CN104118423B - Engine Power Quantization Function Selection - Google Patents

Abstract

A vehicle having an engine and a traction battery and a method of operating the engine are disclosed. The controller operates the engine based on the quantified engine power level. The level of quantization depends on the total power demand. For lower values of the total power demand, the selected quantization level may be at least equal to the total power demand. For higher values of total power demand, the selected quantization level may be less than or equal to the total power demand. For values between the low and high values, the selected quantization level may be the quantization level closest to the total power demand. The traction battery may receive or provide power according to a selected quantization level.

Description

Engine Power Quantization Function Selection

technical field

The invention relates to a hybrid electric vehicle and a control method thereof.

Background technique

FIG. 1 shows a block diagram of a conventional "load following" engine power determination architecture 10 for a hybrid electric vehicle. In conventional architecture 10 , engine power command 12 is determined as the sum of driver power command 14 and battery power command 16 . Thus, in conventional architecture 10 , the engine responds directly to any changes in driver power command 14 .

Therefore, in actual driving, any disordered or aggressive driver power command 14 can easily generate disturbances in the engine power command 12 . The disturbances can be reflected as rapid fluctuations and jerks in the engine power command 12 . Such transients can adversely affect engine combustion efficiency and consume additional transient fuel. In addition, many engine control parameters are planned “categorically” based on the rate of change of the engine power command 12 . Therefore, engine power disturbances may cause otherwise non-optimal engine settings and exacerbate fuel/air errors. Even if the A/F (air/fuel) ratio can be kept within a moderately narrow range, the combined effect of fuel enrichment caused by more frequently occurring transients can be amplified and accumulate to higher levels of fuel loss.

Contents of the invention

A vehicle is disclosed that includes an engine, a traction battery, and at least one controller. The controller is configured to request power from the engine at least equal to the total power demand such that the traction battery receives power when the total power demand is less than a predetermined value. The controller is configured to request power from the engine to be less than the total power demand when the total power demand is greater than another predetermined value such that the traction battery provides power to meet the total power demand. The controller may also be configured to request power from the engine at a quantified level such that the traction battery receives or provides power according to a difference between the total power demand and the quantified requested power level. The total power demand may be the sum of the driver power demand and the battery power demand. The controller may also be configured to request power from the engine at the selected one of the quantized levels that is closest to the value of the total power demand. The controller may also be configured to: when the total power demand is greater than the predetermined value and less than the other predetermined value, request power from the engine at the quantized level closest to the value of the total power demand. power.

A vehicle is disclosed that includes an engine, a traction battery, and at least one controller. The controller is configured to request power from the engine at a quantified level less than or equal to the total power demand such that the traction battery provides power to meet the total power demand. The total power demand may be the sum of the driver power demand and the battery power demand. The controller may also be configured to request power from the engine at a quantified level at least equal to the total power demand such that the traction battery receives power from the engine when the total power demand is less than a predetermined value. The controller may be further configured to request power from the engine at the selected one of the quantized levels closest to the value of the total power demand when the total power demand is greater than a predetermined value and less than another predetermined value .

A method for operating an engine is disclosed. The method includes: outputting power from the engine at least equal to the total power demand when the total power demand is less than a predetermined value. The method further includes: when the total power demand is greater than another predetermined value, outputting power from the engine is less than the total power demand. The method further includes requesting power from the engine at a selected one of the plurality of quantization levels that is closest to a value of the total power demand when the total power demand is greater than the predetermined value and less than another predetermined value. The method may further include that the total power demand is the sum of the driver power demand and the battery power demand. The method may further include requesting power from the engine at one of the quantized levels closest to a value of the total power demand when the total power demand is less than the predetermined value or greater than the another predetermined value.

The total power demand is the sum of the driver power demand and the battery power demand.

The method further includes: when the total power demand is less than the predetermined value or greater than the other predetermined value, requesting power from the engine at a quantization level selected from a plurality of quantization levels closest to the value of the total power demand power.

