JPH0666173A - Slip controller for vehicle - Google Patents

Abstract

PURPOSE:To permit the early completion of slip control, keeping the slip control continuation judgement threshold value low, in the slip control for a vehicle. CONSTITUTION:In the slip control routine in the slip control part for a controller for an engine, the reset of a slip flag SFL for executing the engine output control in the slip control is judged (S7) and a timer TM is operated from the reset time point, and during the time where the state where the max. slip quantity SHI is larger than the respin judgement threshold value which is larger than the continuation judgement threshold value continues, the timer TM is counted up (S10, S11), and when the count value TM reaches a prescribed time T0 (S12), the control flag CFL is resest (S13), and the slip control in execution is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for a vehicle, and more particularly to a device for preventing a substantial execution period of slip control from being prolonged due to hunting or disturbance.

[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).

The applicant of the present application has filed an earlier application (Japanese Patent Laid-Open No. 2-33).
No. 4751), when the slip amount of the driving wheels becomes equal to or greater than the threshold for starting, feedback control for reducing the engine output is started in order to suppress the slip amount, and thereafter, the slip amount is the threshold for continuation determination. A slip control device for a vehicle has been proposed in which the slip control being executed is terminated when the state below the value continues for a predetermined time. For reference, Japanese Utility Model Laid-Open No. 3-24456 discloses a vehicle excess drive wheel that gradually reduces the threshold value of the slip amount during feedback control for reducing the slip amount of the drive wheel of the vehicle to an allowable level. An anti-slip device is described.

[0004]

In the vehicle slip control device proposed by the applicant of the present invention, feedback control hunting is performed even when the slip amount of the drive wheels has become sufficiently low as a result of the feedback control. If the slip amount instantaneously becomes equal to or more than the threshold value for continuation determination due to the influence of external disturbance or the like, the timer that counts the predetermined time is reset, so that the slip control being executed does not end and the engine is stopped. There is a problem in that the driving force of the driving wheels is suppressed via this.

For example, when the traveling from the high μ road to the low μ road is completed, the feedback control for suppressing the slip amount is delayed, so that the driving force is suppressed for a relatively long time. Therefore, there is a measure to set the continuation determination threshold value to a high value, but in this case, it is difficult to make the slip amount converge to a desired low state, and this cannot be an effective measure. An object of the present invention is to enable a slip control device of a vehicle to effectively execute slip control,
In addition, the started slip control can be ended early.

[0006]

According to a first aspect of the present invention, there is provided a vehicle slip control device for driving a drive wheel such that the slip amount reaches a target value when the slip amount of the drive wheel with respect to a road surface exceeds a predetermined threshold value. In a vehicle slip control device having a slip control means for controlling the slip amount, a slip amount detecting means for detecting a slip amount of the drive wheel is provided, and the slip controlling means is a slip amount detected by the slip amount detecting means. However, the slip control during execution is continued for a predetermined time from the time when it becomes below the predetermined threshold value, and when it is below the respin determination threshold value larger than the predetermined threshold value. Is configured to terminate.

According to a second aspect of the present invention, there is provided a vehicle slip control device according to the first aspect, wherein the predetermined threshold value is used for continuation determination for determining whether or not the ongoing slip control should be continued. It is characterized by being a threshold value.

According to a third aspect of the present invention, there is provided a slip control device for controlling a drive wheel so that the slip amount reaches a target value when the slip amount of the drive wheel with respect to a road surface exceeds a predetermined threshold value. In a vehicle slip control device comprising: a slip amount detection means for detecting a slip amount of the drive wheel is provided, and the slip control means,
After the control for controlling the drive of the drive wheels is started, when the slip amount detected by the slip amount detecting means becomes equal to or less than the predetermined threshold value, a re-spin determination threshold larger than the predetermined threshold value is determined. A value is set, and thereafter, when the detected slip amount continues for a predetermined time and is less than or equal to the re-spin determination threshold value, the slip control being executed is ended.

