Travel drive control device for vehicle

Abstract

A travel drive control device 1 for a vehicle has: an engine 2 that drives a travel drive wheel of the vehicle via a first power transmission path 11; a motor 4 that drives the travel drive wheel via a second power transmission path 12 different from the first power transmission path 11; an engine clutch 7a that is capable of connecting / disconnecting the first power transmission path 11; and a motor clutch 7b that is capable of connecting / disconnecting the second power transmission path 12, the travel drive control device 1 performing operation control for the engine clutch 7, the motor clutch 7b, the engine 2, and the motor 4 on the basis of a parameter such as the vehicle speed. The travel drive control device 1 is provided with a hybrid control unit 30 that outputs, if a failure in the motor clutch 7b is detected during a parallel mode, the drive force of the engine 2 to a drive shaft 8 while maintaining engagement of the engine clutch 7a irrespective of a change in the parameter.

Description

Travel drive control device for a vehicle

[0001] The present invention relates to a travel drive control device for a hybrid vehicle.

[0002] Conventionally, in a plug-in hybrid vehicle or a hybrid vehicle (hereinafter collectively referred to as a hybrid vehicle) equipped with an engine and an electric motor as travel drive sources, vehicles capable of switching travel modes have been developed. Known travel modes include an EV mode in which only an electric motor drives for travel, a series mode in which an electric motor and an engine drive for travel, and a parallel mode.

[0003] For example, the vehicle described in Patent Document 1 includes a clutch (engine clutch) in the power transmission path between the engine and the travel drive wheels. By releasing the engine clutch, a series mode is enabled in which the generator is driven by the engine to generate electricity while the vehicle is driven by the motor. On the other hand, in the above-described vehicle, by engaging the engine clutch, a parallel mode is enabled in which the vehicle is driven by the engine while the driving force is assisted by the motor.

[0004] Further, Patent Document 1 describes a vehicle equipped with a motor clutch (motor clutch) in the power transmission path between the motor and the travel drive wheels. In the above-described vehicle, by releasing the motor clutch, it becomes possible to stop driving the motor while driving the vehicle by the engine.

[0005] The engine clutch, motor clutch, etc. automatically switch based on the vehicle speed, the required driving torque of the vehicle, etc.

[0006] WO2020 / 148973 / A1

[0007] By the way, in recent years, the importance of fail-safe has been increasing. For example, in a vehicle equipped with a motor clutch and an engine clutch as described above, the running performance in the case of an abnormality such as a malfunction of the clutch is required. In particular, when the motor clutch becomes fixed in the open state during travel in the parallel mode, it may become difficult to perform emergency evacuation travel.

[0008] This invention has been made in view of the above problems, and its objective is to provide a vehicle drive control device that enables the vehicle to move in an emergency position in the event of a motor clutch failure in a hybrid vehicle equipped with a motor clutch and an engine clutch.

[0009] To achieve the above objective, the vehicle driving control device of the present invention comprises: an engine that drives the vehicle's driving wheels via a first power transmission path; a motor that drives the driving wheels via a second power transmission path different from the first power transmission path; an engine clutch provided in the first power transmission path that can disconnect and reconnect power transmission between the engine and the drive shaft of the driving wheels; a motor clutch provided in the second power transmission path that can disconnect and reconnect power transmission between the motor and the drive shaft; and a parameter acquisition unit that acquires parameters relating to the driving state of the vehicle, and the vehicle driving control device controls the operation of the engine clutch, the motor clutch, the engine and the motor based on the parameters, and further comprises: a clutch failure detection unit that detects a failure of the motor clutch; and a driving control unit that, when a failure of the motor clutch is detected while the engine clutch is engaged, executes an engine driving continuation process that outputs the driving force of the engine to the drive shaft regardless of the parameters.

[0010] The vehicle drive control device of the present invention allows the vehicle to be driven by the engine's driving force regardless of the parameters if a motor clutch failure is detected while the engine clutch is engaged. This makes it possible to move the vehicle to a safer position regardless of parameter changes in the event of a motor clutch failure, thereby enhancing safety.

