Vehicle control device

Abstract

To provide a control device of a vehicle that can suppress a clutch from being damaged and lengthen a postponement time until a state is transferred to a travelling restriction state, even when a failure by which the clutch may be damaged occurs.SOLUTION: When a failure occurs in an actuator or in a TCM (YES in a step S1 or YES in a step S2), an ECM sets a continuous travelable time during which a vehicle can continue to travel without damaging a clutch, on the basis of a damage risk that damage of the clutch is caused (a step S7 and a step S8). After the continuous travelable time elapses (YES in a step 9), the ECM switches a state to a predetermined travelling restriction state where a restriction of idle torque is executed so as to reduce loads acting on the clutch (a step S10). The travelling restriction state is a travelling state where an engine rotation speed of an engine is restricted to the vicinity of an idling rotation speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Patent Document 1 discloses a vehicle control device in which an engine connecting / disconnecting clutch is biased toward the engaging side so as to transmit a predetermined transmission torque smaller than the maximum transmission torque when control for connecting / disconnecting the engine and the electric motor is not performed, and in which, if an abnormality occurs in the connecting / disconnecting control of the engine connecting / disconnecting clutch, an engine torque command value is determined based on a user-requested engine torque so that the differential rotation of the clutch falls within an allowable differential rotation.As a result, the vehicle control device described in Patent Document 1 can prevent the clutch from seizing in the event of a clutch failure and enable evacuation driving using the determined engine torque command value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-54633 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional vehicle control device described in Patent Document 1, a disc spring is configured to bias the clutch toward the engagement side to achieve a predetermined torque transmission state when the clutch is not engaged or when it fails. However, the device does not consider a clutch system that maintains its current engaged state in the event of a clutch failure. In other words, in the case of a normally open clutch system that completely releases the clutch when the clutch system fails, or a normally closed clutch system that completely engages (connects) the clutch when the clutch system fails, a countermeasure can be taken based on the predicted state. However, the device does not consider a normally stop clutch system, which maintains its failed state in the event of a clutch failure. For this reason, the vehicle control device described in Patent Document 1 may not be able to prevent clutch seizure and ensure sufficient evacuation driving when the vehicle is equipped with a normally stop clutch system, because the engagement state of the clutch is not constant in the event of a clutch failure and the likelihood of differential rotation occurring is also variable.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a vehicle control device that can suppress damage to the clutch even in the event of a failure that could damage the clutch, and that can extend the grace period before transitioning to a restricted driving state. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a control device for a vehicle that includes an engine, a transmission that changes the rotation of the engine at a speed ratio corresponding to the gear position and outputs the rotation to drive wheels, a clutch that can be switched to an engaged state in which power is transmitted between the engine and the transmission or to an open state in which the power is not transmitted, an actuator that performs switching operations for the clutch, and a clutch control unit that controls the actuator, wherein, in the event of a failure of the actuator or the clutch control unit, the control device is characterized by including a driving state control unit that sets a continuous driving time during which the clutch can continue to drive without being damaged based on the risk of damage that would cause damage to the clutch, and switches the vehicle to a predetermined restricted driving state in which the load acting on the clutch is small after the continuous driving time has elapsed. [Effects of the Invention]

[0007] According to the present invention, a vehicle control device can be provided that can suppress damage to the clutch even in the event of a failure that could damage the clutch, and can extend the grace period before transitioning to a restricted driving state. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the flow of a fail-safe operation when a clutch fails, performed by a vehicle control device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a tendency of setting the remaining driving time that is referred to when a fail-safe operation is performed in a vehicle control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A vehicle control device according to one embodiment of the present invention is a vehicle control device including an engine, a transmission that changes the engine rotation speed at a gear ratio corresponding to a gear position and outputs the engine rotation to drive wheels, a clutch that can be switched between an engaged state that transmits power between the engine and the transmission and an open state that does not transmit power, an actuator that switches the clutch, and a clutch control unit that controls the actuator, and is characterized in that, in the event of a failure of the actuator or the clutch control unit, the vehicle control device further includes a driving state control unit that sets a continuous driving time during which driving can continue without damaging the clutch based on a damage risk that would cause damage to the clutch, and switches the vehicle to a predetermined restricted driving state in which the load acting on the clutch is small after the continuous driving time has elapsed. As a result, even in the event of a failure that could damage the clutch, the vehicle control device according to one embodiment of the present invention can suppress damage to the clutch and extend the grace period before transitioning to the restricted driving state. [Example]