[0009]

In the vehicle slip control device according to the first aspect of the present invention, the slip amount detecting means detects the slip amount of the drive wheel, and the slip control means detects the slip amount detected by the slip amount detecting means. However, it continues for a predetermined time from the time it becomes below the predetermined threshold value,
When the re-spin determination threshold value is equal to or larger than the predetermined threshold value and is equal to or smaller than the re-spin determination threshold value, the slip control being executed is ended. Therefore, the predetermined threshold value is set to be relatively low, and slip control by feedback for early reduction of the slip amount is executed, while ensuring that the end timing of the slip control being executed is delayed due to hunting or disturbance. Can be prevented. The predetermined threshold value is a continuation determination threshold value (end determination threshold value) for determining whether or not the slip control being executed should be continued (claim 2).

According to another aspect of the vehicle slip control device of the present invention, the slip amount detecting means detects the slip amount of the drive wheel, and the slip control means detects the slip amount after starting the control for controlling the drive of the drive wheel. When the slip amount detected by the means becomes equal to or less than the predetermined threshold value, a re-spin determination threshold value larger than the predetermined threshold value is set, and the slip amount detected thereafter is set to a predetermined time period. When the re-spin determination threshold value is not exceeded, the slip control being executed is terminated. Therefore, the same action and effect as the first aspect can be obtained.

[0011]

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 for executing fuel injection control of the engine 4, ignition timing control, slip control of this vehicle, 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. Further, as sensors, an engine rotation speed sensor that detects a rotation speed of the engine 4 and a steering angle sensor 1 that detects a steering angle of a steering wheel
0, a brake sensor for detecting the braking state of the four wheels 2a, 2b, 3a, 3b, the four wheels 2a, 2b, 3a, 3b
Wheel speed sensors 9a, 9b, 9c, 9 for detecting wheel speeds of
d and the like are provided, and detection signals from these sensors are supplied to the control device 8.

The control device 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 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 outline of the slip control executed by the slip control section of the control device 8 will be 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, and based on the lateral acceleration G, a threshold value for slip determination (control start threshold) Value or continuation determination threshold value) and the control target value T are corrected so as to decrease as the lateral acceleration G increases.
Ask for. After that, slip amount calculation, slip determination,
The control target value T is set, the control level FC for adjusting the engine output is calculated, and control signals for slip control are output for fuel control and ignition timing control. Furthermore,
As a characteristic configuration of the slip control of the present application, the slip amount of the drive wheels is continued for a predetermined time from the time when the slip amount of the drive wheels is equal to or less than the threshold value for continuation determination, and the slip amount of the drive wheels is more than the threshold value for continuation determination When it is below the large re-spin determination threshold value, the slip control being executed is ended.

A flowchart of slip control executed by the slip control unit will be described below with reference to FIGS. However, reference numeral Si in the drawing (i = 1, 2, 3,
・ ・) Shows each step. This slip control is started when the engine 4 is started, various detection signals are read from the sensors (S1), and then S2.
At, a calculation for obtaining the actual turning radius Rr, the turning angle-corresponding turning radius Ri, the vehicle speed V, and the road friction coefficient μ is executed. The actual turning radius Rr is calculated by Formula 1 using the wheel speeds V1 and V2 of the driven wheels 3a and 3b detected by the wheel speed sensors 9c and 9d.
Is calculated by Incidentally, Td is a tread of the vehicle (for example, 1.7 m).

[0016]

## EQU1 ## Rr = Min (V1, V2) × Td ÷ | V1-
V2 | + 0.5Td The turning angle-corresponding turning radius Ri substantially corresponds to the turning radius in neutral steering, and this is based on the absolute value of the steering angle θh detected by the steering angle sensor 10,
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 formula 2
Then, the vehicle body acceleration Vg is calculated by the following method, and after 500 msec when the vehicle body acceleration Vg becomes sufficiently large, 100 m
The vehicle body acceleration Vg is calculated from the change of the vehicle speed V for 500 msec every sec by the following mathematical formula 3. It should be noted that V (k) is at present, V (k-100) is 100 msec before, and V (k-
500) is each vehicle speed before 500 msec, K1, K2
Are predetermined constants.

