Vehicle control device

Abstract

To restrain deterioration in the starting performance of an engine.SOLUTION: An engine start request according to a learning requirement is outputted when a predetermined learning permission condition is satisfied by a clutch control unit that executes learning control for correcting a relation expressing a correlation between a torque capacity of a clutch and a starting command value based on a numerical value, i.e., a learning parameter, which indicates a degree of a phenomenon caused by a variation of a torque capacity of the clutch relative to the starting command value. The learning control is executed at the start of an engine that is associated with the engine start request according to the learning requirement. Therefore, the engine is started in a state suitable for the learning control, a change other than a change resulting from the variation of the torque capacity of the clutch is made less likely to be included in the learning parameters, and a decrease in learning accuracy is restrained. Accordingly, a decrease in the starting performance of the engine can be restrained.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle having a clutch provided between an engine and an electric motor. [Background technology]

[0002] A well-known vehicle control device includes an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to transmit power, a clutch provided in the power transmission path between the engine and the electric motor, and a hydraulic control circuit that supplies a regulated hydraulic pressure used to switch the control state of the clutch. Patent Document 1 discloses an example of such a vehicle control device. Patent Document 1 discloses that variations in the torque capacity of a clutch relative to a clutch command value occur due to individual differences in the clutch and aging, and that, in response to these variations, learning control is performed to correct the discrepancy between the clutch command value and the torque capacity based on changes in the rotational speed of the electric motor at engine start. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-58485 Summary of the Invention [Problem to be solved by the invention]

[0004] However, during the engine startup transition, changes in the accelerator pedal position, etc., can cause changes in the rotation speed of the electric motor. Therefore, the learning parameters used for learning control of, for example, changes in the rotation speed of the electric motor, may include changes other than those caused by variations in the torque capacity of the clutch, which may reduce the learning accuracy. This may result in a deterioration in the engine startup performance. Note that the learning parameters are numerical values ​​that represent the degree of the phenomenon caused by variations in the torque capacity of the clutch relative to the clutch command value, for example.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a vehicle control device that can suppress a decrease in engine starting performance. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is a control device for a vehicle including: (a) an engine; an electric motor connected to a power transmission path between the engine and drive wheels so as to be capable of transmitting power; a clutch provided in the power transmission path between the engine and the electric motor; and a hydraulic control circuit that supplies adjusted hydraulic pressure used to switch a control state of the clutch, (b) an engine control unit that determines whether or not an engine start request exists, and controls the engine so as to start the engine when it determines that the engine start request exists; and (c) when starting the engine, outputs a start command value that adjusts the hydraulic pressure by the hydraulic control circuit so as to switch the control state of the clutch from a released state to an engaged state, and (d) an electric motor control unit that, when starting the engine, controls the electric motor so that the electric motor outputs a cranking torque necessary for cranking to increase the rotation speed of the engine, the cranking torque being transmitted via the clutch; and (e) when a predetermined learning permission condition is met, the clutch control unit outputs an engine start request based on a learning requirement, which is the engine start request that requires the execution of the learning control, and executes the learning control when starting the engine in accordance with the engine start request based on the learning requirement. (f) the predetermined learning permission condition includes a condition that predetermined learning enablement conditions, including a condition that the vehicle is in a stopped state, are met consecutively for a start request delay time; and (g) the clutch control unit sets the start request delay time based on each of a plurality of operating positions of a shift operating member operated by a driver, which corresponds to a plurality of shift positions of a power transmission device that transmits power from a power source including the engine and the electric motor to the drive wheels. The reason is that.

[0008] Also, 2 The invention is 1In the vehicle control device described in the invention, the clutch control unit sets the start request delay time to a longer value when the operating position is a driving operating position that selects a driving position in which power transmission in the power transmission device is possible, compared to when the operating position is a non-driving operating position that selects a non-driving position in which power transmission in the power transmission device is cut off.

[0009] Also, 3 The invention of the present invention is the first invention Or the second invention In the vehicle control device described above, the predetermined learning permission condition includes a condition that the engine, for which the learning control has not been performed, has been started a predetermined number of times or more in succession.

[0010] Also, 4 The invention is 3 In the vehicle control device according to the invention, the clutch control unit sets the predetermined number of starts to a larger value as the correction by the learning control progresses.

[0011] Also, 5 The present invention is the first to third inventions. 4 In the vehicle control device described in any one of the inventions, the clutch control unit maintains the operating state of the engine using the engine control unit until a predetermined operating time has elapsed from the time when the engine start-up in response to the engine start request based on the learning requirements is completed. [Effects of the Invention]

[0012] According to the first aspect of the present invention, the clutch control unit executes learning control to correct the correlation between the torque capacity of the clutch and the starting command value based on a learning parameter, i.e., a value that indicates the degree of a phenomenon caused by variations in the torque capacity of the clutch relative to the starting command value. When a predetermined learning permission condition is met, an engine start request based on the learning requirement is output, and learning control is executed when the engine is started in response to the engine start request based on the learning requirement. This allows the engine to be started in a state suitable for learning control, making it difficult for changes other than those caused by variations in the torque capacity of the clutch to be included in the learning parameter, thereby suppressing a decrease in learning accuracy. As a result, a decrease in engine starting performance can be suppressed.

[0013] In addition, the above 1 According to the invention, the predetermined learning permission conditions include a condition that predetermined learning enablement conditions, including a condition that the vehicle is in a stopped state, are met consecutively for the start request delay time, and the clutch control unit sets the start request delay time based on each of a plurality of operating positions of the shift operating member, so that the engine is started in a state suitable for learning control and the discomfort caused by starting the engine when the vehicle is stopped can be suppressed.

[0014] In addition, the above 2 According to the invention, the clutch control unit sets the start request delay time to a longer value when the operating position is a driving operating position compared to when the operating position is a non-driving operating position, so that engine start-up immediately after stopping is suppressed, or it is possible to expect a switching operation from a driving operating position to a non-driving operating position before the output of an engine start request is determined.

[0015] In addition, the above 3 According to the invention, the predetermined learning permission condition includes a condition that the engine has been started consecutively for a predetermined number of times or more without learning control being performed, so that engine start-up in response to an engine start request based on learning requirements is suppressed, deterioration of fuel economy is suppressed, and exhaust gas requirements are taken into consideration.

[0016] In addition, the above 4 According to the invention, the clutch control unit sets the specified number of starts to a larger value as the correction through learning control progresses, thereby further suppressing deterioration in fuel efficiency and taking exhaust gas requirements into consideration.

[0017] In addition, the above 5 According to the invention, the clutch control unit maintains the engine operating state until a predetermined operating time has elapsed from the time when the engine start-up in response to the engine start-up request based on the learning requirements is completed, thereby suppressing the busy feeling caused by the engine being stopped immediately when the engine start-up in response to the engine start-up request based on the learning requirements is completed. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and control systems for various controls in the vehicle. [Figure 2] FIG. 4 is a diagram showing an example of a time chart when engine start control is executed. [Figure 3] 1 is a flowchart illustrating the main control operations of the electronic control device, particularly the clutch control unit (CLT_ECU), and is a flowchart illustrating the control operations for suppressing a decrease in engine starting performance. [Figure 4] 10 is a flowchart illustrating a control operation for progressing correction by startup K0 learning control in a cooperative control system startup type, and is a subroutine corresponding to step S60a in the flowchart of FIG. [Figure 5] 10 is a flowchart illustrating a control operation for progressing correction by startup K0 learning control in a STEP control system startup type, and is a subroutine corresponding to step S70a in the flowchart of FIG. [Figure 6]10 is a flowchart illustrating a control operation for further advancing correction by the start K0 learning control, and is a subroutine corresponding to step S80a in the flowchart of FIG. [Figure 7] This is a flowchart explaining the main control operations of the electronic control device, particularly the engine control unit (ENG_ECU), and is a flowchart explaining the control operations for suppressing a decrease in the engine starting performance, and is executed together with the flowchart of Figure 3. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0020] Fig. 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates the main parts of the control functions and control systems for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG that function as a power source SP. The vehicle 10 also has drive wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14.

[0021] The engine 12 is a known internal combustion engine such as a gasoline engine, a diesel engine, etc. An electronic control device 90 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc., provided in the vehicle 10, thereby controlling the engine torque Te, which is the output torque of the engine 12.

