JP3279669B2 - 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 an improved slip control when a spare wheel is mounted.

[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. A traction control technique configured to control the engine output and the application of the braking force to the wheels (reduce the engine output or increase the braking force) so as to reach the target value is generally put to practical use. Not a few devices include a control device and a traction control device (for example, see Japanese Patent Application Laid-Open No. 1-197160).

[0003] By the way, when a tire of a wheel is punctured, the vehicle usually travels provisionally with spare wheels mounted thereon, but since the diameter of the spare wheels is slightly smaller, the slip amount of the spare wheels tends to increase. . Japanese Patent Application Laid-Open No. 1-145236 discloses that when the driving wheel speed and the vehicle speed in the steady running state are not equal to each other due to the mounting of the spare wheel or the decrease of the tire air pressure, the driving wheel A vehicle driving force control device is described in which a correction coefficient for making the speed equal to the vehicle speed is determined, and slip control is performed while performing a correction process using the correction coefficient.

[0004]

Since the rolling friction coefficient of the wheels varies according to the vehicle speed, the slip ratio also varies according to the vehicle speed. In this case, since the correction coefficient is set based on the driving wheel speed and the vehicle body speed in the steady traveling state at the first speed, an appropriate correction coefficient from low to high speed is not always obtained, and an appropriate slip coefficient is obtained. Control is not always possible. SUMMARY OF THE INVENTION It is an object of the present invention to provide a slip control device for a vehicle, in which when a spare wheel is mounted on a drive wheel, it is possible to prevent the driving force from being excessively suppressed by inappropriate slip control, and a spare wheel is mounted on a driven wheel. Sometimes, it is necessary to perform appropriate slip control.

[0005]

According to a first aspect of the present invention, there is provided a vehicle slip control device which receives an output from a wheel speed detecting means for detecting wheel speeds of a driving wheel and a driven wheel, respectively, and drives a pair of driving wheels on average. A speed calculating means for determining a wheel speed and a vehicle speed, and receiving the output of the speed calculating means, based on the average drive wheel speed and the vehicle speed, when the slip amount of the drive wheel relative to the road surface exceeds a predetermined threshold value, A slip control device for controlling the driving of the drive wheels to a target value, the slip control device comprising: a determination unit that determines whether or not a spare wheel is mounted on the drive wheel and the driven wheel. The slip control means is provided with a correction means for correcting the target value of the slip amount to be higher than the actual slip amount when one of the drive wheels is equipped with a spare wheel in response to the determination result of the determination means. wherein the speed calculation hand Receives the discrimination results of the discrimination means
Therefore, when a spare wheel is attached to one of the driven wheels,
The vehicle speed is determined based on the wheel speed of the
It is configured to seek.

[0006]

According to a second aspect of the present invention, a slip control device for a vehicle is provided such that the slip amount becomes a target value when the slip amount of the drive wheel relative to the road surface exceeds a predetermined threshold value based on the drive wheel speed and the vehicle body speed. A slip control device for a vehicle, comprising: a slip control unit configured to control driving of a drive wheel; and a determination unit configured to determine whether a spare wheel is mounted on the drive wheel and the driven wheel, wherein the slip control unit includes: When the spare wheel is mounted on one of the drive wheels in response to the result of the determination by the determining means, the drive wheel speed is determined based on the wheel speed of the drive wheel without the spare wheel. It is.

According to a third aspect of the present invention, there is provided the vehicle slip control device according to the second aspect , wherein the slip control means receives a determination result of the determination means and mounts a spare wheel on one of the driven wheels. The vehicle speed is determined based on the wheel speed of a driven wheel on which no spare wheel is mounted. According to a fourth aspect of the present invention, the vehicle slip control device controls 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 based on the drive wheel speed and the vehicle body speed. A slip control unit for controlling driving, wherein the slip control unit includes an average driving wheel speed of a pair of driving wheels even when a spare wheel is mounted on one of the driving wheels. The target value or the diameter of the spare wheel is set in advance so as to be lower than the target value.

