JPH0295961A - Car slippage control device - Google Patents

Abstract

PURPOSE:To avoid excessive thermal load by increasing the target slip ratio as the thermal load on a braking means increases within a specified range, and interrupting the brake control substantially when the thermal load exceeds specified value. CONSTITUTION:When a slip sensing means senses a slip exceeding a certain level, a drive torque control means allows a braking means to perform braking motion so that the slip ratio or the amount of slip is identical with No.1 target value preset by a target value setting means, and also permits an output adjusting means to make adjusting motion so that the same is identical with No.2 target value. The target value setting means increases No.1 target value as the thermal load by a thermal load sensing means enlarges within No.1 specified range, and decreases No.2 target value as the sensed thermal load enlarges within No.2 specified range when the slip sensing means has sensed a slip over specified level. This avoids the thermal load from becoming excessive.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slip control device for an automobile that performs control to suppress the slip of drive wheels on a road surface in an automobile.

(Prior Art) When the wheels of a vehicle slip on a large scale on the road surface when the vehicle is running, grip running is not performed and appropriate running characteristics cannot be obtained. 2. Description of the Related Art Slip control devices are known that perform control to suppress slips of drive wheels on a road surface by activating a brake device included in an automobile or reducing engine output.

In such a slip control device, when a slip of the driving wheels with respect to the road surface is detected to be more than a predetermined value, for example, a target slip rate is set as a control target, and the slip control device sets a target slip rate that is a control target, and increases the slip rate by a predetermined amount or more to the set target slip rate. The drive torque acting on the specific drive wheel is reduced by controlling the brake system to operate and reducing the engine output in order to match the slip rate of the specific drive wheel where slip has been detected. It is done like this.

In such a slip control device, the brake device is always activated when the detected slip is more than a predetermined value, so the brake device is not put into a state where it is overused. The heat load on the brake system becomes excessive.

In order to deal with such inconvenience, for example, Japanese Patent Laid-Open No. 63-34
No. 270 discloses that when a slip of a predetermined value or more is detected and the thermal load on the brake device becomes a predetermined value or more, the target slip rate set in the control for operating the brake device is increased. A slip control device is disclosed that is designed to avoid overusing the brake system.

(Problem to be Solved by the Invention) However, in such a slip control device, even if the target slip rate set in the control for operating the brake device is increased, the target slip rate set in the control for changing the engine output is increased. Since the target slip ratio is maintained constant, the reduction rate of the drive torque acting on the drive wheels in slip control increases the target slip ratio set in the control for operating the brake device. It increases compared to before and then becomes smaller, which poses a technical problem in continuously performing appropriate slip control.

In view of this, the present invention provides a control and/or an engine control system that operates a braking means to apply braking force to the wheel where the slip is detected when a slip of the drive wheel with respect to the road surface is detected to be more than a predetermined value. Provided is a slip control device for an automobile that is capable of avoiding excessive thermal load on the braking means when performing control to reduce output, and is capable of continuously performing appropriate slip control. The purpose is to provide.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a slip control device for an automobile according to the present invention has the following basic configuration as shown in FIG.
Slip detection means for detecting the slip of the driving wheels of an automobile with respect to the road surface; braking means for performing a braking operation to individually apply braking force to the driving wheels; and output for performing an adjustment operation to change the output of the engine installed in the automobile. When a slip of a predetermined value or more is detected by the adjusting means, the thermal load detecting means for detecting the thermal load on the braking means, and the slip detecting means, the slip rate or slip amount for the specific drive wheel where the slip was detected. an operation of causing a brake means to perform a braking operation to apply braking force to a specific drive wheel in which slip has been detected, and/or a specific drive wheel in which slip has been detected, in order to match the first target value set in advance. In order to match the slip rate or slip amount of the wheels with a second target value set in advance, the drive torque control means causes the output adjustment means to perform an adjustment operation, and the target value setting means is provided. The value setting means increases the first target value as the heat load detected by the heat load detection means increases within a first predetermined range when a slip of a predetermined value or more is detected by the slip detection means. At the same time, the second target value is made smaller as the detected heat load becomes larger within a second predetermined range.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 conceptually shows an example of a slip control device for an automobile according to the present invention, together with a four-wheel drive vehicle to which it is applied.

An engine 12 is mounted at the front of a vehicle body 10 in the four-wheel drive automobile shown in FIG. The engine 12 has, for example, four cylinders 11, each of which is supplied with fuel from a fuel supply system through an intake passage 16 provided with a throttle valve 14 that is driven to open and close by a throttle actuator 13. A mixture formed by fuel and intake air is supplied. Each cylinder 11
The air-fuel mixture supplied thereto is combusted by the operation of the ignition system and is discharged to the exhaust passage 17. The combustion of the mixture causes the engine 12 to rotate, and the generated torque is transmitted to the transmission 22. Center differential mechanism 23. A propeller shaft 24 and a differential mechanism 25 for the front wheels, and a propeller shaft 26 for the rear wheels.
and the differential mechanism 27, the front left wheel 20L and the front right wheel 20R are
, are transmitted to the left rear wheel 21L and right rear wheel 21R, respectively.

A brake control section 30 is provided in association with the front left wheel 20L, the front right wheel 20R, the rear left wheel 21L, and the rear right wheel 21R. The brake control unit 30 controls the left front wheel 20
L, front right wheel 20R9, rear left wheel 21L, and rear right wheel 21H have disc brakes 35A to 35D each including a disc 32 attached to each, and a caliper 34 provided with a brake pad that presses the disc 32. . Caliper 34 in each of disc brakes 35A to 35D
is equipped with a wheel cylinder 36, and each wheel cylinder 36 is connected to a conduit 37a to 37d extending from a hydraulic pressure adjustment section 40, respectively. Each caliper 34
When brake fluid pressure is supplied to the wheel cylinder 36 from the fluid pressure adjustment section 40 via the conduits 37a to 37d,
The brake pad is pressed against the disc 32 with a pressing force corresponding to the supplied brake fluid pressure, and the left front wheel 20 is
L, right front wheel 20R2, left rear wheel 21L, and right rear wheel 21R are braked.

The hydraulic pressure adjustment unit 40 is supplied with hydraulic pressure in response to a depression operation of the brake pedal 41 from a power cylinder 43 provided in association with the brake pedal 41 through conduits 42a and 42b, and also supplied to the hydraulic pressure adjusting unit 40 through a pump 44 and a pressure regulating valve 45. The hydraulic pressure generated by the hydraulic pressure is supplied through conduit 46. During normal braking in which no slip control is performed, the hydraulic pressure adjustment unit 40 operates to form a brake hydraulic pressure according to the depression operation of the brake pedal 41 and supply it to the disc brakes 35A to 35D through the conduits 37a to 37d. During slip control, the built-in electromagnetic on-off valve 5
Disc brake 35A~ according to the operating status of 1~58
The brake fluid pressure for the disc brakes 35D is individually formed and the brake fluid pressures are selectively supplied to the disc brakes 35A to 35D, respectively.

