JP2020157891A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device which improves steering stability in braking from a state where an engine is stopped during traveling.SOLUTION: A vehicle control device provided on a vehicle 1 includes: an engine 10; a front wheel driving mechanism and a rear wheel driving mechanism which transmit output of the engine to each of front wheels and rear wheels of a vehicle; a restraining force variable mechanism 80 which can change a restraining force of the front wheel driving mechanism and the rear wheel driving mechanism; and a braking device which generates a braking force in the front wheels and the rear wheels. The vehicle control device includes: an engine control device 110 which automatically stops the engine when a predetermined engine stop condition is satisfied during traveling of the vehicle; and a restraining force control device 120 which increases a restraining force of the restraining force variable mechanism when a predetermined sudden braking condition is satisfied during traveling of the vehicle and stopping of the engine.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle control device provided in an AWD vehicle having a function of automatically stopping an engine during traveling.

For example, it is known that a four-wheel drive vehicle is equipped with an all-wheel drive (AWD) system for driving front and rear wheels, and changes the driving state of at least one of the front and rear wheels according to the running state of the vehicle. Has been done.
Further, it has been proposed that the control of such an AWD system is coordinated with the anti-lock brake control that periodically reduces the braking force according to the wheel lock during braking and restores the rotation of the wheels.

For example, Patent Document 1 describes an anti-lock brake in an engine-electric hybrid vehicle in which the front wheels are driven by an engine and the rear wheels are driven by a motor, in a state where the engine is stopped and the vehicle is driven by the motor drive of the rear wheels. It is stated that if control intervenes, the engine is restarted without waiting for a reacceleration request to obtain driving force from the AWD during reacceleration.
According to Patent Document 2, in an AWD automobile in which the driving force transmitted to the rear wheels can be adjusted by the fastening force of the coupling controlled by the solenoid valve, the antilock brake control is impaired when the antilock brake control is intervened. It is stated that torque is not transmitted to the rear wheels so that it does not occur.

Japanese Unexamined Patent Publication No. 2010-149682 Japanese Unexamined Patent Publication No. 2005-132300

In recent years, for the purpose of further improving the fuel efficiency of a vehicle, even if the vehicle is traveling at a high speed of, for example, 100 km / h or more, if a predetermined engine stop condition is satisfied, the engine is automatically stopped and the vehicle coasts. Is proposed to do.
In the case of such a vehicle in which the engine is not stopped during traveling, when the anti-lock brake control intervenes, the control to increase the output torque of the engine is performed for the purpose of recovering the rotation of the wheels at an early stage.
However, if sudden braking is performed with the engine stopped while driving and the wheels lock, the torque of the engine is not transmitted to the wheels, so it takes a relatively long time to recover the rotation of the wheels. In short, there is a concern that the steering stability of the vehicle during braking will decrease.
In view of the above-mentioned problems, an object of the present invention is to provide a vehicle control device having improved steering stability during braking from a state in which the engine is stopped during traveling.

The present invention solves the above-mentioned problems by the following solutions.
The invention according to claim 1 is an engine, a front wheel drive mechanism that transmits the output of the engine to the front wheels of a vehicle, a rear wheel drive mechanism that transmits the output of the engine to the rear wheels of the vehicle, and a front wheel drive mechanism. A vehicle control device provided in a vehicle including a binding force variable mechanism capable of changing the binding force between the rear wheel drive mechanism and the rear wheel drive mechanism, and a braking device for generating braking force on the front wheels and the rear wheels. An engine control device that automatically stops the engine when a predetermined engine stop condition is satisfied while the vehicle is running, and a predetermined sudden braking condition is satisfied while the vehicle is running and the engine is stopped. In this case, the vehicle control device is provided with a binding force control device that increases the binding force of the binding force variable mechanism.
According to this, when the binding force of the binding force variable mechanism is increased in response to the sudden braking performed while the engine is stopped, when one of the front wheels and the rear wheels is locked, the other wheel is locked. The driving force transmitted from the side enables early recovery from the wheel lock.
Further, even when the wheel lock does not occur, it is possible to prevent the wheel lock from occurring.

