JP3316245B2 - Vehicle slip control device - Google Patents

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 setting a control amount of traction control by using an average value of slip amounts of left and right drive wheels when turning. The present invention relates to a method of using a weighted average value obtained by adding a weight to a slip amount.

[0002]

2. Description of the Related Art Conventionally, during acceleration of a vehicle, in order to prevent the drive wheels from slipping due to excessive driving torque and deteriorating the acceleration, the slip amount of the drive wheels is detected and the slip amount of the drive wheels is detected. as a target value, controls the application of braking force to the engine output and the wheel (lowering the engine output, or the braking force increased to a) traction control technology thus constructed is generally commercialized, also, anti-skid Not a few devices include a control device and a traction control device (for example, see Japanese Patent Application Laid-Open No. 1-197160).

In the slip control device, the slip determination is made based on the maximum slip amount among the slip amounts of the left and right driving wheels. Is set based on the difference between the average value of the slip amounts of the drive wheels and the target slip amount. For example, Japanese Patent Application Laid-Open No. 1-215636 discloses a technique for setting a control amount of traction control in accordance with a deviation amount of a drive wheel slip amount from a target value.

[0004]

However, when the vehicle is turning on a high μ road surface and a considerably large lateral acceleration is applied, the inner drive wheels tend to float and the slip amount becomes very large. In this case, the slip control is started, and the control amount of the traction control is set based on the difference between the average value of the slip amounts of the left and right driving wheels and the target value, but the average value of the slip amounts becomes large. However, there is a problem that the control amount of the traction control is large, the degree of suppression of the engine output is increased, and the acceleration performance is reduced. An object of the present invention is to make it possible to appropriately set the control amount of the slip control at the time of turning traveling in association with the road surface μ.

[0005]

According to a first aspect of the present invention, there is provided a vehicle slip control apparatus for performing traction control for suppressing slip of a drive wheel on a road surface by suppressing an engine output. Wheel speed detecting means for detecting the wheel speeds of the four wheels, slip amount calculating means for receiving the output of the wheel speed detecting means to determine the slip amount of the left and right drive wheels, and calculating the slip amount according to the running state of the vehicle. A target value setting means for setting a target value, and an average value of the slip amounts of the left and right driving wheels is obtained in response to an output of the slip amount calculating means, and the average value is compared with the target value obtained by the target value setting means. First control amount setting means for obtaining a control amount of traction control during straight running based on the difference; road surface μ detecting means for detecting a friction state of the road surface; Receiving the output of the means, as the average value of the slip amount of the left and right driving wheels, obtains a weighted average value obtained by adding a weight related to the road surface μ to the slip amount of the left and right driving wheels, and calculates the weighted average value and the target value setting means. And a second control amount setting means for obtaining a control amount of the traction control at the time of turning traveling based on the difference from the target value obtained in step (1).

[0006] slip control system as claimed in claim 2 vehicle, the apparatus of claim 1, wherein the second control amount setting means, the left
When calculating the average value of the slip amount of the right drive wheel, when the road surface friction state is high μ, the weight of the slip amount of the inner drive wheel is smaller than the weight of the slip amount of the outer drive wheel. It is composed. The slip control device for a vehicle according to claim 3 is the device according to claim 1,
The second control amount setting means calculates a slip amount of the left and right drive wheels.
For obtaining the average value, when even a low μ when the road surface friction state is high μ also driving outside the weight of the slip amount of the inner drive wheel
It is configured to add a larger weight to the weight of the slip amount of the driving wheel .

[0007]

According to the first aspect of the present invention, there is provided a vehicle slip control device comprising: a wheel speed detecting means; a slip amount calculating means; a target value setting means; a first control amount setting means; , A second control amount setting means, wherein the first control amount setting means obtains an average value of the slip amounts of the left and right driving wheels, and, based on a difference between the average value and a target value, traction during straight running. The control amount of control is obtained, and the second control amount setting means calculates, as the average value of the slip amounts of the left and right drive wheels, a weighted average value obtained by adding a weight related to the road surface μ to the slip amount of the left and right drive wheels. Then, based on the difference between the weighted average value and the target value, the control amount of the traction control during turning is calculated. Therefore, when turning,
Even if a large slip amount occurs in the inner driving wheels, by appropriately performing the weighting related to the road surface μ, an appropriate weighted average value can be obtained, and the control amount of the traction control can be appropriately set.