The electromagnetic on-off valves 51 to 5 are electromagnetic on-off valves 51 and 52, electromagnetic on-off valves 53 and 54. The disc brakes 35A to 35A are combined with the electromagnetic on-off valves 55 and 56 and the electromagnetic on-off valves 57 and 58, and each set is provided with the front left wheel 20L, the front right wheel 20R, the rear left wheel 21L, and the rear right wheel 21R. 35
It is said to be involved in adjusting the brake fluid pressure with respect to D. One of the electromagnetic on-off valves 51, 53, 55 and 57 of each set is opened, and the other electromagnetic on-off valves 52, 54.
56 and 5 are in the closed state, the brake fluid pressure supplied to the disc brakes 35A to 35D is increased, and conversely, one of the electromagnetic on-off valves 51, 53, 55 of each set is increased. and 57 are closed, and the other electromagnetic on-off valves 52, 54, 56, and 58 are opened, the brake fluid pressure supplied to the disc brakes 35A to 35D is reduced, and each set of brake fluid pressure is reduced. When the disc brakes 35A to 35D are closed, the brake fluid pressure supplied to the disc brakes 35A to 35D is maintained at the current state.

In addition to the above configuration, a control unit 100 is provided for controlling the opening and closing of the electromagnetic on-off valves 51 to 58 and controlling the operation of the throttle actuator 13. The control unit 100 includes speed sensors 61 to 64 provided in connection with the left front wheel 20L, right front wheel 20R9, left rear wheel 21L, and right rear wheel 21R, respectively. 21L and right rear wheel 21
Detection signals S<b>1 to S<b>4 corresponding to the respective circumferential speeds of R, detection signals St corresponding to the throttle opening obtained from the throttle opening sensor 65 provided in relation to the throttle valve 14 , and the accelerator pedal 66 . Accelerator pedal 66 obtained from a related accelerator opening sensor 67
A detection signal Sa corresponding to the amount of depression of the steering wheel 68 and a detection signal Sd corresponding to the steering angles of the front left wheel 2OL and the front right wheel 2OR obtained from a steering angle sensor 69 provided in relation to the steering wheel 68 are supplied. Along with disc brake 3
Temperature sensors 71 provided in relation to 5A to 35D, respectively
Disc brakes 35A to 35D obtained from ~74
Detection signals SL, -SL, corresponding to the respective temperatures are supplied.

The control unit 100 outputs detection signals S+ to S4.
is captured at a predetermined period, and the captured detection signal S,
-S, the estimated vehicle speed value and the same speed value are calculated based on the circumferential speed values of the left front wheel 20L, right front wheel 20R1, left rear wheel 21L, and right rear wheel 21H, and the left front wheel 20L, right front wheel 20R1 It is determined whether a slip of a predetermined value or more has occurred in each of the left rear wheel 21L and the right rear wheel 21H by comparing the calculated value of each training speed with a predetermined value Aa. . And front left wheel 20L, front right wheel 20R
1 Among the left rear wheel 21L and the right rear wheel 21R, those whose uniform speed is determined to be equal to or higher than the value Aa are treated as having a slip of a predetermined value or more, and slip control is performed, and the left front wheel 20L and the right rear wheel 21R are Front wheel 20R9 Left rear wheel 21L and right rear wheel 21R
If it is determined that the value of each training speed is less than the value Aa, normal throttle opening control is performed.

In addition, when normal throttle opening control is performed by the control unit 100, the normal target throttle opening is set according to the amount of depression of the accelerator pedal 66, which is detected by the detection signal Sa, and the detection signal St is set by the detected throttle. The normal target throttle opening and the throttle valve 1 are adjusted so that the opening of the valve 14 is brought close to the normal target throttle opening.
A throttle valve drive signal Ct corresponding to the difference between the opening degree and the opening degree of No. 4 is generated and supplied to the throttle actuator 13. As a result, the throttle valve 14 is driven to open and close by the throttle actuator 13, and its opening degree is controlled to match the normal target throttle opening degree. Note that the normal target throttle opening is the accelerator pedal 6.
As the amount of depression 6 increases, it increases in a predetermined proportional relationship.

When the control unit 100 performs slip control, the same speed values for the left front wheel 20L, the right front wheel 20R, the left rear wheel 21L, and the right rear wheel 21R are used to prevent slips on the road surface of more than a predetermined value. It is detected which of the four wheels the wheel that has occurred (hereinafter referred to as a slipping wheel) is, and the number of slipping wheels is detected, and furthermore, the number of detected slipping wheels is plural. In this case, the number of slipping wheels among a plurality of slipping wheels at almost the same time is detected, and based on the detection results, the estimated vehicle speed used in setting the target slip rate is calculated and the slip control mode is set. It will be done.

In setting the estimated vehicle speed by the control unit 100, the detection signals S1 to S4 taken in one cycle before are calculated based on the circumferential speeds of the left front wheel 20L, right front wheel 20R, left rear wheel 21L, and right rear wheel 21R. During high-speed driving, the estimated vehicle speed value Vn-1 (where n is a positive integer) is greater than or equal to a predetermined value vh, and the calculated estimated vehicle speed value 7-1 is less than the value vh. , and during low-speed straight running when the steering angles of the left front wheel 2OL and the right front wheel 2OR are less than the predetermined value 08 when the detection signal Sd is detected, the left front wheel 20L,
A predetermined correction coefficient α is applied to the lowest circumferential speed value of the right front wheel 20R, the left rear wheel 21L, and the right rear wheel 21R. (ku1
) to calculate the estimated vehicle speed value Vn at that time. Further, if the estimated vehicle speed value VFI-1 is less than the value vh,
During low-speed turning when the steering angles of the front left wheel 2OL and the front right wheel 2OR are 08 or more, wheels that do not slip more than a predetermined amount on the road surface (hereinafter referred to as non-slip wheels) are selected according to the detected slip wheels and their number. Based on the circumferential speed of the slip wheel (called slip wheel), under different settings
Estimated vehicle speed is set.

When setting the estimated vehicle speed during low-speed turning, the left turning state of the vehicle is detected based on the steering angles of the front left wheel 2OL and the front right wheel 20R when zero or one slipping wheel is detected. When the front left wheel 20L and the rear right wheel 21R are non-slip wheels,
The estimated vehicle speed value Vn is calculated by multiplying the average value of the circumferential speed of the left front wheel 2OL and the circumferential speed of the right rear wheel 21R by a predetermined correction coefficient α1. When a left turn of the vehicle is detected when one of the wheels is detected to be a slipping wheel, the circumferential speed of the right front wheel 20R and the circumferential speed of the left rear wheel 2LL, which are non-slip wheels. The estimated vehicle speed value Vn is calculated by multiplying the average value by the correction coefficient α1.On the other hand, when zero or one slipping wheel is detected, the right turning state of the vehicle is detected. When the front right wheel 2OR and the rear left wheel 21L are non-slip wheels, the average value of the circumferential speed of the right front wheel 20R and the circumferential speed of the left rear wheel 21L is multiplied by a correction coefficient α1 to obtain the estimated vehicle speed. The value Vn of the right front wheel 20R and the left rear wheel 21L is calculated.
When it is detected that at least one of the wheels is a slipping wheel and a right turn of the automobile is detected, the circumferential speed of the left front wheel 2OL and the right rear wheel 21R, which are non-slip wheels, is The estimated vehicle speed value Vn is calculated by multiplying the average value by the correction coefficient α.