The vehicle control according to claim 1, wherein the engine control device restarts the engine when the sudden braking condition is satisfied while the engine is stopped. It is a device.
According to this, when a wheel lock occurs or there is a high risk of a wheel lock occurring, the engine is immediately restarted and the torque of the engine is transmitted to the wheels to recover from the wheel lock or the wheel lock. Can be prevented.

The invention according to claim 3 is the vehicle control device according to claim 2, wherein the binding force control device reduces the binding force of the binding force variable mechanism after the restart of the engine is completed. is there.
According to this, by reducing the binding force of the binding force variable mechanism after the restart of the engine is completed, the restraint between the front wheel drive mechanism and the rear wheel drive mechanism is weakened in a state where the engine restart is not completed. It is possible to prevent the vehicle from becoming unstable.

The vehicle control according to claim 2, wherein the binding force control device reduces the binding force of the binding force variable mechanism after the restart operation of the engine is started. It is a device.
According to this, when it is certain that the engine restart is performed in a short time, the fastening force variable mechanism is reduced by immediately reducing the fastening force of the fastening force variable mechanism in response to the start of the restart operation. Even if there is a time response delay in the decrease in the fastening force, it is possible to quickly return to the normal vehicle control in which the engine is operated and the fastening force of the variable fastening force mechanism is reduced.

The invention according to claim 5 is braking that performs anti-lock braking control that periodically reduces the braking force in response to the locking of at least one of the front wheels and the rear wheels by the braking force of the braking device or a sign thereof. The invention according to any one of claims 1 to 4, further comprising a control unit, wherein the binding force control device determines that the sudden braking condition is satisfied when the antilock brake control is executed. Vehicle control device.
According to this, the anti-lock braking device usually provided in a general vehicle is used, and a simple configuration that does not require the addition of new hardware is used, and the above-mentioned effect is appropriately described according to the wheel lock or its sign. Can be obtained.

The invention according to claim 6 includes a deceleration detection unit that detects the deceleration of the vehicle, and the binding force control device determines that the sudden braking condition is satisfied when the deceleration is equal to or greater than a predetermined threshold value. The vehicle control device according to any one of claims 1 to 4, wherein the vehicle control device is characterized by the above.
The invention according to claim 7 includes a braking force detecting unit that detects a parameter correlating with the braking force of the braking device, and the binding force control device is when the parameter correlating with the braking force is equal to or greater than a predetermined threshold value. The vehicle control device according to any one of claims 1 to 4, wherein it is determined that the sudden braking condition is satisfied.
According to this, even in a state where the wheels are not locked (a state in which the anti-lock brake control does not intervene), the binding force of the binding force variable mechanism is increased during sudden braking while the engine is stopped, and the front wheel drive mechanism and the rear wheels are increased. By increasing the binding force with the drive mechanism, it is possible to prevent wheel lock and ensure the stability of the vehicle.

According to a eighth aspect of the present invention, the front wheel drive mechanism has a function of directly connecting the engine and the front wheels after the engine is restarted, and the rear wheel drive mechanism has a variable binding force from the front wheel drive mechanism. The vehicle control device according to any one of claims 1 to 7, wherein a driving force is transmitted via a mechanism.
According to this, in the state after the restart of the engine is completed, by directly connecting the engine and the front wheels via the front wheel drive mechanism, the torque of the engine is transmitted to the front wheels where wheel lock is likely to occur, and the front wheels are locked. Can be recovered early or the front wheels can be prevented from locking.
Further, before restarting the engine, the driving force can be transmitted from the rear wheel side to the front wheel side by increasing the binding force of the binding force variable mechanism, and the effect of recovering and preventing the wheel lock of the front wheels can be obtained.

As described above, according to the present invention, it is possible to provide a vehicle control device having improved steering stability during braking from a state in which the engine is stopped during traveling.

