JPH06229269A - Slip control device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the generation of tack-in phenomenon for changing the steering condition from the understeer condition to the oversteer condition suddenly at the time of turning and improve the operation stability by computing the lateral acceleration corresponding to the steering angle and the real lateral acceleration respectively, and limiting the steering so as to prevent the generation of condition that a difference between them exceeds a preset value. CONSTITUTION:In a vehicle 1, the driving torque from an engine 4 is transmitted to a left and a right front wheels 2 (a, b) through an automatic transmission 5 and a differential device 6. In this case, wheel speed of each wheel 2 (2a, 2b), 3 (3a, 3b) of the front, rear, left and right of the vehicle 1 is detected by each wheel speed sensor 9 (a-d). Steering angle of a steering wheel is detected by a steering angle sensor 10. Furthermore, the lateral acceleration corresponding to the steering angle is computed by a control device 8 on the basis of the turning radius based on the detected steering angle and the speed based on the speed of driver wheels 3. On the other hand a real lateral acceleration is computed by the control device 8 on the basis of the wheel speed of a left and a right driven wheels. The control device 8 controls to prevent the generation of condition that a difference of both lateral acceleration exceeds a preset value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle slip control device, and more particularly, it suppresses traction control to prevent tack-in so as to match the actual turning behavior of a vehicle during turning, thereby improving steering stability. Regarding things.

[0002]

2. Description of the Related Art Conventionally, in order to prevent the drive wheels from slipping due to excessive drive torque and deteriorating the acceleration performance during vehicle acceleration, the slip amount of the drive wheels is detected and the slip amount of the drive wheels is The traction control technology configured to control the engine output and the application of the braking force to the wheels so as to obtain the target value (reduce the engine output or increase the braking force) is generally put into practical use, and the anti-skid control is performed. There are quite a few that are equipped with a device and a traction control device (for example, refer to JP-A-1-197160). On the other hand, JP-A-2-38149 discloses a technique for correcting the target value of traction control to be small during turning.

In a conventional traction control device, the actual turning radius is obtained from the wheel speeds of the left and right driven wheels, the actual lateral acceleration is obtained from the actual turning radius and the vehicle speed, and the traction control is performed based only on this actual lateral acceleration. When correcting the threshold value and the control target value, traction control cannot be reliably performed in the understeer state during turning, so the steering angle-corresponding lateral acceleration corresponding to the detected steering angle and vehicle speed is set. In general, the traction control threshold value and the control target value are corrected to be small by using the correction coefficient corresponding to the steering angle-corresponding lateral acceleration.

[0004]

By the way, when the correction coefficient is set based only on the lateral acceleration corresponding to the steering angle, the steering angle is increased by the driver when the understeer tendency during turning is strong. The lateral acceleration corresponding to the angle becomes large, and the threshold value of the traction control and the control target value are corrected to be small. As a result, when the control amount of the traction control increases and the engine output decreases, the grip force of the wheels suddenly recovers and suddenly changes in the oversteer direction, a so-called tuck-in phenomenon occurs remarkably in FF vehicles, It is not preferable in terms of steering stability. An object of the present invention is to prevent the phenomenon of tuck-in and enhance steering stability in a vehicle slip control device.

[0005]

According to a first aspect of the present invention, there is provided a slip control device for a vehicle, which is traction control for suppressing a slip of a driving wheel with respect to a road surface by suppressing an output of an engine. In a vehicle slip control device that performs traction control in which a control target value is corrected according to lateral acceleration, a steering angle detection unit that detects a steering angle of a vehicle steering wheel, and wheel speeds of four wheels of the vehicle are detected. Corresponding to the steering angle based on the wheel speed detecting means, the turning angle corresponding turning radius obtained from the detected steering angle by receiving the outputs of the steering angle detecting means and the wheel speed detecting means, and the vehicle speed obtained from the wheel speed of the driven wheels. A first lateral acceleration calculating means for calculating a lateral acceleration G1; and a second lateral acceleration calculating means for receiving an output from the wheel speed detecting means and calculating an actual lateral acceleration G2 using the wheel speeds of the left and right driven wheels. It is provided with a limiting means for limiting the difference between the steering angle corresponding lateral acceleration G1 calculated by the first and second lateral acceleration calculating means and the actual lateral acceleration G2 so as not to exceed a preset value. .

