Hybrid electric vehicle control device

Abstract

To provide a control device of a hybrid electric vehicle configured to suppress NOx purification capability of an exhaust gas purifying catalyst from decreasing while suppressing a battery from deteriorating when stopping an engine.SOLUTION: A control device of a hybrid electric vehicle is applied to a hybrid electric vehicle which is provided with an internal combustion engine including a fuel jet device and a throttle valve arranged on an air-intake passage and a power generator that can generate electric power by power of the internal combustion engine. The control device executes fuel cutoff for stopping supply of fuel from the fuel jet device and full-open control of bringing the throttle valve into a full-open state, when stopping the internal combustion engine; and executes full-close control of bringing the throttle valve into a full-close state and application control of applying power-generation loads by the power generator to the internal combustion engine, after an exhaust air-fuel ratio is made into a lean state, in a course of stopping an engine after executing the full-open control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a control system for a hybrid electric vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle control device that includes a direct injection engine and a rotating electric machine connected to the engine, and when a request to stop the engine is made, the vehicle control device opens the throttle while maintaining the engine speed using the rotating electric machine, and then stops the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 061454 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the control described in Patent Document 1, the time required for the engine shutdown process, from when fuel supply is stopped in response to a request to stop the internal combustion engine until the internal combustion engine is completely stopped, becomes longer. As a result, the exhaust purification catalyst is exposed to fresh air (i.e., gas with a high oxygen concentration) for a longer period during the engine shutdown process, which may result in a decrease in the NOx purification ability of the exhaust purification catalyst. In this regard, in a hybrid electric vehicle (HEV) equipped with a generator connected to the internal combustion engine, the power generation load generated by the generator can be used to quickly reduce the engine speed when the engine is stopped. However, if the internal combustion engine in an HEV is stopped and restarted frequently, the number of times the generator generates electricity increases, which results in repeated charging of the battery, which may cause battery deterioration.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a control device for a hybrid electric vehicle that can suppress battery degradation while suppressing a decrease in the NOx purification capacity of an exhaust purification catalyst when the engine is stopped. [Means for solving the problem]

[0006] A control device for a hybrid electric vehicle according to the present disclosure is applied to a hybrid electric vehicle equipped with an internal combustion engine including a fuel injection device and a throttle valve disposed in an intake passage, and a generator capable of generating electricity using the power of the internal combustion engine. When stopping the internal combustion engine, the control device executes a fuel cut to stop the supply of fuel from the fuel injection device and a full-open control to fully open the throttle valve, and during the engine stopping process after executing the full-open control, executes a full-close control to fully close the throttle valve after the exhaust air-fuel ratio becomes lean, and an application control to apply a power generation load of the generator to the internal combustion engine. [Effects of the Invention]

[0007] According to the control device for a hybrid electric vehicle of the present disclosure, the full-open control, the full-close control, and the application control are executed as described above, so that it is possible to suppress a decrease in the NOx purification capacity of the exhaust purification catalyst while suppressing battery degradation when the engine is stopped. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically illustrating an example of the configuration of a hybrid electric vehicle according to a first embodiment. [Figure 2] 4 is a time chart for explaining an overview of control when the engine is stopped according to the first embodiment. [Figure 3] 5 is a flowchart showing an example of a flow of processing related to control when the engine is stopped according to the first embodiment. [Figure 4] 10 is a flowchart showing an example of a flow of processing related to control when the engine is stopped according to the second embodiment. [Figure 5]11 is a flowchart showing an example of a flow of processing related to control when the engine is stopped according to the third embodiment. [Figure 6] FIG. 10 is a diagram illustrating another example configuration of a hybrid electric vehicle to which the control at engine stop according to the present disclosure can be applied. [Figure 7] 10 is a flowchart showing another example of the flow of processing related to control when the engine is stopped according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that elements common to the drawings will be assigned the same reference numerals, and redundant explanations will be omitted or simplified.