It is a block diagram which shows typically the structure of the vehicle which has 1st Embodiment of the vehicle control device to which this invention is applied. It is a flowchart which shows the control when the vehicle control device of 1st Embodiment brakes from the running engine stop state. It is a flowchart which shows the control at the time of braking from the running engine stop state in the 2nd Embodiment of the vehicle control apparatus to which this invention was applied. It is a flowchart which shows the control at the time of braking from the running engine stop state in 3rd Embodiment of the vehicle control apparatus to which this invention was applied.

<First Embodiment>
Hereinafter, the first embodiment of the vehicle control device to which the present invention is applied will be described.
The vehicle control device of the first embodiment is provided in, for example, an automobile such as a four-wheeled passenger car having an AWD system for driving front wheels and rear wheels by an engine.
FIG. 1 is a block diagram schematically showing a configuration of a vehicle having the vehicle control device of the first embodiment.

As shown in FIG. 1, the vehicle 1 has a power train including an engine 10, a torque converter 20, a lockup clutch 30, a forward / backward switching unit 40, a variator 50, a front differential 60, a rear differential 70, a transfer clutch 80, and the like. ..

The engine 10 is an internal combustion engine used as a power source for traveling a vehicle.
As the engine 10, for example, a 4-stroke gasoline engine can be used.
The main body and auxiliary equipment of the engine 10 are controlled by the engine control unit 110, and an output torque corresponding to a required torque set based on an accelerator operation of a driver or the like is generated.

The torque converter 20 is a fluid coupling that transmits the output of the engine 10 to the forward / backward switching unit 40.
The torque converter 20 has a function as a starting device capable of transmitting engine torque from a stopped state of the vehicle.
The torque converter 20 has an impeller connected to the output shaft of the engine 10, a turbine connected to the input shaft of the forward / backward switching unit 40, a stator arranged between them, and the like.

The lockup clutch 30 is a clutch device provided in the torque converter 20 that can switch between a non-engaged state that allows a difference in rotational speed between the impeller and the turbine and an engaged state that restrains (directly connects) the impeller and the turbine. ..
The engagement and non-engagement of the lockup clutch 30 is controlled by the transmission control unit 120.

The forward / backward switching unit 40 is provided between the torque converter 20 and the variator 50, and has a forward mode in which the torque converter 20 and the variator 50 are directly connected and a backward mode in which the rotational output of the torque converter 20 is reversed and transmitted to the variator 50. The mode is switched according to a command from the transmission control unit 120.
The forward / backward switching unit 40 is configured to include, for example, a planetary gear set or the like.

The variator 50 is a speed change mechanism unit that continuously shifts the rotational output of the engine 10 transmitted from the forward / backward switching unit 40.
The variator 50 is, for example, a chain type continuously variable transmission (CVT) having a primary pulley 51, a secondary pulley 52, a chain 53, and the like.

The primary pulley 51 is provided on the input side (output side at the time of regenerative power generation) of the variator 50 when the vehicle is driven, and the rotational output of the engine 10 is input.
The secondary pulley 52 is provided on the output side (input side at the time of regenerative power generation) of the variator 50 when the vehicle is driven.
The secondary pulley 52 is rotatable around a rotation axis adjacent to the primary pulley 51 and parallel to the rotation axis of the primary pulley 51.
The chain 53 is formed in an annular shape and is wound around a primary pulley 51 and a secondary pulley 52, and power is transmitted between them.
The primary pulley 51 and the secondary pulley 52 each have a pair of sheaves that sandwich the chain 53, and the effective diameter is steplessly changed by changing the interval between the sheaves according to the shift control by the transmission control unit 120. It is possible.

The front differential 60 transmits the driving force transmitted from the variator 50 to the left and right front wheels.
The front differential 60 includes a final reduction gear and a differential mechanism that absorbs the difference in rotational speed between the left and right front wheels.
A drive shaft, which is a rotating shaft for transmitting driving force, is provided between the front differential 60 and the hubs of the left and right front wheels. The variator 50 and the front differential 60 are interlocked with each other via a gear shaft mechanism or the like. It is directly connected.
The gear shaft mechanism, front differential 60, drive shaft, and the like function as the front wheel drive mechanism according to the present invention.