According to a second aspect of the present invention, there is provided a slip control device for a vehicle according to the first aspect, wherein the set value in the limiting means is set to become smaller as the vehicle speed increases. A vehicle slip control device according to a third aspect of the present invention is the vehicle slip control device according to the first or second aspect, wherein the set value in the limiting means is set so as to decrease as the road surface μ increases.

[0007]

In the vehicle slip control device according to the first aspect of the present invention, the steering angle detecting means, the wheel speed detecting means,
A first lateral acceleration calculating means, a second lateral acceleration calculating means, and a limiting means are provided, and the first lateral acceleration calculating means calculates the turning radius corresponding to the steering angle obtained from the detected steering angle and the wheel speed of the driven wheels. The lateral acceleration G1 corresponding to the steering angle is calculated based on the vehicle speed,
The second lateral acceleration calculating means calculates the actual lateral acceleration G2 using the wheel speeds of the left and right driven wheels, and the limiting means sets the difference between the steering angle corresponding lateral acceleration G1 and the actual lateral acceleration G2 in advance. Restrict not to exceed the above. Therefore, since the steering angle-corresponding lateral acceleration G1 does not increase beyond the set value with respect to the actual lateral acceleration G2, it does not become a value that is far from the actual lateral acceleration acting on the vehicle.
Therefore, the threshold value of the traction control and the control target value are not extremely lowered, so that the phenomenon of tuck-in can be prevented and the steering stability can be improved.

In the vehicle slip control device according to the second aspect of the invention, since the set value in the limiting means is set so as to become smaller as the vehicle speed increases, the rudder that increases in proportion to the square of the vehicle speed. By providing an upper limit guard on the lateral acceleration G1 corresponding to the angle, the action and effect of claim 1 can be secured.

According to a third aspect of the present invention, there is provided a slip control device for a vehicle according to the first or second aspect, wherein the set value in the limiting means is set so as to become smaller as the road surface μ increases. Therefore, even if the actual lateral acceleration G2 increases in proportion to the road surface μ, the steering angle-corresponding lateral acceleration G1 can be prevented from increasing, and the action and effect of claim 1 or 2 can be secured.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the vehicle 1 has left and right front wheels 2a and 2b as driving wheels, and left and right rear wheels 3a and 3b as driven wheels. A V-type 6 cylinder engine 4 is mounted on the front part of the vehicle body, and drive torque from this engine 4 passes through an automatic transmission 5 and a differential device 6 through a left drive shaft 7a to a left front wheel 2a and a right drive shaft 7b. It is configured to be transmitted to each of the right front wheels 2b via each.

A control device 8 is provided for executing fuel injection control of the engine 4, ignition timing control, slip control of this vehicle (corresponding to engine traction control), and the like.
The control device 8 is provided with an engine control unit that executes fuel injection control and ignition timing control, and a slip control unit that executes slip control. Also, as sensors,
An engine speed sensor for detecting the speed of the engine 4,
Steering angle sensor 10 for detecting the steering angle of the steering wheel, the four wheels 2
A brake sensor for detecting the braking state of a, 2b, 3a, 3b, a wheel speed sensor 9a, 9b, 9c, 9d for detecting the wheel speed of the four wheels 2a, 2b, 3a, 3b, etc. are provided. The detection signal from is supplied to the control device 8.

The controller 8 has an input interface for receiving detection signals from the sensors, two microcomputers including a CPU, a ROM and a RAM, an output interface, and a drive for an igniter and a fuel injection injector. A ROM of a microcomputer of the engine control unit is prestored with a control program for the fuel injection control and ignition timing control, and tables and maps associated therewith, and the microcomputer of the slip control unit. The ROM for storing a control program for slip control, which will be described later, and various tables and maps for this slip control are stored in advance in the ROM.
The M is provided with various memories and soft counters.

