Vehicle control device

Abstract

To provide a control device of a vehicle which can determine occurrence of an ON failure in a connection / disconnection clutch for connecting / disconnecting power transmission between an engine and an electric motor when a vehicle stop state is set from a travel state in which the engine is used as a power source.SOLUTION: An electronic control device 80 executes: (a) electric motor stop control in which an operation state of an engine 12 is maintained, a connection / disconnection clutch K0 is made a release state and an electric motor MG is stopped when a vehicle stop state is set from a travel state in which the engine 12 is used as a power source; and (b) engine stop control for stopping the engine 12 when differential rotation ΔNk0 of the connection / disconnection clutch K0 becomes a determination value ΔNk0_jdg or more until a prescribed period T is elapsed from starting of the execution of the electric motor stop control. The electronic control device determines (c) an ON failure that the connection / disconnection switch K0 is in a normally engaged state when the differential rotation ΔNk0 is less than the determination value ΔNk0_jdg until the prescribed period T is elapsed from starting of the execution of the electric motor stop control.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle that includes an engine and an electric motor as power sources, and a disconnecting clutch that connects and disconnects power transmission between the engine and the electric motor. [Background technology]

[0002] There is known a vehicle that includes an engine and an electric motor as power sources, a disconnecting clutch that connects and disconnects the power transmission between the engine and the electric motor, and a starting clutch that connects and disconnects the power transmission between the electric motor and a pair of drive wheels. For example, there is one described in Patent Document 1. In the vehicle described in Patent Document 1, when the vehicle starts, it is determined whether a differential rotation of the starting clutch is less than a predetermined determination value, thereby determining that an on-failure has occurred in which the starting clutch is constantly engaged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 156931 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to determine whether an on-failure has occurred in which the disconnecting clutch is always engaged, it is necessary to determine whether the differential rotation of the disconnecting clutch is less than a predetermined determination value. During BEV driving using only the electric motor as a power source, the disconnecting clutch is in a released state, so a differential rotation can occur in the disconnecting clutch. However, during HEV driving using the engine as a power source, the disconnecting clutch is in an engaged state, so it is not possible to determine whether an on-failure has occurred in the disconnecting clutch. Furthermore, when the vehicle transitions from HEV driving to a stopped state, the engine and electric motor are stopped simultaneously to improve the fuel efficiency of the engine and the power efficiency of the electric motor, so it is also not possible to determine whether an on-failure has occurred in the disconnecting clutch in this case.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can determine if an on-failure has occurred in the disconnecting clutch that disconnects the power transmission between the engine and the electric motor when the vehicle goes from a running state using the engine as a power source to a stopped state. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle that has an engine and an electric motor as power sources, and an on-off clutch that disconnects power transmission between the engine and the electric motor, which (a) when the vehicle changes from a running state using the engine as a power source to a stopped state, maintains the operating state of the engine, executes release control to release the on-off clutch, and executes electric motor stop control to stop the electric motor, (b) if the differential rotation of the on-off clutch becomes equal to or greater than a predetermined judgment value between the start of execution of the electric motor stop control and the lapse of a predetermined period of time, executes engine stop control to stop the engine, and (c) if the differential rotation is less than the judgment value between the start of execution of the electric motor stop control and the lapse of the predetermined period of time, determines that an on-failure has occurred in which the on-off clutch is always engaged. [Effects of the Invention]

