JP5776153B2 - Vehicle control apparatus and vehicle control method - Google Patents

Description

  The present invention relates to a vehicle control device that permits automatic stop of an engine when a vehicle engine stop condition is satisfied, and permits restart of the engine when an engine restart condition is satisfied, and The present invention relates to a vehicle control method.

  In recent years, for the purpose of improving the fuel efficiency of a vehicle, the engine is automatically stopped while the vehicle is stopped or just before the stop, and a so-called idle stop function that automatically restarts the engine upon the start operation by the driver is provided. Development of vehicle control devices is underway. For example, in the vehicle control apparatus described in Patent Document 1, braking is performed such that the negative pressure in the booster for assisting the braking operation by the driver is less than a predetermined threshold value while the engine is automatically stopped. When it is detected that the operation has been performed, the restart of the engine is permitted. The booster is connected to an intake manifold that generates a negative pressure when the engine is driven. The booster uses the pressure difference between the negative pressure generated in the intake manifold and the atmospheric pressure to boost the operating force of the brake pedal by the driver.

  By the way, when the amount of power stored in the battery mounted on the vehicle is small, and when the starter motor that operates when starting the engine is malfunctioning, it takes time to complete the engine restart, The engine may not be restarted. Such a state is also referred to as an “engine start failure state”.

  When the engine is in a start failure state, the driver may repeatedly press and release the brake pedal to prompt the engine to restart. Then, the negative pressure in the booster decreases due to the repetition of the depression and release operations of the brake pedal, and the braking force on the wheels decreases due to the lack of negative pressure in the booster. As a result, when the vehicle is located on a slope, the vehicle may begin to move against the driver's intention.

  In addition, when the engine is automatically stopped while the vehicle is decelerating, the negative pressure in the booster is reduced by adjusting the brake pedal operation amount for the purpose of adjusting the vehicle deceleration after the engine stops. There are things to do. In this case, the negative pressure in the booster may decrease immediately before the vehicle stops. For this reason, when the vehicle is located on a slope, there is a possibility that the vehicle cannot be stopped against the driver's intention due to insufficient braking force on the wheels due to insufficient negative pressure in the booster.

  Therefore, in the control device described in Patent Document 1, when an engine start failure state is detected, the brake actuator pump is operated to increase the braking force on the wheels. As a result, the movement of the vehicle against the driver's intention is suppressed. And the control for restarting an engine is performed in the state by which the safety | security of the vehicle was ensured in this way.

Japanese Patent Laid-Open No. 2003-13768

  By the way, in the vehicle control apparatus described in Patent Document 1, when an engine start failure state is detected, restart of the engine is permitted even while the braking force on the wheels is increased. Therefore, there is a possibility that the braking control for increasing the braking force on the wheels and the control for restarting the engine overlap in time. In this case, electric power is supplied from the battery to the brake actuator pump that operates to increase the braking force on the wheels and the starter motor that operates to start the engine, which increases the load on the battery. There was a risk.

  The present invention has been made in view of such circumstances. An object of the present invention is to provide a vehicle control device and a vehicle control method capable of restarting the engine while ensuring the safety of the vehicle while reducing the load of the battery mounted on the vehicle. .

In order to achieve the above object, the vehicle control device of the present invention permits the automatic stop of the engine (12) when the stop condition of the engine (12) of the vehicle is satisfied, and the engine (12). ) For the first control means (55, S12, S13) that permits the restart of the engine (12) when the restart condition is satisfied, and the wheels (FR, FL, RR, RL) provided in the vehicle And a second control means (55) for adjusting a braking force, wherein the vehicle applies a braking force corresponding to a fluid pressure generated therein to the wheels (FR, FL, RR, RL). A wheel cylinder (32a, 32b, 32c, 32d) applied to the wheel cylinder, and a brake actuator (31) for adjusting the fluid pressure in the wheel cylinder (32a, 32b, 32c, 32d). Brake actuator (31), said wheel cylinder (32a, 32 b, 32c, 32d) has a pump (42, 43) which operates to cause boosted fluid pressure in said second control means (55 , S32, S33) when the vehicle body speed (VS) of the vehicle is equal to or greater than a predetermined predetermined permission reference value (VSth) at which braking control involving the operation of the pump (42, 43) is permitted, When the engine (12) has not been started or when the engine (12) has failed to start, it is immediately detected that the engine (12) has failed to start, and the vehicle body speed (VS) of the vehicle is determined as the permission standard. In the case of less than the value (VSth), even if the engine (12) has failed to start a predetermined number of times set in advance, or even if the elapsed time since the restart is permitted exceeds a predetermined time, If the engine (12) is not started, it is detected that the engine (12) has failed to start, and after the engine (12) has been permitted to restart, In order to stop the vehicle, first braking control for increasing the braking force for the wheels (FR, FL, RR, RL) to a predetermined value set in advance is performed, and then, for the wheels (FR, FL, RR, RL). A second braking control for holding the braking force is performed, and the first control means (55, S12, S13, S31, S34) restarts the engine (12) during the execution of the first braking control. The gist is to prohibit starting and to allow restart of the engine (12) during execution of the second braking control.

  According to the above configuration, when engine start failure is detected, restart of the engine is prohibited, and the vehicle is stopped by increasing the braking force on the wheels. Thereafter, when the braking force on the wheels is maintained, the restart of the engine is permitted. That is, the time overlap between the braking control for increasing the braking force on the wheel and the control for restarting the engine is avoided. Further, even in a state where the negative pressure in the booster is reduced, the engine is restarted in a state where a braking force that can stop the vehicle is applied to the wheels. Therefore, it is possible to restart the engine while ensuring the safety of the vehicle while reducing the load on the battery mounted on the vehicle.

In the vehicle control apparatus according to the present invention, the second control means (55, S32, S33, S37) is configured so that an operation amount of a brake pedal (15) provided in the vehicle is during execution of the second braking control. It reduced it, or the brake pedal (15) when it is detected that in a non-operation state, the wheel (FR, FL, RR, RL) to reduce the braking force applied to permit movement of the vehicle Third braking control for adjusting the braking force on the wheels (FR, FL, RR, RL) so that the vehicle body speed (VS) of the vehicle is less than the preset permission reference value (VSth). Preferably it is done.

  A case where the amount of operation of the brake pedal is reduced or the brake pedal is not operated is considered to be a case where the driver permits the vehicle to move due to inertia. Therefore, in the present invention, when it is detected that the operation amount of the brake pedal is decreased or the brake pedal is not operated in a state where the vehicle is stopped by the second braking control, The braking force is reduced and the vehicle is allowed to move due to inertia. Then, for example, when the vehicle is located on a slope, the vehicle moves downward in the tilt direction. In other words, even when the engine is in an unstable starting state, the behavior of the vehicle can be in line with the driver's intention.