[0011] This is a diagram showing the configuration of the drive system of a vehicle equipped with a drive control device according to an embodiment of the present invention. This is a part of a flowchart showing an example of the control procedure for motor clutch failure. This is the remainder of the flowchart showing an example of the control procedure for motor clutch failure. This is a part of a flowchart showing an example of the control procedure for engine clutch failure. This is the remainder of the flowchart showing an example of the control procedure for engine clutch failure. This is an explanatory diagram showing the control content for motor clutch failure.

[0012] Embodiments of the present invention will be described below with reference to the drawings.

[0013] Figure 1 is a diagram showing the configuration of the drive system of a vehicle employing a drive control device according to one embodiment of the present invention.

[0014] The driving control device of this embodiment is applied to vehicles equipped with an engine and a motor as a driving source, such as plug-in hybrid vehicles (PHEVs) and hybrid vehicles that can be charged and supplied with external power.

[0015] As shown in Figure 1, the vehicle equipped with the driving control device 1 of this embodiment is capable of driving by driving the drive wheels (for example, the front wheels) with the output of the engine 2, and is also equipped with an electric motor 4 that drives the drive wheels.

[0016] The engine 2 is capable of driving the drive shaft 8 of the drive wheels via the reduction gear 7, and is also capable of driving the motor generator 9 via the reduction gear 7 to generate electricity.

[0017] Motor 4 is powered by high-voltage electricity supplied from a drive battery (not shown) and a motor generator 9 mounted on the vehicle, and drives the drive shaft 8 via a reduction gear 7. In the reduction gear 7, the first power transmission path 11, which is the power transmission path between the engine 2 and the drive shaft 8, and the second power transmission path 12, which is the power transmission path between motor 4 and the drive shaft 8, are separate paths. The motor generator 9 is also powered by receiving power from the engine 2 via a third power transmission path.

[0018] The reduction gear 7 incorporates an engine clutch 7a that can switch the transmission of power in the first power transmission line 11 on and off. The reduction gear 7 also incorporates a motor clutch 7b that can switch the transmission of power between it and the second power transmission line 12 on and off.

[0019] The engine clutch 7a is driven by an electric engine clutch actuator 21 and can switch the first power transmission path 11 between connected and disconnected states. When the clutch is engaged (connected), it can also switch the reduction ratio in the first power transmission path 11 between two levels (high gear and low gear).

[0020] The motor clutch 7b is driven by an electric motor clutch actuator 22 and is capable of switching the second power transmission path 12 on and off.

[0021] The engine clutch actuator 21 and the motor clutch actuator 22 are driven and controlled by a hybrid control unit 30 (driving control unit, determination unit, clutch failure detection unit) via a transmission control unit 25 mounted on the vehicle.

[0022] The power generated by the motor generator 9 can charge a drive battery (not shown) mounted on the vehicle and also supply power to the motor 4. The drive battery is equipped with a battery monitoring unit 35 that monitors the charge level (State of Charge, hereinafter referred to as SOC), etc.

[0023] Furthermore, the vehicle is equipped with a notification unit 36 ​​that notifies the driver of a malfunction in the motor clutch 7b and the engine clutch 7a. The notification unit 36 ​​can be any device that can notify the driver, for example, through a display on the vehicle's control panel or by sound.

[0024] The hybrid control unit 30 is a control device for comprehensively controlling the vehicle and includes input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), and the like. The transmission control unit 25 is a control device for controlling the engine clutch 7a and motor clutch 7b as described above and includes input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), and the like.

[0025] The hybrid control unit 30 has the transmission control unit 25, battery monitoring unit 35, engine control unit 37 for driving and controlling engine 2, accelerator opening sensor 40 for detecting accelerator operation, and vehicle speed sensor 43 (parameter acquisition unit) for detecting vehicle speed connected to its input side. The hybrid control unit 30 receives detection information and operation information from these devices as input.

[0026] Furthermore, the hybrid control unit 30 has the transmission control unit 25, engine control unit 37, motor 4, motor generator 9, etc., connected to its output side.