[0019]

## EQU2 ## Vg = K1 × [V (k) -V (k-100)]

## EQU3 ## Vg = K2 × [V (k) -V (k-500)] 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, the lateral acceleration G and the lateral acceleration corresponding correction coefficient k are calculated in S3, and 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. Figure 3
When the absolute value of the detected steering angle θh is equal to or greater than the predetermined value θho, the vehicle speed V is equal to or greater than the predetermined value Vo, and the road surface friction coefficient μ is equal to or less than the predetermined value μo in the flowchart of FIG. The lateral acceleration G is calculated (S31-
S34) If the above conditions are not satisfied, the lateral acceleration G is calculated using the actual turning radius Rr (S31 to S3).
3, S35), and then the correction coefficient k based on the lateral acceleration G is calculated (S36).

The lateral acceleration G is calculated from the detected vehicle speed V and the turning radius R (the turning radius Ri corresponding to the steering angle or the actual turning radius Rr) by the following equation.

G = V × V × (1 / R) × (1/127) Next, in S36, the correction coefficient k based on the lateral acceleration G.
Is calculated from the correction coefficient table of Table 3 set in advance.

[0023]

[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 the basic threshold value × correction coefficient k, and the basic threshold value is defined by the basic threshold value table 1 (Table 4 (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.

[0025]

[Table 4]

[Table 5]

Next, in S5, the calculation of the slip amount is executed. The calculation of the slip amount will be described with reference to the flowchart of FIG. 4. The left and right front wheels 2a, 2b will be described.
The slip amounts SL and SR are calculated by subtracting the vehicle speed V from the wheel speeds Vha and Vhb of the left and right front wheels 2a and 2b (S51), and then the average slip amount SAv is calculated from the average value of the slip amounts SL and SR. It is calculated (S52), and then the maximum slip amount SHi is calculated from the higher value of the slip amounts SL and SR (S53). Next, in S6, slip determination is executed. In this slip determination, it is determined that slip control is necessary and the slip flag SFL is set to 1 when the following expression 6 is satisfied based on the maximum slip amount SHi and the threshold value for slip determination.

[0027]

[Expression 6] SHi ≧ slip determination threshold value In this case, as the slip determination threshold value, the non-control state (CFL = 0) is determined in step S164 of the flowchart of FIG. 5 showing the routine of S16. 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 when the slip control is in progress (CFL = 1). It

[0028]

[Table 6]

[Table 7]

Next, S7 to S14 show a characteristic configuration of the present application, and it is determined whether or not the slip flag SFL has changed from "1" to "0", that is, the slip flag SFL.
Is determined (S7), the process proceeds to S9 if No, and the timer TM (however, its count value is TM) is started if Yes (S8) and then proceeds to S15. . That is, the timer TM is started every time the maximum slip amount SHi becomes equal to or less than the continuation determination threshold Sc. Slip flag SFL is "1" or "0"
If it is, it is determined whether the flag CFL is in the set state (S9), and if the flag CFL is in the reset state, S15.
Move to. On the other hand, when the flag CFL is in the set state, the maximum slip amount SHi is the re-spin determination threshold value Ss.
It is determined whether or not (S10).

The re-spin determination threshold value Ss is set to a value obtained by adding +2 to the continuation determination threshold value Sc, for example,
A value obtained by adding +2 to the continuation determination threshold value Sc read from Table 5 is used. Next, as a result of the determination in S10, N
When it is o, the process proceeds to S14, the timer TM is reset, and then the process proceeds to S15. As a result of the determination in S10, Ye
When s, the timer TM is counted up (S1
1) Next, it is determined whether or not the value TM of the timer TM is equal to or greater than the predetermined value T0 (S12), and if it is less than the predetermined value T0, the process proceeds to S15.

As described above, the timer TM is started every time the maximum slip amount SHi becomes equal to or less than the continuation determination threshold value Sc, and the state in which the maximum slip amount SHi is equal to or less than the re-spin determination threshold value Ss continues. The timer TM is counted up, and the count value TM of the timer TM is a predetermined value T0 (however, this is measured by the timer 72 of FIG.
(It is desirable to set it to be equal to 00 msec), the process proceeds from S12 to S13 to reset the flag CFL, that is, the slip control being executed is ended, and the process returns. Until the count value TM of the timer TM reaches the predetermined value T0, or until the flag CFL is reset by the flip-flop 69 in FIG.
1 to S6, S7 to S12, and S15 to S17 are repeatedly executed.