[0009]

In the vehicle slip control device according to the first aspect, the speed calculating means receives an output from the wheel speed detecting means and calculates an average driving wheel speed and a vehicle body speed of a pair of driving wheels. The slip control means controls driving of the drive wheels based on the average driving wheel speed and the vehicle body speed such that the slip amount becomes a target value when the slip amount exceeds a predetermined threshold value. The determining means determines whether or not a spare wheel is mounted on the driving wheel and the driven wheel, and the correcting means provided in the slip control means determines whether or not the spare wheel is mounted on one of the driving wheels. The target value of the amount is corrected to be higher than the actual slip amount. Therefore, when the spare wheel is mounted on one of the drive wheels, the target value of the slip amount is corrected to be higher than the actual slip amount, and thus the control for reducing the driving force for reducing the slip amount is not executed. In addition, it is possible to prevent the driving force from being reduced due to improper slip control. And before
The speed calculating means is driven by the
If one of the wheels is equipped with a spare wheel,
To determine the vehicle speed based on the speed of the non-wearing driven wheels.
The effect of the spare wheels does not appear on the vehicle speed,
Slip control can be performed.

[0010]

According to a second aspect of the present invention, when the slip amount of the drive wheel with respect to the road surface exceeds a predetermined threshold value based on the drive wheel speed and the vehicle speed, the slip amount is controlled by the slip control means. The driving of the driving wheels is controlled so as to reach the target value. The discriminating means discriminates whether or not a spare wheel is mounted on the driving wheel and the driven wheel, and the slip control means receives the discrimination result of the discriminating means and mounts the spare wheel on one of the driving wheels. In some cases, the drive wheel speed is obtained based on the wheel speed of the drive wheel on which the spare wheel is not mounted. Therefore, the drive wheel speed is obtained without using the wheel speed of the drive wheel on which the spare wheel is mounted, and the slip amount is obtained, so that it is possible to execute substantially appropriate slip control without being affected by the spare wheel. it can.

According to a third aspect of the present invention, in the vehicle slip control device according to the second aspect , the slip control means has a spare wheel mounted on one of the driven wheels in response to a result of the determination by the determination means. In some cases, the vehicle speed is obtained based on the wheel speed of a driven wheel having no spare wheel. Therefore, it is possible to perform the vehicle speed influence of the spare wheel table Lena damage, the proper slip control. In the slip control device for a vehicle according to claim 4, the slip control means has an average driving wheel speed of a pair of driving wheels lower than a target value even when a spare wheel is mounted on one of the driving wheels. As described above, since the target value or the diameter of the spare wheel is set in advance, even when the spare wheel is mounted on one of the drive wheels, the control for reducing the driving force for reducing the slip amount is not executed, It is possible to prevent the driving force from being reduced by inappropriate slip control.

[0013]

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 of the vehicle.
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. Further, as sensors, a throttle opening sensor for detecting a throttle opening of the engine 4, an engine speed sensor for detecting a rotation speed of the engine 4, a steering angle sensor 10 for detecting a steering angle of a steering wheel, the four wheels 2a, A brake sensor for detecting a braking state of the four wheels 2a, 2a, 3b;
a, wheel speed sensors 9a, 9b for detecting wheel speeds of 3b,
9 c, 9 d, etc. are provided, and detection signals from these sensors are supplied to the control device 8.

The controller 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 determined by using a detection signal 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. After that, calculation of slip amount, determination of slip, setting of control target value T (target value of slip amount), calculation of control level FC for adjusting engine output, and the like are executed to control fuel control and ignition timing control. Outputs a control signal for slip control. Further, as a characteristic configuration of the slip control of the present application, it is determined whether or not a spare wheel (a tire smaller in diameter than a normal tire) is mounted on a drive wheel (front wheels 2a, 2b) and a driven wheel (rear wheels 3a, 3b). Discriminate and drive 1
When one of the driven wheels is mounted on a spare wheel, the control target value T is corrected to be higher than the actual slip amount. The vehicle speed V is determined based on the wheel speed.