[0027] Furthermore, the hybrid control unit 30 calculates the vehicle's required output for driving the vehicle and the driving torque based on the various detected quantities and operating information from the accelerator opening sensor 40 and other sensors. The hybrid control unit 30 then transmits control signals to the engine control unit 37, motor 4, motor generator 9, transmission control unit 25, etc. The hybrid control unit 30 switches between driving modes (EV mode: electric vehicle mode, series mode, and parallel mode), controls the output of the engine 2 and motor 4, and controls the output (generated power) of the motor generator 9.

[0028] In EV mode, the hybrid control unit 30 stops the engine 2, disengages the engine clutch 7a of the reduction gear 7, engages the motor clutch 7b, and drives the motor 4 with power supplied from the drive battery to move the vehicle.

[0029] In series mode, the hybrid control unit 30 disengages the engine clutch 7a of the reduction gear 7 and engages the motor clutch 7b, driving the motor generator 9 with the engine 2. The hybrid control unit 30 then drives the motor 4 with the power generated by the motor generator 9 and the power supplied from the drive battery to move the vehicle. In series mode, the hybrid control unit 30 also sets the rotational speed of the engine 2 to a predetermined speed and supplies surplus power to the drive battery to charge it.

[0030] In parallel mode, the hybrid control unit 30 engages the engine clutch 7a of the reduction gear 7, mechanically transmitting power from the engine 2 to the drive shaft 8 via the reduction gear 7 to drive the drive wheels. The hybrid control unit 30 also drives the motor 4 with electricity generated by the motor generator 9 operated by the engine 2 and electricity supplied from the drive battery to move the vehicle.

[0031] The hybrid control unit 30 sets the driving mode to parallel mode in areas where the engine 2 is efficient, such as high speeds. In areas other than parallel mode, i.e., in the medium to low speed range, the hybrid control unit 30 switches the driving mode between EV mode and series mode based on the vehicle's driving torque and the state of charge (SOC) of the drive battery.

[0032] Furthermore, in parallel mode, the hybrid control unit 30 switches the engine clutch 7a to high gear or low gear based on the vehicle speed V. For example, in parallel mode, the hybrid control unit 30 sets the engine clutch 7a to a high gear with a low reduction ratio when the vehicle speed V is above a predetermined speed set appropriately, and sets the engine clutch 7a to a low gear with a high reduction ratio when the vehicle speed V is below a predetermined speed set appropriately.

[0033] Furthermore, in parallel mode, the hybrid control unit 30 releases the motor clutch 7b when the requested output becomes, for example, 0 or less. This allows the hybrid control unit 30 to suppress the forced driving of the motor 4 in conjunction with the rotation of the drive wheels when the output of the motor 4 is not needed, thereby improving the vehicle's fuel efficiency.

[0034] The engine clutch 7a is equipped with an engine clutch stroke sensor 45 that detects the clutch stroke of the engine clutch 7a. The motor clutch 7b is equipped with a motor clutch stroke sensor 46 that detects the clutch stroke of the motor clutch 7b. The detected values ​​from the engine clutch stroke sensor 45 and the motor clutch stroke sensor 46 are input to the transmission control unit 25.

[0035] <Motor Clutch Failure Control> The hybrid control unit 30 performs motor clutch failure control to enable the vehicle to move in the event of a motor clutch failure 7b failure. Note that the motor clutch failure control may also be performed by the transmission control unit 25.

[0036] Figures 2 and 3 are flowcharts showing an example of a control procedure for motor clutch failure control.

[0037] The control shown in Figures 2 and 3 is repeatedly executed at predetermined intervals (e.g., several msec) while the vehicle is in motion (for example, when the vehicle speed V is greater than 0 km / h).

[0038] First, as shown in Figure 2, the hybrid control unit 30 determines whether the value of the failsafe flag F1 is 1 (step S10). In this step, the value of the failsafe flag F1 is set to 0 when the vehicle power is turned on or after a clutch failure is repaired at a repair shop, etc., and is set to 1 in step S30, which will be described later, when a motor clutch fails.

