 3700 proceeds to 3744.

At 3744, method 3700 processes the knock sensor data sampled in the current knock window based on the first knock reference to determine whether knock is present in the cylinder in which combustion occurred for the current knock window. In one example, the knock sensor data sampled in the current knock window is integrated to provide an integrated knock value. The integrated knock value is then divided by the first knock reference value, and the result is compared to a threshold. If the result is greater than the threshold, knock is indicated for the cylinder associated with the knock region. Otherwise, no knock is indicated. Knock may be indicated by changing a value of a variable in memory. Method 3700 proceeds to 3718.

Method 3700 may be performed for each engine cylinder as the engine rotates, through all engine cylinder knock windows in an engine cycle. The examples in the description of method 3700 are exemplary in nature and are not intended to limit the disclosure.

Additionally, knock control may be interrupted for deactivated cylinders by not updating variables and/or adjusting spark timing to deactivated cylinders (e.g., not providing spark to deactivated cylinders). In one example, deactivated cylinders are indicated to an engine knock control so that the knock control does not need to further process knock sensor data for deactivated cylinders.

In this way, knock reference values can be adjusted in response to cylinder deactivation modes and cylinder deactivation to improve signal-to-noise ratios and engine knock detection. Furthermore, multiple knock reference values can be provided at a given engine speed and torque based on cylinder deactivation.

Now with reference to 38 a sequence for operating an engine according to the method of 37 The vertical lines at time points T3800-T3804 represent relevant time points in the sequence. 38 shows three representations, and the representations are temporally aligned and occur simultaneously. The sequence according to 38 represents a sequence for operating a four-cylinder engine at a constant speed and constant driver demand torque.

The first representation from above in 38 is a plot of a knock reference value for cylinder number one versus time. The vertical axis represents the knock reference value for cylinder number one, and the knock reference value increases in the direction of the vertical axis arrow. A higher knock reference value indicates louder background engine noise (e.g., engine noise is not caused by knock in the cylinder being evaluated for knock). The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The knock reference value for cylinder number one may be based on a first, second, third, or further reference value depending on operating conditions. The horizontal line 3802 represents a threshold above which the fourth knock reference value cannot be selected.

The second illustration from the top in 38 is a plot of a selected knock reference value for cylinder number one versus time. The vertical axis represents the selected Knock reference value for cylinder number one, and the knock reference value increases in the direction of the vertical axis arrow. The selected knock reference value can be based on a first, second, third, or fourth knock reference value. The fourth knock reference values are calculated as shown in 37 described and the selected knock reference is based on the existing vehicle conditions. The selected reference value is the reference value used to process the knock sensor information retrieved from the knock sensor to assess whether knock is indicated or not (e.g., at 3748 after 37 ). The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 38 is a plot of cylinder deactivation mode versus time. The vertical axis represents cylinder deactivation mode. Cylinders are not deactivated when the cylinder deactivation trace is near the midpoint of the vertical axis. Deactivated cylinders are deactivated by stopping the supply of air and fuel to the deactivated cylinders when the trace is near the vertical axis arrow. Deactivated cylinders are deactivated by stopping the supply of fuel to the deactivated cylinders while air flows through the deactivated cylinders when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time 3800, the knock reference value of cylinder number one is a higher average value below the threshold 3802. The knock reference value for cylinder number one is the third knock reference value (e.g., 3724 from 37 ) because the cylinders are not deactivated and the knock sensor signal-to-noise ratio is low. Engine cylinders are not deactivated, as indicated by the deactivated cylinder state at mid-level. The selected knock reference mode is the value of the knock reference value for cylinder number one, because the knock reference value for cylinder number one is less than threshold 3802.

At time 3801, the knock reference value of cylinder number one changes to a lower value below the threshold 3802. The knock reference value of cylinder number one is the first knock reference value (e.g., 3742 from 37 ), because the cylinders are deactivated via fuel and air, and because the signal-to-noise ratio of the knock sensor is low. Engine cylinders are deactivated via air and fuel (e.g., fuel flow and airflow through cylinder number one is terminated), as indicated by the deactivated cylinder state at the low level. The selected knock reference mode is the value of the knock reference value for cylinder number one, because the knock reference value for cylinder number one is less than threshold 3802. Because the cylinders are deactivated at time T3801, and because the deactivated cylinder affects the noise in the knock window of cylinder number one, the reference value of cylinder number one is the first knock reference value (e.g., from 3742 37 ).