Hereinafter, a flowchart of the slip control executed in the slip control unit will be described with reference to FIGS. However, the reference symbol Si (i = 1, 2, 3,
・ ・) Indicates each step. When the engine 4 is started, the slip control is started, and various detection signals are read from the sensors (S1). Next, in S2, the front wheels 2 are controlled based on the outputs of the wheel speed sensors 9a to 9d.
The wheel speeds V2a and V2b of the wheels a and 2b and the wheel speeds V3a and V3b of the rear wheels 3a and 3b are calculated. Next, in S3, it is determined whether or not the spare wheel is mounted and to which wheel the spare wheel is mounted. The preliminary wheel determination is performed, and this S3 will be described with reference to FIG.

In FIG. 3, in S31, the steering angle sensor 1
Based on the output from 0 and the output from the throttle opening sensor, it is determined whether or not the vehicle is traveling straight and traveling normally (constant speed traveling). If No, the process proceeds to S4, and if Yes, the process proceeds to S4.
Move to 32. When traveling straight and traveling steady,
Since there is no speed difference between the driving wheel speed and the driven wheel speed, the mounting of the spare wheel can be detected by comparing the wheel speeds. That is, in S32, (V2a + V3b) / (V2b
+ V3a) ≧ (1 + α). Where α is 0
<Α <1 is a predetermined value, and the wheel speed increases because the slip ratio increases when the spare wheel is mounted. When the determination is Yes, the spare wheel is mounted on the front wheel 2a or the rear wheel 3b. In this case, it is determined in step S33 whether V2a / V3b ≧ (1 + β).

Here, β is a predetermined value of 0 <β <1 and S
When the determination in Step 33 is Yes, the flag F2a is set assuming that the spare wheel is mounted on the front wheel 2a (S3).
4) If the determination in S33 is No, it is determined in S35 whether V3b / V2a ≧ (1 + γ). Here, γ is a predetermined value of 0 <γ <1, and the determination in S35 is Y
In the case of es, the flag F3b is set assuming that the spare wheel is mounted on the rear wheel 3b (S36). In this case, the vehicle speed is calculated based on only the wheel speed V3a without using the wheel speed V3b in the calculation of the vehicle speed V. In order to obtain V, the value of the wheel speed V3a is given to the wheel speed V3b obtained in S2 (S3
7). If the result of determination in S35 is No, the process proceeds to S4.
Then , the process proceeds from S37 to S4.

If the determination in S32 is No, the wheel speed V2
b and V3a are determined in the same manner as described above (S38 to S3).
40), when V2b / V3a ≧ (1 + β), the front wheel 2b
The flag F2b is set as a spare wheel is mounted on the rear wheel 3a (S39). If V3a / V2b ≧ (1 + γ), the flag F3a is set as a spare wheel is mounted on the rear wheel 3a (S39). S41) In this case, to calculate the vehicle speed V based on only the wheel speed V3b without using the wheel speed V3a in the calculation of the vehicle speed V, the wheel speed V3 determined in S2 is used.
The value of the wheel speed V3b is given to a (S42). Note that S
If the result of determination in step 40 is No, the process moves to S4, and
The process moves from S42 to S4.

Next, in S4, an operation for calculating the actual turning radius Rr, 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 equal to the value of the driven wheel 3
Calculated by Equation 1 using the wheel speeds V3a, V3b of a, 3b. Td is the tread of the vehicle (for example, 1.7
m).

[0022]

Rr = Min (V3a, V3b) × Tdｂ | V
3a-V3b | + 0.5Td The turning radius corresponding to the steering angle Ri substantially corresponds to the turning radius in the neutral steering, and 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.

[0023]

[Table 1]

The vehicle speed V is determined as the higher one of the wheel speeds V3a and V3b of the driven wheels 3a and 3b. The road friction coefficient μ is calculated based on the vehicle speed V and the acceleration Vg. In calculating the road friction coefficient μ,
Using a timer of 100 msec count and a timer of 500 msec count, from the start of the slip control to the lapse of 500 msec at which the vehicle body acceleration Vg does not become sufficiently large, the vehicle body acceleration Vg is calculated from the change of the vehicle speed V for 100 msec every 100 msec by the following formula 2. Asked,
After a lapse of 500 msec when the body acceleration Vg becomes sufficiently large, the vehicle speed V between 500 msec every 100 msec
The vehicle acceleration Vg is determined from the following equation (3).
V (k) is at present, V (k-100) is 100 ms
Before ec, V (k-500) is the vehicle speed before 500 msec, and K1 and K2 are predetermined constants.