[0039] When the hybrid control unit 30 determines that the value of the fail-safe flag F1 is 0, it determines whether or not the motor clutch 7b has failed (step S20). Specifically, the hybrid control unit 30 determines whether there are any electrical or functional failures in the various components and sensors that make up the motor clutch 7b. The presence or absence of an electrical failure is determined, for example, by whether or not a failure signal has been input from the various components and sensors. This allows the hybrid control unit 30 to accurately determine if the motor clutch 7b has failed. The presence or absence of a functional failure is determined, for example, by whether or not the input value from the sensors that make up the motor clutch 7b has changed abruptly in a short period of time that has been appropriately set. This allows the hybrid control unit 30 to determine if the motor clutch 7b has failed earlier than it could have determined if there was an electrical failure, and to transition to fail-safe mode sooner.

[0040] If the hybrid control unit 30 determines that the motor clutch 7b is malfunctioning, it sets the value of the failsafe flag F1 related to the motor clutch 7b to 1 (step S30).

[0041] Next, the hybrid control unit 30 controls the notification unit 36 ​​to start notifying the driver that the motor clutch 7b has malfunctioned (step S40).

[0042] In step S10, the hybrid control unit 30 determines that the value of the failsafe flag F1 is 1, or performs the processing in step S40, and then determines whether the motor clutch 7b is in an open state based on the value detected by the motor clutch stroke sensor 46 (step S50).

[0043] When the hybrid control unit 30 determines that the motor clutch 7b is in the released state, it acquires the current driving mode set based on the vehicle speed V, required output, etc. (step S60).

[0044] Subsequently, the hybrid control unit 30 determines whether the current driving mode is the parallel mode (step S70).

[0045] As shown in FIG. 3, when the hybrid control unit 30 determines that the current driving mode is the parallel mode, it acquires the current vehicle speed V from the vehicle speed sensor 43 (step S80).

[0046] Then, the hybrid control unit 30 determines whether the vehicle speed V is less than the minimum speed at which the vehicle can travel in the parallel mode (hereinafter referred to as the parallel minimum speed Vp) (step S90). The parallel minimum speed Vp corresponds to the engine running lower limit speed of the present invention at which the vehicle speed V corresponds to the lower limit rotation speed of the engine 2 in the parallel mode.

[0047] When the hybrid control unit 30 determines that the vehicle speed V is less than the parallel minimum speed Vp, it controls the engine clutch actuator 21 to release the engine clutch 7a and terminate the parallel mode (step S100). As a result, the driving mode of the vehicle shifts to a driving mode other than the parallel mode (series mode or EV mode) based on the vehicle speed V, required output, etc. as described above.

[0048] After the hybrid control unit 30 determines in step S70 that the driving mode of the vehicle is not the parallel mode, it stops the running of the vehicle (step S130). The driving mode of the vehicle is a driving mode other than the parallel mode (series mode or EV mode). Therefore, the hybrid control unit 30 can stop the running of the vehicle by, for example, setting the output of the motor 4 to the value 0.

[0049] As shown in Figure 2, the hybrid control unit 30 determines in step S50 that the motor clutch is not in the disengaged state (it is in the engaged state), and then prohibits the disengagement of the motor clutch 7b to maintain the engaged state (step S140).

[0050] If the hybrid control unit 30 determines in step S20 that the motor clutch 7b is not malfunctioning, it updates the driving mode (step S150). That is, the hybrid control unit 30 updates the driving mode to one set based on the vehicle speed V, the requested output, etc.

[0051] The hybrid control unit 30 determines in step S90 that the vehicle speed V is equal to or greater than the parallel minimum speed Vp, or performs one of the processes in steps S100, S130, S140, and S150, and then returns to this routine.

[0052] The hybrid control unit 30 performs motor clutch failure control as shown in Figures 2 and 3. If it determines that the motor clutch 7b has failed while the vehicle is running (YES in step S20 shown in Figure 2), it sets the value of the failsafe flag F1 to 1 (step S30) and notifies the driver that the motor clutch 7b has failed (step S40).

[0053] Then, the hybrid control unit 30 determines that the motor clutch 7b is faulty (YES in step S20), and if it further determines that the motor clutch 7b is not in an open state (is in a connected state) (NO in step S50), it restricts the switching of the driving mode by prohibiting the opening of the motor clutch 7b (step S140).