  When the engine is in a poor start state, there is a high possibility that the negative pressure in the booster has dropped. In this case, a sufficiently large braking force cannot be applied to the wheel by operating the brake pedal by the driver. Therefore, in the present invention, during the third braking control, the braking force on the wheels is adjusted so that the vehicle body speed is less than the permission reference value. Therefore, the engine can be restarted in a state in which the safety of the vehicle is ensured as much as it is possible to suppress the vehicle body speed from becoming too high.

In the vehicle control apparatus according to the present invention, the first control means (55, S12, S13, S31, S34) is configured so that an elapsed time from the start of the second braking control is a predetermined time or more. Then, the restart of the engine (12) is permitted .

The vehicle control method of the present invention includes a stop step (S12) for allowing automatic stop of the engine (12) when a stop condition for the engine (12) of the vehicle is satisfied, And a restart step (S13) for allowing restart of the engine (12) when a start condition is satisfied, wherein the vehicle has a braking force according to a fluid pressure generated therein. Cylinders (32a, 32b, 32c, 32d) for applying to the wheels (FR, FL, RR, RL) provided in the vehicle, and the fluid pressure in the wheel cylinders (32a, 32b, 32c, 32d) are adjusted A brake actuator (31) that performs fluid in the wheel cylinders (32a, 32b, 32c, 32d). Has a pump (42, 43) which operates to cause boosted, said restart step (S13), the vehicle body speed of the vehicle (VS) is the braking control with operation of the pump (42, 43) If the predetermined permission reference value (VSth) set in advance is exceeded, the engine (12) is immediately started if the engine (12) is not started or if the engine (12) fails to start. If the vehicle body speed (VS) of the vehicle is less than the permission reference value (VSth), the engine (12) has failed to start a predetermined number of times or restarted. If the engine (12) is not started even if the elapsed time from the time when the engine has been permitted is not less than a predetermined time, it is detected that the engine (12) has failed to start, and after the engine (12) is permitted to restart If the startup malfunction of the engine (12) is detected have, together to prohibit the restart of the engine (12), said wheel in order to stop the vehicle (FR, FL, RR, RL) and braking force for advance After the execution of the first step (S31, S32) for increasing the set predetermined value and the first step (S31, S32), the braking force for the wheels (FR, FL, RR, RL) is maintained. And a second step (S33, S34) for allowing restart of the engine (12).

  According to the said structure, the effect | action and effect equivalent to the said control apparatus of a vehicle can be acquired.

The block diagram which shows an example of the vehicle carrying the control apparatus of this embodiment. The block diagram which shows an example of a braking device. The map which shows an example of the relationship between a frequency | count reference value and a gradient equivalent value. The flowchart explaining an idle stop process routine. The flowchart explaining the engine restart processing routine (first half). The flowchart explaining the engine restart processing routine (second half). 6 is a timing chart showing changes in engine speed, vehicle body speed, number counter value, and target hydraulic pressure. The map which shows an example of the relationship between the time reference value and gradient equivalent value in another embodiment.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle).

  The vehicle according to the present embodiment automatically stops the engine in accordance with the establishment of a predetermined stop condition while the vehicle is running, and then improves the fuel efficiency performance and the emission performance. Has a so-called idle stop function for automatically restarting. Therefore, in this vehicle, the engine is automatically stopped while the vehicle is decelerated or stopped by the brake operation by the driver.

Next, an example of a vehicle having an idle stop function will be described.
As shown in FIG. 1, the vehicle has a plurality of (four in this embodiment) wheels (the right front wheel FR, the left front wheel FL, the right rear wheel RR, and the left rear wheel RL). It is a so-called front wheel drive vehicle that functions as a vehicle. Such a vehicle includes a driving force generator 13 having an engine 12 that generates a driving force corresponding to the amount of operation of the accelerator pedal 11 by the driver, and the driving force generated by the driving force generator 13 is applied to the front wheels FR and FL. And a driving force transmission device 14 for transmission. The vehicle is also provided with a braking device 16 for applying a braking force corresponding to the amount of operation of the brake pedal 15 by the driver to each wheel FR, FL, RR, RL.

  The driving force generator 13 includes a fuel injection device (not shown) that is disposed in the vicinity of an intake port (not shown) of the engine 12 and has an injector that injects fuel into the engine 12. The driving force generator 13 is driven based on control of an engine ECU 17 (also referred to as “engine electronic control device”) having a CPU, a ROM, a RAM, and the like (not shown). The engine ECU 17 is electrically connected to an accelerator opening sensor SE1 that is disposed in the vicinity of the accelerator pedal 11 and that detects an operation amount of the accelerator pedal 11 by the driver, that is, an accelerator opening. The engine ECU 17 calculates the accelerator opening based on the detection signal from the accelerator opening sensor SE1, and controls the driving force generator 13 based on the calculated accelerator opening.

  The driving force transmission device 14 controls the automatic transmission 18, the differential gear 19 that appropriately distributes the driving force transmitted from the output shaft of the automatic transmission 18, and transmits it to the front wheels FR and FL, and the automatic transmission 18. And an AT ECU (not shown). The automatic transmission 18 includes a fluid driving force transmission mechanism 20 having a torque converter 20a as an example of a fluid coupling, and a transmission mechanism 21.

  In the vehicle of this embodiment, a creep phenomenon occurs because the torque converter 20a is provided in the torque transmission path from the engine 12 to the drive wheels (front wheels FR, FL). This creep phenomenon is a phenomenon in which the vehicle slowly moves forward without depression of the accelerator pedal 11 when the shift lever is in the traveling position in a vehicle having the automatic transmission 18. Occasionally, the torque converter 20a transmits a slight driving force to the front wheels FR and FL. The slight power transmitted to the front wheels FR and FL is referred to as “creep torque”.

  As shown in FIGS. 1 and 2, the braking device 16 includes a hydraulic pressure generating device 28 having a master cylinder 25, a booster 26 and a reservoir 27, and a brake actuator 31 having two hydraulic pressure circuits 29 and 30 (in FIG. 2). 2). The hydraulic circuits 29 and 30 are connected to the master cylinder 25 of the hydraulic pressure generator 28, respectively. A wheel cylinder 32a for the right front wheel FR and a wheel cylinder 32d for the left rear wheel RL are connected to the first hydraulic circuit 29, and a wheel for the left front wheel FL is connected to the second hydraulic circuit 30. A cylinder 32b and a wheel cylinder 32c for the right rear wheel RR are connected.

