JP2012219760A - Vehicle control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control apparatus which can control torque variation when recovering from fuel cut.SOLUTION: A vehicle control apparatus includes: an engine which can variably control a compression ratio; and an electric motor which transmits motive force with the engine. While fuel cut is executed for stopping supply of a fuel to the engine during traveling of a vehicle, the compression ratio is set to a predetermined compression ratio at a lower compression side than a compression ratio corresponding to the load of the engine, and power generation by the electric motor is stopped. When resuming the supply of the fuel to the engine by recovering from the fuel cut (S21: Yes), the change of the compression ratio to a higher compression side is regulated (S22) and power generation is performed by the electric motor (S23).

Description

  The present invention relates to a vehicle control device.

  2. Description of the Related Art Conventionally, a technique for performing a fuel cut that stops the supply of fuel to an engine during traveling is known. For example, in Patent Document 1, when it is determined that the fuel cut condition is satisfied, the target compression ratio during the fuel cut is set to the low compression ratio tεFCUT, and the target compression ratio is converged to the low compression ratio tεFCUT to recover the fuel. A technology of a compression ratio control device for an internal combustion engine that allows the compression ratio to be controlled to a low compression ratio is disclosed. According to Patent Document 1, it is said that torque shock during fuel recovery is reduced.

JP 2004-239147 A

  Conventionally, sufficient studies have not been made on suppressing torque fluctuations when returning from a fuel cut. For example, it is preferable that the torque fluctuation when returning from the fuel cut can be suppressed by turning on the accelerator.

  The objective of this invention is providing the vehicle control apparatus which can suppress the torque fluctuation when returning from a fuel cut.

  A vehicle control device according to the present invention includes an engine capable of variably controlling a compression ratio, and a generator that transmits power to the engine, and a fuel cut that stops fuel supply to the engine while the vehicle is running. During execution, the compression ratio is set to a predetermined compression ratio that is lower than the compression ratio corresponding to the load of the engine, and the power generation by the generator is stopped, the fuel cut is resumed, and the fuel to the engine is reduced. When the supply is resumed, the change of the compression ratio to the high compression side is restricted, and the generator is caused to generate power.

  In the vehicle control device, it is preferable that a compression ratio of the engine after returning from the fuel cut and restarting fuel supply to the engine is maintained at the predetermined compression ratio.

  In the vehicle control device, when the fuel cut is being performed, the opening of the throttle valve of the engine is made larger than the opening based on the accelerator opening, and when the accelerator is turned on, the opening of the throttle valve is reduced. It is preferable to set the opening based on the accelerator opening.

  In the vehicle control device, when the opening degree of the throttle valve after the accelerator is turned on is smaller than the opening degree of the throttle valve before the accelerator is turned on, after the accelerator is turned on, It is preferable that the change of the compression ratio to the high compression side is restricted until the intake air amount is reduced to an amount corresponding to the opening degree of the throttle valve.

  In the vehicle control device, when the opening degree of the throttle valve after the accelerator is turned on is smaller than the opening degree of the throttle valve before the accelerator is turned on, after the accelerator is turned on, It is preferable to cause the generator to generate power until the intake air amount decreases to an amount corresponding to the opening of the throttle valve.

  In the vehicle control device, when the intake air amount of the engine decreases to an amount corresponding to the opening of the throttle valve, the compression ratio is changed to a high compression side to a compression ratio corresponding to the load of the engine, and It is preferable to perform control to increase the opening degree of the throttle valve while changing the compression ratio to the compression ratio corresponding to the engine load.

  Preferably, the vehicle control apparatus further includes a transmission, and the transmission is downshifted when returning from the fuel cut and restarting fuel supply to the engine.

  A vehicle control device according to the present invention includes an engine capable of variably controlling a compression ratio, and a generator that transmits power to the engine, and performs fuel cut to stop fuel supply to the engine while the vehicle is running. The compression ratio is set to a predetermined compression ratio that is lower than the compression ratio corresponding to the engine load, and power generation by the generator is stopped. Further, when the vehicle control device returns from the fuel cut and restarts the supply of fuel to the engine, the vehicle control device regulates the change of the compression ratio to the high compression side and causes the generator to generate power. Therefore, according to the vehicle control device of the present invention, it is possible to suppress the torque fluctuation when returning from the fuel cut.