[0007] According to the vehicle control device of the present invention, (a) when the vehicle transitions from a running state using the engine as a power source to a stopped state, the engine is maintained in an operating state, release control is executed to release the disconnecting clutch, and electric motor stop control is executed to stop the electric motor, (b) if the differential rotation of the disconnecting clutch becomes equal to or greater than a predetermined judgment value during the period from the start of execution of the electric motor stop control until the predetermined period has elapsed, engine stop control is executed to stop the engine, and (c) if the differential rotation is less than the judgment value during the period from the start of execution of the electric motor stop control until the predetermined period has elapsed, it is determined that an on-failure has occurred in the disconnecting clutch, in which the disconnecting clutch is always engaged. When the vehicle transitions from a running state using the engine as a power source to a stopped state, the electric motor is stopped while the engine is maintained in an operating state, so that an on-failure of the disconnecting clutch can be detected. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and also shows an example of a functional block diagram illustrating the control functions of the electronic control device. [Figure 2] A schematic diagram explaining the rotational speeds of the engine, electric motor, and drive wheels in each state of the vehicle, where (a) shows the HEV driving state, (b) shows the state in which the engine is maintained in operation while the vehicle is stopped, (c) shows the state after the electric motor stop control is executed when the disconnecting clutch is normal, (d) shows the state in which the engine is stopped due to the execution of engine stop control when the disconnecting clutch is normal, (e) shows the state at the start of driving in BEV driving mode when the disconnecting clutch is normal, (f) shows the state after the electric motor stop control is executed when the disconnecting clutch has an on-failure, and (g) shows the state at the start of driving in HEV driving mode when the disconnecting clutch has an on-failure. [Figure 3] 2 is an example of a flowchart illustrating a main part of the control operation of the electronic control device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control unit 80 according to an embodiment of the present invention, and also shows an example of a functional block diagram illustrating the control functions of the electronic control unit 80.

[0011] The vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which function as power sources. The vehicle 10 is equipped with a disconnecting clutch K0 that connects and disconnects power transmission between the engine 12 and the electric motor MG. In the vehicle 10, a power transmission path PT between the power source and a pair of drive wheels 14 is connected, in order from the power source side, to a rotor shaft 22, a starting clutch WSC, a transmission shaft 24, a differential 18, and a pair of drive shafts 26, all of which are well-known components. The vehicle 10 also includes an inverter 30, a hydraulic control circuit 50, and an electronic control device 80.

[0012] The engine 12 is a well-known internal combustion engine such as a gasoline engine or a diesel engine. The engine torque Te [Nm], which is the output torque of the engine 12, is controlled by controlling an engine control device that includes a throttle actuator, a fuel injection device, an ignition device, etc.

[0013] The electric motor MG is, for example, a rotating electric machine having a motor function and a generator function, and is a so-called motor generator. The electric motor MG outputs MG torque Tmg [Nm], which is the output torque of the electric motor MG, as power by controlling the inverter 30 using power supplied from a battery (not shown). The electric motor MG also generates power using the power of the engine 12 and the driven force input from the pair of drive wheels 14, and charges the generated power into the battery. When no particular distinction is made, the above-mentioned power is also referred to as driving force, torque, and force.

[0014] The connecting / disconnecting clutch K0 is a clutch that connects and disconnects the power transmission between the engine 12 and the electric motor MG. One end of the connecting / disconnecting clutch K0 is connected to the engine 12 via the crankshaft 20, and the other end is connected to the rotor shaft 22 of the electric motor MG. The starting clutch WSC is a clutch that mechanically connects and disconnects the power transmission path PT. One end of the starting clutch WSC is connected to the rotor shaft 22, and the other end is connected to the differential 18 via the transmission shaft 24.

[0015] The on-off clutch K0 and the starting clutch WSC are hydraulic friction engagement devices, each composed of a multi-plate or single-plate clutch pressed by an actuator. The on-off clutch K0 and the starting clutch WSC have their torque capacities changed by the regulated hydraulic pressure supplied from the hydraulic control circuit 50, thereby switching between various operating states, such as a fully engaged state (connected state), a slipping engaged state (half-engaged state), and a released state (disconnected state). Unless otherwise specified, the "engaged state" described below refers to the "fully engaged state." Torque capacity is the magnitude of torque that a clutch can transmit, and is equivalent to the clutch engagement force.

[0016] A brake device 40 is provided on each of the pair of drive shafts 26 and a pair of axles for driven wheels (not shown). The brake device 40 is, for example, a so-called disc brake in which brake pads clamp a disk that rotates integrally with the pair of drive shafts 26, generating braking force through friction. The brake device 40 applies braking torque to the pair of drive wheels 14 and driven wheels in response to, for example, the driver's depression of a brake pedal 62. The brake device 40 controls the clamping force of the brake pads by, for example, changing the regulated hydraulic pressure supplied from a hydraulic control circuit 50.

