JP2023059718A - Control device of hybrid-type electric vehicle - Google Patents

Abstract

To quickly crank and start an engine, when receiving a request for starting the engine during execution of quick garage control.SOLUTION: When receiving a request for starting an engine during execution of quick garage control (determined YES in S2), engine-step starting control of S6 by which indicated pressure of hydraulic pressure PRk0 of an K0 clutch is increased step by step beyond constant stand-by pressure ppack is executed under a given condition (determined YES in S4 and S5), so that the K0 clutch is engaged quickly, which enables a rotary machine to crank and start the engine quickly, during return-transition in which a rotation speed Nmg of an MG increases from below a high-speed switching allowable rotation speed nquick toward a target rotation speed Nmgt (determined YES in S3).SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a hybrid electric vehicle, and more particularly to control for starting an engine during execution of garage control for switching the shift range of a transmission.

An engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, and a hydraulic friction engagement engine provided between the engine and the electric motor in the power transmission path. A connecting/disconnecting device is provided between the electric motor and the drive wheels in the power transmission path, and a plurality of shift ranges having different power transmission states according to the engagement and disengagement states of a plurality of hydraulic friction engagement devices. Hybrid electric vehicles are known that have a switchable transmission. When a friction engagement device such as the friction engagement type engine connection/disconnection device or the friction engagement device of the transmission is engaged, the standby state immediately before the friction engagement device transmits torque (hydraulic actuator After holding the instructed engagement pressure at a predetermined constant standby pressure so that the piston moves forward (packed state), the instructed engagement pressure is increased at a predetermined timing to engage the friction engagement device. is proposed. For example, the initial FILL control described in Patent Document 1 is one example.

JP-A-2000-272380

By the way, although it is not yet publicly known, regarding the control of the hybrid electric vehicle, (a) when switching the shift range of the transmission, the rotation speed of the electric motor is reduced to a predetermined high-speed switching allowable rotation speed or less; and by stepwise increasing the engagement instruction pressure of a predetermined frictional engagement device out of the plurality of frictional engagement devices to rapidly engage the gear, after switching the shift range, the rotational speed of the electric motor increases. (b) a garage control unit that executes quick garage control that allows the engine speed to return to a target rotational speed; After holding the engagement instruction pressure of the engine connection/disconnection device at a predetermined constant pressure standby pressure so that the engine connection/disconnection device is in a standby state immediately before engagement in which the engine connection/disconnection device transmits cranking torque when the engine is started, An engine start control unit for executing engine start control, which cranks the engine by increasing control of the engagement command pressure of the engine connection/disconnection device so that the cranking torque is transmitted via the engine connection/disconnection device. , is considered to be provided. In this case, if there is a request to start the engine during execution of the quick garage control, the engagement command pressure of the engine connection/disconnection device is held at the constant standby pressure, and then the engine connection/disconnection device is engaged to crank the engine. Then, depending on the timing of the start request, even if the rotation speed of the electric motor returns to the startable rotation speed at which the engine can be started, the engine connection/disconnection device may remain at the constant standby pressure, delaying cranking and start of the engine. be. That is, when the engagement command pressure of the engine connection/disconnection device is held at the constant standby pressure to enter the standby state immediately before the engagement, it takes a relatively long time to enter the standby state (packed state), so the engine is cranked. If the ranking is delayed, for example, in the case of an engine start request based on the driver's accelerator-on operation, it takes longer to obtain the desired driving force, which may cause the driver to feel sluggish.

The present invention has been made against the background of the above circumstances, and its object is to enable the engine to be quickly cranked and started when there is a request to start the engine during execution of quick garage control. It is to be

In order to achieve such an object, the present invention provides (a-1) an engine, (a-2) an electric motor coupled to a power transmission path between the engine and driving wheels, and (a -3) a hydraulic friction-engagement type engine connecting/disconnecting device provided between the engine and the electric motor in the power transmission path; and (a-4) connecting the electric motor and the driving wheels in the power transmission path. A control device for a hybrid electric vehicle, comprising: (b) when switching the shift range of the transmission, the rotation speed of the electric motor is reduced to a predetermined high-speed switching allowable rotation speed or less, and a predetermined friction coefficient among the plurality of friction engagement devices; Quick garage control is executed to allow the rotational speed of the electric motor to return to the target rotational speed after the shift range is switched by increasing the engagement instruction pressure of the coupling device in steps to rapidly engage the gear. and (c) the engine disconnecting device transmits cranking torque when the engine is started by cranking the engine by switching the engine disconnecting device from the released state to the engaged state. After holding the engagement instruction pressure of the engine connection/disconnection device at a predetermined constant pressure standby pressure so as to enter the standby state immediately before the engine connection/disconnection device, the cranking torque is transmitted through the engine connection/disconnection device. an engine start control unit that controls an increase in the engagement command pressure of the engine connection/disconnection device to crank the engine, and (d) the engine start control unit executes engine start control; When there is a request to start the engine during the execution of quick garage control, in the case of a return transition in which the rotation speed of the electric motor increases from the high-speed switching allowable rotation speed or less toward the target rotation speed, the engine An engine step start in which the engagement instruction pressure of the disconnecting device is increased stepwise beyond the constant standby pressure so that the engine disconnecting device can transmit the cranking torque without being held at the constant standby pressure. It is characterized by performing control.

According to such a control device for a hybrid electric vehicle, when there is a request to start the engine during execution of quick garage control, the rotation speed of the electric motor increases from below the allowable rotation speed for high-speed switching toward the target rotation speed. In the case of recovery transition, the engagement instruction pressure of the engine disconnecting device is increased stepwise beyond the constant pressure standby pressure, and the engine disconnecting device is quickly engaged, so that the engine is quickly started by the electric motor. It can be cranked and started. In particular, since it is the return transition time when the rotation speed of the electric motor is increased, the time until the rotation speed of the electric motor reaches the startable rotation speed at which the engine can be started is relatively short, and the engine disconnection device is placed in the standby state. Engagement without holding it properly has the effect of quickly cranking and starting the engine. Further, since it is the return transition period in which the rotation speed of the electric motor is increased, the friction engagement device of the transmission that is engaged by the quick garage control is already in the engagement state, and even if the common hydraulic supply source is used. , there is little possibility that the hydraulic pressure will be insufficient when the engagement instruction pressure of the engine disconnecting device is increased stepwise, and the quick garage control and the engine step start control can be appropriately performed.

