JP2009215943A - Fuel injection control device for engine - Google Patents

Abstract

An object of the present invention is to appropriately correct a fuel injection amount even when acceleration / deceleration is repeated in a state where an engine coolant temperature is substantially constant, thereby suppressing undesired air-fuel ratio fluctuations as much as possible. Thus, a fuel injection control device for an engine is provided in which unnecessary torque fluctuations and exhaust emission characteristics are not deteriorated.
SOLUTION: A target fuel injection amount calculating means 102 for calculating a target fuel injection amount based on an operating state of an engine, a head temperature estimating means 103 for estimating a temperature of a cylinder head, and a port for estimating a temperature of the intake port. Fuel that contributes to combustion in the combustion cycle starting from the next intake stroke among the fuel remaining in the cylinder and in the intake port based on the cylinder head temperature and the intake port temperature at the end of the intake stroke, at the temperature estimation means 103 A next-combustion-contributing fuel amount estimation unit 104 that estimates the amount; and a fuel-injection-amount calculation unit 104 that calculates a fuel injection amount to be injected from the fuel injection valve based on the target fuel injection amount and the next combustion-contributing fuel amount. Prepare.
[Selection] Figure 3

Description

  The present invention relates to an engine fuel injection control device, for example, an engine fuel injection control device in which a fuel injection valve that injects fuel toward an intake port is disposed.

  Conventionally, many compensation methods for fuel adhering to the wall surface of the intake port, so-called fuel liquid film, have been proposed, and typical examples thereof are as follows.

  For example, Patent Document 1 below discloses means for calculating the current equilibrium intake face fuel as a function of the engine operating state parameter, means for calculating the current intake device time constant as a function of the engine operating parameter, Means for calculating the current actual intake face fuel as a first derivative function of the moving ratio of the actual intake face fuel and the previous intake face fuel, and the moving ratio of the current intake face fuel as a function of the current balanced intake face fuel. It is described that it is repeatedly calculated and combined with the desired fuel flow rate to determine the fuel requirement. The detailed description of Patent Document 1 states that “abrupt acceleration increases the rate of fuel that accumulates on the wall surface of the intake passage, and deceleration decreases the rate of fuel that accumulates. This reason is related to changing vapor pressure. "The higher the vapor pressure, the more fuel tends to accumulate on the wall of the intake passage. The vapor pressure is a partial pressure, so air is the main influence of the pressure in the intake passage." Yes. Therefore, it is described in this prior art that the amount of liquid film in the intake port increases as the amount of intake air increases. In another explanation, when the intake manifold absolute pressure closely related to the engine load is taken on the horizontal axis and the balanced intake face fuel is taken on the vertical axis, the balanced intake surface fuel shows a curve group depending on the engine speed. It is described. As an example, the intake manifold absolute pressure and the engine rotation speed are input to the current equilibrium intake surface fuel calculation and current intake device time constant parameters.

  Another conventional technique is described in Patent Document 2 below. The technique described here is the same as that of Patent Document 1. That is, the wall fuel adhesion rate and the wall fuel removal rate are determined based on engine operating state parameters including at least the intake pipe pressure, and the wall fuel increase and wall fuel decrease are determined at predetermined intervals based on these rates. The wall fuel is corrected by this, and the basic fuel injection amount is finally corrected. In the detailed description of Patent Document 2, the wall surface fuel adhesion rate and the wall surface fuel take-off rate are functions of the intake pipe pressure, the engine cooling water temperature, the engine speed, and the intake air flow rate. The intake pipe pressure increases as the pressure increases. That is, it is described that as the air flow rate increases, the air flow rate increases.

Japanese Examined Patent Publication No. 62-48053 Japanese Patent Publication No. 3-59255

  The problems of the prior art will be described with reference to the time charts of FIGS. 28 (A), (B), and (C). FIG. 28A shows the throttle opening, FIG. 28B shows the fuel injection correction amount, and FIG. 28C shows the behavior of various temperatures (cylinder head temperature, intake port temperature, engine coolant temperature). As shown in FIG. 28 (A), when the throttle fully open acceleration and the throttle fully closed deceleration are repeated under the same operating conditions, in the conventional technology, under the situation where the engine coolant temperature remains the same ( As shown in B), the fuel injection correction amount at the first acceleration and the second acceleration does not change. Further, the fuel injection correction amount at the first deceleration and the second deceleration does not change. Actually, as shown in (C), the cylinder head temperature and the port temperature (broken line) rise by repeating full opening acceleration, and therefore, decrease as the fuel adhering to the wall evaporates. For this reason, during the second acceleration, the fuel injection correction amount increases and the air-fuel ratio becomes rich. In addition, during the second deceleration, the fuel injection correction amount decreases and the air-fuel ratio becomes lean. As described above, according to the related art, when acceleration / deceleration is repeated under a situation where the engine water temperature does not change, the same correction amount is obtained each time. As a result, unnecessary torque fluctuation, deterioration of exhaust emission characteristics, and the like may occur due to air-fuel ratio fluctuation during repeated acceleration / deceleration.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to appropriately correct the fuel injection amount even when acceleration / deceleration is repeated while the engine coolant temperature is substantially constant. To provide an engine fuel injection control device capable of suppressing undesired air-fuel ratio fluctuations as much as possible and preventing unnecessary torque fluctuations and deterioration of exhaust emission characteristics. It is in.

  In order to achieve the above object, a fuel injection control device according to the present invention is provided in an engine provided with a fuel injection valve for injecting fuel toward an intake port, and is based on an operating state of the engine. Target fuel injection amount calculating means for calculating the fuel injection amount, head temperature estimating means for estimating the temperature of the cylinder head, port temperature estimating means for estimating the temperature of the intake port, the cylinder head temperature at the end of the intake stroke, and A next combustion contribution fuel amount estimating means for estimating a fuel amount contributing to combustion in a combustion cycle starting from a next intake stroke among the fuel remaining in the cylinder and the intake port based on the intake port temperature; and the target Fuel injection amount calculating means for calculating a fuel injection amount to be injected from the fuel injection valve based on the fuel injection amount and the next combustion contributing fuel amount; It is characterized in that it comprises.

  Preferably, the head temperature estimation means estimates an average effective gas temperature based on an operating state of the engine, and estimates a cylinder head temperature based on the estimated average effective gas temperature.

  Preferably, the port temperature estimation means estimates the intake port temperature based on the estimated cylinder head temperature.

  In another preferred aspect, the next combustion contributing fuel amount estimating means estimates the port portion evaporation amount contributing to combustion in the next combustion cycle, and estimates the cylinder internal evaporation amount contributing to combustion in the next combustion cycle. Means for estimating the next combustion contribution fuel amount based on the next combustion contribution port portion evaporation amount and the next combustion contribution cylinder internal evaporation amount.

  The next combustion contribution port portion evaporation amount estimation means preferably estimates the next combustion contribution port portion evaporation amount based on the fuel injection amount at the time of executing synchronous injection and the fuel evaporation amount from the fuel adhering to the port portion. To be.

  The next combustion contributing cylinder internal evaporation amount estimation means preferably calculates the cylinder internal evaporation amount based on the fuel amount flowing into the cylinder from the fuel adhering to the intake port portion and the fuel amount evaporating from the inflow fuel in the cylinder. To be estimated.

  In another preferred embodiment, the fuel injection correction amount is reduced with the passage of time when acceleration / deceleration is repeated while the engine coolant temperature is substantially constant.

  In the fuel injection control device according to the present invention, not only the engine coolant temperature but also the cylinder head temperature and the intake port temperature are estimated and used for correcting the fuel injection amount, and the cylinder head temperature and the intake port temperature are set at the end of the intake stroke. Based on the fuel remaining in the cylinder and in the intake port, the amount of fuel that contributes to combustion is estimated in the combustion cycle starting from the next intake stroke (cycle consisting of intake, compression, explosion expansion, and exhaust strokes). The fuel injection amount to be injected from the fuel injection valve is calculated based on the next combustion contribution fuel amount and the target fuel injection amount, so that acceleration / deceleration is repeated while the engine coolant temperature is substantially constant. Therefore, the fuel injection amount can be appropriately corrected in the entire operation region including when starting and during acceleration / deceleration transients. To be able to suppress the dynamic effectively, can so as not to lead to deterioration of unnecessary torque variation and exhaust emission characteristics.

