Hybrid electric vehicle control device

Abstract

To enable a hybrid electric vehicle to travel with an engine by engaging an engine connection / disconnection device thereby starting the engine even when driving of an electric oil pump is restricted.SOLUTION: In the case of pump driving restriction (Yes for S2 determination) in which driving of EOP (an electric oil pump) is restricted when a Ready-On operation is performed in a Ready-Off state, a rotary machine MG is rotationally driven consequently a K0 clutch (i.e., an engine connection / disconnection device ) is engaged by hydraulic pressure output from an MOP (i.e., a mechanical oil pump), the engine is started by performing push start control for starting the engine by cranking through the engagement control of the K0 clutch, and establishing an HEV Ready On state in which an HEV travel on the engine as driving power source is enabled, and therefore, it is possible to secure such an appropriate travel performance that the vehicle can be started on the engine even when driving the pump is restricted.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid electric vehicle, and particularly to control for starting an engine according to a Ready ON operation to bring the vehicle into a Ready ON state.

Background Art

[0002] (a) An engine and an electric motor used as driving power sources, (b) an engine disconnecting device which is a hydraulic friction engagement device for connecting and disconnecting power transmission between the engine and the electric motor, (c) a mechanical oil pump which outputs hydraulic pressure used when engaging the engine disconnecting device by being rotationally driven by at least the electric motor of the driving power source, and (d) an electric oil pump which outputs hydraulic pressure used when engaging the engine disconnecting device by being rotationally driven by a pump electric motor, are known in a hybrid electric vehicle. The vehicle described in Patent Document 1 is an example thereof, and a technique is described in which when there is a start request for the engine, after driving the electric oil pump to engage the engine disconnecting device, the engine is cranked and started while increasing the rotational speed of the electric motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a Ready OFF state where driving by the driving power source is impossible, when a Ready ON operation for enabling driving by the driving power source is performed, if the driving of the electric oil pump is restricted due to some abnormality or the like, the engine disconnecting device cannot be engaged by the electric oil pump to start the engine, so there is a possibility that the driving performance may be impaired.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to start the engine by engaging the engine connection / disconnection device and enable the engine to run even when the driving of the electric oil pump is restricted.

Means for Solving the Problems

[0006] In order to achieve such an object, a first invention provides a control device for a hybrid electric vehicle including: (a) an engine and an electric motor used as driving power sources; (b) an engine connection / disconnection device which is a hydraulic friction engagement device for connecting and disconnecting power transmission between the engine and the electric motor; (c) a mechanical oil pump that outputs hydraulic pressure used when engaging the engine connection / disconnection device by being rotationally driven by at least the electric motor of the driving power source; and (d) an electric oil pump that outputs hydraulic pressure used when engaging the engine connection / disconnection device by being rotationally driven by a pump electric motor. In the control device, when a READY ON operation for enabling driving by the driving power source is performed in a READY OFF state where the driving power source is stopped and driving by the driving power source is impossible, it is determined whether it is a pump drive restriction time when the driving of the electric oil pump is restricted. When it is the pump drive restriction time, the engine is cranked and started by push start control in which the electric motor is rotationally driven to engage the engine connection / disconnection device by the hydraulic pressure output from the mechanical oil pump, and the rotational speed of the engine is increased by the engagement control of the engine connection / disconnection device, and a READY ON control unit that sets the engine to a READY ON state where driving with the engine as the driving power source is possible. 、 has and when the READY ON operation is performed in the READY OFF state and it is not during the pump drive constraint, the READY ON control unit drives the electric oil pump to engage the engine disconnecting device, and then cranks and starts the engine by electric motor starting control that increases the engine rotation speed while increasing the rotation speed of the electric motor, and sets it to the READY ON state where drive running with the engine as the driving power source is possible. When the READY ON operation is performed in the READY OFF state, the READY ON control unit immediately starts the engine by the push start control and sets it to the READY ON state where drive running with the engine as the driving power source is possible during the pump drive constraint. On the other hand, when it is not during the pump drive constraint, it selects whether to start the engine by the electric motor starting control and set it to the READY ON state where drive running with the engine as the driving power source is possible, or to set it to the READY ON state where drive running with the electric motor as the driving power source is possible without starting the engine. It is characterized by the above.