At time T3802, the knock reference value for cylinder number one increases in response to cylinder reactivation. The knock reference value for cylinder number one is the third knock reference value (e.g., 3724 from 37 ), as this was the value before the cylinders were deactivated at time T3801. The engine cylinders are reactivated by supplying air and fuel to cylinder number one, as indicated by the deactivated cylinder state at mid-level. The selected knock reference value is set to the knock reference value of cylinder number one before the cylinders were deactivated at time T3801. By using the knock reference value before the cylinders were deactivated, an improved knock reference value can be provided because the knock reference value is based on activated cylinders (e.g., the current engine operating state) and not deactivated cylinders (e.g., previous engine operating state).

At time 3803, the knock reference value of cylinder number one changes to a lower value below the threshold 3802. The knock reference value of cylinder number one is the second knock reference value (e.g., 3714 from 37 ), because the cylinders are deactivated via fuel (e.g., fuel injection to the cylinders is stopped while air flows through the cylinders) and because the signal-to-noise ratio of the knock sensor is low. The selected knock reference value is the value of the knock reference value for cylinder number one, because the knock reference value for cylinder number one is less than threshold 3802. Because the cylinders are deactivated at time T3803 and because the deactivated cylinder affects the noise in the knock window of cylinder number one, the reference value of cylinder number one is the second knock reference value (e.g., from 3714 37 ).

At time T3804, the knock reference value for cylinder number one increases in response to cylinder reactivation. The knock reference value for cylinder number one is the third knock reference value (e.g., 3724 from 37 ), as this was the value before the cylinders were deactivated at time T3803. The engine cylinders are reactivated by supplying air and fuel to cylinder number one, as indicated by the deactivated cylinder state at mid-level. The selected knock reference value is set to the knock reference value of cylinder number one before the cylinders were deactivated at time T3803.

In this way, the cylinder knock reference values, which are the basis for determining the presence or absence of engine knock, can be adjusted in response to cylinder deactivation and cylinder deactivation mode.

Now, with reference to 39 A method for performing the diagnosis of an engine is shown. The method according to 39 can be integrated into the system that is 1A-6C The procedure according to 39 may be contained as executable instructions stored in non-volatile memory. The method according to 39 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 3902, method 3900 monitors the operating states of engine intake and exhaust valves. In one example, the operating states of engine intake and exhaust valves are monitored by pressure sensors in the engine cylinders, the engine exhaust system, and/or the engine intake system (e.g., in the engine intake manifold). Method 3900 proceeds to 3904.

At 3904, method 3900 assesses whether cylinder deactivation (e.g., stopping combustion in the cylinder or cylinders) is requested or whether cylinder deactivation is currently in progress. Method 3900 may determine which engine cylinders are on (e.g., combusting air and fuel) and off, as at 1118 in 11 described, or activated cylinders may be values of variables determined at specific locations in memory. The values of the variables may be revised each time a cylinder is activated or deactivated. For example, a variable in memory may indicate the operating status of cylinder number one. A value of one in the variable may indicate that cylinder number one is activated, while a value of zero in the variable may indicate that cylinder number one is deactivated. In this way, the operating status of each engine cylinder may be determined. A request to deactivate cylinders may also be based on a value of a variable in memory. Cylinder activation and deactivation requests may be commands issued by the controller. If method 3900 judges that one or more cylinders are deactivated or that deactivation is requested, the answer is yes and method 3900 proceeds to 3906. Otherwise, the answer is no and method 3900 proceeds to 3930.

At 3906, method 3900 judges whether one or more poppet valves of cylinders requested to be deactivated are energized after commanding the poppet valve to deactivate and after providing sufficient time to deactivate the cylinders (e.g., a full engine cycle has been performed after a request). Based on cylinder pressure, exhaust pressure, or intake pressure, it may be determined that one or more poppet valves remain energized. Alternatively, sensors may be positioned on the individual valve actuators to determine whether valves continue to operate after being commanded to deactivate them. If method 3900 judges that one or more poppet valves commanded to deactivate (e.g., held closed during an engine cycle as the engine rotates) continue to operate (e.g., opening and closing during the engine cycle as the engine rotates), the answer is yes, and method 3900 proceeds to 3908. Otherwise, the answer is no and method 3900 proceeds to 3920. Note that method 3900 may wait a certain amount of time after the command to turn off the one or more poppet valves is issued before proceeding to 3908 to ensure that the state of the poppet valve is valid.