1 is a schematic configuration diagram for explaining a drive system of a hybrid electric vehicle equipped with a control device that is an embodiment of the present invention, and also shows control functions for various controls and main parts of the control system; FIG. . 2 is a flowchart specifically explaining the operation of an engine start control unit functionally provided in the electronic control device of the hybrid electric vehicle of FIG. 1; FIG. 3 is an example of a time chart illustrating changes in operating states of various parts when engine start control is performed according to the flowchart of FIG. 2 during execution of quick garage control accompanying R→D range switching; FIG.

INDUSTRIAL APPLICABILITY The present invention is applied to a control device for a parallel hybrid electric vehicle having an engine and an electric motor as driving force sources. As the electric motor, a motor-generator that can be used alternatively as an electric motor and a generator is preferably used, but a motor that does not have the function of a generator can also be used. Hybrid electric vehicles include, for example, FR (front engine/rear drive) type rear wheel drive vehicles, front and rear wheel drive vehicles equipped with a transfer that distributes power to the front wheels, and FF (front engine) vehicles such as transaxles.・Vehicles with various drive types, such as front-wheel drive vehicles. A transmission provided between the electric motor and the driving wheels is provided with at least a plurality of hydraulic friction engagement devices, and is capable of switching between a plurality of shift ranges with different power transmission states, such as D range and R range. A stepped transmission such as a planetary gear type or a parallel shaft type that is capable of a running range of 1 and a non-running range such as an N range is preferably used. Various transmissions can be employed, such as a combination of a device and a belt-type continuously variable transmission. The friction engagement device of the transmission and the engine connection/disconnection device are configured, for example, to be supplied with hydraulic pressure from a common hydraulic supply source, but separate hydraulic supply sources may be provided.

In the present invention, for example, (a) a hydrodynamic transmission device such as a torque converter is interposed between the electric motor and the transmission, and the output of the engine and the electric motor is transmitted through the hydrodynamic transmission device. (b) the quick garage control by the garage control unit reduces the rotation speed of the electric motor to the allowable rotation speed for high-speed switching or less, so that the While the torque input to the transmission is reduced, (c) in the driving range of the D range in which the transmission can run forward or the R range in which the transmission can run in reverse, the acceleration request amount such as the accelerator opening is substantially zero. and a creep control unit for executing creep control to rotate the electric motor at a predetermined creep rotational speed so as to obtain a predetermined creep torque when the vehicle speed is at a predetermined creep vehicle speed or lower or when the vehicle is stopped. (d) when the quick garage control is executed while the creep control is being executed, the garage control unit reduces the rotation speed of the electric motor to the high-speed switching allowable rotation speed or less in preference to the creep control; configured to lower The permissible rotation speed for high-speed switching is suitably a low rotation speed at which the output torque of the torque converter (the input torque of the transmission) becomes approximately 0, for example approximately 0. It can be appropriately determined within a range in which the shock does not pose a problem. Instead of the hydrodynamic transmission device, an electric differential section having a planetary gear device and a differential control rotating machine, a friction engagement type starting clutch, or the like may be provided.

In the engine step start control by the engine start control unit, for example, after the rotation speed of the electric motor returns to the startable rotation speed at which the engine can be started by quick garage control, the engine disconnection device is engaged and the engine is started. A timing is determined for stepwise increasing the engagement instruction pressure of the engine connection/disconnection device so as to allow cranking. The timing of increasing the engagement command pressure may be after the rotation speed of the electric motor reaches the startable rotation speed, or before reaching the startable rotation speed in consideration of the response delay of the engagement torque of the engine disconnection device. But it's okay. It is also possible to engage the engine connection/disconnection device when the rotation speed of the electric motor is lower than the startable rotation speed, and increase the cranking speed of the engine while increasing the rotation speed of the electric motor. In the engine step start control, there is a possibility that an engagement shock such as driving force fluctuation may occur due to the sudden engagement of the engine connection/disconnection device. Although it may be performed only when the engine start demand is high, it is also possible to perform the engine step start control when the engine is started for other reasons such as charging the battery or warming up the engine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified for explanation, and the shapes, dimensional ratios, angles, etc. of each part are not necessarily drawn accurately.

FIG. 1 is a schematic configuration diagram of a drive system of a hybrid electric vehicle 10 (hereinafter simply referred to as an electric vehicle 10) having an electronic control device 90 as a control device according to an embodiment of the present invention. FIG. 2 is a diagram showing together control functions for various controls related to and a main part of a control system; In FIG. 1, an electric vehicle 10 is a parallel type hybrid electric vehicle that includes an engine 12 and a rotating machine MG as a driving force source for running. The electric vehicle 10 also includes a power transmission device 16 provided in a power transmission path between the engine 12 and the driving wheels 14 . The drive wheels 14 are left and right rear wheels, and the electric vehicle 10 is an FR type rear wheel drive vehicle.

The engine 12 is an internal combustion engine such as a gasoline engine or a diesel engine. In the engine 12, an engine torque Te, which is the output torque of the engine 12, is controlled by controlling an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc. by an electronic control device 90. FIG. The rotating machine MG is a motor-generator having a function as an electric motor that generates mechanical power from electric power and a function as a generator that generates power from mechanical power. It is an AC synchronous motor or the like, and is connected to a battery 54 via an inverter 52 . In the rotating machine MG, the inverter 52 is controlled by the electronic control unit 90 to control the MG torque Tmg, which is the torque of the rotating machine MG, and the MG rotational speed Nmg, which is the rotational speed of the rotating machine MG. The rotary machine MG generates power for running from electric power supplied from a battery 54 via an inverter 52 instead of or in addition to the engine 12 . When the rotary machine MG is rotationally driven by the power of the engine 12 or the driven force input from the drive wheel 14 side, the rotary machine MG is regeneratively controlled so as to function as a generator to generate power, and the drive wheel 14, it generates regenerative braking. Electric power generated by the power generation of rotating machine MG is stored in battery 54 via inverter 52 . The battery 54 is a power storage device that transfers electric power to and from the rotary machine MG. The rotating machine MG corresponds to an electric motor connected to a power transmission path between the engine 12 and the drive wheels 14 .