  In the hydraulic pressure generator 28, the booster 26 is connected to an intake manifold (not shown) that generates a negative pressure when the engine 12 is driven. The booster 26 uses the pressure difference between the negative pressure generated in the intake manifold and the atmospheric pressure to boost the operating force of the brake pedal 15 by the driver.

  The master cylinder 25 generates a master cylinder pressure (hereinafter also referred to as “MC pressure”) as a fluid pressure in accordance with the operation of the brake pedal 15 (hereinafter also referred to as “brake operation”) by the driver. As a result, brake fluid as an example of fluid is supplied from the master cylinder 25 into the wheel cylinders 32 a to 32 d via the hydraulic circuits 29 and 30. Then, braking force according to the wheel cylinder pressure (also referred to as “WC pressure”) in the wheel cylinders 32a to 32d is applied to the wheels FR, FL, RR, and RL.

  In the brake actuator 31, the hydraulic circuits 29 and 30 are connected to the master cylinder 25 via connection paths 33 and 34, respectively. The connection paths 33 and 34 include normally open linear solenoid valves (adjustments). Valves) 35a and 35b are provided. The linear electromagnetic valves 35a and 35b include a valve seat, a valve body, an electromagnetic coil, and a biasing member (for example, a coil spring) that biases the valve body in a direction away from the valve seat. It is displaced according to the magnitude of the current supplied from the brake ECU 55 to the electromagnetic coil, that is, the current value. That is, the WC pressure in the wheel cylinders 32a to 32d is maintained at a hydraulic pressure corresponding to the current value for the linear electromagnetic valves 35a and 35b.

  In either one of the connection paths 33 and 34 (the connection path 33 in the present embodiment), a pressure for detecting the MC pressure in the master cylinder 25 is closer to the master cylinder 25 than the linear electromagnetic valve 35a. A sensor SE8 is provided. A detection signal corresponding to the MC pressure is output from the pressure sensor SE8 to the brake ECU 55.

  The first hydraulic circuit 29 includes a right front wheel path 36a connected to the wheel cylinder 32a and a left rear wheel path 36d connected to the wheel cylinder 32d. The second hydraulic circuit 30 includes a left front wheel path 36b connected to the wheel cylinder 32b and a right rear wheel path 36c connected to the wheel cylinder 32c. Further, in the paths 36a to 36d, pressure increasing valves 37a, 37b, 37c, and 37d that are normally open electromagnetic valves that operate when restricting the increase in the WC pressure in the wheel cylinders 32a to 32d, and the WC pressure are supplied. Pressure reducing valves 38a, 38b, 38c, and 38d, which are normally closed electromagnetic valves that operate when the pressure is reduced, are provided.

  Further, the hydraulic pressure circuits 29 and 30 include reservoirs 39 and 40 for temporarily storing brake fluid flowing out from the wheel cylinders 32a to 32d via the pressure reducing valves 38a to 38d, and a pump that operates based on the rotation of the motor 41. 42 and 43 are connected. The reservoirs 39 and 40 are connected to the pumps 42 and 43 via the suction flow paths 44 and 45 and are connected to the connection paths 33 and 34 via the master side flow paths 46 and 47 rather than the linear electromagnetic valves 35a and 35b. It is connected to the master cylinder 25 side. Further, the pumps 42 and 43 are connected to connection portions 50 and 51 between the pressure increasing valves 37a to 37d and the linear electromagnetic valves 35a and 35b in the hydraulic pressure circuits 29 and 30 through supply channels 48 and 49, respectively. Yes. When the motor 41 rotates, the pumps 42 and 43 suck the brake fluid from the reservoirs 39 and 40 and the master cylinder 25 side through the suction channels 44 and 45 and the master side channels 46 and 47, The brake fluid is discharged into the supply channels 48 and 49.

Next, the brake ECU 55 (also referred to as “brake electronic control device”) that controls the drive of the brake actuator 31 will be described.
As shown in FIG. 2, the input interface of the brake ECU 55 includes wheel speed sensors SE3, SE4, SE5, SE6 for detecting the wheel speed of each wheel FR, FL, RR, RL, and the longitudinal direction of the vehicle. An acceleration sensor (also referred to as “G sensor”) SE7 for detecting the acceleration at is electrically connected. In addition, a brake switch SW1 that is disposed in the vicinity of the brake pedal 15 and detects whether or not the brake pedal 15 is operated, and a pressure sensor SE8 are electrically connected to the input side interface of the brake ECU 55. Has been. The valves 35a, 35b, 37a to 37d, 38a to 38d, the motor 41, and the like are electrically connected to the output side interface of the brake ECU 55. The acceleration sensor SE7 outputs a signal that takes a positive value when the center of gravity of the vehicle moves backward, and a signal that takes a negative value when the center of gravity of the vehicle moves forward. Is output.

  The brake ECU 55 includes a digital computer including a CPU, ROM and RAM (not shown), a valve driver circuit (not shown) for operating the valves 35a, 35b, 37a to 37d, and 38a to 38d, and the motor 41. A motor driver circuit (not shown) for operating the motor. Various control processes (such as an idle stop process described later), various maps (such as the map shown in FIG. 3), various threshold values, and the like are stored in advance in the ROM of the digital computer. The RAM also stores various types of information that can be appropriately rewritten while an ignition switch (not shown) of the vehicle is on.

  In the vehicle of this embodiment, ECUs including the engine ECU 17 and the brake ECU 55 are connected to each other via a bus 56 so that various information and various control commands can be transmitted and received as shown in FIG. For example, from the engine ECU 17, information related to the accelerator opening of the accelerator pedal 11, information related to the success / failure of the restart of the engine 12, and the like are appropriately transmitted to the brake ECU 55. On the other hand, from the brake ECU 55, a stop permission command for permitting an automatic stop of the engine 12, a restart permission command for permitting an automatic restart of the engine 12, and a restart for prohibiting the restart. A start prohibition command or the like is transmitted to the engine ECU 17.

Next, various maps stored in the ROM of the brake ECU 55 will be described with reference to FIG.
Even if the engine 12 is to be automatically restarted, the engine 12 may not be restarted due to an insufficient amount of power stored in a battery (not shown) mounted on the vehicle or a starter motor (not shown) malfunctioning. is there. In such a case, control for restarting the engine 12 is repeatedly executed. If the engine 12 cannot be restarted even if the control for restarting the engine 12 is continuously performed, it is determined that the engine 12 is in a start failure state.

  The map shown in FIG. 3 is used to set the number of times reference value CTth, which is an example of a reference value for determining whether or not the engine 12 is in a start failure state, to a value according to the slope of the road surface on which the vehicle is located. It is an example of a map. The number reference value CTth is an upper limit value of the number of times that the control process on the engine ECU 17 side for restarting the engine 12 is continuously executed. The gradient equivalent value Ag is a value corresponding to the gradient of the road surface on which the vehicle is located. That is, when the gradient equivalent value Ag is substantially “0 (zero)”, the road surface on which the vehicle is located is a road surface substantially parallel to the horizontal plane. The road surface when the gradient equivalent value Ag is a positive value is an uphill road, and the road surface when the gradient equivalent value Ag is a negative value is a downhill road.