[0022] The electric motor MG is a rotating electric machine, a so-called motor generator, that functions as a motor that generates mechanical power from electric power and as a generator that generates electric power from mechanical power. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The inverter 52 is controlled by an electronic control device 90 (described later), thereby controlling the MG torque Tm, which is the output torque of the electric motor MG. For example, when the rotation direction of the electric motor MG is forward, which is the same as the rotation direction of the engine 12 when it is operating, the MG torque Tm is a power torque when it is a positive torque on the acceleration side, and a regenerative torque when it is a negative torque on the deceleration side. Specifically, the electric motor MG generates power using electric power supplied from the battery 54. The electric motor MG also generates electric power using the power of the engine 12 and the driven force input from the drive wheels 14. The battery 54 is charged with the electric power generated by the electric motor MG. The term "electric power" also refers to electrical energy unless otherwise specified. The term "motive power" also refers to driving force, torque, and force unless otherwise specified.

[0023] The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, housed within a case 18, which is a non-rotating member attached to the vehicle body. The K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in a power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22 and is interposed in the power transmission path between the torque converter 22 and the drive wheels 14. The automatic transmission 24 is a transmission provided between the electric motor MG and the drive wheels 14 in the power transmission path between the engine 12 and the drive wheels 14. The power transmission device 16 also 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, a pair of drive shafts 32 connected to the differential gear 30, and the like. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like.

[0024] The electric motor MG is connected to the electric motor connecting shaft 36 in the case 18 so as to be able to transmit power. In other words, the electric motor MG is connected to the power transmission path between the engine 12 and the drive wheels 14, particularly to the power transmission path between the K0 clutch 20 and the torque converter 22. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be able to transmit power without passing through the K0 clutch 20.

[0025] The torque converter 22 includes a pump wheel 22a connected to the electric motor connecting shaft 36, and a turbine wheel 22b connected to a transmission input shaft 38, which is an input rotating member of the automatic transmission 24. The torque converter 22 is a fluid transmission device that transmits power from the power source SP from the electric motor connecting shaft 36 to the transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 as a direct-coupled clutch that connects the pump wheel 22a and the turbine wheel 22b, i.e., that connects the electric motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a known lock-up clutch.

[0026] The LU clutch 40 switches its operating state, i.e., its control state, by changing the LU torque Tlu, which is the torque capacity of the LU clutch 40, using the LU oil pressure PRlu, which is a regulated oil pressure supplied from a hydraulic control circuit 56 provided in the vehicle 10. The control states of the LU clutch 40 include a released state in which the LU clutch 40 is completely released, a slip state in which the LU clutch 40 is engaged with slippage, and an engaged state in which the LU clutch 40 is completely engaged. When the LU clutch 40 is in the released state, the torque converter 22 is in a torque converter state in which a torque amplification effect is obtained. When the LU clutch 40 is in the engaged state, the torque converter 22 is in a lock-up state in which the pump wheel 22a and the turbine wheel 22b rotate together.

[0027] The automatic transmission 24 is a known planetary gear automatic transmission that includes, for example, one or more planetary gear devices (not shown) and a plurality of engagement devices CB. The engagement devices CB are, for example, known hydraulic friction engagement devices. Each engagement device CB has its torque capacity (CB torque Tcb) changed by a CB oil pressure PRcb, which is a regulated oil pressure supplied from a hydraulic control circuit 56, thereby switching its control state between an engaged state, a disengaged state, and the like.

[0028] The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also referred to as gear stages) with different speed ratios (also referred to as gear ratios) γat (=AT input rotation speed Ni / AT output rotation speed No) is established by engaging one of the engagement devices CB. The automatic transmission 24 switches between gear stages established in accordance with the driver's accelerator operation, vehicle speed V, etc. by an electronic control device 90, which will be described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38, and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is equal to the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed in terms of the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26, and is the output rotation speed of the automatic transmission 24.

[0029] The K0 clutch 20 is a hydraulic friction engagement device configured, for example, with a multi-plate or single-plate clutch. The K0 clutch 20 switches between control states such as an engaged state, a slip state, and a released state by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, using the K0 oil pressure PRk0, which is the adjusted oil pressure supplied from the hydraulic control circuit 56.

[0030] In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected to each other so that power can be transmitted between them. On the other hand, when the K0 clutch 20 is disengaged, power transmission between the engine 12 and the torque converter 22 is interrupted. Because the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that connects and disconnects the engine 12 from the electric motor MG.

[0031] 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 connecting shaft 34 to the drive wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order. Similarly, regardless of the control state of the K0 clutch 20, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the drive wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order. In this way, the power transmission device 16 transmits the power from the power source SP to the drive wheels 14.

[0032] The vehicle 10 is equipped with a MOP 58 which is a mechanical oil pump, an EOP 60 which is an electric oil pump, a pump motor 62, etc. The MOP 58 is connected to the pump impeller 22a and is driven to rotate by a power source SP to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for driving the EOP 60 to rotate. The EOP 60 is driven to rotate by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies the LU hydraulic pressure PRlu, the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, etc., which are each adjusted based on the hydraulic oil OIL discharged by the MOP 58 and / or the EOP 60.

[0033] The vehicle 10 further includes an electronic control device 90 that includes a control device for the vehicle 10. The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing in accordance with programs stored in the ROM in advance while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, clutch control, etc. as necessary.

[0034] For example, the electronic control device 90 may include an engine control computer ENG_ECU that functions as an engine control unit 92a (described later), an electric motor control computer MG_ECU that functions as an electric motor control unit 92b (described later), and a clutch control computer CLT_ECU that functions as a clutch control unit 94. Various signals are transmitted between the computers via a predetermined communication system, for example, a CAN (Controller Area Network) communication system.

[0035] The electronic control device 90 receives various signals based on detected values ​​from various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 70, a turbine rotation speed sensor 72, an output rotation speed sensor 74, an MG rotation speed sensor 76, an accelerator opening sensor 78, a throttle valve opening sensor 80, a brake switch 82, a battery sensor 84, an oil temperature sensor 86, a shift position sensor 88, etc.) and outputs various signals (for example, an engine rotation speed Ne which is the rotation speed of the engine 12 and a crank angle Acr which indicates the rotation position of the crankshaft of the engine 12, a turbine rotation speed Nt which is the same value as the AT input rotation speed Ni, an AT output rotation speed No corresponding to the vehicle speed V, a rotation speed of the electric motor MG, etc.). The vehicle 10 is supplied with the following signals: MG rotation speed Nm, which is the rotation speed; accelerator opening θacc, which is the amount of accelerator operation by the driver indicating the magnitude of the driver's acceleration operation; throttle valve opening θth, which is the opening of the electronic throttle valve; brake-on signal Bon, which is a signal indicating the state in which the brake pedal for operating the wheel brakes is being operated by the driver; battery temperature THbat, battery charge / discharge current Ibat, and battery voltage Vbat of the battery 54; hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 56; and shift operation position POSsh, which indicates the operation position (=operation position) of a shift lever 64 provided in the vehicle 10.

[0036] The shift lever 64 is a shift operation member that is operated by the driver to one of a plurality of shift operation positions POSsh. The shift operation position POSsh is an operation position of the shift lever 64 for selecting a shift position (=shift position) of the power transmission device 16, particularly the automatic transmission 24. The shift operation position POSsh includes, for example, P, R, N, and D operation positions as a plurality of operation positions of the shift lever 64 that correspond to the P, R, N, and D positions as a plurality of shift positions of the automatic transmission 24.

[0037] The P operating position is a parking operating position for selecting a parking position (=P position) that is a parking position of the automatic transmission 24. The P position of the automatic transmission 24 is a shift position of the automatic transmission 24 in which the automatic transmission 24 is in a neutral state and rotation of the transmission output shaft 26 is mechanically prevented. The neutral state of the automatic transmission 24 is a state in which the automatic transmission 24 is unable to transmit driving force, and is achieved, for example, by disengaging both of the engagement devices CB and cutting off power transmission in the automatic transmission 24. The state in which rotation of the transmission output shaft 26 is mechanically prevented is a parking lock state in which the transmission output shaft 26 is fixed so as not to rotate by a known parking lock mechanism provided in the vehicle 10. The R operating position is a reverse driving operating position for selecting a reverse driving position (=R position) that is a reverse driving position of the automatic transmission 24. The R position of the automatic transmission 24 is a shift position of the automatic transmission 24 that enables the vehicle 10 to travel backward. The N operating position is a neutral operating position that selects the neutral position (=N position) that is the neutral position of the automatic transmission 24. The N position of the automatic transmission 24 is a shift position of the automatic transmission 24 in which the automatic transmission 24 is in a neutral state. The D operating position is a forward travel operating position that selects the forward travel position (=D position) that is the forward travel position of the automatic transmission 24. The D position of the automatic transmission 24 is a shift position of the automatic transmission 24 that executes automatic shift control of the automatic transmission 24 and enables the vehicle 10 to travel forward. The P position and N position of the automatic transmission 24 are non-travel positions of the automatic transmission 24 in which the automatic transmission 24 is unable to transmit driving force, and are non-travel positions in which power transmission in the power transmission device 16 is interrupted. The P operating position and N operating position of the shift operating position POSsh are non-driving operating positions that select a non-driving position of the automatic transmission 24. The R position and D position of the automatic transmission 24 are driving positions of the automatic transmission 24 that enable the automatic transmission 24 to transmit driving force, and are driving positions that enable power transmission in the power transmission device 16.The R operation position and the D operation position of the shift operation position POSsh are driving operation positions that select the driving position of the automatic transmission 24.