  Embodiments of an engine fuel injection control apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an embodiment (first example) of an engine fuel injection control apparatus according to the present invention, together with an example of an in-vehicle engine to which the engine is applied.

  In FIG. 1, an engine 10 to which the fuel injection control device 1 of the present embodiment is applied has, for example, four cylinders # 1, # 2, # 3, and # 4 (# 1 is representatively shown in the drawing). A spark ignition type multi-cylinder gasoline engine, which is slidably inserted into each cylinder # 1, # 2, # 3, and # 4 of the cylinder 12 including a cylinder head 12A and a cylinder block 12B. The piston 15 is connected to the crankshaft 13 via a connecting rod 14. Above the piston 15, a combustion working chamber 17 (this portion is referred to as a cylinder) having a combustion chamber (ceiling or roof) having a predetermined shape is defined, and each cylinder # 1, # 2, # 3, # 4 is defined. An ignition plug 35 connected to an ignition unit including an ignition coil 34 and the like is provided in the combustion operation chamber 17.

  The air used for the combustion of fuel is from an air cleaner 51, a tubular passage portion in which an air flow sensor 53 such as a hot wire type and an electric throttle valve 25 are arranged, a collector 27, an intake manifold (manifold) 28, an intake air The combustion working chambers 17 of the cylinders # 1, # 2, # 3, and # 4 pass through the intake passage 20 including the ports 29 and the like, and are connected to the downstream end (end portion of the intake port 29). Inhaled. A fuel injection valve 30 for injecting fuel toward the intake port 29 is provided for each cylinder (# 1, # 2, # 3, # 4) in the downstream portion of the intake passage 20 (intake manifold 28). Further, an intake pressure sensor 52 for detecting an intake pipe pressure (internal pressure on the downstream side of the throttle valve 25 in the intake passage 20) is disposed in the collector 27 of the intake passage 20.

  The air-fuel mixture of the air sucked into the combustion working chamber 17 and the fuel injected from the fuel injection valve 30 is burned by spark ignition by the spark plug 35, and the combustion waste gas (exhaust gas) is discharged from the combustion working chamber 17. The exhaust gas is discharged to the outside (in the atmosphere) through an exhaust passage 41 including an exhaust port, an exhaust manifold, and an exhaust pipe provided with an exhaust purification catalyst (for example, a three-way catalyst) through an exhaust valve 41. An oxygen concentration sensor (air-fuel ratio sensor) 57 is disposed upstream of the catalyst in the exhaust passage 40. Here, as the oxygen concentration sensor 57, a sensor whose output changes linearly with respect to the oxygen concentration is used, but instead, a signal of a high level-low level is output depending on whether the stoichiometric air-fuel ratio is richer or leaner. You may use what you do.

  Further, the fuel injection valve 30 provided for each cylinder (# 1, # 2, # 3, # 4) is supplied with fuel (gasoline etc.) in a fuel tank provided with a fuel pump, a fuel pressure regulator, and the like. The fuel injection valve 30 is supplied from an engine control unit (ECU) 100, which will be described later, and the pulse width corresponding to the operating state at that time (corresponding to the valve opening time). The valve is driven to open by a valve-opening pulse signal, and an amount of fuel corresponding to the valve-opening time is injected toward the intake port 29.

  The intake passage 20 is provided with a bypass passage 61 that bypasses the throttle valve 25 in order to perform idle speed control, and an ISC valve 62 is interposed in the passage 61, and the exhaust passage 40 and the intake passage In addition, an EGR passage 63 is provided so as to connect to the passage 20, and an EGR valve 64 is interposed in the passage 63.

  On the other hand, an engine control unit (ECU) 100 incorporating a microcomputer is provided to perform various controls of the engine 10, that is, fuel injection control in the fuel injection valve 30, ignition timing control in the spark plug 35, and the like. ing.

  Basically, the control unit 100 is well known as shown in FIG. 2, and includes a CPU 90, a ROM 91, a RAM 92, an input / output port (IO) 95, an input circuit 96, a driver. (Drive circuit) 97 and the like. In the control unit 100, signals from the sensors are sent to the input / output port 95 after processing such as noise removal by the input circuit 96. The value of the input port 95 is stored in the RAM 92 and processed in the CPU 90. A control program describing the contents of the arithmetic processing is written in the ROM 91 in advance. A value representing each actuator operation amount calculated according to the control program is stored in the RAM 92 and then sent to the output port 95.

  The control unit 100 receives, as an input signal, a signal corresponding to the intake air amount detected by the air flow sensor 53, a signal corresponding to the opening of the throttle valve 25 detected by the throttle opening sensor 58, and an input to the crankshaft 13. A signal representing the rotation (engine speed) and phase (crank angle) of the crankshaft 13 obtained from the provided crank angle sensor (rotation speed sensor) 55 (from the crank angle sensor 55, for example, every rotation angle 1 degree) A pulse signal is output), a signal representing the rotation / phase of the camshaft 23 obtained from the cam angle sensor 56 attached to the intake camshaft 23 (the signal from the cam angle sensor 56 and the crank angle sensor 55). Cylinder determination is performed based on the signal of the engine), and is arranged upstream of the three-way catalyst in the exhaust passage 40. A signal corresponding to the oxygen concentration (air-fuel ratio) from the oxygen concentration sensor 57, a signal corresponding to the engine cooling water temperature detected by the water temperature sensor 54 provided in the cylinder 12, and a main switch for operating and stopping the engine 10 The signal from the ignition key switch 59, the intake pipe pressure and the intake air temperature detected by the intake pressure sensor 52 and the intake air temperature sensor (both sensors are integrated) provided in the collector 27 portion of the intake passage 20 A corresponding signal or the like is supplied.

  The control unit 100 recognizes the operating state of the engine based on the various input signals, and calculates main operation amounts of the engine such as the fuel injection amount and the ignition timing based on the operating state.

  More specifically, the control unit 100 calculates the fuel injection amount to be injected for each cylinder # 1, # 2, # 3, # 4 based on the operating state of the engine, and calculates the calculated fuel injection. A valve opening pulse signal having a pulse width corresponding to the amount is generated, and this valve opening pulse signal is amplified to an energy sufficient to open the fuel injection valve 30 by the driver 97, and each fuel injection valve driving signal is amplified. The fuel is supplied to the fuel injection valve 30 at a predetermined timing for each of the cylinders # 1, # 2, # 3, and # 4. Further, a drive signal is sent from the driver 97 to the ignition coils 34 of the respective cylinders # 1, # 2, # 3, and # 4 so that ignition is performed at the ignition timing calculated by the control unit 100.

  Next, an embodiment of the fuel injection control executed by the control unit 100 will be specifically described. In the present embodiment, basically, for each cylinder # 1, # 2, # 3, and # 4, only once in one combustion cycle (cycle consisting of intake, compression, explosion expansion, and exhaust strokes) Fuel injection (synchronous injection) is performed at a predetermined crank angle position (intake stroke), and in this case, the fuel (gasoline) is not supplied in time. Injection (asynchronous injection) is performed. That is, asynchronous injection is performed when the fuel for the target fuel injection amount cannot be provided even with the synchronous injection. However, asynchronous injection is not performed in the compression stroke.

  As shown in the functional block diagram of FIG. 3, the control unit 100 includes an engine speed calculation means 101, a target fuel injection amount calculation means 102, a cylinder head temperature / port temperature estimation means 103, a next combustion contribution fuel amount / A fuel injection amount calculation means 104, a basic ignition timing setting means 105, an acceleration / deceleration determination means 106, an ignition timing correction means 107, a target air-fuel ratio setting means 108, and an air-fuel ratio feedback control coefficient calculation means 109 are provided.

  The engine speed calculation means 101 counts the number of times the pulse signal from the crank angle sensor 55 changes per unit time (for example, the rise or fall of the pulse) (the number of arrivals) and performs a predetermined calculation process to perform the unit. Calculate the engine speed per hour.