The rear differential 70 transmits the driving force transmitted from the variator 50 via the transfer clutch 80, the propeller shaft (not shown), and the like to the left and right rear wheels.
The rear differential 70 includes a final reduction gear and a differential mechanism that absorbs the difference in rotational speed between the left and right rear wheels.
A drive shaft, which is a rotating shaft for transmitting driving force, is provided between the rear differential 70 and the hubs of the left and right rear wheels.
The propeller shaft, rear differential 70, drive shaft, and the like function as the rear wheel drive mechanism according to the present invention.

The transfer clutch 80 is provided in the middle of the rear wheel drive mechanism that transmits the driving force from the variator 50 to the rear differential 70, and connects or disconnects the power transmission path between them. The transfer clutch 80 functions as the binding force variable mechanism of the present invention.
The transfer clutch 80 is, for example, an electromagnetic wet multi-plate clutch capable of steplessly changing the fastening force (transmission torque capacity / binding force between the front wheel drive mechanism and the rear wheel drive mechanism) at the time of connection.
The fastening force (binding force) of the transfer clutch 80 is controlled by the transmission control unit 120.
The transfer clutch 80 can adjust the drive torque distribution of the front and rear wheels by changing the fastening force.

Further, the transfer clutch 80 reduces the fastening force when it is necessary to allow a difference in rotational speed between the front and rear wheels when the vehicle is turning, when anti-lock braking control, vehicle behavior control, etc. are executed during engine operation. The difference in rotation speed is absorbed by (opening) and slipping.
Further, the transfer clutch 80 temporarily engages the engine 10 until the engine 10 is restarted in order to prevent or recover the wheel lock during sudden braking from the state in which the engine 10 is stopped. Is controlled to increase.
This point will be described in detail later.

The vehicle 1 further includes an engine control unit 110, a transmission control unit 120, a behavior control unit 130, an environment recognition unit 140, and the like.
The engine control unit 110 comprehensively controls the engine 10 and its accessories.
The engine control unit 110 sets the driver required torque based on the operation amount of the accelerator pedal (not shown), and sets the engine 10 and its accessories so that the actual output torque of the engine 10 matches the driver required torque. Control.

Further, the engine control device 110 includes a running engine stop control function that automatically stops the engine 10 and coasts the vehicle 1 when a predetermined engine stop condition is satisfied while the vehicle 1 is running. There is.
Examples of the engine stop condition include the following.
(1) The driver required torque is 0 (the accelerator pedal is fully returned).
(2) The vehicle speed is within a predetermined range set in advance.
(3) The steering angle of the steering device is equal to or less than a predetermined threshold value.
(4) The acceleration in the left-right direction and the front-back direction acting on the vehicle body is equal to or less than a predetermined threshold value.
(5) The inter-vehicle distance to the preceding vehicle detected by the environment recognition unit 140 is equal to or greater than a predetermined threshold value.
The engine 10 is stopped, for example, by stopping fuel injection and ignition.
When the engine 10 is stopped while traveling, the transmission control unit 120 releases the lockup clutch 30 in order to allow the rotation speed of the output shaft of the engine 10 to decrease.
Further, when a part or all of these conditions are not satisfied, the engine control unit 110 immediately restarts fuel injection and ignition, and restarts the engine 10.

The transmission control unit 120 comprehensively controls the lockup clutch 30, the forward / backward switching unit 40, the variator 50, the transfer clutch 80, and the like.
The transmission control unit 120 controls the fastening force of the lockup clutch 30, the gear ratio of the variator 50, the fastening force (binding force) of the transfer clutch 80, and the like according to, for example, the driving condition of the vehicle such as the driver required torque and the vehicle speed. ..
The transmission control unit 120 functions as the binding force control device of the present invention.
Further, the transmission control unit 120 has a forward / backward switching unit 40 in a forward state (D range), a reverse state (R range), a neutral state (N range), and a parking lock state (P range) according to a travel range selection operation by the driver. Range) is switched.