According to a second aspect of the present invention, in the vehicle slip control device, the second control amount setting means includes a pair of right and left drive wheels.
When obtaining the average value of-up amount, when the road surface friction state high μ is the weight of the slip amount of the inner driving wheel of the outer driving wheel scan
Since the weighting of the lip amount is configured to add a smaller weight, it is possible to prevent the average slip amount from being set excessively with a large slip amount of the inner drive wheels when turning on a high μ road surface. As a result, the control amount of the traction control can be suppressed low, and the acceleration can be improved. When the reference of the control amount setting of the traction control is based on the low μ road surface, as described above, the weight of the slip amount of the inner drive wheel is smaller than the weight of the slip amount of the outer drive wheel. It is desirable to add.

[0009] In the slip control apparatus for a vehicle according to claim 3, wherein the second control amount setting means, the right and left drive wheels Sri
When calculating the average value of the slip amount, the weight of the slip amount of the inner drive wheels is not limited when the road friction state is high μ or low μ.
The weight of the slip amount of the outer driving wheel is increased so as to be larger. When the reference for setting the control amount of the traction control is based on the high μ road surface, as described above, the weight of the slip amount of the inner drive wheel is set to the outer side.
By adding a larger weight to the weight of the slip amount of the drive wheel , the average slip amount is set to be large, the control amount of the traction control is increased, the engine output is suppressed, and the steering stability can be improved.

[0010]

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

A control device 8 for executing fuel injection control and ignition timing control of the engine 4 and slip control (corresponding to engine traction control) of the vehicle is provided.
The control device 8 is provided with an engine control unit for executing fuel injection control and ignition timing control, and a slip control unit for executing 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, 2b, 3a, 3b, brake sensors for detecting the braking state of the four wheels 2a, 2b, 3a, 3b, and wheel speed sensors 9a, 9b, 9c, 9d for detecting the wheel speed of the four wheels 2a, 2b, 3a, 3b, Is supplied to the control device 8.

The control device 8 includes 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. The control program for the fuel injection control and the ignition timing control and tables and maps associated therewith are stored in advance in the ROM of the microcomputer of the engine control unit. The ROM stores a control program for slip control described later and various tables and maps for this slip control in advance.
M is provided with various memories and soft counters.

The slip control executed by the slip control unit of the control device 8 will be briefly described. First, the actual turning radius R is calculated using the detection signals from the sensors.
r, a turning radius corresponding to a steering angle, a vehicle speed V (vehicle speed), a road surface friction coefficient μ, a lateral acceleration G is determined, and a slip determination threshold value and a control target value T are determined based on the lateral acceleration G. Is calculated so as to be lower as the lateral acceleration G increases. Thereafter, calculation of slip amount, determination of slip, setting of control target value T, calculation of control level FC for adjusting engine output, and the like are executed, and a control signal of slip control is output for fuel control and ignition timing control. I do.

This slip control uses a weighted average value obtained by adding a weight relating to the road surface μ to the slip amount of the inner and outer drive wheels as an average value of the slip amount of the inner drive wheel and the outer drive wheel during turning. By setting the control level (control amount) of the slip control using the weighted average value, the acceleration property during turning is enhanced.

Hereinafter, slip control (engine traction control) executed in the slip control unit will be described with reference to FIG. 2 and subsequent drawings. However, the symbol Si in the figure
(I = 1, 2, 3,...) Indicates each step. The 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
Calculation for determining r, the turning radius corresponding to the steering angle Ri, the vehicle speed V, and the road surface friction coefficient μ is executed. The actual turning radius Rr is determined by the driven wheels 3a, 3b detected by the wheel speed sensors 9c, 9d.
Is calculated by the equation (1) based on the wheel speeds V1 and V2.
Here, Td is the tread (for example, 1.7 m) of the vehicle.

Rr = Min (V1, V2) × Td ÷ | V1-V2 | + 0.5Td (1) The steering angle-corresponding turning radius Ri substantially corresponds to the turning radius in the neutral steering, and this is the current turning radius. 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 and V2 of the driven wheels 3a and 3b detected from d.
Is calculated as the higher value of The road friction coefficient μ is calculated based on the vehicle speed V and the acceleration Vg. For the calculation of the road surface friction coefficient μ, a timer of 100 msec count and a timer of 500 msec count are used, and 100 msec from the start of the slip control until 500 msec elapse when the vehicle body acceleration Vg does not become sufficiently large.
From the change in the vehicle speed V for 100 msec for each c, the following (2)
The vehicle acceleration Vg is obtained by the following equation.
After 500 msec elapses when the
The vehicle acceleration Vg is obtained from the change in the vehicle speed V for 500 msec every msec by the following equation (3). In addition, V (k)
Is the current time, V (k-100) is 100 msec before, V
(K-500) is each vehicle speed before 500 msec, and K
1, 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 calculation is performed by three-dimensional interpolation from the μ table shown in Table 2 using the vehicle body acceleration Vg.