At 3908, method 3900 reactivates the cylinder or cylinders in which the poppet valves continue to operate. The cylinder or cylinders are reactivated by activating the cylinder's poppet valves and supplying fuel and spark to the cylinders. By activating the cylinder poppet valves, air is provided to the cylinder. Air and fuel are combusted in the activated cylinders. Method 3900 proceeds to 3910.

At 3910, method 3900 removes the cylinders with one or more valves that have not deactivated from a list of cylinders that can be deactivated. Thus, method 3900 inhibits cylinder deactivation for the cylinders with valves that have not deactivated when the valves were requested to deactivate. Method 3900 proceeds to 3912.

At 3912, method 3900 deactivates an alternate cylinder to provide a desired number of deactivated cylinders. For example, if cylinder number two of a four-cylinder engine is requested to deactivate, but the valves of cylinder number two do not deactivate while cylinders number one, three, and four are activated, cylinder number two is reactivated as described at 3910 and a command is issued to deactivate cylinder number three. In this example, the desired number of deactivated cylinders is one and the desired number of activated cylinders is three. In this manner, the desired number of activated and deactivated cylinders may be provided. Consequently, improved fuel efficiency may be maintained even in the presence of valve train wear. Method 3900 proceeds to exit.

At 3920, method 3900 provides a desired amount of engine torque via activated cylinders. The desired amount of engine speed may be based on a driver demand torque, and the driver demand torque may be based on an accelerator pedal position and a vehicle speed. The desired amount of torque from the activated cylinders is provided by controlling airflow and fuel flow to the activated cylinders. Method 3900 proceeds to exit.

At 3930, method 3900 judges whether one or more poppet valves of cylinders requested to be energized or de-energized are de-energized after commanding the poppet valve to energize and after providing sufficient time to energize the cylinders (e.g., a full engine cycle has been completed after a request). Based on cylinder pressure, exhaust pressure, or intake pressure, it may be determined that one or more poppet valves remain de-energized. Alternatively, sensors may be positioned on the individual valve actuators to determine if valves do not open and close during an engine cycle after being commanded to energize them. If method 3900 judges that one or more poppet valves commanded to energize (e.g., open and close during an engine cycle as the engine rotates) do not open and close during the engine cycle, the answer is yes, and method 3900 proceeds to 3932. Otherwise, the answer is no and method 3900 proceeds to 3940. Note that method 3900 may wait a predetermined period of time before proceeding to 3932 after the command to turn on the one or more poppet valves is issued to ensure that the state of the poppet valve is valid.

At 3932, method 3900 deactivates the cylinder or cylinders in which the poppet valves do not open and close during a cylinder cycle. The cylinder or cylinders are deactivated by deactivating the cylinder's poppet valves and stopping fuel and spark supply to the cylinder. By deactivating the cylinder poppet valves, airflow to the cylinder ceases. Method 3900 proceeds to 3934.

At 3934, method 3900 removes the cylinders with one or more valves that have not turned on from a list of cylinders that can be turned on. Thus, method 3900 inhibits cylinder activation for the cylinders with valves that did not turn on when the valves were requested to turn on. Combustion is inhibited in cylinders that have been removed from the list of cylinders that can be turned on. Method 3900 proceeds to 3936.

At 3936, method 3900 provides requested engine torque up to the capacity of the cylinders in the list of cylinders that can be activated.

The actual total number of cylinders activated may be increased in response to the engine torque request or decreased in response to the engine torque request. As a result, a significant amount of engine torque may be provided even if poppet valves of one or more cylinders are wearing out. Method 3900 proceeds to exit.

At 3940, method 3900 provides a desired amount of engine torque via activated cylinders. The desired amount of engine speed may be based on a driver demand torque and the driver demand torque may be based on an accelerator pedal position and vehicle speed. The desired amount of torque from the activated cylinders is provided by controlling airflow and fuel flow to the activated cylinders. Method 3900 proceeds to exit.

Now with reference to 40 a sequence for operating an engine according to the method of 39 The vertical lines at time points T4000-T4005 represent relevant time points in the sequence. 40 shows five representations, and the representations are aligned in time and occur simultaneously. SS along the timeline of each representation indicates a break in the sequence. The time between the break can be long or short. The sequence after 40 represents a sequence for operating a four-cylinder engine with a firing order of 1-3-4-2.