[0010] A vehicle equipped with a control device according to an embodiment of the present invention will be described below with reference to the drawings.

[0011] As shown in FIG. 1, a vehicle 1 according to this embodiment includes an engine (referred to as ENG in the figure) 2, a motor generator (referred to as MG in the figure) 3, a transmission (referred to as T / M in the figure) 4, a differential 5, drive wheels 6, a clutch 7, an ECM (Engine Control Module) 10 that controls the engine 2, and a TCM (Transmission Control Module) 12 that controls the transmission 4 and the clutch 7.

[0012] The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured so that each cylinder undergoes a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0013] An ISG (Integrated Starter Generator) 20 is connected to the engine 2. The ISG 20 is connected to a crankshaft 2A of the engine 2 via a power transmission member 21 such as a belt. The ISG 20 functions as an electric motor that rotates when supplied with electric power, thereby driving the engine 2 to rotate, and also functions as a generator that converts the rotational force input from the crankshaft 2A into electric power.

[0014] The motor generator 3 functions as an electric motor driven by power supplied from a battery 31 (referred to as Batt in the figure) via an inverter 30 (referred to as INV in the figure), and as a generator that generates electricity regeneratively using the reverse driving force input from the differential 5.

[0015] The motor generator 3 is provided in a power transmission path between the transmission 4 and the left and right drive wheels 6, and is connected to be able to transmit power to the left and right drive wheels 6. In detail, the motor generator 3 is connected to be able to exchange driving force with the power transmission path between the transmission 4 and the differential 5, which is also a power transmission path between the output shaft 4B of the transmission 4 and a drive shaft 3A that transmits driving force to the differential 5.

[0016] Under the control of the ECM 10, the inverter 30 converts DC power supplied from the battery 31 into three-phase AC power and supplies it to the motor generator 3, and also converts the three-phase AC power generated by the motor generator 3 into DC power to charge the battery 31. The battery 31 is formed by a secondary battery such as a lithium-ion battery.

[0017] The transmission 4 changes the rotation output from the engine 2 at a gear ratio corresponding to one of a plurality of gear positions and outputs the rotation to an output shaft 4B. The transmission 4 has a parallel shaft gear type transmission mechanism generally used in manual transmissions. The output shaft 4B of the transmission 4 is connected to left and right drive wheels 6 via a differential 5 and left and right drive shafts 8. The motor generator 3 is connected to the output shaft 4B of the transmission 4, and is connected to the differential 5 via a drive shaft 3A. In other words, the motor generator 3 and the transmission 4 are each connected to the drive wheels 6 so as to be able to transmit drive power independently, and the drive power of the engine 2, which has been changed in speed by the transmission 4, and the drive power of the motor generator 3 are transmitted to the drive wheels 6.

[0018] The gears that can be established in the transmission 4 include, for example, forward driving gears ranging from a low 1st gear to a high 5th gear, and a reverse gear. The number of driving gears varies depending on the specifications of the vehicle 1, and is not limited to the above-mentioned 1st gear to 5th gear.

[0019] The gear positions in the transmission 4 are automatically switched under the control of the TCM 12 in accordance with the operating position (shift range) of the shift selector 40, the accelerator opening, etc. The operating position of the shift selector 40 is detected by a shift position sensor 41. The shift position sensor 41 is connected to the TCM 12 and transmits the detection results to the TCM 12. The accelerator opening is detected by an accelerator opening sensor 91, which detects the amount of depression of an accelerator pedal 90. The accelerator opening sensor 91 is connected to the ECM 10 and transmits the detection results to the ECM 10.