Furthermore, when two slip wheels are detected, the non-slip wheels are the left front wheel 2OL and the right front wheel 2O.
R1, or in the case of the left rear wheel 2LL and right rear wheel 21R, the average value of the circumferential speed of the left front wheel 2OL and the circumferential speed of the right front wheel 2OR, or the circumferential speed of the left rear wheel 21L and the right rear wheel 21R. A predetermined correction coefficient α is calculated based on the average value of the circumferential speed of
The estimated vehicle speed value Vn is calculated by multiplying by 2. In addition, when the non-slip wheels are the front left wheel 20L and the rear left wheel 21L, or the front right wheel 20R and the rear right wheel 21R, the wheel that takes the trajectory closest to the trajectory of the center of gravity of the vehicle among the non-slip wheels. The estimated vehicle speed value Vn is calculated by multiplying the circumferential speed by the correction coefficient α2. Specifically, when the non-slip wheels are the left front wheel 2OL and the left rear wheel 21L, when the vehicle is turning right, the left front wheel 2OL
The circumferential speed of the left rear wheel 21L is multiplied by a correction coefficient α2, and when the vehicle is turning left, the circumferential speed of the left rear wheel 21L is multiplied by a correction coefficient α2.
On the other hand, when the non-slip wheels are the right front wheel 2OR and the right rear wheel, if the car is turning right, the circumferential speed of the right front wheel 2OR is multiplied by the correction coefficient α2, and the car is turning left. If the vehicle is in the rotating state, the circumferential speed of the right rear wheel 21R is multiplied by the correction coefficient α2 to calculate the estimated vehicle speed value Vn in each case.

On the other hand, the non-slip wheels are the left front wheel 2OL and the right rear wheel 21R.
1 or, in the case of the right front wheel 2OR and the left rear wheel 2IL, the average value of the circumferential speed of the left front wheel 20L and the circumferential speed of the right rear wheel 21H, or the circumferential speed of the right front wheel 20R and the left rear wheel 21.
The average value with the peripheral speed of L is multiplied by the correction coefficient α2,
An estimated vehicle speed value Vn is calculated.

When three slip wheels are detected,
The estimated vehicle speed value Vn is calculated by multiplying the circumferential speed of the remaining non-slip wheel by the correction coefficient α.

When it is detected that all of the front left wheel 20L, the front right wheel 20R, the rear left wheel 21L, and the rear right wheel 21R are slip wheels, the estimated vehicle speed value ■n calculated just before the slip wheels are detected is , the estimated vehicle speed value Vn at that time
It is said that

Note that the above-mentioned correction coefficient α8. Considering the fact that as the number of slip wheels increases, the car will be placed in an unstable state, it is desirable that α2 and α be set as follows: 1>α, α2>α .

In this way, the estimated vehicle speed is set according to which of the four wheels the slipping wheel is and the number of slipping wheels. The speed is set to a value that does not deviate significantly from the actual vehicle speed, taking into account the actual driving conditions of the vehicle, using a relatively simple configuration.

While the estimated vehicle speed is set as described above, the control unit 100 performs slip control on the slip rough wheels based on a combination of the number of slip wheels and two or more of the four wheels of the vehicle. The following is performed according to a predetermined control mode.

In the slip control by the control unit 100, the brake control unit 30 controls the left front wheel 20L, the right front wheel 2, and the like depending on the number of slip wheels and the combination of two or more of the four wheels of the vehicle.
0R9 Brake control that applies braking force to each of the left rear wheel 21L and right rear wheel 21R, and throttle control that reduces the engine output by reducing the opening degree of the throttle valve 14 are selectively performed. be made to be

When performing such brake control and throttle control, a predetermined value TC;1. Tc2 and T
C3 (however, O < TG 1 < TG 2 < TC3) and the set slip rate TGTR1 and the value TGI that are uniformly set for each wheel.
, TG2 and TC3, and the set slip knob ratio TGBR which is uniformly set for each wheel is used, and the target slip ratio TBR in brake control is calculated using the formula 1TBR. = (TGT
R-TGBR)Xx+TGBR, and
The target slip rate TTR in throttle control is expressed by the formula;
TTR=(TC;TR−TGBR)Xy+TGBR is set.

In the above equation, X is a correction coefficient, and as shown in FIG. When the temperature TB takes a value equal to or higher than the set value Tc, it is assumed to take a value of 1, and the set value T
When taking a value between c and a lower value Tb, it increases between zero and 1 as the value of temperature TB increases,
When the value is less than or equal to the value Tb, it is assumed to be zero, and y is also a correction coefficient, and as shown in FIG.
When the temperature TB' of the highest temperature among those corresponding to the slipping wheels among ~35D takes a value lower than the set value Ta, take ■, and the temperature TB' is set between the set value Ta and a higher value Tb. When taking a value between
As the value of B' increases, it decreases between 1 and zero, and when the temperature TB' takes a value greater than or equal to the value Tb, it is assumed to take a value of zero.

Further, when performing brake control and throttle control, the estimated vehicle speed value Vn calculated as described above is used to control the left front wheel 20L.

Actual slip rates SFL and SFR of the right front wheel 20R1, the left rear wheel 21L, and the right rear wheel 21R, respectively.

SRL and SRR are each expressed by the formula 1sFL=(VFLn-
Vn)/VFLn, 5FR= (VFRnVn)/V
FRn, 5RL= (VRLn-Vn)/VRL
n, and 5RR= (VRRn-Vn)/V
Calculated by RRn (VFLn, VFRn, VRL
n and VRRn (where n is a positive integer) are the front left wheel 20L, the front right wheel 20R1, the rear left wheel 21L, and the rear right wheel 21, respectively.
value of circumferential velocity for R).

In brake control, the actual slip rate SFL calculated by the control unit 100,
Based on a comparison between each of SFR, SRL, and SRR and the target slip ratio TBR set therefor, a drive signal Ca-Ch is selectively formed, and it is determined whether the electromagnetic switching valve corresponds to provided to those who do. As a result, the brake fluid pressure supplied to the disc brakes 35A-35D corresponding to the slipping wheel is adjusted, and the slip rate of the slipping wheel is adjusted, that is, among the actual slip rates SFL, SFR, SRL and SRR. One or more of the slip ratios are controlled to match the target slip ratio TBR set for the slip ratio TBR.