[0054] When the hybrid control unit 30 determines that the motor clutch 7b is faulty (YES in step S20), and the motor clutch 7b is in an open state (YES in step S50), and the driving mode is series mode or EV mode as shown in Figure 3 (NO in step S70), it stops the vehicle from driving (step S130).

[0055] If the driving mode is parallel mode (YES in step S70), the hybrid control unit 30 releases the engine clutch 7a (step S100) after the vehicle speed V has decreased to the minimum parallel speed Vp (steps S80 and S90). As a result, the engine 2 enables low-speed driving until the vehicle speed V decreases to the minimum parallel speed Vp.

[0056] Furthermore, if the fail-safe flag F1 is set to 1 due to a motor clutch 7b failure, it will remain at 1 until the vehicle power is switched from OFF to ON or set to 0 at a repair shop or similar location. This ensures that once a motor clutch 7b failure is detected, further failure detection of the motor clutch 7b is unnecessary, at least until the vehicle comes to a stop.

[0057] <Engine Clutch Failure Control> The hybrid control unit 30 also performs engine clutch failure control to enable the vehicle to move in the event of a failure of the engine clutch 7a. Note that the engine clutch failure control may also be performed by the transmission control unit 25.

[0058] Figures 4 and 5 are flowcharts showing an example of a control procedure for engine clutch failure control.

[0059] The engine clutch failure control is repeatedly executed at predetermined intervals (e.g., several msec) while the vehicle is in motion (e.g., when the vehicle speed V is greater than 0 [km / h]).

[0060] First, as shown in Figure 4, the hybrid control unit 30 determines whether the value of the failsafe flag F2 is 1 (step S210). In this step, the value of the failsafe flag F2 is set to 0 when the vehicle power is turned on or after a clutch failure is repaired at a repair shop, etc., and is set to 1 in step S230, which will be described later, when an engine clutch failure occurs.

[0061] When the hybrid control unit 30 determines that the value of the fail-safe flag F2 is 0, it determines whether or not the engine clutch 7a is malfunctioning (step S220). The hybrid control unit 30 determines whether or not the engine clutch 7a is malfunctioning by performing the same processing as in step S20 of the driving process shown in Figure 2.

[0062] If the hybrid control unit 30 determines that the engine clutch 7a is malfunctioning, it sets the value of the failsafe flag F2 related to the engine clutch 7a to 1 (step S230).

[0063] Next, the hybrid control unit 30 controls the notification unit 36 ​​to start notifying the driver that the engine clutch 7a has malfunctioned (step S240).

[0064] In step S210, the hybrid control unit 30 determines that the value of the failsafe flag F2 is 1, and after executing the process in step S240, it obtains the current driving mode set based on the vehicle speed V and the requested output, and determines whether or not the vehicle's driving mode is parallel mode (step S250).

[0065] When the hybrid control unit 30 determines that the current driving mode is parallel mode, it controls the engine clutch actuator 21 to release the engine clutch 7a and end the parallel mode (step S260). As a result, the vehicle's driving mode will switch to series mode or EV mode based on the vehicle speed V, requested output, etc., as described above.

[0066] Next, the hybrid control unit 30 updates the driving mode (step S270). That is, the hybrid control unit 30 updates the vehicle's driving mode from parallel mode to series mode or EV mode.

[0067] After determining in step S250 that the vehicle's driving mode is not parallel mode, the hybrid control unit 30 determines whether or not the engine clutch 7a is in an open state based on the value detected by the engine clutch stroke sensor 45 (step S280).

[0068] When the hybrid control unit 30 determines that the engine clutch 7a is not in the disengaged state, it determines that the engine clutch 7a is stuck and, as shown in Figure 5, terminates the series mode and commands the engine control unit 37 to make the engine torque Te equal to the friction torque Tf (in this embodiment, torque 0 [Nm] or less) (step S290). Upon receiving the command, the engine control unit 37 controls the engine 2 to make the engine torque Te equal to or less than the friction torque Tf (stops it).