  The target fuel injection amount calculation means 102 calculates the target fuel injection amount required by the engine from the engine speed, the intake air amount (cylinder inflow air amount) calculated by the engine speed calculation means 101, and the equivalence ratio.

  The head port temperature estimating means 103 is a combustion cycle that starts in the next intake stroke from the engine speed, engine load, cylinder inflow air amount, engine water temperature, and ignition timing described later calculated by the engine speed calculating means 101 described above. The cylinder head temperature and the intake port temperature for predicting the amount of fuel that contributes to combustion are estimated. Here, the engine load is represented by the output of the intake pressure sensor 52 converted into the intake pipe pressure by a predetermined process, or the intake air amount measured by the air flow sensor 53.

  The next combustion contribution fuel amount / fuel injection amount calculation means 104 calculates the next combustion cycle from the engine speed, engine load, cylinder inflow air amount, cylinder head temperature, port temperature, and intake valve 21 advance value. Is calculated (predicted), the difference between the target fuel injection amount and the combustion contribution fuel amount is corrected, and the fuel injection amount is calculated.

  The basic ignition timing setting means 105 sets the optimal basic ignition timing in each region of the engine by map search based on the engine speed and the engine load described above.

  The acceleration / deceleration determining means 106 determines the state of the engine requested by the driver based on the opening of the throttle valve 25 detected by the throttle opening sensor 58. The state to be determined is mainly whether it is an idle state or an acceleration / deceleration state.

  The ignition timing correction means 107 corrects the optimum basic ignition timing set by the basic ignition timing setting means 105 according to the state of the engine determined by the acceleration / deceleration determination means 106.

  The target air-fuel ratio setting means 108 sets the optimum target air-fuel ratio in each region of the engine by map search or the like based on the engine speed and the engine load described above.

  The air-fuel ratio feedback control coefficient calculating means 109 performs fuel feedback control based on the output of the oxygen concentration sensor 57 so as to obtain the target air-fuel ratio determined by the ignition timing correcting means 107, and calculates the air-fuel ratio feedback coefficient. At the same time, an equivalent ratio required for calculating the target fuel injection amount is calculated by dividing the theoretical air-fuel ratio and the actual air-fuel ratio.

  FIG. 4 is a functional block diagram showing an outline of the fuel injection control of the present embodiment. Here, the fuel weight that can contribute to the next combustion in the cylinder by calculating the target fuel injection amount and calculating the fuel correction amount. (Fuel evaporation amount) is predicted, the difference from the target fuel injection amount is corrected, and the fuel injection amount is calculated. Specifically, a target fuel injection amount calculation model 201 for calculating a target fuel injection amount based on the engine speed, the equivalence ratio, and the cylinder inflow air amount, the engine speed, the equivalence ratio, the cylinder inflow air amount, the intake pipe pressure ( Port temperature, port temperature for estimating cylinder head temperature based on engine load), cylinder head temperature estimation model 202, target fuel injection amount from target fuel injection amount calculation model 201, port temperature, cylinder head temperature (all are estimated) Value), intake pipe pressure (engine load), and intake valve advance angle amount, and a next combustion contribution fuel amount estimation model 203 that estimates the next combustion contribution fuel amount.

  FIG. 5 is a flowchart showing the processing contents of the target fuel injection amount calculation model 201 shown in FIG. Here, in step 501, various variables are initialized, the initial value of the variable related to the air amount is set to 0, and the initial value of the variable related to pressure is set to atmospheric pressure. Further, the initial value of the temperature-related variable is set to a predetermined value. In step 502, the engine speed HNDATA is acquired from the crank angle sensor 55. In step 503, the cylinder inflow air amount QAR [g / min] calculated from the amount of air passing through the throttle measured by the air flow sensor 53 and the intake pipe pressure is captured. In step 504, the in-cylinder inflow fresh air amount CYLAIR [mg / cyl] is calculated by the following equation (1).

CYLAIR = QAR × 2000 / CYLINFO # / HNDATA (1)
Where QAR: cylinder inflow air amount [g / min]
CYLINFO #: Number of engine cylinders [-]
HNDATA: Engine speed [r / min]

  In addition, what added "#" after the name by an alphabetic character shall memorize | store a value in CPU beforehand as a ROM constant.

  In step 505, the equivalence ratio EQVRTIO is taken in, and in step 506, the target fuel injection amount RQCYLFUEL [mg / cyl] is calculated by the following equation (2).

RQCYLFUEL = CYLAIR / STOICH # × EQVRTIO (2)
Where CYLAIR: amount of fresh air flowing into the cylinder [mg / cyl]
STOICH #: Theoretical air-fuel ratio [-]
EQVRTIO: equivalent ratio [-]

  FIG. 6 is a block diagram showing the processing contents of the port temperature / cylinder head temperature estimation model 202 shown in FIG. 4, and the average effective gas temperature is estimated from the intake pipe pressure, engine speed, ignition timing, and equivalence ratio ( The average effective gas temperature estimation model 601), the cylinder head temperature is estimated from the average effective gas temperature estimation value, the cylinder inflow air amount and the engine water temperature (cylinder head temperature estimation model 602), and the port is determined from the cylinder head temperature and the engine water temperature. The temperature is estimated (port temperature estimation model 603).

  Next, the processing contents shown in the block diagram of FIG. 6 will be described more specifically with reference to the flowcharts of FIGS.

  FIG. 7 is a flowchart showing the processing contents of the average effective gas temperature estimation model 601 in FIG. Here, in step 701, the engine speed HNDATA is fetched, in step 702 the port temperature PRTEMP [Z] calculated last time is fetched, in step 703 the ignition timing ADVS is fetched, in step 704 the equivalence ratio EQVRTIO is fetched, and in step 705 The intake pipe pressure LDATAD [kPa], which is basic information necessary for calculating the indicated mean effective pressure, is taken in. Here, the intake pipe pressure uses the output value of the intake pressure sensor 52, but may be calculated based on the intake air amount of the engine.

  In step 706, the indicated mean effective pressure PME [bar] is calculated by the following equation (3).

PME = LDATAD x KPME + PMEOFS (3)
Where LDATAD: Intake pipe pressure [kPa]
KPME: Calculated mean effective pressure coefficient [bar / kPa]
PMEOFS: Mean effective pressure offset [bar]
In step 707, the average effective gas temperature GASTTEMP [° C.] is calculated by the following equation (4).

GASTTEMP = CGASTMP + PME × KGASTMP × kgasne /
EQVRTIO + prtempcf + advtmpcf (4)
Here, CGASTemp: average gas temperature calculation coefficient [° C.]
PME: Indicated mean effective pressure [bar]
KGASTEMP: Average gas temperature offset value [° C / bar]
EQVRTIO: equivalent ratio [-]
kgasne: Combustion temperature rotational speed correction [-]
prtempcf: Heat transfer from port wall temperature [-]
advtmpcf: Combustion temperature ignition correction [-]
Note that kgasne is a table reference value with the engine speed HNDATA as an axis, and advtmpcf is a table reference value with the ignition timing ADVS as an axis.

  Further, the heat transfer prtempcf from the port wall temperature is obtained by the following equation (5).

  prtempcf = 0.3 × (PRTEMP [Z] −27) (5) where PRTEMP [Z] is the previous calculated port temperature.

  Thus, the average effective gas temperature is determined by the heat transfer factor from the indicated average effective pressure, engine speed, equivalence ratio, ignition timing, and port wall temperature.

  FIG. 8 is a flowchart showing the processing contents of the cylinder head temperature estimation model 602 in FIG. Here, in step 801, the engine water temperature TWN is taken from the water temperature sensor, and in step 802, the cooling water amount WATFLOW [Kg / min] is calculated from a table in which the characteristic data of the thermostat is set with the engine water temperature TWN as an axis. In step 803, the heat release amount HEATRNS to the cooling water is calculated by the following equation (6).

HEATRNS = QAR x heatrnsb (6)
Where QAR: cylinder inflow air amount [g / min]
heatrnsb: Heat transfer to cooling water [-]
Note that heatrnsb is a table reference value with the cooling water amount WATFLOW as an axis.

  Thus, the heat release amount HEATRNS to the cooling water is determined by the factors of the thermostat water amount (engine water temperature) and the cylinder inflow air amount.