[0010] 1. First Embodiment 1-1. Example of Hybrid Electric Vehicle (HEV) Configuration 1 is a diagram schematically illustrating an example of the configuration of a hybrid electric vehicle 1 according to embodiment 1. The hybrid electric vehicle (hereinafter also simply referred to as "vehicle") 1 includes a power train 10 that constitutes, as an example, a power split (series-parallel) hybrid system.

[0011] The powertrain 10 includes an internal combustion engine 12 and two electric motors 14 and 16 as driving power sources, as well as a power split device 18, a reduction gear 20, and a drive shaft 22.

[0012] The internal combustion engine 12 is, for example, a spark ignition engine, and includes a fuel injector 24 and a throttle valve 26. The fuel injector 24 supplies fuel to each cylinder. The throttle valve 26 is disposed in an intake passage and is an actuator for controlling the amount of intake air into the internal combustion engine 12. An exhaust purification catalyst 27 having a NOx purification capability is disposed in an exhaust passage of the internal combustion engine 12. The exhaust purification catalyst 27 is, for example, a three-way catalyst having an oxygen storage capability, and hereinafter may also be simply referred to as "catalyst 27."

[0013] The electric motors 14 and 16 each also function as a generator. More specifically, the electric motor 14 functions primarily as a generator, and the electric motor 16 functions primarily as an electric motor. For this reason, the electric motor 14 will also be referred to as a "generator 14" hereinafter. The electric motors 14 and 16 are, for example, AC synchronous motors. The electric motor 14 and the internal combustion engine 12 are connected to each other by a power split mechanism 18. The power split mechanism 18 and the electric motor 16 are connected to each other via a reduction gear 20. The reduction gear 20 includes a differential gear and is connected to the wheels 2 via a drive shaft 22. The power split mechanism 18 distributes the power of the internal combustion engine 12 to the electric motor (generator) 14 and the reduction gear 20. The reduction gear 20 reduces the speed of the power of the internal combustion engine 12 and the power of the electric motor 16 transmitted via the power split mechanism 18, and transmits the power to the wheels 2 via the drive shaft 22.

[0014] The vehicle 1 also includes a battery 28 and a power control unit (PCU) 30. The battery 28 exchanges power with the powertrain 10 (more specifically, with each of the electric motors 14 and 16) via the PCU 30. The PCU 30 includes an inverter, which converts the power stored in the battery 28 from direct current to alternating current and supplies the converted power to the electric motor 16. As a result, the electric motor 16 is driven. The electric motor 14 can generate power by being driven by the power of the internal combustion engine 12. The electric motor 16 can generate power by being driven by the rotation of the wheels 2 during vehicle deceleration (regenerative braking). The power generated by the electric motor 14 or the electric motor 16 is converted from alternating current to direct current by the PCU 30 and then stored in the battery 28. In this way, the battery 28 is charged by the power generated by the electric motors 14 and 16 and discharged by the power consumed by the electric motor 16.

[0015] The vehicle 1 also includes a brake actuator 32. The brake actuator 32 controls the brake hydraulic pressure supplied to the brake mechanism of each wheel 2, thereby enabling friction braking torque Tb of each wheel 2 to be controlled independently.

[0016] Furthermore, the vehicle 1 is equipped with an electronic control unit (ECU) 40, which corresponds to a "control device" that controls the vehicle 1. The ECU 40 is equipped with a processor and a storage device. The ECU 40 receives sensor signals from sensors 34 attached to the vehicle 1 and outputs operation signals to the powertrain 10 (internal combustion engine 12, electric motors 14 and 16), the PCU 30, and the brake actuator 32. The storage device stores control programs for various controls of the vehicle 1 by the ECU 40. The processor reads and executes the control programs from the storage device. This allows various controls by the ECU 40 to be realized. Note that the functions of the ECU 40 may be realized by multiple ECUs.