In addition, in throttle control, the control unit 100 determines the actual slip rates SFL, SFR, S
An average value SAv of RL and SRR is calculated, and a throttle valve drive signal Ct is formed based on a comparison between the calculated average value SAV and a set target slip ratio TTR.
It is supplied to the throttle actuator 13. As a result, the opening degree of the throttle valve 14 is adjusted, and the slip rate of the slipping wheel, that is, the actual slip rate SFL, is adjusted.
Each of one or more of SFR, SRL, and SRR is the target slip rate TTR set for it.
However, when performing such throttle control, the opening degree of the throttle valve 14 is set to be larger than the normal target throttle opening degree, which is set according to the amount of depression of the accelerator pedal 66. Sometimes, such throttle control is stopped and normal throttle control is started.

As mentioned above, the target slip rates TBR and TTR in brake control and throttle control are set using correction coefficients X and y, so that in brake control, target slip rate TBR and temperature TB are set. When taking a value between the values Tb and Tc, the value is set to increase as the temperature TB increases, and the temperature TB is set to a value that increases as the temperature TB increases.
When taking a value greater than c, it is set to the maximum value, so
When the temperature TB takes a value equal to or higher than the value Tc, brake control is substantially not performed. On the other hand, in throttle control, the target slip ratio TTR takes the maximum value when the temperature TB' takes a value below the value Ta, and decreases as the temperature TB' takes a value larger than the value Ta. When the temperature TB° takes a value larger than the value Tb, it is assumed to be the minimum value, so the temperature TB' becomes the value Tb.
When a larger value is taken, only throttle control with a reduced target slip ratio TTR is performed.

By doing this, the disc brake 35
Control for suppressing the slip of the slipping wheel on the road surface is continuously and appropriately performed while avoiding an excessive thermal load on the one corresponding to the slipping wheel among A to 35D.

As mentioned above, brake control and throttle control are selectively performed depending on the number of slipping wheels and the combination of slipping wheels, but when it is detected that there is only one slipping wheel, only brake control is performed. It will be done. Also,
When two slip wheels are detected,
The control is performed according to one of predetermined control modes corresponding to each of six combinations of two of the four wheels. That is, when the left rear wheel 21L and the right rear wheel 21R are slip wheels, only brake control is performed, and when the left front wheel 2OL and the right front wheel 2OR are slip wheels, the left rear wheel 21L and the right rear wheel are Since the influence on the running stability of the vehicle is likely to be greater than when the wheel 21R is a slipping wheel, in addition to brake control, the target slip rate TTR is set and the slip rate TGTR is set to take the value TG3. If throttle control is performed under the condition that In addition to brake control, throttle control is performed with the target slip rate TTR set such that the set slip rate TGTR takes the value TG2, and the slip wheels are the left front wheel 2OL and the right rear wheel 21R1, or the right front wheel. 20R and left rear wheel 21L, only brake control is performed.

In this way, when two slip wheels are detected, the slip control mode is set according to the combination of those slip wheels, so that the influence on the driving stability of the vehicle is relatively small. When this is the case, only brake control is performed, so the engine output is not reduced and the wheel drive torque is not reduced more than necessary. In addition, when the impact on the driving stability of the vehicle is likely to be large, throttle control is performed in addition to brake control. A situation where movement occurs is effectively avoided.

On the other hand, there are three slip wheels detected, and
If they become slip wheels at approximately the same time, 1. Since the driving condition of the car is extremely unstable, the target slip rate TTR is equal to the set slip rate TGTR.
Only throttle control is performed under the condition that TG2 is set to take the value TG2. In addition, if the three slip wheels do not become slip wheels at approximately the same time, in addition to brake control, the target slip rate TTR is set so that the set slip rate TGTR takes the value TG2. Throttle control is performed.

Furthermore, when it is detected that there are four slipping wheels, the brake control is stopped, the target slip rate TTR is set to zero, and throttle control is performed to fully close the throttle valve 14.

Then, with the throttle valve 14 fully closed,
In order to judge whether each of the four wheels is in a state where there is substantially no slip, the circumferential velocity average value VAV is calculated using the formula;
VAV= (VFLn+VFRn+VRLn+VRR
n)/4, the calculated circumferential speed average value VA
V is used, and the total deviation value ε is calculated using the formula; e= (VFL
n-VAV)” + (VFRn-VAV)” + (V
RLn-VAV)" + (VRRn-VAV)", and the calculated total deviation value ε is a predetermined value (1!
It is determined whether or not it is less than or equal to Za. If it is determined that the total deviation value ε is larger than the value Za, the four wheels are not in a slip-free state, so the throttle valve 14 is maintained in a fully closed state, and the total deviation value ε is If it is determined that the value is less than or equal to the value Za, it is assumed that the four wheels are in a substantially non-slip state, and the slip control is restarted.

When slip control is restarted, the total deviation value ε
Brake control is not performed until a predetermined period Tx has elapsed from the time when T becomes equal to or less than the value Za, and the target slip rate T
Throttle control is performed only when TR is set such that the set slip rate TGTR takes the value TGI. However, the target slip rate TTR is the set slip rate TG.
When throttle control is performed with TR set to take the value TGI, the throttle valve 14
When the opening degree is larger than the normal target throttle opening degree set according to the amount of depression of the accelerator pedal 66,
Such throttle control is stopped and normal throttle opening control is started.

In this way, when it is detected that all four wheels are slipping more than a predetermined amount on the road surface, the brake control is stopped until the four wheels are substantially free from slipping. By maintaining the throttle valve 14 in a fully closed state and quickly reducing the engine output, 1. A situation that affects the running stability of the vehicle is avoided, and the four wheels are quickly reduced. is brought into a state where there is virtually no slippage. Therefore, even if the four wheels slip more than a predetermined amount with respect to the road surface, a driving state in which the estimated vehicle speed and the actual vehicle speed are equal or substantially equal can be obtained in a very short time. Also,
After the four wheels have been made substantially slip-free,
Until the period Tx has elapsed, there is a high possibility that the four wheels will again experience more than a predetermined amount of slip on the road surface, but as mentioned above, during this period only throttle control is performed and the predetermined Since the occurrence of the above-mentioned slip is suppressed, the running stability of the automobile is ensured immediately after the four wheels are brought into a state where there is substantially no slip.

The slip control as described above is mainly performed based on the operation of a microcomputer built into the control unit 100. For an example of a program executed by such a microcomputer, see the flowcharts in FIGS. 5 to 12. and explain.

In the main program shown in the flowchart of FIG. 5, after starting, initial settings are performed in process 101, and detection signals 3 and 3 are set in process 102. -34
．． A process is performed to import St, Sa, and Sd to create necessary data, and in the following process from 103 to 10 days, a program for slip determination, a program for setting estimated vehicle speed, a program for setting control mode, and a program for brake heat load correction are sequentially created. The program, throttle control program, and brake control program are executed and the process returns to process 102.