[0038] The electronic control device 90 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, an LU hydraulic control command signal Slu for controlling the LU clutch 40, an EOP control command signal Seop for controlling the EOP 60, etc.) to each device provided in the vehicle 10 (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.).

[0039] Each hydraulic control command signal S will be described using the K0 hydraulic control command signal Sk0 as an example. The electronic control device 90 calculates a K0 hydraulic pressure command value Spk0, which is a hydraulic pressure command value for causing the hydraulic control circuit 56 to supply the regulated K0 hydraulic pressure PRk0, as a command value for the K0 hydraulic pressure PRk0. The electronic control device 90 converts the K0 hydraulic pressure command value Spk0 into a K0 command current value Sik0 for driving the K0 solenoid SLk0 provided in the hydraulic control circuit 56. The K0 solenoid SLk0 is a solenoid valve for the K0 clutch 20 that outputs the K0 hydraulic pressure PRk0. The K0 command current value Sik0 is a command current for a solenoid driver, which is a drive circuit provided in the electronic control device 90 that drives the K0 solenoid SLk0. The K0 hydraulic pressure control command signal Sk0 is a drive current or drive voltage for the solenoid driver to drive the K0 solenoid SLk0 based on the K0 command current value Sik0. That is, the K0 hydraulic pressure command value Spk0 is converted into a K0 hydraulic pressure control command signal Sk0 and output to the hydraulic control circuit 56. In this embodiment, for convenience, the K0 hydraulic pressure command value Spk0 and the K0 hydraulic pressure control command signal Sk0 are treated as the same.

[0040] The electronic control unit 90 includes a power source control means, i.e., a power source control section 92, and a clutch control means, i.e., a clutch control section 94, in order to realize various controls in the vehicle 10.

[0041] The power source control unit 92 includes a function as engine control means, i.e., engine control unit 92a, that controls the operation of the engine 12, and a function as electric motor control means, i.e., electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and is a hybrid control means, i.e., a hybrid control unit, that performs hybrid drive control using the engine 12 and the electric motor MG using these control functions.

[0042] The power source control unit 92 calculates a drive demand DEM from the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a drive demand map. The drive demand map is a relationship that is determined experimentally or by design and stored in advance, i.e., a predetermined relationship. The drive demand DEM is, for example, a required drive torque Trdem at the drive wheels 14. The required drive torque Trdem [Nm] can be viewed from another perspective as a required drive power Prdem [W] at the vehicle speed V at that time. The drive demand DEM can also be, for example, a required drive force Frdem [N] at the drive wheels 14 or a required AT output torque at the transmission output shaft 26. In calculating the drive demand DEM, an AT output rotation speed No or the like can be used instead of the vehicle speed V. The power source control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration transmission loss, auxiliary load, the gear ratio γat of the automatic transmission 24, etc. Note that in controls other than controlling the output of the vehicle 10, such as the driving torque Tr, the required driving amount DEM can simply be, for example, the accelerator opening θacc or the throttle valve opening θth.

[0043] When the required drive torque Trdem can be satisfied solely by the output of the electric motor MG, the power source control unit 92 sets the drive mode for driving the vehicle 10 to BEV drive mode. The BEV drive mode is a motor drive mode that enables motor driving (=BEV driving) using only the electric motor MG as the power source SP when the K0 clutch 20 is disengaged. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the power source control unit 92 sets the drive mode to engine drive mode, i.e., HEV drive mode. The HEV drive mode is a hybrid drive mode that enables engine driving (=HEV driving) using at least the engine 12 as the power source SP when the K0 clutch 20 is engaged. On the other hand, even when the required drive torque Trdem can be satisfied solely by the output of the electric motor MG, the power source control unit 92 establishes the HEV drive mode when, for example, the battery 54 needs to be charged or the engine 12 needs to be warmed up.

[0044] The power source control unit 92, particularly the engine control unit 92a, determines whether or not there is an engine start request REQst to switch the control state of the engine 12 from a stopped state to an operating state. For example, in the BEV drive mode, the engine control unit 92a determines whether or not there is an engine start request REQst based on whether or not the required drive torque Trdem has increased beyond a range that can be covered by the output of the electric motor MG alone, whether or not the engine 12 and the like need to be warmed up, or whether or not the battery 54 needs to be charged.

[0045] When the power source control unit 92 determines that an engine start request REQst has been issued, the clutch control unit 94 controls the K0 clutch 20 to execute start control of the engine 12. For example, the clutch control unit 94 outputs a K0 hydraulic pressure command value Spk0 for controlling the K0 clutch 20 from a released state toward an engaged state so as to obtain a K0 torque Tk0 for transmitting the cranking torque Tcr to the engine 12. That is, when starting the engine 12, the clutch control unit 94 outputs a start-up K0 hydraulic pressure command value Spk0 as a start-up command value for adjusting the K0 hydraulic pressure PRk0 by the hydraulic control circuit 56 so as to switch the control state of the K0 clutch 20 from a released state to an engaged state. The cranking torque Tcr is a torque required for cranking the engine 12 to increase the engine rotation speed Ne. In this embodiment, the start-up K0 hydraulic pressure command value Spk0 is referred to as a start-up K0 command value Spk0st.

[0046] When the power source control unit 92 determines that there is an engine start request REQst, it controls the engine 12 and the electric motor MG to execute start control of the engine 12. For example, the electric motor control unit 92b outputs an MG control command signal Sm to the inverter 52 in response to switching of the K0 clutch 20 to the engaged state, so that the electric motor MG outputs a cranking torque Tcr. That is, when starting the engine 12, the electric motor control unit 92b outputs an MG control command signal Sm to the inverter 52 to control the electric motor MG so that the electric motor MG outputs the cranking torque Tcr transmitted via the K0 clutch 20, i.e., so that the MG torque Tm is increased by the cranking torque Tcr. Furthermore, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 in response to cranking of the engine 12, so that fuel supply, engine ignition, and the like are started. That is, when starting the engine 12, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 for controlling the engine 12 so that the engine 12 starts operating in conjunction with switching the K0 clutch 20 to the engaged state, i.e., cranking of the engine 12. The engine control unit 92a outputs an engine control command signal Se to the engine control device 50 for outputting an engine torque Te so that the engine 12 reaches a state where self-sustaining rotation due to the explosion of the engine 12 becomes stable after the initial explosion when ignition of the engine 12 starts, i.e., a state where the engine 12 reaches a complete explosion. In this way, when it is determined that there is an engine start request REQst, the engine control unit 92a controls the engine 12 so that the engine 12 starts operating.

[0047] When cranking the engine 12, a reaction torque is generated due to engagement of the K0 clutch 20. During BEV driving, this reaction torque causes a drop in the drive torque Tr due to the inertia of the engine 12 and other components during engine start. Therefore, the MG torque Tm that is increased toward the cranking torque Tcr when starting the engine 12 is the MG torque Tm that cancels out this reaction torque and compensates for this reaction torque, i.e., the MG torque Tm for reaction compensation. The cranking torque Tcr is the K0 torque Tk0 required to crank the engine 12, and is the MG torque Tm required to crank the engine 12 that flows from the electric motor MG side to the engine 12 side via the K0 clutch 20. The cranking torque Tcr is, for example, a constant torque that is predetermined based on, for example, the specifications of the engine 12, the starting method of the engine 12, etc.

[0048] The power source control unit 92, particularly the engine control unit 92a, determines whether there is an engine stop request, which is a request to stop the engine 12 by switching the control state of the engine 12 from a running state to a stopped state. For example, in the HEV drive mode, the engine control unit 92a determines whether there is an engine stop request based on whether the required drive torque Trdem is within a range that can be covered by the output of the electric motor MG alone, whether warming up the engine 12 and the like is unnecessary, whether charging the battery 54 is unnecessary, and so on.

[0049] When the engine control unit 92a determines that there is an engine stop request, it outputs an engine control command signal Se to the engine control device 50 to gradually reduce the engine torque Te. After that, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 to execute a fuel cut that stops the supply of fuel to the engine 12 after the clutch control unit 94 switches the K0 clutch 20 to the released state.

