JPH0231931A - Torque allocation control device for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To improve the travelling performance at the time of turning by detecting the counter steering operation of a driver to the generation of the side slip during the turning and reducing the torque allocation of rear wheels. CONSTITUTION:In the ordinary way, the torque allocation of front wheels B, B and rear wheels C, C are variably controlled by a torque allocation changing means D, corresponding to the operated condition. On the other hand, at the time of turning, when the side slip of the rear wheels C, C is generated, a driver performs the counter steering operation for operating a handle to the opposite side of the turning direction so as to eliminate it. At this stage, a torque allocation control means F, receiving a signal from a counter steering detecting means E, actuates the torque allocation changing means D so as to reduce the torque allocation of the rear wheels C, C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a torque distribution control device that variably controls torque distribution between front and rear wheels in a four-wheel drive vehicle.

(Conventional technology) All wheels on the front, rear, left and right sides are driven by the engine output 4
In wheel drive vehicles, it is desirable not to always maintain the torque distribution of each wheel in an equal state, but to variably control the torque distribution to the optimal distribution according to the driving condition at that time. , it has been shown that driving performance during cornering can be improved by variably controlling the torque distribution between the front and rear wheels in accordance with the lateral acceleration acting on the vehicle.

(Problem to be Solved by the Invention) By the way, in the vehicle that variably controls the torque distribution between the front and rear wheels during turning as described above, when the torque distribution on the rear wheel side is increased in order to particularly improve turning performance, When the friction coefficient of the road surface is small, so-called tank slip, in which the rear wheels slip outward in the turning direction, tends to occur. In other words, the tire's lateral slip limit with respect to the road surface decreases as the drive torque of the wheel increases, and therefore, when the torque distribution to the rear wheels is increased as described above, this lateral slip becomes more likely to occur. In this way, when turning, the front
Even in a four-wheel drive vehicle in which torque distribution to the rear wheels is variably controlled, there is still room for improvement in terms of improving driving performance during turns.

Therefore, an object of the present invention is to further improve the running stability of this type of four-wheel drive vehicle during turning by quickly eliminating the rear wheel skidding when it occurs as described above. shall be.

<Means for Solving the Problems> In order to solve the above problems, the following means are used in the present invention. .

That is, as shown in FIG. 1, the torque distribution changing means is configured to drive the front wheels B, B and rear wheel C1C by the output of the engine A, and changes the torque distribution of each wheel according to the driving condition. In a four-wheel drive vehicle equipped with a countersteer state, the countersteer detection means E detects the countersteer state of the steering wheel, and when the countersteer state is detected by the detection means E, the rear wheel C1C is controlled by the torque distribution change means. and torque distribution control means F for reducing the torque distribution on the side.

<Function> According to the above configuration, the torque distribution between the front wheels B, B and the rear wheels C1C is normally variably controlled by the torque distribution changing means according to the driving condition, for example, in order to improve the controllability when turning. , control is performed to increase the torque distribution on the rear wheel C1C side. On the other hand, when turning, the rear wheel C1C
When a sideslip occurs, the driver attempts to resolve this by performing a countersteering operation by operating the steering wheel in the opposite direction to the turning direction. At this time, upon receiving a signal from the countersteering detection means E, The torque distribution control means F operates the torque distribution changing means so as to reduce the torque distribution to the rear wheels C2C. As a result, the steering characteristics are modified in the direction of understeer, improving the straight-line performance of the vehicle.
The side slip of the rear wheel C1C is quickly resolved.

(Example) Examples of the present invention will be described below.

First, the overall configuration of this embodiment will be explained with reference to FIG.
The vehicle 1 according to the present embodiment is a four-wheel drive vehicle in which left and right front wheels 2.3 and left and right rear wheels 4, 5 are both driven wheels, and the output of an engine 6 is transmitted through a transmission 7. The signal is input to the transfer device 8 and divided into the front wheels 2 and 3 side and the rear wheels 4 and 5 side. The output to the front wheels 2 and 3 is provided by a first propeller shaft 9 extending forward from the side of the transfer device 8, and a front wheel differential device 10.
and the left and right front wheels 2 via the left and right front wheel drive shafts 11 and 12.
.
5.16 to the left and right rear wheels 4.5.