The first representation from above in 40 is a plot of cylinder deactivation request (e.g., a request to end combustion in one or more cylinders) versus time. The vertical axis represents cylinder deactivation request, and cylinder deactivation is requested when the trace is at a level near the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The second illustration from the top in 40 is a plot of the valve operating state of cylinder number two versus time. The cylinder valves in cylinder number two are turned on when the trace is at a higher level near the vertical axis arrow. The cylinder valves in cylinder number two are turned off when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The third representation from the top in 40 is a plot of the valve operating state of cylinder number three versus time. The cylinder valves in cylinder number three are turned on when the trace is at a higher level near the vertical axis arrow. The cylinder valves in cylinder number three are turned off when the trace is at a lower level near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fourth representation from the top in 40 is a plot of the actual total number of requested engine cylinders activated versus time. The vertical axis represents the actual total number of requested cylinders activated, and the actual total number of requested cylinders activated is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

The fifth representation from the top in 40 is a plot of requested engine torque versus time. The vertical axis represents requested torque, and the requested torque value increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

At time T4000, there is no request to deactivate the cylinders, as indicated by the lower-level cylinder deactivation request. The valves of cylinders two and three are energized. The valves of cylinders two and three are energized based on the number of requested energized (e.g., burning air and fuel) cylinders being four. The requested engine torque is at a higher level.

At time 4001, the requested engine torque decreases. The requested engine torque may decrease in response to a reduction in the driver demand torque. The number of requested engine cylinders is decreased from four to three in response to the requested engine torque decreasing. Further, the cylinder deactivation request is asserted in response to the requested engine torque decreasing. Deactivation is requested for cylinder number two, and the cylinder poppet valves of cylinder number two are commanded to close. However, the valves of cylinder number two remain energized, as indicated by the valve state of cylinder number two. Since the poppet valves of cylinder number two remain energized (e.g., opening and closing during an engine cycle as the engine rotates), the command is issued to re-energize cylinder number two, as indicated by the number of requested energized cylinders, which returns to four. is displayed. Shortly thereafter, the command is given to deactivate cylinder number three in response to the number of active cylinders being changed back to three. The poppet valves of cylinder number three become inactive (e.g., are held closed throughout the engine cycle), and the requested number of active cylinders remains constant at a value of three.

At time T4002, the requested engine torque increases, and the number of requested cylinders on is increased back to four. Cylinder number three is reactivated, and the valves of cylinder number three are activated, as indicated by the valve state of cylinder number three. Cylinder number two remains on, and the cylinder deactivation request is not asserted in response to the number of requested cylinders on.

At time T4003, the cylinder deactivation request is asserted in response to the number of requested cylinders being active, which is two. The valves of cylinder number two and cylinder number three are deactivated. The requested engine torque is at a low level, allowing the engine to provide the requested torque below the full complement of active cylinders.

At time 4004, the engine torque request increases in response to an increase in driver demand torque (not shown). The number of requested active cylinders increases to a value of four in response to the increased requested torque. The valves of cylinder number three turn back on, but the valves of cylinder number two do not turn on in response to the number of requested active cylinders. Shortly after time T4004, the number of requested active cylinders transitions to a value of three, and cylinder number two is commanded to deactivate (e.g., stop supplying fuel and keep the poppet valves closed for one engine cycle). Further, the cylinder deactivation request is reasserted for cylinder number two. The engine provides as much of the requested torque as the torque capacity of the three active cylinders allows.

At time 4005, the requested engine torque is decreased in response to a decrease in driver demand torque. The number of requested active cylinders is decreased from three to two in response to the decrease in requested engine torque. The valves of cylinder number three are deactivated, and cylinders number two and three are deactivated in response to the number of requested active cylinders. The cylinder deactivation request also remains asserted.

In this way, the number of requested engine cylinders to be turned on can be adjusted in response to the valves that cannot be turned off when their deactivation is requested. Furthermore, the number of requested engine cylinders to be turned on can be adjusted in response to the valves that can be turned off when their activation is requested.

Now with reference to 41 A method for querying oxygen sensors of an engine with cylinder deactivation is shown. The method according to 41 can be integrated into the system that is 1A-6C The procedure according to 41 may be contained as executable instructions stored in non-volatile memory. The method according to 41 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 4102, method 4100 judges whether one or more cylinders of the engine are deactivated. Method 4100 may evaluate a value of a variable stored in memory to determine whether one or more engine cylinders are deactivated. If method 4100 judges that one or more engine cylinders are deactivated, the answer is yes and method 4100 proceeds to 4104. Otherwise, the answer is no and method 4100 proceeds to 4120.