FIG. 1 is a time chart relating to control by the vehicle control device of the embodiment. FIG. 2 is a schematic configuration diagram of the vehicle according to the embodiment. FIG. 3 is a diagram illustrating the engine of the vehicle according to the embodiment. FIG. 4 is a flowchart according to the operation of the accelerator ON return flag of the embodiment. FIG. 5 is a flowchart according to the determination of the large air amount time of the embodiment. FIG. 6 is a flowchart according to the accelerator-on return control of the embodiment. FIG. 7 is a diagram illustrating an example of a method of calculating the large air amount time. FIG. 8 is a time chart for explaining a shock that occurs when returning from a fuel cut.

  Hereinafter, a vehicle control device according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
The embodiment will be described with reference to FIGS. 1 to 7. The present embodiment relates to a vehicle control device. FIG. 1 is a time chart relating to control by the vehicle control device of the embodiment, FIG. 2 is a schematic configuration diagram of the vehicle according to the embodiment, FIG. 3 is a diagram illustrating an engine of the vehicle according to the embodiment, and FIG. FIG. 5 is a flowchart relating to the determination of the air amount large time according to the embodiment, FIG. 6 is a flowchart relating to the accelerator on return control according to the embodiment, and FIG. It is a figure which shows an example of the calculation method of large amount of time.

  The vehicle according to the present embodiment includes a variable compression ratio engine (see reference numeral 11 in FIG. 2) and a transmission (see reference numeral 15 in FIG. 2). The vehicle control device (see reference numeral 1-1 in FIG. 2) performs control to open the throttle when the accelerator is off to weaken the engine braking force and increase the fuel cut time. Here, when the control for opening the throttle is performed, there is a possibility that a shock may be generated due to a large torque when returning from the fuel cut when the accelerator is on, or the driver may feel uncomfortable.

  The vehicle control device 1-1 of the present embodiment sets the compression ratio ε of the engine 11 to low immediately after the accelerator is turned on during execution of fuel cut control, and turns on charging by the alternator (see reference numeral 21 in FIG. 2). At least one of setting or setting the gear ratio of the continuously variable transmission 15 to HI is performed. As a result, the increase or decrease of the drive shaft torque is suppressed when returning from the fuel cut. As a result, even if the intake air amount to the engine 11 becomes large at the time of return from the fuel cut, it is possible to suppress the occurrence of a shock or giving the driver an uncomfortable feeling.

  As shown in FIG. 2, vehicle 100 includes an engine 11, a torque converter 12, a continuously variable transmission 15, and an ECU 30. Further, the vehicle control device 1-1 of the present embodiment includes an engine 11, an alternator 21, and an ECU 30. Note that the vehicle control device 1-1 may further include a continuously variable transmission 15.

  The engine 11 is a power source of the vehicle 100. A torque converter 12 is connected to the rotating shaft of the engine 11. A drive shaft 13 of the torque converter 12 is connected to a continuously variable transmission 15 via a forward / reverse switching mechanism 14. The continuously variable transmission 15 is connected to drive wheels 19 via a propeller shaft 16, a differential gear 17 and a drive shaft 18.

  As shown in FIG. 3, the engine 11 has a cylinder 1. An intake pipe 2 and an exhaust pipe 3 are connected to the cylinder 1. A piston 4 is disposed in the cylinder 1. A combustion chamber 5 is formed closer to the intake pipe 2 and the exhaust pipe 3 than the piston 4 in the cylinder 1. An intake valve 6 is disposed at a connection portion between the combustion chamber 5 and the intake pipe 2, and an exhaust valve 7 is disposed at a connection portion between the combustion chamber 5 and the exhaust pipe 3. The intake pipe 2 has a surge tank 8. A throttle valve 9 is disposed upstream of the surge tank 8 in the intake pipe 2 in the direction of intake air flow.

  Returning to FIG. 2, when the engine 11 is driven, the power is output from the rotating shaft and is input from the torque converter 12 to the input shaft of the continuously variable transmission 15 via the forward / reverse switching mechanism 14. The power input to the continuously variable transmission 15 is decelerated at a gear ratio set in the continuously variable transmission 15 and output from the output shaft to the propeller shaft 16. The power input to the propeller shaft 16 is transmitted to the left and right drive shafts 18 via the differential gear 17 and can drive and rotate the left and right drive wheels 19.