[0020]

[Table 2]

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

In the flowchart of FIG. 3, when the absolute value of the current detected steering angle θ is equal to or greater than a predetermined value θo, 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, the steering angle Lateral acceleration G using the corresponding turning radius Ri
(S41 to S44), and when the above conditions are not satisfied, the lateral acceleration G is calculated using the actual turning radius Rr (S41 to S43, S45), and then the correction coefficient k based on the lateral acceleration G is calculated. (S46).

The lateral acceleration G is calculated from the vehicle speed V and the turning radius R (steering angle-corresponding turning radius Ri or actual turning radius Rr) by the following equation. G = V × V × (1 / R) × (1/127) (4) Next, in S46, the correction coefficient k based on the lateral acceleration G
Is calculated from the preset correction coefficient table in Table 3.

[0024]

[Table 3]

Next, in S4 of the flowchart of FIG. 2, a threshold value for slip determination is set. The threshold value for slip determination is set to a basic threshold value × a correction coefficient k, and the basic threshold value is a basic threshold value table 1 in Table 4 using the vehicle speed V and the road surface friction coefficient μ as parameters. Slip control start) or basic threshold table 2 in Table 5
(For continuation of slip control) is calculated by three-dimensional interpolation. The control target basic threshold value table 1 in Table 4 indicates whether or not to start slip control, and the control target basic threshold value table 2 in Table 5 indicates This is to determine whether or not the slip control should be continued.

[0026]

[Table 4]

[Table 5]

[0027]

[Table 6]

[Table 7]

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 apparent slip amounts SL and SR of the front wheels 2a and 2b as the left and right driving wheels are calculated from the wheel speeds Vha and Vhb of the left and right front wheels 2a and 2b. V is subtracted from each other to calculate (S51), and then it is determined whether or not the vehicle is turning based on the detected steering angle θ (S5).
2) When the vehicle is turning, S5 is determined in order to obtain the slip amount in consideration of the wheel speed difference between the inner front wheel and the outer front wheel during the turning.
At 3, the apparent slip amounts SL and SR are corrected. When turning left, SL changes to (SL + k1),
Further, SR is corrected to (SR-k2), and at the time of turning right, SL becomes (SL-k2) and SR becomes (SR-k2).
+ K1).

The k1 is a slip amount correction value preset in Table 6 using the actual turning radius Rr and the vehicle speed V as parameters. The k2 is a table using the actual turning radius Rr and the vehicle speed V as parameters. 7 is a slip amount correction value set in advance. The correction terms for the left and right driving wheels are k1 and k2.
Is different from the wheel speeds V1 and R1 of the left and right driven wheels (rear wheels).
This is because the higher wheel speed is used as the vehicle speed V (vehicle speed) without using the average of V2. As described above, since the slip amount correction values k1 and k2 are set using the actual turning radius Rr and the vehicle speed V as parameters, it is possible to perform a correction that does not temporally shift the actual turning behavior of the vehicle. it can.

After the correction processing of S53, the process proceeds to S54, and S
At 54, the weighted average slip amount SAv is calculated as follows. When turning left, SAv = [α × SL + β × SR] / (α + β) (5) When turning right, SAv = [α × SR + β × SL] / (α + β) (6) The above α and β are Related weighting factors, for example: For high μ road: α = 0.20, β = 0.80 For medium μ road: α = 0.35, β = 0.65 For low μ road: α = 0.50, β = 0.50

That is, when the vehicle is turning, on a high μ road, the inner drive wheels tend to float due to the turning lateral acceleration G, and the slip amount of the inner drive wheels becomes extremely large. However, the excessive slip amount is applied as it is. Therefore, when the control level of the slip control is set using the simple average value of the slip amount of the inner and outer drive wheels, the average output amount of the slip As described above, on a high μ road, a weighted average value to which a weight for reducing the weight of the slip amount of the inside drive wheel is added is used. Moreover, on a high μ road, there is a margin in the grip force of the outer driving wheel and the driven wheel, so that the steering stability is not impaired even if the engine output is suppressed less.