[0017] The hydraulic control circuit 50 uses the hydraulic oil discharged by an oil pump (not shown) provided in the vehicle 10 as the source pressure and supplies adjusted hydraulic pressure to the actuators that control the operating states of the on-off clutch K0 and the starting clutch WSC. The hydraulic control circuit 50 uses the hydraulic oil discharged by the oil pump as the source pressure and supplies adjusted hydraulic pressure to the actuators that control the clamping force of the brake pads in the brake device 40.

[0018] The vehicle 10 can be selectively switched between a BEV (Battery Electric Vehicle) driving mode, which realizes BEV driving using only the electric motor MG as a power source, and an HEV (Hybrid Electric Vehicle) driving mode, which realizes HEV driving using at least the engine 12 as a power source. During BEV driving, the on-off clutch K0 is released and the starting clutch WSC is engaged. During HEV driving, both the on-off clutch K0 and the starting clutch WSC are engaged.

[0019] In the vehicle 10, cranking torque output from the electric motor MG during BEV running is transmitted to the engine 12 via the engaged disconnecting clutch K0, which starts the engine 12 and switches the engine 12 from a stopped state to an operating state, thereby switching to HEV running. Furthermore, during HEV running, the disconnecting clutch K0 is released and the engine 12 is stopped, switching from an operating state to a stopped state, thereby switching to BEV running using only the electric motor MG as a power source. In this way, in the vehicle 10, the engine 12 is switched from a stopped state to an operating state during BEV running to switch to HEV running, or the engine 12 is switched from an operating state to a stopped state during HEV running to switch to BEV running, thereby performing intermittent operation of the engine 12. This intermittent operation of the engine 12, in which the engine 12 is switched from an operating state to a stopped state during HEV running, is controlled by the electronic control unit 80 according to the vehicle state.

[0020] For example, a region where the vehicle speed V [km / h] is relatively low and the required drive torque Trdem [Nm] required of the vehicle 10 is relatively low is predetermined as the BEV driving region where the BEV driving mode is selected. A region where the vehicle speed V is relatively high or the required drive torque Trdem is relatively high is predetermined as the HEV driving region where the HEV driving mode is selected. Note that, for example, when the state of charge value SOC [%] of the battery supplying power to the electric motor MG (the ratio of the amount of charge actually stored to a predetermined full charge capacity) is lower than a predetermined state value or when the engine 12 needs to be warmed up, the BEV driving region may be changed to the HEV driving region. The predetermined state value is a predetermined judgment value for determining that the state of charge value SOC is such that the engine 12 needs to be forcibly started and the battery needs to be charged.

[0021] The vehicle 10 is equipped with an electronic control device 80 as a controller including a control device for the vehicle 10. The electronic control device 80 is configured to include 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 a program stored in advance in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 80 corresponds to the "control device" in the present invention.

[0022] The electronic control device 80 receives various signals based on detection values ​​from various sensors provided on the vehicle 10 (for example, an accelerator opening sensor 70, a brake operation amount sensor 72, a vehicle speed sensor 74, an engine rotation speed sensor 76, an electric motor rotation speed sensor 78, etc.) (for example, an accelerator opening θacc [%] which is the amount of accelerator operation by the driver that indicates the magnitude of the driver's acceleration operation, a driver's brake operation amount θbrk [%] which indicates the magnitude of the driver's deceleration operation, a vehicle speed V, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12 and has the same value as the rotation speed of one side of the make-and-break clutch K0, an electric motor rotation speed Nmg [rpm] which is the rotation speed of the electric motor MG and has the same value as the rotation speed of the other side of the make-and-break clutch K0, etc.). The electronic control device 80 corresponds to the "control device" in this invention.