  The engine 11 includes a variable compression ratio mechanism 20 that can change the compression ratio ε in the combustion chamber 5. The compression ratio variable mechanism 20 has an actuator, for example, an electric motor, that is operated by electromagnetic force or the like to change the compression ratio ε. The actuator of the compression ratio variable mechanism 20 changes the volume of the combustion chamber 5 by, for example, moving the cylinder block of the engine 11 relative to the crankcase in the axial direction of the cylinder 1, that is, the direction in which the piston 4 reciprocates. Change the compression ratio with. The method by which the compression ratio variable mechanism 20 changes the compression ratio is not limited to this. The compression ratio variable mechanism 20 may change the compression ratio, for example, by changing the closing timing of the intake valve 6 using an actuator. The compression ratio variable mechanism 20 can change the compression ratio ε of the engine 11 to an arbitrary compression ratio within a predetermined range.

  The engine 11 is provided with an alternator 21. The alternator 21 is a generator that transmits power to the engine 11. The alternator 21 is connected to the rotating shaft of the engine 11 via a belt, for example, and rotates in conjunction with the rotation of the engine 11. The alternator 21 generates electricity by being rotationally driven by power such as power output from the engine 11 or power transmitted from the drive wheels 19 via the engine 11. The alternator 21 can control the power generation amount. The alternator 21 is connected to a battery (not shown) and can charge the generated power to the battery.

  The continuously variable transmission 15 is an automatic transmission, and can change the gear ratio steplessly. The continuously variable transmission 15 is, for example, a belt type continuously variable transmission. The input side member (for example, primary pulley) and the output side member (for example, secondary pulley) of the continuously variable transmission 15 are connected via a belt. The continuously variable transmission 15 can transmit the driving force from the engine 11 from the input side member to the output side member via the belt, and continuously change the speed ratio which is the rotation speed ratio between the input side member and the output side member ( Continuously). The continuously variable transmission 15 is controlled by the hydraulic pressure supplied from the transmission hydraulic pressure control unit 28.

  The ECU 30 is an electronic control unit having a computer. The ECU 30 has a function of controlling the engine 11, the continuously variable transmission 15, the compression ratio variable mechanism 20, and the alternator 21. An accelerator position sensor 23, a throttle position sensor 24, an engine speed sensor 25, and a vehicle speed sensor 26 are connected to the ECU 30, and signals indicating the detection results of the sensors 23, 24, 25, and 26 are output to the ECU 30. . The accelerator position sensor 23 detects the amount of depression (accelerator opening) with respect to the accelerator pedal. The throttle position sensor 24 detects the throttle opening that is the opening of the throttle valve 9 in the electronic throttle device. The engine speed sensor 25 detects the speed of the engine 11. The vehicle speed sensor 26 detects the traveling speed of the vehicle 100.

  The ECU 30 controls the engine 11 based on the acquired detection results of the sensors. The ECU 30 can control the fuel injection amount by the injector of the engine 11, the fuel injection timing, the ignition timing by the spark plug, and the like, for example.

  Further, the ECU 30 can change the compression ratio ε of the engine 11 according to the driving state of the vehicle 100. For example, the ECU 30 variably controls the compression ratio according to the load of the engine 11. The load of the engine 11 is, for example, an intake air amount, an accelerator opening, a throttle opening, an engine speed, a fuel injection amount, and the like. For example, the ECU 30 may calculate the engine load based on the accelerator opening and the vehicle speed. In the present embodiment, the compression ratio ε of the engine 11 when the engine load is large is a compression ratio lower than the compression ratio ε when the engine load is small.

  The ECU 30 can execute the shift control by controlling the transmission hydraulic pressure control unit 28 to hydraulically control the continuously variable transmission 15. The ECU 30 is based on the driving state of the vehicle 100 (for example, vehicle speed, accelerator opening, brake pedal stroke, etc.) and a control map (for example, optimum fuel consumption curve based on engine speed, throttle opening, iso-output line, etc.). Thus, the gear ratio of the continuously variable transmission 15 is controlled so that the operating state of the engine 11 is optimized.

  Further, the ECU 30 can execute fuel cut control for stopping the supply of fuel to the engine 11 while the vehicle 100 is traveling. The ECU 30 executes fuel cut control when a predetermined fuel cut execution condition is satisfied. The fuel cut execution condition includes, for example, an accelerator-off state where the accelerator opening is equal to or less than a predetermined opening (for example, an opening 0), and the vehicle speed is equal to or higher than a predetermined vehicle speed.

  In the present embodiment, control for opening the throttle valve 9 is performed at the time of fuel cut. During execution of the fuel cut, the ECU 30 sets the opening of the throttle valve 9 to a larger opening than the throttle opening based on the accelerator opening and the throttle opening corresponding to the engine load. As a result, the pumping loss is suppressed and the engine braking force is reduced, so that the fuel cut duration can be extended.