Effects of the Invention

[0009] In such a control device for a hybrid electric vehicle, when a Ready ON operation is performed in the Ready OFF state, in the case of pump drive restriction where the drive of the electric oil pump is restricted, the motor is rotationally driven to engage the engine disconnect device by the hydraulic pressure output from the mechanical oil pump, and push start control is performed to crank the engine by the engagement control of the engine disconnect device to start the engine, and to set the vehicle to the Ready ON state where drive running with the engine as the drive power source is possible, so that the running performance can be appropriately ensured, such as the engine can start even in the case of pump drive restriction. Also, when the READY ON operation is performed in the READY OFF state and it is not during the pump drive constraint, after driving the electric oil pump to engage the engine disconnecting device, electric motor starting control is performed to crank the engine while increasing the rotation speed of the electric motor, and the engine is started, and it is set to the READY ON state where drive running with the engine as the driving power source is possible. Therefore, the engine can be started while suppressing the load on the engine disconnecting device, and appropriate running performance can be ensured. Also, when the READY ON operation is performed in the READY OFF state, when it is during the pump drive constraint, the engine is immediately started by the push start control and set to the READY ON state where drive running with the engine as the driving power source is possible. On the other hand, when it is not during the pump drive constraint, it selects whether to start the engine by the electric motor starting control and set it to the READY ON state where drive running with the engine as the driving power source is possible, or to set it to the READY ON state where drive running with the electric motor as the driving power source is possible. Therefore, appropriate running performance can be ensured by starting the engine regardless of whether it is during the pump drive constraint or not. Also, according to the electric motor starting control, the engine can be quickly started in response to the engine start request even when the vehicle is stopped. Therefore, it is possible to suppress the engine start while ensuring the driving force responsiveness and improve the fuel efficiency.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0013] The present invention is applied to a control device for a parallel hybrid electric vehicle equipped with an engine and an electric motor as driving power sources. As the electric motor, a motor generator that can also be used as a generator is preferably used, but an electric motor that cannot obtain the function of a generator can also be adopted. It may be equipped with a plurality of electric motors or motor generators. The hybrid electric vehicle may be, for example, an FR (front engine - rear drive) type rear - wheel drive vehicle, a front - and - rear - wheel drive vehicle provided with a transfer that distributes power to the front - wheel side in the middle, an FF (front engine - front drive) type front - wheel drive vehicle such as a transaxle, and various types of drive - type vehicles are targeted. In the power transmission path between the driving power source and the drive wheels, a fluid transmission device, a transmission, etc. are provided as necessary, and the electric motor can be rotationally driven while maintaining the vehicle stop state by cutting off the power transmission. In order to cut off the power transmission, an electric differential unit having a planetary gear device and a differential - control rotating machine, a friction - engagement type starting clutch, etc. may be provided.

[0014] The ready - ON operation for enabling driving by the driving power source is, for example, an operation when starting the vehicle, such as pressing or rotating an operation of a power switch, an ignition switch, a start / stop switch, etc., and may include other operations such as the shift lever position and the presence or absence of a brake operation as conditions. Not limited to the ready - ON operation from ignition - OFF or power - OFF, an accessory - ON state in which power is supplied to accessory products is also in the ready - OFF state if driving by the driving power source is impossible, and a ready - ON operation from such an accessory - ON state may also be acceptable. A ready - changeover switch or the like for switching between the ready - ON state and the ready - OFF state may be provided separately. When there is a pump - drive constraint where the drive of the electric oil pump is restricted, it may be due to an abnormality in the electrical system such as a disconnection of the pump - driving electric motor or an abnormality in the pump itself such as a malfunction of the electric oil pump, or a constraint caused by factors other than the pump such as the temperature of the battery or the working oil.

[0015] When the READY ON operation is performed and there is a pump drive constraint, it is desirable to always start the engine immediately by push start control to enter the READY ON state where drive running using the engine as the power source is possible. However, various modes are possible, such as starting the engine by push start control to enter the READY ON state when starting conditions such as an engine start request are satisfied. When there is no pump drive constraint, it is desirable to start the engine by electric motor start control, but it is also possible to start the engine by push start control to enter the READY ON state as in the case of pump drive constraint.

Embodiment

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or deformed for the purpose of explanation, and the dimensional ratios, angles, shapes, etc. of each part are not necessarily accurately drawn.