[0023] The electronic control device 80 outputs various signals (e.g., an engine control signal Se for controlling the engine 12, an electric motor control signal Smg for controlling the drive of the electric motor MG, a brake control signal Sbrk for controlling the braking force of the brake device 40, a K0 control signal Sk0 for controlling the engagement and disengagement of the engagement and disengagement of the engagement and disengagement of the engagement and disengagement of the engagement and disengagement of the start clutch WSC, etc.) to each device provided in the vehicle 10 (e.g., an engine control device for controlling the engine 12, the inverter 30, the hydraulic control circuit 50, etc.).

[0024] Next, we will explain the control of the electronic control device 80 to determine whether or not the on-failure of the make-and-break clutch K0 is in a constantly engaged state when the vehicle transitions from the HEV driving state to the stopped state. "Always engaged" means that the make-and-break clutch K0 does not enter a released state regardless of the execution of the K0 release control described below.

[0025] FIG. 2 is a schematic diagram illustrating the rotational speeds of the engine 12, the electric motor MG, and the pair of drive wheels 14 in various states of the vehicle 10. (a) shows the HEV driving state, (b) shows the state in which the engine 12 is maintained in operation while the vehicle is stopped, (c) shows the state after the electric motor stop control is executed when the disconnecting clutch K0 is normal, (d) shows the state in which the engine 12 is stopped due to the execution of engine stop control when the disconnecting clutch K0 is normal, (e) shows the state at the start of driving in the BEV driving mode when the disconnecting clutch K0 is normal, (f) shows the state after the electric motor stop control is executed when the disconnecting clutch K0 has an on-failure, and (g) shows the state at the start of driving in the HEV driving mode when the disconnecting clutch K0 has an on-failure. The vertical axis in FIG. 2 represents rotational speed. In FIG. 2, three vertical lines Y1, Y2, and Y3, from left to right, represent the wheel speed Nw [rpm], which is the average rotational speed of the pair of drive wheels 14, the electric motor rotation speed Nmg, and the engine rotation speed Ne, respectively.

[0026] The main control operations of the electronic control unit 80 will be described below with reference to the functional blocks of the electronic control unit 80 shown in FIG. 1 and FIG.

[0027] The electronic control device 80 functionally includes a vehicle stop determination unit 82, an engine control unit 84, an electric motor control unit 86, a clutch control unit 88, a differential rotation determination unit 90, and an evacuation travel control unit 92. The engine control unit 84 functionally includes a start control unit 84a, a driving control unit 84b, and a stop control unit 84c.

[0028] The vehicle stop determination unit 82 determines whether the vehicle has transitioned from the HEV driving state to the stopped state. For example, if the vehicle speed V is lower than a predetermined determination vehicle speed V_jdg, it is determined that the vehicle is in the stopped state. The determination vehicle speed V_jdg is a vehicle speed value slightly greater than zero that is predetermined experimentally or by design in order to determine the stopped state. Before the vehicle 10 transitions to the stopped state, the clutch control unit 88 maintains execution of K0 engagement control, which keeps the on-off clutch K0 in an engaged state, and executes WSC release control, which keeps the starting clutch WSC in a released state. In the HEV driving state, as shown in FIG. 2(a), both the on-off clutch K0 and the starting clutch WSC are engaged, and the engine rotation speed Ne and the wheel speed Nw [rpm] are rotation speeds corresponding to the vehicle speed V.

[0029] When the vehicle stop determination unit 82 determines that the vehicle has transitioned from the HEV driving state to the stopped state, the engine control unit 84, the electric motor control unit 86, and the clutch control unit 88 prohibit intermittent operation of the engine 12 and prohibit switching from the HEV driving state to the BEV driving state. That is, automatic stopping of the engine 12 when the vehicle 10 is stopped is prohibited, and the engine 12 is maintained in an operating state. The operation control unit 84b of the engine control unit 84 maintains the engine 12 in an operating state to prevent engine stall. In this stopped state, as shown in FIG. 2(b), the engine 12 is maintained in an operating state, the disconnecting clutch K0 is engaged, and the starting clutch WSC is released. Therefore, the wheel speed Nw is zero, and the engine rotation speed Ne (= Nmg) is, for example, an idling rotation speed Ne_id.