[0017] The sensors 34 include various sensors used for various controls of the vehicle 1, such as a crank angle sensor, an air-fuel ratio sensor, an accelerator position (accelerator opening) sensor, and a brake position sensor. In addition, the crank angle sensor detects the crank angle of the internal combustion engine 12. The ECU 40 calculates the engine speed based on the output signal of the crank angle sensor. The air-fuel ratio sensor is disposed at least either upstream or downstream of the catalyst 27, and detects the exhaust air-fuel ratio.

[0018] The vehicle 1 also includes an air conditioner (air conditioner) 36 for conditioning the interior of the vehicle, and an audio device 38 provided in the vehicle.

[0019] 1-2.Control when engine is stopped In order to suppress deterioration of the battery 28 while suppressing a decrease in the NOx purification capability when the engine is stopped, in this embodiment, the ECU 40 executes the following control when stopping the internal combustion engine 12. That is, the ECU 40 executes a "fuel cut" that stops the supply of fuel from the fuel injector 24, and a "full-open control" that fully opens the throttle valve 26. Then, during the engine stopping process after the execution of the full-open control, the ECU 40 executes a "full-close control" that fully closes the throttle valve after the exhaust air-fuel ratio becomes lean, and an "application control" that applies the power generation load of the generator 14 to the internal combustion engine 12.

[0020] 2 is a time chart for explaining an outline of control when the engine is stopped (more specifically, during the engine stopping process (t1 to t3)) according to embodiment 1. Time t1 in Fig. 2 corresponds to the time when a stop condition for the internal combustion engine 12 is met while the vehicle 1 is traveling.

[0021] At time t1, the ECU 40 starts a fuel cut and executes (starts) full-open control of the throttle valve 26. As a result, with the start of the fuel cut, the engine speed decreases, and air (fresh air) with a high oxygen concentration is introduced into the exhaust passage, causing the exhaust air-fuel ratio to become leaner, for example, from the stoichiometric air-fuel ratio. In the example shown in Fig. 2, the throttle valve 26 is controlled to a fully open state by the full-open control, so the exhaust air-fuel ratio becomes leaner more quickly than in an example without the full-open control.

[0022] Time t2, which follows time t1, corresponds to the time when the exhaust air-fuel ratio (more specifically, the exhaust air-fuel ratio at the position of the catalyst 27) becomes lean to a predetermined lean air-fuel ratio (predetermined lean state). At time t2, the ECU 40 switches the control of the throttle valve 26 from "full-open control" to "full-close control" and executes (starts) "applying control." FIG. 2 shows "engine rotation reducing torque" which corresponds to the power generation load torque in the applying control. This reducing torque is a negative torque generated by the generator 14 to hinder engine rotation.

[0023] By applying the reduction torque, the rate at which the engine speed decreases after time t2 increases compared to the period before time t2, as shown in Fig. 2. In this embodiment, the throttle valve 26 is fully closed simultaneously with the application of the reduction torque. As a result, the engine braking force Feb, which increases due to an increase in the pumping loss of the internal combustion engine 12, prevents the engine speed from being maintained, and thus the rate at which the engine speed decreases increases.

[0024] Time t3 following time t2 corresponds to the time when the engine speed drops to zero, that is, the time when the internal combustion engine 12 completely stops. When time t3 arrives, the full-closure control and the application control are terminated.

[0025] 3 is a flowchart showing an example of a flow of processing related to control when the engine is stopped according to Embodiment 1. The processing of this flowchart is repeatedly executed while the vehicle 1 is traveling.

[0026] In step S100, the ECU 40 (control device) determines whether or not a predetermined engine stop condition is met for the internal combustion engine 12. This determination can be made based on information such as the accelerator opening detected by an accelerator position sensor and the state of charge (SOC) of the battery 28.