The power transmission device 16 includes a K0 clutch 20, a torque converter 22, and an automatic transmission 24 in series from the engine 12 side within a case 18, which is a non-rotating member attached to the vehicle body. A rotary machine MG is connected to the power transmission path between 22 . The K0 clutch 20 is a clutch provided between the engine 12 and the rotating machine MG in the power transmission path between the engine 12 and the driving wheels 14, and is used for disconnecting the connection between the rotating machine MG and the engine 12. It is a contact device. The torque converter 22 is provided between the rotary machine MG and the automatic transmission 24, is a hydrodynamic transmission device that transmits power via hydraulic fluid OIL, and is connected to the engine 12 via the K0 clutch 20. ing. The automatic transmission 24 is connected to the torque converter 22 and provided between the rotating machine MG and the driving wheels 14 in the power transmission path between the engine 12 and the driving wheels 14 . The power transmission device 16 includes a propeller shaft 28 connected to a transmission output shaft 26 which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, and a pair of drives connected to the differential gears 30. A shaft 32 and the like are provided. The power transmission device 16 also includes an engine connection shaft 34 that connects the engine 12 and the K0 clutch 20, an MG connection shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like. The rotor of the machine MG is connected.

The K0 clutch 20 is a wet-type or dry-type (wet-type in the embodiment) friction engagement device composed of a multi-plate or single-plate clutch that is pressed by a hydraulic actuator. The K0 clutch 20 changes the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, by the regulated K0 oil pressure PRk0 supplied from the hydraulic control circuit 56, thereby changing the control state such as the engaged state and the disengaged state. can be switched. An input side member of the K0 clutch 20 is connected to an engine connecting shaft 34 and is rotated integrally with the engine connecting shaft 34 . The output side member of the K0 clutch 20 is connected to the MG connecting shaft 36 and is rotated together with the MG connecting shaft 36 . In the engaged state of the K0 clutch 20, the rotor of the rotary machine MG and the pump impeller 22a and the engine 12 are integrally rotated via the engine connecting shaft . On the other hand, in the released state of the K0 clutch 20, power transmission between the rotor of the rotary machine MG and the pump impeller 22a and the engine 12 is cut off.

The rotating machine MG is connected to the MG connecting shaft 36 within the case 18 so as to be able to transmit power. The rotary machine MG is connected to a power transmission path between the engine 12 and the driving wheels 14, particularly a power transmission path between the K0 clutch 20 and the torque converter 22 so that power can be transmitted. That is, the rotary machine MG is connected to the torque converter 22 and the automatic transmission 24 without the K0 clutch 20 so that power can be transmitted. Torque converter 22 and automatic transmission 24 transmit the drive power from the drive power sources of engine 12 and rotary machine MG to drive wheels 14, respectively.

The torque converter 22 includes a pump impeller 22 a connected to the MG connecting shaft 36 and a turbine impeller 22 b connected to the transmission input shaft 38 which is an input rotating member of the automatic transmission 24 . The pump impeller 22a is connected to the engine 12 via the K0 clutch 20 and directly connected to the rotary machine MG. Pump impeller 22 a is an input member of torque converter 22 , and turbine impeller 22 b is an output member of torque converter 22 . The MG connecting shaft 36 is also an input rotating member of the torque converter 22 . The transmission input shaft 38 is also an output rotating member of the torque converter 22 integrally formed with a turbine shaft rotationally driven by the turbine impeller 22b. The torque converter 22 includes an LU clutch 40 that connects the pump impeller 22a and the turbine impeller 22b. The LU clutch 40 is a direct coupling clutch that connects the input and output rotating members of the torque converter 22, that is, a known lockup clutch.

The LU clutch 40 changes its operating state, ie, control state, by changing the LU clutch torque Tlu, which is the torque capacity of the LU clutch 40, by the regulated LU oil pressure PRlu supplied from the hydraulic control circuit 56. The control state of the LU clutch 40 includes a fully released state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slipping, and a slip state in which the LU clutch 40 is engaged. There is a state, fully engaged. By bringing the LU clutch 40 into a completely released state, the torque converter 22 is brought into a torque converter state in which a torque amplifying action can be obtained. Further, the torque converter 22 is brought into a lockup state in which the pump impeller 22a and the turbine impeller 22b are integrally rotated by the LU clutch 40 being fully engaged.

The automatic transmission 24 is a known planetary gear type automatic transmission including, for example, one or more sets of planetary gear devices and a plurality of engagement devices CB. The engagement device CB is a hydraulic friction engagement device composed of a multi-plate or single-plate clutch or brake pressed by a hydraulic actuator and a band brake tightened by a hydraulic actuator. Each of the engagement devices CB changes its CB torque Tcb, which is its torque capacity, by the regulated CB hydraulic pressure PRcb supplied from the hydraulic control circuit 56, thereby changing the control state such as the engaged state and the disengaged state. can be switched.

The automatic transmission 24 has a plurality of forward gears with different gear ratios γat (=AT input rotation speed Ni/AT output rotation speed No) by engaging any one of the engagement devices CB. It is a stepped transmission capable of forming a step and a reverse gear step. In the automatic transmission 24, an electronic control unit 90 switches between gears according to the driver's accelerator operation, vehicle speed V, and other driving conditions. be done. Further, when all of the plurality of engaging devices CB are released, the vehicle becomes neutral to cut off power transmission. The AT input rotational speed Ni is the rotational speed of the transmission input shaft 38 and the input rotational speed of the automatic transmission 24 . The AT input rotation speed Ni is also the rotation speed of the output rotation member of the torque converter 22 and has the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22 . The AT output rotation speed No is the rotation speed of the transmission output shaft 26 and the output rotation speed of the automatic transmission 24 .

In the power transmission device 16, the power output from the engine 12 is transmitted from the engine connection shaft 34 to the K0 clutch 20, the MG connection shaft 36, the torque converter 22, the automatic transmission 24 when the K0 clutch 20 is engaged. , the propeller shaft 28, the differential gear 30, the drive shaft 32, and the like in sequence to the drive wheels 14. Further, regardless of the control state of the K0 clutch 20, the power output from the rotary machine MG is transmitted from the MG connecting shaft 36 to the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, and the like. are sequentially transmitted to the drive wheels 14 through the .