[0069] Next, the hybrid control unit 30 obtains the engine torque Te from the engine control unit 37 (step S300). Subsequently, the hybrid control unit 30 obtains the current vehicle speed V from the vehicle speed sensor 43 (step S310). Then, the hybrid control unit 30 determines whether the engine torque Te is less than or equal to the lower limit torque (in this embodiment, torque 0 [Nm]) (S320).

[0070] If the hybrid control unit 30 determines that the engine torque Te is below the lower limit torque, it determines whether the vehicle speed V is below the upper limit vehicle speed Vf in case of failure (in this embodiment, a speed of 20 [km / h]) (step S330). If the hybrid control unit 30 determines that the vehicle speed V is below the upper limit vehicle speed Vf in case of failure, it performs driving with the motor 4 up to the upper limit vehicle speed Vf in case of failure (in this embodiment, a speed of 20 [km / h]) (step S340).

[0071] If the hybrid control unit 30 determines in step S320 that the engine torque Te is greater than the lower limit torque (in this embodiment, torque 0 [Nm]), it controls the amount of power generated by the motor generator 9 (GEN) to offset the engine torque Te (step S350). By controlling the motor generator 9 in this way, the hybrid control unit 30 controls the deceleration of the rotational speed of the engine 2.

[0072] The hybrid control unit 30 determines in step S330 that the vehicle speed V is less than or equal to the upper limit vehicle speed Vf in case of failure (in this embodiment, a speed of 20 [km / h] or less), or after executing the process in step S350, controls the motor 4 so that the motor torque Tm becomes 0 [Nm], thereby decelerating the vehicle.

[0073] As shown in Figure 4, if the hybrid control unit 30 determines in step S280 that the engine clutch 7a is in an open state, it disables parallel mode (step S370). In other words, even if conditions for selecting parallel mode are met due to changes in vehicle speed V or requested output, the hybrid control unit 30 does not switch the vehicle's driving mode to parallel mode, but maintains series mode or EV mode.

[0074] If the hybrid control unit 30 determines in step S220 that the engine clutch 7a is not malfunctioning, it updates the driving mode (step S380). In other words, if the hybrid control unit 30 determines that the engine clutch 7a is not malfunctioning, it updates the vehicle's driving mode to a driving mode set based on the vehicle speed V, requested output, etc.

[0075] The hybrid control unit 30 returns this routine after performing one of the processes in steps S270, S340, S360, S370, or S380.

[0076] The hybrid control unit 30, by executing the engine clutch failure control shown in Figures 4 and 5, determines that the engine clutch 7a has failed while the vehicle is in motion (YES in step S220), sets the value of the failsafe flag F2 to 1 (step S230), and notifies the driver that the engine clutch 7a has failed (step S240).

[0077] Furthermore, the hybrid control unit 30 determines that the engine clutch 7a is faulty (YES in step S220), and if the driving mode is parallel mode (YES in step S250), it terminates the parallel mode (step S260).

[0078] Furthermore, if the hybrid control unit 30 determines that the engine clutch 7a is faulty (YES in step S220), that the driving mode is series mode or EV mode (NO in step S250), and that the engine clutch 7a is disengaged (YES in step S280), it prohibits parallel mode (step S370). As a result, the vehicle's driving mode is maintained in series mode or EV mode.

[0079] Then, the hybrid control unit 30 determines that the engine clutch 7a is faulty (YES in step S220), that it is not in parallel mode (NO in step S250), and that the engine clutch 7a is not disengaged (NO in step S280). At that point, it determines that the driving mode is series mode and terminates the series mode, reducing the engine torque Te to friction torque Tf (step S290).

[0080] Furthermore, if the engine torque Te value becomes 0 [Nm] or less (YES in step S320), and the vehicle speed V is less than or equal to the maximum vehicle speed Vf in case of failure (YES in step S330), the hybrid control unit 30 executes a motor driving continuation process that drives the vehicle using the maximum vehicle speed Vf in case of failure as the upper limit (step S340).