The slip control executed by the slip control section of the control device 8 will be briefly described. First, the actual turning radius R is detected using the detection signals from the sensors.
r, turning radius Ri corresponding to steering angle, vehicle speed V (vehicle body speed), road surface friction coefficient μ, then lateral acceleration G (G1 or G2), and based on the lateral acceleration G, a threshold value for slip determination is set. A correction coefficient k for correcting the control target value T so as to decrease as the lateral acceleration G increases is obtained. After that, the calculation of the slip amount, the slip determination, the setting of the control target value T, the calculation of the control level FC for adjusting the engine output, etc. are executed, and the control signal of the slip control is output for the fuel control and the ignition timing control. To do.

In this slip control, the lateral acceleration G1 corresponding to the steering angle or the actual lateral acceleration G2 based on the wheel speeds of the left and right driven wheels is used.
The correction coefficient k is determined based on
The slip control threshold value (for starting and continuing) and the control target value are corrected so as to become smaller as the lateral acceleration increases. Here, in the slip control, the difference between the steering-angle-dependent lateral acceleration G1 and the actual lateral acceleration G2 during turning is strong when the understeer tendency is strong. An upper limit guard is applied to the steering angle-corresponding lateral acceleration G1 so as to be not more than (V, μ) to prevent the phenomenon of tuck-in and enhance the steering stability.

The slip control (engine traction control) executed in the slip control section will be described below with reference to the drawings starting from FIG. However, reference numeral Si in the figure
(I = 1, 2, 3, ...) Shows each step. This slip control is started when the engine 4 is started, and various detection signals such as the detected steering angle θ are read from the sensors (S1). Next, in S2, the actual turning radius R
r, the turning radius Ri corresponding to the steering angle, the vehicle speed V, and the road surface friction coefficient μ are calculated. The actual turning radius Rr is the driven wheels 3a and 3b detected by the wheel speed sensors 9c and 9d.
The wheel speeds V1 and V2 are calculated by the equation (1).
Incidentally, Td is a tread of the vehicle (for example, 1.7 m).

Rr = Min (V1, V2) × Td ÷ | V1-V2 | + 0.5Td (1) The turning radius Ri corresponding to the steering angle substantially corresponds to the turning radius in the neutral steering. Based on the absolute value of the detected steering angle θ, it is obtained by linear interpolation from the table shown in Table 1 below.

[0017]

[Table 1]

The vehicle speed V is determined by the wheel speed sensors 9c and 9c.
Wheel speeds V1, V2 of the driven wheels 3a, 3b detected from d
It is calculated as the higher of the two. The road surface friction coefficient μ is calculated based on the vehicle speed V and its acceleration Vg. A timer of 100 msec count and a timer of 500 msec are used for the calculation of the road surface friction coefficient μ, and 100 mse is elapsed from the start of the slip control until 500 msec when the vehicle body acceleration Vg does not become sufficiently large.
From the change of the vehicle speed V for 100 msec for each c, the following (2)
The vehicle body acceleration Vg is calculated by the formula
100m after 500msec when is sufficiently large
The vehicle body acceleration Vg is calculated by the following equation (3) from the change of the vehicle speed V for 500 msec every msec. Note that V (k)
Is V (k-100) 100 msec ago, V
(K-500) is the vehicle speed before 500 msec and is K
1 and K2 are predetermined constants, respectively.

Vg = K1 × [V (k) -V (k-100)] (2) Vg = K2 × [V (k) -V (k-500)] (3) The road surface friction coefficient μ is The vehicle speed V obtained as described above,
The vehicle acceleration Vg and the μ table shown in Table 2 are used for three-dimensional interpolation.