  Further, the ECU 30 sets the compression ratio ε of the engine 11 to a predetermined compression ratio ε2 on the compression side lower than the compression ratio ε1 corresponding to the engine load during the fuel cut. The compression ratio ε of the engine 11 is lowered, the friction loss of the engine 11 is suppressed, and the engine braking force is reduced, so that the duration of fuel cut can be extended.

  Further, the ECU 30 turns off the power generation of the alternator 21 during the fuel cut. Thereby, the load by the alternator 21 is reduced and the friction loss of the engine 11 is reduced, so that the duration of fuel cut can be extended.

  The ECU 30 returns from the fuel cut and resumes the supply of fuel to the engine 11 when a predetermined fuel cut end condition is satisfied during the fuel cut. The fuel cut end condition can include, for example, an acceleration operation by a driver such as an accelerator on, a change in the running state of the vehicle 100 such as a decrease in engine speed or a decrease in vehicle speed. In the present embodiment, when the accelerator is turned on, the fuel cut is restored. Further, when the engine speed is equal to or lower than a predetermined fuel cut end rotational speed, the fuel cut is resumed.

  Here, if the control is performed to open the throttle valve 9 at the time of the fuel cut, a shock occurs when the fuel supply to the engine 11 is resumed after returning from the fuel cut, as will be described with reference to FIG. There are things to do. FIG. 8 is a time chart for explaining a shock that occurs when returning from a fuel cut.

  In FIG. 8, (a) is the accelerator opening, (b) is the throttle opening, (c) is the fuel cut (FC) execution flag, (d) is the engine torque, and (e) is the drive shaft torque. FIG. 8 shows the operation when the accelerator is turned on at time T11 during execution of fuel cut.

  The ECU 30 performs control to open the throttle valve 9 during execution of fuel cut before time T11. The control for opening the throttle valve 9 is, for example, control for setting the throttle opening to a predetermined opening θ1 that is larger than the opening based on the accelerator opening. The predetermined opening θ1 may be a constant value or variable depending on the traveling state or the like. When the accelerator is depressed and the accelerator is turned on at time T11, the ECU 30 changes the throttle opening to an opening θ2 based on the accelerator opening.

  Here, if control is performed to open the throttle valve 9 during fuel cut, the negative pressure in the intake pipe 2 is small, and a large amount of air is present between the intake valve 6 and the throttle valve 9 (see arrow Y1 in FIG. 3). Exists. When the accelerator is turned on from this state, a large amount of air between the intake valve 6 and the throttle valve 9 first flows into the cylinder. For this reason, a large torque is temporarily generated in the engine 11 and a drive shaft torque is increased, thereby generating a shock.

  Further, when the accelerator is turned on during fuel cut, the throttle valve 9 may move in the closing direction when the accelerator pedal is depressed shallowly. In FIG. 8, the throttle opening θ2 based on the accelerator opening after the accelerator is turned on is smaller than the predetermined opening θ1 that is the throttle opening before the accelerator is turned on. In this case, even though the throttle valve 9 is closed and the air amount is adjusted, a large amount of air between the intake valve 6 and the throttle valve 9 first flows into the cylinder. For this reason, a large torque is temporarily generated in the engine 11, and a shock is likely to occur due to an increase in the drive shaft torque, or the driver is likely to feel uncomfortable.

  When the vehicle control device 1-1 of the present embodiment returns from the fuel cut and restarts the fuel supply to the engine 11, the vehicle control device 1-1 regulates the change of the compression ratio ε of the engine 11 to the high compression side, and the alternator 21. To generate electricity. As a result, an increase in engine torque due to the high compression ratio ε is suppressed, and an increase in engine torque is suppressed by the load torque generated by the power generation of the alternator 21. Therefore, according to the vehicle control device 1-1 of the present embodiment, fluctuations in the drive shaft torque when returning from the fuel cut, for example, when returning from the fuel cut due to the accelerator being on, are suppressed, and shock and discomfort are suppressed. .

  Further, the vehicle control device 1-1 downshifts the continuously variable transmission 15 when returning from the fuel cut and restarting the fuel supply to the engine 11. As a result, an increase in drive shaft torque is suppressed, and a shock and a sense of incongruity are suppressed.