[0020] The transmission 4 is provided with a gear position sensor 42. The gear position sensor 42 is connected to the TCM 12. The gear position sensor 42 detects the gear position established in the transmission 4 and outputs a detection signal to the TCM 12.

[0021] The vehicle 1 is equipped with a clutch 7. The clutch 7 is provided in a power transmission path between the engine 2 and the transmission 4. For example, a dry single-plate friction clutch can be used as the clutch 7. The engine 2 and the transmission 4 are connected via the clutch 7. The clutch 7 can be switched between an engaged state in which power is transmitted between the engine 2 and the transmission 4, a disengaged state in which power is not transmitted, and a half-engaged state in which torque is transmitted with a rotational difference.

[0022] The vehicle 1 is equipped with an accelerator pedal 90 that is operated by the driver. The amount of depression of the accelerator pedal 90 is detected by an accelerator position sensor 91. The accelerator position sensor 91 is connected to the ECM 10, detects the amount of depression of the accelerator pedal 90 as an accelerator position, and transmits a signal corresponding to the accelerator position to the ECM 10.

[0023] The vehicle 1 is equipped with a brake pedal 92 that is operated by the driver. The amount of depression of the brake pedal 92 is detected by a brake pedal sensor 93. The brake pedal sensor 93 is connected to the ECM 10 and transmits a signal corresponding to the amount of depression of the brake pedal 92 to the ECM 10.

[0024] The vehicle 1 is equipped with an actuator 70. The actuator 70 performs a shifting operation of the clutch 7. The actuator 70 also performs a shifting operation of the gear stage of the transmission 4. The actuator 70 is connected to the TCM 12 and is controlled by the TCM 12. In this way, the transmission 4 and the clutch 7 are configured as an AMT (Automated Manual Transmission) that automates the shifting operation and clutch operation based on the structure of a manual transmission.

[0025] The actuator 70 is configured as an electric actuator having a clutch switching motor and a gear stage switching motor (not shown). The actuator 70 has a normally stop type structure.

[0026] In the event of a failure of the actuator 70 or the TCM 12, the normally-stop actuator 70 has the characteristic that, if a failure occurs and power is cut off, the clutch 7 maintains the engaged state at the time of the failure. For example, if a failure occurs and power is cut off when the clutch 7 is engaged, the clutch 7 maintains the engaged state. If a failure occurs and power is cut off when the clutch 7 is disengaged, the clutch 7 maintains the disengaged state. Furthermore, if a failure occurs and power is cut off when the clutch 7 is partially engaged, the clutch 7 maintains the partially engaged state.

[0027] In a normally closed hydraulic actuator, which has been widely used in the past, hydraulic pressure is released in the event of a failure in which power is interrupted. A clutch equipped with this hydraulic actuator is normally closed because the restoring force of a clutch spring (such as a diaphragm spring) returns the clutch to its engaged state when hydraulic pressure is released. Here, a failure of the actuator 70 may be, for example, a state in which the actuator 70 cannot operate due to a break in the internal wiring of the actuator 70. Furthermore, a failure of the TCM 12 may be, for example, a state in which it cannot output a control command to the actuator 70.

[0028] The ECM10 and TCM12 are composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports, and output ports.

[0029] The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECM 10. That is, the CPU executes the program stored in the ROM using the RAM as a work area, causing the computer unit to function as the ECM 10 and TCM 12 in this embodiment.

[0030] A vehicle speed sensor 11 is connected to the ECM 10. The vehicle speed sensor 11 detects the vehicle speed of the vehicle 1 and transmits the detection result to the ECM 10.

[0031] The ECM 10 switches the driving mode of the vehicle 1. In this embodiment, an EV mode and an HEV mode are set as the driving modes.