[0050] The clutch control unit 94 determines whether to shift the automatic transmission 24 using, for example, a shift map, which is a predetermined relationship, and outputs a CB hydraulic control command signal Scb to the hydraulic control circuit 56 as needed to execute shift control of the automatic transmission 24. The shift map is a predetermined relationship having shift lines on a two-dimensional coordinate system using, for example, vehicle speed V and required drive torque Trdem as variables, for determining whether to shift the automatic transmission 24. In the shift map, the AT output rotation speed No or the like may be used instead of the vehicle speed V, and the required drive force Frdem, accelerator opening θacc, throttle valve opening θth or the like may be used instead of the required drive torque Trdem.

[0051] FIG. 2 is a diagram showing an example of a time chart when start control of the engine 12 is executed. In FIG. 2, time t1 indicates the time when start control of the engine 12 is initiated, for example, when the driver further depresses the accelerator pedal during BEV driving, and it is determined that an engine start request REQst has been issued. After start control of the engine 12 is initiated, packing control of the K0 clutch 20, i.e., K0 packing control, is executed (see time t1-t2). The K0 packing control is a control that closes the pack clearance of the friction plates of the K0 clutch 20. In the K0 packing control, first, a quick apply (=QA) is executed (see part a), which temporarily outputs a high K0 hydraulic pressure command value Spk0, in order to improve the initial responsiveness of the K0 hydraulic pressure PRk0. Next, a constant pressure standby for packing is executed (see part b), in which the K0 clutch 20 waits at a constant pressure to complete packing. The dashed line during constant pressure standby for packing indicates that a K0 oil pressure command value Spk0 is output to set a constant pack pressure PRk0pk, which is the K0 oil pressure PRk0 required to maintain the K0 clutch 20 in a packing-completed state. The solid line during constant pressure standby for packing indicates that a K0 oil pressure command value Spk0 is output to set the total K0 oil pressure PRk0, which is the pack pressure PRk0pk plus the K0 oil pressure PRk0 corresponding to the cranking torque Tcr. The K0 oil pressure command value Spk0 shown in dashed line and the K0 oil pressure command value Spk0 shown in solid line actually have different periods of K0 packing control, but for convenience, they are shown as the same length in FIG. 2. In this embodiment, the start type of the engine 12 that executes constant pressure standby for packing, indicated by the dashed line, is referred to as a cooperative control system start type, and the start type of the engine 12 that executes constant pressure standby for packing, indicated by the solid line, is referred to as a step (=STEP) control system start type.

[0052] After the K0 packing control ends, in order to crank the engine 12, cranking is performed by the K0 clutch 20 transmitting the cranking torque Tcr to the engine 12, i.e., K0 cranking (see time points t2-t3). The K0 oil pressure command value Spk0 during K0 cranking is the K0 oil pressure command value Spk0 for achieving the total K0 oil pressure PRk0 obtained by adding the K0 oil pressure PRk0 equivalent to the cranking torque Tcr to the pack pressure PRk0pk. This K0 oil pressure command value Spk0 adjusts the K0 oil pressure PRk0 so that the K0 clutch 20 transmits the cranking torque Tcr. During K0 cranking, an MG torque Tm equivalent to the cranking torque Tcr, i.e., an MG torque Tm for reaction force compensation, is output from the electric motor MG. During K0 cranking, when the engine rotation speed Ne is increased, engine ignition and the like are initiated, causing the engine 12 to initially explode.

[0053] After the K0 cranking is completed, a post-cranking constant pressure standby is executed (see time points t3-t4) in which the K0 torque Tk0 is reduced below the cranking torque Tcr and maintained at a predetermined torque Tk0f to wait for the K0 clutch 20 to switch to the engaged state. The predetermined torque Tk0f is a predetermined K0 torque Tk0 that is smaller than the cranking torque Tcr so as not to disturb the complete combustion of the engine 12 after the cranking is completed. Not disturbing the complete combustion of the engine 12 means not interfering with the self-sustaining rotation of the engine 12 after the initial combustion of the engine 12. From another perspective, when the engine rotation speed Ne is increased through self-sustaining rotation after ignition of the engine 12, if the K0 clutch 20 has a K0 torque Tk0 equivalent to the cranking torque Tcr, for example, the inertia of the electric motor MG and the like downstream of the K0 clutch 20 may increase the starting shock. The predetermined torque Tk0f is a predetermined K0 torque Tk0 smaller than the cranking torque Tcr to reduce start-up shock when the engine rotation speed Ne is increased by the self-sustaining rotation of the engine 12 after cranking of the engine 12 is completed. The K0 oil pressure command value Spk0 during constant pressure standby after cranking is, for example, the same as or greater than the value that maintains the K0 clutch 20 in a packing-completed state, and is a K0 oil pressure command value Spk0 for realizing a K0 torque Tk0 that does not disturb the complete combustion of the engine 12. The K0 oil pressure command value Spk0 adjusts the K0 oil pressure PRk0 so that the K0 torque Tk0 is reduced below the cranking torque Tcr and temporarily maintained at the predetermined torque Tk0f. During constant pressure standby after cranking, the engine rotation speed Ne is increased not by the K0 torque Tk0 but solely by the combustion torque of the engine 12. In this embodiment, prior to executing the constant pressure standby after cranking, a quick drain (=QD) is executed to temporarily output a low K0 oil pressure command value Spk0 in order to improve the initial responsiveness of the K0 oil pressure PRk0 (see part c).

[0054] During the constant-pressure standby after cranking, when the engine 12 reaches a stable state of self-sustaining rotation due to combustion, i.e., when the engine 12 reaches a complete combustion state, rotation synchronization control between the engine 12 and the electric motor MG is performed. In other words, synchronization control by the K0 clutch 20 to synchronize the engine rotation speed Ne and the MG rotation speed Nm, i.e., K0 synchronization control, is performed (see time t4 and thereafter). The engine rotation speed Ne is the rotation speed of the engine connecting shaft 34 and is equal to the input rotation speed of the K0 clutch 20. The MG rotation speed Nm is the rotation speed of the electric motor connecting shaft 36 and is equal to the output rotation speed of the K0 clutch 20. In other words, synchronizing the engine rotation speed Ne and the MG rotation speed Nm is equivalent to synchronizing the input rotation speed and output rotation speed of the K0 clutch 20. The complete combustion of the engine 12 is determined, for example, when a complete combustion notification is output from the engine control unit 92a. The notification of complete combustion of the engine 12 is output by the engine control unit 92a, for example, when the elapsed time from when the engine rotation speed Ne reaches a predetermined complete combustion rotation speed of the engine 12 exceeds a predetermined complete combustion notification waiting time. This complete combustion notification waiting time is predetermined, for example, taking into consideration the exhaust gas requirements of the engine 12. After the input rotation speed and output rotation speed of the K0 clutch 20 are synchronized (i.e., K0 synchronization), that is, after the K0 clutch 20 is switched to the engaged state (i.e., K0 engagement), K0 full engagement control is executed to transition the K0 clutch 20 to the fully engaged state. After the K0 clutch 20 is fully engaged by the K0 full engagement control, the start control of the engine 12 is completed (see time t5), and the fully engaged state of the K0 clutch 20 is maintained (see time t5 and thereafter).

[0055] When starting the engine 12, the clutch control unit 94 outputs a start-use K0 command value Spk0st as a K0 hydraulic pressure command value Spk0 for executing each of a series of K0 control phases from the QA phase to the K0 full engagement phase. The K0 control phases are a plurality of progression stages divided into control states of the K0 clutch 20 that are switched during the start and stop processes of the engine 12. The K0 control phases are defined as, for example, a QA phase for executing QA, a constant-pressure standby phase for packing, a K0 cranking phase for executing K0 cranking, a QD phase for executing QD, a post-cranking constant-pressure standby phase for post-cranking constant-pressure standby, a K0 synchronization phase for executing K0 synchronization control, and a K0 full engagement phase for executing K0 full engagement control. In this embodiment, a start type of the engine 12 that executes a constant-pressure standby phase after cranking to increase the engine rotation speed Ne through self-sustained rotation of the engine 12 is referred to as a TDC start type.

[0056] Note that when starting the engine 12, the clutch control unit 94 can also output a start-use K0 command value Spk0st as the K0 hydraulic pressure command value Spk0 so as not to execute constant pressure standby after cranking, but to execute K0 cranking or K0 synchronization control to raise the engine rotation speed Ne until it is synchronized with the MG rotation speed Nm. In this case, the engine control unit 92a starts ignition of the engine 12 near or after K0 synchronization. In this embodiment, a start type of the engine 12 in which the engine rotation speed Ne is raised near or to K0 synchronization by the K0 clutch 20 or the electric motor MG and then the engine 12 is ignited is referred to as a PUSH start type.