  With reference to FIG. 1 and FIGS. 4 to 7, the control by the vehicle control device 1-1 of the present embodiment will be described. In FIG. 1, (a) is an accelerator opening, (b) is a throttle opening, (c) is an engine speed, (d) is a fuel cut flag, (e) is a compression ratio ε, and (f) is an alternator 21. (G) is the engine torque, (h) is the gear ratio of the continuously variable transmission 15, (i) is the drive shaft torque, and (j) is the accelerator ON return flag. Moreover, in FIG. 1, a dashed-dotted line shows an example of transition of each value when control by the vehicle control apparatus 1-1 of this embodiment is not made, and a continuous line is by the vehicle control apparatus 1-1 of this embodiment. The transition of each value when control is performed is shown. Time T1 indicates the timing at which the accelerator is turned on.

  Each control flow of FIGS. 4 to 6 is executed while the vehicle 100 is traveling, and is repeatedly executed at predetermined intervals, for example. Each of these control flows may be executed in the order of figure numbers (FIG. 4 → FIG. 5 → FIG. 6), or may be executed in an order different from the order of figure numbers.

  In step S1 of FIG. 4, the ECU 30 reads the accelerator opening, the throttle opening, and whether or not fuel cut is performed. The ECU 30 can acquire the accelerator opening and the throttle opening based on the detection results of the accelerator position sensor 23 and the throttle position sensor 24. Moreover, ECU30 can acquire the presence or absence of fuel cut execution based on a fuel cut flag. The fuel cut flag is turned on when the fuel cut execution condition is satisfied. When step S1 is executed, the process proceeds to step S2.

  In step S2, the ECU 30 determines whether engine brake control is being executed. The engine brake control is a control for suppressing the engine braking force during fuel cut. In this embodiment, the control for opening the throttle valve 9, the control for turning off the power generation of the alternator 21, and the compression ratio ε of the engine 11 are predetermined. Control for setting the compression ratio ε2 is included in the engine brake control. For example, the ECU 30 performs an affirmative determination in step S2 when any of the controls included in the engine brake control is being executed, but when all the controls included in the engine brake control are being executed. You may make it perform affirmation determination. As a result of the determination in step S2, if it is determined that the engine brake control is being executed (step S2-Y), the process proceeds to step S3. If not (step S2-N), the process proceeds to step S4.

  In step S3, the engine brake control execution flag is turned ON by the ECU 30. When step S3 is executed, the control flow ends.

  In step S4, the engine brake control execution flag is turned OFF by the ECU 30. When step S4 is executed, the process proceeds to step S5.

  In step S5, the ECU 30 determines whether or not the previous engine brake control execution flag is ON. In step S5, it is determined whether or not the engine brake control execution flag has changed from ON to OFF. The previous engine brake control execution flag is, for example, the value of the engine brake control execution flag when the previous control flow ends and returns. As a result of the determination in step S5, if it is determined that the previous engine brake control execution flag is ON (step S5-Y), the process proceeds to step S6. If not (step S5-N), this control flow is performed. Ends.

  In step S6, the ECU 30 determines whether or not the accelerator is on. The ECU 30 can make the determination in step S6 based on the detection result of the accelerator position sensor 23. For example, the ECU 30 determines that the accelerator is on when the accelerator opening detected by the accelerator position sensor 23 is larger than a predetermined threshold. As a result of the determination in step S6, if it is determined that the accelerator is on (step S6-Y), the process proceeds to step S7, and if not (step S6-N), the control flow ends.

  In step S7, the ECU 30 determines whether or not the current throttle opening instruction value is smaller than the previous throttle opening. In step S7, it is determined whether or not the throttle opening after the accelerator is turned on is smaller than the throttle opening before the accelerator is turned on. The previous throttle opening is, for example, the throttle opening read in step S1 when the last control flow is executed. The ECU 30 performs the determination in step S7 based on the comparison result between the current throttle opening instruction value read in step S1 and the previous throttle opening. As a result of the determination in step S7, if it is determined that the current throttle opening instruction value is smaller than the previous throttle opening (step S7-Y), the process proceeds to step S8, otherwise (step S7-N). ) Ends the control flow.

  In step S8, the ECU 30 sets the accelerator ON return flag to ON. The accelerator ON return flag is ON when the accelerator is turned on and the throttle opening θ2 based on the accelerator opening after the accelerator is turned on is smaller than the predetermined opening θ1 that is the throttle opening before the accelerator is turned on. It is said.