In the case of a low μ road, in consideration of the fact that the grip force of the wheels tends to be insufficient, the average slip amount SAv is calculated as the average slip amount SAv in order to secure the stability of running and maneuvering. Values were used. In the case of the middle μ road, the weighting coefficients α and β are set so as to have an intermediate value between the case of the high μ road and the case of the low μ road. next,
If the result of determination in S52 is that the vehicle is not turning, in S55, the average slip amount SAv is calculated as the simple average of the slip amounts of the left and right drive wheels (SL + SR) / 2. The process proceeds from S54 or S55 to S56, and in S56, 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 performed. In the slip determination, the following (7) based on the maximum slip amount SHi and the threshold value for slip determination.
When the equation is satisfied, it is determined that the slip control is necessary, and the slip flag SFL is set to 1.

SHi ≧ Slip Determination Threshold (7) In this case, the non-control state (CFL = 0) is determined as the slip determination threshold in step S134 of the flowchart in FIG. 5 showing the routine of S9. When the slip control is being performed (CFL = 1), the control target basic threshold for continuation in Table 5 is used. Is done.

[0035]

[Table 8]

[Table 9]

Next, in S7, it is determined whether or not the flag CFL = 1, and if CFL = 0 (the slip control is not being executed), the routine immediately returns. On the other hand, in S7, CFL
= 1 (during the execution of the slip control), S8
Move to. Next, a control target value T is set in S8. The control target value T is the front wheel 2a, with a target value as a slip amount of 2b, the control target basic value table of Table 8 and the vehicle speed V and the road surface friction coefficient number μ as a parameter 3
The control target basic value and the correction coefficient k obtained by the dimension complementation are calculated by the following equation. Control target value T = Control target basic value × k (8)

Next, a control level FC is calculated in S9. Regarding this control level FC, the deviation EN of the average slip amount SAv from the control target value T and the rate of change D thereof
The basic control level FCB is determined based on EN, and the basic control level FCB is set in the range of 0 to 15 in consideration of the feedback correction and the first correction of the previous value FC (k-1). In the initial correction, the change rate DSAv of the average slip amount SAv is initially 0.
(+5) until the first flag ST
Until FL becomes 0, it is (+2). The routine of S9 will be described with reference to the flowchart of FIG. First, in S131, the deviation EN and the deviation change rate DEN are calculated by the following equations (9) and (10), respectively. Deviation EN = SAv (k) -Control target value T (9) Deviation change rate DEN = DSAv = SAv (k) -SAv (k-1) (10)

Next, in S132, the basic control level FCB is calculated from the basic control level table shown in Table 9 based on the deviation EN and the deviation change rate DEN. Next, S
At 133, a feedback correction for adding the previous control level FC (k-1) to the current control level FC (k) is performed, then a slip control determination is performed at S134, and then a first slip control determination is performed at S135. Then, in S136, an initial correction amount for forcibly increasing the control level from when the slip of the front wheels 2a, 2b is first determined until the first slip determination is eliminated is calculated.

The routine for determining the slip control in 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 vehicle is in the non-braking state. When 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. I do. On the other hand, when No is determined in S140, in S142, it is provided in the slip control unit,
The count value t1 of the first counter that counts the duration of the signal of the slip flag SFL = 0 and the count of the second counter that counts the duration that FC ≦ 3 and DSAv ≦ 0.3g are satisfied The value t2 is read out and the count value t1 is 1000 msec or more (S143: Yes), or the count value t2 is 500
If it is longer than msec (S145: Yes), the control flag CFL is reset, and the routine goes to S135.

The routine for determining the first time slip control in S135 will be described with reference to the flowchart of FIG.
First, in S150, the current control flag CFL is set.
(K) = 1 and the previous control flag CFL (k-1) =
If these conditions are satisfied, it is determined in step S151 that the initial flag STFL is set, and the flow shifts to step S136. On the other hand, when No is determined 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 set. If the condition is satisfied, the initial flag STFL is reset in S153, and the flow shifts to S136.
When it is determined No in S150 and S152, the process proceeds to S136. In S136, based on the first flag STFL signal and the average slip amount change rate DSAv shown in Expression 9, STFL = 1 and DSAv
When <0, the first correction amount (+2) is determined. Next, S1
At 37, the previous value FC is added to the basic control level FCB.
The final control level FC (k) is set in the range of 0 to 15 by adding the feedback correction of (k-1) and the first correction when there is the first correction.