The behavior control unit 130 is a braking control device that comprehensively controls the hydraulic service brake of the vehicle.
The behavior control unit 130 has a function of controlling the hydraulic unit 131.
The hydraulic unit 131 has a function of individually increasing or decreasing the brake fluid hydraulic pressure supplied from the master cylinder 132 for each wheel cylinder 133 of each wheel.
The master cylinder 132 is a pressurizing device that generates a master hydraulic pressure of brake fluid in response to a driver stepping on a brake pedal (not shown).
The master cylinder 132 is provided with a brake booster (vacuum booster) that utilizes the negative pressure of the intake pipe of the engine 10.

The hydraulic unit 131 includes a motor pump that pressurizes the brake fluid, and various solenoid valves (pressurizing valve, pressure reducing valve, holding valve, etc.) for individually controlling the hydraulic pressure of the wheel cylinder 133 of each wheel. ..
The behavior control unit 130 performs behavior control to generate a yaw moment in a direction of suppressing the behavior by generating a difference in braking force between the left and right wheels when, for example, behavior such as understeer or oversteer occurs.

Further, when the behavior control unit 130 detects a wheel lock or a sign thereof during braking based on the output of the vehicle speed sensor 134, the behavior control unit 130 periodically reduces the brake fluid hydraulic pressure of the wheel cylinder 133 of the wheel. Anti-lock brake control is performed to recover the rotation of the wheels.
In the present specification and claims, wheel locking means that the wheel rotation speed becomes extremely low or zero with respect to the running speed of the vehicle due to the braking of the wheels, and the tire tread slides (slip) with respect to the road surface. It shall indicate that it is in a state.
The vehicle speed sensor 134 is provided on a hub portion to which each wheel is attached, and generates a vehicle speed signal according to the rotation speed of the wheels.

The environment recognition unit 140 recognizes the environment in front of the own vehicle.
The environment recognition unit 140 is provided with, for example, a stereo camera 141, and can sequentially detect the presence or absence of another vehicle traveling in front of the own vehicle and, if the other vehicle exists, the relative position with respect to the own vehicle.
The stereo camera 141 performs known stereo image processing on the images captured by the pair of imaging devices (cameras) arranged so that the imaging range is directed toward the front of the vehicle and separated in the vehicle width direction, and the images captured by the left and right imaging devices, respectively. It has an image processing device.

Each of these units includes information processing means such as a CPU, storage means such as RAM and ROM, an input / output interface, and a bus connecting them.
Further, each of these units can communicate with each other via, for example, a CAN communication system which is a kind of in-vehicle LAN system, and can transmit necessary information.
Each of these units cooperates to form the vehicle control device of the first embodiment.

Hereinafter, the operation of the vehicle control device of the first embodiment will be described.
FIG. 2 is a flowchart showing control when braking from the running engine stopped state in the vehicle control device of the first embodiment.
Hereinafter, each step will be described step by step.

<Step S01: Judgment during running engine stop execution>
The engine control unit 110 determines whether or not the engine 10 is stopped while the vehicle 1 is running.
If the engine is stopped during running, the process proceeds to step S02, and in other cases, a series of processes is completed (returned).

<Step S02: ABS control intervention determination>
The behavior control unit 130 determines whether or not the above-mentioned antilock brake control is intervening (execution).
The behavior control unit 130 transmits an ABS control on signal to the engine control unit 110 and the transmission control unit 120 when the anti-lock brake control is intervening.
If the anti-lock brake control is intervening, the process proceeds to step S03 assuming that the sudden braking condition is satisfied, and in other cases, a series of processes is completed (returned).

<Step S03: Transfer clutch engaged>
The transmission control unit 120 increases the fastening force (binding force) of the transfer clutch 80 with respect to the fastening force used during normal traveling of the vehicle.
For example, the fastening force of the transfer clutch 80 can be set to the maximum practically usable fastening force.
After that, the process proceeds to step S04.

<Step S04: Fuel injection / cranking execution>
The engine control unit 110 restarts the engine 10.
The engine control unit 110 restarts fuel injection and ignition to the engine 10 and starts cranking for forcibly rotating the output shaft of the engine 10 from the outside.
The cranking may be performed, for example, by engaging the lockup clutch 30 and transmitting the driving force from the wheel side. Further, cranking may be performed using a starter motor (not shown).
After that, the process proceeds to step S05.