  In the present embodiment, if the accelerator ON return flag is ON, accelerator ON return control is executed. The accelerator-on return control is a control that suppresses a torque shock or the like when returning from the fuel cut when the accelerator is turned on. The accelerator-on return control is a control for maintaining the compression ratio ε at a low compression ratio until the amount of air in the intake pipe 2 becomes in accordance with the opening of the throttle valve 9 when returning from the fuel cut (step S22 in FIG. 6). And control for generating power by the alternator 21 (see step S23 in FIG. 6). When step S8 is executed, the control flow ends.

  In step S11 of FIG. 5, the ECU 30 determines whether or not the previous accelerator ON return flag is OFF. The previous accelerator ON return flag is the value of the accelerator ON return flag when the previous control flow is executed. As a result of the determination in step S11, if it is determined that the previous accelerator ON return flag is OFF (step S11-Y), the process proceeds to step S12. If not (step S11-N), the process proceeds to step S15. .

  In step S12, the ECU 30 determines whether or not the current accelerator ON return flag is ON. In step S12, it is determined whether or not the accelerator ON return flag has been switched from OFF to ON. As a result of the determination in step S12, if it is determined that the current accelerator ON return flag is ON (step S12-Y), the process proceeds to step S13. If not (step S12-N), the control flow ends. To do.

  In step S13, the engine speed is read by the ECU 30. When step S13 is executed, the process proceeds to step S14.

  In step S14, the ECU 30 calculates a large air amount time. The large air amount time is a time during which the intake air amount to the combustion chamber 5 exceeds the intake air amount corresponding to the throttle opening. When the opening degree θ2 based on the accelerator opening degree when the accelerator is turned on is smaller than the predetermined opening degree θ1, a large amount of air remaining in the intake pipe 2 flows into the combustion chamber 5, Temporarily, the intake air amount to the combustion chamber 5 becomes larger than the intake air amount corresponding to the throttle opening. The large air amount time is a time required for the intake air amount to the combustion chamber 5 to converge (decrease) to the intake air amount corresponding to the throttle opening after the accelerator is turned on during the fuel cut. For example, the ECU 30 calculates the large air amount time based on the correspondence shown in FIG.

  In FIG. 7, the horizontal axis indicates the engine speed, and the vertical axis indicates the large amount of air. The large air amount time when the engine speed is small is calculated as a longer time than the large air amount time when the engine speed is large. The large air amount time may be determined so as to decrease linearly as the engine speed increases. The ECU 30 of the present embodiment refers to the correspondence relationship shown in FIG. 7 stored in advance, and calculates the large air amount time based on the engine speed read in step S13. When calculating the large air amount time, the ECU 30 starts counting by the timer whether or not the calculated large air amount time has elapsed. When step S14 is executed, this control flow ends.

  In step S15, the ECU 30 determines whether or not a large amount of air has elapsed. The ECU 30 determines whether or not the elapsed time counted by the timer has reached the large air amount time calculated in step S14. As a result of the determination in step S15, if it is determined that the large amount of air has elapsed (step S15-Y), the process proceeds to step S16. If not (step S15-N), the control flow ends. To do. In FIG. 1, it is determined that the large amount of air has elapsed at time T2.

  In step S16, the ECU 30 sets the accelerator ON return flag to OFF. When step S16 is executed, the control flow ends.

  In step S21 of FIG. 6, the ECU 30 determines whether or not the accelerator ON return flag is ON. As a result of the determination, if it is determined that the accelerator ON return flag is ON (step S21-Y), the process proceeds to step S22. If not (step S21-N), the process proceeds to step S25.

  In step S22, the compression ratio ε is lowered by the ECU 30. While the accelerator ON return flag is ON, in other words, the ECU 30 changes the compression ratio ε to the high compression side from when the accelerator is turned on until the intake amount of the engine 11 decreases to an amount corresponding to the throttle opening. To regulate. Here, restricting the change of the compression ratio ε toward the high compression side is, for example, setting the compression ratio ε to a compression ratio on the compression side lower than the compression ratio ε1 corresponding to the load of the engine 11. In the present embodiment, the ECU 30 sets the compression ratio ε while the accelerator ON return flag is ON to the predetermined compression ratio ε2. That is, the ECU 30 maintains the compression ratio ε of the engine 11 after returning from the fuel cut and restarting the fuel supply to the engine 11 at the predetermined compression ratio ε2.