[0081] Furthermore, if the engine torque Te exceeds 0 [Nm] (YES in step S320), the hybrid control unit 30 controls the amount of power generated by the motor generator 9 to offset the engine torque Te (step S350), thereby quickly setting the motor torque Tm to 0 [Nm] and decelerating the vehicle (step S360).

[0082] Furthermore, the hybrid control unit 30 sets the motor torque Tm to 0 [Nm] to decelerate the vehicle (S360) even when the engine torque Te is 0 [Nm] or less (YES in S320) and the vehicle speed V exceeds the upper limit vehicle speed Vf in case of failure.

[0083] Furthermore, if the fail-safe flag F2 is set to 1 due to a motor clutch 7b failure, it will remain at 1 until the vehicle power is switched from OFF to ON or set to 0 at a repair shop or similar location. This ensures that once a failure of the engine clutch 7a is detected, further failure detection of the engine clutch 7a is unnecessary, at least until the vehicle comes to a stop.

[0084] <Operation of Motor Clutch Failure Control> Figure 6 is an explanatory diagram showing the control content of motor clutch failure control, and shows the driving control content when the motor clutch 7b is functioning normally and when it fails during parallel driving.

[0085] As shown in Figure 6, the motor clutch 7b is in an open state when the vehicle's driving mode is parallel mode, both under normal conditions and in the event of a malfunction. The engine clutch 7a is in an engaged state when the vehicle's driving mode is parallel mode.

[0086] Under normal conditions, the motor clutch 7b engages in response to a decrease in vehicle speed V or a change in the required output. Furthermore, the engine clutch 7a is released based on a decrease in vehicle speed V or a change in the required output, i.e., a change in parameters related to the driving state. In this way, the vehicle's driving mode transitions from parallel mode to series mode or EV mode.

[0087] On the other hand, in the event of a malfunction, the motor clutch 7b remains open regardless of changes in parameters related to the driving state until the vehicle speed V reaches the parallel minimum speed. The engine clutch 7a is then released when the vehicle speed V reaches the parallel minimum speed.

[0088] As described above, in this embodiment, if a malfunction of the motor clutch 7b is detected during driving, the hybrid control unit 30 prohibits the disengagement of the motor clutch 7b if the motor clutch 7b is engaged. That is, if the hybrid control unit 30 is determined to be in parallel mode, where the engine clutch 7a is engaged, based on parameters such as the vehicle's driving speed, and a malfunction of the motor clutch 7b is detected, it executes an engine driving continuation process that engages the engine clutch 7a and outputs the driving force of the engine 2 to the drive shaft 8, regardless of subsequent parameter changes.

[0089] Thus, even if the hybrid control unit 30 attempts to engage the motor clutch 7b based on a change in parameters related to the vehicle's driving state, if it is unable to engage the motor clutch 7b due to a malfunction, it maintains the engaged state of the engine clutch 7a without updating the driving mode, even if the parameters become such that the engine clutch 7a should be released. In other words, the hybrid control unit 30 performs an engine driving continuation process that continues to transmit the driving force of the engine 2 to the drive shaft 8, so that it is possible to move the vehicle to a safe location using engine drive, thereby enhancing safety.

[0090] Furthermore, the hybrid control unit 30 prohibits the disengagement of the motor clutch 7b if a malfunction of the motor clutch 7b is detected while the motor clutch 7b is engaged, and executes the process of continuing engine operation if a malfunction of the motor clutch 7b is detected while the motor clutch 7b is disengaged.

[0091] This prevents the motor clutch 7b from being released, thereby avoiding control errors and other malfunctions that may occur when attempting to release a faulty motor clutch 7b, and enabling the vehicle to move in a safe position.

[0092] Furthermore, if the hybrid control unit 30 detects a failure in the motor clutch 7b and the engine clutch 7a is not engaged in a non-parallel mode (series mode or EV mode), it stops the engine 2 and motor 4 to stop the vehicle from moving. This allows the vehicle to coast to safety.

[0093] Furthermore, while the hybrid control unit 30 is executing the engine running continuation process, if the vehicle speed V falls below the parallel minimum speed Vp, it controls the engine clutch actuator 21 to release the engine clutch 7a. This prevents the engine from stopping while the engine clutch 7a is engaged, allowing for a smooth transition from coasting to a complete stop.