  In the present embodiment, as shown in FIG. 3, the count reference value CTth is set to a larger value when the road surface gradient is a gentle gradient than when the gradient is a steep gradient. For example, when the gradient equivalent value Ag is “0”, the frequency reference value CTth is set to the maximum value CTmax (for example, 5 times). When the gradient equivalent value Ag is less than “0” and larger than the first value Ag1 (<0 (zero)), the number reference value CTth is set to a smaller value as the gradient equivalent value Ag becomes smaller. The Similarly, when the gradient equivalent value Ag is larger than “0” and less than the second value Ag2 (> 0 (zero)), the number reference value CTth is set to a smaller value as the gradient equivalent value Ag becomes larger. The When the gradient equivalent value Ag is equal to or less than the first value Ag1, and when the gradient equivalent value Ag is equal to or greater than the second value Ag2, the frequency reference value CTth is set to the minimum value CTmin (for example, twice). The The absolute value of the second value Ag2 is equal to the absolute value of the first value Ag1.

  Next, an idle stop processing routine executed by the brake ECU 55 of the present embodiment will be described based on the flowchart shown in FIG. This idle stop processing routine is a processing routine for setting a timing at which automatic stop of the engine 12 is permitted, a timing at which automatic restart of the engine 12 is permitted, and the like.

  Now, the brake ECU 55 executes an idle stop processing routine every predetermined period (for example, 0.01 second period) set in advance. In this idle stop processing routine, the brake ECU 55 acquires the MC pressure Pmc in the master cylinder 25 based on the detection signal from the pressure sensor SE8 (step S10). Subsequently, the brake ECU 55 determines whether or not the engine 12 is stopped based on the information received from the engine ECU 17 (step S11).

  If the determination result is negative, the brake ECU 55 executes an engine stop process because the engine 12 is being driven (step S12). That is, the brake ECU 55 allows the vehicle body speed of the vehicle to be equal to or lower than a predetermined speed (for example, 20 km / h) set in advance, and the MC pressure Pmc acquired in step S10 permits the engine 12 to be automatically stopped. If the value is equal to or greater than the determination value for determining whether or not the vehicle is not, it is determined that the driver has an intention to stop the vehicle. Then, the brake ECU 55 transmits a stop permission command to the engine ECU 17. Therefore, in the present embodiment, step S12 corresponds to a stop step for permitting automatic stop of the engine 12 when the stop condition of the engine 12 is satisfied. Thereafter, the brake ECU 55 once ends the idle stop processing routine.

  On the other hand, when the determination result of step S11 is affirmative, the brake ECU 55 performs an engine restart process because the engine 12 is stopped (step S13). In this engine restart process, as will be described in detail later, the braking force for the wheels FR, FL, RR, RL is adjusted, or a restart permission command or a restart prohibition command is transmitted to the engine ECU 17. In this regard, in this embodiment, step S13 corresponds to a restart step that permits automatic restart of the engine 12 when the restart condition of the engine 12 is satisfied. The brake ECU 55 functions as a first control unit. Then, after executing the engine restart process, the brake ECU 55 once ends the idle stop process routine.

  Next, the engine restart process (engine restart process routine) will be described based on the flowcharts shown in FIGS. 5 and 6 and the timing chart shown in FIG. FIG. 7 is a timing chart when the vehicle travels on a slope.

  In the engine restart process routine, the brake ECU 55 determines whether or not the MC pressure Pmc acquired in step S10 is less than a preset MC pressure reference value Pmcth (step S20). The MC pressure reference value Pmcth is a determination value for determining whether or not restart of the engine 12 is permitted, and is a determination value for determining whether or not automatic stop of the engine 12 is permitted. Is set to a smaller value. The MC pressure reference value Pmcth may be set to a value according to the gradient of the road surface on which the vehicle is located.

  If the determination result in step S20 is negative (Pmc ≧ Pmcth), the brake ECU 55 resets the counter value CT described later to “0 (zero)” because the restart condition of the engine 12 is not satisfied. (Step S21), the engine restart processing routine is terminated. On the other hand, when the determination result of step S20 is affirmative (Pmc <Pmcth), the brake ECU 55 transmits a restart permission command to the engine ECU 17 because the restart condition of the engine 12 is satisfied (step S22). The engine ECU 17 that has received the restart permission command performs control for starting the engine 12. Then, the engine ECU 17 outputs information on the success / failure of the restart of the engine 12 to the brake ECU 55.

  Subsequently, the brake ECU 55 determines whether or not the restart of the engine 12 has failed based on the information received from the engine ECU 17 after the transmission of the restart permission command (step S23). If the determination result is negative, the brake ECU 55 proceeds to step S21 described above because the engine 12 has been successfully restarted. On the other hand, when the determination result of step S23 is affirmative, the brake ECU 55 acquires the vehicle body speed VS of the vehicle because the restart of the engine 12 has failed (step S24). Specifically, the brake ECU 55 calculates the wheel speed of each wheel FL, FR, RL, RR based on the detection signal from each wheel speed sensor SE3 to SE6, and the wheel FL, FR, RL, RR of each wheel FL, FR, RL, RR is calculated. The wheel acceleration is obtained by time-differentiating at least one of the wheel speeds. Then, the brake ECU 55 integrates the wheel acceleration with respect to the vehicle body speed acquired at the previous timing, and sets the integration result as the vehicle body speed VS. Therefore, in the present embodiment, the brake ECU 55 also functions as a vehicle body speed acquisition unit.

  Then, the brake ECU 55 determines whether or not the vehicle body speed VS acquired in step S24 is less than a vehicle body speed reference value VSth (for example, 7 km / h) as a preset vehicle body speed threshold value and a control threshold value (step 7). S25). The vehicle body speed reference value VSth is a reference value for determining whether or not the execution of the braking control for operating the pumps 42 and 43 of the brake actuator 31 is permitted. Note that examples of the braking control that accompanies the operation of the pumps 42 and 43 include anti-lock brake control and skid prevention control (ESC: Electronic Stability Control).