[0057] Here, the K0 torque Tk0 varies with respect to the K0 hydraulic pressure command value Spk0 due to various factors. For example, the relationship between the K0 torque Tk0 and the K0 hydraulic pressure command value Spk0 may change due to initial hardware variations or aging. Even in such cases, in order to ensure the starting performance of the engine 12, it is desirable to perform learning control that corrects the relationship between the K0 torque Tk0 and the starting K0 command value Spk0st, i.e., the starting K0 learning control CTlrnst. The relationship between the K0 torque Tk0 and the starting K0 command value Spk0st may be, for example, the correlation between the K0 torque Tk0 and the K0 hydraulic pressure command value Spk0, or the correlation between the K0 hydraulic pressure PRk0 and the K0 hydraulic pressure command value Spk0, in each of the K0 control phases executed when starting the engine 12. An example of the correlation is the correlation between the K0 torque Tk0, i.e., cranking torque Tcr, in the K0 cranking phase and the K0 oil pressure command value Spk0 during K0 cranking. The starting K0 learning control CTlrnst is a learning control that corrects, for example, variations in the K0 torque Tk0 or K0 oil pressure PRk0 relative to the K0 oil pressure command value Spk0 during each K0 control phase. In other words, the starting K0 learning control CTlrnst is a learning control that corrects, for example, variations in the K0 oil pressure command value Spk0 to obtain the desired K0 torque Tk0 or K0 oil pressure PRk0 during each K0 control phase. An example of the starting K0 learning control CTlrnst is a learning control that corrects variations in the K0 oil pressure command value Spk0 during K0 cranking to obtain the desired magnitude of the cranking torque Tcr and output period. In this embodiment, unless otherwise specified, the K0 oil pressure PRk0 and the K0 torque Tk0 represent their actual values.

[0058] When starting the engine 12, the clutch control unit 94 executes the starting K0 learning control CTlrnst based on a value that indicates the degree of a phenomenon caused by variations in the K0 torque Tk0 relative to the starting K0 command value Spk0st, that is, the learning parameter PAlrn.

[0059] An example of the learning parameter PAlrn will be given using the K0 cranking phase as an example. Because the cranking torque Tcr is output from the electric motor MG during cranking of the engine 12 by the K0 clutch 20, variations in the K0 torque Tk0 manifest as fluctuations, such as increases and decreases in the MG rotation speed Nm. For example, if the K0 torque Tk0 is smaller than the reaction-force compensation MG torque Tm, which is increased toward the cranking torque Tcr, the MG torque Tm flowing to the engine 12 side will be smaller than the reaction-force compensation MG torque Tm. Therefore, the surplus reaction-force compensation MG torque Tm that does not flow to the engine 12 side increases the MG rotation speed Nm, and variations in the K0 torque Tk0 manifest as the amount of racing in the MG rotation speed Nm. The amount of racing in the MG rotation speed Nm is a positive value within the MG rotation fluctuation amount ΔNm (=Nm - Nmb), which is the amount of fluctuation in the MG rotation speed Nm. The "Nmb" is a reference rotation speed for the MG rotation speed Nm, i.e., a reference MG rotation speed, and is, for example, the same as the AT input rotation speed Ni, or a value that takes into account the control state of the torque converter 22 relative to the AT input rotation speed Ni. On the other hand, if the K0 torque Tk0 is greater than the MG torque Tm for reaction force compensation, the MG torque Tm flowing to the engine 12 will be greater than the MG torque Tm for reaction force compensation. Therefore, a portion of the MG torque Tm for the drive torque Tr flows to the engine 12, resulting in a shortage of the MG torque Tm for the drive torque Tr, causing the MG rotation speed Nm to drop. The variation in the K0 torque Tk0 appears as a drop in the MG rotation speed Nm. The drop in the MG rotation speed Nm is a negative value of the MG rotation fluctuation amount ΔNm. Thus, an example of the learning parameter PAlrn is the MG rotation fluctuation amount ΔNm.

[0060] Incidentally, when start control of the engine 12 is executed while the vehicle is running, for example, fluctuations in the MG rotation speed Nm may occur due to changes in the control state of the LU clutch 40 or changes in the accelerator opening θacc. In this case, if the start K0 learning control CTlrnst is executed after the start control of the engine 12 is completed, the learning parameter PAlrn may include an MG rotation fluctuation amount ΔNm that is not caused by variations in the K0 torque Tk0, which may cause concerns about erroneous learning. Incorrect learning in the start K0 learning control CTlrnst may result in a deterioration of the engine's start performance.

[0061] Therefore, the electronic control unit 90 outputs an engine start request REQst to prevent a decrease in learning accuracy in the start K0 learning control CTlrnst. In other words, even in a situation where starting control of the engine 12 is not necessary due to requirements such as the required drive torque Trdem, charging of the battery 54, and warming up of the engine 12, the electronic control unit 90 outputs the engine start request REQst in order to perform highly accurate learning in the start K0 learning control CTlrnst. An engine start request REQst for performing the start K0 learning control CTlrnst, i.e., an engine start request REQst that requires execution of the start K0 learning control CTlrnst, is an engine start request REQst based on learning requirements. In this embodiment, an engine start request REQst determined based on requirements such as the required drive torque Trdem, charging of the battery 54, and warming up of the engine 12 is referred to as an engine start request REQst based on other requirements to distinguish it from an engine start request REQst based on learning requirements.

[0062] When predetermined learning permission conditions CDlrnf, which are predetermined learning permission conditions, are met, the clutch control unit 94 outputs an engine start request REQst based on the learning requirements and executes the start K0 learning control CTlrnst when starting the engine 12 in accordance with the engine start request REQst based on the learning requirements. The engine control unit 92a determines whether there is an engine start request REQst based on whether the clutch control unit 94 has output an engine start request REQst based on the learning requirements, separately from the engine start request REQst based on other requirements determined by the engine control unit 92a itself. The predetermined learning permission conditions CDlrnf are, for example, predetermined conditions for determining whether the learning accuracy of the start K0 learning control CTlrnst is ensured and whether problems are unlikely to occur even if the engine 12 is started due to the start K0 learning control CTlrnst.

[0063] The predetermined learning permission condition CDlrnf includes, for example, a predetermined condition for determining whether the learning parameter PAlrn is unlikely to include values ​​other than those resulting from variations in the K0 torque Tk0, i.e., a predetermined learnable condition CDposf, which is a predetermined learnable condition. A situation in which the learning parameter PAlrn is unlikely to fluctuate due to factors other than those resulting from variations in the K0 torque Tk0 is, for example, a state in which the vehicle 10 is stopped, in which the MG rotation speed Nm is unlikely to fluctuate. The predetermined learnable condition CDposf includes the condition that the vehicle 10 is stopped.

[0064] Starting the engine 12 immediately after the vehicle 10 transitions from BEV driving to a stopped state may cause the driver discomfort, which is undesirable from the perspective of drivability. Furthermore, the driver's operation is reflected, for example, in the shift position POSsh of the shift lever 64. Therefore, the predetermined learning permission condition CDlrnf includes a condition that the predetermined learning enablement condition CDposf is met consecutively for the start request delay time TMdel. The clutch control unit 94 sets the start request delay time TMdel based on each of the multiple shift positions POSsh of the shift lever 64. The start request delay time TMdel is a predetermined time period designed to suppress discomfort caused by starting the engine 12 while the vehicle is stopped, for example.

[0065] Considering factors such as shock suppression, it is preferable that the TDC start type start control of the engine 12 be performed with the automatic transmission 24 in a non-driving position such as P or N, which is in a neutral state. Therefore, when the vehicle 10 comes to a stop, it is preferable to make the start request delay time TMdel longer when the shift operation position POSsh is in a driving operation position such as R or D, compared to when it is in a non-driving operation position such as P or N. When the shift operation position POSsh is in a driving operation position, the clutch control unit 94 sets the start request delay time TMdel to a longer value than when it is in a non-driving operation position.

[0066] The predetermined learnable condition CDposf may include, for example, a condition that the accelerator is off and no acceleration operation is being performed by the driver. The predetermined learnable condition CDposf may also include, for example, a condition that a hydraulic system such as the K0 solenoid SLk0 provided in the hydraulic control circuit 56 is not failing. The predetermined learnable condition CDposf may also include, for example, a condition that the hydraulic oil temperature THoil is equal to or higher than a predetermined oil temperature at which a decrease in the responsiveness of the K0 hydraulic pressure PRk0 is suppressed. The predetermined learnable condition CDposf may also include, for example, a condition that the shift operation position POSsh is the P operation position, or that the shift operation position POSsh is the D, N, or R operation position and the brake is on and the wheel brake is activated by the driver.