[0027] As a result, if the engine stop condition is met, the ECU 40 controls the fuel injector 24 to perform fuel cut in step S102. Next, in step S104, the ECU 40 performs full-open control of the throttle valve 26. More specifically, the throttle valve 26 may be fully opened at the maximum operating speed of the actuator of the throttle valve 26, for example.

[0028] Next, in step S106, the ECU 40 determines whether the exhaust air-fuel ratio has become lean to a predetermined lean state. This determination can be made, for example, based on whether the exhaust air-fuel ratio detected by the above-mentioned air-fuel ratio sensor has become equal to or greater than a predetermined lean threshold. More specifically, the lean threshold is determined in advance as the value of the exhaust air-fuel ratio at which application of torque reduction by application control begins. The determination in step S106 may also be made, for example, as follows. That is, the time required for the exhaust air-fuel ratio to become lean from the start of fuel cut may be obtained in advance by experiment or the like, and the determination may be made based on whether the time has elapsed since the start of fuel cut.

[0029] As long as the determination result in step S106 is No (i.e., the exhaust air-fuel ratio has not reached a lean state), the ECU 40 continues to fully open the throttle valve 26. On the other hand, if the determination result is Yes, the ECU 40 executes fully closing control of the throttle valve 26 and control of applying a power generation load in step S108. That is, the fully opening control is ended, and the opening degree of the throttle valve 26 is changed from the fully open state to the fully closed state. Furthermore, the power generation load of the generator 14 is applied to the internal combustion engine 12 by the control of the PCU 30 by the ECU 40. More specifically, the opening degree of the throttle valve 26 in the fully closed state (fully closed opening degree) is smaller than the idle opening degree used during idle operation.

[0030] Next, in step S110, the ECU 40 determines whether the internal combustion engine 12 has completely stopped, for example, using the crank angle sensor described above. As a result, if the result of this determination is No (i.e., if the internal combustion engine 12 has not completely stopped), the ECU 40 continues the full-close control and the application control. On the other hand, if the result of this determination is Yes, the ECU 40 ends the processing of this flowchart. This ends the full-close control and the application control.

[0031] 1-3.Effects As described above, according to this embodiment, when the engine stop condition is met while the vehicle 1 is running, first, fuel is cut and the throttle valve is fully opened. Then, during the engine stop process after the full-open control is executed, after the exhaust air-fuel ratio becomes lean, the power generation load is applied to the internal combustion engine 12 by the application control while the throttle valve 26 is fully closed. This provides the following effects.

[0032] (1) Since the application of the power generation load for quickly stopping the internal combustion engine 12 is performed after the exhaust air-fuel ratio becomes lean, compared to an example in which the power generation load is applied throughout the engine stopping process, the power generation load can be suppressed while preventing the lean state, in which the NOx purification ability of the catalyst 27 decreases, from becoming prolonged during the engine stopping process. Reducing the power generation load helps to suppress deterioration of the battery 28 due to overcharging of the battery 28. (2) Furthermore, according to this embodiment, the intake air amount is increased by full-throttle control executed when a fuel cut is initiated, thereby quickly making the exhaust air-fuel ratio leaner. More specifically, since the exhaust air-fuel ratio can be made leaner while shortening the time that the catalyst 27 is exposed to fresh air, the exhaust air-fuel ratio can be made leaner while suppressing a decrease in NOx purification capability, compared to an example in which the catalyst 27 is exposed to fresh air for a long time during the engine stop process. This makes it possible to suppress NOx emissions after the engine is subsequently restarted. (3) According to this embodiment, after the exhaust air-fuel ratio becomes lean, the power generation load is applied with full closure control. This reduces the time required to completely stop the internal combustion engine 12 compared to an example in which only the power generation load is applied without full closure control, which also makes it possible to reduce the power generation load. Furthermore, the application of the power generation load with full closure control reduces the time required to completely stop the internal combustion engine 12, which also helps prevent a decrease in the NOx purification capacity.