[0025]

Vg = K1 × [V (k) -V (k-100)]

## EQU3 ## Vg = K2 × [V (k) -V (k-500)] The road surface friction coefficient .mu.
The calculation is performed by three-dimensional interpolation from the μ table shown in Table 2 using the vehicle body acceleration Vg.

[0026]

[Table 2]

Next, in step S5, the lateral acceleration G and the lateral acceleration corresponding 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. 4, 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, the turning corresponding to the steering angle is performed. The lateral acceleration G is calculated by using the radius Ri (S51 to S54). When the above conditions are not satisfied, the lateral acceleration G is calculated by using the actual turning radius Rr (S51 to S53, S55). Then, a correction coefficient k based on is calculated (S56).

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

G = V × V × (1 / R) × (1/127) Next, in S56, a correction coefficient k based on the lateral acceleration G is calculated.
Is calculated from the preset correction coefficient table in Table 3.

[0030]

[Table 3]

Next, in S6 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.

[0032]

[Table 4]

[Table 5]

Next, in S7, the calculation of the slip amount is executed. The calculation of the slip amount will be described with reference to the flowchart of FIG.
Is calculated by subtracting the vehicle speed V from the wheel speeds V2a and V2b of the left and right front wheels 2a and 2b (S71), and then the average slip amount SAv is calculated from the average value of the slip amounts SL and SR. Then, the maximum slip amount SHi is calculated from the higher value of the slip amounts SL and SR (S73). Next, in S8, a slip determination is performed. In the slip determination, when the following equation 6 is satisfied based on the maximum slip amount SHi and the slip determination threshold value, it is determined that the slip control is necessary, and the slip flag SFL is set to 1.

[0034]

Shi ≧ Slip Determination Threshold In this case, the non-control state (CFL = 0) is determined as the slip determination threshold in step S134 of the flowchart of FIG. 6 showing the routine of S13. When it is determined that the slip control is being performed (CFL = 1), the control target basic threshold value for continuation in Table 5 is used. You.

[0035]

[Table 6]

[Table 7]

Next, a control target value T is set in S9. The control target value T is a target value as the slip amount of the front wheels 2a and 2b. The control target basic value obtained by three-dimensional interpolation from the control target basic value table of Table 6 using the vehicle speed V and the road friction coefficient μ as parameters. It is calculated from the value and the correction coefficient k by the following equation.

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

In steps S10 to S13, as shown in FIG. 12, when the spare wheel is mounted on one of the front wheels 2a, 2b, which is the driving wheel, the control target value T is set to a value higher than the actual slip amount as shown in FIG. This is a step for correcting the value. In S10, it is determined whether or not the flag F2a or F2b is set. If No, the process proceeds to S13 and Ye
In the case of s, in S11, the control target value T ≧ 0.5 × (V
2a + V2b) -V, that is, it is determined whether the control target value T is equal to or more than the actual slip amount.
Then, if No, the actual slip amount [0.5 × (V2a + V2b) -V] is added to the control target value T in S12.
The process proceeds to S13.

As described above, when the spare wheel is mounted on one of the drive wheels, the control target value T is maintained to be equal to or more than the actual slip amount. Therefore, a control signal for suppressing the driving force of the driving wheels is not output, and the slip control is not substantially executed. As a result, it is possible to suppress the driving force by inappropriate slip control and prevent the output from lowering.

Next, a control level FC is calculated in S13. For the control level FC, a 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 a feedback correction of the previous value FC (K-1) is performed. And the first correction is taken into account, and set in the range of 0 to 15. This S13
This routine will be described with reference to the flowchart of FIG. 6. In S131, the deviation EN and the deviation change rate DEN are calculated by the following equation.

## EQU8 ## Deviation EN = SAv (K) -Control target value T

## EQU9 ## Deviation change rate DEN = DSAv = SAv (K)-
SAv (K-1)

Next, in S132, the basic control level FCB is calculated from the basic control level table shown in Table 7 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.