  Next, in step 804, the cylinder inflow air amount QAR is taken in, in step 805, the average effective gas temperature GASTTEMP is taken in. In step 806, the target cylinder head temperature TGHDTEMP is calculated by the following equation (7). .

TGHDTEMP = (TWN + GASTTEMP × HEATRNS) / (1+
HEATRNS) (7)
Where TWN: engine water temperature [° C]
GASTemp: Average effective gas temperature [° C]
HEATRNS: Heat dissipation to cooling water [-]
Thus, the target cylinder head temperature is determined by the average effective gas temperature and the heat radiation to the cooling water.

  In step 807, the cylinder head temperature HDTEMP [° C.] is calculated. The cylinder head temperature HDTEMP is calculated by the following equation (8) as a first-order lag of the target cylinder head temperature TGHDTEMP.

HDTEMP = TGHDTEMP × KHDTEMP + (1-KHDTEMP) ×
HDTEMP [Z] (8)
Where TGHDTEMP: target cylinder head temperature [° C.]
KHDTEMP: Cylinder head temperature weighted average filter value [-]
HDTEMP [Z]: Last calculated value of cylinder head temperature [° C]
(Initial value of cylinder head temperature is engine water temperature TWN)

  FIG. 9 is a flowchart showing the processing contents of the port temperature estimation model 603 in FIG. Here, in step 901, the engine water temperature TWN is fetched, in step 902, the above-described cylinder head temperature HDTEMP is fetched, and in step 903, the target port temperature TGPRTMP [° C.] is calculated by the following equation (9).

TGPRTMP = DLTMPPRT1 × (HDTEMP-TWN)
+ TWN (9)
Here, DLTMPPRT1: Port temperature gradient correction value [-]
HDTEMP: Cylinder head temperature [° C]
Thus, the target port temperature is determined by the cylinder head temperature and the heat radiation to the cooling water.

  In step 904, the port temperature PRTEMP [° C.] is calculated. The port temperature PRTEMP is calculated by the following equation (10) as a first-order lag of the target port temperature TGPRTMP.

PRTEMP = TGPRTMP × KPRTTEMP + (1−KPRTTMP)
× PRTEMP [Z] (10)
Where TGPRTMP: target port temperature [° C]
KPRTTEMP: Port temperature weighted average filter [-]
PRTEMP [Z]: Last calculated port temperature [° C]
(The initial value of the port temperature is the engine water temperature TWN)

  FIG. 10 is a block diagram showing an outline of processing of the next combustion contribution fuel amount estimation model 203 in FIG. 4 described above. The processing contents of the control flow according to this block diagram will be described below with further detailed block diagrams and flowcharts.

  A block 1001 (fuel injection amount calculation means when executing synchronous injection) calculates the fuel injection amount when executing synchronous injection, which will be described in detail later.

  In block 1002 (synchronous injection port part fuel adhesion amount calculating means), the synchronous injection port part fuel adhesion amount is calculated. This will be described below.

  FIG. 11 is a block diagram showing a detailed configuration example of the synchronous fuel injection port portion fuel adhesion amount calculating means 1002 in FIG. In block 1101, the above-described port temperature PRTEMP is fetched, and the intake port adhesion rate TTWPRTIN is searched in a table. In block 1102, the intake pipe pressure LDATAD described above is taken in and a table search is performed for the intake port adhesion rate pressure correction TPMPRTIN. In block 1103, the cylinder inflow air amount QAR is taken in, and the intake port adhesion rate air amount correction TQAPRITIN is searched. The multiplier 1104 multiplies the table search values in the blocks 1101 to 1103 to calculate the port portion fuel adhesion rate KFPORTIN at the time of synchronous injection by the following equation (11).

KFPOTIN = TTWPRTIN x TMPPRITIN x
TQAPTIN (11)
Where TTWPRTIN: Intake port adhesion rate [-]
(Search value of table with port temperature PRTEMP as axis)
TPMPRTIN: Inlet port adhesion rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)
TQAPRIN: Inlet port attachment rate air amount correction [-]
(Search value of table with cylinder inflow air amount QAR as axis)

  The multiplier 1105 takes in the fuel injection amount INJFUEL1S at the time of executing synchronous injection, and multiplies it with the above-mentioned KFPORTIN to calculate the port portion fuel adhesion amount PORTTINWL by the following equation (12).

PORTINWL1 = INJFUEL1S × KFPORTIN (12)
Here, INJFUEL1S: fuel injection amount at the time of executing synchronous injection [mg / cyl]
KFPORTIN: Port fuel adhesion during simultaneous injection [-]

  As described above, the amount of fuel adhering to the port at the time of synchronous injection is determined by factors of the port temperature, the intake pipe pressure, and the air amount.

  In block 1003, the previous calculation of the asynchronous fuel injection amount is captured.

  In block 1004, the amount of fuel adhering to the port during asynchronous injection is calculated. This will be described below.

  FIG. 12 is a block diagram showing a detailed configuration example of the port portion fuel adhesion amount calculation means 1004 at the time of asynchronous injection in FIG. In block 1201, the above-described port temperature PRTEMP is fetched, and the intake port adhesion rate TTWCYLIN is searched in a table. In block 1202, the cylinder inflow air amount QAR is taken in and the intake port adhesion rate air amount correction TQACYLIN is searched. Multiplier 1203 multiplies each of the table search values in blocks 1201 and 1202 to calculate port portion fuel adhesion rate KFCYLTIN at the time of asynchronous injection by the following equation (13).

KFCYLIN = TTWCYLIN x TQACYLIN (13)
Here, TTWCYLIN: Asynchronous injection intake port adhesion rate water temperature correction [-]
(Reference value of table with port temperature PRTEMP as axis)
TQACYLIN: Asynchronous injection intake port adhesion rate [-]
(Reference value of table with cylinder inflow air quantity QAR as axis)

  The multiplier 1204 takes in the previously calculated value IRQFUEL1 [Z] of the asynchronous fuel injection amount and multiplies it with the above-mentioned KFCCYLIN to obtain the port portion fuel adhesion amount PORTTINWL1 [mg / cyl] at the time of asynchronous injection by the following equation (14) calculate.

PORTINWLQ1 = IRQFUEL1 [Z] × KFCYLIN (14) where IRQFUEL1 [Z]: the previous calculation value of the injector injection amount (asynchronous injection) [mg / cyl]
KFCYLIN: (Non-simultaneous injection) Port fuel adhesion rate [-]

  As described above, the amount of fuel adhering to the port during asynchronous injection is determined by the factors of the port temperature and the amount of air.

  In block 1005, the port portion fuel liquid film amount PORTFWL1 is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 13 is a flowchart showing a detailed configuration example of the port portion fuel liquid film amount calculating means 1005 in FIG. In step 1301, it is determined whether or not synchronous injection is to be performed. If synchronous injection is to be performed, the flow proceeds to step 1302 and a portion of the synchronously injected fuel adheres to the port portion, so the port portion fuel liquid film amount PORTFWL1 [ mg / cyl] is calculated by the following equation (15).

PORTFWL1 = PORTTFWL1 [Z] + PORTINWL1 (15)
PORTFWL1 [Z]: Last calculated value of port portion fuel liquid film amount [mg / cyl]
PORTINWL1: Normal injection port fuel deposit amount [mg / cyl]

  On the other hand, if synchronous injection is not executed, it is determined whether or not asynchronous injection is executed in step 1303. If asynchronous injection is executed, the process proceeds to step 1304, and part of the asynchronous injection fuel adheres to the port portion. The port portion fuel liquid film amount PORTTFWL1 [mg / cyl] is obtained by the following equation (16).

PORTFWL1 = PORTTFWL1 [Z] + PORTINWLQ1 (16)
PORTFWL1 [Z]: Last calculated value of port portion fuel liquid film amount [mg / cyl]
PORTINWLQ1: Asynchronous injection port fuel deposit [mg / cyl]

  If asynchronous injection is not executed, it is determined in step 1305 whether or not the intake stroke has been completed. If the intake stroke has been completed, the flow proceeds to step 1306 where the port portion liquid film amount is taken away into the cylinder. In consideration of the decrease in the liquid film amount due to evaporation, the port portion fuel liquid film amount PORTFWL1 [mg / cyl] is calculated by the following equation (17).