Next, in S10 of the flowchart of FIG. 2, a slip 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 a fuel cut. For the ignition timing, see FIG.
The retard amount according to the control level is determined and output based on the map shown in FIG. In this case, based on the map shown in FIG. 9, the maximum retard amount is limited in a region where the engine speed is high. As for the fuel cut, one of the patterns 0 to 12 in the fuel cut table of Table 10 is selected based on the control level FC. The pattern number increases as the control level FC increases. In addition, the mark x in Table 10 indicates a fuel cut. In this case, as shown in FIG. 10, the fuel cut is limited in a region where the engine speed is low.
Fuel cut prohibition conditions are set for each control level.

[0042]

[Table 10]

Next, the operation of the slip control will be described. As shown in the time chart of FIG. 11, the threshold value for starting the slip control is set to a relatively high threshold value Sh based on the basic threshold value table for starting. Even if it becomes high, the slip control is not started unless the threshold value Sh is exceeded. When the wheel speed of the drive wheel exceeds the threshold value Sh, the slip flag SF
When L is set and the brake is in the inoperative state, the control flag CFL and the initial flag STFL are set and slip control is started.

In the turning operation of the vehicle, when it is determined that the understeer tendency is strong, the lateral acceleration G of the vehicle is calculated using the turning radius Ri corresponding to the steering angle, but the turning radius Ri corresponding to the steering angle is the actual turning radius Rr. Smaller than the lateral acceleration G
Is large and the correction coefficient k is small, so that the start determination threshold value Sh is low. Therefore, the slip control is started early, and it is possible to suppress the excessive understeer tendency before the drive torque of the drive wheels is reduced early. on the other hand,
When the understeer tendency is not large, the actual turning radius Rr
Is used to calculate the lateral acceleration G, so that the threshold value for slip determination and the control target value T are set accurately in accordance with the actual lateral acceleration.

Here, in the straight running of the automobile, the maximum slip amount SHi is determined from the apparent slip amounts SL and SR of the left and right drive wheels, but during turning, the wheel speed of the outer wheel is higher than that of the inner wheel. growing. Accordingly, when the apparent slip amount of the outer wheel is based on the apparent slip amount, the maximum slip amount SHi may exceed the threshold value Sh.
In the present invention, since the slip amount obtained by subtracting the slip amount correction value k2 from the apparent slip amount of the outer wheel is used, it is possible to prevent the slip control from being started even though the actual slip amount is not large. be able to.

On the other hand, there is a slight delay in the actual turning behavior of the vehicle with respect to the change in the detected steering angle. Therefore, the slip amount correction value k1 is determined based on the ideal turning radius and the vehicle speed determined from the detected steering angle. , K2, the correction taking into account the wheel speed difference between the inner and outer driving wheels is executed earlier than the actual turning behavior of the vehicle. In the present invention,
Slip amount correction values k1, k based on actual turning radius and vehicle speed
In order to determine 2, it is possible to make a correction that is compatible with the actual turning behavior of the vehicle and that is free from time deviation.

The average slip amount SAv is calculated based on the slip amount obtained as described above, and the control target value T is calculated as follows.
It is set based on the vehicle speed V and the road surface friction coefficient μ. Then, a deviation E of the average slip amount SAv from the control target value T is calculated.
The basic control level FCB is set on the basis of N and the rate of change DEN of the deviation, and the control level FC is obtained by performing an initial correction on the basic control level FCB. The ignition timing control and the fuel injection restriction according to this control level are performed. Control is performed.

Here, the simple average value of the slip amounts of the left and right drive wheels is used as the average slip amount SAv during straight running, and the average slip amount SAv of the left and right drive wheels is used as the average slip amount SAv during turning. A weighted average value obtained by adding a weight related to the road surface μ to the slip amount of the outer driving wheel is used. In the case of a high μ road, the weight of the slip amount of the inner drive wheels is set small, so that the weighted average value is small, and the slip control level F is set.
Since C is reduced, the degree of suppression of the engine output is reduced, and the acceleration performance can be improved. In the case of a low μ road, since the simple average value of the slip amounts of the left and right driving wheels is used as the average slip amount SAv, the control level FC of the slip control is set to a large value, and the engine output is greatly suppressed, so that the steering stability is reduced. Nature can be secured.