[0032] The EV mode is a driving mode in which the clutch 7 is disengaged and the vehicle 1 is driven by the power of the motor generator 3. The HEV mode is a driving mode in which the clutch 7 is engaged and the vehicle 1 is driven by the power of the engine 2, or the engine 2 and the motor generator 3.

[0033] The ECM 10 switches between the EV mode and the HEV mode based on, for example, the accelerator opening and the engine rotation speed.

[0034] For example, when the driver's requested torque determined by the accelerator opening exceeds the HEV transition threshold while the vehicle is traveling in the EV mode, the ECM 10 restarts the engine 2 and transitions to the HEV mode.

[0035] For example, when the driver's requested torque, which is determined by the accelerator opening and the engine rotation speed, falls below the EV transition threshold while the vehicle is running in the HEV mode, the ECM 10 stops the engine 2 and transitions to the EV mode.

[0036] The TCM 12 is connected to a shift position sensor 41, a gear position sensor 42, and the ECM 10. The TCM 12 controls the clutch 7 and the transmission 4 by driving an actuator 70 in response to input signals from the shift position sensor 41 and the gear position sensor 42 and a control command from the ECM 10.

[0037] Here, the states of the clutch 7 when the actuator 70 or TCM 12 fails include a state in which the clutch 7 is maintained in a semi-engaged state, a state in which the clutch 7 is maintained in an engaged state, and a state in which the clutch 7 is maintained in a released state.

[0038] When the clutch 7 is maintained in a semi-engaged state, if a large differential rotation occurs in the clutch 7 and the engagement surface of the clutch 7 becomes hot due to frictional heat, the clutch 7 may seize and be damaged. Clutch seizure occurs when the engagement surface of the clutch 7 and the flywheel in contact with this engagement surface become stuck at an abnormally high temperature. Because the clutch 7 is stuck, it becomes impossible to release the clutch 7. In addition, if a large differential rotation occurs in the clutch 7 and the engagement surface of the clutch 7 becomes hot due to frictional heat, the characteristics of the engagement surface change, the friction coefficient decreases, and problems such as an inability to properly transmit driving force may occur.

[0039] When the clutch 7 is maintained in an engaged state, frictional heat due to differential rotation of the clutch 7 is unlikely to be generated, and there is little risk of the clutch 7 seizing. When the clutch 7 is maintained in a disengaged state, frictional heat is not generated in the clutch 7, and there is no risk of the clutch 7 seizing.

[0040] As such, the engagement state of the clutch 7 during a breakdown is not constant. Furthermore, the risk of damage to the clutch 7 varies depending on the state of differential rotation (slippage) of the clutch 7, etc. Damage such as seizure of the clutch 7 can be avoided to some extent by reducing the engine torque to idle torque to suppress the differential rotation of the clutch 7. However, if the engine torque is reduced immediately upon the occurrence of a breakdown, it may become difficult to evacuate the vehicle to a repair center, etc.

[0041] Therefore, it is preferable that seizure of the clutch 7 can be suppressed, and that the time during which the vehicle can be driven without seizure of the clutch 7 can be appropriately secured.

[0042] Therefore, in this embodiment, if a failure occurs in the actuator 70 or the TCM 12, the ECM 10 sets a continuous driving time during which driving can continue without damaging the clutch 7, based on the risk of damage to the clutch 7. After the continuous driving time has elapsed, the ECM 10 switches the vehicle to a predetermined limited driving state in which the load acting on the clutch 7 is small. If a failure occurs in the actuator 70 or the TCM 12, the ECM 10 may notify the driver of this.

[0043] The limited running state is a running state in which the engine rotation speed of the engine 2 is limited to a value close to the idling rotation speed. More specifically, the limited running state is a running state in which the engine torque is limited to an idle torque generated close to the idling rotation speed, and this idle torque acts on the clutch 7.