PORTFWL1 = PORTFWL1 [Z] -CYLINPFWL1-DPORTVPR1 (17)
PORTFWL1 [Z]: Last calculated value of port portion fuel liquid film amount [mg / cyl]
CYLINPFWL1: Fuel flowing into the cylinder [mg / cyl]
DPORTVPR1: Estimated port fuel evaporation [mg / cyl]

  If the intake stroke has not ended, the routine proceeds to step 1307, where the value of the port portion fuel liquid film amount PORTFWL1 [mg / cyl] is held by the following equation (18).

PORTFWL1 = PORTTFWL1 [Z] (18)
PORTFWL1 [Z]: Last calculated value of port portion fuel liquid film amount [mg / cyl]

  In block 1006, the port fuel evaporation amount is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 14 is a block diagram showing a detailed configuration example of the port portion fuel evaporation amount calculating means 1006 in FIG. In block 1401, the above-described port temperature PRTEMP is fetched, and the port portion fuel evaporation rate TTWPORT is searched in a table. In block 1402, the intake pipe pressure LDATAD is taken and a table search is performed for the fuel evaporation rate pressure correction TKPMPORT. In block 1403, the intake valve advance angle value IN_RLVVT is taken in and the fuel evaporation rate intake VTC correction TTAPORT is retrieved. The multiplier 1404 multiplies each of the table search values in the blocks 1401 to 1403 by the evaporation time VPRTIM to calculate the cylinder part fuel evaporation rate KPORTVPR by the following equation (19).

KPORTVPR = VPRTIM x TTWPORT x TKPMPORT
× TTAPORT (19)
Where VPRTIM: Evaporation time [-]
TTWPORT: Port fuel evaporation rate [-]
(Search value of table with port temperature PRTEMP as axis)
TKPMPORT: Fuel evaporation rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)
TTAPORT: Fuel evaporation rate intake VTC correction [-]
(Table search value with intake valve advance value IN_RLVVT as axis)
Note that the VPRTIM sets data in advance for the time during which fuel evaporates at the air temperature during the intake compression stroke.

  The multiplier 1405 takes in the port portion fuel liquid film amount PORTFWL1 and multiplies the port portion fuel liquid film amount PORTFWL1 by the aforementioned KPORTVPR to calculate the port portion fuel evaporation amount DPORTVPR1 [mg / cyl] by the following equation (20).

DPORTVPR = PORTFWL1 × KPORTVPR (20)
PORTFWL1: Port portion fuel film amount [mg / cyl]
KPORTVPR: Cylinder fuel evaporation rate [-]
However, the switch 1406 outputs the above calculated value at the end of the intake stroke, but when it is not at the end of the intake stroke, the port portion fuel evaporation amount DPORTVPR1 outputs the previous value via the 1 / Z block 1407 ( Value).

DPORTVPR = DPORTVPR [Z] (21)
Here, DPORTVPR [Z]: previous calculated value of port portion fuel evaporation [mg / cyl]

  As described above, the port fuel evaporation amount is determined by the factors of the evaporation time, port temperature, intake pipe pressure, and intake valve advance value.

  In block 1007, the next combustion contributing port evaporation amount is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 15 is a flowchart showing a detailed configuration example of the port portion fuel liquid film amount calculating means 1007 in FIG. In step 1501, it is determined whether or not synchronous injection is to be executed. If synchronous injection is to be executed, the process proceeds to step 1502, and the next combustion contribution port portion evaporation amount PORTVPR1 [mg / cyl] is calculated by the following equation (22). To do.

PORTTVPR1 = INJFUEL1S-PORTINWL1
+ DPORTVPR1 (22)
Here, INJFUEL1S: fuel injection amount at the time of executing synchronous injection [mg / cyl]
PORTTINWL1: Port fuel adhesion amount during synchronous injection [mg / cyl]
DPORTVPR1: Port fuel evaporation [mg / cyl]
When the synchronous injection is not executed, the process proceeds to step 1503, and the value of the next combustion contribution port portion evaporation amount PORTVPR1 [mg / cyl] is held.

PORTTVPR1 = PORTTVPR1 [Z] (23)
Here, PORTVPR1 [Z]: The previous calculated value of the next combustion contributing port evaporation amount

  In block 1008, the fuel flowing into the cylinder is calculated, which will be described below with reference to the block diagram of FIG.

  FIG. 16 is a block diagram showing a detailed configuration example of the inflow fuel calculating means 1008 in FIG. In block 1601, the above-described port temperature PRTEMP is fetched, and the port fuel removal rate TTWPRTOUT is searched in a table. In block 1602, the intake pipe pressure LDATAAD is taken in, and a table search is performed for the port fuel removal rate pressure correction TPMPRTOUT. In block 1603, the cylinder inflow air amount QAR is fetched, and the port part fuel carry-off rate air amount correction TQAPRTOUT is searched in a table. The multiplier 1604 multiplies the table search values in the blocks 1601 to 1603 to calculate the cylinder inflow rate KFPORTOUT by the following equation (24).

KFPORTOUT = TTWPRTOUT × TPMPRTOUT
× TQAPRTOUT (24)
TTWPRTOUT: Port fuel removal rate [-]
(Search value of table with port temperature PRTEMP as axis)
TPMPRTOUT: Port fuel removal rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)
TQAPRTOUT: Port fuel removal rate air amount correction [-]
(Search value of table with cylinder inflow air amount QAR as axis)

  The multiplier 1605 takes in the above-mentioned port portion fuel liquid film amount PORTFWL1 and multiplies it with the above-mentioned KFPORTOUT to calculate the fuel flowing into the cylinder CYLINPFWL1 [mg / cyl] by the following equation (25).

CYLINPFWL1 = PORTFWL1 × KFPORTOUT (25)
PORTFWL1: Port portion fuel film amount [mg / cyl]
KFPORTOUT: Cylinder inflow rate [-]

  As described above, the fuel flowing into the cylinder is determined by the factors of the port temperature, the intake pipe pressure, and the air amount.

  In block 1009, the inflow of the asynchronously injected fuel into the cylinder is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 17 is a flowchart showing a detailed configuration example of the in-cylinder inflow in-cylinder calculation unit 1009 in FIG. In step 1701, it is determined whether or not asynchronous injection is to be executed. If asynchronous injection is to be executed, the routine proceeds to step 1702 where the inflow of the asynchronously injected fuel into the cylinder CYLINFL1 [mg / cyl] is expressed by the following equation (26). calculate.

CYLINFL1 = (IRQFUEL1-PORTINWLQ1
+ CYLINFL1 [Z]) × KIRQFCIN # (26)
Here, IRQFUEL1: Injector injection amount (asynchronous injection) [mg / cyl]
PORTINWLQ1: Asynchronous injection port fuel deposit [mg / cyl]
CYLINFL1 [Z]: Previously calculated value of the amount of asynchronous fuel injected into the cylinder [mg / cyl]
KIRQFCIN #: Calculation factor for inflow into cylinder

  If the asynchronous injection is not executed, it is determined in step 1703 whether or not the previous injection has been executed. If the previous injection has been executed, the process proceeds to step 1704, where the inflow of the asynchronously injected fuel into the cylinder CYLINFL1 [mg / cyl] is calculated. It is assumed that CYLINFL1 = 0.

  If the previous injection has not been executed, the value of CYLINFL1 [mg / cyl] of the inflow into the cylinder of the asynchronous injection fuel is held.

CYLINFL1 = CYLINFL1 [Z] (27)
Here, CYLINFL1 [Z]: the previously calculated value of the inflow of the asynchronously injected fuel into the cylinder [mg / cyl]

  In block 1010, cylinder inflow liquid film fuel is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 18 is a flowchart showing a detailed configuration example of the cylinder inflow liquid film fuel calculating unit 1010 in FIG. In step 1801, it is determined whether or not the intake stroke is completed. If the intake stroke is completed, the process proceeds to step 1802, where the portion of the port portion liquid film fuel carried away and the asynchronous injection flows into the cylinder in a liquid state. The cylinder inflow liquid film fuel CYLFUEL1 [mg / cyl] is calculated by the following equation (28).