[0067] When the vehicle 10 is stopped in the BEV drive mode with the accelerator pedal released, the motor control unit 92b executes, for example, MG idling control CTmid, which is idling control of the motor MG. The MG idling control CTmid is a control for idling the motor MG by maintaining the MG rotation speed Nm at, for example, a predetermined MG idle rotation speed Nmidl, which is a predetermined idling rotation speed of the motor MG. The MG idling control CTmid is also a control for outputting a creep torque Tcp from the motor MG when the vehicle 10 is stopped, for example, under the condition where the engine 12 is stopped and the accelerator pedal is released. The creep torque Tcp is a predetermined torque for causing the vehicle 10 to creep slowly with the accelerator pedal released, for example, when the brake is released during a temporary stop. This torque is used to cause the vehicle 10 to creep when the brake is released and the accelerator pedal is released while the vehicle 10 is stopped. Furthermore, when the engine 12 is stopped and the vehicle 10 is in a predetermined state where the creep torque Tcp is unnecessary under the condition where the creep torque Tcp is output from the electric motor MG, the electric motor control unit 92b executes creep cut control CTccp as torque cut control that does not output the creep torque Tcp from the electric motor MG. The predetermined state is, for example, a predetermined state of the vehicle 10, such as a non-driving position where the automatic transmission 24 is in a neutral state or a vehicle stopped with the brakes on.

[0068] In order to ensure the learning accuracy of the startup K0 learning control CTlrnst, it is preferable that the startup K0 learning control CTlrnst be executed when starting the engine 12 in a stable state where the MG rotation speed Nm is equal to or higher than a certain level so as to ensure the discharge flow rate of the hydraulic oil OIL from the MOP 58. For this reason, the predetermined learning enablement condition CDposf may include, for example, a condition that the creep cut control CTccp is released.

[0069] Starting the engine 12 in response to the engine start request REQst based on the learning requirements is not necessary in terms of the required drive torque Trdem, charging the battery 54, warming up the engine 12, etc., so it is not preferable to always perform this while the vehicle is stopped, considering fuel economy and exhaust gas emissions. Therefore, the predetermined learning permission condition CDlrnf may include, for example, a condition that the engine 12 has been started a predetermined number of times REPf or more in succession when the start K0 learning control CTlrnst is not being performed. The predetermined number of times REPf is a threshold value that is predetermined in consideration of, for example, fuel economy and exhaust gas emissions.

[0070] The start types of the engine 12 are classified into a cooperative control system start type and a step control system start type, and further into a TDC start type and a push start type. Therefore, the start types of the engine 12 are broadly classified into a cooperative control system TDC start type, a cooperative control system push start type, a step control system TDC start type, and a step control system push start type. In addition, because the TDC start type increases the engine rotation speed Ne through self-sustained rotation of the engine 12, the cranking torque Tcr for the TDC start type is predetermined to be smaller than that for the push start type, for example, 90 [Nm]. In other words, the TDC start type is not executed unless the required cranking torque Tcr is 90 [Nm] or less. The required cranking torque Tcr is calculated by the engine control unit 92a as a predetermined value based on the crank angle Acr when the engine 12 is stopped. On the other hand, when the required cranking torque Tcr exceeds 90 [Nm], the push start type is executed. In the push start type, the cranking torque Tcr can be set to, for example, 120 [Nm] or 140 [Nm]. 140 [Nm] is, for example, the maximum value of the cranking torque Tcr. In the push start type, the cranking torque Tcr is set to 120 [Nm] when the required cranking torque Tcr is 120 [Nm] or less, except when the cranking torque Tcr at the engine start request REQst based on the learning requirements is 140 [Nm]. Therefore, in this embodiment, the start types of the engine 12 are exemplified as a cooperative control 90 Nm TDC start type, a cooperative control 120 Nm PUSH start type, a cooperative control 140 Nm PUSH start type, a step control 90 Nm TDC start type, a step control 120 Nm PUSH start type, and a step control 140 Nm PUSH start type.

[0071] The clutch control unit 94 executes the start K0 learning control CTlrnst for each start type of the engine 12. A predetermined priority is set for each start type of the engine 12, and the clutch control unit 94 basically executes the unconverged start K0 learning control CTlrnst in accordance with the predetermined priority. During the start K0 learning control CTlrnst, the clutch control unit 94 determines that the start K0 learning control CTlrnst for the executed start type of the engine 12 has converged when, for example, the correction amount when correcting the variation in the K0 hydraulic pressure command value Spk0 is suppressed to less than a predetermined value, or when, for example, the value of the learning parameter PAlrn is suppressed to less than a predetermined value.

[0072] The clutch control unit 94 determines that the correction by the start K0 learning control CTlrnst is progressing more as the start K0 learning control CTlrnst converges more frequently or the number of times the start K0 learning control CTlrnst converges is greater for each start type of the engine 12. If the correction by the start K0 learning control CTlrnst is progressing, the frequency of outputting the engine start request REQst based on the learning requirements may be reduced. The clutch control unit 94 sets the predetermined number of start times REPf to a larger value as the correction by the start K0 learning control CTlrnst is progressing more. For example, when the start K0 learning control CTlrnst has not converged for any start type of the engine 12, the clutch control unit 94 sets the predetermined number of start times REPf to the smallest value. Specifically, when the start K0 learning control CTlrnst has not been executed for any start type of the engine 12, the clutch control unit 94 may set the predetermined number of start times REPf to zero, for example.

[0073] When starting the engine 12 in response to the engine start request REQst based on the learning requirements, the start K0 learning control CTlrnst can be executed once the start of the engine 12 is complete, so the engine 12 can be stopped promptly after the start of the engine 12 is complete. However, if the engine 12 is stopped immediately after the start of the engine 12 in response to the engine start request REQst based on the learning requirements is completed, the driver may feel busy while the engine 12 is being started. The clutch control unit 94 causes the engine control unit 92a to maintain the operating state of the engine 12 until a predetermined operating time TMonf or more has elapsed from the time the start of the engine 12 in response to the engine start request REQst based on the learning requirements is completed.

[0074] Fig. 3 is a flowchart illustrating the main control operations of the electronic control unit 90, specifically, the control operations for suppressing a decline in the starting performance of the engine 12, which are executed repeatedly, for example. Fig. 4 is a flowchart illustrating the control operations for advancing correction by the starting K0 learning control CTlrnst in the cooperative control system start type, which is a subroutine corresponding to step S60a in the flowchart of Fig. 3. Fig. 5 is a flowchart illustrating the control operations for advancing correction by the starting K0 learning control CTlrnst in the step control system start type, which is a subroutine corresponding to step S70a in the flowchart of Fig. 3. Fig. 6 is a flowchart illustrating the control operations for further advancing correction by the starting K0 learning control CTlrnst, which is a subroutine corresponding to step S80a in the flowchart of Fig. 3.

[0075] 3, each step in the flowchart corresponds to a function of the clutch control unit 94 (CLT_ECU). In step (hereinafter, "step" will be omitted) S10a, it is determined whether the drive mode is the BEV drive mode. If the determination in S10a is affirmative, it is determined in S20a whether a part of the predetermined learnable conditions CDposf has been met continuously for the start request delay time TMdel. Here, the part of the predetermined learnable conditions CDposf is, for example, a condition that the vehicle 10 is in a stopped state. The part of the predetermined learnable conditions CDposf may also include a condition that the accelerator is in an off state, a condition that the hydraulic system is not failing, a condition that the hydraulic oil temperature THoil is equal to or higher than a predetermined oil temperature, a condition that the shift operation position POSsh is in the P operation position, or a condition that the shift operation position POSsh is in the D, N, R operation position and the brake is on, etc. On the other hand, if the engine 12 is started while the creep cut control CTccp is being executed, the creep cut control CTccp is released, so the predetermined learning enablement condition CDposf here does not necessarily have to include, for example, a condition that the creep cut control CTccp is released. Since the creep torque Tcp, MG idle rotation speed Nmidl, etc. cannot be restored to stable values ​​immediately after the creep cut control CTccp is released, the start of output of the K0 hydraulic pressure command value Spk0 is delayed after the release of the creep cut control CTccp begins until the creep torque Tcp, MG idle rotation speed Nmidl, etc. are stabilized. In other words, the output of the QA K0 hydraulic pressure command value Spk0 is put on hold. If the determination in S20a above is affirmative, then in S30a, it is determined whether the engine 12 has been started a predetermined number of times in succession, REPf or more, without the start K0 learning control CTlrnst being executed. If the determination in S30a is positive, in S40a, it is determined whether or not all of the startup K0 learning controls CTlrnst for the cooperative control system startup type have converged, that is, whether or not at least one of the multiple startup K0 learning controls CTlrnst for the cooperative control system startup type has not yet converged.If the determination in S40a is negative, then in S50a it is determined whether or not all of the start K0 learning controls CTlrnst for the STEP control system start type have converged, that is, whether or not at least one of the multiple start K0 learning controls CTlrnst for the STEP control system start type has not yet converged. If the determination in S40a is positive, then in S60a, determination unit 1 is executed. If the determination in S50a is positive, then in S70a, determination unit 2 is executed. If the determination in S50a is negative, then in S80a, determination unit 3 is executed.