Further, the left and right front wheel drive shafts 11.12 and the left and right rear wheel drive shafts 15.16 have disc rotors that rotate integrally therewith, and that brake the rotation of the disc rotors when braking pressure is supplied. Brake device 1 consisting of a caliper etc.
7, 18, 19.20 are provided respectively. These brake devices 17 to 20 are operated by the braking pressure generated in the mask cylinder when the brake pedal is depressed, while the braking operation is also controlled by a separately provided brake controller 21 via a braking pressure control valve to be described later. It is now possible to do so.

Furthermore, this vehicle 1 is equipped with an actuator 23 that opens and closes a throttle valve 22 provided in the intake passage of the engine 6, and an engine controller 24 that controls the operation of this actuator 23. According to the signal from the accelerator opening sensor 25 inputted to the throttle valve 24
The opening degree of 2 is controlled according to the accelerator opening degree.

A torque distribution controller 26 is provided which controls torque distribution to each of the wheels 2 to 5 by performing brake control and engine output control via the brake controller 21 and engine controller 24. 26, a signal from the accelerator opening sensor 25, a signal from each wheel speed sensor 27...27 that detects the rotation speed of each wheel 2 to 5, and a rudder for torque distribution control during turning. A signal from the angle sensor 28, a signal from the lateral acceleration sensor 29 that detects the lateral acceleration acting on the vehicle, and various sensors (not shown), such as the throttle control for controlling the throttle opening and feedback for the brake control. Signals from sensors and brake pressure sensors are input.

The torque distribution controller 26 operates the brake devices 17 to 20 of the wheels 2 to 5 through the brake controller 21 to reduce the drive torque of the corresponding wheel by the amount of the braking torque, and also reduces the drive torque of the corresponding wheel by the amount of the braking torque. The above engine controller 2
By controlling the engine output through the wheel 4, the torque distribution is variably controlled while maintaining the total driving force of each wheel 2 to 5, depending on the driving state.

Next, with reference to FIG. 3, the structure of the brake pressure control valve and its actuator for operating each of the brake devices 17 to 20 by the brake controller 21 will be explained. In addition, Figure 3 shows the brake equipment 17.1 for the left and right front wheels 2.3.
8 is shown, the brake devices 19 and 20 for the left and right rear wheels 4 and 5 are similarly configured.

From the mask cylinder 30 to the left and right front wheel brake devices 17
．． A brake pressure control valve 33.34 is installed on each brake pressure passage 31.32 that supplies brake pressure to the left and right rear wheel brake devices 19, 18 (and left and right rear wheel brake devices 19, 20),
Also provided are actuators 35, 36 that actuate these control valves 33, 34, respectively.

Both of the brake pressure control valves 33 and 34 are connected to the cylinder 3.
The pistons 33b and 34b are inserted into the cylinders 33a and 34a, and the variable volume chamber 33 is formed inside these cylinders 33a and 34a.
c, 34c and control room 33d.

34d and the piston 33b.

34b is connected to the variable volume chamber 3 by springs 33e and 34e.
The configuration is such that the volumes of 3c and 34c are biased in the direction of increasing. Braking pressure passages 31.32 from the mask cylinder 30 to the brake devices 17, 18 (and 19.20) of each wheel pass through the variable volume chambers 33c, 34c, respectively, and normally the pressure generated in the mask cylinder 30 is The braking pressure is supplied to each of the brake equipment W17-20 through these variable volume chambers 33c, 34c.