<Step S05: Engine complete explosion judgment>
The engine control unit 110 makes a complete explosion determination for determining whether or not the restart of the engine 10 is completed.
For example, when the rotation speed of the output shaft of the engine 10 exceeds a preset threshold value for a predetermined time or longer, the complete explosion determination can be established.
If the complete explosion determination is established, the process proceeds to step S06, and in other cases, step S05 is repeated.

<Step S06: Transfer clutch released>
The transmission control unit 120 reduces the fastening force (binding force) of the transfer clutch 80 from the increased state in step S03.
For example, the transmission control unit 120 can be in an released state in which the fastening force of the transfer clutch 80 is unavoidably equivalent to the friction generated.
After that, a series of processing is completed (returned).

According to the first embodiment described above, the following effects can be obtained.
(1) By increasing the fastening force of the transfer clutch 80 in response to sudden braking performed while the engine 10 is stopped, when one of the front wheels and the rear wheels is locked, from the other wheel side. The transmitted driving force enables early recovery from the wheel lock.
(2) When a wheel lock occurs, the engine 10 is immediately restarted and the torque of the engine 10 is transmitted to the wheels to recover from the wheel lock.
(3) The front wheel drive mechanism and the rear wheel drive mechanism are in a state where the restart of the engine 10 is not completed and the rotation is unstable by reducing the fastening force of the transfer clutch 80 after the restart of the engine 10 is completed. It is possible to prevent the vehicle 1 from becoming unstable due to the weakening of the restraint with the vehicle 1.
(4) By controlling the transfer force clutch 80 to increase the fastening force in response to the intervention of anti-lock brake control, the above-mentioned effects can be appropriately obtained by a simple configuration using devices and signals used in general vehicles. Obtainable.
(5) By directly connecting the engine 10 and the front wheels via the front wheel drive mechanism, the torque of the engine 10 is transmitted to the front wheels where wheel lock is likely to occur after the engine 10 is restarted, and the wheel lock of the front wheels is quickly restored. can do.
Further, before the restart of the engine 10 is completed, the driving force can be transmitted from the rear wheel side to the front wheel side by increasing the fastening force of the transfer clutch 80, and the recovery effect of the wheel lock of the front wheel can be obtained. it can.

<Second Embodiment>
Next, a second embodiment of the vehicle control device to which the present invention is applied will be described.
In each of the embodiments described below, the same reference numerals are given to the parts common to the previous embodiments, the description thereof will be omitted, and the differences will be mainly described.

FIG. 3 is a flowchart showing control when braking from the running engine stopped state in the vehicle control device of the second embodiment.
Hereinafter, each step will be described step by step.

<Step S11: Judgment during running engine stop execution>
The engine control unit 110 determines whether or not the engine 10 is stopped while the vehicle 1 is running.
If the engine is stopped during running, the process proceeds to step S12, and in other cases, a series of processes is completed (returned).

<Step S12: ABS control intervention judgment>
The behavior control unit 130 determines whether or not the above-mentioned antilock brake control is intervening (operating).
If the anti-lock brake control is intervening, the process proceeds to step S13 assuming that the sudden braking condition is satisfied, and in other cases, a series of processes is completed (returned).

<Step S13: Transfer clutch engaged>
The transmission control unit 120 increases the fastening force (binding force) of the transfer clutch 80 with respect to the fastening force used during normal traveling of the vehicle.
After that, the process proceeds to step S14.

<Step S14: Fuel injection / cranking execution>
The engine control unit 110 restarts fuel injection and ignition to the engine 10 and starts cranking for forcibly rotating the output shaft of the engine 10 from the outside.
After that, the process proceeds to step S15.

<Step S15: Transfer clutch released>
The transmission control unit 120 reduces the fastening force (binding force) of the transfer clutch 80 from the increased state in step S13.
After that, a series of processing is completed (returned).