The electric vehicle 10 includes a mechanical oil pump MOP 58, an electric oil pump EOP 60, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a and is driven to rotate by the driving force source (engine 12, rotary machine MG) to discharge hydraulic oil OIL used in the power transmission device 16. As shown in FIG. The pump motor 62 is an electric motor dedicated to the EOP 60 for rotating the EOP 60 . The EOP 60 is rotationally driven by the pump motor 62 to discharge hydraulic oil OIL, and can discharge the hydraulic oil OIL at any timing including when the electric vehicle 10 is stopped. Hydraulic oil OIL discharged from the MOP 58 and EOP 60 is supplied to the hydraulic control circuit 56 . The hydraulic control circuit 56 outputs CB hydraulic pressure PRcb, K0 hydraulic pressure PRk0, LU hydraulic pressure PRlu, etc., each of which is adjusted based on the hydraulic oil OIL discharged from MOP58 and/or EOP60. The hydraulic oil OIL is supplied to the torque converter 22 and used for power transmission, and is also used for lubrication and cooling of various parts. Hydraulic oil OIL is accumulated in an oil reservoir such as an oil pan provided in the lower portion of case 18 and is pumped up by MOP 58 and/or EOP 60 and supplied to hydraulic control circuit 56 . The MOP 58 and the EOP 60 are hydraulic pressure supply sources for the hydraulic control circuit 56, and hydraulic pressure is supplied from a common hydraulic pressure source to engage the K0 clutch 20, which is an engine connection/disconnection device, and the engagement device CB of the automatic transmission 24. Let me.

The electric vehicle 10 includes an electronic control device 90 as a control device that executes various controls. The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, and an input/output interface. Various controls of the electric vehicle 10 are executed by performing signal processing. The electronic control unit 90 includes a plurality of computers for engine control, MG control, hydraulic control, etc., as required.

The electronic control unit 90 includes various sensors provided in the electric vehicle 10 (for example, the engine rotation speed sensor 70, the turbine rotation speed sensor 72, the output rotation speed sensor 74, the MG rotation speed sensor 76, the accelerator opening sensor 78, the throttle Various signals based on values detected by valve opening sensor 80, brake switch 82, battery sensor 84, oil temperature sensor 86, lever position sensor 88, etc. (for example, engine rotation speed Ne, AT input rotation speed Turbine rotation speed Nt which is equivalent to speed Ni, AT output rotation speed No corresponding to vehicle speed V, MG rotation speed Nmg which is rotation speed of rotary machine MG, operation amount of accelerator operation member 79 such as an accelerator pedal, etc. The accelerator opening .theta.acc representing the amount of acceleration required, the throttle valve opening .theta.th being the opening of the electronic throttle valve, and the brake ON signal indicating that the brake pedal for operating the wheel brake is being operated by the driver. Bon, battery temperature THbat, battery charging/discharging current Ibat and battery voltage Vbat of battery 54, oil temperature THoil which is the temperature of hydraulic oil OIL in hydraulic control circuit 56, operating position POSsh of shift lever 64 provided in electric vehicle 10. , etc.) are provided respectively. The MG rotation speed Nmg has the same value as the input rotation speed Ntci of the torque converter 22, and the turbine rotation speed Nt has the same value as the output rotation speed Ntco of the torque converter 22.

The shift lever 64 is arranged near the driver's seat, is a shift operation member operated by the driver to switch the shift range, which is the power transmission state of the automatic transmission 24, and has a plurality of operation positions POSsh. As the operating position POSsh, for example, a plurality of positions P, R, N, and D are provided, and each range of P, R, N, and D can be selected as a shift range. The P position is an operating position for selecting a P (parking) range for parking in which the automatic transmission 24 is in a neutral state in which power transmission is interrupted and rotation of the transmission output shaft 26 is mechanically prevented. A neutral state is a state in which all engagement devices CB of the automatic transmission 24 are released. The R position is an operation position for selecting an R (reverse) range for reverse travel in which the automatic transmission 24 is in a reverse gear stage. The N position is an operation position for selecting the N (neutral) range in which the automatic transmission 24 is in a neutral state, like the P position. The D position is an operation for selecting a D (drive) range for forward travel in which a plurality of forward gear stages of the automatic transmission 24 are automatically switched according to driving conditions such as vehicle speed V and accelerator opening θacc. is a position. The shift lever 64 may be positioned and held at each of the P, R, N, and D operating positions POSsh, or may be of an automatic return type in which it is automatically returned to a predetermined home position. Further, a push button switch or the like for selecting each shift range may be used as the shift operation member.

From the electronic control device 90, various command signals (for example, for controlling the engine 12) are sent to each device (for example, the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.) provided in the electric vehicle 10. Engine control command signal Se, MG control command signal Smg for controlling rotary machine MG, CB hydraulic control command signal Scb for controlling engagement device CB, K0 hydraulic control command signal Sk0 for controlling K0 clutch 20 , LU oil pressure control command signal Slu for controlling the LU clutch 40, EOP control command signal Seop for controlling the EOP 60, etc.) are output respectively. The hydraulic control circuit 56 is provided with a plurality of solenoid valves for switching oil passages and controlling hydraulic pressure according to the CB hydraulic control command signal Scb, the K0 hydraulic control command signal Sk0, and the LU hydraulic control command signal Slu. The CB oil pressure control command signal Scb individually controls the CB oil pressure PRcb, which is the engagement oil pressure of each of the plurality of engagement devices CB, and corresponds to the engagement command pressure of the engagement device CB. The K0 oil pressure control command signal Sk0 controls the K0 oil pressure PRk0, which is the engagement oil pressure of the K0 clutch 20, and corresponds to the engagement instruction pressure of the K0 clutch 20. FIG.

The electronic control unit 90 functionally includes a hybrid control unit 92 , a shift control unit 94 , a creep control unit 96 , and an engine start control unit 98 in order to implement various controls in the electric vehicle 10 .

The hybrid control unit 92 has a function of cooperatively controlling the operations of the engine 12 and the rotary machine MG, and includes an engine control unit 92a that controls the engine 12 and an MG control unit 92b that controls the rotary machine MG. . The hybrid control unit 92 calculates the amount of driving demand for the electric vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The required drive amount is, for example, the required drive torque Trdem at the drive wheels 14 . The hybrid control unit 92 considers the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the torque ratio of the torque converter 22, the chargeable electric power Win and the dischargeable electric power Wout of the battery 54, and the like. A required input torque Tindem, which is the input torque of the torque converter 22 required to realize the drive torque Trdem, is obtained, and an engine control command signal Se for controlling the engine 12 is output so as to obtain the required input torque Tindem. , outputs an MG control command signal Smg for controlling the rotary machine MG. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control unit 90 based on the battery temperature THbat and the state of charge value SOC [%] of the battery 54, for example. The state-of-charge value SOC of the battery 54 is a value indicating the state of charge of the battery 54, that is, the remaining charge, and can be calculated based on, for example, the battery charging/discharging current Ibat and the battery voltage Vbat.