[0017] FIG. 1 is a schematic configuration diagram of a drive system of a hybrid electric vehicle 10 (hereinafter simply referred to as the electric vehicle 10) including an electronic control unit 90 as a control device according to an embodiment of the present invention, and shows a control function for various controls related to the electric vehicle 10 and main parts of the control system together. In FIG. 1, the electric vehicle 10 is a parallel hybrid electric vehicle including an engine 12 and a rotating electric machine MG as a driving power source for traveling, and the rotating electric machine MG corresponds to an electric motor. Further, the electric vehicle 10 includes a power transmission device 16 provided in the power transmission path between the engine 12 and the drive wheels 14. The drive wheels 14 are the left and right rear wheels, and the electric vehicle 10 is an FR-type rear-wheel drive vehicle with the engine 12 and the rotating electric machine MG mounted on the front side of the vehicle.

[0018] The engine 12 is an internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 has its output torque, i.e., the engine torque Te, controlled by the electronic control unit 90 controlling engine control equipment 50 including a throttle actuator, a fuel injection device, an ignition device, etc. The rotating electric 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 electric power from mechanical power, and is, for example, a three-phase AC synchronous motor, etc., and is connected to the battery 54 via the inverter 52. The rotating electric machine MG has its torque, i.e., the MG torque Tmg, and its rotational speed, i.e., the MG rotational speed Nmg, controlled by the electronic control unit 90 controlling the inverter 52. The rotating electric machine MG generates driving power for traveling by the electric power supplied from the battery 54 via the inverter 52, instead of or in addition to the engine 12. The rotating electric machine MG also performs power generation by being regeneratively controlled to function as a generator when it is rotationally driven by the power of the engine 12 or the driven power input from the drive wheel 14 side, and generates a regenerative brake when connected to the drive wheel 14. The electric power generated by the power generation of the rotating electric machine MG is stored in the battery 54 via the inverter 52. The battery 54 is a power storage device that exchanges electric power with the rotating electric machine MG.

[0019] The power transmission device 16 includes, within a case 18 which is a non-rotating member attached to the vehicle body, a K0 clutch 20, a torque converter 22, and an automatic transmission 24 in series from the engine 12 side, and a rotary electric machine MG is connected to the power transmission path between the K0 clutch 20 and the torque converter 22. The K0 clutch 20 is an engine disconnecting and connecting device provided between the engine 12 and the rotary electric machine MG in the power transmission path between the engine 12 and the drive wheels 14, and is a hydraulic friction engagement device that connects and disconnects the power transmission between the rotary electric machine MG and the engine 12. The torque converter 22 is provided between the rotary electric machine MG and the automatic transmission 24, and is a fluid transmission device that transmits power via a working oil OIL which is a fluid, and is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22, and is a transmission provided in series with the torque converter 22 between the engine 12 and the rotary electric machine MG and the drive wheels 14. The power transmission device 16 includes a propeller shaft 28 connected to an output shaft 26 which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like. Further, the power transmission device 16 includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, an MG connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like, and the rotor of the rotary electric machine MG is connected to the MG connecting shaft 36.

[0020] The K0 clutch 20 is a wet or dry (wet in the embodiment) friction engagement device composed of a multi-plate or single-plate clutch pressed by a hydraulic actuator. The K0 clutch 20 has its control states such as the engaged state and the released state switched by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, by the regulated K0 hydraulic pressure PRk0 supplied from the hydraulic control circuit 56. Examples of the control states of the K0 clutch 20 include a released state in which the K0 clutch 20 is completely released, a slip engagement state in which the K0 clutch 20 is engaged with slippage, and a full engagement state in which the K0 clutch 20 is completely engaged. In the full engagement state of the K0 clutch 20, the rotor of the rotating electric machine MG, the pump impeller 22a, and the engine 12 are integrally rotated via the engine connection shaft 34. In the released state of the K0 clutch 20, the power transmission between the rotor of the rotating electric machine MG, the pump impeller 22a, and the engine 12 is blocked, and the engine 12 can be stopped.

[0021] The torque converter 22 includes a pump impeller 22a connected to the MG connection shaft 36 and a turbine impeller 22b connected to the input rotating member of the automatic transmission 24, which is the input shaft 38. The pump impeller 22a is connected to the engine 12 via the K0 clutch 20 and is directly connected to the rotating electric machine MG. The pump impeller 22a is the input member of the torque converter 22, and the turbine impeller 22b is the output member of the torque converter 22. The MG connection shaft 36 is also the input rotating member of the torque converter 22. The input shaft 38 is also the output rotating member of the torque converter 22, which is integrally formed with the turbine shaft rotated 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 connection clutch that connects the input and output rotating members of the torque converter 22, that is, a lock-up clutch.