According to the second embodiment described above, in addition to the same effect as the effect of the first embodiment described above (excluding those described in item (3)), the engine 10 is restarted in a short time. If it is certain, the fastening force of the transfer clutch 80 is immediately reduced in response to the start of the restart operation, so that the engine is delayed even when the fastening force of the transfer clutch 80 is reduced with a time response. It is possible to quickly return to the normal vehicle control in which the transfer clutch 80 is operated and the fastening force of the transfer clutch 80 is reduced.

<Third Embodiment>
Next, a third embodiment of the vehicle control device to which the present invention is applied will be described.
FIG. 4 is a flowchart showing control when braking from the running engine stopped state in the vehicle control device of the third embodiment.
Hereinafter, each step will be described step by step.

<Step S21: Judgment during running engine stop execution>
The engine control unit 110 determines whether or not the engine 10 is stopped while the vehicle 1 is running.
If the engine is stopped during traveling, the process proceeds to step S22, and in other cases, a series of processes is completed (returned).

<Step S22: Vehicle deceleration judgment>
The behavior control unit 130 calculates the deceleration of the vehicle 1 based on the transition of the traveling speed (vehicle speed) calculated based on the output of the vehicle speed sensor 134.
If the deceleration of the vehicle 1 is equal to or higher than a preset threshold value, the process proceeds to step S23 assuming that the sudden braking condition is satisfied, and in other cases, a series of processes is completed (returned).

<Step S23: Transfer clutch engaged>
The transmission control unit 120 increases the fastening force (binding force) of the transfer clutch 80 with respect to the fastening force used during normal traveling of the vehicle.
After that, the process proceeds to step S24.

<Step S24: Fuel injection / cranking execution>
The engine control unit 110 restarts fuel injection and ignition to the engine 10 and starts cranking for forcibly rotating the output shaft of the engine 10 from the outside.
After that, the process proceeds to step S25.

<Step S25: Engine complete explosion judgment>
The engine control unit 110 makes a complete explosion determination for determining whether or not the restart of the engine 10 is completed.
For example, when the rotation speed of the output shaft of the engine 10 exceeds a preset threshold value for a predetermined time or longer, the complete explosion determination can be established.
If the complete explosion determination is established, the process proceeds to step S26, and in other cases, step S25 is repeated.

<Step S26: Transfer clutch released>
The transmission control unit 120 reduces the fastening force (binding force) of the transfer clutch 80 from the increased state in step S23.
After that, a series of processing is completed (returned).

According to the third embodiment described above, in addition to the same effect as the effect of the first embodiment described above (excluding those described in item (4)), even in a state where the wheel lock is not reached By increasing the fastening force of the transfer clutch 80 during sudden braking while the engine 10 is stopped and increasing the binding force between the front wheel drive mechanism and the rear wheel drive mechanism, wheel lock is prevented and the stability of the vehicle 1 is improved. Can be secured.

(Modification example)
The present invention is not limited to the embodiments described above, and various modifications and modifications can be made, and these are also within the technical scope of the present invention.
(1) The configuration of the vehicle control device and the vehicle is not limited to each of the above-described embodiments, and can be appropriately changed.
For example, the functions realized by a plurality of units or the like in the vehicle control device of each embodiment may be integrated into a single unit or the like. On the other hand, the function realized by a single unit or the like in each embodiment may be divided into a plurality of units or the like.
Further, the type of engine and transmission is not particularly limited.
(2) The vehicle AWD system of each embodiment has an FWD-based configuration in which the engine is directly connected to the front wheel drive mechanism and the rear wheel drive mechanism is driven from the front wheel drive mechanism via a variable fastening force mechanism (transfer clutch). However, the configuration of the AWD system is not limited to this, and can be changed as appropriate.
For example, the rear wheel drive mechanism may be directly connected to the engine, and the front wheel drive mechanism may be driven from the rear wheel drive mechanism via the fastening force variable mechanism in an RWD-based configuration.
Further, in a full-time AWD system having a mechanical center differential such as a bevel gear type or a planetary gear type in order to absorb the difference in rotational speed between the front wheel drive mechanism and the rear wheel drive mechanism, the front wheel side output unit and the rear wheel side of the center differential It may have an electromagnetic type or hydraulic type clutch that restrains the difference in rotation speed from the output unit.
(3) In each embodiment, the vehicle uses only the engine as a power source for traveling as an example, but the present invention is not limited to this, and the outputs of the engine and the electric motor can be transmitted to the wheels, respectively. It can also be applied to possible engine-electric hybrid vehicles.
(4) In the first and second embodiments, it is assumed that the sudden braking condition is satisfied when the anti-lock brake control intervenes while the engine is stopped, and in the third embodiment, the vehicle deceleration is the threshold value. In the above cases, the fastening force of the transfer clutch 80 is increased assuming that the sudden braking condition is satisfied, but the present invention is not limited to this, and the sudden braking condition may be determined by another method.
For example, a parameter that correlates with the braking force of the braking device may be detected, and when this parameter becomes equal to or higher than a predetermined threshold value, it may be determined that the sudden braking condition is satisfied.
As parameters that correlate with the braking force, for example, the wheel cylinder hydraulic pressure of the brake fluid, the master cylinder hydraulic pressure, the depression amount (stroke) of the brake pedal, the pedaling force, and the like can be used.
Further, the method for detecting the deceleration of the vehicle is not limited to the one using the output of the vehicle speed sensor, and other methods such as using the front-rear acceleration sensor of the vehicle body may be used.