[0044] The remaining continuous driving time is determined in advance through experiments or the like and stored in the ROM of the ECM 10. If a failure occurs in the actuator 70 or the TCM 12, the ECM 10 sets the remaining continuous driving time based on the risk of damage from the stored remaining continuous driving time. Note that since this remaining continuous driving time is a variable that changes depending on the clutch transmission torque, engine torque, vehicle speed, and other conditions that correspond to the engagement state of the clutch 7 at the time of the failure, the ECM 10 reviews the remaining continuous driving time while the vehicle is running after the failure occurs, and corrects and updates the currently set remaining continuous driving time.

[0045] The risk of damage to the clutch 7 depends on the magnitude relationship between the engine torque and the clutch transmission torque, the magnitude relationship between the vehicle speed and a predetermined vehicle speed, and the like.

[0046] For example, if the engine torque is greater than the clutch transmission torque at the time of failure, the differential rotation of the clutch 7 will be large, increasing the risk of damage, and therefore the possible continuous driving time will be set short. Conversely, if the engine torque is equal to or less than the clutch transmission torque at the time of failure, the differential rotation of the clutch 7 will be small, decreasing the risk of damage, and therefore the possible continuous driving time will be set long.

[0047] Furthermore, in the case of a breakdown during high-speed driving, the vehicle speed will be greater than the specified vehicle speed, and the engine torque will be relatively large, which will increase the differential rotation of the clutch 7 and pose a significant risk of damage, so the continuous driving time is set to a short time.

[0048] Conversely, when the vehicle speed is equal to or lower than the predetermined vehicle speed, the engine torque is relatively small, which reduces the differential rotation of the clutch 7 and reduces the risk of damage, so the continuous driving time is set long. In other words, the potential risk of damage can be evaluated only from an estimation of the engine torque based on the vehicle speed, without comparing the engine torque with the clutch transmission torque.

[0049] Even if a failure occurs during high-speed driving, evacuation driving is possible without being limited by idle torque until the short, set continuous driving time has elapsed. After the continuous driving time has elapsed, the idle torque is limited while the transmission gear is maintained in a high-speed driving gear (for example, fifth gear). However, because the vehicle is driven at idle speed in the high-speed driving gear, engine stall may occur due to insufficient torque.

[0050] If the actuator 70 fails, the ECM 10 sets the possible continuous driving time based on the risk of damage corresponding to the engine torque of the engine 2. More specifically, even if the actuator 70 fails, the TCM 12 can obtain the clutch transmission torque at that time, and therefore sets the possible continuous driving time according to the result of comparing the engine torque and the clutch transmission torque.

[0051] If the TCM 12 fails, the ECM 10 sets the remaining driving time based on the damage risk corresponding to the vehicle speed. Specifically, if the TCM 12 fails, the TCM 12 cannot obtain the clutch transmission torque at that time, and the comparison result between the engine torque and the clutch transmission torque cannot be used. However, if the vehicle speed is high, the engine torque is also high, making it more likely that differential rotation of the clutch 7 will occur. Therefore, the ECM 10 sets the remaining driving time based on the damage risk corresponding to the engine torque corresponding to the vehicle speed. Note that the remaining driving time set as described above is a variable that changes depending on the clutch transmission torque, engine torque, vehicle speed, and other conditions. Therefore, the ECM 10 reviews the remaining driving time at predetermined intervals during driving after the failure occurs, and the set value is corrected and updated.

[0052] Next, a flow of the fail-safe operation by the ECM 10 according to this embodiment when a failure occurs in the clutch 7 will be described with reference to Fig. 2. The process shown in Fig. 2 is repeatedly executed at predetermined time intervals while the vehicle 1 is running.

[0053] 2, the ECM 10 determines whether or not the TCM 12 has failed (step S1). Here, the ECM 10 determines that the TCM 12 has failed when communication with the TCM 12 is interrupted or the like.

[0054] If the ECM 10 determines in step S1 that the TCM 12 is not malfunctioning, it then determines whether the clutch system is malfunctioning (step S2). Here, the ECM 10 determines that the clutch system is malfunctioning when it detects an abnormality in the clutch switching motor of the actuator 70.