The reason why the initial flag STFL becomes 0 is as follows.
A time when the maximum slip amount SHi is equal to or less than the slip control continuation determining threshold value Sc, the slip control at this point is temporarily stopped. Since the basic value of the continuation threshold value Sc is calculated from the continuation basic value table and set to a relatively low value, the slip can be surely converged.

Even if the higher driving wheel speed becomes equal to or lower than the continuation threshold value Sc, if the state does not continue for one second or longer, the control flag CFL is maintained in the set state,
With the suspension of the slip control, the wheel speed of the driving wheel increases again, and when it exceeds the continuation threshold Sc, the slip flag SFL is set again and the slip control is restarted. In this case, the first flag STFL is not set, and the first correction of the control level FC is not performed. Accordingly, the control level FC is initially set only at the basic control level based on the deviation EN and the deviation change rate DEN, and thereafter, a value obtained by adding the previous value to the basic control level by 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 more than one second continues, the control flag CFL
Is reset, and the one-cycle slip control ends.

Here, another embodiment in which a part of the above embodiment is changed will be described. The control target basic values shown in Table 8 are
In the case where the road is set to the high μ road standard, weighting is applied to increase the weight of the slip amount of the inner drive wheels to the slip amount of the inner and outer drive wheels as the average slip amount SAv in order to secure stability during turning. Is preferably used. In this case, S5 in FIG.
For example, the weighting coefficients α and β of 4 are as follows. On a high μ road: α = 0.60, β = 0.40 On a medium μ road: α = 0.65, β = 0.35 On a low μ road: α = 0.70, β = 0.30 Note that the weighting factors α and β are the vehicle speed. V and road surface μ may be set as parameters in a table in advance, and the weighting coefficients α and β may be read from the table.

[Brief description of the 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 the step S3 in FIG. 2;

FIG. 4 is a flowchart of step S5 in FIG. 2;

FIG. 5 is a flowchart of step S9 in FIG. 2;

FIG. 6 is a flowchart of a slip control determination in S134 of FIG. 5;

FIG. 7 is a flowchart of an initial slip control determination in S135 of FIG. 5;

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 an ignition retard amount with respect to an 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 overall operation time chart of the slip control.

[Explanation of symbols]

 Reference Signs List 4 engine 8 control device 9a, 9b, 9c, 9d wheel speed sensor 10 steering angle sensor SAv average slip amount α, β weighting factor FC control level FCB basic control level Sh threshold for starting slip control Sc threshold for continuing slip control value

Continuation of the front page (56) References JP-A-1-257654 (JP, A) JP-A-4-314637 (JP, A) JP-A-5-139275 (JP, A) JP-A-4-232350 (JP) , A) JP-A-2-70563 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 29/00-29/06 F02D 41/00-45/00 395 B60K 41 / 00-41/28

Claims (3)

(57) [Claims] 1. A vehicle slip control device for performing traction control for suppressing slip of a drive wheel with respect to a road surface by suppressing an output of an engine, comprising: wheel speed detection means for detecting wheel speeds of four wheels of the vehicle; A slip amount calculating means for receiving the output of the wheel speed detecting means to determine a slip amount of the left and right driving wheels; a target value setting means for setting a target value of the slip amount according to a traveling state of the vehicle; In response to the output of the means, the average value of the slip amount of the left and right drive wheels is obtained, and the control amount of the traction control during straight running is determined based on the difference between the average value and the target value obtained by the target value setting means. A first control amount setting means for determining; a road surface μ detecting means for detecting a friction state of a road surface; an output of the slip amount calculating means and a road surface μ detecting means; As a value, a weighted average value obtained by adding a weight related to the road surface μ to the slip amount of the left and right driving wheels is obtained, and a turning average is calculated based on a difference between the weighted average value and the target value obtained by the target value setting means. And a second control amount setting means for obtaining a control amount of the traction control of the vehicle. 2. The control device according to claim 1, wherein the second control amount setting unit is configured to drive left and right.
When obtaining the average value of the slip amount of the wheel, when the road surface friction state high μ, the outer drive weights slip amount of inner drive wheel
2. The vehicle slip control device according to claim 1, wherein a weight that decreases the weight of the slip amount of the driving wheel is added. 3. The control device according to claim 2, wherein the second control amount setting unit is configured to drive left and right.
When calculating the average value of the slip amount of the wheels, the weight of the slip amount of the inner drive wheel is larger than the weight of the slip amount of the outer drive wheel regardless of whether the road surface friction state is high μ or low μ. The vehicle slip control device according to claim 1, wherein the vehicle slip control device is configured to add the following.