Travel drive control device for vehicle

Abstract

Provided is a travel drive control device 1 for a vehicle, which has an engine 2 that drives travel drive wheels of the vehicle via a first power transmission path 11, a motor 4 that drives the travel drive wheels via a second power transmission path 12 different from the first power transmission path 11, an engine clutch 7a that is capable of connecting and disconnecting the first power transmission path 11, and a motor clutch 7b that is capable of connecting the second power transmission path 12, and which controls the operations of the engine clutch 7a, the motor clutch 7b, the engine 2, and the motor 4 on the basis of a parameter such as a vehicle speed, wherein the travel drive control device 1 comprises a hybrid control unit 30 that, when a failure of the engine clutch 7a has been detected in a parallel mode, maintains engagement of the motor clutch 7b regardless of a change in the parameter and outputs a drive force of the motor 4 to a drive shaft 8 of the travel drive wheels of the vehicle.

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 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 the driving of the motor while driving the vehicle by the engine.

[0005] The engine clutch and the motor clutch 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 engine clutch fails during travel with the motor clutch released, it may become difficult to perform emergency evacuation travel.

[0008] This disclosure has been made in view of the above issues, and its purpose is to provide a vehicle drive control device that enables appropriate evasive driving in the event of engine clutch failure in a hybrid vehicle equipped with an engine clutch and a motor 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, 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, and further comprises: a clutch failure detection unit that detects a failure of the engine clutch; and a driving control unit that, when a failure of the engine clutch is detected while the engine clutch is engaged, executes a motor driving process that outputs the driving force of the motor to the drive shaft regardless of the parameters.

[0010] The vehicle drive control device of the present invention allows the vehicle to move using the motor's driving force regardless of the parameters if a failure of the engine clutch is detected while the engine clutch is engaged. This makes it possible to move the vehicle to a safer position regardless of changes in parameters when the engine clutch fails, 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 engine 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 2 and a motor 4 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, a vehicle equipped with the driving control device 1 of this embodiment can drive 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. In addition, the third power transmission path 13, which is the power transmission path between the engine 2 and the motor generator 9, is always connected.

[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 engine clutch 7a and the motor clutch 7b. 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. The hybrid control unit 30 is composed of 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 that controls the engine clutch 7a and motor clutch 7b as described above. The transmission control unit 25 is composed of 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.

[0026] 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] The hybrid control unit 30 then calculates the vehicle's required output and driving torque necessary for driving the vehicle, based on the various detection quantities and operating information from the accelerator opening sensor 40 and other sensors. The hybrid control unit 30 transmits control signals to the engine control unit 37, motor 4, motor generator 9, transmission control unit 25, etc., to switch between driving modes (EV mode: electric vehicle mode, series mode, and parallel mode), control the output of the engine 2 and motor 4, and control 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, causing the engine 2 to operate the motor generator 9. The hybrid control unit 30 then drives the motor 4 using the power generated by the motor generator 9 and the power supplied from the drive battery to propel 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 uses the engine 2 to operate the motor generator 9, and drives the motor 4 with the generated electricity and the electricity supplied from the drive battery to propel the vehicle.

[0031] The hybrid control unit 30 sets the vehicle's 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 vehicle's 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.

[0033] Furthermore, in parallel mode, if the requested output becomes, for example, 0 or less, the hybrid control unit 30 controls the motor clutch actuator 22 to release the motor clutch 7b. This allows the hybrid control unit 30 to avoid forcibly driving 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 (e.g., when the vehicle speed V0 is greater than 0 [km / h]).

[0038] First, 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] Next, the hybrid control unit 30 determines whether or not the motor clutch 7b is malfunctioning (step S20). Specifically, the hybrid control unit 30 compares the operation control signal of the motor clutch actuator 22 with the detected value of the motor clutch stroke sensor 46 to determine whether or not the motor clutch 7b is malfunctioning.

[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] If the hybrid control unit 30 determines in step S10 that the value of the failsafe flag F1 is 1, or if it executes the process in step S40, it determines whether or not 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 an open state, it acquires the currently set driving mode based on the vehicle speed V and the requested output, etc. (step S60).