Next, in S15, the control target value T is set. This control target value T is a target value for the slip amount of the front wheels 2a, 2b, and is 3 from the control target basic value table of Table 6 with the vehicle speed V and the road friction coefficient μ as parameters.
It is calculated by the following equation from the control target basic value obtained by dimension complementation and the correction coefficient k.

[Equation 7] Control target value T = Control target basic value × k

Next, in S16, the control level FC is calculated. For this control level FC, the basic control level FCB is determined based on the deviation EN of the average slip amount SAv from the control target value T and the rate of change DEN, and the feedback correction of the previous value FC (K-1) is performed. Taking into account the first correction and, the range is set to 0-15. This S16
The routine will be described with reference to the flowchart of FIG. First, in S161, the deviation EN and its deviation change rate DEN are calculated by the following equation.

[Equation 8] Deviation EN = SAv (K) -Control target value T

[Equation 9] Deviation change rate DEN = DSAv = SAv (K)-
SAv (K-1)

Next, in S162, 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 163, 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 S165. Next, in S166, an initial 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 equivalent circuit for the slip control determination in S164 is as shown in FIG. 6. In FIG. 6, the AND circuit 68 outputs the set signal to the flip-flop 69 when the slip flag SFL = 1 and the non-brake state is set. , AN
The D circuit 70 outputs “1” when FC ≦ 3 and DSAv ≦ 0.3 g. Further, the OR circuit 71 outputs the signal of the slip flag SFL = 0 to 10 via the counter 72.
The signal is continuously received for 00 msec or the output signal "1" is output from the AND circuit 70 through the counter 73 for 500 mse.
When c is continuously received, a reset signal is output to the flip-flop 69. The flip-flop 69 outputs a signal of control flag CFL = 1 (during slip control) when receiving the set signal.

The equivalent circuit for the first slip control determination in S165 is as shown in FIG. 7, and in FIG.
Outputs a set signal to the flip-flop 75 when the current control flag CFL (K) = 1 and the previous control flag CFL (K-1) = 0, and the AND circuit 76 outputs the current slip flag SFL ( When K) = 0 and the previous slip flag SFL (K-1) = 1, the reset signal is output to the flip-flop 75. The flip-flop 75 receives the set signal and receives the first flag STFL = 1.
The signal of (during initial control) is output. In S166,
Based on the initial flag STFL signal and the average slip amount change rate DSAv shown in Formula 9, the initial correction amount (+2) is determined when STFL = 1 and DSAv <0. Next, in S167, the initial correction amount is added to the feedback-corrected control level FC to calculate the final control level FC.

Next, in S17 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. For the ignition timing, see FIG.
Based on the map shown in, the retard amount is determined and output according to the control level. In this case, based on the map shown in FIG. 9, 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. 10, 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]

The operation of the slip control described above will be described with reference to the time chart of FIG. 11. The basic value of the slip control start threshold value Sh for shifting from the non-controlled state to the slip control is It is calculated from the starting basic target value table of Table 4 and set to a relatively high threshold value. Therefore, even if the wheel speed of the drive wheels becomes high (the maximum slip amount SHi is large) due to disturbance or the like, the slip flag SFL is not exceeded as long as the start threshold Sh is not exceeded.
Is not set and slip control does not start. When the wheel speed of the drive wheels exceeds the threshold value Sh for starting, the slip flag SFL is set, and if the brake is in the inoperative state, the control flag SFL and the initial flag STFL are set and the slip control is started. Become.

Moreover, when the vehicle is turning, the steering angle θ
When it is determined from the values of h, the vehicle speed V, and the road surface friction coefficient μ that the tendency to deviate from the traveling line at the turning radius Ri corresponding to the turning angle is large (for example, the antesteering tendency is large), the turning radius Ri corresponding to the steering angle is set. The lateral acceleration G of the vehicle is calculated using this. In this case, the turning radius Ri corresponding to the steering angle is the actual turning radius R
Since it is smaller than r, the lateral acceleration G that is obtained becomes large and the correction coefficient k becomes small, so the slip control start threshold value Sh becomes low. Therefore, even if the slip amount itself is not so large, the slip control is started early, and this can be suppressed before the excessive understeer tendency is generated due to the early reduction of the drive torque of the drive wheels.