[0094] Furthermore, when a malfunction of the motor clutch 7b is detected, the hybrid control unit 30 notifies the driver of the malfunction via the notification unit 36, allowing the driver to easily recognize the malfunction of the motor clutch 7b and prompting them to take evasive action.

[0095] Furthermore, as shown in Figures 4 and 5, if a malfunction of the engine clutch 7a is detected while the vehicle is in motion, the hybrid control unit 30 will not update the driving mode and will prohibit the disengagement of the motor clutch 7b if the engine clutch 7a is in an open state. In other words, even if the system determines to be in parallel mode, which is to disengage the motor clutch 7b based on parameters related to the vehicle's driving state, the unit will maintain the engagement of the motor clutch 7b. In addition, the hybrid control unit 30 performs a motor driving continuation process that continues to transmit the driving force of the motor 4 to the drive shaft, enabling evasive driving by the motor 4 and further enhancing safety in more failure scenarios.

[0096] This concludes the description of the embodiments, but the embodiments of the present invention are not limited to those described above. For example, the engine clutch 7a in the above embodiment allows switching of the reduction ratio between high gear and low gear, but it may also be a clutch that allows switching of the reduction ratio between three or more stages, or a clutch that only allows switching between connecting and disconnecting without switching of the reduction ratio.

[0097] Furthermore, the present invention can be applied to the front-wheel drive unit or the rear-wheel drive unit in front-wheel drive vehicles, rear-wheel drive vehicles, or four-wheel drive vehicles.

[0098] 1. Driving control device 2. Engine 4. Motor 7b. Motor clutch 7a. Engine clutch 8. Drive shaft 11. First power transmission path 12. Second power transmission path 30. Hybrid control unit (driving control unit, judgment unit, clutch failure detection unit) 36. Notification unit 43. Vehicle speed sensor (parameter acquisition unit)

Claims

1. A vehicle driving control device comprising: an engine that drives the vehicle's drive wheels via a first power transmission path; a motor that drives the vehicle's drive wheels via a second power transmission path different from the first power transmission path; an engine clutch provided in the first power transmission path that can disconnect and reconnect power transmission between the engine and the drive shaft of the vehicle's drive wheels; a motor clutch provided in the second power transmission path that can disconnect and reconnect power transmission between the motor and the drive shaft; and a parameter acquisition unit that acquires parameters relating to the vehicle's driving state, wherein the vehicle driving control device controls the operation of the engine clutch, the motor clutch, the engine and the motor based on the parameters, the device comprising: a clutch failure detection unit that detects a failure of the motor clutch; and a driving control unit that, when a failure of the motor clutch is detected while the engine clutch is engaged, executes an engine driving continuation process that outputs the engine's driving force to the drive shaft regardless of the parameters.

2. The driving control device according to claim 1, characterized in that the driving control unit prohibits disengaging the motor clutch when a malfunction of the motor clutch is detected while the motor clutch is engaged, and executes the engine driving continuation process when a malfunction of the motor clutch is detected while the motor clutch is disengaged.

3. A driving control device according to claim 1 or 2, comprising a determination unit for determining whether or not the engine clutch is engaged, wherein the driving control unit stops the vehicle from driving if a malfunction of the motor clutch is detected and it is determined that the engine clutch is not engaged.

4. A driving control device according to claim 1 or 2, which is applied to a vehicle, wherein the parameter acquisition unit acquires the vehicle's driving speed as the parameter, and the driving control unit releases the engine clutch when the driving speed falls below the engine's lower limit speed, which corresponds to the engine's lower limit rotational speed, during the execution of the engine driving continuation process.

5. A driving control device according to claim 1 or 2, comprising a notification unit that notifies the motor clutch of a failure when the clutch failure detection unit detects a failure of the motor clutch.

6. The driving control device according to claim 1 or 2, characterized in that when a failure of the engine clutch is detected while the motor clutch is engaged, the driving force of the motor is transmitted to the drive shaft to drive the vehicle, regardless of the acquired parameters.

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