At 4120, method 4100 samples an oxygen sensor of a cylinder bank twice per exhaust stroke of each cylinder in the cylinder bank. Accordingly, if the engine is a four-cylinder engine with a single bank of cylinders, method 4100 samples an exhaust gas sensor eight times in two engine revolutions. The samples are then averaged to provide an air-fuel ratio estimate for the engine. Additionally, cylinder-specific air-fuel ratios may be estimated via averaging the two samples taken on an exhaust stroke of a cylinder to determine the air-fuel ratio. Method 4100 proceeds to 4108.

At 4108, method 4100 adjusts the fuel delivered to the engine cylinders based on the oxygen sensor readings. If the oxygen sensor indicates a leaner air-fuel ratio than desired, additional fuel may be injected into the engine. If the oxygen sensor indicates a richer air-fuel ratio than desired, less fuel may be injected into the engine. Method 4100 proceeds to exit.

At 4104, method 4100 determines which engine cylinders are deactivated. In one example, method 4100 evaluates values stored in memory indicating activated and deactivated cylinders. Method 4100 determines which cylinders are deactivated and proceeds to 4106.

At 4106, method 4100 samples a cylinder bank oxygen sensor twice per exhaust stroke of each cylinder in the cylinder bank, except for exhaust strokes of deactivated cylinders, which are not sampled. Alternatively, oxygen values sampled during exhaust strokes of deactivated cylinders may be discarded. The values are then averaged to determine an average engine air-fuel ratio. Method 4100 proceeds to 4108.

By not sampling oxygen sensors during exhaust strokes of deactivated cylinders, it may be possible to reduce the air-fuel ratio bias induced by engine cam position. Specifically, if a cylinder's air-fuel mixture is leaner or richer than that of other cylinders and its exhaust gases are expelled near an exhaust stroke of a deactivated cylinder, the engine's air-fuel ratio bias can be reduced by not sampling the output from the leaner or richer cylinder twice during an engine cycle.

Now with reference to 42 A method for querying cam sensors of an engine with cylinder deactivation is shown. The method according to 42 can be integrated into the system that is 1A-6C The procedure according to 42 may be contained as executable instructions stored in non-volatile memory. The method according to 42 may be performed in conjunction with the system hardware and other methods described herein to transform an operating state of an engine or its components.

At 4202, method 4200 judges whether one or more cylinders of the engine are deactivated. Method 4200 may evaluate a value of a variable stored in memory to determine whether one or more engine cylinders are deactivated. If method 4200 judges that one or more cylinders are deactivated, the answer is yes and method 4200 proceeds to 4204. Otherwise, the answer is no and method 4200 proceeds to 4220.

At 4220, method 4200 samples an intake cam sensor twice per intake stroke of each cylinder on a cylinder bank that includes an intake cam monitored by the intake cam sensor. Similarly, method 4200 samples an exhaust cam sensor twice per exhaust stroke of each cylinder on a cylinder bank that includes an exhaust cam monitored by the exhaust cam sensor. Accordingly, if the engine is a four-cylinder engine with a single intake cam, method 4200 samples a cam sensor eight times in two engine revolutions. Cam position and speed may be determined for each sampled cam sensor value. Method 4200 proceeds to 4208.

At 4208, method 4200 adjusts a cam phase actuator command to adjust the cam position based on the cam sensor values. If the cam sensor indicates that the cam position is not at the desired position and/or if the cam is moving slower or faster than desired, the cam phase command is adjusted to reduce the error between the actual cam position and the desired cam position. Method 4200 proceeds to exit.

At 4204, method 4200 determines which engine cylinders are deactivated. In one example, method 4200 evaluates values stored in memory that indicate activated and deactivated cylinders. Method 4200 determines which cylinders are deactivated and proceeds to 4206.

At 4206, method 4200 samples a cam sensor of a cylinder bank twice per intake stroke for an intake cam or twice for each exhaust stroke for an exhaust cam, except for exhaust strokes of deactivated cylinders, which are not sampled. Alternatively, cam sensor values sampled during intake or exhaust strokes of deactivated cylinders may be discarded. The values are then processed to determine cam position and speed. Additionally, cam values may be averaged to reduce cam signal noise. Method 4200 proceeds to 4208.

By not polling cam sensors during intake and exhaust strokes from deactivated cylinders, it may be possible to reduce the cam position bias induced on the engine cam position. The rate at which a cam phase actuator moves can be affected by whether a cylinder is deactivated. For this reason, it may be desirable to eliminate cam values taken when valve springs from deactivated cylinders are not supporting cam movement relative to crankshaft position.