In addition, a control chamber 33d is provided in the pistons 33b and 34b.
, 34d, the piston 33b
, 34b move in a direction that reduces the volume of the variable volume chambers 33c, 34c against the springs 33e, 34e, the check valves 33f, 34f close the braking pressure inlets to the variable volume chambers 33c, 34c. It is provided.

When control pressure is introduced into the control chambers 33d, 34d and the brake pressure passages 31.32 are shut off by the check valves 33f, 34f, the piston 33b,
34b, braking pressure is generated within the variable volume chambers 33c, 34c, and this braking pressure is applied to each brake device 17 to 20.
are supplied to each.

On the other hand, actuators 35 and 36 that operate these braking pressure control valves 33 and 34 are actuated by pressure increasing solenoid valves 3 and 36, respectively.
5a, 36a, and pressure reducing solenoid valves 35b, 36b. The pressure increase solenoid valves 35a and 36a are arranged on control pressure supply lines 39 and 40 that extend from the oil pump 37 via the relief valve 38 to the control chambers 33d and 34d of the brake pressure control valves 33 and 34, respectively, and The pressure reducing solenoid valves 35b and 36b are arranged on drain lines 41 and 42 led from the control chambers 33d and 34d, respectively. And these solenoid valves 35a, 36a, 3
5b and 36b are controlled to open and close by the brake control signal from the brake controller 21, and the pressure increasing solenoid valve 35
a, 36a open and the pressure reducing solenoid valves 35b, 36b close, the control chamber 33d of the braking pressure control valve 33.34,
By introducing the control pressure to 34d, braking pressure is supplied to each brake device 17 to 20, and the pressure increasing solenoid valves 35a and 36a are closed and the pressure reducing solenoid valves 35b and 36b are closed.
When the control chambers 33d and 34d are opened, the control pressure is discharged from the control chambers 33d and 34d, thereby reducing the braking pressure supplied to each of the brake devices 17-20. By adjusting the braking pressure supplied to the wheels, the braking torque applied to each of the wheels 2 to 5 is controlled.

Next, the operation of this embodiment will be explained with reference to FIG. 4 and subsequent drawings showing the torque distribution control operation by the torque distribution controller 26.

First, the overall control operation will be explained with reference to the flowchart in FIG. 4. At the start of operation, the system is initialized in step S1, and then in step S28, when a predetermined measurement timing has come, the system is initialized as shown in FIG. Based on the signals from the sensors 25, 27, . . . 27, 28, and 29, the amount of operation or momentum such as the accelerator opening, each wheel speed, the steering angle, and the lateral acceleration is measured. Then, steps S4 to S
6, torque distribution control according to the turning state, torque distribution control according to the longitudinal and lateral acceleration of the vehicle, and torque distribution control according to the wheel slip state are executed, and in step S7, these are executed. Brake control and engine output control are performed to achieve the torque distribution obtained through control.

Next, the specific contents of each control in steps 84 to S7 will be explained. First, torque distribution control according to the turning state is performed according to the flowchart in FIG. 5.

In this control, it is first determined in step Sll whether the vehicle speed is equal to or higher than a set value, and when the vehicle speed is relatively high than the set value, then the value of the first flag F1 is determined in step S12. This flag F1 indicates On when the steering wheel operation is a normal operation, but becomes "1" when a counter steer state is detected. Note that the vehicle speed is detected based on a signal from a wheel speed sensor 27 shown in FIG.

Assuming that the vehicle is not currently in the countersteering state, since F1=0, step S13 is executed next to determine the value of the 27th lag F2, which is set according to each stage of turning. This flag F2 indicates “
0"', "1" when entering a corner (early stage of turning), °'2" during cornering (mid-turning), and 3°' when exiting a corner (end of turning). state, and F,=O, so next step S+4
It is determined whether the steering angle is greater than or equal to a set value. and,
If the steering angle is smaller than the set value, further step S+5 is performed.
It is determined whether the rate of change of the steering angle is greater than or equal to the set value, and if this rate of change is also smaller than the set value, it is determined that the straight-ahead state continues, and control for straight-ahead travel is executed in step SI6. do.