[0044] Then, as shown in Figure 3, the hybrid control unit 30 determines whether the current driving mode is parallel mode or not (step S70).

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

[0046] Next, the hybrid control unit 30 determines whether or not the vehicle speed V is less than the minimum speed at which the vehicle can travel in the parallel mode (parallel minimum speed Vp) (step S90). The parallel minimum speed Vp is the vehicle speed corresponding to the lower limit rotational 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 disengage 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] When the hybrid control unit 30 determines in step S70 that the driving mode of the vehicle is not the parallel mode (determines that the driving mode of the vehicle is the series mode or the EV mode), it stops the running of the vehicle (step S130). Specifically, 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] Further, as shown in FIG. 2, when the hybrid control unit 30 determines in step S50 that the motor clutch is not in the released state (is in the engaged state), it prohibits the release of the motor clutch 7b and maintains the engaged state (step S140).

[0050] Furthermore, when 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 of the vehicle to the driving mode set based on the vehicle speed V, required output, etc.

[0051] Then, if the hybrid control unit 30 determines in step S90 that the speed V is equal to or greater than the minimum parallel speed Vp, or if it executes any of the processes in steps S100, S130, S140, and S150, it 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), 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] Furthermore, the hybrid control unit 30 determines that the motor clutch 7b is open (step S50), and if it 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] Furthermore, when the hybrid control unit 30 determines whether the motor clutch 7b is open, if the motor clutch 7b is open (YES in step S50), or if the mode is not parallel mode (series mode or EV mode) (NO in step S70), it stops the vehicle (step S130). If the driving mode is parallel mode, the engine clutch 7a is released after the vehicle speed V has decreased to the minimum parallel speed Vp, so that the engine 2 can drive the vehicle at a low speed until the vehicle speed V has decreased to the minimum parallel speed Vp.

[0055] 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.

[0056] <Driving control in case of engine clutch failure> The hybrid control unit 30 also performs engine clutch failure control, which controls the vehicle to be able to move in an escape position when the engine clutch 7a fails. Note that the engine clutch failure control may also be performed by the transmission control unit 25.

[0057] Figures 4 and 5 are flowcharts showing an example of a control procedure for engine clutch failure control.

[0058] Engine clutch failure control 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).

[0059] 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.

[0060] When the hybrid control unit 30 determines that the value of the failsafe flag F2 is 0, it determines whether or not the engine clutch 7a is malfunctioning (step S220). Specifically, the hybrid control unit 30 compares the operation control signal of the engine clutch actuator 21 with the detected value of the engine clutch stroke sensor 45 to determine whether or not the engine clutch 7a is malfunctioning.

[0061] 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).

[0062] The hybrid control unit 30 controls the notification unit 36 ​​to start notifying the driver that the engine clutch 7a is malfunctioning (step S240).

[0063] If the hybrid control unit 30 determines in step S210 that the value of the failsafe flag F2 is 1, or if it executes the process in step S240, it acquires the current driving mode set based on the vehicle speed V and the requested output, and determines whether or not the driving mode is parallel mode (step S250).

[0064] When the hybrid control unit 30 determines that the driving mode is parallel mode, it controls the engine clutch actuator 21 to release the engine clutch 7a and terminate the parallel mode (step S260). As a result, the vehicle's driving mode will transition to a driving mode other than parallel mode (series mode or EV mode) based on the vehicle speed, requested output, etc., as described above.

[0065] 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.

[0066] Furthermore, if the hybrid control unit 30 determines in step S250 that the vehicle's driving mode is series mode or EV mode, it 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).

[0067] Then, when the hybrid control unit 30 determines that the engine clutch 7a is not in the open state, it determines that the engine clutch 7a is stuck and terminates the series mode, as shown in Figure 5, 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).

[0068] Next, the hybrid control unit 30 obtains the engine torque Te from the engine control unit 37 (step S300).

[0069] Next, the hybrid control unit 30 obtains the current vehicle speed V from the vehicle speed sensor 43 (step S310).

[0070] The hybrid control unit 30 then determines whether the engine torque Te is less than or equal to the lower limit torque (in this embodiment, torque 0 [Nm]) (step S320).