[0020]

[Table 2]

Next, in step S3, the lateral acceleration G and the correction coefficient k corresponding to the lateral acceleration are calculated. This routine will be described with reference to FIG. Although the lateral acceleration G is determined by the turning radius and the vehicle speed V, the actual turning radius Rr and the turning radius Ri corresponding to the steering angle are selectively used to obtain the lateral acceleration G. Based on the road surface condition and the driving condition, the magnitude of the tendency to deviate from the traveling line at the turning angle corresponding turning radius Ri when the vehicle turns is determined, and when the tendency is large, the turning angle corresponding turning radius Ri is selected. If the tendency is not large, the actual turning radius Rr is selected.

In the flowchart of FIG. 3, S40-
In S42, the steering angle θ, the vehicle speed V, and the road surface friction coefficient (road surface μ) are respectively determined, and the absolute value of the detected steering angle θ this time is a predetermined value θo or more, the vehicle speed V is a predetermined value Vo or more, and the road surface friction is When the coefficient μ is equal to or less than the predetermined value μo (when the tendency of understeer is strong), in S43, the steering angle corresponding lateral acceleration G1 is calculated from the steering angle corresponding turning radius Ri, and the actual lateral acceleration G2 is calculated from the actual turning radius Rr. Is calculated.
The lateral acceleration G (G1, G2) is the vehicle speed V and the turning radius R.
The following formula is used to calculate from the turning radius Ri corresponding to the steering angle or the actual turning radius Rr. G = V × V × (1 / R) × (1/127) (4)

In S44, the upper limit guard value Gt of the steering angle-corresponding lateral acceleration G1 is set to the actual lateral acceleration G2 as a preset value Δ using the vehicle speed V and the road surface μ as parameters, as shown in the following equation (5). It is calculated as a value obtained by adding (V, μ). Gt = [G2 + Δ (V, μ)] (5) Next, in S45, it is determined whether or not the steering angle corresponding lateral acceleration G1 is larger than the upper limit guard value Gt, and Yes.
In case of, the upper limit guard value Gt is given to the lateral acceleration G1 corresponding to the steering angle in S46, and the routine proceeds to S47.
When the determination result of 5 is No (when the steering angle corresponding lateral acceleration G1 is equal to or less than the upper limit guard value Gt), the process proceeds from S45 to S47.

Next, in S47, the correction coefficient k is calculated from the preset correction coefficient table of Table 3 based on the steering angle corresponding lateral acceleration G1. In addition, lateral acceleration G1, G
2. The relationship between the upper limit guard value Gt is as shown in FIG. 8, and the set value Δ (V, μ) becomes smaller as the vehicle speed V increases, as shown in FIG. , Road surface μ
It is set in advance as a map so that it becomes smaller as the value becomes higher. On the other hand, when the absolute value of the detected steering angle θ this time is less than the predetermined value θo, the vehicle speed V is less than the predetermined value Vo, or the road surface friction coefficient μ is greater than the predetermined value μo,
At S48, the actual lateral acceleration G2 is calculated by the actual turning radius Rr.
Then, in S49, the correction coefficient k is calculated from the correction coefficient table of Table 3 based on the actual lateral acceleration G2.

[0025]

[Table 3]

Next, in S4 of the flowchart of FIG. 2, the threshold value for slip determination is set. The threshold value for slip determination is set to basic threshold value × correction coefficient k, and the basic threshold value is set to the basic threshold value table 1 (Table 4) using the vehicle speed V and the road surface friction coefficient μ as parameters. (For starting slip control) or basic threshold value table 2 in Table 5
The control target basic threshold value table 1 in Table 4 indicates whether or not the slip control should be started, and the control target basic threshold value table 2 in Table 5 indicates This is for respectively determining whether or not the slip control should be continued.

[0027]

[Table 4]

[Table 5]

Next, in S5, the calculation of the slip amount is executed. The calculation of the slip amount will be described based on the flowchart of FIG. 4. In S51, the apparent slip amount S of the front wheels 2a and 2b, which are the left and right driving wheels, is calculated.
L and SR are wheel speeds Vha and V of the left and right front wheels 2a and 2b.
Each is calculated by subtracting the vehicle speed V from hb.
Next, in S52, the average slip amount SAv is calculated as the average value (SL + SR) / 2 of the slip amounts of the left and right driving wheels. Next, in S53, the maximum slip amount SHi is calculated from the maximum value of the slip amounts SL and SR of the left and right drive wheels.