CYLFUEL1 = CYLINPFWL1 + CYLINFL1 (28)
Here, CYLINPFWL1: Fuel flowing into the cylinder [mg / cyl]
CYLINFL1: Asynchronous injected fuel in-cylinder inflow [mg / cyl]
If the intake stroke has not ended, the routine proceeds to step 1803, where the value of the cylinder inflow liquid film fuel CYLFUEL1 [mg / cyl] is held.

CYLFUEL1 = CYLFUEL1 [Z] (29)
Here, CYLFUEL1 [Z]: the previously calculated value of the cylinder inflow liquid film fuel [mg / cyl]

  In block 1011, a cylinder inflow liquid film fuel adhesion amount is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 19 is a block diagram illustrating a detailed configuration example of the cylinder inflow liquid film fuel adhesion amount calculation unit 1011 in FIG. 10. In block 1901, the above-described cylinder head temperature HDTEMP is taken in, and a table search is performed for the cylinder inflow fuel head portion adhesion rate TTWTURB. In block 1902, the intake pipe pressure LDATAD is taken, and the cylinder inflow fuel head adhesion rate pressure correction TTPMTURB is searched in a table. In block 1903, the cylinder inflow air amount QAR is taken and the cylinder inflow fuel head portion adhesion rate air amount correction TQATURB is searched in a table. In block 1904, the intake valve advance value IN_RLVVT is fetched, and a table search is performed for the cylinder inflow fuel head portion adhesion rate VTC correction TVTCTURB. The multiplier 1905 multiplies the table search values in the blocks 1901 to 1905 to calculate the cylinder part fuel adhesion rate KCYLTURB by the following equation (30).

KCYLTURB = TTWTURB × TTPMTURB × TQATURB × TV TCTURB (30)
Here, TTWTURB: cylinder inflow fuel head adhesion rate [-]
(Table search value with cylinder head temperature HDTEMP as axis)
TTPMTURB: Cylinder inflow fuel head adhesion rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)
TQATURB: cylinder inflow fuel head adhesion rate air amount correction [-]
(Search value of table with cylinder inflow air amount QAR as axis)
TVTCTURB: cylinder inflow fuel head adhesion rate VTC correction [-]
(Table search value with intake valve advance value IN_RLVVT as axis)

  The multiplier 1906 takes in the above-mentioned cylinder inflow liquid film fuel CYLFUEL1 and multiplies it with the above-mentioned KCYLTURB to calculate the cylinder inflow liquid film fuel adhesion amount CYLINWL1 [mg / cyl] by the following equation (31).

CYLINWL1 = CYLFUEL1 × KCYLTURB (31)
Here, CYLFUEL1: Cylinder inflow liquid film fuel [mg / cyl]
KCYLTURB: Cylinder fuel adhesion rate [-]

  As described above, the cylinder inflow liquid film fuel deposition amount is determined by factors such as cylinder head temperature, intake pipe pressure, air amount, and intake valve advance amount.

  In block 1012, the cylinder wall surface adhesion amount is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 20 is a block diagram illustrating a detailed configuration example of the cylinder wall surface adhesion amount calculating unit 1012 in FIG. In block 2001, the above-described cylinder head temperature HDTEMP is taken in, and a table search is performed for the cylinder discharge rate head temperature correction TKPMEXTFW. In block 2002, the intake pipe pressure LDATAAD is taken and the cylinder discharge rate pressure correction TKTWEXTFW is retrieved from the table. The multiplier 2003 multiplies each of the table search values in the blocks 2001 and 2002 to calculate the cylinder portion inflow fuel floating rate KFCYLOUT by the following equation (32).

KFCYLOUT = TKPMEXTFW × TKTWEXTFW (32)
Here, TKPMEXTFW: cylinder discharge rate head temperature correction [-]
(Table search value with cylinder head temperature HDTEMP as axis)
TKTWEXTFW: cylinder discharge rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)

  In the adder 2004, the above-described cylinder inflow liquid film fuel deposition amount CYLINWL1, the above-described cylinder fuel evaporation amount DCYLVPR1, the above-described KFCYLOUT in the multiplier 2005, and the previous value of the cylinder inner wall surface deposition amount via the block 2006, And the previous value of the cylinder inner wall surface adhesion amount are taken in, and the cylinder wall surface adhesion amount CYLFWL1 [mg / cyl] is calculated by the following equation (33).

CYLFWL1 = CYLINWL1-DCYLVPR1-KFCYLOUT
× CYLFWL1 [Z] + CYLFWL1 [Z] (33)
CYLINWL1: Cylinder inflow liquid film fuel deposition amount [mg / cyl]
DCYLVPR1: Cylinder fuel evaporation [mg / cyl]
KFCYLOUT: Cylinder inflow fuel floating rate [-]
CYLFWL1 [Z]: Previously calculated value of the cylinder wall surface adhesion amount [mg / cyl]

  However, the above-described calculated value is output by the switch 2007 at the end of the intake stroke, but when it is not at the end of the intake stroke, the cylinder inner wall surface adhesion amount CYLFWL1 outputs the previous value via the 1 / Z block 2006 ( Value).

CYLFWL1 = CYLFWL1 [Z] (34)
Here, CYLFWL1 [Z]: Previously calculated value of the cylinder inner wall surface adhesion [mg / cyl]

  As described above, the cylinder inner wall surface adhesion amount is determined by the factors of the cylinder head temperature and the intake pipe pressure.

  In block 1013, the cylinder fuel evaporation is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 21 is a block diagram showing a detailed configuration example of the cylinder part fuel evaporation amount calculation means 1013 in FIG. In block 2101, the above-described cylinder head temperature HDTEMP is taken in, and a table search is performed for the cylinder liquid film fuel evaporation rate TTWCYL. In block 2102, the intake pipe pressure LDATAD is taken in, and a table search is performed for the cylinder liquid film fuel evaporation rate pressure correction TTPMCYL. The multiplier 2103 multiplies the table search values in the blocks 2101 and 2102 by the evaporation time VPRTIM described above to calculate the cylinder fuel evaporation rate KCYLVPR by the following equation (35).

KCYLVPR = VPRTIM × TTWCYL × TTPMCYL (35)
Where VPRTIM: Evaporation time [-]
TTWCYL: Cylinder liquid film fuel evaporation rate [-]
(Table search value with cylinder head temperature HDTEMP as axis)
TTPMCYL: Cylinder liquid film fuel evaporation rate pressure correction [-]
(Search value of table with intake pipe pressure LDATAAD as axis)
The multiplier 2104 takes in the cylinder wall surface adhesion amount CYLFWL1 and multiplies it with the above-mentioned KCYLVPR to calculate the cylinder fuel evaporation amount DCYLVPR1 [mg / cyl] by the following equation 836).

DCYLVPR1 = CYLFWL1 × KCYLVPR (36)
Here, CYLFWL1: cylinder wall surface adhesion amount [mg / cyl]
KCYLVPR: Cylinder fuel evaporation rate [-]
However, the switch 2105 outputs the aforementioned calculated value at the end of the intake stroke, but when it is not at the end of the intake stroke, the cylinder fuel evaporation amount DCYLVPR1 outputs the previous value via the 1 / Z block 2106 ( Value).

DCYLVPR1 = DCYLVPR1 [Z] (37)
Here, DCYLVPR1 [Z]: the previously calculated value of the cylinder fuel evaporation [mg / cyl]

  As described above, the cylinder fuel evaporation amount is determined by the factors of the cylinder head temperature and the intake pipe pressure.

  In block 1014, the next combustion contribution cylinder part evaporation amount is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 22 is a block diagram showing a detailed configuration example of the next combustion contribution cylinder part evaporation amount calculation means 1014 in FIG. The adder 2201 takes in the cylinder inflow liquid film fuel CYLFUEL1, the cylinder inflow liquid film fuel adhesion amount CYLINWL1, and the cylinder part fuel evaporation amount DCYLVPR1, and calculates the next combustion contribution cylinder part evaporation amount CYLVPR1 by the following equation (38). calculate.