When the required input torque Tindem can be covered only by the output of the rotating machine MG, the hybrid control unit 92 operates in a BEV (Battery Electric Vehicle) motor running mode in which the rotating machine MG is driven only by electric power from the battery 54 to run. Run mode. In the BEV travel mode, the K0 clutch 20 is released, the engine 12 is stopped, and BEV travel is performed using only the rotary machine MG as a driving force source. In this BEV running mode, the MG torque Tmg is controlled so as to achieve the required input torque Tindem. On the other hand, when the required input torque Tindem cannot be supplied without using at least the output of the engine 12, the hybrid control unit 92 selects the HEV (Hybrid Electric Vehicle) running mode, which is the engine running mode. In the HEV travel mode, engine travel, ie, HEV travel, is performed in which the K0 clutch 20 is engaged and at least the engine 12 is used as a driving force source to travel. In this HEV running mode, the engine torque Te is controlled so as to realize all or part of the required input torque Tindem, and the MG torque Tmg is controlled so as to compensate for the shortage of the required input torque Tindem with the engine torque Te. to control. On the other hand, the hybrid control unit 92 establishes the HEV running mode when the engine 12 or the like needs to be warmed up even if the required input torque Tindem can be covered only by the output of the rotary machine MG. In this manner, the hybrid control unit 92 automatically stops the engine 12 during HEV travel, restarts the engine 12 after stopping the engine, or restarts the engine 12 during BEV travel, based on the required input torque Tindem. The BEV driving mode and the HEV driving mode are switched by starting the vehicle, automatically stopping the engine 12 while the vehicle is stopped, or starting the engine 12 .

When the D range is selected, the shift control unit 94 determines the shift of the automatic transmission 24 using a predetermined shift map or the like using the driving conditions such as the vehicle speed V and the accelerator opening θacc as variables. Automatic shift control is executed to output a CB hydraulic control command signal Scb to the hydraulic control circuit 56 for automatically switching a plurality of forward gears of the automatic transmission 24 as required. When the driver operates the shift lever 64 or a manual shift operation member provided near the driver's seat and a shift command signal is supplied, the forward gear stage of the automatic transmission 24 is switched according to the shift command. Execute manual shift control.

The shift control unit 94 also includes a garage control unit 94a that switches the shift range of the automatic transmission 24 according to the switched operation position POSsh when the shift lever 64 is operated to switch the operation position POSsh. there is Garage control unit 94a shifts automatic transmission 24 from one of the D range and the R range to the other in accordance with the reverse shift operation of switching shift lever 64 from one of the D and R positions to the other. In addition to performing reverse range switching to switch to , various range switching is performed to switch the shift range between the non-driving ranges of the P and N ranges and the driving ranges of the D and R ranges. A vehicle speed limit is provided for such range switching as necessary. Specifically, the reverse shift operation may be a D→R shift operation from the D position to the R position or an R→D shift operation from the R position to the D position via the N position. When the D→R shift operation is performed, the garage control unit 94a outputs a reverse range switching signal for switching the automatic transmission 24 from the D range to the R range, that is, a CB hydraulic control command signal for switching from the forward gear stage to the reverse gear stage. D→R range switching for outputting Scb to the hydraulic control circuit 56 is executed. Further, when the R→D shift operation is performed, the garage control unit 94a performs reverse range switching for switching the automatic transmission 24 from the R range to the D range, that is, CB hydraulic control for switching from the reverse gear stage to the forward gear stage. The command signal Scb is output to the hydraulic control circuit 56 to switch the R→D range.

For example, by engaging the first engagement device CB1 and the third engagement device CB3 among the plurality of engagement devices CB of the automatic transmission 24, for example, the transmission gear ratio γat is formed, the automatic transmission 24 is set to the D range, and the second engagement device CB2 and the third engagement device CB3 are engaged to form the reverse gear. When the automatic transmission 24 is set to the R range, the CB1 hydraulic pressure PRcb1 and the CB2 hydraulic pressure are set so that the first engagement device CB1 is released and the second engagement device CB2 is engaged in the D→R range switching. PRcb2 is controlled. Further, in the R→D range switching, the CB2 oil pressure PRcb2 and the CB1 oil pressure PRcb1 are controlled so that the second engagement device CB2 is released and the first engagement device CB1 is engaged.

Here, when any one of the plurality of engagement devices CB is to be engaged during range switching including reverse range switching, the garage control unit 94a gradually increases the indicated pressure of the hydraulic pressure PRcon of the engagement side engagement device CBcon. In addition to the normal garage control for smoothly engaging the engagement side engagement device CBcon by increasing the indicated pressure of the hydraulic pressure PRcon of the engagement side engagement device CBcon in a stepwise manner, the engagement side engagement device It has a function to perform quick garage control to quickly engage CBcon and perform range switching in a short time. For example, in the D→R range switching, the second engagement device CB2 is the engagement side engagement device CBcon, and the command pressure of the hydraulic pressure PRcb2 of the second engagement device CB2 is increased at a predetermined rate of increase under normal garage control. While it is gradually increased, the quick garage control is increased step by step. Also, in the R→D range switching, the first engagement device CB1 is the engagement side engagement device CBcon, and the indicated pressure of the hydraulic pressure PRcb1 of the first engagement device CB1 is gradually increased at a predetermined rate of increase under normal garage control. On the other hand, the quick garage control increases it step by step. In this case, if the input torque of the automatic transmission 24 is high, a shock will occur due to the sudden engagement of the engaging device CBcon on the engagement side. A quick garage for rapidly engaging the engaging device CBcon while the output torque of the torque converter 22, that is, the input torque of the automatic transmission 24, is sufficiently reduced by reducing the rotation speed to the allowable rotation speed nquick or less. Take control. The high-speed switching permissible rotation speed nquick is determined in advance by experiments and simulations so that the shock due to the sudden engagement of the engagement side engagement device CBcon is within a predetermined permissible range. . The high-speed switching permissible rotation speed nquick may be variably set according to vehicle conditions such as the vehicle speed V and the turbine rotation speed Nt. In the quick garage control, the MG rotational speed Nmg is set to be equal to or lower than the high-speed switching permissible rotational speed nquick, and the drive torque Tr of the electric vehicle 10 is limited. This is executed when predetermined quick execution conditions are met, such as when the accelerator is off when the degree .theta.acc is approximately 0, when the brake is on when the brake-on signal Bon is supplied, and when the road surface is flat with a slope of a predetermined value or less.