As shown in the flowchart of FIG. 6, the slip determination program executed in process 103 in the flowchart of FIG.
In step 112, the simultaneous slip count flag SFS is set to zero, and in process 112, the value VFL of the circumferential speed of the left front wheel 2OL one cycle before is set as the value ■WO, and the circumferential speed of the left front wheel 2OL at that time is The value VFLn is the circumferential velocity value vW
At the same time, the slip wheel determination flag SFQ is set to the left front wheel slip flag 5FFL, and in process 113, a slip detection program as shown in FIG. 7 is executed.

In the slip detection program shown in FIG. 7, after starting, in process 131, the circumferential velocity value vWO is subtracted from the circumferential velocity value VWN to calculate the same-month velocity Δ■W of the left front wheel 2OL, and the subsequent decision In step 132, it is determined whether or not the monthly speed Δ■W is equal to or greater than the value Aa, and if it is determined that the same-monthly velocity Δ■W is equal to or greater than the value Aa, a slip of a predetermined value or more has occurred in the left front wheel 2OL. In step 133, the slip wheel determination flag SFQ is set to 1, and 1 is added to the simultaneous slip count flag SFS to set a new simultaneous slip count flag SFS, and this program is terminated. If it is determined that the monthly speed Δ■W is less than the value Aa, the program is terminated without going through process 133. After the program shown in FIG. 7 is finished, the left front wheel slip flag 5 is
FFL is replaced with the slip wheel determination flag SFQ and the process proceeds to process 115.

In process 115, the value VFR,, of the circumferential speed of the right front wheel 2OR one cycle before is set as the value VWO, and the value VFRn of the circumferential speed of the right front wheel 2OR at that time is set as the value VWN, and the slip wheel judgment is performed. After setting the flag SFQ as the right front wheel slip flag 5FFR and executing a slip detection program as shown in FIG. 7 in process 116, in process 117 the right front wheel slip flag 5FFR is replaced with the slip wheel determination flag SFQ. Proceed to process 118. In process 118, the value VRL of the circumferential speed of the left rear wheel 21L one cycle before is set as the value VWO, the value VRLn of the circumferential speed of the left rear wheel 21L at that time is set as the value VWN, and the slip After setting the wheel determination flag SFQ to the left rear wheel slip flag 5FRL and executing a slip detection program as shown in FIG. 7 in process 119, process 12
1, the left rear wheel slip flag 5FRL is replaced with a slip wheel determination flag SFQ, and the process proceeds to process 122. In the process 122, the right rear wheel 21 of one cycle before
Value of peripheral speed of R VRRn-.

is set as the value ■WO, and the value VRRn of the circumferential speed of the right rear wheel 21R at that time is set as the value VWN, and the slip wheel determination flag SFQ is set as the right rear wheel slip flag 5FRR.
After executing a slip detection program as shown in FIG. 7 in process 123, in process 124, the right rear wheel slip flag 5FRR is replaced with a slip wheel determination flag SFQ, and process 125
Proceed to.

In process 125, the left front wheel slip flag S
F F L, right front wheel slip flag 5FFR.

A slip wheel count flag SF is set by adding the left rear wheel slip flag 5FRL and the right rear wheel slip flag 5FRR, and in the subsequent decision 126, it is determined whether or not the accelerator pedal 66 is in the released state, and the accelerator pedal is If it is determined that the accelerator pedal 66 is in the released state, the program is terminated after the slip wheel count flag SF is set to zero in process 127, and in decision 126, the accelerator pedal 66 is set in the released state. If it is determined that the program has not been executed, the program is terminated without going through process 127.

On the other hand, process 104 in the flowchart of FIG.
As shown in the flowchart of FIG. 8, after the program for setting the estimated vehicle speed is started, in process 140, the program for setting the estimated vehicle speed that is executed one cycle before is set.
. -3 is greater than or equal to the value vh, and if it is determined that the estimated vehicle speed value Vfi-, is greater than or equal to the value ■h, in process 141, the estimated vehicle speed value Vn is determined by the detection signal S1 ~S4 is rainy left front wheel 20L, right front wheel 20R9
A correction coefficient α is applied to the smallest of the circumferential velocity values VFLn, VFRn, VRLn, and RRn for the left rear wheel 21L and right rear wheel 21R, respectively. If it is determined in decision 140 that the estimated vehicle speed value vll-1 is less than the value vh, then in decision 142 the detection signal Sd is It is determined whether the steering angle θ of the front wheel 2OL and the right front wheel 2OR is greater than or equal to the value 68, and the steering angle θ is determined to be the value 8.
If it is determined that the steering angle θ is less than
If it is determined that the value is greater than or equal to 68, the process advances to decision 143.

In decision 143, it is determined whether the slip wheel count flag SF is zero or 1, and if it is determined that the slip wheel count flag SF is zero or l, in decision 144, the steering angle θ is Based on this, it is determined whether or not the vehicle is turning to the right. If it is determined that the vehicle is turning to the right, in decision 145, it is determined whether or not the front right wheel slip flag 5FFR is zero. Judgment, right front wheel slip flag 5FFR
is determined to be zero, decision 146
In step 147, it is determined whether or not the left rear wheel slip flag 5FRL is zero, and if it is determined that the left rear wheel slip flag 5FRL is zero, in process 147, the estimated vehicle speed value Vn is calculated by formula; = ((VFRn+VRL
n)/2)
In step 48, the estimated vehicle speed value Vn is calculated using the formula: % formula %, and the program ends.

On the other hand, if it is determined in decision 144 that the vehicle is not turning to the right, then in decision 151 it is determined whether or not the front left wheel slip flag 5FFL is zero, and the front left wheel slip flag 5FFL is determined to be zero. If it is determined that the right rear wheel slip flag 5FRR is zero, it is determined in decision 152 whether or not the right rear wheel slip flag 5FRR is zero. Estimated vehicle speed value Vn
Formula: Vn= ((VFLn+VRRn)/2)×α1
If it is determined in decisions 151 and 152 that the left front wheel slip flag 5FFL and the right rear wheel slip flag 5FRR are not zero, in process 154, the estimated vehicle speed value Vn The formula; Vn= ((VFRn+VRLn
)/2)×α, and terminate this program.

Further, if it is determined in decision 143 that the slip wheel count flag SF is not zero or l, then in decision 155 it is determined whether the slip wheel count flag SF is 2 or not, and the slip wheel count flag SF is 2, in decision 156, it is determined whether or not the right front wheel slip flag 5FFR is zero, and the right front wheel slip flag 5FFR is set to zero.
is not zero, decision 157
In , it is determined whether or not the right rear wheel slip flag 5FRR is in a state of ambience, and if it is determined that the right rear wheel slip flag 5FRR is not zero, the decisigon 158 determines whether the vehicle is in a right-turning state. Decide whether or not. If it is determined that the vehicle is in a right-turning state, then in process 159, the estimated vehicle speed value Vn is calculated using the formula; Vn=VFLnXα2, and the program is terminated. Further, if it is determined in decision 158 that the vehicle is not in a right-turning state, in process 160, the estimated vehicle speed transplantation Vn is calculated using the formula: Vn=V
This program is completed after calculating by RLnXα2.