  For example, the ECU 30 prohibits the change of the compression ratio ε to the high compression side while the accelerator ON return flag is ON, and maintains the compression ratio when the accelerator ON return flag is ON. May be. Alternatively, the ECU 30 may change the compression ratio ε to the lower compression side than when the accelerator ON return flag is ON while the accelerator ON return flag is ON. Further, regulating the change of the compression ratio ε toward the high compression side includes suppressing the rate of change of the compression ratio ε toward the high compression side.

  Note that the target value of the compression ratio ε while the accelerator ON return flag is ON may be determined based on, for example, the amount of air in the intake pipe 2 or the amount of intake air with respect to the combustion chamber 5. As an example, the target compression ratio ε may be changed to a value on the high compression side in accordance with a decrease in the amount of air in the intake pipe 2. By restricting the change of the compression ratio ε to the high compression side, the combustion efficiency of the engine 11 is reduced, and an increase in engine torque is suppressed. When step S22 is executed, the process proceeds to step S23.

  In step S23, charging by the alternator 21 is turned on by the ECU 30. That is, the ECU 30 causes the alternator 21 to generate power while the accelerator ON return flag is ON, that is, after the accelerator is turned on, until the intake air amount of the engine 11 decreases to an amount corresponding to the throttle opening.

  The ECU 30 causes the alternator 21 to generate power and charges the battery. The alternator 21 is preferably turned on immediately after the accelerator is turned on. When the alternator 21 generates power and generates load torque, a rapid increase in engine torque is suppressed. If the generation timing of the load torque due to the start of power generation by the alternator 21 is matched to the rise of the engine torque due to the start of combustion in the engine 11, the rapid increase of the engine torque is more reliably suppressed. be able to. The alternator 21 can generate a torque that cancels the increase in engine torque with high response.

  The power generation amount of the alternator 21 while the accelerator ON return flag is ON may be determined based on, for example, the amount of air in the intake pipe 2 or the amount of intake air to the combustion chamber 5. As an example, the target power generation amount may be decreased in accordance with a decrease in the amount of air in the intake pipe 2. When step S23 is executed, the process proceeds to step S24.

  In step S24, the gear ratio of the continuously variable transmission 15 is set to HI by the ECU 30. The ECU 30 downshifts the continuously variable transmission 15 to a speed ratio larger than the speed ratio before the accelerator is turned on, that is, a speed ratio on the low speed side. The ECU 30 determines that the speed ratio of the continuously variable transmission 15 is accelerator-on while the accelerator ON return flag is ON, that is, after the accelerator is turned on until the intake air amount of the engine 11 decreases to an amount corresponding to the throttle opening. HI than the previous gear ratio.

  In this downshift, the ECU 30 downshifts the continuously variable transmission 15 regardless of the gear ratio based on the control map, for example. The downshift of the continuously variable transmission 15 is preferably performed immediately after the accelerator is turned on. By setting the gear ratio of the continuously variable transmission 15 to HI, an increase in the drive shaft torque is suppressed, and the occurrence of a shock and a feeling of discomfort to the driver are suppressed. For example, the downshift destination gear ratio may be determined based on an operating point at which the efficiency of the engine 11 is low. When step S24 is executed, this control flow ends.

  In step S25, the ECU 30 returns to the conventional control. Here, the conventional control in step S25 is the control in which the compression ratio ε of the engine 11 is set to the compression ratio ε1 corresponding to the load, the alternator 21 is controlled regardless of the accelerator ON return flag, and the continuously variable transmission 15 is controlled. This includes control regardless of the accelerator ON return flag. That is, when the air amount large time elapses and the intake amount of the engine 11 decreases to an amount corresponding to the throttle opening, the ECU 30 increases the compression ratio ε to the compression ratio ε1 corresponding to the load of the engine 11. Change.

  In FIG. 1, it is determined that the large amount of air has elapsed at time T2, and the compression ratio ε starts to change toward the compression ratio ε1 corresponding to the load. Further, at time T2, the power generation of the alternator 21 is turned off, for example, and acceleration performance is ensured. Further, at time T2, continuously variable transmission 15 is upshifted to a gear ratio based on the control map. When step S25 is executed, the process proceeds to step S26.

  In step S26, the ECU 30 corrects the throttle to the open side. A predetermined time is required to change the compression ratio ε from the predetermined compression ratio ε2 to the compression ratio ε1 corresponding to the load. During this time, since the actual compression ratio ε (solid line in FIG. 1) is a value on the lower compression side than the compression ratio ε1 corresponding to the load, the torque may drop. For example, immediately after time T2 when the large amount of air has elapsed, the difference between the target compression ratio ε1 and the actual compression ratio ε is large, and a torque drop tends to occur.