FIG. 3 is an example of a time chart when the quick garage control is started at time t1 and the R→D range is switched along with the R→D shift operation. After lowering the hydraulic pressure PRcb2 of the engagement device CB2, the indicated pressure of the hydraulic pressure PRcb1 of the first engagement device CB1, which is the engagement side engagement device CBcon, is increased in a stepwise manner so that the first engagement device CB1 can be rapidly engaged to execute R→D range switching in a short time. At time t1 when the R→D shift operation is performed, the accelerator opening θacc is substantially zero and the accelerator is off. , is set to a predetermined creep rotational speed ncreep so as to obtain a predetermined creep torque Tcreep. For this reason, the garage control unit 94a gives priority to the creep control prior to stepwise increasing the command pressure of the hydraulic pressure PRcb1 of the first engagement device CB1, which is the command pressure of the engagement side engagement device CBcon. Then, the MG rotational speed Nmg is reduced at a predetermined rate of change below the high-speed switching permissible rotational speed nquick, and the creep torque Tcreep is sufficiently reduced to achieve a creep cut state. As a result, the R→D range switching can be performed in a short time while suppressing the occurrence of a shock due to the sudden engagement of the engagement side engagement device CBcon.

When the hydraulic pressure PRcb1 on the engagement side rises to substantially engage the first engagement device CB1 and the R→D range switching is substantially completed (time t2 in FIG. 3), the garage control unit 94a controls the MG rotation speed Nmg is lifted to permit a return to a predetermined target rotational speed Nmgt. Whether or not the R→D range switching has been substantially completed, that is, whether or not the first engagement device CB1 has been substantially engaged is determined, for example, from the start of engagement control for stepwise increasing the indicated pressure of the hydraulic pressure PRcb1. The determination can be made based on the elapsed time, and the timing for releasing the restriction on the MG rotation speed Nmg is determined based on the elapsed time. 3 where the R→D range is switched, since the automatic transmission 24 is in the D range, the creep rotation speed ncreep of the creep control by the creep control unit 96 becomes the target rotation speed Nmgt, and the MG rotation speed Nmg is the target rotation speed Nmgt. It is increased at a predetermined rate of change up to the rotation speed nceep.

In this case, in the reversal range switching, the creep torque Tcreep is reversed when the forward and backward gears of the automatic transmission 24 are switched, and the backlash of each part of the automatic transmission 24 and the differential gear 30, which are gear mechanisms, causes play. Hitting shock may occur. Therefore, in the present embodiment, the MG rotation speed Nmg, which is the input rotation speed Ntci of the torque converter 22, stagnates for a predetermined time at a predetermined backlash reduction rotation speed nstuff that is lower than the creep rotation speed ncreep, as shown in FIG. Backlash elimination control is performed to control the MG torque Tmg as follows. That is, when the input rotational speed Ntci is maintained at a relatively low backlash-reducing rotational speed nstuff, the output torque of the torque converter 22, that is, the torque transmitted to the automatic transmission 24 and the differential gear 30 is small. The rattling shock caused by the backlash caused by the reversal is reduced by reducing the rattling speed.

Returning to FIG. 1, the creep control unit 96 responds to the acceleration request amount in a state where the shift lever 64 is in the D position or the R position and the automatic transmission 24 is in the D range or the R range. When the accelerator opening θacc is approximately 0 and the vehicle speed V is at or below a predetermined creep vehicle speed or when the vehicle is stopped, the torque converter 22 is adjusted so that a predetermined creep torque Tcreep can be obtained as the driving torque Tr of the electric vehicle 10. creep control is executed to control the input rotational speed Ntci (=Nmg) of the . When the K0 clutch 20 is released and the engine 12 is disconnected from the power transmission path, the rotating machine MG is controlled to generate a creep torque Tcreep through the torque converter 22 . That is, in a state in which power is transmitted from the MG connecting shaft 36 to the transmission input shaft 38 side via the torque converter 22 with the LU clutch 40 in a completely released state, the input rotation speed Ntci of the torque converter 22 creeps to a predetermined level. A predetermined creep torque Tcreep can be generated by controlling the MG torque Tmg so that the rotational speed ncreep is obtained. The creep rotational speed ncreep is set to a rotational speed approximately equal to the idle rotational speed Neidl of the engine 12, for example, but may be independently set regardless of the idle rotational speed Neidl. Also, different creep rotation speeds ncreep may be determined for the D range and the R range, or may be variably set according to the oil temperature THoil of the hydraulic oil OIL flowing through the torque converter 22 or the like. When the K0 clutch 20 is engaged, a predetermined creep torque Tcreep can be generated by operating the engine 12 at an idle rotational speed Neidl or the like.

The engine start control unit 98 engages the K0 clutch 20 and rotates when there is an engine start request such as by operating the accelerator operation member 79 while the engine 12 is stopped with the K0 clutch 20 released. The engine 12 is cranked by the machine MG, and when the engine rotation speed Ne reaches a predetermined startable rotation speed negstart, ignition control such as fuel injection and ignition is performed to start the engine 12 so that it can rotate by itself. , engine start control. Engagement control of the K0 clutch 20 for cranking the engine 12 is executed by outputting a K0 oil pressure control command signal Sk0 to the oil pressure control circuit 56 to control the K0 oil pressure PRk0. The hydraulic actuator is packed by maintaining the command pressure of the K0 hydraulic pressure PRk0, which is the engagement command pressure, at a predetermined constant pressure standby pressure ppack. Packing of the hydraulic actuator is the operation of moving the piston forward to bring the K0 clutch 20 into a state just before it has engagement torque, i.e., a standby state just before transmitting cranking torque. preset based on After the packing is completed, the K0 oil pressure PRk0 is controlled to increase so that the cranking torque is transmitted through the K0 clutch 20, and the K0 clutch 20 is slip-engaged to crank the engine 12. The engine rotation speed Ne is increased to the startable rotation speed negstart or higher. Packing takes time, but it is possible to smoothly engage the K0 clutch 20 after that. , the K0 clutch 20 can be engaged and the engine 12 can be quickly cranked.