Description of drawings

Figure 1 shows a block diagram of a conventional "load following" engine power determination architecture for a hybrid electric vehicle;

Figure 2 shows a schematic diagram of an exemplary hybrid vehicle;

3 shows a block diagram of an improved engine power determination architecture configured to implement a control method for engine transient mitigation in a hybrid vehicle, according to an embodiment of the present invention;

4 shows a flowchart describing the operation of an engine power command quantization and hysteresis routine of a control method for engine transient mitigation;

5 shows a flowchart describing the operation of a quantized engine power command filter routine for a control method for engine transient mitigation;

Fig. 6 shows a graphical representation of one possible embodiment of selecting a quantization function.

detailed description

Embodiments of the disclosure are described herein. It should be understood, however, that the disclosed embodiments are merely examples, and that other embodiments may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As will be understood by those of ordinary skill in the art, features described and shown with reference to any one figure may be combined with features shown in one or more other figures to produce a feature not explicitly shown or described. Example. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desired for particular applications or implementations.

FIG. 2 shows a schematic diagram of one possible embodiment of a hybrid vehicle 20 . The hybrid vehicle 20 includes a first set of wheels 22 , a second set of wheels 24 and a wheel drive system or powertrain 26 .

The powertrain 26 may be configured to drive or actuate the first set of wheels 22 and/or the second set of wheels 24 . The powertrain 26 may have any suitable configuration, such as series drive, split-split hybrid drive, or dual-mode split as known to those skilled in the art. In the embodiment shown in FIG. 2 , powertrain 26 has a powersplit drive configuration.

The powertrain 26 may be configured to drive the first set of wheels 22 and/or the second set of wheels 24 or to provide torque to the first set of wheels 22 and/or the second set of wheels 24 . In the illustrated embodiment, the powertrain 26 is configured to drive the first set of wheels 22 and the electric machine 28 (eg, an electric motor) is configured to drive the second set of wheels 24 . Alternatively, the second wheel set 24 may be provided without the motor 28 .

Hybrid vehicle 20 may include any suitable number of power sources. In the embodiment shown in FIG. 2 , hybrid vehicle 20 includes a primary power source 30 and a secondary power source 32 . Primary power source 30 may be any suitable energy generating device (eg, an internal combustion engine). The secondary power source 32 may be electric, non-electric, or a combination thereof. An electrical power source may be used, for example, a battery, a battery pack with interconnected battery cells, a capacitor, or a fuel cell. If batteries are used, they may be of any suitable type, for example, nickel-metal hydride (Ni-MH), nickel-iron (Ni-Fe), nickel-cadmium (Ni-Cd), lead-acid, bromide Zinc (Zu-Br) or lithium based batteries. If a capacitor is used, the capacitor may be any suitable type of capacitor, eg an ultra capacitor, super capacitor, electrochemical capacitor or electric double layer capacitor. A non-electric power source may be a device whose energy can be converted into electrical or mechanical energy. For example, hydraulic or mechanical power sources (eg, flywheels, springs, motors, or compressed gas) can store energy that can be converted or released as electrical or mechanical energy as needed. For the sake of brevity, the following description will refer primarily to embodiments of the invention that include an electric power source.

Primary power source 30 and secondary power source 32 may be adapted to provide power to power transmission system 34 and/or electric machine 28 . The power transfer system 34 may be adapted to drive one or more wheel sets 22 , 24 . In at least one embodiment, power transfer system 34 may be coupled to differential 36 in any suitable manner (eg, via a drive shaft, chain, or other mechanical linkage). A differential 36 may be coupled to each wheel in the first set of wheels 22 by one or more shafts 38 (eg, axles or half shafts).

Power transfer system 34 may include a number of mechanical, electrical, and/or electromechanical devices. In the illustrated embodiment, the power transfer system 34 includes, as major components, a planetary gear assembly 40 , a first electric machine 42 , a power transfer unit 44 and a second electric machine 46 .

Planetary gear assembly 40 may have any suitable configuration. In the illustrated embodiment, the planetary gear assembly 40 includes a sun gear 50 , a plurality of planet gears 52 , and a ring gear 54 .

Primary power source 30 is selectively coupleable to planetary gear assembly 40 via clutch 56 . Clutch 56 may be any suitable type of clutch, such as a one-way clutch that allows primary power source 30 to drive planetary gear assembly 40 . If clutch 56 is engaged, primary power source 30 may rotate planetary gears 52 . Rotation of the planetary gears 52 then rotates the ring gear 54 . Ring gear 54 may be coupled to power transfer unit 44 coupled to differential 36 for transferring torque to the wheels for propulsion of hybrid vehicle 20 . The power transfer unit 44 may include multiple gear ratios that may be engaged to provide a desired vehicle response.