  On the other hand, the ECU 30 sets the throttle opening to an opening larger than the opening θ2 based on the accelerator opening until time T3 when the compression ratio ε reaches the target compression ratio ε1. In other words, the ECU 30 performs control to increase the throttle opening while changing the compression ratio ε to the compression ratio ε1 corresponding to the load. The correction amount of the throttle opening can be determined based on the magnitude of the difference between the compression ratio ε1 corresponding to the load and the actual compression ratio ε, for example. When step S26 is executed, the control flow ends.

  As described above, according to the vehicle control device 1-1 of the present embodiment, when returning from the fuel cut and restarting the fuel supply to the engine 11, the compression ratio ε of the engine 11 changes to the high compression side. Power generation by the alternator 21 is performed. Therefore, according to the vehicle control device 1-1 of the present embodiment, it is possible to suppress the torque fluctuation when returning from the fuel cut, thereby suppressing the occurrence of a shock and a sense of discomfort.

  In the present embodiment, the generator that generates power when returning from the fuel cut is the alternator 21, but is not limited thereto. Instead of the alternator 21 or in addition to the alternator 21, power generation at the time of return may be performed by a motor generator or the like that transmits power to the engine 11.

  The vehicle control device 1-1 according to the present embodiment stops the power generation by the alternator 21 during execution of the fuel cut, and causes the alternator 21 to generate power when returning from the fuel cut due to the accelerator being turned on. The amount of power generated by the alternator 21 may be reduced during the fuel cut, and the amount of power generated by the alternator 21 may be increased when returning from the fuel cut due to the accelerator being turned on.

  Instead of increasing or decreasing the engine auxiliary load by power generation by the alternator 21, an increase in engine torque may be suppressed by increasing or decreasing the engine auxiliary load by an air conditioner, a power steering device or the like.

  Instead of the continuously variable transmission 15, an increase in drive shaft torque may be suppressed by downshifting the stepped transmission.

  The contents disclosed in the above embodiments can be executed in appropriate combination.

1-1 Vehicle control device 11 Engine 15 Continuously variable transmission (CVT)
20 Variable compression ratio mechanism 21 Alternator 30 ECU
100 Vehicle θ1 Predetermined opening θ2 Opening based on accelerator opening ε1 Compression ratio according to load ε2 Predetermined compression ratio

Claims (7)

An engine capable of variably controlling the compression ratio;
A generator for transmitting power to the engine;
With
During the fuel cut for stopping the fuel supply to the engine while the vehicle is running, the compression ratio is set to a predetermined compression ratio lower than the compression ratio corresponding to the load of the engine, and the generator Stop power generation,
When returning from the fuel cut and restarting the supply of fuel to the engine, a change in the compression ratio to a high compression side is restricted, and the vehicle generator is configured to generate power. . The vehicle control device according to claim 1, wherein a compression ratio of the engine after returning from the fuel cut and restarting fuel supply to the engine is maintained at the predetermined compression ratio. While the fuel cut is being performed, the throttle valve opening of the engine is set to an opening larger than the opening based on the accelerator opening, and when the accelerator is turned on, the throttle valve opening is opened based on the accelerator opening. The vehicle control device according to claim 1 or 2. When the opening degree of the throttle valve after the accelerator is on is smaller than the opening degree of the throttle valve before the accelerator is turned on, the intake air amount of the engine becomes the throttle valve after the accelerator is turned on. The vehicle control device according to claim 3, wherein a change to the high compression side of the compression ratio is restricted until the amount decreases to an amount corresponding to the opening degree of the vehicle. When the opening degree of the throttle valve after the accelerator is on is smaller than the opening degree of the throttle valve before the accelerator is turned on, the intake air amount of the engine becomes the throttle valve after the accelerator is turned on. The vehicle control device according to claim 3, wherein the generator is configured to generate electric power until the amount decreases to an amount corresponding to an opening of the vehicle. When the intake air amount of the engine decreases to an amount corresponding to the opening of the throttle valve, the compression ratio is changed to a high compression side to a compression ratio corresponding to the load of the engine, and the compression ratio is changed to that of the engine. The vehicle control device according to claim 4, wherein control is performed to increase the opening degree of the throttle valve while changing to a compression ratio corresponding to a load. Furthermore, a transmission is provided,
The vehicle control device according to any one of claims 1 to 6, wherein the transmission is downshifted when returning from the fuel cut and restarting fuel supply to the engine.

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