[0055] If the ECM 10 determines in step S2 that the clutch system is not malfunctioning, it ends this operation. If the ECM 10 determines in step S2 that the clutch system is malfunctioning, it calculates the engine torque and the clutch transmission torque (step S3).

[0056] Next, the ECM 10 determines whether the engine torque is greater than the clutch transmission torque (step S4).

[0057] On the other hand, if the ECM 10 determines in step S1 that the TCM 12 has failed, it calculates the vehicle speed (step S5).

[0058] Next, the ECM 10 determines whether the vehicle speed is greater than a predetermined vehicle speed (step S6).

[0059] If the ECM 10 determines in step S4 that the engine torque is greater than the clutch transmission torque, or if the ECM 10 determines in step S6 that the vehicle speed is greater than the predetermined vehicle speed, it sets the allowable continuous driving time to a short time (step S7).

[0060] If the ECM 10 determines in step S4 that the engine torque is equal to or less than the clutch transmission torque, or if the ECM 10 determines in step S6 that the vehicle speed is equal to or less than the predetermined vehicle speed, it sets the allowable continuous driving time to a long time (step S8).

[0061] After executing step S7 or step S8, the ECM 10 repeatedly determines whether the allowable continuous driving time has elapsed (step S9). This step S9 is executed as a timer until the allowable continuous driving time has elapsed.

[0062] If the ECM 10 determines in step S9 that the continuous travel time has elapsed (that is, if the continuous travel time has elapsed), it implements the idle torque restriction (step S10) and ends the current operation.

[0063] The idling torque limitation in step S10 is a process of limiting the engine rotation speed to near the idling rotation speed so that the engine torque is limited to the idling torque, thereby reducing the load acting on the clutch 7. That is, in step S10, the ECM 10 switches to the limited running state.

[0064] Next, the method for setting the remaining continuous driving time will be further described with reference to FIG.

[0065] The remaining continuous driving time setting table shown in FIG. 3 defines the relationship between the state and remaining continuous driving time for each item such as engine torque, vehicle speed, degree of clutch engagement of the clutch 7, and differential rotation.

[0066] As shown in Figure 3, when the engine torque is high, the clutch 7 is likely to slip, and it is expected that the clutch 7 will heat up and seize in a short period of time, so the remaining continuous driving time is set to be short. When the engine torque is low, the remaining continuous driving time is set to be relatively long. The engine torque can be estimated from the throttle opening, the amount of depression of the accelerator pedal, or the engine speed. The remaining continuous driving time may be determined from the engine torque at the moment of failure, or from an integrated value of the throttle opening, etc. When the vehicle speed is high, the remaining continuous driving time is set to be short, and when the vehicle speed is low, the remaining continuous driving time is set to be long.

[0067] When the degree of clutch engagement is small, the continuous driving time is set to a short time, and when the degree of clutch engagement is large or medium, the continuous driving time is set to a long time. When the differential rotation of the clutch 7 is large, the continuous driving time is set to a short time, and when the differential rotation is small, the continuous driving time is set to a long time. Here, the differential rotation is the difference between the rotation speed of the crankshaft 2A and the rotation speed of the input shaft 4A, and refers to the relative rotation speed between the input shaft and output shaft of the clutch 7.

[0068] During EV control, in which control is performed to switch to EV mode, the clutch 7 is controlled to a completely released state to prevent the engine 2 from rotating entrained, and so the completely released state is maintained even in the event of a failure of the clutch 7. For this reason, a long continuous driving time is set, and when the engine needs to run after the continuous driving time has elapsed, the idle torque is limited, thereby urging the driver to have the vehicle repaired. During EV control, there is no risk of damage to the clutch 7, so the idle torque may not be limited.

[0069] The method for setting the remaining continuous driving time is not limited to a method for setting a long or short remaining continuous driving time, but may be a method for setting a longer or shorter remaining continuous driving time. Also, a method for setting the remaining continuous driving time in multiple stages by referring to the states of multiple items such as engine torque, vehicle speed, clutch engagement degree, and differential rotation can be used.