[0076] 4, the determination unit 1 in S60a is executed. Specifically, in S60a01, it is determined whether the cranking torque Tcr in the cooperative control system start type is in the 120 [Nm] range, i.e., whether the start K0 learning control CTlrnst in the cooperative control 120 Nm PUSH start type has not yet converged. If the determination in S60a01 is negative, it is determined in S60a02 whether the cranking torque Tcr in the cooperative control system start type is in the 90 [Nm] range, i.e., whether the start K0 learning control CTlrnst in the cooperative control 90 Nm TDC start type has not yet converged. If the determination in S60a02 is positive, it is determined in S60a03 whether the shift position POSsh is in a non-travel position such as the P or N position. If the determination in S60a02 is negative, or if the determination in S60a03 is negative, then in S60a04, a determination is made as to whether the cranking torque Tcr for the cooperative control system start type is in the 140 Nm region, i.e., whether the start K0 learning control CTlrnst for the 140 Nm PUSH cooperative control start type has not yet converged. If the determination in S60a04 is negative, then in S60a05, a determination is made as to whether the start K0 learning control CTlrnst for the 90 Nm TDC cooperative control start type has the fewest number of convergences among the cooperative control system start types. If the determination in S60a05 is positive, then in S60a06, a determination is made as to whether the shift position POSsh is a non-travel position such as P or N. If the determination in S60a01 is positive, then in S60a07, an engine start request REQst is output to start the engine 12 using the 120 Nm PUSH cooperative control start type. If the determination in S60a03 above is affirmative, an engine start request REQst to start the engine 12 using the cooperative control 90 Nm TDC start type is output in S60a08. If the determination in S60a04 above is affirmative, an engine start request REQst to start the engine 12 using the cooperative control 140 Nm PUSH start type is output in S60a09. If the determination in S60a06 above is affirmative, an engine start request REQst to start the engine 12 using the cooperative control 90 Nm TDC start type is output in S60a10.If the judgment in S60a05 above is negative, or if the judgment in S60a06 above is negative, in S60a11, an engine start request REQst is output to start the engine 12 using the cooperative control 120NmPUSH start type or the cooperative control 140NmPUSH start type, whichever has the fewer number of convergences.

[0077] 5, determination section 2 of S70a is executed. Specifically, in S70a01, it is determined whether the cranking torque Tcr in the step control system start type is in the 120 [Nm] range, i.e., whether the start K0 learning control CTlrnst in the step control 120 Nm PUSH start type has not yet converged. If the determination in S70a01 is negative, it is determined in S70a02 whether the cranking torque Tcr in the step control system start type is in the 90 [Nm] range, i.e., whether the start K0 learning control CTlrnst in the step control 90 Nm TDC start type has not yet converged. If the determination in S70a02 is positive, it is determined in S70a03 whether the shift position POSsh is in a non-travel position such as the P or N position. If the determination in S70a02 is negative, or if the determination in S70a03 is negative, then in S70a04, a determination is made as to whether the cranking torque Tcr in the step control system start type is in the 140 Nm region, i.e., whether the start K0 learning control CTlrnst in the step control 140 Nm PUSH start type has not yet converged. If the determination in S70a04 is negative, then in S70a05, a determination is made as to whether the start K0 learning control CTlrnst in the step control 90 Nm TDC start type has the fewest number of convergences among the step control system start types. If the determination in S70a05 is positive, then in S70a06, a determination is made as to whether the shift position POSsh is a non-travel position such as P or N. If the determination in S70a01 is positive, then in S70a07, an engine start request REQst is output to start the engine 12 in the step control 120 Nm PUSH start type. If the determination in S70a03 is affirmative, an engine start request REQst is output in S70a08 to start the engine 12 using step control with a 90 Nm TDC start type. If the determination in S70a04 is affirmative, an engine start request REQst is output in S70a09 to start the engine 12 using step control with a 140 Nm PUSH start type.If the determination in S70a06 is affirmative, an engine start request REQst is output in S70a10 to start the engine 12 using the STEP control 90Nm TDC start type. If the determination in S70a05 is negative, or if the determination in S70a06 is negative, an engine start request REQst is output in S70a11 to start the engine 12 using either the STEP control 120Nm PUSH start type or the STEP control 140Nm PUSH start type, whichever has the fewer number of convergences.

[0078] In FIG. 6, the determination unit 3 in S80a is executed. Specifically, in S80a01, it is determined whether the start K0 learning control CTlrnst in the cooperative control 90 Nm TDC start type has converged the fewest number of times. If the determination in S80a01 is positive, it is determined in S80a02 whether the shift operation position POSsh is a non-driving operation position such as P or N operation position. If the determination in S80a01 is negative, or if the determination in S80a02 is negative, it is determined in S80a03 whether the start K0 learning control CTlrnst in the step control 90 Nm TDC start type has converged the fewest number of times. If the determination in S80a03 is positive, it is determined in S80a04 whether the shift operation position POSsh is a non-driving operation position such as P or N operation position. If the determination in S80a02 is affirmative, an engine start request REQst to start the engine 12 using the cooperative control 90 Nm TDC start type is output in S80a05. If the determination in S80a04 is affirmative, an engine start request REQst to start the engine 12 using the step control 90 Nm TDC start type is output in S80a06. If the determination in S80a03 is negative or if the determination in S80a04 is negative, an engine start request REQst to start the engine 12 using the start type with the fewest convergence counts is output in S80a07.

[0079] Returning to FIG. 3 , following S60a, S70a, or S80a, in S90a, after outputting the engine start request REQst based on the learning requirements, the start of the engine 12 is completed, and it is determined whether or not a predetermined operating time TMonf has elapsed since the completion of the start. If the determination in S90a is negative, in S100a, the engine start request REQst for starting the engine 12 using the start type determined in S60a, S70a, or S80a is continuously output. Following S100a, S90a is executed. If the determination in S10a is negative, or if the determination in S20a is negative, or if the determination in S30a is negative, or if the determination in S90a is positive, in S110a, the engine start request REQst based on the learning requirements is not output.

[0080] FIG. 7 is a flowchart illustrating the main control operations of the electronic control device 90, which are for suppressing a decrease in the starting performance of the engine 12, and is executed repeatedly together with the flowchart of FIG. 3, for example.

[0081] In FIG. 7, each step of the flowchart corresponds to a function of the engine control unit 92a (ENG_ECU). In S10b, it is determined whether an engine start request REQst based on the learning requirements is present. If the determination in S10b is affirmative, it is determined in S20b whether an engine start request REQst for starting the engine 12 in a TDC start type has been output. If the determination in S20b is affirmative, it is determined in S30b whether the shift position POSsh is a non-traveling position such as the P or N position. If the determination in S30b is affirmative, it is determined in S40b whether the engine 12 can be started in a TDC start type based on, for example, the crank angle Acr, which is used to calculate the required cranking torque Tcr. If the determination in S40b is affirmative, it is determined in S50b whether the cranking torque Tcr is 90 [Nm] or less when starting the engine 12 in a TDC start type based on, for example, the crank angle Acr. If the determination in S50b is affirmative, the process proceeds to S60b, where the start type of the engine 12 is determined to be the TDC start type and the cranking torque Tcr is set to 90 [Nm]. If the determination in S20b is negative, or if the determination in S30b is negative, or if the determination in S40b is negative, or if the determination in S50b is negative, the process proceeds to S70b, where the start type of the engine 12 is determined to be the PUSH start type. Next, in S80b, it is determined whether the cranking torque Tcr is 120 [Nm] or less when starting the engine 12 in the PUSH start type, based on, for example, the crank angle Acr. If the determination in S80b is affirmative, the process proceeds to S90b, where the cranking torque Tcr is set to 120 [Nm]. If the determination in S80b is negative, the process proceeds to S100b, where the cranking torque Tcr is set to 140 [Nm]. Following S60b, S90b, or S100b, in S110b, it is determined whether an engine start request REQst for starting the engine 12 in the cooperative control system start type has been output.If the determination in S110b is positive, then in S120b, it is determined whether there is a risk of hesitation, i.e., a delayed response, when starting the engine 12 in the cooperative control system start type, based on, for example, the accelerator opening θacc and the output limit of the battery 54. If the determination in S110b is negative, or if the determination in S120b is positive, then in S130b, a start command in the step control system start type is output. If the determination in S120b is negative, then in S140b, a start command in the cooperative control system start type is output. If the determination in S10b is negative, then in S150b, control is performed in accordance with the engine start request REQst based on other requirements.