On the other hand, if it is determined in decision 157 that the right rear wheel slip flag 5FRR is zero, then in decision 161 the left front wheel slip flag 5FFL is determined to be zero.
is zero, and set the left front wheel slip flag 5F.
If FL is determined to be zero, process 162
, the estimated vehicle speed value Vn is expressed as; Vn= ((VF
Ln+VRRn)/2)xα2, this program is terminated, and if it is determined in decision 161 that the left front wheel slip flag 5FFL is not zero, in process 163, the estimated vehicle speed value Vn is calculated by the formula;
Vn=((VRRn+VRLn)/2)×α2 is calculated, and this program ends.

In addition, if it is determined in decision 156 that the front right wheel slip flag 5FFR is zero, then in decision 170, the front left wheel slip flag 5FFR is determined to be zero.
is zero, and set the left front wheel slip flag 5F.
If FL is determined to be zero, process 164
, the estimated vehicle speed value Vn is expressed as; Vn= ((VFR
n+VFLn)/2)xα2, this program is ended, and if it is determined in decision 170 that the left front wheel slip flag 5FFL is not zero, then in decision 165, the left rear wheel slip flag 5FRL is zero. Determine whether or not. If it is determined that the left rear wheel slip flag 5FRL is zero, then in process 166, the estimated vehicle speed value Vn is calculated using the formula;
Vn=((VF Rn +V Rj,n)/2
) X cr z and terminate this program. On the other hand, if it is determined in decision 165 that the left rear wheel slip flag 5FRL is not zero,
In decision 167, it is determined whether the vehicle is in a right-turning state, and if it is determined that the vehicle is not in a right-turning state, in process 168, the estimated vehicle speed value Vn is calculated using the formula; = VRRn
After calculating Vn=VFRnXα2, this program ends.

Furthermore, if it is determined in decision 155 that the slip wheel count flag SF is not 2, then in decision 171 it is determined whether or not the slip wheel count flag SF is 3, and the slip wheel count flag SF is
is determined to be 3, decision 172
In step 173, it is determined whether or not the right front wheel slip flag 5FFR is zero, and if it is determined that the right front wheel slip flag 5FFR is zero, in process 173, the estimated vehicle speed value Vn is calculated using the formula + V n = V F Rn xα
3 and terminate this program. If it is determined in decision 172 that the front right wheel slip flag 5FFR is not zero, then in decision 174 it is determined whether or not the front left wheel slip flag 5FFL is zero, and if the front left wheel slip flag 5FFL is zero. If it is determined, in process 175, the estimated vehicle speed value Vn is calculated using the formula: Vn=VFLnXα3, and this program ends. If it is determined in decision 174 that the left front wheel slip flag 5FFL is not zero, then in decision 176 it is determined whether or not the right rear wheel slip flag 5FRR is zero, and the right rear wheel slip flag 5FFL is determined to be zero. If it is determined that the value V of the estimated vehicle speed is
The program ends by calculating n by the formula HVn=VRRnXα, and at decision 176,
If it is determined that the right rear wheel slip flag 5FRR is not zero, in process 178, the estimated vehicle speed value V
This program ends after calculating n using the formula: Vn=VRLnXα3.

On the other hand, if it is determined in decision 171 that the slip wheel count flag SF is not three, this program is terminated.

Then, process 10 in the flowchart of FIG.
As shown in FIG. 9, the control mode setting program executed in step 5 determines at decision 179 after the start whether or not the four-wheel slip control flag CF4, which will be described later, is zero, which indicates a steady state. However, if it is determined that the four-wheel slip control flag CF4 is zero, in decision 180, the slip wheel count flag SF
is 1, and the slip wheel count flag S
If it is determined that F is 1, in process 181, the brake control execution flag EBF is set to 1, and the throttle control execution flag ETF is set to zero, and in process 182, the set slip rate for throttle control is set. Set TGTR to value TG2 and process 183
In this step, the set slip rate TGBR for brake control is set to the value TG1, and this program is ended.

Further, if it is determined in decision 180 that the slip wheel count flag SF is not 1, then in decision 184 the slip wheel count flag SF is determined to be 2.
If it is determined that the slip wheel count flag SF is 2, it is determined in decision 185 whether or not the right front wheel slip flag 5FFR is zero. And front right wheel slip flag 5FFR
is determined to be zero, decision 186
, it is determined whether or not the left front wheel slip flag 5FFL is zero, and if it is determined that the left front wheel slip flag 5FFL is zero, the left rear wheel 21L and the right rear wheel 21
Since R is slipping more than a predetermined value on the road surface, the brake control execution flag EB is set in process 187.
F is set to 1, and the throttle control execution flag ETF is set to 0, and the process proceeds to process 182.
The subsequent processes are executed sequentially in the same manner as described above, and this program ends.

On the other hand, if it is determined at decision 186 that the left front wheel slip flag 5FFL is not zero, then at decision 18, it is determined whether or not the left rear wheel slip flag 5FRL is zero, and the left rear wheel slip flag 5FFL is determined to be zero.
If it is determined that L is not zero, then the front left wheel 20L and the rear left wheel 21L are slipping more than a predetermined amount on the road surface, so in process 189, the set slip rate TGTR is set to the value TG2, and in process 194 Proceed to.

Further, if it is determined in decision 185 that the right front wheel slip flag 5FFR is not zero, then in decision 190, the right rear wheel slip flag 5FFR is determined to be non-zero.
is zero, and set the right rear wheel slip flag 5F.
If RR is determined to be zero, Decision 1
At step 91, it is determined whether or not the left front wheel slip flag 5FFL is zero, and if it is determined that the left front wheel slip flag 5FFL is not zero, the left front wheel 20L and the right front wheel 2OR slip more than a predetermined value on the road surface. has occurred, so in process 192, the set slip rate TGT
Set R to the value TG3 and proceed to process 194. Furthermore, if it is determined in decision 190 that the right rear wheel slip flag 5FRR is not zero, the right front wheel 20
Since the R and right rear wheels 21R are slipping more than a predetermined amount with respect to the road surface, in process 193, the set slip rate TGTR is set to the value TG2, and in process 194
Proceed to. In process 194, both the brake control execution flag EBF and the throttle control execution flag ETF are set to 1, and in the subsequent process 183, the target slip ratio TBR is set to the value TGI, and this program is ended. Furthermore, if it is determined in decision 188 that the left rear wheel slip flag 5FRL is zero, this means that the left front wheel 20L and the right rear wheel 21R are slipping more than a predetermined amount, and in decision 191, the left front wheel slip flag 5FRL is determined to be zero. If it is determined that 5FFL is zero, it means that the front right wheel 2OR and the rear left wheel 21L are slipping more than a predetermined amount.
7, each process after process 187 is executed in the same manner as described above, and this program ends.