[0070] As described above, the vehicle control device according to this embodiment includes an ECM 10 that sets the continuous driving time during which driving can continue without damaging the clutch 7 in the event of a failure of the actuator 70 or TCM 12, based on the risk of damage that may cause damage to the clutch 7, and switches to a predetermined restricted driving state in which the load acting on the clutch 7 is small after the continuous driving time has elapsed.

[0071] As a result, even if the engagement state of the clutch 7 cannot be changed due to a failure of the actuator 70 or TCM 12, the vehicle will not immediately be switched to the restricted driving state, and the vehicle can be driven according to the driver's driving operation until the continuous driving time has elapsed. Therefore, the vehicle can be driven to a repair base or the like while driving in a manner that reflects the driver's intentions.

[0072] In addition, if the driver performs driving operations in a manner that reduces the risk of damage to the clutch 7, the amount of time that the vehicle can continue to travel can be extended, and the grace period before the vehicle transitions to a restricted travel state can be extended.

[0073] Furthermore, after the continuous travel time has elapsed, the vehicle transitions to a restricted travel state in which the load acting on the clutch 7 is small, so damage to the clutch 7 can be suppressed.

[0074] As a result, even if a failure occurs that could damage the clutch 7, damage to the clutch 7 can be suppressed and the grace period before transition to the restricted traveling state can be extended.

[0075] In the vehicle control device according to this embodiment, the limited running state is a running state in which the engine rotation speed of the engine 2 is limited to a value close to the idling rotation speed.

[0076] As a result, in the limited running state, the small idle torque at the time of idling rotation of the engine 2 acts on the clutch 7, so the load acting on the clutch 7 can be reliably reduced and damage to the clutch 7 can be suppressed.

[0077] Furthermore, in the vehicle control device according to this embodiment, when the TCM 12 fails, the ECM 10 sets the allowable continuous driving time based on the damage risk according to the vehicle speed.

[0078] As a result, even in the event of a failure of the TCM 12 that makes it impossible to obtain the engagement state of the clutch 7, the possible continuous driving time can be set by estimating the engine torque and the state of the transmission 4 based on the vehicle speed. Therefore, the driver can extend the possible continuous driving time by performing driving operations to keep the vehicle speed low.

[0079] Furthermore, in the vehicle control device according to this embodiment, when the actuator 70 fails, the ECM 10 sets the allowable continuous driving time based on the damage risk according to the engine torque of the engine 2.

[0080] As a result, the possible continuous driving time is set based on the magnitude relationship between the engine torque and the transmission torque of the clutch 7 at the time of failure. Therefore, the driver can extend the possible continuous driving time by performing driving operations to reduce the engine torque.

[0081] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0082] 1 vehicle 2 engines 4-speed 7. Clutch 10 ECM (driving condition control unit) 12 TCM (Clutch control unit) 70 Actuator

Claims

1. The engine and a transmission that changes the rotation of the engine at a speed ratio corresponding to a gear position and outputs the rotation to drive wheels; a clutch that can be switched between an engaged state in which power is transmitted between the engine and the transmission and an open state in which power is not transmitted; an actuator for switching the clutch; a clutch control unit that controls the actuator, A vehicle control device characterized by comprising a driving state control unit that sets a continuous driving time during which driving can continue without damaging the clutch in the event of a failure of the actuator or the clutch control unit, based on the risk of damage that would cause damage to the clutch, and switches to a predetermined restricted driving state in which the load acting on the clutch is small after the continuous driving time has elapsed.

2. 2. The vehicle control device according to claim 1, wherein the limited running state is a running state in which the engine rotation speed of the engine is limited to a value close to an idling rotation speed.

3. 3. The vehicle control device according to claim 1, wherein the driving state control unit sets the allowable continuous driving time based on the damage risk according to the vehicle speed when the clutch control unit fails.

4. 3. The vehicle control device according to claim 1, wherein the driving state control unit sets the continuous driving time based on the damage risk corresponding to the engine torque of the engine when the actuator fails.

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