FIG. 7 shows an equivalent circuit of the slip control determination in S134. In FIG. 7, the AND circuit 68 outputs a set signal to the flip-flop 69 when the slip flag SFL = 1 and the brake is not applied. , AN
The D circuit 70 outputs “1” when FC ≦ 3 and DSAv ≦ 0.3 g. The OR circuit 71 outputs the signal of the slip flag SFL = 0 to the signal
The output signal “1” is received for 500 msec from the AND circuit 70 through the counter 73.
If c is received continuously, a reset signal is output to the flip-flop 69. Upon receiving the set signal, the flip-flop 69 outputs a signal of control flag CFL = 1 (during slip control).

FIG. 8 shows an equivalent circuit for the initial slip control determination in S135. 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, a reset signal is output to the flip-flop 75. The flip-flop 75 receives the set signal and receives the first flag STFL = 1.
(Initial control) is output. In S136,
When STFL = 1 and DSAv <0, an initial correction amount (+2) is determined based on the initial flag STFL signal and the average slip amount change rate DSAv shown in Expression 9. Next, in S137, the final correction level FC is calculated by adding the first correction amount to the feedback-corrected control level FC.

Next, in S14 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. Regarding 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. 10, the maximum retard amount is limited in a region where the engine speed is high. For fuel cut,
Based on the control level FC, one of the patterns 0 to 12 in the fuel cut table of Table 8 is selected. The pattern number increases as the control level FC increases. Note that the crosses in Table 8 indicate fuel cuts. In this case, as shown in FIG. 11, a fuel cut prohibition condition is set for each control level so that the fuel cut is restricted in a region where the engine speed is low.

[0044]

[Table 8]

The operation of the slip control described above will be described with reference to the time chart of FIG. 13. The slip control start threshold value Sh for shifting from the non-control state to the slip control has a basic value. It is calculated from the starting basic target value table in Table 4 and set to a relatively high threshold value. Therefore, even if the wheel speed of the drive wheel becomes high (the maximum slip amount SHi becomes large) due to disturbance or the like, the slip flag SFL is not set unless the start threshold value Sh is exceeded, and the slip control is not started. When the wheel speed of the drive wheel 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 CFL and the initial flag STFL are set and slip control is started. Become.

Further, in turning the vehicle, the steering angle θ
from the values of h and the vehicle speed V and the road surface friction coefficient mu, greater tendency to deviate from the running line in the steering angle corresponding turning radius Ri (e.g., Anne Da steering tendency is large) the steering angle corresponding turning radius Ri when it is determined that Is used to calculate the lateral acceleration G of the vehicle. In this case, the turning radius corresponding to the steering angle Ri is the actual turning radius R.
Since r is smaller than r, the required lateral acceleration G increases, and the correction coefficient k decreases, so that the slip control start threshold Sh decreases. Therefore, even if the slip amount itself is not so large, the slip control is started early, and this can be suppressed before an excessive understeering tendency occurs due to an early decrease in the driving torque of the driving 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 determined.
The control target value T is calculated based on the above equation, and the deviation EN of the average slip amount SAv from the control target value T and the rate of change DEN are determined.
Then, based on these, a control level FC taking into account the initial correction is obtained, and the ignition timing and the fuel injection restriction corresponding to the control level FC are executed. The initial correction is (+5) until the change rate DSAv of the average slip amount SAv first becomes 0, and (+2) until the initial flag STFL becomes 0. The control amount is forcibly increased by this initial correction, and the early convergence of the slip can be achieved.

The reason why the first flag STFL becomes 0 is as follows.
This is the point in time when the maximum slip amount SHi due to the higher drive wheel speed becomes equal to or less than the threshold value Sc for continuation determination of the slip control. Therefore, when it is determined that the tendency to deviate from the travel line at the steering angle-corresponding turning radius Ri during turning is large, the correction coefficient k becomes small, so that the control target value T becomes small, and the slip amount is reduced to this target value. As a result, the amount of reduction in the drive torque of the drive wheels increases, and the understeering tendency can be eliminated at an early stage. The continuation determination threshold value Sc is set to a relatively low threshold value by calculating its basic value from a continuation basic value table. In addition, the turning radius corresponding to the steering angle R
When it is determined that the tendency to deviate from the travel line at i is large, the correction coefficient k becomes small, so that the continuation determination threshold value Sc becomes further lower, and the control can be continued until the slip reliably converges. .