It should be noted that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transitory memory and executed by the control system incorporating the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Accordingly, various illustrated acts, operations, and/or functions can be performed in the illustrated order, in parallel, or in some cases omitted. Likewise, the processing order is not necessarily required to achieve the features and advantages of the embodiments described herein, but is provided for ease of processing and description. One or more of the illustrated acts, operations, and/or functions can be performed repeatedly, depending on the particular strategy employed. Furthermore, at least a portion of the described actions, operations, and/or functions may graphically represent code to be programmed into a non-transitory memory of the computer-readable storage medium in the control system. The control actions may also transform the operating state of one or more sensors or actuators in the physical domain when the described actions are performed by executing the instructions in a system including the various engine hardware components in combination with one or more controllers.

This concludes the description. A reading of this description by a person skilled in the art will reveal many changes and modifications without departing from the spirit and scope of the description. For example, this description may be applied to I3, I4, I5, V6, V8, V10, and V12 engines operating on natural gas, gasoline, diesel, or alternative fuel configurations.

Claims (15)

A method of operating an engine, comprising: assessing whether knock is present in a cylinder combusting air and fuel by receiving an input to a controller; adjusting, via the controller, a rate of spark advance supplied to the cylinder after assessing that knock is present in the cylinder in response to a possibility that the cylinder was previously deactivated. Procedure according to Claim 1 , where the rate is a first rate when the means by which the cylinder is shut down is to stop the supply of fuel to the cylinder and not to stop the supply of air to the cylinder. Procedure according to Claim 2 , where the rate is a second rate when the means by which the cylinder is shut down is to stop supplying fuel to the cylinder, admit air into the cylinder, combust air and fuel in the cylinder, and keep the cylinder's intake and exhaust valves closed throughout an entire engine cycle without venting the combustion byproducts. Procedure according to Claim 3 , the second rate being greater than the first rate when the cylinder is shut down by stopping the supply of fuel to the cylinder rather than by stopping the supply of air to the cylinder. Procedure according to Claim 1 , wherein the input is a knock sensor, an ion sensor, or a pressure sensor, wherein the rate is a third rate when the means by which the cylinder is deactivated includes introducing air into the cylinder, burning air and fuel in the cylinder, ceasing fuel flow to the cylinder, venting the contents of the cylinder, then keeping the cylinder valves closed throughout an entire engine cycle, and wherein the rate is a fourth rate when the means by which the cylinder is deactivated includes ceasing fuel injection into the cylinder, introducing air into the cylinder and fuel in the cylinder, ceasing fuel flow to the cylinder, venting the contents of the cylinder, and then keeping the cylinder valves closed throughout an entire engine cycle. Procedure according to Claim 1 further comprising retarding the ignition delivered to the cylinder in response to an indication of knock in the cylinder. Procedure according to Claim 1 , further comprising: advancing the spark delivered to the cylinder at a first rate in response to the cylinder previously being deactivated by terminating fuel flow to the cylinder without terminating air flow to the cylinder; and advancing the spark delivered to the cylinder at a second rate in response to the cylinder previously being deactivated by terminating fuel flow and air flow to the cylinder. Procedure according to Claim 7 further comprising retarding the spark delivered to the cylinder in response to an indication of knock in the first cylinder. Procedure according to Claim 8 , where the first rate is larger than the second rate. A vehicle system comprising: an engine; and a controller, including non-transitory executable instructions that, when executed by the controller, cause the controller to estimate a temperature in a cylinder that is deactivated and adjust an ignition advance rate for the cylinder after the cylinder is reactivated in response to an indication of knock in the cylinder and based on the temperature in the cylinder, and adjust a mode in which the cylinder was previously deactivated. Vehicle system according to Claim 10 , where the mode in which the cylinder was previously shut down is a mode in which air does not flow through the cylinder. Vehicle system according to Claim 10 , where the mode in which the cylinder was previously shut down is a mode in which air flows through the cylinder. Vehicle system according to Claim 10 , where the temperature in the cylinder when the cylinder is shut down is based on the air flow through the cylinder. Vehicle system according to Claim 10 , further comprising additional instructions to re-enable the first cylinder in response to an actual total number of engine revolutions since the first cylinder was deactivated. Vehicle system according to Claim 10 , where the advance rate is an ignition gain.

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