A first electric machine 42 , which may be an electric motor or a motor-generator, may be coupled to sun gear 50 to provide torque to supplement or counteract that provided by primary power source 30 . A brake 58 may be provided to reduce speed and/or torque or transmission from the first electric machine 42 to the sun gear 50 .

The secondary power source 32 and/or the first electric machine 42 may provide power to the second electric machine 46 . A second electric machine 46 , which may be an electric motor, may be coupled to the power transfer unit 44 to propel the hybrid vehicle 20 .

One or more controllers 60 may monitor and control various aspects of the hybrid vehicle 20 . For simplicity, a single controller 60 is shown; however, multiple controllers may be provided for monitoring and/or controlling the components, systems and functions described herein.

Controller 60 may communicate with primary power source 30, secondary power source 32, and electric machines 42, 46 to monitor and control their operation and performance. Controller 60 may receive signals indicative of engine speed, engine torque, vehicle speed, motor speed, motor torque, and the operating status of secondary power source 32 in a manner known to those skilled in the art. For example, an engine speed sensor may be adapted to detect the rotational speed or rate of rotation of an associated component to detect engine speed. Such a rotational speed sensor may be integrated with the primary power source 30 to detect the rotational speed or rate of rotation of the output shaft of the primary power source. Alternatively, a rotational speed sensor may be provided in the powertrain 26 on the downstream side of the primary power source 30 .

Controller 60 may receive input signals from other components or subsystems. For example, controller 60 may receive a signal indicative of vehicle acceleration requested by the driver or by a vehicle system (eg, an active or smart cruise control system). Such a signal may be provided via or based on a signal from an input device or sensor 62 (eg, an accelerator pedal sensor or a cruise control input device).

Controller 60 may also receive signals indicative of vehicle deceleration requested by the driver or by a vehicle system (eg, an active or smart cruise control system). Such a signal may be provided via or based on a signal from an input device or sensor 64 (eg, a brake pedal sensor or a cruise control input device).

Acceleration and deceleration requests can be used to evaluate whether a "tip-in" event or a "tip-out" event has occurred. A pedal event indicates a need for additional power or vehicle acceleration. A tip-out event indicates that less power is required or that the vehicle is decelerating. For example, actuation of an accelerator pedal may indicate a pedal-in event. Similarly, braking of the vehicle, release of the accelerator pedal, or a combination thereof may indicate a tip-out event.

In a hybrid vehicle, acceleration (pedaling) and deceleration (pedaling) events may result in changes in the power provided to actuate the wheels. Generally, an acceleration request increases the power consumption demand and a deceleration request decreases the power consumption demand. The change in power demand may result in a transient condition or state in which the operating characteristics of at least one power source change to provide an increased or decreased amount of power.

In a hybrid vehicle with an engine, engine power may be a function of engine output torque and engine speed (eg, power (power) = torque x speed). During transient conditions, reduced fuel economy can occur if engine torque and engine speed are not intelligently controlled. Fuel economy disadvantages may be amplified by aggressive driving with more frequent pedal-in and/or tip-off events. The disclosed vehicles and methods may improve fuel economy by providing an enhanced control method compared to existing methods.

FIG. 3 shows a block diagram of one possible embodiment of an improved engine power determination architecture 70 configured to implement a control method for engine transient mitigation in a hybrid vehicle. The improved architecture 70 will be described with reference to an embodiment of a hybrid vehicle having an engine (as the primary power source) and a battery (as the secondary power source); Use other primary and secondary power sources.

A control method for engine transient mitigation includes a routine for quantizing an engine power command and a routine for filtering the engine power command. The purpose of the engine transient mitigation method is to effectively smooth the profile of the engine power command and allow the battery to provide power to fill in the high frequency and noisy parts of the driving power.

Compared to the conventional architecture 10, the improved architecture 70 implements the following additional routines to profile the engine power command: (i) the engine power command quantization and hysteresis routine (described below with reference to FIG. 4 ); (ii) the quantized engine power command Instruction filter routine (described below with reference to FIG. 5).