[0022] The LU clutch 40 has its operating state, i.e., control state, switched by changing the LU clutch torque Tlu, which is the torque capacity of the LU clutch 40, by the regulated LU hydraulic pressure PRlu supplied from the hydraulic control circuit 56. The control states of the LU clutch 40 include a fully open state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slippage, and a fully engaged state in which the LU clutch 40 is engaged. When the LU clutch 40 is set to the fully open state, the torque converter 22 is set to the torque converter state in which the torque amplification effect can be obtained. Also, when the LU clutch 40 is set to the fully engaged state, the torque converter 22 is set to the lock-up state in which the pump impeller 22a and the turbine impeller 22b are rotated integrally.

[0023] 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 devices CB are hydraulic friction engagement devices each constituted by a multi-plate or single-plate clutch or brake pressed by a hydraulic actuator or a band brake tightened by a hydraulic actuator. The engagement devices CB have their control states such as the engaged state and the released state switched by changing their respective torque capacities, i.e., the CB torque Tcb, by the regulated CB hydraulic pressure PRcb supplied from the hydraulic control circuit 56.

[0024] The automatic transmission 24 is a stepped transmission that can form a plurality of forward gear stages and reverse gear stages with different gear ratios γ (= input rotational speed Ni / output rotational speed No) when any one of the engagement devices CB is engaged. The automatic transmission 24 is switched by the electronic control unit 90 to the gear stage formed according to the driving state such as the accelerator operation of the driver (= operator) and the vehicle speed V, that is, a plurality of gear stages are selectively formed. Also, when all of the plurality of engagement devices CB are released, it becomes neutral which cuts off power transmission. The input rotational speed Ni is the rotational speed of the input shaft 38 and is the input rotational speed of the automatic transmission 24. The input rotational speed Ni is the same value as the turbine rotational speed Nt which is the output rotational speed of the torque converter 22. The output rotational speed No is the rotational speed of the output shaft 26 and is the output rotational speed of the automatic transmission 24.

[0025] In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connection shaft 34 to the drive wheels 14 through the K0 clutch 20, the MG connection shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, and the drive shaft 32 in sequence. Also, the power output from the rotary machine MG is transmitted from the MG connection shaft 36 to the drive wheels 14 through the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, and the drive shaft 32 in sequence regardless of the control state of the K0 clutch 20.

[0026] The electric vehicle 10 includes a mechanical oil pump MOP58, an electric oil pump EOP60, a pump motor 62, etc. The MOP58 is connected to the pump impeller 22a and is rotationally driven by a driving power source (engine 12, rotary electric machine MG) to discharge the hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a dedicated motor for the EOP60 to rotationally drive the EOP60. The EOP60 is rotationally driven by the pump motor 62 to discharge the hydraulic oil OIL and can discharge the hydraulic oil OIL at any timing including when the electric vehicle 10 is stopped. The hydraulic oil OIL discharged by the MOP58 and the EOP60 is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 outputs the regulated CB hydraulic pressure PRcb, K0 hydraulic pressure PRk0, LU hydraulic pressure PRlu, etc. based on the hydraulic oil OIL discharged by the MOP58 and / or the 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 each part. The hydraulic oil OIL is accumulated in an oil sump such as an oil pan provided at the lower part of the case 18 and is pumped up by the MOP58 and / or the EOP60 and supplied to the hydraulic control circuit 56.

[0027] The electric vehicle 10 includes an electronic control unit 90 as a control device that executes various controls. The electronic control unit 90 includes a so-called microcomputer including, for example, a CPU, a RAM, a ROM, an input / output interface, etc., and the CPU performs signal processing according to a program stored in the ROM in advance while using the temporary storage function of the RAM to execute various controls of the electric vehicle 10. The electronic control unit 90 is configured to include a plurality of computers such as an engine control computer, an MG control computer, and a hydraulic control computer as necessary.