On the other hand, when the vehicle enters a corner and the steering angle becomes more than the set value, or the rate of change of the steering angle becomes more than the set value, the second flag F2 is set to "1" in step SI7, and step The rear wheel torque distribution ratio R is set in accordance with StS to S20 as follows.

That is, first, as shown in FIG. 6, the basic distribution ratio R8 corresponding to the steering angle is read from a preset map, and the correction amount of the distribution ratio R according to the rate of change of the steering angle is read from the map shown in FIG. Read ΔR and set RO+ΔR as the rear wheel distribution ratio R.

In this case, the basic distribution ratio RO is set to increase as the steering angle increases from 0.5 to a predetermined value smaller than 1 in a predetermined steering angle range, as shown in FIG. Further, as shown in FIG. 7, the correction amount ΔR is set to increase as the steering angle change rate increases in a range from 0 to a predetermined value.

Therefore, when entering a corner, the larger the steering angle and the larger its rate of change, the larger the rear wheel torque distribution ratio will be set to a value greater than 0.5.

When the corner is entered in this way, the second flag F2 becomes "1", so next step S22 is executed from step S13 to step S21, and it is determined whether the steering angle is increasing or not. , if it is increasing, continue the control at the beginning of the turn in steps Szg to S20 above,
Further, when the increase in the steering angle stops and the transition to the middle stage of turning occurs, step 323. In S24, the 27th lug F2 is set to 2n, and the torque distribution ratio R is set to 0.5, that is, the torque distribution to the front and rear wheels is set to be equal.

Furthermore, if the 27th lag F2 becomes "2", then steps S25 to S26 are executed to determine whether or not the steering angle has started to decrease, and it is determined that the turning angle is still in the middle stage until the steering angle begins to decrease. Then, in step S24, the rear wheel torque distribution ratio R is maintained at 0.5. When the steering angle starts to decrease, the rate of change (rate of decrease) is determined in step S27.
Determine whether or not is less than or equal to the set value. In this case, when returning the steering wheel when exiting a corner from a normal turning state, the operation is performed relatively gracefully and the rate of change of the steering angle is below the set value, so the next step is step 32g. After setting the second flag F2 to "3'' in step 32
The torque distribution at the end of the turn is set according to steps 9 to S31.

To set the torque distribution at the end of the turn, read the basic distribution ratio R8' of the rear wheels according to the steering angle from the map shown in FIG.
The rear wheel torque distribution ratio R is determined by subtracting from this basic distribution ratio R8' a correction amount ΔR' corresponding to the rate of change in the steering angle read from the map shown in FIG. In this case, the basic distribution ratio Ro' is reduced from 0.5 to a predetermined value smaller than 0.5 as the steering angle decreases, that is, as the steering wheel returns. , and the correction amount ΔR' to be subtracted from this basic distribution ratio Ro' is set to be a larger value as the rate of change of the steering angle is larger. Therefore, at the end of the turn, as the steering wheel is returned and the return speed is faster, the rear wheel torque distribution ratio R is set to a value smaller than 0.5.

Thereafter, when the steering angle decreases to below the set value, steps S32 to S33. Run SS4,
The second flag F2 is reset to "0" and the rear wheel torque distribution ratio R is set to 0.5, thereby ending the torque distribution control during this turn.

In this way, in a normal cornering state, the torque distribution ratio R of the rear wheels is made larger than 0.5 at the beginning of the corner, and the steering characteristics tend to be one-bar steer, thereby achieving good controllability. Further, at the end of a turn, the torque distribution ratio R of the rear wheels is made smaller than 0.5, and the steering characteristics tend to understeer, thereby improving the stability of the vehicle.