An improved architecture 70 that may be implemented in controller 60 includes an engine power command quantization and filtering module 72 . In general, module 72 receives as input a raw engine power command (P _tot ) 12 . The engine power command (P _tot ) 12 may then be processed through an engine power command quantization and hysteresis routine and a quantized engine power command filter routine. The resulting output is a smoothed engine power command (P _tot — final ) 74 . In both the conventional architecture 10 and the improved architecture 70 , the engine power command (P _tot ) 12 is determined as the sum of the driver power command 14 and the battery power command 16 . However, the improved architecture 70 outputs a smoothed engine power command (P _tot — final ) 74 (contrasted with the engine power command (P _tot ) 12 ) to determine the engine torque command.

Quantization and filtering module 72 includes quantizer 76 and hysteresis logic 78 . Quantizer 76 and hysteresis logic 78 generate a quantized engine power command (P _tot — quantized ) 80 output based on performing an engine power command quantization and hysteresis routine (described below with reference to FIG. 4 ) on engine power command (P _tot ) 12 .

The quantization and filtering module 72 may also include a program 68 to select a particular quantization function 76 to be used. Quantization selection program 68 may indicate the type of quantization performed under different conditions. Typical quantization functions may include an upper bound function that rounds up to the nearest higher quantization level, a lower bound function that rounds down to the nearest lower quantization level, or rounds up or rounds down to the nearest A rounding function close to the quantization level. Selection of a particular quantization function may depend on the current operating state of the vehicle.

One embodiment of the quantitative selection function 68 may be based on the engine power command (P _tot ) 12 . The engine power command 12 may reflect the total power demand of the vehicle. FIG. 6 shows a possible embodiment of a quantized selection function, where the engine power range is divided into separate sections - a low power zone 200 , an intermediate power zone 202 and a high power zone 204 . These areas can be determined using correctable values to define their extent. Different quantization functions may be selected when the engine power command 12 is within a given region. One possible configuration could be to choose an upper bound function in the low dynamic range, a rounded function in the middle dynamic range and a lower bound function in the high dynamic range. The values defining these ranges can be corrected to provide improvements in fuel economy and performance. Note that the described embodiment is only one possible solution and other embodiments may be chosen.

Referring to FIG. 6 , a low power threshold 206 may be defined as the boundary between the low power region 200 and the intermediate power region 202 . Engine power may be considered to be in the low power region 200 when the engine power command is below the low power threshold 206 . A high power threshold 208 may also be defined, which defines the boundary between the intermediate power region 202 and the high power region 204 . Engine power commands falling between the low power threshold 206 and the high power threshold 208 may be considered to be in the intermediate power region 202 . Finally, engine power commands above the high power threshold 208 may be considered to be in the high power region 204 .

Within each of the regions in FIG. 6 , an exemplary total engine power command is depicted along with a corresponding quantified power command. In the low power region 200, an upper bound function is shown. This graphically shows that the total engine power command signal 210 is quantized to the next higher quantization level (as depicted by quantized power signal 212 ). For the upper bound function, the quantized power command signal 212 will be equal to or higher than the total engine power command signal 210 shown. In the middle power region 202, a rounding function is shown. This graphically shows that the total engine power command signal 214 is rounded to the nearest quantized level (as depicted by the quantized power signal 216 ). In this case, the quantized power signal 216 may be higher or lower than the total engine power command signal 214 depending on the closest quantized level. In the high dynamics region 204 a lower bound function is shown. This graphically shows that the total engine power command signal 220 is quantized to the next lower quantization level (as depicted by quantized power signal 218 ). For the lower bound function, the quantized power command signal 218 will be equal to or lower than the total engine power command signal 220 shown.

For example, an embodiment with a fixed quantization step size (Qntz_Step) can be described as follows:

${\mathrm{<span\; class="notranslate">\; Quantization</span>}}_{\mathrm{<span\; class="notranslate">\; ceiling</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; INT</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}}{{\mathrm{<span\; class="notranslate">\; Qntz</span>}}_{\mathrm{<span\; class="notranslate">\; step</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1.0</span>}<span\; class="notranslate">\; )</span>$ ${\mathrm{<span\; class="notranslate">\; Quantization</span>}}_{\mathrm{<span\; class="notranslate">\; round</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; INT</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}}{{\mathrm{<span\; class="notranslate">\; Qntz</span>}}_{\mathrm{<span\; class="notranslate">\; step</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; Quantization</span>}}_{\mathrm{<span\; class="notranslate">\; floor</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; INT</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; tot</span>}}}{\mathrm{<span\; class="notranslate">\; Qntz</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; step</span>}}<span\; class="notranslate">\; )</span>$

where INT(x) is a function reduced to the nearest integer below value (x) and Qntz_Step is the step size (size) of the quantization level. Note that other embodiments of quantization functions may be possible.