[0071] When 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, speed 20 [km / h]) (step S330).

[0072] When the hybrid control unit 30 determines that the vehicle speed V is less than or equal to the maximum vehicle speed Vf in case of failure, it performs driving with the motor 4 up to the maximum vehicle speed Vf in case of failure (for example, speed of 20 [km / h]) (step S340).

[0073] If the hybrid control unit 30 determines in step S320 that the engine torque Te is greater than torque 0 [Nm], it controls the amount of power generated by the motor generator 9 to offset the engine torque Te (step S350). The hybrid control unit 30 controls the deceleration of the vehicle by controlling the motor generator 9 in this way.

[0074] Then, the hybrid control unit 30 controls the motor torque to 0 [Nm] and decelerates the vehicle (step S360).

[0075] Furthermore, as shown in Figure 4, if the hybrid control unit 30 determines in step S280 that the engine clutch 7a is not in the disengaged state (i.e., it is in the engaged state), it prohibits the parallel mode (step S370). In other words, even if conditions for selecting the parallel mode are met due to changes in vehicle speed V or requested output, the hybrid control unit 30 does not switch to the parallel mode and maintains the series mode or EV mode.

[0076] Furthermore, 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). That is, the hybrid control unit 30 updates the vehicle's driving mode to a driving mode set based on the vehicle speed V, requested output, etc.

[0077] Then, when the hybrid control unit 30 has executed any of the processes in steps S270, S340, S360, S360, and S380, it returns this routine.

[0078] 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).

[0079] Furthermore, the hybrid control unit 30 determines that the engine clutch 7a is faulty (YES in step S220), and if it is in parallel mode (YES in step S250), it terminates the parallel mode (step S260).

[0080] 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.

[0081] 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), and terminates series mode, reducing the engine torque Te to friction torque Tf (step S290).

[0082] Furthermore, if the engine torque Te becomes 0 [Nm] or less 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).

[0083] Furthermore, if the engine torque Te exceeds 0 [Nm], 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).

[0084] Furthermore, the hybrid control unit 30 also decelerates the vehicle by setting the motor torque Tm to 0 [Nm] if the engine torque Te is 0 [Nm] or less (YES in step S320) and the vehicle speed V exceeds the upper limit vehicle speed Vf in case of failure (NO in step S330) (step S360).

[0085] 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 until the vehicle has come to a complete stop.

[0086] <Operation of driving control when engine clutch fails> Figure 6 is an explanatory diagram showing the control content of the engine clutch failure control, and shows the driving control content when the engine clutch 7a is functioning normally and when it fails during parallel driving.

[0087] As shown in Figure 6, when the vehicle is driving in parallel mode and the engine clutch 7a is functioning normally, the engine clutch 7a disengages and the vehicle switches to series mode or EV mode when it is determined to be in series mode or EV mode based on changes in parameters related to the driving state, such as vehicle speed V and required driving force.

[0088] If the engine clutch 7a is found to be faulty while the vehicle is running in parallel mode, the parallel mode or series mode will be terminated regardless of the parameters related to the driving state, and the motor clutch 7b will be kept engaged. This allows the vehicle to be driven by the motor 4 while reducing the vehicle speed, enabling it to move to a safer position. In addition, by limiting the driving force of the motor 4 at this time, smooth deceleration is possible.

[0089] As described above, in this embodiment, if a malfunction of the engine clutch 7a is detected while driving, the parallel mode is terminated if the vehicle is in parallel mode. Furthermore, if a malfunction is detected while the engine clutch 7a is engaged, switching to parallel mode is prohibited. In other words, if a malfunction of the engine clutch 7a is detected while the vehicle is engaged and in parallel mode based on parameters such as vehicle speed V and required driving force, the vehicle is set to a driving mode in which the motor clutch 7b is not released, regardless of subsequent changes in parameters.

[0090] As a result, even if the parameters related to the vehicle's driving state become such that the motor clutch 7b should be released, the motor clutch 7b is kept engaged, and the motor driving continuation process is executed, transmitting the driving force of the motor 4 to the drive shaft 8. Therefore, it becomes possible to move the vehicle to a safe location, thereby enhancing safety.