Next, in S6 of FIG. 2, slip determination is executed. In this slip determination, based on the maximum slip amount SHi and the slip determination threshold value, the following (6)
When the expression is satisfied, it is determined that slip control is necessary, and the slip flag SFL is set to 1.

SHi ≧ slip determination threshold value (6) In this case, the non-control state (CFL = 0) is determined as the slip determination threshold value in step S134 of the flowchart of FIG. 5 showing the routine of S9. When it is determined that the control target basic threshold value for starting in Table 4 is used, and when it is determined that the slip control is in progress (CFL = 1), the control target basic threshold value for continuation in Table 5 is used. To be done.

[0031]

[Table 6]

[Table 7]

Next, in S7, it is determined whether or not the flag CFL = 1. If CFL = 0 (no slip control is being executed), the process immediately returns. On the other hand, in S7, CFL
If it is determined that = 1 (slip control is being executed), S8
Move to. Next, the control target value T is set in S8. The control target value T is a target value for the slip amount of the front wheels 2a, 2b, and the control target basic value obtained by three-dimensional complementation from the control target basic value table of Table 6 with the vehicle speed V and the road friction coefficient μ as parameters. The value and the correction coefficient k are calculated by the following equation. Control target value T = basic control target value × k (7)

Next, in S9, the control level FC is calculated. Regarding this control level FC, the deviation EN of the average slip amount SAv from the control target value T and its rate of change D
The basic control level FCB is determined based on EN, and the feedback correction and the initial correction of the previous value FC (k−1) are added to this to set the range to 0 to 15. In the first correction, the change rate DSAv of the average slip amount SAv is initially 0.
It is (+5) until it becomes, and from there the first time flag ST
It is (+2) until FL becomes 0. The routine of S9 will be described with reference to the flowchart of FIG. First, in S131, the deviation EN and its deviation change rate DEN are calculated by the following equations (8) and (9), respectively. Deviation EN = SAv (k) -control target value T (8) Deviation change rate DEN = DSAv = SAv (k) -SAv (k-1) (9)

Next, in S132, the basic control level FCB is calculated from the basic control level table of Table 7 based on the deviation EN and the deviation change rate DEN. Then S
At 133, feedback correction is performed to add the previous control level FC (k-1) to the current control level FC (k), then the slip control determination is performed at S134, and then the first slip control determination is performed at S135. Then, in S136, the first correction amount forcibly increasing the control level is calculated from the time when the slip of the front wheels 2a, 2b is first determined to the time when the first slip determination is eliminated.

The slip control determination routine of S134 will be described with reference to the flowchart of FIG. First, in S140, it is determined whether or not the slip flag SFL = 1 and the non-braking state is satisfied. If these conditions are satisfied, the control flag CFL indicating that the slip control is being performed is set in S141, and the process proceeds to S135. To do. On the other hand, when it is determined No in S140, it is provided in the slip control unit in S142,
Count value t1 of the first counter that counts the duration of the signal of the slip flag SFL = 0, and count of the second counter that counts the duration that the condition of FC ≦ 3 and DSAv ≦ 0.3g is satisfied. When the count value t1 is 1000 msec or more (S143: Yes) or the count value t2 is 500, the count value t2 is 500.
When it is longer than msec (S145: Yes), the control flag CFL is reset, and the process proceeds to S135.