On the other hand, if rear wheel skidding occurs during a turn, and the driver performs a countersteering operation to counteract this by operating the steering wheel in the opposite direction to the turning direction, the driver can quickly resolve the rear wheel skidding. The control is performed as follows.

In other words, when it is determined in step S26 that the steering angle has decreased, and then in step S27 it is determined whether the rate of change is less than or equal to the set value, when the steering angle is decreased due to the canter steer operation in response to side slip of the rear wheels, the normal steering wheel Since the rate of change in the steering angle becomes significantly larger than the operation to return the steering angle, it is determined that the rate of change in the steering angle is greater than the set value. Therefore, at the time of countersteering, steps S27 to S835 to S are executed, the first flag F1 is set to the value "1" indicating the countersteering state, and the second flag F1 indicating the turning stage is set. After setting the flag F2 to "3", the rear wheel torque distribution ratio R is set to a predetermined value Rcs smaller than 0.5.

Then, by setting the first flag F1 to "1", the steps from step S12 to step 83g+83
9 to determine the steering angle and its rate of change, and if the steering angle is greater than the set value or the rate of change is greater than the set value, it is determined that the countersteer state is still in place, and step S40 is performed. The torque distribution ratio R of the rear wheels is maintained at a predetermined value RC5 smaller than 0.5.

In this way, when a countersteer operation is performed in response to side slipping of the rear wheels, the torque distribution between the front and rear wheels is set such that the front wheels become larger, and the steering characteristics are accordingly corrected in the direction of understeer. As a result, the straight-line performance of the vehicle is improved, and the lateral drift of the rear wheels as described above is quickly eliminated.

If it is determined in steps 338+339 that the steering angle has become less than the set value and that the rate of change has also become less than the set value, it is determined that the countersteering state has ended, and step S41. In S42, reset the 17th lug F to "0" and set the rear wheel torque distribution ratio R to 0.
．． 5, and the control for this rear wheel side slip ends. Furthermore, if the vehicle speed becomes lower than the set value, the side slip of the rear wheels will be resolved naturally, so step S43 is executed from step Sll to reset the 17th lug F1 to "0'°, and similarly control for side slip is performed. end.

In addition, in this embodiment, as shown in FIG. 4, torque distribution control according to acceleration and torque distribution control for wheel slip are performed in parallel with the above-mentioned torque distribution control during turning. Next, these controls will be explained.

First, to explain torque distribution control according to acceleration, this control is performed according to the flowchart shown in FIG. The value at the time (VMIN) N and the value at the previous measurement (VIII
IN) The acceleration G in the longitudinal direction is determined as the difference from s-t, and in step S52, the torque distribution ratio Q of the rear wheels is determined according to this acceleration G.

is read from the map shown in FIG. Also, step S
At st, the torque distribution ratio of the right wheel (total distribution ratio of the front and rear wheels on the right side) according to the lateral acceleration G2 is determined as the first
Read from the map in Figure 2.

In that case, as shown in FIG. 11, the torque distribution ratio Qz of the rear wheels according to the longitudinal acceleration G1 is set to increase as the acceleration 01 increases within a predetermined value or more. The drive torque of the front and rear wheels changes in response to the load shift to the rear wheels due to acceleration, and the drive torque effectively increases the propulsion force of the vehicle without causing slip in both the front and rear wheels. will be converted to .

Furthermore, as shown in FIG. 12, the torque distribution ratio Q2 for the right wheel is set to a larger value as the lateral acceleration in the right direction increases, and is set to a smaller value as the lateral acceleration in the left direction increases. ing. In other words, with respect to acceleration in the lateral direction, the torque distribution ratio of the wheel on the side where the load increases is increased in accordance with the load movement.

Furthermore, the control of torque distribution according to the slip condition is
First, in step S61, the slip ratio of the front wheel to the rear wheel is S1, the slip ratio of the rear wheel to the front wheel is S2, the slip ratio of the right wheel to the left wheel is S3, and the slip ratio of the left wheel to the right wheel is determined. S
4 are calculated according to the following formulas.