As described above, the vehicle speed V, the road surface friction coefficient μ and the average slip amount SAv are obtained, and the vehicle speed V and the road surface friction coefficient μ are obtained.
Based on the control target value T, the control target value T is determined, and the deviation EN of the average slip amount SAv from this control target value T and its change rate DEN
Based on these, the control level FC with the initial correction taken into consideration is obtained, and the ignition timing and the fuel injection limit according to the control level FC are executed. The initial correction is (+5) until the change rate DSAv of the average slip amount SAv becomes 0 for the first time, and (+2) until the initial flag STFL becomes 0. By this first correction, the control amount is forcibly increased, and the slip can be quickly converged.

The initial flag STFL becomes 0 because
This is the time when the maximum slip amount SHi due to the higher driving wheel wheel speed becomes equal to or less than the slip control continuation determination threshold value Sc. Therefore, when it is determined that the tendency to deviate from the travel line at the turning radius Ri corresponding to the steering angle is large during turning, the correction coefficient k becomes small, so the control target value T becomes small, and the slip amount is reduced to this target value. Since it is lowered, the amount of reduction in the drive torque of the drive wheels is increased, and the understeer tendency can be eliminated at an early stage. The continuation determination threshold value Sc is set to a relatively low threshold value by the basic value thereof being calculated by the continuation determination basic value table. Further, when it is determined that the tendency to deviate from the traveling line at the turning radius corresponding to the steering angle Ri is large, the correction coefficient k becomes small, so that the continuation determination threshold value Sc becomes further lower, and the slip surely converges. Control can be continued.

On the other hand, when the tendency to deviate from the traveling line at the turning radius Ri corresponding to the steering angle is not large, the actual turning radius Rr
Since the lateral acceleration G is calculated by using, the slip determination threshold value and the control target value T are accurately corrected by matching with the actual lateral acceleration. Even if the higher drive wheel wheel speed becomes equal to or lower than the continuation threshold Sc, the control flag CFL is maintained in the set state if the state is not longer than 1 second. Then, as the reduction amount of the drive wheel drive torque decreases, the drive wheel wheel speed increases again, and when it exceeds the continuation threshold value Sc, the slip flag SFL is set again and the control is continued. In this case, the initial flag is not set and the control level FC is not 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 control level FC is set by adding the previous value to the basic control level by feedback correction. I will go. In this way, if the slip continues to converge and the state in which the slip flag SFL is not set for 1 second or longer continues, the control flag CFL
Becomes 0 and the slip control ends.

Here, as a configuration peculiar to the present application, the configuration shown in FIG.
Since S7 to S14 are provided, the higher drive wheel wheel speed (maximum slip amount SHi) is the threshold value Sc for continuation determination.
When the higher drive wheel wheel speed is equal to or lower than the re-spin determination threshold Ss continuously for a predetermined time (for example, 1 second) from the time when the control flag CFL becomes equal to or less than the following value, the control flag CFL is reset to 0. Since the slip control being executed is terminated, after the slip of the driving wheels is sufficiently converged, due to hunting or disturbance, as shown by a chain line H in FIG. 11, the higher drive is instantaneously or repeatedly performed. Even if the wheel speed becomes equal to or higher than the continuation determination threshold value Sc, if the state of being equal to or lower than the re-spin determination threshold value Ss continues for a predetermined time, the control flag CFL is reliably reset and the slip control ends.

In this way, the value of the continuation determination threshold value Sc can be set relatively low to effectively execute the engine output control for suppressing the slip, and the continuity determination threshold value Sc of the continuity determination threshold value Sc can be set. In addition, since the re-spin determination threshold value Ss is introduced, when the maximum slip amount SHi is equal to or less than the re-spin determination threshold value Ss for a predetermined time, the slip control being executed is terminated. It is possible to reliably prevent the control end timing from being delayed due to hunting or disturbance, and to advance the control end timing.