[0033] As described above, according to this embodiment, it is possible to suppress the deterioration of the battery 28 when the engine is stopped, while suppressing the decrease in the NOx purification capacity of the exhaust purification catalyst 27 (reducing the amount of NOx emissions).

[0034] 2. Second Embodiment The control when the engine is stopped according to the second embodiment differs from the control according to the first embodiment in the following respects: Fig. 4 is a flowchart showing an example of the flow of processing related to the control when the engine is stopped according to the second embodiment.

[0035] In FIG. 4, after the ECU 40 executes a fuel cut (step S102) in response to the establishment of the engine stop condition (step S100; Yes), it determines in step S200 whether the air conditioner 36 and the audio equipment 38 are both in the OFF state.

[0036] As a result, if the determination result in step S200 is No (if at least one of the air conditioner 36 and the audio device 38 is ON), the process proceeds to step S202, and the processes of steps S104 to S110 described above are executed in the procedure shown in Fig. 3. That is, in this case, the above-mentioned full-open control, full-close control, and application control are executed.

[0037] On the other hand, if the determination result in step S200 is Yes (the air conditioner 36 is OFF and the audio device 38 is OFF), the process proceeds to step S204, and the processes in steps S106 to S110 described above are executed in the procedure shown in FIG. 3. That is, in this case, the above-mentioned full-open control is not executed.

[0038] If the throttle valve 26 is suddenly fully opened by the above-described full-open control, there is a possibility that vibration noise will be generated due to an increase in the flow rate of air entering and exiting each cylinder of the internal combustion engine 12. In consideration of this phenomenon, according to the second embodiment described above, the full-open control is not executed when the background noise inside the vehicle 1 is low because both the air conditioner 36 and the audio device 38 are in the OFF state. This makes it possible to suppress a deterioration in the vibration noise performance of the vehicle 1 in a situation where the vibration noise is easily heard by a user inside the vehicle 1 due to the low background noise inside the vehicle 1.

[0039] In addition, when both the air conditioner 36 and the audio equipment 38 are OFF, the background noise is lower than when only one of the air conditioner 36 and the audio equipment 38 is OFF, so refraining from executing the full-open control as in the second embodiment is more effective in suppressing a deterioration in the vibration and noise performance of the vehicle 1. However, the control when the engine is stopped according to the second embodiment is not necessarily limited to when both the air conditioner 36 and the audio equipment 38 are OFF, and the full-open control may also be configured not to be executed when only one of them is OFF.

[0040] Furthermore, when at least one of the air conditioner 36 and the audio equipment 38 is in the OFF state, the control may be configured so that neither the full-open control nor the full-close control is executed when the engine is stopped.

[0041] 3. Embodiment 3 The control during engine stop according to the third embodiment differs from the control according to the first embodiment described above in that the following "acceleration change suppression control" is additionally executed. Specifically, when the throttle valve 26 is brought into a fully closed state by the full closure control, the engine braking force Feb generated during the engine stop process becomes larger than when the full closure control is not executed during the engine stop process (for example, when an idle opening is used), and a change in the vehicle acceleration G occurs. The acceleration change suppression control controls the vehicle 1 so as to suppress a change in the vehicle acceleration G that accompanies the execution of the full closure control. Note that the third embodiment may be executed in combination with the second embodiment.

[0042] Fig. 5 is a flowchart showing an example of the flow of processing related to control when the engine is stopped according to the third embodiment. Compared to Fig. 3, in Fig. 5, instead of the processing of step S108, in step S300, the ECU 40 executes full closure control of the throttle valve 26 accompanied by acceleration change suppression control and power generation load application control. This acceleration change suppression control in step 300 is targeted at the vehicle 1 having the configuration shown in Fig. 1 that does not have a clutch mechanism between the internal combustion engine 12 and the wheels 2. The acceleration change suppression control, together with the full closure control and application control, is executed until the internal combustion engine 12 completely stops (step S110; Yes).