The routine for determining the first slip control in S135 will be described with reference to the flowchart of FIG.
First, in S150, the current control flag CFL
(K) = 1 and the previous control flag CFL (k−1) =
It is determined whether or not 0, and when these conditions are satisfied, the initial flag STFL is set in S151, and the process proceeds to S136. On the other hand, when it is determined No in S150, it is determined in S152 whether or not the current slip flag SFL (k) = 0 and the previous slip flag SFL (k-1) = 1, and these conditions are satisfied. When the condition is satisfied, the initial flag STFL is reset in S153, and the process proceeds to S136.
When it is determined No in S150 and S152, the process proceeds to S136. In S136, STFL = 1 and DSA based on the initial flag STFL signal and the average slip amount change rate DSAv shown in the equation (9).
When v <0, the initial correction amount (+2) is determined. Then S
At 137, the basic control level FCB is set to the previous value FC
The feedback correction of (k-1) and the initial correction when there is an initial correction are added to set the final control level FC (k) to the range of 0 to 15.

Next, in S10 of the flowchart of FIG. 2, a slip control control signal is output from the slip control unit to the engine control unit. The control signal includes a control signal for retarding the ignition timing and a control signal for instructing fuel cut. Figure 1 shows the ignition timing.
Based on the map shown in 0, the retard amount according to the control level is determined and output. In this case, based on the map shown in FIG. 11, the maximum retard amount is limited in the region where the engine speed is high. Regarding fuel cut, one of patterns 0 to 12 in the fuel cut table of Table 8 is selected based on the control level FC. The pattern number also increases as the control level FC increases. In addition, in Table 8, a cross indicates a fuel cut. In this case, as shown in FIG. 12, a fuel cut prohibition condition is set for each control level so that the fuel cut is limited in a region where the engine speed is low.

[0038]

[Table 8]

Next, the operation of the slip control will be described. As shown in the time chart of FIG. 13, the threshold value for starting the slip control is set to a relatively high threshold value Sh based on the starting basic threshold value table, and the wheel speed of the drive wheels is changed due to disturbance or the like. Even if it becomes higher, the slip control is not started unless the threshold value Sh is exceeded. When the wheel speed of the driving wheels exceeds the threshold value Sh, the slip flag SF
If L is set and the brake is inactive, the control flag CFL and the initial flag STFL are set and the slip control is started.

When it is determined that the understeer tendency is strong in turning of the vehicle, the steering angle corresponding lateral acceleration G1 is calculated using the steering angle corresponding turning radius Ri, and the steering angle corresponding turning radius Ri is the actual turning radius. Since it is smaller than Rr, the lateral acceleration G1 corresponding to the steering angle is large, and the correction coefficient k is small, so that the threshold value Sh for start determination is low. Therefore, the slip control can be started early, and can be suppressed before the excessive understeer tendency is generated due to the early reduction of the drive torque of the drive wheels. On the other hand, when the understeer tendency is not large, the actual lateral acceleration G2 is calculated using the actual turning radius Rr, so that the slip determination threshold value and the control target value T are accurately set in accordance with the actual lateral acceleration. To be done.

Then, the average slip amount SAv is calculated based on the slip amounts of the left and right driving wheels, and the control target value T is
It is set based on the vehicle speed V and the road surface friction coefficient μ. Then, the deviation E of the average slip amount SAv from the control target value T
The basic control level FCB is set based on N and the rate of change DEN of this deviation, and the control level FC is obtained by adding the basic correction to this, and the ignition timing control and the fuel injection limit according to this control level are obtained. Control and is executed.

The initial flag STFL becomes 0 because
This is a point in time when the maximum slip amount SHi becomes equal to or less than the threshold value Sc for continuation of slip control, and at this point the slip control is once stopped. The continuation threshold value Sc is calculated by the continuation basic value table and set to a relatively low value, so that the slip can be reliably converged.

Even if the higher driving wheel wheel speed becomes equal to or lower than the continuation threshold value Sc, if the state does not continue for 1 second or longer, the control flag CFL is held in the set state.
When the wheel speeds of the drive wheels increase again with the suspension of the slip control and exceed the threshold value Sc for continuation, the slip flag SFL is set again and the slip control is restarted. In this case, the initial flag STFL is not set and the control level FC is not initially corrected. Therefore, the control level FC is initially set only by the basic control level based on the deviation EN and the deviation change rate DEN, and thereafter, the value obtained by adding the previous value to the basic control level by the feedback correction is set as the control level FC. Go. As described above, when the slip converges and the state where the slip flag SFL is not set for 1 second or more continues, the control flag CFL is set.
Is reset and the slip control for one cycle is completed.