On the other hand, if it is determined in decision 184 that the slip wheel count flag SF is not 2, then in decision 196 the slip wheel count flag SF is determined to be 3.
If it is determined that the slip wheel count flag SF is 3, it is determined in decision 197 whether or not the three-wheel simultaneous slip occurrence flag CF3 is zero, and the three-wheel If it is determined that the simultaneous slip occurrence flag CF3 is zero, it is determined in decision 198 whether or not the simultaneous slip count flag SFS is 3, and if it is determined that the simultaneous slip count flag SFS is not 3. In step 199, the set slip rate TGTR is set to the value TG2, and both the brake control execution flag EBF and the throttle $ control execution flag ETF are set to 1, and in the process 183, the target slip rate TBR is set to the value TGI. and exit this program. Further, if it is determined in decision 197 that the three-wheel simultaneous slip occurrence flag CF3 is not zero, and if it is determined that the simultaneous slip count flag SFS is 3 in decision 198, the set slip rate is determined in process 200. TGTR is set to the value TG2, the brake control execution flag EBF and the throttle control execution flag ETF are both set to 1, and the three-wheel simultaneous slip occurrence flag CF3 is set to 1, and process 183 is executed in the same manner as described above. Exit this program.

If it is determined in decision 196 that the slip wheel count flag SF is not 3, then decision 2
At step 01, it is determined whether or not the slip wheel count flag SF is 4. If it is determined that the slip wheel count flag SF is 4, the process proceeds to decision 202.

Also, if it is determined in decision 179 that the four-wheel slip control flag CF4 is not zero, the process advances to decision 202, and in decision 202, the four-wheel slip control flag CF4 is
It is determined whether the wheel slip control flag CF4 is 2 indicating a slip convergence state. Then, if it is determined that the four-wheel slip control flag CF4 is not 2, in decision 203, the four-wheel slip control flag C
Determine whether F4 is zero, which indicates a steady state, and
If it is determined that the wheel slip control flag CF4 is zero, in process 204, the set slip rate TG is
TR is set to 0, the brake control execution flag EBF is set to 0, the throttle control execution flag ETF is set to 1.4 wheel slip control flag CF4 is set to 1 for the slip convergence process, and the process proceeds to process 205. On the other hand, if it is determined in decision 203 that the four-wheel slip control flag CF4 is not zero, the process directly proceeds to process 205.

In process 205, the circumferential velocity values VFLn, VF
Calculate the circumferential velocity average value VAV by adding Rn, VRLn and VRRn and dividing by 4, followed by process 206
, the total deviation value ε is calculated by the formula; % formula % VAV)2, and in decision 207 it is determined whether the total deviation value ε is less than or equal to a predetermined value Za. If it is determined, the program directly advances to process 183, executes process 183 in the same manner as described above, and ends this program. If it is determined in decision 207 that the total deviation value ε is less than or equal to the value Za, in process 208 the set slip rate TGTR is set to the value T (1, 1, and the four-wheel slip control flag CF4 is set to 2). Then, it starts the built-in timer and starts measuring the elapsed time T. Then,
In the subsequent decision 210, it is determined whether the elapsed time T is greater than or equal to a predetermined time length Tx, and if it is determined that the elapsed time T is less than the time length Tx, the process 18
3 in the same manner as described above to end this program, and if it is determined that the elapsed time T is greater than or equal to the time length Tx, in process 211, the brake control execution flag E is set.
BF, throttle control execution flag ETF, 3-wheel simultaneous slip occurrence flag CF3.4-wheel slip control flag CF4
．． The slip wheel count flag SF is set to zero, the built-in timer is reset, and the process 183 is executed in the same manner as described above, and then this program is terminated. Furthermore, even if it is determined in process 201 that the slip wheel count flag SF is not 4, process 211 and process 183 are executed in the same manner as described above, and the process returns to the original state.

Then, process 10 in the flowchart of FIG.
As shown in FIG. 10, the brake heat load correction program executed at Step 6 starts at Decision 21
In step 2, it is determined whether the brake control execution flag EBF is 1, and if it is determined that the brake control execution flag EBF is zero, this program is immediately terminated and the brake control execution flag EBF is set to 1. If it is determined that the disc brakes 35A to 3 are
Temperature TBO of the 5D corresponding to the slip wheel
Among the values, the highest value is selected, the selected value is set as the highest value TBmax, and the process proceeds to process 216. In process 216, the disc brake 35
The correction coefficients X corresponding to the temperature TB of wheels A to 35D corresponding to the slip wheels are respectively read from the built-in memory, and in the subsequent process 217, the process 21
Correction coefficient y corresponding to the maximum value TBmay set in 4
is read from the built-in memory and the process proceeds to process 218. In process 218, the target slip rate TBR is calculated using the formula: TBR=(TGTR-TGBR)Xx+TGBR, and in the subsequent process 219, the target slip rate TTR is calculated using the formula;
Calculate by y+TGBR and end this program.

As shown in FIG. 11, the throttle control program executed in process 107 in the flowchart of FIG. 5 determines in decision 220 whether the throttle control execution flag ETF is zero or not. , if it is determined that the throttle control execution flag ETF is zero, in process 221, a normal throttle opening control program is executed and this program is terminated, and in decision 220, the throttle control execution flag ETF is zero. If it is determined that the
In decision 222, it is determined whether the target slip ratio TTR is zero, and if it is determined that the target slip ratio TTR is zero, in process 224, the throttle valve 14 is adjusted to fully close the throttle valve 14. The drive signal Ct is sent to the throttle actuator 13 and this program ends.

Further, in decision 222, the target slip rate T
If it is determined that TR is not zero, Decision 2
25, it is determined whether the opening degree Th of the throttle valve 14 is equal to or lower than the normal target throttle opening degree TK set according to the amount of depression of the accelerator pedal 66, and the opening degree Th of the throttle valve 14 is determined to be the normal target throttle opening degree TK or less. If it is determined that the throttle opening degree is greater than the throttle opening degree TK, in process 221, a normal throttle opening degree control program is executed and this program is terminated. If it is determined in decision 225 that the opening Th of the throttle valve 14 is equal to or lower than the normal target throttle opening TK, then in process 226 the average slip rate SAV is calculated, and in process 227 the target slip rate T ' Calculate the difference ΔS by subtracting the average slip rate SAV from T R. Then, in the subsequent process 228, the difference Δ
A throttle valve drive signal Ct corresponding to S is generated and sent to the throttle actuator 13, and this program ends.