[0028] The electronic control device 90 receives various signals (such as the engine rotation speed Ne which is the rotation speed of the engine 12, the turbine rotation speed Nt which is the same as the input rotation speed Ni, the output rotation speed No corresponding to the vehicle speed V, the MG rotation speed Nmg which is the rotation speed of the rotating electrical machine MG, the accelerator opening θacc which represents the driver's output demand amount by the operation amount of the accelerator operation member 79 such as the accelerator pedal, the throttle valve opening θth which is the opening of the electronic throttle valve, the brake ON signal Bon which is a signal indicating that the brake pedal for operating the wheel brake is being operated by the driver, the battery temperature THbat, the battery charge / discharge current Ibat, and the battery voltage Vbat of the battery 54, the oil temperature THoil which is the temperature of the working oil OIL in the hydraulic control circuit 56, the signal representing the operation position POSsh of the shift lever 64 provided in the electric vehicle 10, the power switch pressing signal Spw, etc.) based on the detection values from various sensors and the like (such as 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 valve opening sensor 80, the brake switch 82, the battery sensor 84, the oil temperature sensor 86, the lever position sensor 88, the power switch 89, etc.) provided in the electric vehicle 10. The power switch 89 is a self - reset type push - button switch arranged near the driver's seat. When pressed by the driver at the start or end of driving of the electric vehicle 10, etc., the power switch pressing signal Spw is output, and it is used for various controls such as switching between the ready - OFF state where driving by the driving power sources (the engine 12, the rotating electrical machine MG) is not possible and the ready - ON state where driving is possible, and switching the ON / OFF of the power supply for each part.

[0029] The shift lever 64 is arranged near the driver's seat and is a shift operation member that is 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 operation positions POSsh, for example, a plurality of positions such as P, R, N, and D are provided, and each range of P, R, N, and D can be selected as the shift range. The P position is an operation position for selecting the parking P (parking) range in which the automatic transmission 24 is in a neutral state where power transmission is interrupted and the rotation of the output shaft 26 is mechanically blocked. The neutral state is a state in which all the engagement devices CB of the automatic transmission 24 are released. The R position is an operation position for selecting the reverse R (reverse) range in which the automatic transmission 24 is set to the reverse gear stage. The N position is an operation position for selecting the N (neutral) range in which the automatic transmission 24 is in the neutral state, similar to the P position. The D position is an operation position for selecting the forward drive D (drive) range in which, for example, a plurality of forward gear stages of the automatic transmission 24 are automatically switched according to the driving state such as the vehicle speed V and the accelerator opening θacc and the vehicle travels. The shift lever 64 may be positioned and held at each operation position POSsh of P, R, N, and D, or may be of an automatic return type that automatically returns to a predetermined home position. Also, as the shift operation member, a push button switch or the like for selecting each of the above shift ranges may be used.

[0030] From the electronic control device 90, various command signals (for example, engine control command signal Se for controlling the engine 12, MG control command signal Smg for controlling the rotating electrical machine MG, CB hydraulic pressure control command signal Scb for controlling the engagement device CB, K0 hydraulic pressure control command signal Sk0 for controlling the K0 clutch 20, LU hydraulic pressure control command signal Slu for controlling the LU clutch 40, EOP control command signal Seop for controlling the EOP 60, etc.) are output to each device (for example, engine control device 50, inverter 52, hydraulic pressure control circuit 56, motor for pump 62, etc.) provided in the electric vehicle 10. The hydraulic pressure control circuit 56 is provided with a plurality of solenoid valves that switch the oil passage and control the hydraulic pressure according to the CB hydraulic pressure control command signal Scb, the K0 hydraulic pressure control command signal Sk0, and the LU hydraulic pressure control command signal Slu.

[0031] The electronic control device 90 functionally includes a hybrid control unit 92, a shift control unit 94, an EOP abnormality detection unit 96, and a ready ON control unit 98 in order to realize various controls in the electric vehicle 10.

[0032] The hybrid control unit 92 has a function of controlling the operations of the engine 12 and the rotary electric machine MG in cooperation, and includes an engine control unit 92a that controls the engine 12 and an MG control unit 92b that controls the rotary electric machine MG. The hybrid control unit 92 calculates the driving demand amount 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 driving demand amount is, for example, the required driving torque Trdem at the drive wheels 14. The hybrid control unit 92 takes into account transmission losses, auxiliary load, the gear ratio γ of the automatic transmission 24, the torque ratio of the torque converter 22, the chargeable power Win and the dischargeable power Wout of the battery 54, etc., and obtains, for example, the required TC input torque Ttcdem which is the input torque of the torque converter 22 required to achieve the above required driving torque Trdem, and outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Smg for controlling the rotary electric machine MG so that the required TC input torque Ttcdem can be obtained. The chargeable power Win and the dischargeable power Wout of the battery 54 are calculated by the electronic control unit 90 based on, for example, the battery temperature THbat and the state of charge value SOC [%] of the battery 54. 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 amount, and can be calculated based on, for example, the battery charge and discharge current Ibat and the battery voltage Vbat.