Here, in this slip control, the lateral acceleration G1 corresponding to the steering angle is set to the actual lateral acceleration G2 by a set value Δ.
Since the upper limit guard is applied so as not to be larger than the upper limit guard value Gt obtained by adding (V, μ), the steering angle-corresponding lateral acceleration G1 is larger than the actual lateral acceleration acting on the vehicle during turning traveling with a strong understeer tendency. It will never be too far apart. As a result, the value of the correction coefficient k does not become extremely small, so that the threshold value and control level of the slip control do not extremely decrease and the engine output is not significantly suppressed. Therefore, it is possible to reliably prevent the phenomenon of tuck-in in which the understeer state suddenly changes to the oversteer state, and to improve the steering stability.

In the above embodiment, when the understeer tendency is not strong, the actual lateral acceleration G2 is obtained based on the actual turning radius Rr and the vehicle speed V, and the correction coefficient k is obtained based on the actual lateral acceleration G2. The correction coefficient k
May be calculated from the lateral acceleration corresponding to the steering angle G1 and Table 3.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle slip control device according to an embodiment.

FIG. 2 is a flowchart of a slip control routine.

FIG. 3 is a flowchart of step S3 in FIG.

FIG. 4 is a flowchart of step S5 in FIG.

5 is a flowchart of a step S9 in FIG.

FIG. 6 is a flowchart of slip control determination in S134 of FIG.

FIG. 7 is a flowchart of first slip control determination in S135 of FIG.

FIG. 8 is a time chart showing changes in lateral acceleration.

FIG. 9 is a diagram showing a map of set values Δ (V, μ).

FIG. 10 is a diagram of a map of an ignition retard amount with respect to a control level.

FIG. 11 is a diagram of a map of an ignition retard amount with respect to an engine speed.

FIG. 12 is an explanatory diagram of a fuel cut prohibition region with respect to a control level and an engine speed.

FIG. 13 is an overall operation time chart of slip control.

[Explanation of symbols]

 4 Engine 8 Control device 9a, 9b, 9c, 9d Wheel speed sensor 10 Steering angle sensor Ri Steering angle corresponding turning radius Rr Actual turning radius G1 Steering angle corresponding lateral acceleration G2 Actual lateral acceleration Gt Upper limit guard value Δ (V, μ) setting Value FC Control level FCB Basic control level Sh Slip control start threshold value Sc Slip control continuation threshold value

Claims (3)

[Claims] 1. A traction control for suppressing a slip of a driving wheel on a road surface by suppressing an output of an engine, wherein a threshold value of the traction control and a control target value are corrected according to a lateral acceleration. In a vehicle slip control device for performing traction control, a steering angle detecting means for detecting a steering angle of a steering wheel of the vehicle, a wheel speed detecting means for detecting wheel speeds of four wheels of the vehicle, the steering angle detecting means and wheel speed detection. First lateral acceleration calculating means for receiving the output of the means and calculating the steering angle corresponding lateral acceleration G1 based on the turning angle corresponding turning radius obtained from the detected steering angle and the vehicle speed obtained from the wheel speed of the driven wheels; Second lateral acceleration calculating means for receiving the output of the wheel speed detecting means and calculating the actual lateral acceleration G2 using the wheel speeds of the left and right driven wheels; and the steering angle calculated by the first and second lateral acceleration calculating means. Slip control system for a vehicle, characterized in that it comprises a limiting means for the difference 応横 acceleration G1 and actual lateral acceleration G2 is limited so as not to exceed a preset value. 2. The slip control device for a vehicle according to claim 1, wherein the set value in the limiting means is set so as to become smaller as the vehicle speed increases. 3. The slip control device for a vehicle according to claim 1, wherein the set value in the limiting means is set so as to become smaller as the road surface μ increases.