[0091] Furthermore, if the hybrid control unit 30 determines that the engine clutch 7a is disengaged and malfunctioning, and the engine torque Te falls below the lower limit torque and the vehicle speed V is below the lower limit speed, it performs motor driving continuation processing using motor torque to suppress the upper limit speed. Also, if the engine torque Te exceeds the lower limit torque or the vehicle speed V exceeds the lower limit speed, the hybrid control unit 30 sets the motor torque to 0 [Nm].

[0092] This prevents engine 2 from rotating due to motor drive during the motor-driven continuous operation process, thereby suppressing engine stoppage and damage to engine 2, and making it easier for the driver to safely take evasive action.

[0093] Furthermore, by suppressing the upper speed limit and continuing the motor-driven operation process as described above, damage to the engine 2 due to forced rotation at high speeds can be sufficiently suppressed.

[0094] The hybrid control unit 30 enables power transmission between the engine 2 and the motor generator 9 via the third power transmission path 13. If the engine clutch 7a is found to be malfunctioning in the open state as described above, and the engine torque exceeds the lower limit torque, the motor generator 9 regenerates power to absorb the engine torque. This allows the engine torque to be reduced rapidly.

[0095] Furthermore, if the engine clutch 7a is found to be malfunctioning in the disengaged state as described above, and the vehicle speed V exceeds the lower limit speed, the motor torque can be set to the lower limit motor torque (torque 0 [Nm], the motor torque corresponding to the lower limit torque of engine 2), thereby allowing for a rapid reduction in speed during evacuation. Alternatively, the motor torque may be reduced towards the lower limit motor torque (torque 0 [Nm]) at this time. This allows for a smooth deceleration of the vehicle during evacuation.

[0096] Furthermore, even if the engine clutch is determined to be malfunctioning while engaged, if the engine torque Te exceeds the lower limit torque, the motor generator 9 may be used to regenerate power and absorb the engine torque Te. This allows the motor generator 9 to regenerate power and absorb the engine torque Te, while simultaneously rapidly reducing the vehicle speed.

[0097] Furthermore, if a malfunction of the engine clutch 7a is detected, the hybrid control unit 30 notifies the driver of the malfunction via the notification unit 36. This allows the driver to easily recognize the malfunction of the engine clutch 7a and take evasive action.

[0098] 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 is switchable between two gear ratios, high gear and low gear, but the clutch may be switchable between three or more gear ratios, or it may be a clutch that only switches between connecting and disconnecting without switching the gear ratio.

[0099] 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.

[0100] 1. Driving control device 2. Engine 4. Motor 7b. Motor clutch 7a. Engine clutch 8. Drive shaft 9. Motor generator 11. First power transmission path 12. Second power transmission path 13. Third 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, comprising: a clutch failure detection unit that detects a failure of the engine clutch; and a driving control unit that, when a failure of the engine clutch is detected while the engine clutch is engaged, executes a motor driving process that engages the motor clutch regardless of the parameters and outputs the driving force of the motor to the drive shaft.

2. A driving control device according to claim 1, which is applied to a vehicle, wherein the parameter acquisition unit acquires the vehicle's driving speed and the engine's output torque as parameters, and the driving control unit executes the motor driving process when the engine's output torque falls below a predetermined lower limit torque and the vehicle speed falls below a predetermined lower limit speed.

3. The driving control device according to claim 2, characterized in that the driving control unit sets the output torque of the motor to a lower limit motor torque, which is the output torque of the motor that allows the vehicle to travel at the lower limit speed, in the motor driving process.

4. A driving control device according to claim 2 or 3, applicable to a vehicle having a battery and a motor generator, and a third power transmission path for transmitting power between the motor generator, the drive shaft, and the engine, wherein the driving control unit cancels out the output torque of the engine by regenerating power using the motor generator when the output torque of the engine exceeds a predetermined lower limit torque.

5. The driving control device according to claim 2 or 3, characterized in that the driving control unit controls the output torque of the motor to the lower limit torque or a torque that decreases toward the lower limit torque when the driving speed of the vehicle exceeds the lower limit speed.

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

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