The engine power command (P _tot ) 12 is the sum of the driver power command 14 and the battery power command 16 and may represent the total power demand of the vehicle. The smoothed engine power command (P _tot — final ) 74 may differ from the engine power command 12 after the quantization and filtering module 72 processes the engine power command 12 . Where smoothed engine power command 74 is greater than engine power command 12 , power may be supplied to the battery since the engine may produce more power than required. When the smoothed engine power command 74 is less than the engine power command 12 , the battery may supply power to meet the shortfall in the total power demand.

Referring back now to FIG. 3 , the quantization and filtering module 72 may also include a filter 82 . Filter 82 may perform a quantized engine power command filtering procedure (described below with reference to FIG. 5 ) by using a low pass filter to smooth the difference between the engine power command (P _tot ) 12 and the quantized engine power command (P _{tot_quantized} ) 80 The power difference (ΔP)84. The filter 82 may produce a filtered power difference (ΔP _filtered ) 86 as output. The quantized engine power command (P _tot — quantized ) 80 and the filtered power difference (ΔP _filtered ) 86 may then be summed to produce a smoothed engine power command (P _tot — final ) 74 . A smoothed engine power command (P _tot — final ) 74 may be output from the quantization and filtering module 72 for use in determining an engine torque command.

Filter 82 may be used to smooth power difference (ΔP) 84 using filter constant (Fk) 88 provided by filter determination calculation table 90 of quantization and filtering module 72 to produce filtered power difference (ΔP _filtered ) 86 . As described in more detail below, the filter constant (Fk) 88 may be adaptively determined based on the fuel loss % (Φ) 92 and the magnitude of the power difference (ΔP) 84 . Fuel consumption % (Ф) 92 may be calculated online based on closed loop feedback lambda (11th letter in Greek) A/F ratio.

Figures 4 and 5 illustrate flow diagrams 100 and 130, respectively, which describe possible embodiments of an engine power command quantization and hysteresis routine and a quantized engine power command filtering routine, respectively.

As will be appreciated by those of ordinary skill in the art, flowcharts 100 and 130 represent control logic that may be implemented using hardware, software, or a combination thereof. For example, a programmed microprocessor may be used to perform a number of functions. Control logic may be implemented using any of a number of known programming or processing techniques or strategies and is not limited to the sequence shown. For example, interrupt or event-driven programs are used in real-time control applications instead of the purely sequential strategy shown. Likewise, dual processing, multitasking, or multithreading systems and methods can be used to achieve the objects, features and advantages of the present invention.

The invention is not dependent on a particular programming language, operating system processor or circuitry used to develop and/or implement the control logic shown. Likewise, depending on the particular programming language and processing strategy, various functions may be performed at substantially the same time, in the order shown, or in a different order while achieving the features and advantages of the present invention. Modifications to, or in some cases omission of, illustrated functionality may be made without departing from the spirit or scope of the invention.

Referring now to FIG. 4 , with continued reference to the modified architecture 70 shown in FIG. 3 , there is shown a flowchart 100 describing the operation of the engine power command quantization and hysteresis routine. Quantizer 76 and hysteresis logic 78 of quantization and filtering module 72 carry out this process.

The program provides a power quantization procedure designed to discretize the raw engine power command (P _tot ) 12 into a predetermined (calibrable) grid. As the engine power command (P _tot ) 12 fluctuates within a unit power grid step, the engine power command is held at a quantized constant level to eliminate any rapid changes or jitter. For example, assuming a power quantization grid step size of 5kW, any engine command fluctuations with a "swing" of less than 5kW will be filtered out. Instead, battery power fills the transient demands.

Hysteresis logic is embedded to prevent undesirably rapid switching of quantized engine power commands between two adjacent quantized grids. During a pedal-in event, at iteration n, the "magnitude increase" of the engine power command (P _tot ) 12 exceeds the previous quantified engine power command (recorded from the previous iteration (n-1) ) is higher than the upper threshold, the quantified engine power command can be updated accordingly. Otherwise, the quantized engine power command remains the same as the previous cycle. Similarly, a lower threshold is used in the hysteresis logic for tip-off events.