  If the determination result of step S25 is negative (VS ≧ VSth), the brake ECU 55 proceeds to step S31 described later. On the other hand, when the determination result in step S25 is affirmative (VS <VSth), the brake ECU 55 increments the count counter value CT, which is a measured value of the number of times that the restart of the engine 12 has failed continuously, by “1”. (Step S26). Subsequently, the brake ECU 55 acquires an acceleration (hereinafter also simply referred to as “vehicle body acceleration”) G in the longitudinal direction of the vehicle based on the detection signal from the acceleration sensor SE7 (step S27). Then, the brake ECU 55 obtains a vehicle body speed differential value (actual vehicle acceleration) DVS by time differentiation of the vehicle body speed VS acquired in step S24 (step S28). The brake ECU 55 may use the wheel acceleration acquired during the process in step S24 as the vehicle body speed differential value DVS.

  Subsequently, the brake ECU 55 subtracts the vehicle body speed differential value DVS calculated in step S28 from the vehicle body acceleration G calculated in step S27, and sets the subtraction result as a gradient equivalent value Ag (step S29). Here, the vehicle body acceleration G calculated based on the detection signal from the acceleration sensor SE7 includes an actual acceleration component of the vehicle and an acceleration component corresponding to the gradient of the road surface on which the vehicle travels. The “actual acceleration component of the vehicle” is a vehicle body speed differential value DVS that is a differential value of the vehicle body speed VS, and the gradient equivalent value Ag is obtained by removing the actual acceleration component of the vehicle from the vehicle body acceleration G. The Therefore, in the present embodiment, the brake ECU 55 also functions as a gradient equivalent value acquisition unit.

  Then, the brake ECU 55 sets the number-of-times reference value CTth corresponding to the gradient equivalent value Ag acquired in step S29 based on the map shown in FIG. Then, the brake ECU 55 determines whether or not the number counter value CT updated in step S26 is greater than or equal to the set collection reference value CTth (step S30). If this determination is negative (CT <CTth), the brake ECU 55 proceeds to step S22 described above. On the other hand, if the determination result in step S30 is affirmative (CT ≧ CTth), the brake ECU 55 determines that the engine 12 is in a start failure state, and the process proceeds to step S31 described later.

  In step S31, the brake ECU 55 transmits a restart prohibition command to the engine ECU 17. The engine ECU 17 that has received the restart prohibition command does not perform control for restarting the engine 12. Subsequently, the brake ECU 55 performs a first braking control process for operating the pumps 42 and 43 (that is, the motor 41) of the brake actuator 31 and the linear electromagnetic valves 35a and 35b in order to stop the vehicle (step). S32). Therefore, in the present embodiment, the first step is configured by steps S31 and S32. Also, the brake ECU 55 that performs the first braking control that increases the braking force on the wheels FR, FL, RR, and RL to stop the vehicle also functions as the second control means.

  When the first braking control process ends, the brake ECU 55 performs a second braking control process for maintaining the WC pressure Pwc in each of the wheel cylinders 32a to 32d (step S33). Specifically, the brake ECU 55 stops the pumps 42 and 43 of the brake actuator 31 and operates the linear electromagnetic valves 35a and 35b to maintain the WC pressure Pwc in the wheel cylinders 32a to 32d. Subsequently, the brake ECU 55 stops the operation of the pumps 42 and 43, and therefore transmits a restart permission command to the engine ECU 17 (step S34). The engine ECU 17 that has received the restart permission command appropriately performs control for restarting the engine 12. Accordingly, in the present embodiment, the second step is configured by steps S33 and S34.

  Here, as shown in the timing chart of FIG. 7, when the engine 12 is automatically stopped at the first timing t1, the engine rotational speed Ne rapidly decreases. In addition, since creep torque is not transmitted to the front wheels FR and FL, which are drive wheels, the rate of change of the vehicle body speed VS is also increased. Then, when the restart condition of the engine 12 is satisfied at the second timing t2 when the vehicle body speed VS becomes less than the vehicle body speed reference value VSth (more specifically, the vehicle stops), the engine 12 is restarted. Is controlled.

  However, if the restart of the engine 12 fails, the number counter value CT is incremented by “1”. Then, at the third timing t3 after the second timing t2, since the vehicle body speed VS is less than the vehicle body speed reference value VSth, the control for restarting the engine 12 is performed again. If the restart of the engine 12 fails again this time, the number counter value CT is incremented by “1” again. At this time, when the count counter value CT becomes equal to or greater than the count reference value Ctth, it is determined that the engine 12 is in a start failure state, and restart of the engine 12 is prohibited. On the other hand, when the count counter value CT is less than the count reference value Ctth, it is not determined that the engine 12 is in the start malfunction state at this timing.

  That the control for restarting the engine 12 is repeatedly performed means that the MC pressure Pmc in the master cylinder 25 is lowered, that is, the braking force for the wheels FR, FL, RR, RL is reduced. Means. This is because the condition for permitting restart of the engine 12 includes that the MC pressure Pmc is less than the MC pressure reference value Pmcth (see FIG. 5). Therefore, when the road surface on which the vehicle is located is a downhill road, the vehicle may move forward due to insufficient braking force on the wheels FR, FL, RR, and RL due to the decrease in the MC pressure Pmc. Further, when the road surface on which the vehicle is located is an uphill road, the vehicle may move backward.

  When the vehicle speed VS of the vehicle becomes equal to or higher than the vehicle speed reference value VSth due to the movement of the vehicle due to such inertia, the restart of the engine 12 is prohibited (fourth timing t4). This is because when the vehicle body speed VS becomes equal to or higher than the vehicle body speed reference value VSth, execution of braking control is permitted such that the pumps 42 and 43 of the brake actuator 31 are operated. That is, there is a possibility that the control for restarting the engine 12 and the braking control accompanied by the operation of the pumps 42 and 43 may overlap in time.

  When the restart of the engine 12 is prohibited, the WC pressure Pwc (shown by broken lines in FIG. 7) in the wheel cylinders 32a to 32d for the wheels FR, FL, RR, and RL becomes the target hydraulic pressure Pwcth. In addition, the pumps 42 and 43 of the brake actuator 31 and the linear electromagnetic valves 35a and 35b are operated (first braking control). That is, the braking force for the wheels FR, FL, RR, RL is increased to stop the vehicle.

  Thereafter, at the fifth timing t5 when the WC pressure Pwc in the wheel cylinders 32a to 32d becomes approximately equal to the target hydraulic pressure Pwcth, the braking control is switched from the first braking control to the second braking control. Then, in the brake actuator 31, the operation of the pumps 42, 43 is stopped, and the braking force for the wheels FR, FL, RR, RL is held by the operation of the linear electromagnetic valves 35a, 35b (second braking control). . Then, restart of the engine 12 is permitted. When the restart condition of the engine 12 is satisfied in this state, control for restarting the engine 12 is performed (sixth timing t6).