[0030] When the vehicle stop determination unit 82 determines that the vehicle has transitioned from the HEV driving state to the stopped state, the clutch control unit 88 executes K0 release control to release the on-off clutch K0, and the electric motor control unit 86 executes electric motor stop control to stop the electric motor MG. The K0 release control corresponds to the "release control" in this invention. The electric motor stop control is, for example, control to prevent the inverter 30 from supplying a drive current for driving the electric motor MG. In this way, when the vehicle transitions from the HEV driving state to the stopped state, the engine 12 and the electric motor MG are not stopped simultaneously to improve the fuel efficiency of the engine 12 and the power efficiency of the electric motor MG, but rather only the electric motor MG is stopped first. In the execution of the K0 release control and the electric motor stop control, the on-off clutch K0 is controlled to be released as indicated by the solid arrow in FIG. 2(b), and the electric motor rotation speed Nmg is controlled to decrease as indicated by the hollow arrow in FIG. 2(b).

[0031] The differential rotation determination unit 90 determines whether the differential rotation ΔNk0 [rpm] of the disconnecting clutch K0 becomes equal to or greater than the determination value ΔNk0_jdg during a predetermined period T [sec] from the start of execution of the motor stop control when intermittent operation of the engine 12 is prohibited, i.e., whether the differential rotation ΔNk0 is less than the determination value ΔNk0_jdg during the predetermined period T from the start of execution of the motor stop control. The differential rotation ΔNk0 is the difference between the rotation speed of one side and the rotation speed of the disconnecting clutch K0, i.e., the difference between the engine rotation speed Ne and the electric motor rotation speed Nmg (=Ne-Nmg). The predetermined period T is a period determined experimentally or by design as the elapsed period during which the differential rotation ΔNk0 becomes equal to or greater than the determination value ΔNk0_jdg if the disconnecting clutch K0 is normal. The judgment value ΔNk0_jdg is a judgment value that is experimentally or design-defined as the differential rotation speed ΔNk0 that occurs in the disconnecting clutch K0 when the disconnecting clutch K0 is normal. If the disconnecting clutch K0 has an ON failure, the differential rotation speed ΔNk0 will be less than the judgment value ΔNk0_jdg even after the predetermined period T has elapsed since the start of execution of the motor stop control, and if the disconnecting clutch K0 is normal, the predetermined period T and the judgment value ΔNk0_jdg are set so that the differential rotation speed ΔNk0 will be equal to or greater than the judgment value ΔNk0_jdg within the predetermined period T from the start of execution of the motor stop control. The judgment value ΔNk0_jdg corresponds to the "predetermined judgment value" in this invention.

[0032] If the differential rotation determination unit 90 determines that the differential rotation speed ΔNk0 becomes equal to or greater than the reference value ΔNk0_jdg during the predetermined period T from the start of execution of the electric motor stop control, the stop control unit 84c executes engine stop control to stop the engine 12. When the disconnecting clutch K0 is normally released by executing the K0 release control, as shown in FIG. 2(c), the differential rotation speed ΔNk0 becomes equal to or greater than the reference value ΔNk0_jdg during the predetermined period T from the start of execution of the electric motor stop control. For example, when the electric motor rotation speed Nmg is zero while the engine rotation speed Ne is the idling rotation speed Ne_id, the differential rotation speed ΔNk0 becomes equal to or greater than the reference value ΔNk0_jdg. Execution of the engine stop control causes the engine 12 to be stopped, as shown in FIG. 2(d).