Next, another embodiment in which a part of the above embodiment is modified will be described. In setting the threshold value for slip determination in S4 of FIG. 2, the control flag CFL = 0
When the control flag CFL = 1 and the initial flag STFL = 1, the basic threshold value table 1 (for slip control) of Table 4 is used in the case of When the control flag CFL = 1 and the initial flag STFL = 0, the basic threshold value table 3 (for re-spin determination) in Table 9 is used. The basic threshold value table 3 in Table 9 is
Numerical values are set larger than those of the basic threshold value table 2 in Table 5.

[0047]

[Table 9]

Then, in the slip determination of S6 of FIG.
Although the three types of slip determination threshold values are selectively used, the configuration is the same as that of the above embodiment except for the slip determination threshold value described above.

When the threshold value for slip determination is set in this way, as shown in FIG. 12, after the substantial slip control for controlling the drive of the driving wheels is started, the threshold value for continuation determination is first used based on the threshold value. The slip determination is performed, and then the slip determination is performed based on the re-spin determination threshold value Ss. Control flag CFL = 1 and initial flag ST
When the FL is in the reset state, the slip flag S
Whenever FL is reset, the timer TM starts, and if the state where the maximum slip amount SHi is less than or equal to the re-spin determination threshold value Ss continues for a predetermined time T0 (T0 = 1 second in this embodiment), the The slip control being executed is ended. Initially, when the initial flag STFL is in the set state, the slip determination is performed based on the slip continuation determination threshold Sc, so that the slip convergence can be accelerated, and thereafter, the slip determination that is larger than the continuation determination threshold Sc is performed. Since the slip determination is performed based on the spin determination threshold value Ss, it is less susceptible to the effects of hunting and disturbance, and the end timing of the slip control during the execution can be advanced.

[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 a routine of step S3 in FIG.

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

5 is a flowchart of a routine of step S13 in FIG.

FIG. 6 is an equivalent circuit diagram of step S134 in FIG.

FIG. 7 is an equivalent circuit diagram of step S135 of FIG.

FIG. 8 is a diagram of a map of an ignition retard amount with respect to a control level.

FIG. 9 is a diagram of a map of ignition retard amount with respect to engine speed.

FIG. 10 is an explanatory diagram of a fuel cut prohibition region with respect to a control level and an engine speed.

FIG. 11 is an operation time chart of slip control.

FIG. 12 is an operation time chart of slip control according to another embodiment.

[Explanation of symbols]

 4 engine 8 control device 9a, 9b, 9c, 9d wheel speed sensor 10 steering angle sensor FC control level FCB basic control level Sh slip control start threshold value Sc slip control continuation determination threshold value Ss re-spin determination threshold value SHi maximum slip amount

Claims (3)

[Claims] 1. A slip control device for a vehicle, comprising: slip control means for controlling the drive of the drive wheels such that the slip amount reaches a target value when the slip amount of the drive wheels with respect to a road surface exceeds a predetermined threshold value. In, a slip amount detecting means for detecting the slip amount of the drive wheel is provided, and the slip control means is a time point when the slip amount detected by the slip amount detecting means is equal to or less than the predetermined threshold value. From a re-spin determination threshold value larger than the predetermined threshold value, the slip control being executed is ended. Slip control device. 2. The vehicle according to claim 1, wherein the predetermined threshold value is a continuation determination threshold value for determining whether to continue the slip control that is being executed. Slip control device. 3. A slip control device for a vehicle, comprising: slip control means for controlling the drive of the drive wheels such that the slip amount reaches a target value when the slip amount of the drive wheels with respect to the road surface exceeds a predetermined threshold value. In the above, a slip amount detecting means for detecting a slip amount of the drive wheel is provided, and the slip control means, after starting the control for controlling the drive of the drive wheel, the slip amount detected by the slip amount detecting means is the predetermined value. When the threshold value becomes equal to or less than the threshold value, a re-spin determination threshold value larger than the predetermined threshold value is set, and thereafter, the detected slip amount continues for a predetermined time to determine the re-spin determination threshold value. A slip control device for a vehicle, which is configured to terminate the slip control being executed when the value is less than or equal to a value.