  Returning to the flowchart of FIG. 6, the brake ECU 55 determines whether or not the restart of the engine 12 has been successful based on the information received from the engine ECU 17 after transmission of the restart permission command (step S34) (step S35). ). If this determination result is affirmative, the brake ECU 55 proceeds to step S21 described above because the engine 12 has been restarted. On the other hand, if the determination result in step S35 is negative, the brake ECU 55 determines whether or not the brake switch SW1 is turned off because the engine 12 has not been restarted, that is, whether the operation of the brake pedal 15 has been canceled. It is determined whether or not (step S36). If this determination result is negative (SW1 = on), the brake ECU 55 proceeds to step S35 described above.

  On the other hand, if the determination result in step S36 is affirmative (SW1 = off), the brake ECU 55 determines that the driver has permitted the movement of the vehicle due to inertia, and performs a third braking control process (step S37). . Specifically, even if the vehicle moves due to inertia, the brake ECU 55 adjusts the WC pressure Pwc in the wheel cylinders 32a to 32d so that the vehicle body speed VS of the vehicle does not exceed the vehicle body speed reference value VSth. . That is, the brake ECU 55 adjusts the current value for the linear electromagnetic valves 35a and 35b while not operating the pumps 42 and 43. At this time, the current value for the linear electromagnetic valves 35a and 35b is set to a larger value as the gradient of the road surface on which the vehicle is located is steeper. That is, in the third braking control, the braking force on the wheel is not increased, although it is decreased. Therefore, in the present embodiment, the vehicle body speed reference value VSth is also the permission reference value. Even if the braking force applied to the wheels FR, FL, RR, and RL is reduced in this way, the vehicle may not move depending on the gradient of the road surface.

  Then, the brake ECU 55 determines whether or not the restart of the engine 12 is successful based on the information received from the engine ECU 17 after the process of step S37 (step S38). If this determination result is affirmative, the brake ECU 55 proceeds to step S21 described above because the engine 12 has been restarted. On the other hand, if the determination result in step S38 is negative, the brake ECU 55 determines whether the brake switch SW1 is turned on because the engine 12 has not been restarted, that is, whether the brake pedal 15 has been operated again. Is determined (step S39). If this determination is negative (SW1 = off), the brake ECU 55 proceeds to step S38 described above. On the other hand, if the determination result in step S39 is affirmative (SW1 = on), the brake ECU 55 proceeds to step S31 described above. That is, the restart of the engine 12 is prohibited (step S31), and then a first braking control process for stopping the vehicle is executed (step S32). When the vehicle stops, the second braking control process is executed (step S33), and the restart of the engine 12 is permitted (step S34).

  When the engine 12 is restarted in a state where the braking force is applied to the wheels FR, FL, RR, and RL by the second braking control or the third braking control, the brake ECU 55 includes a linear solenoid valve. The current values for 35a and 35b are gradually reduced (see FIG. 7).

Therefore, in this embodiment, the following effects can be obtained.
(1) When a start failure of the engine 12 is detected, the restart of the engine 12 is prohibited and the braking force for the wheels FR, FL, RR, RL is increased to stop the vehicle. Thereafter, when the braking force for the wheels FR, FL, RR, RL is maintained, restart of the engine 12 is permitted. That is, the time overlap between the braking control of the brake actuator 31 for increasing the braking force on the wheels FR, FL, RR, and RL and the driving control on the driving force generator 13 side for restarting the engine 12. Is avoided. Further, even when the negative pressure in the booster 26 is reduced, the engine 12 is restarted in a state where a braking force that can stop the vehicle is applied to the wheels FR, FL, RR, and RL. Will be done. Therefore, the engine 12 can be restarted while ensuring the safety of the vehicle while reducing the load on a battery (not shown) mounted on the vehicle.

  (2) In order to increase the braking force for the wheels FR, FL, RR, RL using the brake actuator 31, it is necessary to operate the pumps 42, 43 (that is, the motor 41). When the pumps 42 and 43 are operated, the power consumption at the brake actuator 31 increases. If the engine 12 is to be restarted in this state, the load on the vehicle battery becomes very large. In particular, one of the causes that cause the engine 12 to malfunction is that the amount of power stored in the battery is low. Therefore, when drive control on the drive force generator 13 side for restarting the engine 12 is performed during braking control for operating the pumps 42 and 43, a starter motor that operates to start the engine 12 ( There is a possibility that a sufficient amount of electric power supply for (not shown) cannot be secured. That is, the engine 12 cannot be easily restarted by simply consuming the stored amount of battery power.

  In this regard, in the present embodiment, control for restarting the engine 12 is not performed during braking control for operating the pumps 42 and 43. Therefore, the load on the battery can be reduced. Further, when the engine 12 is restarted, sufficient power can be supplied to the starter motor, and thus the engine 12 can be restarted quickly.

  (3) When it is detected that the brake pedal 15 is not operated while the vehicle is stopped by the second braking control, it is determined that the driver has permitted the movement of the vehicle due to inertia. . And the braking force with respect to wheel FR, FL, RR, RL is decreased. Then, when the vehicle is located on the slope, the vehicle moves downward in the inclination direction. In other words, even when the engine 12 is in a poor starting state, the behavior of the vehicle can be made in line with the driver's intention.

  (4) When the engine 12 is in a start-up malfunction state, there is a high possibility that the negative pressure in the booster 26 has decreased. In this case, since the MC pressure Pmc in the master cylinder 25 cannot be sufficiently increased, a sufficiently large braking force cannot be applied to the wheels FR, FL, RR, RL by operating the brake pedal 15 by the driver. Therefore, in the present embodiment, during the third braking control, the braking force for the wheels FR, FL, RR, RL is adjusted so that the vehicle body speed VS does not exceed the vehicle body speed reference value VSth. Therefore, the control for restarting the engine 12 can be performed in a state in which the safety of the vehicle is ensured as much as the vehicle body speed VS of the vehicle can be prevented from becoming too high.

  Depending on the road surface on which the vehicle is located, the vehicle may not move even if the third braking control is executed. In addition, the “movement due to the inertia of the vehicle” in the present embodiment refers to the movement of the vehicle caused by a force corresponding to the gradient (also referred to as “gradient acceleration”) applied to the vehicle located on the slope. It is a concept that includes

  (5) In the present embodiment, at the time of the third braking control, the pumps 42 and 43 are not operated, so that the restart of the engine 12 is permitted. Therefore, there is a possibility that the engine 12 is restarted when the operation of the brake pedal 15 by the driver is canceled. That is, the engine 12 can be restarted at a timing that does not make the driver feel uncomfortable.

  (6) Even during the third braking control, when the operation of the brake pedal 15 by the driver is detected, the braking force for the wheels FR, FL, RR, RL is increased to stop the vehicle. This is because the fact that the brake pedal 15 is operated determines that the driver is willing to stop the vehicle. Therefore, the vehicle can be stopped according to the driver's intention.