[0033] When the output of the rotary electric machine MG alone can cover the required TC input torque Ttcdem, the hybrid control unit 92 sets it to the BEV (Battery Electric Vehicle) driving mode, in which the rotary electric machine MG is driven only by the power from the battery 54 to run. In the BEV driving mode, the K0 clutch 20 is released to stop the engine 12, and BEV driving is performed using only the rotary electric machine MG as the driving power source. In this BEV driving mode, the MG torque Tmg is controlled to achieve the required TC input torque Ttcdem. On the other hand, when the output of at least the engine 12 is not used, the required TC input torque Ttcdem cannot be covered, the hybrid control unit 92 sets it to the HEV (Hybrid Electric Vehicle) driving mode, which is the engine driving mode. In the HEV driving mode, the K0 clutch 20 is engaged, and engine driving, that is, HEV driving, is performed using at least the engine 12 as the driving power source. In this HEV driving mode, the engine torque Te is controlled to achieve all or part of the required TC input torque Ttcdem, and the MG torque Tmg is controlled to compensate for the torque shortage of the engine torque Te with respect to the required TC input torque Ttcdem. On the other hand, even when the output of the rotary electric machine MG alone can cover the required TC input torque Ttcdem, the hybrid control unit 92 establishes the HEV driving mode when warm-up of the engine 12 or the like is necessary. Thus, the hybrid control unit 92 automatically stops the engine 12 during HEV driving, restarts the engine 12 after the engine stop, starts the engine 12 during BEV driving, automatically stops the engine 12 during parking, or starts the engine 12 based on the required TC input torque Ttcdem or the like, and switches between the BEV driving mode and the HEV driving mode.

[0034] When the D range is selected, the shift control unit 94 performs shift determination of the automatic transmission 24 using a shift map or the like determined in advance with driving states such as the vehicle speed V and the accelerator opening θacc as variables, and outputs a CB hydraulic pressure control command signal Scb for automatically switching a plurality of forward gear stages of the automatic transmission 24 to the hydraulic pressure control circuit 56 as necessary to execute automatic shift control. Further, when the shift lever 64 or a manual shift operation member provided near the driver's seat is operated by the driver and a shift instruction signal is supplied, manual shift control for switching the forward gear stage of the automatic transmission 24 according to the shift instruction is executed.

[0035] The shift control unit 94 also executes garage control for switching the shift range of the automatic transmission 24 according to the switched operation position POSsh when the shift lever 64 is operated and the operation position POSsh is switched. The garage control executes reverse range switching for switching the automatic transmission 24 from one of the D range and the R range to the other according to the reverse shift operation when a reverse shift operation for switching the shift lever 64 from one of the D position and the R position to the other is performed, and also executes various range switching for switching the shift range between the non-driving ranges of the P range and the N range and the driving ranges of the D range and the R range.

[0036] The EOP abnormality detection unit 96 detects a malfunction of the EOP 60 including an abnormality in the electrical system due to a disconnection of the pump motor 62 or the like, and can determine whether or not there is an EOP abnormality based on, for example, the rotational speed of the pump motor 62 with respect to the EOP control command signal Seop, the hydraulic pressure of each part, the operating state of the hydraulic actuator, and the like.

[0037] When the Ready ON control unit 98 performs a Ready ON operation to enable driving by a driving power source in response to a driving request in the Ready OFF state where both the engine 12 and the rotating machine MG, which are driving power sources, are stopped and driving by the driving power source is impossible, it executes Ready ON control to set the state to Ready ON according to steps S1 to S6 of the flowchart in FIG. 2 (hereinafter, the steps are omitted and simply referred to as S1 to S6). The driving request is a request to drive the electric vehicle 10, such as an accelerator ON operation in which the driver operates the accelerator operation member 79. In the Ready ON state, it becomes possible to perform driving by the driving power source according to the driving request. The Ready OFF state where driving by the driving power source is impossible is, for example, a power OFF state in which most of the power sources of the electric vehicle 10 are turned off, or an accessory ON state in which power is supplied to accessory products such as audio equipment and navigation devices.