[0082] As described above, according to this embodiment, when the predetermined learning permission condition CDlrnf is met, the clutch control unit 94, which executes the start K0 learning control CTlrnst based on the learning parameter PAlrn, outputs the engine start request REQst based on the learning requirements, and executes the start K0 learning control CTlrnst when starting the engine 12 in response to the engine start request REQst based on the learning requirements. This ensures that the engine 12 is started in a state suitable for the start K0 learning control CTlrnst, making it difficult for changes other than those due to variations in the K0 torque Tk0 to be included in the learning parameter PAlrn, thereby suppressing a decrease in learning accuracy. This therefore suppresses a decrease in the starting performance of the engine 12.

[0083] Furthermore, according to this embodiment, the predetermined learning permission condition CDlrnf includes the condition that the predetermined learning enablement condition CDposf, which includes the condition that the vehicle 10 is in a stopped state, is met consecutively for the start request delay time TMdel, and the clutch control unit 94 sets the start request delay time TMdel based on each of the multiple shift operation positions POSsh of the shift lever 64. Therefore, the engine 12 is started in a state suitable for the start K0 learning control CTlrnst, and it is possible to suppress any discomfort that may occur when the engine 12 is started while the vehicle 10 is stopped.

[0084] Furthermore, according to this embodiment, the clutch control unit 94 sets the start request delay time TMdel to a longer value when the shift operation position POSsh is a drive operation position compared to when it is a non-drive operation position, so that starting of the engine 12 immediately after stopping is suppressed, or it is possible to expect a switching operation from a drive operation position to a non-drive operation position before the output of the engine start request REQst is determined.

[0085] Furthermore, according to this embodiment, the predetermined learning permission condition CDlrnf includes a condition that the engine 12 has been started consecutively a predetermined number of times REPf or more without the start K0 learning control CTlrnst being executed. Therefore, starting of the engine 12 in response to the engine start request REQst based on the learning requirements is suppressed, thereby suppressing deterioration in fuel economy and taking into consideration exhaust gas requirements.

[0086] Furthermore, according to this embodiment, the clutch control unit 94 sets the predetermined number of start-ups REPf to a larger value as the correction by the start-up K0 learning control CTlrnst progresses, thereby further suppressing deterioration in fuel economy and taking exhaust gas requirements into consideration.

[0087] Furthermore, according to this embodiment, the clutch control unit 94 causes the engine control unit 92a to maintain the operating state of the engine 12 until a predetermined operating time TMonf or more has elapsed from the time when the start of the engine 12 in response to the engine start request REQst based on the learning requirements is completed, thereby suppressing the feeling of being busy caused by the engine 12 being stopped immediately when the start of the engine 12 in response to the engine start request REQst based on the learning requirements is completed.

[0088] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0089] For example, in the above-described embodiment, the starting command value is the K0 hydraulic pressure command value Spk0, but the invention is not limited to this. The starting command value may be, for example, a starting K0 command current value Sik0, a starting K0 command voltage value, or a drive current or drive voltage value for driving the K0 solenoid SLk0.

[0090] In the above-described embodiment, the start K0 learning control CTlrnst is executed when the engine 12 is started in response to an engine start request REQst based on a learning requirement in order to perform highly accurate learning, but this does not preclude the execution of the start K0 learning control CTlrnst when the engine 12 is started in response to an engine start request REQst based on another requirement. For example, when the engine 12 is started in response to a charge request, a warm-up request, or the like, and there is little risk of erroneous learning, the start K0 learning control CTlrnst may be executed when the engine 12 is started in response to an engine start request REQst based on another requirement.

[0091] Furthermore, in the above-described embodiment, the start request delay time TMdel is set based on the shift operation position POSsh. However, for example, the start request delay time TMdel may be set based on the degree of progress of correction by the start K0 learning control CTlrnst in addition to the shift operation position POSsh.

[0092] In the above-described embodiment, the start types of the engine 12 are categorized into a cooperative control system start type and a step control system start type, and also into a TDC start type and a push start type. However, this is not limiting. For example, the start types may be categorized into an ignition start type, in which the engine 12 is started by igniting simultaneously with or before cranking, a TDC start type, and a push start type. Furthermore, the distinction between the cooperative control system start type and the step control system start type does not necessarily have to be made.

[0093] In addition, in the above-described embodiment, the cranking torque Tcr is divided into 90 [Nm], 120 [Nm], and 140 [Nm] as examples, but the cranking torque Tcr may be divided into values ​​that are set according to suitability, for example, depending on the vehicle type, etc.

[0094] Furthermore, in the above-described embodiment, the required cranking torque Tcr is calculated based on the crank angle Acr, but it may also be calculated based on the temperature of the cooling water for the engine 12 in addition to the crank angle Acr.

[0095] In addition, in the above-described embodiment, a planetary gear automatic transmission is used as the automatic transmission 24, but the present invention is not limited to this. The automatic transmission 24 may be a synchronous mesh parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission). In short, the present invention can be applied to any vehicle equipped with a clutch provided between the engine and the electric motor.

[0096] In the above-described embodiment, the torque converter 22 is used as the fluid transmission device, but the present invention is not limited to this. For example, instead of the torque converter 22, another fluid transmission device, such as a fluid coupling that does not have a torque amplifying effect, may be used as the fluid transmission device. Alternatively, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

[0097] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0098] 10: Vehicle 12: Engine 14: Drive wheel 16: Power transmission device 20:K0 clutch (clutch) 56: Hydraulic control circuit 64: Shift lever (shift operation member) 90: Electronic control device (control device) 92a: Engine control unit 92b: Motor control unit 94: Clutch control unit MG: Electric motor SP: Power source

Claims

1. A control device for a vehicle including 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, a clutch provided between the engine and the electric motor in the power transmission path, and a hydraulic control circuit that supplies adjusted hydraulic pressure used to switch a control state of the clutch, an engine control unit that determines whether or not an engine start request is present, and when it is determined that the engine start request is present, controls the engine so that the engine starts operating; a clutch control unit that outputs a start command value for adjusting the hydraulic pressure by the hydraulic control circuit so as to switch the control state of the clutch from a released state to an engaged state when starting the engine, and that executes learning control to correct a relationship that represents a correlation between the torque capacity of the clutch and the start command value based on a numerical value that represents the degree of a phenomenon caused by a variation in the torque capacity of the clutch relative to the start command value; an electric motor control unit that controls the electric motor so that the electric motor outputs a cranking torque required for cranking to increase the rotational speed of the engine, the cranking torque being transmitted via the clutch when the engine is started; It contains the clutch control unit outputs an engine start request based on a learning requirement, which is the engine start request that requires execution of the learning control, when a predetermined learning permission condition is established, and executes the learning control when starting the engine in response to the engine start request based on the learning requirement, the predetermined learning permission condition includes a condition that predetermined learning enablement conditions, including a condition that the vehicle is in a stopped state, are met continuously for a start request delay time, the clutch control unit sets the start request delay time based on each of a plurality of operating positions of a shift operating member operated by a driver, the plurality of operating positions corresponding to a plurality of shift positions of a power transmission device that transmits power from a power source including the engine and the electric motor to the drive wheels.

2. 2. The vehicle control device according to claim 1, wherein the clutch control unit sets the start request delay time to a longer value when the operation position is a drive operation position that selects a drive position in which power transmission in the power transmission device is enabled, compared to when the operation position is a non-drive operation position that selects a non-drive position in which power transmission in the power transmission device is interrupted.

3. 3. The vehicle control device according to claim 1, wherein the predetermined learning permission condition includes a condition that the engine has been started a predetermined number of times in succession without the learning control being executed.

4. 4. The vehicle control device according to claim 3, wherein the clutch control unit sets the predetermined number of starts to a larger value as the correction by the learning control progresses.

5. A vehicle control device as described in any one of claims 1 to 4, characterized in that the clutch control unit maintains the operating state of the engine using the engine control unit until a predetermined operating time has elapsed from the time when the engine start-up in response to the engine start request based on the learning requirements is completed.

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