Operation of the Engine Power Command Quantization and Hysteresis routine begins with setting values for Upper Limit, Lower Limit and Grid Size in block 102 . The grid size value indicates the size of the steps used for each quantization grid. The upper value indicates an engine power command "magnitude increase" threshold for a pedal-in event. The lower limit value indicates an engine power command "magnitude reduction" threshold for a tip-out event.

An optional step of selecting a quantization function may be performed as part of block 102 prior to quantization. Selection of the quantization function may be based on the engine power command (P _tot ) 12 . In block 102, during the current cycle "n", the quantizer 76 quantizes the engine power command (P _tot ) 12 as a function of the grid size to produce a quantized engine power command (P tot ) for the current cycle "n". _{tot_quantized} ). The quantization may be performed by a selected quantization function (which may be an upper bound function, a lower bound function or a rounding function).

In block 104 , the engine power command (P _tot ) 12 is checked to determine if P _tot is greater than zero. If the engine power command (P _tot ) 12 is not greater than zero in box 104, then the quantized engine power command (P _tot — quantized ) 80 is set to the engine power command (P _tot ) 12 in box 106 (ie, P tot — _quantized = P _tot ). If the engine power command (P _tot ) 12 is greater than zero in box 104 , then the routine proceeds to box 108 .

Box 108 checks to see if there is a pedaling event. If there is a tip-in event at box 108 , then at box 110 the hysteresis logic 78 checks whether the engine power command (P _tot ) 12 exceeds the previous quantized engine command (P _{tot_quantized_last} ) by a predetermined amount. This check can be done by comparing the engine power command (P _tot ) 12 with the sum of the previous quantized engine power command (P _{tot_quantized_last} ) and the upper limit (ie, P _tot > P _{tot_quantized_last} + upper limit) (block 110 ). The last quantized engine power command (P _{tot_quantized_last} ) is the value recorded by the quantizer 76 at the previous cycle "n-1". If the engine power command 12 exceeds the previous quantized engine power command by a predetermined amount, then, as shown in box 112, the quantized engine power command (P _{tot_quantized} ) 80 is set to the value generated in box 102 for the current cycle" Quantized engine power command (P _tot — quantized ) for n” (ie, P _tot — quantized = P _tot — quantized ). If the engine power command 12 exceeds the previous quantized engine power command by a value other than a predetermined amount, then as shown in block 114, the quantized engine power command (P _{tot_quantized} ) 80 is set to the previous quantized engine power command (P _{tot_quantized_last} ) (ie, P _{tot_quantized} = P _{tot_quantized_last} ).

If there is no pedal-in event (block 108 ), then there may be a tip-off event. Hysteresis logic 78 checks to see if the engine power command (P _tot ) 12 is less than the previous quantized engine power command (P _{tot_quantized_last} ) by a predetermined amount. This check can be done by comparing the engine power command (P _tot ) 12 with the difference between the previous quantized engine power command (P _{tot_quantized_last} ) and a lower limit (ie, P _tot < P _{tot_quantized_last} - lower limit) ( box 116). If the engine power command (P _tot ) 12 is less than the previous quantized engine power command (P _{tot_quantized_last} ) by a predetermined amount, then as shown in block 118, the output quantized engine power command (P _{tot_quantized} ) 80 is set to The quantized engine power command generated in block 102 for the current cycle "n" (ie, P _tot — quantized = P _tot — quantized ). If the engine power command (P _tot ) 12 is less than the previous quantized engine power command (P _{tot_quantized_last} ) by a value other than a predetermined amount, then as shown in block 120, the output quantized engine power command (P _{tot_quantized} ) 80 is set to the previous One quantized engine power command (P _{tot_quantized_last} ) (ie, P _{tot_quantized} = P _{tot_quantized_last} ).

The previous quantized engine power command (P _{tot_quantized_last} ) is then updated (block 122 ) to the output quantized engine power command (P _{tot_quantized} ) 80 determined in the current cycle (ie, P _{tot_quantized_last} = P _{tot_quantized} ). Furthermore, the updated engine power command of the previous quantization is used for the engine power command (P _tot ) 12 of the next cycle (ie n+1) at subsequent time points.

Referring now to FIG. 5 , with continued reference to the modified architecture 70 shown in FIG. 3 , there is shown a flowchart 130 describing a quantized engine power command filtering routine. Filter 82 of quantization and filtering module 72 performs this procedure.