  (7) When the braking force for the wheels FR, FL, RR, and RL is increased as described above, restart of the engine 12 is prohibited. Therefore, an increase in battery load can be suppressed.

  (8) The count reference value CTth is set to a larger value when the gradient of the road surface on which the vehicle is located is a gentle gradient than when the gradient is a steep gradient. Therefore, when the vehicle is difficult to accelerate, that is, when the gradient equivalent value Ag is close to “0 (zero)”, the number of retries for restarting the engine 12 increases. This is because, even if the braking force on the wheels FR, FL, RR, RL is reduced due to a decrease in the negative pressure in the booster 26, the vehicle body is in a case where the gradient equivalent value Ag is close to “0 (zero)”. This is because the speed VS is not easily increased. In this way, when the safety of the vehicle can be ensured, it is possible to delay the determination as to whether or not the engine 12 is in a start failure state as much as possible. That is, the possibility that the engine 12 can be restarted before the execution of the first braking control can be increased.

  (9) In this embodiment, even if the number counter value CT is less than the collection reference value CTth, the restart of the engine 12 is prohibited when the vehicle body speed VS is equal to or higher than the vehicle body speed reference value VSth. At the same time, the brake actuator 31 is driven to increase the braking force on the wheels FR, FL, RR, RL. This is because when the vehicle body speed VS of the vehicle becomes equal to or higher than the vehicle body speed reference value VSth, the execution of the braking control with the operation of the pumps 42 and 43 is permitted. This is because there is a possibility of overlap in time. Therefore, in the present embodiment, it is possible to contribute to a reduction in the possibility that the braking control accompanied by the operation of the pumps 42 and 43 and the control for restarting the engine 12 overlap in time.

The embodiment may be changed to another embodiment as described below.
In the embodiment, the count reference value CTth may be a preset value (for example, 3) regardless of the magnitude of the gradient equivalent value Ag.

  Further, the number of restart failures of the engine 12, that is, the number counter value CT may not be counted. In this case, when the vehicle body speed VS becomes equal to or higher than the vehicle body speed reference value VSth while the restart failure of the engine 12 is repeated, it is determined that the engine 12 is in a start failure state.

  -In embodiment, when the gradient information regarding the road surface gradient (namely, the information regarding gradient equivalent value Ag) is memorize | stored in the navigation apparatus mounted in a vehicle, even if gradient equivalent value Ag is acquired from a navigation apparatus. Good.

  In the embodiment, the elapsed time after the restart condition of the engine 12 is satisfied (in the above embodiment, after step S20 becomes affirmative) is measured, and the elapsed time becomes equal to or greater than the time reference value. When the engine 12 is not restarted, it may be determined that the engine 12 is in a start-up malfunction state. In this case, it is preferable to prepare the map shown in FIG. This map is a map for setting the time reference value Tth to a value corresponding to the gradient equivalent value Ag. That is, the time reference value Tth is set to a larger value when the slope of the road surface is a gentle slope than when the slope is a steep slope.

  When the vehicle is moving backward, generally, braking control using the brake actuator 31 is not performed. In such a vehicle, when the vehicle moves backward, the determination process in step S25 may be omitted. Even in this configuration, the braking control accompanied by the operation of the pumps 42 and 43 of the brake actuator 31 and the driving control on the driving force generator 13 side for restarting the engine 12 overlap in time. Can be avoided.

  In the embodiment, in step S36, it may be determined whether or not the operation amount of the brake pedal 15 has decreased. The operation amount of the brake pedal 15 is estimated based on the fluctuation of the MC pressure Pmc calculated based on the detection signal from the pressure sensor SE8.

Similarly, in step S39, it may be determined whether the amount of operation of the brake pedal 15 has increased.
In the embodiment, in the third braking control, the wheels FR, FL, and so on are set so that the vehicle body speed VS is equal to or less than the permission reference value set to a value smaller than the vehicle body speed reference value (control threshold value) VSth. You may adjust the braking force with respect to RR and RL.

  -During the execution of the third braking control, the slope of the road surface on which the vehicle travels may change. In particular, when the road gradient becomes steeper than the gradient at the start of the third braking control, the vehicle body speed VS of the vehicle becomes high. This is because the current value for the linear electromagnetic valves 35a and 35b is set by the gradient of the road surface at the start of the third braking control. In this way, when the vehicle body speed VS becomes equal to or higher than the vehicle body speed reference value VSth during the execution of the third braking control, a restart prohibition command is issued to the engine regardless of whether the driver operates the brake pedal 15 or not. The first braking control process may be performed while being transmitted to the ECU 17. If comprised in this way, it will avoid that the braking control accompanying the action | operation of the pumps 42 and 43 of the brake actuator 31 and the drive control by the side of the driving force generator 13 for restarting the engine 12 overlap in time. it can.

  Further, when the vehicle body speed VS becomes equal to or higher than the vehicle body speed reference value VSth during the execution of the third braking control, the brake actuator 31 is driven so that the vehicle body speed VS becomes less than the vehicle body speed reference value VSth. May be. However, it is preferable to prohibit the restart of the engine 12 while the brake actuator 31 is being driven.

  In the embodiment, when the operation of the brake pedal 15 by the driver is canceled during the second braking control, the braking force for the wheels FR, FL, RR, RL may be set to “0 (zero)”. Thereafter, when the vehicle body speed VS becomes equal to or higher than the vehicle body speed reference value VSth, the first braking control may be performed. The engine 12 may be allowed to restart while the braking force on the wheels FR, FL, RR, RL is “0 (zero)”.

-In embodiment, you may acquire the vehicle body speed VS from the navigation apparatus mounted in a vehicle.
In the embodiment, in the first braking control process, the target hydraulic pressure Pwcth may be set to a higher pressure when the gradient equivalent value Ag is larger than when the gradient equivalent value Ag is smaller.

  In the embodiment, when the first braking control process and the second braking control process are executed in response to the determination result of step S39 being affirmative (SW1 = on), the second braking control is performed. Alternatively, the restart permission command may be transmitted to the engine ECU 17 after the elapsed time from the start of the engine reaches a predetermined time (for example, 10 seconds) set in advance. In this case, during the predetermined time after the execution of the second braking control, the electric power stored in the battery is not consumed for restarting the engine 12, and the amount of power stored in the battery can be slightly increased. As the amount of power stored in the battery increases in this way, there is a high possibility that an engine start failure state caused by a shortage of the amount of power stored in the battery can be resolved.

  When the vehicle includes an electric parking brake device, the electric parking brake device may be used instead of the brake actuator 31 in each of the first to third braking control processes. An electric parking brake device may be used together.