S + = (VFL + VFR) / (VRL +
V RR) S2 = (VFIL+VRFI) / (
VFL+VFR)Ss=(VpR+VRR)/(Vp
t10VRL)S, = (VFL+VRL) / (Vpa
+VRR) Here, V PL, V FR+ V RL
, V RIL, it's left front wheel, right front wheel, left rear wheel,
Each wheel speed of the right rear wheel is shown.

Next, in step S62, it is determined whether or not the slip ratio Sl of the front wheels relative to the rear wheels is greater than 1. When Sl>1, that is, when the front wheels are slipping, step S6
At step S, the rear wheel torque distribution ratio P1 is read from the map shown in FIG. Read the ratio Pl. In that case, as shown in Fig. 14, when the front wheel is slipping, Sl〉1
) is set so that the torque distribution ratio P1 of the rear wheels becomes larger than 0.5 as the slip ratio S1 increases in the range of 80 or more, and as shown in FIG. When the vehicle is slipping (S2>1), the slip ratio 82 of the rear wheels relative to the front wheels is a predetermined value S. The rear wheel torque distribution ratio P1 is set to become smaller than 0.5 as the torque increases within the above range. In other words, when either the front or rear wheels are slipping, the distribution for the one that is slipping is reduced, and the distribution for the one that is not slipping is increased.

Similarly, it is determined in step S65 whether the slip ratio S3 of the right wheel relative to the left wheel is greater than 1, and when S3>1, that is, when the right wheel is slipping, the map shown in FIG. Torque distribution ratio P of the right wheel from
2 is read, and when S3<1, that is, when the left wheel is slipping, the torque distribution ratio P2 of the right wheel is read from the map shown in FIG. 17 in step S67. In that case, as shown in Figure 16, if the right wheel is slipping (
S3>1), the torque distribution ratio P2 of the right wheel becomes 0 as the slip ratio 83 increases in the range of 88 or more.
．． 5, and as shown in Fig. 17, when the left wheel is slipping (S4>1)
In this case, the slip ratio 84 of the left wheel with respect to the right wheel is a predetermined value S.
. Torque distribution P of the right wheel according to the increase in the above range
2 is set to be greater than 0.5.

In other words, in this case as well, the distribution is set to be smaller for the left and right wheels that are slipping, and larger for the wheels that are not slipping.

As described above, the torque distribution ratio R of the rear wheels according to the turning state is the torque distribution ratio Q of the rear wheels according to the acceleration in the longitudinal direction.
! , Torque distribution ratio Q2 of the right wheel according to the lateral acceleration
, and the torque distribution ratio P1. of the rear wheel and right wheel according to the slip rate of the wheels. Once P2 is set, these distribution ratios are summed to obtain a total torque distribution ratio for each wheel, and engine control and brake control are performed to achieve this distribution ratio.

Next, this engine and brake control will be explained according to the flowchart of FIG. 18.

First, in this control, in step S71, a torque corresponding to the accelerator opening degree, that is, a required torque T requested by the driver is determined. is calculated, and then in step S72, L is calculated as the total torque distribution ratio of the rear wheel and right wheel, which is the sum of the torque distribution ratios set according to each of the driving conditions described above, according to the following formula.

K=R+Q1+Pt I L=Q2+P2-0゜5 Here, each torque distribution ratio R, Q+, Q2, PtP2
are all values based on 0.5, and since it is necessary to use 0.5 as the reference for the total distribution ratio, as mentioned above, L is 1 from the value of the sum of each torque distribution ratio. Or 0.5 will be subtracted.

Next, in steps 373 to S79, the output torque Ts required to achieve the total torque distribution ratio as described above, with L as a target, is calculated. That is, in step 873, it is determined whether the total distribution ratio K of the rear wheels is greater than 0.5, and when K>0.5, the process proceeds to step S74.
If K≦0, 5, then (IK) is replaced with X in step S75. In other words, the larger value of the total distribution ratio of the rear wheels and the total distribution ratio of the front wheels (1-K) is set as X.