[0043] Specifically, when the engine stop condition is met while the vehicle 1 is accelerating or running steadily (at a constant speed), the ECU 40 executes the acceleration change suppression control as follows: That is, the ECU 40 controls the electric motor 16 to increase the vehicle driving force Fvd to offset a decrease ΔFvd in the vehicle driving force Fvd that corresponds to an increase in the engine braking force Feb accompanying the execution of the full-close control.

[0044] More specifically, the increase ΔFeb in the engine braking force Feb, i.e., the increase ΔFeb associated with switching the throttle valve 26 from a fully open state to a fully closed state, can be obtained in advance, for example, through experiments or the like, in association with a parameter P such as the engine speed. Then, an increase ΔTmd in the drive torque Tmd of the electric motor 16 required to offset the decrease ΔFvd in the vehicle drive force Fvd corresponding to the increase ΔFeb obtained in this way is obtained in advance in association with the parameter P and stored in a storage device of the ECU 40, for example, as a map. The ECU 40 controls the electric motor 16 so as to generate the increase ΔTmd obtained from the map during the engine stop process.

[0045] Furthermore, when the engine stop condition is satisfied during deceleration of the vehicle 1, the ECU 40 executes the acceleration change suppression control as follows: That is, the ECU 40 reduces the vehicle braking force Fvb to offset the increase ΔFvb in the vehicle braking force Fvb that corresponds to the increase in the engine braking force Feb accompanying the execution of the full closure control.

[0046] More specifically, when regenerative braking is performed using the electric motor 16 functioning as a generator, the reduction in the vehicle braking force Fvb is achieved by reducing the regenerative braking torque Tmb generated by the electric motor 16 by a reduction ΔTmb required to offset the increase ΔFvb in the vehicle braking force Fvb corresponding to the increase ΔFeb. This reduction ΔTmb is obtained, for example, based on the same concept as the increase ΔTmd in the drive torque Tmd, and is stored, for example, as a map in the storage device of the ECU 40. The ECU 40 controls the electric motor 16 to generate the reduction ΔTmb obtained from the map during the engine stop process.

[0047] Furthermore, when friction braking is performed using the braking device of the vehicle 1, the reduction in the vehicle braking force Fvb may be achieved by reducing the friction braking torque Tb controlled by the brake actuator 32 by a reduction ΔTb required to offset the increase ΔFvb in the vehicle braking force Fvb corresponding to the increase ΔFeb. This reduction ΔTb is also obtained, for example, based on the same concept as the increase ΔTmd in the drive torque Tmd, and is stored, for example, as a map in the storage device of the ECU 40. The ECU 40 controls the brake actuator 32 so as to generate the reduction ΔTb obtained from the map during the engine stop process.

[0048] In addition, in the above-mentioned acceleration change suppression control, the wheel whose driving torque Tmd or regenerative braking torque Tmb is controlled by the electric motor 16 and the wheel whose friction braking torque Tb is controlled by the brake actuator 32 may be the same or different.

[0049] According to the acceleration change suppression control shown in FIG. 6 described above, it is possible to avoid or suppress changes in vehicle acceleration G that may occur during the engine stop process due to the execution of the full closure control.

[0050] (Another example of acceleration change suppression control) The acceleration change suppression control included in the control when the engine is stopped may be executed as shown in FIG. 7, which will be described later, when the target is a hybrid electric vehicle 3 having a clutch 54 as shown in the following FIG. 6.

[0051] Fig. 6 is a diagram schematically illustrating another example configuration of a hybrid electric vehicle applicable to the engine stop control according to the present disclosure. As shown in Fig. 6, the vehicle 3 includes an internal combustion engine 12, a generator 50 capable of generating electricity using power from the internal combustion engine 12, and an electric motor 52 that drives the wheels 2. The vehicle 3 also includes a clutch 54 provided in the power transmission path 4 between the internal combustion engine 12 and the wheels 2. The clutch 54 is, for example, an electromagnetic clutch, and is configured to be able to connect and disconnect the power transmission path 4 in response to a command from the ECU 40. Reference numeral 56 denotes a differential gear.