First, the filter 82 accesses the output quantized engine power command (P _{tot_quantized} ) 80 and the previous quantized engine power command (P _{tot_quantized_last} ). As indicated above with reference to FIG. 3 , the filter 82 receives the power difference (ΔP) 84 between the engine power command (P _tot ) 12 and the quantized engine power command (P _{tot_quantized} ) 80 (i.e., ΔP=P _tot −P _{tot_quantized} ) as input. Filter 82 also receives as input a filter constant (Fk) 88 provided by filter determination calculation table 90 .

Operation of the quantized engine power command filter routine begins with filter 82 checking whether the quantized engine power command (P _{tot_quantized} ) 80 and the previous quantized engine power command (P _{tot_quantized_last} ) have a difference (i.e., P _{tot_quantized} ≠ P _{tot_quantized_last} , as shown in box 132). If there is a difference between the quantized engine power command (P _{tot_quantized} ) 80 and the previous quantized engine power command (P _{tot_quantized_last} ), the filter 82 resets the power difference (ΔP) 84 to zero and the filtered power difference (ΔP _filtered ) 86 is set to zero (ie, ΔP = 0 and ΔP _filtered = 0, as indicated by block 134 ). If the quantized engine power command (P _{tot_quantized} ) 80 and the previous quantized engine power command (P _{tot_quantized_last} ) have the same value, then in block 136 the filter 82 sets the power difference (ΔP) 84 to the engine power command (P _tot ) 12 and the output quantized engine power command (P _tot — quantized ) 80 (ie, ΔP=P _tot −P tot _{— quantized} ). In block 138 , filter 82 obtains filter constant (Fk) 88 . In box 140 , the power difference (ΔP) 84 obtained from box 136 as a function of the filter constant (Fk) 88 is filtered to produce a filtered power difference (ΔP _filtered ) 86 .

Once either block 134 or block 140 is complete, filter 84 outputs filtered power difference (ΔP _filtered ) 86 to summing node 94 of quantization and filtering module 72 . If output from box 134 , the filtered power difference (ΔP _filtered ) 86 is zero. If output from block 140 , the filtered power difference (ΔP _filtered ) 86 is the power difference (ΔP) 84 obtained from block 136 filtered as a function of a filter constant (Fk) 88 .

The routine from boxes 134 and 140 continues to box 142 which checks to see if the engine power command (P _tot ) 12 is greater than zero (ie, P _tot >0). If the engine power command (P _tot ) 12 is not greater than zero, then as shown in block 144, the engine power command (P _{tot_final} ) 74 output from the quantization and filtering module 72 is set to the engine power command (P _tot ) 12 (i.e. , P _{tot_final} = P _tot ). If the engine power command (P _tot ) 12 is greater than zero, then the output engine power command (P _{tot_final} ) 74 is set to the quantized engine power command (P _{tot_quantized} ) 80 and the filtered power difference (ΔP _filtered ) 86 (ie, P _tot — final = P _tot — quantized +ΔP _filtered ). In addition, the summing node 94 of the quantization and filtering module 72 sums the quantized engine power command (P _{tot_quantized} ) 80 and the filtered power difference (ΔP _filtered ) 86 and then outputs the engine power command (P _{tot_final} ) 74 (the above two sum of variables).

As shown in FIG. 3 , the quantization and filtering module 72 provides an engine power command (P _tot — final ) 74 to a vehicle system control (VCS) module 96 (eg, another portion of the controller 60 ). The VCS module 96 determines an optimal engine torque command for the engine 30 based on the engine power command (P _tot — final ) 74 . The quantization and filtering module 72 may also provide an engine power command (P _tot — final ) 74 to an engine operations management strategy (EOMS) module 98 (eg, another portion of the controller 60 ). The EOMS module 98 determines the engine speed command based on the engine power command (P _tot — final ) 74 .

The design principle of the filter determination calculation table 90 will now be explained in more detail. Faster filtering is applied when the power difference (ΔP) is smaller. This means that smaller changes in engine power command are somewhat permitted because they have less effect on triggering combustion transients. When the power differential (ΔP) is large, slower filtering is applied so that large command fluctuations and sudden changes are smoothed to a greater extent in open loop to reduce potential combustion inefficiencies. On the other hand, the higher the % fuel loss (Φ), the slower filtering is required to further suppress faster transients. Such a closed-loop mechanism ensures smooth engine power when large enrichment A/F errors are detected.