The dashed line shown as a comparative example in the columns of the K0 oil pressure PRk0 and the K0 clutch torque Tk0 in the time chart of FIG. In the case of engagement and cranking, after time t6 when the K0 oil pressure PRk0 is increased after the constant pressure standby and the K0 clutch torque Tk0 begins to increase, the slip engagement of the K0 clutch 20 causes the engine rotation speed Ne to increase. . When the K0 clutch 20 is slip-engaged to increase the engine speed Ne, the inertia of the engine 12 and the like cause drive torque fluctuations. Therefore, the torque Tmg of the rotary machine MG is controlled so as to suppress the drive torque fluctuations. Execute cranking torque compensation control. Specifically, the MG torque Tmg is increased by the cranking torque corresponding to the K0 clutch torque Tk0 so that the required input torque Tindem is maintained regardless of the increase in the engine speed Ne.

The engine start control unit 98 also displays a solid line in the column of K0 oil pressure PRk0 in FIG. As shown, the indicated pressure of the K0 oil pressure PRk0 is stepwise increased beyond the constant standby pressure ppack so that the K0 clutch 20 can transmit the cranking torque without being held at the constant standby pressure ppack. 20 is rapidly engaged to crank the engine 12, thereby performing engine step start control. That is, in the quick garage control, the MG rotation speed Nmg is made equal to or lower than the high-speed switching permissible rotation speed nquick, and after the engagement side engagement device CBcon is engaged, the restriction on the MG rotation speed Nmg is lifted and returned to the target rotation speed Nmgt. Therefore, depending on the timing of the engine start request, even if the MG rotation speed Nmg exceeds the startable rotation speed negstart, there is a possibility that the engine 12 cannot be quickly cranked by engaging the K0 clutch 20. There is For example, as indicated by the dashed line in the column of K0 oil pressure PRk0 in FIG. 3, when normal engine start control is started at time t3 at which the engine start request is made, that is, control to keep the indicated pressure of K0 oil pressure PRk0 at the constant standby pressure ppack. , after time t6 when the K0 clutch torque Tk0 begins to rise, the slip engagement of the K0 clutch 20 causes the engine speed Ne to increase, and the MG speed Nmg reaches the startable speed negstart at a time t4. to be late. On the other hand, as indicated by the solid line in the column of K0 oil pressure PRk0 in FIG. The slip engagement of the clutch 20 allows the engine rotation speed Ne to be increased, so that the engine 12 can be started quickly. In this engine step start control as well, the MG torque Tmg is controlled so as to suppress drive torque fluctuations caused by the inertia of the engine 12 after time t5 when the engine speed Ne is increased by the slip engagement of the K0 clutch 20. Execute cranking torque compensation control.

FIG. 2 is a flowchart specifically explaining the engine step-start control, in which signal processing is executed according to steps S1 to S8 (hereinafter simply referred to as S1 to S8, omitting the steps). The step start condition is that all of the determinations in S2, S3, and S4 in FIG. 2 are YES (affirmative).

In S1 of FIG. 2, the garage control unit 94a determines whether or not the quick garage control is being executed. If the quick garage control is being executed, S2 and subsequent steps are executed. Whether or not the quick garage control is being executed can be determined, for example, by providing a flag indicating whether or not the quick garage control is being executed. It is also possible to judge from vehicle conditions such as .theta.acc and MG rotational speed Nmg.

In S2, it is determined whether or not there is an engine start request, and if there is an engine start request, S3 and subsequent steps are executed, but if there is no engine start request, the process ends. The condition for the engine start request is that the K0 clutch 20 is disengaged and the engine 12 is in a stopped state. It is determined whether or not an engine start request has been supplied from the hybrid control unit 92 or the like for reasons such as the accelerator being turned on, the battery 54 being charged, the engine 12 being warmed up, or the like. In this embodiment, S3 and subsequent steps are executed for all engine start requests regardless of the reason for the engine start request. Regardless of the cranking torque compensation control by the MG, sudden engagement of the K0 clutch 20 may cause a shock such as a fluctuation in the driving force, so a predetermined degree of urgency such as when the driver turns on the accelerator S3 and subsequent steps may be executed only when an engine start request is made. That is, if the determination in S2 is YES, following S2, it is determined whether or not it is an engine start request with a high degree of urgency. In this case, normal engine start control in S8 may be executed.

In S3, it is determined whether or not the quick garage control is being restored, that is, the engagement side engagement device CBcon is substantially engaged, the restriction on the MG rotation speed Nmg is lifted, and the return to the target rotation speed Nmgt is allowed. Whether it is after time t2 in FIG. 3 is determined based on, for example, a change in the MG rotation speed Nmg. In FIG. 3, the first engagement device CB1 is the engagement side engagement device, and the restriction on the MG rotation speed Nmg is released based on the elapsed time from the start of the engagement control in which the indicated pressure of the hydraulic pressure PRcb1 is increased stepwise. If the timing to start is determined, it may be determined whether or not the quick garage control is being restored from the elapsed time. Also, in S4, it is determined whether or not the MG rotation speed Nmg is equal to or higher than a predetermined step start determination rotation speed njdg. However, in the case of NO (negative), normal engine start control in S8 is executed. As indicated by the broken line in the column of the K0 oil pressure PRk0 in FIG. 3, the normal engine start control is a control in which the indicated pressure of the K0 oil pressure PRk0 is held at the constant standby pressure ppack for a predetermined time, and the MG rotation speed Nmg is the startable rotation speed. After reaching negstart, the K0 oil pressure PRk0 is increased to crank the engine 12 and start it.

The step start determination rotation speed njdg in S4 is a rotation speed lower than the startable rotation speed negstart by a predetermined rotation speed α (see FIG. 3). The predetermined rotation speed α is set when the engine step start control is started when the MG rotation speed Nmg reaches the startable rotation speed negstart as indicated by the solid line in the column of the K0 oil pressure PRk0 in FIG. When the cranking of the engine 12 is performed earlier by the engine step start control than when the engine start control is immediately executed, Nmg≧njdg and the determination in S4 is YES. It is determined in advance by experiments, simulations, etc., based on the time to keep the indicated pressure of K0 oil pressure PRk0 at the constant pressure standby pressure ppack in the engine start control, and the rate of change when restoring the MG rotation speed Nmg in quick garage control. . If the holding time of the constant standby pressure ppack, the rate of change of the MG rotation speed Nmg, etc. are constant and the time required until cranking is substantially constant, a constant value is determined as the predetermined rotation speed α, but changes in the control conditions If the time required for cranking changes for some reason, it is desirable to variably set the predetermined rotational speed α accordingly.