CYLVPR1 = CYLFUEL1-CYLINWL1
+ DCYLVPR1 (38)
Here, CYLFUEL1: Cylinder inflow liquid film fuel [mg / cyl]
CYLINWL1: Cylinder inflow liquid film fuel deposition amount [mg / cyl]
DCYLVPR1: Cylinder fuel evaporation [mg / cyl]

  However, the switch 2202 outputs the above-mentioned calculated value at the end of the intake stroke, but when it is not at the end of the intake stroke, the next combustion contribution cylinder portion evaporation amount CYLVPR1 outputs the previous value via the 1 / Z block 2203. Yes (retains value).

CYLVPR1 = CYLVPR1 [Z] (39)
Here, CYLVPR1 [Z]: previous calculated value of the next combustion contributing cylinder part evaporation [mg /
cyl]

  In block 1015, the next combustion contribution fuel amount is calculated. This will be described below with reference to the block diagram of FIG.

  FIG. 23 is a block diagram showing a detailed configuration example of the next combustion contribution fuel amount calculation means 1015 in FIG.

  The adder 2301 adds the next combustion contribution port portion evaporation amount PORTVPR1 and the next combustion contribution cylinder portion evaporation amount CYLVPR1 to calculate the next combustion contribution fuel amount CMBFUEL1 by the following equation (40).

CMBFUEL1 = PORTVPR1 + CYLVPR1 (40)
Here, PORTTVPR1: next combustion contributing port evaporation amount [mg / cyl]
CYLVPR1: Next combustion contribution cylinder part evaporation [mg / cyl]

  In block 1016, the target fuel injection amount RQCYLFUEL described above is captured.

  In block 1017, a synchronous fuel injection amount is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 24 is a flowchart showing a detailed configuration example of the synchronous fuel injection amount calculating means 1017 in FIG. In step 2401, the stroke information STROKE1 is captured. Here, the stroke information STROKE1 is updated at the start of each of the intake, compression, expansion, and exhaust strokes, and is calculated from the crank angle sensor. In step 2402, it is determined whether or not the stroke information has changed. If the stroke information has not changed, the flow proceeds to step 2403, and the value of the synchronous fuel injection amount INJFUEL1 [mg / cyl] is held.

INJFUEL1 = INJFUEL1 [Z] (41)
Here, INJFUEL1 [Z]: the previously calculated value of the synchronous fuel injection amount [mg / cyl]

  If the stroke information has changed, the process proceeds to step 2404, where it is determined whether or not there is a fuel cut request. If there is a fuel cut request, the process proceeds to step 2405 and the value of the synchronous fuel injection amount INJFUEL1 [mg / cyl] is set. 0.

  Here, the fuel cut request is a flag that is established when a predetermined engine state that requires fuel cut is reached, for example, at a high engine speed or at a high vehicle speed.

  If there is no fuel cut request, the process proceeds to step 2406, and the synchronous fuel injection amount INJFUEL1 [mg / cyl] is calculated by the following equation (42).

INJFUEL1 = (RQCYLFUEL-CMBFUEL1) / (1-KFPORTIN) + INJFUEL1 [Z] (42)
Here, RQCYLFUEL: target fuel injection amount [mg / cyl]
CMBFUEL1: Fuel contribution to combustion next time [mg / cyl]
KFPORTIN: Port fuel deposition rate during synchronous injection [-]
INJFUEL1 [Z]: Previously calculated value of synchronous fuel injection amount [mg / cyl]

  As described above, the synchronous fuel injection amount is obtained by performing an increase correction for the amount of adhering port to the difference between the target fuel injection amount and the next combustion contribution fuel amount.

  FIG. 25 is a flowchart showing a detailed configuration example of the fuel injection amount calculating means 1001 at the time of executing synchronous injection in FIG. In step 2501, the above-described synchronous fuel injection amount INJFUEL1 is fetched. In step 2502, it is determined whether or not synchronous injection is to be executed. If synchronous injection is to be executed, the flow proceeds to step 2503, where the fuel injection amount INJFUEL1S [ mg / cyl] is calculated by the following equation (43).

INJFUEL1S = INJFUEL1 (43)
Where INJFUEL1: synchronous fuel injection amount [mg / cyl]

  When the synchronous injection is not executed, the process proceeds to step 2504, and the value of the fuel injection amount INJFUEL1S [mg / cyl] at the time of executing the synchronous injection is held.

  INJFUEL1S = INJFUEL1S [Z] (44) Here, INJFUEL1S [Z]: the previously calculated value of the fuel injection amount at the time of executing synchronous injection [mg / cyl]

  At block 1018, an asynchronous fuel injection amount is calculated. This will be described below with reference to the flowchart of FIG.

  FIG. 26 is a flowchart showing a detailed configuration example of the asynchronous fuel injection amount calculation means 1018 in FIG. In step 2601, the above-described stroke information STROKE1 is captured. In step 2602, it is determined whether any one of synchronous injection execution, asynchronous injection execution, and compression stroke is established. If yes, the process proceeds to step 2603, and intermediate variable rqcylfuels is calculated by the following equation (45).

rqcylfuels = RQCYLFUEL (45)
Here, RQCYLFUEL: target fuel injection amount [mg / cyl]

  If the condition in step 2602 is not satisfied, the process proceeds to step 2604, and the value of the intermediate variable rqcylfuels is held.

rqcylfuels = rqcylfuels [Z] (46)
In step 2605, the asynchronous fuel injection amount is calculated by the following equation (47).

irqfuel1b = (RQCYLFUEL-rqcylfuels)
/ (1-KFCYLIN) (47) where RQCYLFUEL: target fuel injection amount [mg / cyl]
KFCYLIN: (Non-simultaneous injection) Port fuel adhesion rate [-]

  In step 2606, the aforementioned intermediate variable irqfuel1b is compared with the threshold value IRQFUELGO # to determine whether or not asynchronous injection is to be executed. When the condition of step 2606 is satisfied, the process proceeds to step 2607, where the above-described intermediate variable irqfuel1b is set to the asynchronous fuel injection amount IRQFUEL1 [mg / cyl].

  IRQFUEL1 = irqfuel1b (48)

  If the condition in step 2606 is not satisfied, the process proceeds to step 2608, where the asynchronous fuel injection amount IRQFUEL1 [mg / cyl] is set to IRQFUEL1 = 0.

  As described above, the asynchronous fuel injection amount is obtained by performing an increase correction for the amount of port adhesion on the difference between the target fuel injection amount and the target fuel injection amount when the predetermined condition is satisfied.

  FIG. 27 is a schematic enlarged view of the vicinity of the intake port 29 and the cylinder head 12A of the engine 10 shown in FIG. 1. The port temperature, cylinder head temperature, port portion attached fuel, and cylinder inner wall surface attached fuel described so far are shown. Shown schematically. In this embodiment, the port temperature and the cylinder head temperature are estimated, and the fuel injection amount that contributes to the next combustion is predicted by taking into account the evaporation from the fuel adhering to the port portion and the fuel adhering to the cylinder inner wall, and the fuel injection amount is calculated. Correction / calculation. A sensor may be attached to the illustrated portion to measure the temperature.

  FIG. 29 shows an example of a time chart showing the behavior of each variable when the fuel injection control device 1 including the next combustion contribution fuel amount calculation means of this embodiment controls the engine. The engine speed is assumed to be acceleration / deceleration from 2000 r / min, and the engine water temperature is assumed to be constant at −20 ° C. (A) is the fuel injection amount, (B) is the required fuel amount, (C) is the fuel liquid film amount, (D) is the fuel evaporation amount, and (E) is the behavior of the injection pulse width. (A) represents the behavior of the synchronous fuel injection amount (INJFUEL1) with respect to the solid target fuel injection amount (RQCYLFUEL) by a dotted line. (B) represents the behavior of the next combustion contribution fuel amount (CMBFUEL1) with respect to the solid target fuel injection amount (RQCYLFUEL) by a dotted line. (C) represents the behavior of the port portion liquid film fuel amount (PORTTFWL1) by a solid line, and the behavior of the cylinder wall surface adhesion amount (CYLFWL1) by a dotted line. (D) represents the behavior of the next combustion contribution port portion evaporation amount (PORTTVPR1) by a solid line, and represents the behavior of the next combustion contribution cylinder portion evaporation amount (CYLVPR1) by a dotted line.