Note that when _{Ptot_quantized} ≠ _{Ptot_quantized_last} (indicating that there is indeed a desired engine power change from the driver), a reset can be applied to the power difference (ΔP) 84 and the filtered power difference (ΔP _filtered ) 86 ( FIG. 5 block 134). Thus, the output engine power command (P _tot — final ) 74 may be allowed to jump to a new point on the quantized power grid.

In summary, after quantization and filtering of the input engine power command (P _tot ) 12 , the final output profiled engine power command (P _{tot_final} ) 74 is determined as quantized engine power command (P _{tot_quantized} ) 80 and the sum of filtered power differences (ΔP _filtered ) 86 (ie, P _tot — final =P _tot — quantized +ΔP _filtered ).

Advantages provided by engine transient mitigation methods may include: smoothing engine operation and eliminating unwanted engine combustion transients in open loop to gently mitigate A/F enrichment; using the battery to absorb driver power "bumps" and Handles high-frequency and cluttered parts of driver dynamics; and adaptively optimizes engine power between "load leveling" and "load following" to further improve fuel economy.

The programs, methods or algorithms disclosed herein may be transferred to/implemented by a processing device, controller or computer, which may include any existing programmable electronic control unit or a dedicated electronic control unit. Similarly, the programs, methods or algorithms can be stored as data and instructions executable by a controller or computer in various forms, including but not limited to permanent storage in non-writable storage media (such as , ROM devices) and information variably stored on writable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The programs, methods or algorithms can also be implemented as software executable objects. Alternatively, the program, method, or algorithm may utilize suitable hardware components (such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), state machines, controllers, or other hardware components or devices) or hardware , a combination of software and firmware components are implemented in whole or in part.

While example embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As noted above, the features of various implementing embodiments may be combined to form further embodiments of the invention which may not be explicitly described or shown. While various embodiments have been described as providing advantages over other embodiments or prior art implementations in terms of one or more desirable characteristics, those of ordinary skill in the art will recognize that one or more Features or characteristics may be traded off to achieve desired overall system properties, which depend on the particular application and implementation. These attributes include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, ease of maintenance, weight, manufacturability, ease of assembly, etc. Accordingly, embodiments described as inferior to other embodiments or prior art implementations in one or more characteristics are not outside the scope of the present disclosure and may be desirable for particular applications.

Claims (6)

1. a vehicle, including:

Electromotor；

Traction battery；

At least one controller, be configured to ask electromotor with quantify motivation level operating, (i) when When Forecasting The Total Power Requirement is less than predetermined value, the motivation level of described quantization is at least equal to Forecasting The Total Power Requirement so that Traction battery receives power from electromotor, (ii) when Forecasting The Total Power Requirement more than another predetermined value time, described amount The motivation level changed is less than or equal to Forecasting The Total Power Requirement so that traction battery provides power to meet total output Demand, (iii) otherwise, the motivation level of described quantization is closest to the value of Forecasting The Total Power Requirement.

2. vehicle as claimed in claim 1, wherein, described traction battery is according to Forecasting The Total Power Requirement and amount Difference between the motivation level changed receives or provides power.

3. vehicle as claimed in claim 1, wherein, Forecasting The Total Power Requirement is driver demand for power and electricity The summation of pond power demand.

4. for a method for running engine, including:

When Forecasting The Total Power Requirement is less than predetermined value, export the power at least equal to Forecasting The Total Power Requirement from electromotor；

When Forecasting The Total Power Requirement is more than another predetermined value, it is less than the power of Forecasting The Total Power Requirement from electromotor output；

When Forecasting The Total Power Requirement is more than described predetermined value and is less than another predetermined value described, with multiple quantization water Equal that quantization level of the middle value closest to Forecasting The Total Power Requirement selected and ask moving from electromotor Power.

5. method as claimed in claim 4, wherein, described Forecasting The Total Power Requirement is driver demand for power Summation with battery power demand.

6. method as claimed in claim 4, described method also includes: when Forecasting The Total Power Requirement is less than described Predetermined value or during more than another predetermined value described, with the plurality of quantization level selects closest to total That quantization level of the value of power demand and ask the power from electromotor.