Furthermore, process 10 in the flowchart of FIG.
As shown in FIG. 12, the brake control program executed in step 8 determines whether the brake control execution flag EBF is zero at decision 230 after starting, and determines whether the brake control execution flag EBF is zero or not. If it is determined that there is a
After setting ~35D to the released state, this program is ended, and if it is determined in decision 230 that the brake control execution flag EBF is not zero, then in decision 232 it is determined whether the left front wheel slip flag 5FFL is zero or not. to judge. If it is determined that the left front wheel slip flag 5FFL is not zero, then in process 233, the left front wheel slip flag 5FFL is adjusted using the estimated vehicle speed value Vn.
The actual slip rate SFL of L is expressed by the formula; 5FL= (VFL
n-Vn)/VFLn, followed by process 23
4, in order to match the actual slip ratio SFL and the target slip ratio TBR, the drive signal Ca is adjusted based on the comparison between the actual slip ratio SFL and the target slip ratio TBR.
and cb are selectively sent to the electric 'f11 on-off valves 51 and 52, and the process proceeds to decision 235. Further, if it is determined in decision 232 that the left front wheel slip flag 5FFL is zero, the process also proceeds to decision 235. In decision 235, it is determined whether or not the right front wheel slip flag 5FFR is zero, and if it is determined that the right front wheel slip flag 5FFR is not zero, in process 236, the estimated vehicle speed value ■n is used to determine whether or not the right front wheel slip flag 5FFR is zero. The actual slip rate SFR of the right front wheel 2OR is calculated by the formula; 5FR= (
In the subsequent process 237, based on the comparison between the actual slip ratio SFR and the target slip ratio TBR, in order to match the actual slip ratio SFR and the target slip ratio TBR,
The drive signals Cc and Cd are selectively sent to the electromagnetic on-off valves 53 and 54, and the process proceeds to decision 238.

Further, if it is determined in decision 235 that the right front wheel slip flag 5FFR is zero, the process also proceeds to decision 238. In decision 238, it is determined whether or not the left rear wheel slip flag 5FRL is zero, and if it is determined that the left rear wheel slip flag 5FRL is not zero, in process 239, the estimated vehicle speed value V
The actual slip rate SRL of the left rear wheel 21L is calculated using the formula: % formula % using Based on the comparison with the slip ratio TBR, drive signals Ce and Cf are selectively sent to the electromagnetic on-off valves 55 and 56, and the process proceeds to decision 241.

Further, if it is determined in decision 238 that the left rear wheel slip flag 5FRL is zero, the process also proceeds to decision 241. In Decision 241,
It is determined whether or not the right rear wheel slip flag 5FRR is zero, and if it is determined that the right rear wheel slip flag 5FRR is not zero, in process 242, the right rear wheel 21R is adjusted using the estimated vehicle speed value Vn. The actual slip rate SRR of 5RR=(VRRn −Vn)/VRR
n, and in the subsequent process 243, the actual slip ratio SRR and the target slip ratio TB are calculated in order to match the actual slip ratio SRR and the target slip ratio TBR.
Based on the comparison with R, drive signals Cg and ch are selectively sent to the electromagnetic on-off valves 57 and 58, and this program ends. Further, if it is determined in decision 241 that the right rear wheel slip flag 5FRR is zero, process 231 is executed in the same manner as described above and this program is terminated.

In the above example, the slip rate is calculated for a specific wheel for which a slip of a predetermined amount or more is detected, and an action is applied to the specific wheel in order to make the calculated slip rate match the set target value. However, the slip control ff device for an automobile according to the present invention does not necessarily have to do so. The estimated vehicle speed value is subtracted from the speed value, the slip amount for that specific wheel is calculated, and the drive torque acting on the specific wheel is changed in order to make the calculated slip amount match the target value. It may be done as follows.

Furthermore, in the above example, the engine output during slip control is adjusted by changing the throttle opening, but it does not necessarily have to be done this way, and instead of adjusting the throttle opening. Air fuel ratio 1 ignition timing, exhaust recirculation amount.

The adjustment may be made by changing the intake/exhaust valve opening/closing timing, boost pressure, fuel injection timing, etc.

Furthermore, although the above example is applied to a full-time four-wheel drive vehicle that is always in four-wheel drive mode,
The present invention is not limited to this, and the present invention is a part-time 4-wheel drive system that can be selectively operated between a 4-wheel drive state and a 2-wheel drive state.
It can also be applied to wheel drive vehicles.

(Effects of the Invention) As is clear from the above description, according to the slip control device for an automobile according to the present invention, as the thermal load on the brake means increases within a predetermined range, the target slip of the slip wheel in brake control increases. When the rate or target slip amount is changed to a large value and the thermal load on the braking means exceeds a predetermined value, the brake control is not substantially performed, so the thermal load on the braking means is reduced. In addition, the target slip ratio or target slip amount in the control to reduce the engine output changes to a smaller value as the thermal load on the braking means increases within a predetermined range. As a result, the reduction rate of the drive torque acting on the drive wheels in slip control does not change appreciably before and after the target slip rate or target slip amount set in brake control is increased, thereby ensuring that the It is possible to continuously perform slip control.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram showing a slip control device for an automobile according to the present invention in accordance with the claims, and FIG. 2 shows an example of the slip control device for an automobile according to the present invention. A conceptual diagram shown together with a wheel drive vehicle, FIGS. 3 and 4 are characteristic diagrams used to explain the operation of an example of the automobile slip control device according to the present invention, and FIGS. 5 to 12 are shown in FIG. 2 is a flowchart showing an example of a program executed by a microcomputer when the microcomputer is used in the control unit of the example shown in FIG. In the figure, 12 is the engine, 13 is the throttle actuator, 14 is the throttle valve, 2OL is the left front wheel, 2OR is the right front wheel, 2LL is the left rear wheel, 2. IR is the right rear wheel, 30 is the brake control unit, 35A to 35D are the disc brakes, 40 is the hydraulic pressure adjustment unit, 61 to 64 are the speed sensors, 65
is the throttle opening sensor, 67 is the accelerator opening sensor,
71 to 74 are temperature sensors, and 100 is a control unit. Patent applicant Mazda Motor Corporation Figure 3 Figure 4

Claims (1)

[Scope of Claims] Slip detection means for detecting slip of a driving wheel of an automobile with respect to a road surface; Braking means for performing a braking operation to individually apply braking force to the driving wheels; and output of an engine installed in the automobile. output adjusting means for performing an adjustment operation to change the braking means; thermal load detecting means for detecting a thermal load on the braking means; an operation of causing a braking means that applies braking force to the specific drive wheel to perform the braking operation in order to make the slip ratio or slip amount of the specific drive wheel coincide with a preset first target value; and and/or drive torque control means for causing the output adjustment means to perform the adjustment operation in order to make the slip ratio or slip amount of the specific drive wheel match a preset second target value; When a slip of a predetermined value or more is detected by the slip detection means, the first target value is increased as the thermal load detected by the thermal load detection means increases within a first predetermined range; A slip control device for an automobile, comprising: target value setting means for setting the second target value to be smaller as the detected thermal load increases within a second predetermined range.