  In this embodiment, the port temperature and the cylinder head temperature are estimated, and the port portion liquid film fuel amount (PORTFWL1) and the cylinder inner wall surface adhesion amount (CYLFWL1) are calculated through the functional blocks shown in FIG. The evaporation amount (PORTTVPR1, CYLVPR1) of the contributing port portion and cylinder portion is calculated, the next combustion contributing fuel amount (CMBFUEL1) is calculated, the next combustion contributing fuel amount (CMBFFUEL1), the target fuel injection amount (RQCYLFUEL), and Is corrected, and the synchronous fuel injection amount (INJFUEL1) is calculated. When the above-mentioned synchronous fuel injection amount (INJFUEL1) is converted into an injection pulse width, it is as shown by a dotted line in (E). When the target fuel injection amount (RQCYLFUEL) increases during acceleration or the like, the injection pulse width is shorter in the present embodiment than the injection pulse width of the conventional technology shown by the solid line. Further, when the target fuel injection amount (RQCYLFUEL) decreases during deceleration or the like, the injection pulse width is shorter in the present embodiment than the injection pulse width of the prior art shown by the solid line.

  As described above, in this embodiment, when the acceleration / deceleration is repeated while the engine water temperature is substantially the same, the fuel injection correction amount decreases as time elapses.

FIG. 30 is a time chart showing the behavior of the fuel injection correction amount in this embodiment. As can be seen from the figure, the correction amount changes according to the cylinder head temperature and the port temperature, so that fluctuations in the air-fuel ratio due to the fact that the fuel injection amount correction does not change during repeated acceleration / deceleration with the engine water temperature being substantially the same are suppressed. Is possible. As a result, unnecessary torque fluctuations and deterioration of exhaust emission characteristics can be prevented.
As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. Moreover, each component is not limited to the said structure, unless the characteristic function of this invention is impaired.

The schematic block diagram which shows one Example of the fuel-injection control apparatus which concerns on this invention with an example of the vehicle-mounted engine to which it is applied. Schematic which shows the internal structure of the control unit shown by FIG. The functional block diagram which shows the fuel-injection control outline | summary etc. which a control unit performs. The functional block diagram which shows the outline | summary of the fuel-injection control of an Example. The flowchart which shows the processing content of the target fuel injection amount calculation model 201 shown by FIG. The block diagram which shows the processing content of the port temperature and cylinder head temperature estimation model 202 shown by FIG. The flowchart which shows the processing content of the average effective gas temperature estimation model 601 in FIG. The flowchart which shows the processing content of the cylinder head temperature estimation model 602 in FIG. The flowchart which shows the processing content of the port temperature estimation model 603 in FIG. The block diagram which shows the process outline | summary of the next combustion contribution fuel amount estimation model 203 in FIG. The block diagram which shows the detailed structural example of the port part fuel adhesion amount calculating means 1002 at the time of synchronous injection in FIG. The block diagram which shows the detailed structural example of the port part fuel adhesion amount calculation means 1004 at the time of asynchronous injection in FIG. 11 is a flowchart showing a detailed configuration example of a port portion fuel film amount calculating unit 1005 in FIG. The block diagram which shows the detailed structural example of the port part fuel evaporation amount calculation means 1006 in FIG. The flowchart which shows the detailed structural example of the next process port part fuel liquid film amount calculation means 1007 in FIG. The block diagram which shows the detailed structural example of the inflow fuel calculation means 1008 in FIG. 11 is a flowchart showing a detailed configuration example of the in-cylinder inflow in-cylinder calculation unit 1009 in FIG. 10. The flowchart which shows the detailed structural example of the cylinder inflow liquid film fuel calculation means 1010 in FIG. The block diagram which shows the detailed structural example of the cylinder inflow liquid film fuel adhesion amount calculation means 1011 in FIG. The block diagram which shows the detailed structural example of the cylinder wall surface adhesion amount calculation means 1012 in FIG. The block diagram which shows the detailed structural example of the cylinder part fuel evaporation amount calculation means 1013 in FIG. The block diagram which shows the detailed structural example of the next combustion contribution cylinder part evaporation amount calculation means 1014 in FIG. The block diagram which shows the detailed structural example of the next combustion contribution fuel amount calculation means 1015 in FIG. The flowchart which shows the detailed structural example of the synchronous fuel injection amount calculation means 1017 in FIG. The flowchart which shows the detailed structural example of the fuel injection amount calculation means 1001 at the time of synchronous injection execution in FIG. 11 is a flowchart showing a detailed configuration example of the asynchronous fuel injection amount calculation means 1018 in FIG. FIG. 2 is a schematic enlarged view of the vicinity of an intake port 29 and a cylinder head 12A of the engine 10 shown in FIG. The time chart with which explanation of the subject which the present invention tends to solve is offered. The time chart which shows an example of the behavior of each variable when the fuel-injection control apparatus provided with the next combustion contribution fuel amount calculation means of the Example is controlling the engine. The time chart which shows the behavior of the fuel injection correction amount in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel-injection control apparatus 10 ... Engine 12 ... Cylinder 12A ... Cylinder head 12B ... Cylinder block 17 ... Combustion operation chamber 20 ... Intake passage 29 ... Intake port 30 ... Fuel injection valve 35 ... Spark plug 52 ... Intake pressure sensor 57 ... Oxygen concentration sensor 55 ... Crank angle sensor 58 ... Throttle opening sensor 100 ... Engine control unit (ECU )
DESCRIPTION OF SYMBOLS 102 ... Target fuel injection amount calculation means 103 ... Cylinder head temperature / port temperature estimation means 104 ... Next combustion contribution fuel amount / fuel injection amount calculation means 201 ... Target fuel injection amount calculation model 202 ... -Port temperature, cylinder head temperature estimation model 203 ... Next combustion contribution fuel quantity estimation model

Claims (7)

An engine fuel injection control device provided with a fuel injection valve for injecting fuel toward an intake port,
Target fuel injection amount calculating means for calculating a target fuel injection amount based on the operating state of the engine, head temperature estimating means for estimating the temperature of the cylinder head, port temperature estimating means for estimating the temperature of the intake port, Next combustion that estimates the amount of fuel that contributes to combustion in the combustion cycle starting from the next intake stroke among the fuel remaining in the cylinder and in the intake port based on the cylinder head temperature and the intake port temperature at the end of the intake stroke And a fuel injection amount calculating means for calculating a fuel injection amount to be injected from the fuel injection valve based on the target fuel injection amount and the next combustion contribution fuel amount. Engine fuel injection control device.   The head temperature estimating means estimates an average effective gas temperature based on an operating state of the engine, and estimates a cylinder head temperature based on the estimated average effective gas temperature. Engine fuel injection control device.   The engine fuel injection control device according to claim 1, wherein the port temperature estimation unit estimates the intake port temperature based on the estimated cylinder head temperature.   The next combustion contributing fuel amount estimation means includes means for estimating a port portion evaporation amount contributing to combustion in the next combustion cycle, and means for estimating a cylinder internal evaporation amount contributing to combustion in the next combustion cycle, The engine fuel injection control according to any one of claims 1 to 3, wherein the next combustion contribution fuel amount is estimated based on the next combustion contribution port portion evaporation amount and the next combustion contribution cylinder internal evaporation amount. apparatus.   The next combustion contribution port portion evaporation amount estimation means estimates the next combustion contribution port portion evaporation amount based on a fuel injection amount at the time of executing synchronous injection and a fuel evaporation amount from fuel adhering to the port portion. The engine fuel injection control device according to claim 4.   The next combustion contributing cylinder internal evaporation amount estimating means estimates the cylinder internal evaporation amount based on the fuel amount flowing into the cylinder from the fuel adhering to the intake port portion and the fuel amount evaporating from the inflow fuel in the cylinder. The fuel injection control device for an engine according to claim 4 or 5.   7. The fuel injection correction amount is configured to decrease as time elapses when acceleration / deceleration is repeated in a state where the engine coolant temperature is substantially constant. Engine fuel injection control device.

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