1 Vehicle 10 Engine 20 Torque converter 30 Lock-up clutch 40 Forward / backward switching part 50 Variator 51 Primary pulley 52 Secondary pulley 53 Chain 60 Front differential 70 Rear differential 80 Transfer clutch 110 Engine control unit 120 Transmission control unit 130 Behavior control unit 131 Hydraulic Unit 132 Master Cylinder 133 Wheel Cylinder 134 Vehicle Speed Sensor 140 Environment Recognition Unit 141 Stereo Camera

Claims (8)

With the engine
A front-wheel drive mechanism that transmits the output of the engine to the front wheels of the vehicle,
A rear wheel drive mechanism that transmits the output of the engine to the rear wheels of the vehicle,
A variable binding force mechanism capable of changing the binding force between the front wheel drive mechanism and the rear wheel drive mechanism,
A vehicle control device provided in a vehicle provided with a braking device for generating braking force on the front wheels and the rear wheels.
An engine control device that automatically stops the engine when a predetermined engine stop condition is satisfied while the vehicle is running.
The vehicle is provided with a binding force control device that increases the binding force of the binding force variable mechanism when a predetermined sudden braking condition is satisfied while the vehicle is running and the engine is stopped. Control device. The vehicle control device according to claim 1, wherein the engine control device restarts the engine when the sudden braking condition is satisfied while the engine is stopped. The vehicle control device according to claim 2, wherein the binding force control device reduces the binding force of the binding force variable mechanism after the restart of the engine is completed. The vehicle control device according to claim 2, wherein the binding force control device reduces the binding force of the binding force variable mechanism after the restart operation of the engine is started. A braking control unit that performs anti-lock braking control that periodically reduces the braking force in response to at least one lock of the front wheel and the rear wheel due to the braking force of the braking device or a sign thereof is provided.
The vehicle control device according to any one of claims 1 to 4, wherein the binding force control device determines that the sudden braking condition is satisfied when the antilock brake control is executed. Equipped with a deceleration detector that detects the deceleration of the vehicle
The one according to any one of claims 1 to 4, wherein the binding force control device determines that the sudden braking condition is satisfied when the deceleration is equal to or higher than a predetermined threshold value. Vehicle control device. A braking force detecting unit for detecting a parameter correlating with the braking force of the braking device is provided.
Any one of claims 1 to 4, wherein the binding force control device determines that the sudden braking condition is satisfied when the parameter correlating with the braking force is equal to or greater than a predetermined threshold value. The vehicle control device according to the section. The front wheel drive mechanism has a function of directly connecting the engine and the front wheels after the engine is restarted.
The vehicle control device according to any one of claims 1 to 7, wherein the rear wheel drive mechanism transmits a driving force from the front wheel drive mechanism via the binding force variable mechanism. ..

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