Similarly, in step S76, it is determined whether the total distribution ratio of the right wheel is greater than 0.5, and when L>0.5, the value is replaced with Y in step S77, and if L≦0. 5, set (1-L) to Y in step 87g.

Then, in step S79, the output torque TS required to realize the target torque distribution is calculated according to the following equation.

Ts=4-X-Y-T(.

When the required torque Ts is calculated in this way, a control signal is output to the actuator 23 of the throttle valve 22 shown in FIG. 2 to obtain the required torque Ts in step SSO, and the engine output is control.

Furthermore, in step S8□, the braking torque 'r'' is applied to each of the front, rear, left and right wheels based on the torque distribution ratio L.
b pL, T b PR, T b RL, and T b RE are calculated according to the following formulas.

]'bpL=Ts/4 (I K) (I L
) T.

Tb1R=Ts/4 (IK)LT.

TbRt, = Ts/4 K(L L)T.

Tb1R=Ts/4 KLT.

Then, in step S82, a control signal is output to the actuator of the brake control valve shown in FIG. 3 to control the brake devices 17 to 20 so that these braking torques are obtained.

Furthermore, due to the above braking torque, the driving torque of each wheel is: TFL = (I K) (L L> T.

TFR= (I K ) LTO TRL= K (L L, ) TOTRR=KLT
O, and the total torque is the required torque T.

, and the torque distribution ratio between the front and rear wheels is [(1-K
):K), the torque distribution ratio between the left and right wheels is ((1-L)
):L).

(Effects of the Invention) As described above, according to the present invention, the front
In a four-wheel drive vehicle with variable control of rear wheel torque distribution, when rear wheel skidding occurs during a turn,
Detecting the driver's countersteering operation in response to this,
By reducing the torque distribution to the rear wheels, when such skidding occurs, the steering characteristics are corrected in the direction of understeer, improving the straight-line performance of the vehicle, and therefore, this rear wheel skidding is quickly resolved. will be done.

This further improves the running stability of this type of four-wheel drive vehicle.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic configuration diagram of the present invention, and FIG.
Figure 8 shows an embodiment of the present invention, Figure 2 is a control system diagram, Figure 3 is a circuit diagram showing the configuration and arrangement of the brake pressure control valve and its actuator, and Figure 4 is the overall torque distribution control. A flowchart diagram showing the operation, FIG. 5 is a flowchart diagram showing torque distribution control according to the turning state, and FIGS.
Figure 9 is an explanatory diagram of each map used in this control, and Figure 10 is an explanatory diagram of each map used in this control.
The figure is a flowchart diagram showing torque distribution control according to acceleration, Figures 11 and 12 are explanatory diagrams of maps used in this control, Figure 13 is a flowchart diagram showing torque distribution control according to slip conditions, and Figures 14 to 12 are flowchart diagrams showing torque distribution control according to slip conditions. FIG. 17 is an explanatory diagram of a map used in this control, and FIG. 18 is a flowchart diagram showing engine and brake control. 2-5...Wheels, 6...Engine, 21.24...
- Torque distribution changing means (brake controller, engine controller), 26... Torque distribution control means (torque distribution controller), 28... Counter steer detection means (steering angle sensor).

Claims (1)

[Claims] (1) A torque distribution control device for a four-wheel drive vehicle that is configured to drive front wheels and rear wheels using engine output and is equipped with a torque distribution changing means that changes the torque distribution of each wheel depending on the driving condition. countersteer detection means for detecting a countersteer state of the steering wheel; and torque distribution control means for reducing the torque distribution on the rear wheel side by the torque distribution changing means when the countersteer state is detected by the detection means. A torque distribution control device for a four-wheel drive vehicle, characterized in that it is equipped with the following.