Next, the technical idea that can be grasped from the above embodiment and another embodiment will be added below.
(A) The first control means (55, S12, S13, S31, S34)
The number of executions of restart of the engine (12) since the restart of the engine (12) is permitted or the elapsed time since the restart of the engine (12) is permitted When the engine (12) is not restarted even when the value (CTth) or the time reference value (Tth) is exceeded, the vehicle control device detects a start failure of the engine (12).

(B) vehicle body speed acquisition means (55, S24) for acquiring the vehicle body speed (VS) of the vehicle;
The first control means (55, S12, S13, S31, S34)
Even if the vehicle body speed (VS) acquired by the vehicle body speed acquisition means (55, S24) exceeds the preset vehicle body speed threshold (VSth) after the restart of the engine (12) is permitted, the engine ( 12. A vehicle control device that detects a start failure of the engine (12) when 12) is not restarted.

(C) The vehicle includes a wheel cylinder (32a, 32b, 32c, 32d) that applies a braking force corresponding to the fluid pressure generated inside to the wheel (FR, FL, RR, RL), and the wheel cylinder (32a , 32b, 32c, 32d), and a brake actuator (31) for adjusting the fluid pressure in the fluid,
The brake actuator (31) includes a pump (42, 43) that operates to increase the fluid pressure in the wheel cylinder (32a, 32b, 32c, 32d), and the wheel cylinder (32a, 32b, 32c, 32d). ) And adjusting valves (35a, 35b) that operate to adjust the fluid pressure in the
The vehicle control apparatus according to claim 1, wherein the permission reference value is set to a value equal to or less than a control threshold value (VSth) for permitting execution of braking control accompanied by operation of the pump (42, 43).

  DESCRIPTION OF SYMBOLS 12 ... Engine, 15 ... Brake pedal, 31 ... Brake actuator, 32a-32d ... Wheel cylinder, 35a, 35b ... Linear solenoid valve as adjustment valve, 42, 43 ... Pump, 55 ... 1st control means, 2nd Control means, brake ECU as vehicle speed acquisition means, FR, FL, RR, RL ... wheel, CT ... count counter value as number of executions, CTth ... time reference value, Tth ... time reference value, VS ... vehicle speed, VSth: permission reference value, vehicle body speed threshold value, vehicle body speed reference value as a control threshold value.

Claims (4)

When the stop condition of the engine (12) of the vehicle is satisfied, the automatic stop of the engine (12) is permitted, and when the restart condition of the engine (12) is satisfied, the engine (12) is restarted. First control means (55, S12, S13) for permitting start;
In a vehicle control device comprising: a second control means (55) for adjusting a braking force for wheels (FR, FL, RR, RL) provided in the vehicle;
The vehicle includes a wheel cylinder (32a, 32b, 32c, 32d) that applies braking force to the wheel (FR, FL, RR, RL) according to a fluid pressure generated inside, and the wheel cylinder (32a, 32b). , 32c, 32d), and a brake actuator (31) for adjusting the fluid pressure in
The brake actuator (31) has a pump (42, 43) that operates to increase the fluid pressure in the wheel cylinder (32a, 32b, 32c, 32d),
The second control means (55, S32, S33)
When the vehicle body speed (VS) of the vehicle is equal to or higher than a predetermined permission reference value (VSth) that is set in advance so that braking control involving operation of the pumps (42, 43) is permitted, the engine (12) is started. If the engine (12) fails to start, it is immediately detected that the engine (12) has failed to start, and the vehicle body speed (VS) is less than the permission reference value (VSth). If the engine (12) fails to start a predetermined number of times set in advance, or if the engine (12) is not started even if the elapsed time after allowing the restart exceeds a predetermined time, It detects that the engine (12) has started badly,
When a malfunction of the engine (12) is detected after permission to restart the engine (12),
In order to stop the vehicle, first braking control is performed to increase the braking force for the wheels (FR, FL, RR, RL) to a predetermined value set in advance, and then the wheels (FR, FL, RR, RL) are performed. Second braking control to maintain the braking force against
The first control means (55, S12, S13, S31, S34)
During the execution of the first braking control, restart of the engine (12) is prohibited,
A vehicle control device that permits restart of the engine (12) during execution of the second braking control. The second control means (55, S32, S33, S37)
During the execution of the second braking control, when it is detected that the operation amount of the brake pedal (15) provided in the vehicle is reduced or the brake pedal (15) is in a non-operating state,
The vehicle is allowed to move by reducing the braking force applied to the wheels (FR, FL, RR, RL) so that the vehicle body speed (VS) of the vehicle is less than the preset permission reference value (VSth). 2. The vehicle control device according to claim 1, wherein third braking control for adjusting a braking force to the wheels (FR, FL, RR, RL) is performed. The first control means (55, S12, S13, S31, S34) is configured so that the engine (12) is set after an elapsed time from the start of the second braking control becomes a predetermined time or more. The vehicle control device according to claim 1, wherein restart of the vehicle is permitted. A stop step (S12) for allowing automatic stop of the engine (12) when a stop condition of the engine (12) of the vehicle is satisfied;
A restarting step (S13) for allowing restart of the engine (12) when a restart condition of the engine (12) is satisfied,
The vehicle includes a wheel cylinder (32a, 32b, 32c, 32d) that applies a braking force corresponding to a fluid pressure generated therein to wheels (FR, FL, RR, RL) provided in the vehicle, and the wheel cylinder. A brake actuator (31) for adjusting the fluid pressure in (32a, 32b, 32c, 32d),
The brake actuator (31) has a pump (42, 43) that operates to increase the fluid pressure in the wheel cylinder (32a, 32b, 32c, 32d),
The restarting step (S13)
When the vehicle body speed (VS) of the vehicle is equal to or higher than a predetermined permission reference value (VSth) that is set in advance so that braking control involving operation of the pumps (42, 43) is permitted, the engine (12) is started. If the engine (12) fails to start, it is immediately detected that the engine (12) has failed to start, and the vehicle body speed (VS) is less than the permission reference value (VSth). If the engine (12) fails to start a predetermined number of times set in advance, or if the engine (12) is not started even if the elapsed time after allowing the restart exceeds a predetermined time, It detects that the engine (12) has started badly,
If the startup malfunction of the engine (12) is detected after the allowed restart of the engine (12), along with to prohibit the restart of the engine (12), said wheel in order to stop the vehicle (FR, A first step (S31, S32) for increasing the braking force for FL, RR, RL) to a predetermined value set in advance;
After the execution of the first step (S31, S32), a second step (S33) for maintaining the braking force on the wheels (FR, FL, RR, RL) and allowing the engine (12) to restart. , S34), and a vehicle control method.

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