[0038] In S1 of FIG. 2, it is determined whether a Ready ON operation has been performed in the Ready OFF state. If a Ready ON operation is detected, S2 and subsequent steps are executed, but if a Ready ON operation cannot be detected, the process ends as it is. The Ready ON operation to enable driving by the driving power source is, for example, that with the operation position POSsh of the shift lever 64 being P, the brake pedal being depressed to supply a brake ON signal Bon from the brake switch 82, and the power switch 89 being pressed to supply a power switch pressing signal Spw.

[0039] When the READY ON operation is detected and the determination in S1 is YES (affirmative), S2 is executed to determine whether it is during pump drive restriction where the drive of the EOP 60 is restricted. During pump drive restriction, in this embodiment, it is the case where the oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 56, is equal to or higher than a predetermined high oil temperature threshold thoils, or when the EOP abnormality detection unit 96 determines an EOP abnormality. If either one of these conditions is satisfied, it is determined to be during pump drive restriction and S3 is executed. On the other hand, if neither condition is met, S5 is executed. As pump drive restriction, only an EOP abnormality may be defined, or other requirements may be defined, such as when the drive of the EOP 60 is restricted due to output limitation or abnormality of the battery 54.

[0040] In S3, since the drive of the EOP 60 is restricted and the K0 clutch 20 cannot be engaged by the hydraulic pressure from the EOP 60, the engine 12 is started by push start control. The push start control is a control that rotates the rotating machine MG to engage the K0 clutch 20 by the hydraulic pressure output from the MOP 58 and cranks and starts the engine 12 by the engagement control of the K0 clutch 20. For example, various controls are executed via the engine control unit 92a, the MG control unit 92b, the shift control unit 94 involved in hydraulic control, etc. Specifically, the rotating machine MG is rotationally driven at a rotational speed equal to or higher than a predetermined crank rotational speed Necrank at which the engine 12 can be started, and the K0 clutch 20 is slip engaged and controlled by the hydraulic pressure output from the MOP 58 rotationally driven by the rotating machine MG to increase the engine rotational speed Ne. When the engine rotational speed Ne reaches the crank rotational speed Necrank, the K0 clutch 20 is fully engaged to connect the engine 12 to the MG connecting shaft 36, and in this state, starting processes such as fuel injection and ignition are performed to start the engine 12. When the engine 12 reaches a complete explosion state where it rotates independently, a determination of start completion is made in S4. For example, the engine rotational speed Ne is maintained at an idle rotational speed or the like, and an HEV READY ON state in which HEV travel using the engine 12 as a driving power source is possible is set. This HEV READY ON state can also be referred to as an engine running READY ON state.

[0041] In S5, which is executed when the determination of S2 is NO (negative), HEV Ready ON in which the engine 12 is used as a driving power source to run according to normal selection determination conditions or BEV Ready ON in which the motor MG is used as a driving power source to run is selected. The selection determination conditions are determined based on, for example, the presence or absence of an engine start request due to the engine 12's warm air requirement or the battery 54's charging requirement. When there is an engine start request, HEV Ready ON is selected, and when there is no engine start request, BEV Ready ON is selected. Then, when HEV Ready ON is selected, the engine 12 is started by MG start control. The MG start control drives the EOP 60 to generate hydraulic pressure to engage the K0 clutch 20, and then raises the rotational speed Nmg of the motor MG and raises the engine rotational speed Ne to perform cranking. When the engine rotational speed Ne reaches the crank rotational speed Necrank, start-up processes such as fuel injection and ignition are performed to start the engine 12. This MG start control corresponds to motor start control and executes various controls via, for example, the engine control unit 92a, the MG control unit 92b, and the shift control unit 94 involved in hydraulic control. Then, when the engine 12 reaches a complete explosion state where it rotates independently, a determination of start completion is made in S6. For example, the engine rotational speed Ne is maintained at the idle rotational speed or the like, and the HEV Ready ON state in which HEV running with the engine 12 as a driving power source is possible is set. When BEV Ready ON is selected in S5, S6 may be immediately executed to set the BEV Ready ON state in which BEV running with the motor MG as a driving power source is possible. This BEV Ready ON state can also be referred to as the motor running Ready ON state. Note that HEV Ready ON may be selected due to factors other than the engine start request, and the selection determination conditions can be arbitrarily determined.