[0052] Fig. 7 is a flowchart showing another example of the flow of processing related to control when the engine is stopped according to the third embodiment. In Fig. 7, the acceleration change suppression control for the vehicle 3 shown in Fig. 6 is executed in step S400 before the full-open control (step S104) included in step S402 when a fuel cut (step S102) is executed in response to the establishment of the engine stop condition (step S100; Yes). Specifically, in this acceleration change suppression control, the ECU 40 releases the clutch 54 before the start of the full-open control. As a result, the internal combustion engine 12 is disconnected from the wheels 2 before the throttle valve 26 is brought into the fully open state.

[0053] If the acceleration change suppression control (disengagement of the clutch 54) is not performed, when the throttle valve 26 is fully opened by the full-open control, the engine braking force Feb generated during the engine stop process will be weaker than when the full-open control is not performed during the engine stop process (for example, when an idle opening is used), resulting in a change in the vehicle acceleration G. Then, as already explained, if the full-close control is performed thereafter, the engine braking force Feb will be stronger, resulting in a change in the vehicle acceleration G. In contrast, by performing the acceleration change suppression control as shown in FIG. 7, it is possible to prevent the engine braking force Feb from increasing or decreasing during the engine stop process due to the execution of the full-open control and the full-close control, and therefore it is possible to prevent a change in the vehicle acceleration G. [Explanation of symbols]

[0054] 1, 3 Hybrid electric vehicle, 2 Wheels, 4 Power transmission path, 10 Power train, 12 Internal combustion engine, 14 Electric motor (generator), 16, 52 Electric motor, 18 Power split mechanism, 24 Fuel injection device, 26 Throttle valve, 27 Exhaust purification catalyst, 28 Battery, 30 Power control unit (PCU), 32 Brake actuator, 34 Sensors, 36 Air conditioner, 38 Audio equipment, 40 Electronic control unit (ECU), 50 Generator, 54 Clutch

Claims

1. A control device applied to a hybrid electric vehicle including an internal combustion engine including a fuel injection device and a throttle valve disposed in an intake passage, and a generator capable of generating electricity using power from the internal combustion engine, When the control device stops the internal combustion engine, a fuel cut to stop the supply of fuel from the fuel injection device and a full-open control to bring the throttle valve into a full-open state; during an engine stop process after the execution of the full-open control, after the exhaust air-fuel ratio becomes lean, a full-close control is executed to bring the throttle valve into a full-close state, and an application control is executed to apply a power generation load of the generator to the internal combustion engine, The control device executes acceleration change suppression control for controlling the hybrid electric vehicle so as to suppress a change in vehicle acceleration accompanying execution of at least the full-close control of the full-open control and the full-close control. Hybrid electric vehicle control device.

2. The hybrid electric vehicle includes an electric motor that drives wheels and a brake actuator that controls braking force of the wheels, The control device When the acceleration change suppression control is executed during acceleration or steady running of the hybrid electric vehicle, the electric motor is controlled so as to increase the vehicle driving force in order to offset a decrease in the vehicle driving force corresponding to an increase in the engine braking force caused by the execution of the full closure control. When the acceleration change suppression control is executed during deceleration of the hybrid electric vehicle, the electric motor or the brake actuator is controlled so as to reduce the vehicle braking force in order to offset an increase in the vehicle braking force corresponding to the increase in the engine braking force. The control device for a hybrid electric vehicle according to claim 1.

3. the hybrid electric vehicle includes a clutch provided in a power transmission path between the internal combustion engine and wheels; In the acceleration change suppression control, the control device releases the clutch before the full-open control is started. The control device for a hybrid electric vehicle according to claim 1.

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