[0033] For example, when the vehicle is temporarily stopped at an intersection or the like and the engine 12 is stopped, and then the driver depresses the accelerator pedal 60 to start the vehicle, the vehicle starts traveling in the BEV traveling mode, and then intermittent operation of the engine 12 is performed as needed. In the intermittent engine operation, the start of the engine 12 is controlled by the start control unit 84a, and the stop of the engine 12 is controlled by the stop control unit 84c. When the vehicle starts traveling in the BEV traveling mode, the starting clutch WSC changes from a released state to a slip-engagement state (see FIG. 2(e)) and then to a fully engaged state, whereby the MG torque Tmg is transmitted from the electric motor MG to the pair of drive wheels 14, and the wheel speed Nw increases as the electric motor rotation speed Nmg increases. Note that, compared to when the on-state of the disconnecting clutch K0 is faulty, when the disconnecting clutch K0 is normal, the electric motor MG does not drag the engine 12 at the time of starting the vehicle. Therefore, the electric motor MG only needs to output power for traveling, and traveling in the BEV traveling mode can be easily started.

[0034] If the differential rotation determination unit 90 determines that the differential rotation ΔNk0 is less than the determination value ΔNk0_jdg from the start of execution of the electric motor stop control until the predetermined period T has elapsed, the evacuation travel control unit 92 determines that the disconnection clutch K0 has an ON failure. If the disconnection clutch K0 remains engaged due to an ON failure regardless of execution of the K0 release control, the electric motor rotation speed Nmg and the engine rotation speed Ne will be equal to each other, as shown in FIG. 2(f). Therefore, the differential rotation ΔNk0 will be less than the determination value ΔNk0_jdg from the start of execution of the electric motor stop control until the predetermined period T has elapsed.

[0035] When the evacuation travel control unit 92 determines that the disconnecting clutch K0 has an on-failure, the evacuation travel control unit 92 controls the vehicle 10 to perform evacuation travel in HEV traveling mode. For example, since the engine 12 remains in operation even when the vehicle is temporarily stopped at an intersection, the evacuation travel control unit 92 starts the vehicle 10 in HEV traveling mode when starting the vehicle 10. When starting to travel in HEV traveling mode, the starting clutch WSC transitions from a released state to a slip-engaged state (see FIG. 2(g)) and then to a fully engaged state, thereby transmitting power from the engine 12 and the electric motor MG to the pair of drive wheels 14. As a result, the wheel speed Nw increases as the engine rotation speed Ne and the electric motor rotation speed Nmg increase. Since the engine 12 remains in operation even when the disconnecting clutch K0 has an on-failure, evacuation travel can be started more easily using the HEV traveling mode than when the engine 12 is stopped. After the vehicle 10 has been driven to a safe location by the evacuation drive, the engine 12 is stopped by turning off the start switch while the vehicle is stopped, for example.

[0036] Fig. 3 is an example of a flowchart illustrating the main control operations of the electronic control device 80 shown in Fig. 1. The flowchart in Fig. 3 is executed during HEV driving (particularly immediately before the vehicle speed V decreases and the vehicle comes to a stop).

[0037] First, in step S10 (hereinafter, step will be omitted) corresponding to the function of the vehicle stop determination unit 82, it is determined whether or not the vehicle has transitioned from the HEV driving state to the stopped state.

[0038] If the determination in S10 is NO, the process of S10 is executed again. If the determination in S10 is YES, the intermittent operation of the engine 12 is prohibited in S20, which corresponds to the functions of the engine control unit 84, the electric motor control unit 86, and the clutch control unit 88.

[0039] After the process of S20 is executed, in S30 corresponding to the functions of the electric motor control unit 86 and the clutch control unit 88, electric motor stop control and K0 release control are executed.

[0040] After the process of S30 is executed, in S40 corresponding to the function of the differential rotation determining unit 90, it is determined whether the differential rotation ΔNk0 is equal to or greater than the determination value ΔNk0_jdg.

[0041] If the determination in S40 is YES, engine stop control is executed in S50, which corresponds to the function of the stop control unit 84c. After the process of S50 is executed, the process of the flowchart ends.

[0042] If the determination in S40 is NO, then in S60, which corresponds to the function of the differential rotation determination unit 90, it is determined whether or not a predetermined period T has elapsed. If the determination in S60 is NO, the processing of S40 is executed again. If the determination in S60 is YES, then in S70, which corresponds to the function of the evacuation travel control unit 92, it is determined that the disconnection clutch K0 has an ON failure.