[0042] According to the Ready ON control unit 98 provided in the electronic control unit 90 of the electric vehicle 10 of this embodiment as described above, when a Ready ON operation is performed in the Ready OFF state, during pump drive restriction where the drive of the EOP 60 is restricted, by rotationally driving the rotary machine MG, the K0 clutch 20 is engaged by the hydraulic pressure output from the MOP 58, and push start control for cranking the engine 12 is performed by the engagement control of the K0 clutch 20 to start the engine 12, and a HEV Ready ON state enabling HEV travel with the engine 12 as a driving power source is set, so that the driving performance can be appropriately ensured such that the engine can start even during pump drive restriction.

[0043] Also, when a Ready ON operation is performed in the Ready OFF state and it is not during pump drive restriction, after driving the EOP 60 to engage the K0 clutch 20, MG start control for cranking the engine 12 while increasing the rotational speed Nmg of the rotary machine MG is performed to start the engine 12, and a HEV Ready ON state enabling driving travel with the engine 12 as a driving power source is set, so that the engine 12 can be started while suppressing the load on the K0 clutch 20 and the driving performance can be appropriately ensured.

[0044] Also, when a Ready ON operation is performed in the Ready OFF state, during pump drive restriction, the engine 12 is immediately started by push start control to set a HEV Ready ON state enabling HEV travel, while when it is not during pump drive restriction, whether to start the engine 12 by MG start control to set a HEV Ready ON state enabling HEV travel with the engine 12 as a driving power source or to set a BEV Ready ON state enabling BEV travel with the rotary machine MG as a driving power source is selected. Therefore, regardless of whether it is during pump drive restriction or not, the driving performance can be appropriately ensured by starting the engine. Also, according to the MG start control, since the engine 12 can be promptly started in response to a start request for the engine 12 even when the vehicle is stopped, the start of the engine 12 can be suppressed while ensuring the driving force responsiveness, thereby improving the fuel efficiency.

[0045] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, this is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Description of Reference Numerals

[0046] 10: Hybrid electric vehicle 12: Engine (driving force source) 20: K0 clutch (engine connection / disconnection device) 58: MOP (mechanical oil pump) 60: EOP (electric oil pump) 62: Electric motor for pump 90: Electronic control unit (control unit) 98: Ready ON control unit MG: Rotating machine (electric motor, driving force source)

Claims

【Claim 1】 An engine and an electric motor used as a driving power source, An engine disconnecting device which is a hydraulic friction engagement device that connects and disconnects power transmission between the engine and the electric motor, A mechanical oil pump that outputs hydraulic pressure used when engaging the engine disconnecting device by being rotationally driven by at least the electric motor of the driving power source, An electric oil pump that outputs hydraulic pressure used when engaging the engine disconnecting device by being rotationally driven by a pump electric motor, In a control device for a hybrid electric vehicle comprising: When a Ready ON operation is performed to enable driving by the driving power source in a Ready OFF state where the driving power source is stopped and driving by the driving power source is impossible, it is determined whether it is a pump drive restriction time when the drive of the electric oil pump is restricted. At the pump drive restriction time, the engine is cranked and started by push start control in which the engine disconnecting device is engaged by the hydraulic pressure output from the mechanical oil pump by rotationally driving the electric motor, and the rotational speed of the engine is increased by the engagement control of the engine disconnecting device. It has a Ready ON control unit that sets a Ready ON state in which driving is possible with the engine as a driving power source. When the Ready ON operation is performed in the Ready OFF state and it is not the pump drive restriction time, the Ready ON control unit drives the electric oil pump to engage the engine disconnecting device, and then cranks and starts the engine by electric motor start control in which the rotational speed of the engine is increased while increasing the rotational speed of the electric motor, and sets a Ready ON state in which driving is possible with the engine as a driving power source. When the Ready ON operation is performed in the Ready OFF state, the Ready ON control unit immediately starts the engine by the push start control at the pump drive restriction time to set a Ready ON state in which driving is possible with the engine as a driving power source. On the other hand, when it is not the pump drive restriction time, it is selected whether to start the engine by the electric motor start control to set a Ready ON state in which driving is possible with the engine as a driving power source, or to set a Ready ON state in which driving is possible with the electric motor as a driving power source without starting the engine. A control device for a hybrid electric vehicle, characterized by the above.

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