FIG. 3 shows a case where an engine start request is made at time t3 in accordance with the ON operation of the accelerator operation member 79, and the MG rotation speed Nmg is higher than the step start determination rotation speed njdg, so the determination in S4 becomes YES. Then S5 is executed. In S5, it is determined whether or not the MG rotation speed Nmg is equal to or higher than the startable rotation speed negstart, and if Nmg≧negstart, the engine step start control in S6 is executed. In the case of Nmg<negstart, execution of engine start control is delayed in S7, and after a series of signal processing is completed, S1 and subsequent steps are executed. All of the determinations in S1 to S4 are YES, and S5 is repeated. When Nmg≧negstart, and the determination in S5 becomes YES, the engine step start control is started in S6. In the case of FIG. 3, at time t3 when the engine start request is made, Nmg<negstart, and after waiting until time t4 when Nmg≧negstart, the engine step start control is started as indicated by the solid line in the column of K0 oil pressure PRk0. be. In this case, cranking of the engine 12 is started at time t5, but if normal engine start control is started at time t3 when the engine start request is made as indicated by the dashed line, engine 12 is started at time t6. Since cranking is started, the engine 12 can be cranked and started earlier by the time β in this embodiment. This improves the responsiveness from the drive force request time (time t3) due to the driver's accelerator-on operation until the engine 12 can obtain a predetermined drive force.

Here, as indicated by the solid line in the column of the K0 oil pressure PRk0 in FIG. Since there is a predetermined delay time tlag (=t5-t4) from when the K0 clutch 20 generates the engagement torque to when the cranking of the engine 12 starts, the engine step start control in S6 is delayed by the delay time tlag. You may wish to start earlier. For example, based on the rate of change of the MG rotation speed Nmg when the quick garage control is restored, an advance rotation speed corresponding to the delay time tlag is obtained, and the rotation speed is lower than the startable rotation speed negstart by that advance rotation speed. The engine step start control in S6 may be started at the stage of returning to.

As described above, according to the engine start control unit 98 provided in the electronic control unit 90 of the electric vehicle 10 of this embodiment, when there is a request to start the engine 12 during execution of the quick garage control, the MG rotation speed Nmg is In the case of a return transition in which the rotation speed is increased from the allowable rotation speed nquick or lower to the target rotation speed Nmgt, the indicated pressure of the hydraulic pressure PRk0 of the K0 clutch 20 is constant under certain conditions (judgments in S4 and S5 are YES). Since the engine step start control of S6 is executed to increase the standby pressure ppack stepwise beyond the standby pressure ppack, and the K0 clutch 20 is quickly engaged, the engine 12 can be quickly cranked and started by the rotary machine MG. can be done. In particular, since the MG rotation speed Nmg is increased during the return transition, the time until the MG rotation speed Nmg reaches the startable rotation speed negstart is relatively short, and the K0 clutch 20 is engaged without being held in the standby state. The effect of quickly cranking and starting the engine 12 can be obtained appropriately. Further, since it is the return transition time when the MG rotation speed Nmg is increased, the engagement side engagement device CBcon that is engaged by the quick garage control is already in the engagement state, and the common hydraulic supply source (MOP58, EOP60). Even with the hydraulic control circuit 56 using can be implemented.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, this is only one embodiment, and the present invention can be implemented in a mode in which various modifications and improvements are added based on the knowledge of those skilled in the art. can be done.

10: Hybrid electric vehicle 12: Engine 14: Drive wheel 16: Power transmission device (power transmission path) 20: K0 clutch (engine connection/disconnection device) 24: Automatic transmission (transmission) 90: Electronic control device (control device ) 94a: Garage control unit 98: Engine start control unit MG: Rotating machine (electric motor) CB, CB1, CB2, CB3: Engagement device (friction engagement device of transmission) PRcb1: Hydraulic pressure of first engagement device CB1 ( Engagement side engagement device) PRk0: K0 oil pressure (engine disconnection device engagement pressure) Nmg: MG rotation speed (motor rotation speed) Nmgt: Target rotation speed nquick: Allowable rotation speed for high speed switching ppack: Constant pressure standby pressure

Claims (1)

An engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, and a hydraulic friction engagement engine provided between the engine and the electric motor in the power transmission path. A connecting/disconnecting device is provided between the electric motor and the drive wheels in the power transmission path, and a plurality of shift ranges having different power transmission states according to the engagement and disengagement states of a plurality of hydraulic friction engagement devices. A control device for a hybrid electric vehicle comprising a switchable transmission,
When switching the shift range of the transmission, the rotation speed of the electric motor is reduced to a predetermined high-speed switching allowable rotation speed or less, and a predetermined friction engagement device among the plurality of friction engagement devices is engaged. A garage control unit that executes quick garage control, allowing the rotation speed of the electric motor to return to the target rotation speed after switching the shift range by increasing the command pressure stepwise to cause abrupt engagement. and,
When the engine connecting/disconnecting device is switched from the released state to the engaged state and the engine is started by cranking the electric motor, the engine connecting/disconnecting device enters a standby state immediately before transmitting cranking torque. After holding the engagement instruction pressure of the engine connection/disconnection device at a predetermined constant pressure standby pressure, the engine connection/disconnection device is instructed to engage so that the cranking torque is transmitted via the engine connection/disconnection device. an engine start control unit that controls the pressure to crank the engine and executes engine start control;
and
The engine start control unit performs a return transition in which the rotation speed of the electric motor rises from the high-speed switching allowable rotation speed or less toward the target rotation speed when there is a request to start the engine during execution of the quick garage control. In the case of time, the engagement instruction pressure of the engine disconnecting device exceeds the constant pressure standby pressure so that the engine disconnecting device can transmit the cranking torque without maintaining it at the constant pressure standby pressure. A control device for a hybrid electric vehicle, characterized by performing engine step start control that increases stepwise.

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