[0043] After the process of S70 is executed, in S80, which corresponds to the function of the evacuation travel control unit 92, control is executed to maintain the operating state of the engine 12 and enable evacuation travel in the HEV travel mode. After the process of S80 is executed, the process of the flowchart ends.

[0044] According to this embodiment, (a) when the vehicle transitions from an HEV driving state to a stopped state, the operating state of the engine 12 is maintained, release control is executed to release the disconnecting clutch K0, and electric motor stop control is executed to stop the electric motor MG, (b) if the differential rotation speed ΔNk0 becomes equal to or greater than the determination value ΔNk0_jdg from the start of execution of the electric motor stop control until the predetermined period T has elapsed, engine stop control is executed, and (c) if the differential rotation speed ΔNk0 is less than the determination value ΔNk0_jdg from the start of execution of the electric motor stop control until the predetermined period T has elapsed, it is determined that the disconnecting clutch K0 has an on-failure. When the vehicle transitions from an HEV driving state to a stopped state, the operating state of the engine 12 is maintained while the electric motor MG is stopped, so that an on-failure of the disconnecting clutch K0 can be detected.

[0045] According to this embodiment, when it is determined that the disconnecting clutch K0 has an on-failure, the operating state of the engine 12 is maintained and control is performed to enable evacuation traveling in the HEV traveling mode when starting from a stopped state. As a result, evacuation traveling in the HEV mode can be easily initiated when starting from a stopped state, compared to when the operating state of the engine 12 is not maintained and the engine 12 is stopped. Specifically, the vehicle 10 can be started in a state in which deterioration of drivability, such as acceleration performance at start and NV (Noise Vibration) performance, is suppressed, compared to when starting using the power of the electric motor MG while dragging the engine 12.

[0046] 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.

[0047] In the above-described embodiment, the motor stop control is a control that prevents the drive current for driving the motor MG from flowing from the inverter 30, but is not limited to this. For example, the motor stop control may be a control that applies a braking torque to the motor MG to an extent that engine stall does not occur even if the motor MG and the engine 12 are in a directly coupled state due to an ON fault of the disconnecting clutch K0.

[0048] In the above-described embodiment, the electric motor MG is a so-called motor generator, but for example, the electric motor MG may be a rotating electric machine that does not have a generator function but has only a motor function.

[0049] In the above-described embodiment, the vehicle 10 is provided with a starting clutch WSC between the electric motor MG and the differential 18 in the power transmission path PT, but this is not limiting. For example, a fluid-type power transmission device such as a torque converter or a fluid coupling may be provided instead of the starting clutch WSC.

[0050] It should be noted that the above is merely an example of the present invention, 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, without departing from the spirit of the present invention. [Explanation of symbols]

[0051] 10: vehicle, 12: engine, 80: electronic control device (control device), K0: disconnecting clutch, MG: electric motor, T: predetermined period, ΔNk0: differential rotation, ΔNk0_jdg: judgment value (predetermined judgment value)

Claims

1. A control device for a vehicle including an engine and an electric motor as power sources, and a disconnecting clutch that connects and disconnects power transmission between the engine and the electric motor, When the vehicle changes from a running state using the engine as a power source to a stopped state, the operating state of the engine is maintained, a release control is executed to release the disconnecting clutch, and an electric motor stop control is executed to stop the electric motor, When the differential rotation of the connecting / disconnecting clutch becomes equal to or greater than a predetermined judgment value during a predetermined period from the start of execution of the electric motor stop control, an engine stop control is executed to stop the engine. If the differential rotation is less than the determination value from the start of execution of the electric motor stop control until the predetermined period has elapsed, it is determined that the disconnecting clutch is in a constantly engaged state, i.e., an on-failure has occurred. A vehicle control device characterized by:

2. When it is determined that the disconnecting clutch has the on-failure, the engine is maintained in an operating state, and when the vehicle starts from the stopped state, control is performed to enable evacuation running using the engine as a power source.

2. The vehicle control device according to claim 1.

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