On the other hand, when the tendency to deviate from the travel line at the turning radius Ri corresponding to the steering angle is not large, the actual turning radius Rr
Is used to calculate the lateral acceleration G, so that the slip determination threshold value and the control target value T are accurately corrected to match the actual lateral acceleration. Even if the higher drive wheel speed becomes equal to or lower than the continuation determination threshold value Sc, the state remains for 1 second or more.
Continued or otherwise if the control flag CFL is maintained in the set state. Then, as the reduction amount of the drive wheel drive torque decreases, the drive wheel speed increases again, and when the drive wheel speed exceeds the continuation determination 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 initially includes the deviation EN and the deviation change rate D.
Only the basic control level based on EN is set, and thereafter, the value obtained by adding the previous value to the basic control level by feedback correction is set as the control level FC. 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 becomes 0 and the slip control ends.

As a characteristic configuration of the slip control, it is determined whether or not a spare wheel is mounted on a driving wheel and a driven wheel.
In addition, a wheel on which a spare wheel is mounted is determined. If a spare wheel is mounted on one of the front wheels 2a, 2b, which is a drive wheel, a control target value T which is a target value of a slip amount of the drive wheel. Is configured to maintain the actual slip amount or more, so that it is possible to surely prevent the output from being reduced by suppressing the driving force by inappropriate slip control in a state where the drive wheel speed cannot be reliably obtained. Can be. Further, when a spare wheel is mounted on one of the rear wheels 3a and 3b that are driven wheels,
Since the vehicle speed V is obtained by using only the wheel speed of the driven wheel without the spare wheel, without using the wheel speed of the driven wheel with the spare wheel, the appropriate slip Control can be performed.

Next, a modification in which a part of the above embodiment is changed will be described with reference to FIG. In this modification, when a spare wheel is mounted on one of the driving wheels, the driving wheel speed is obtained without using the wheel speed of the driving wheel.
When a spare wheel is mounted, the vehicle speed is obtained without using the wheel speed of the driven wheel. That is, S10 to S1 in FIG.
Step 2 is omitted, and as shown in FIG. 14, steps S43 and S44 are added to the routine of FIG.
When the spare wheel is mounted on the left front wheel 2a, after setting the flag F2a in S34, the wheel speed V2a of the right front wheel 2b without the spare wheel is given to the wheel speed V2a in the next S43. Similarly, when the spare wheel is mounted on the right front wheel 2b, after setting the flag F2b in S39, the wheel speed V2b is given the wheel speed V2a of the left front wheel 2a without the spare wheel in the next S44. . The configuration other than the above is the same as that of the above-described embodiment, and thus the description is omitted. In this way, the wheel speed of the drive wheel on which the spare wheel is mounted is given to the wheel speed of the drive wheel on which the other spare wheel is not mounted, and the wheel speed of the drive wheel on which the spare wheel is mounted. By giving the wheel speed of the driven wheel the wheel speed of the driven wheel on which the other spare wheel is not mounted, it is possible to perform substantially appropriate slip control excluding the influence of the spare wheel.

Next, another modified example in which a part of the above embodiment is changed will be described. In the flowchart of FIG. 2, the determination result of S11 is always set to Yes, that is, even when the spare wheel is mounted on one of the drive wheels,
The target value T or the diameter of the spare wheel is set in advance so that the target value T of the slip amount is higher than the average driving wheel speed of the pair of left and right driving wheels. In this case, each value of the target basic value table of Table 6 is set to be sufficiently large, or each value of the target basic value table of Table 6 is not changed, and the value is equal to or larger than the diameter set as described above. Spare wheels. As a result, the same operation as the above embodiment can be obtained.

[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 a routine of step S3 in FIG. 2;

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

FIG. 5 is a flowchart of a routine of step S7 in FIG. 2;

FIG. 6 is a flowchart of a routine of step S13 in FIG. 2;

FIG. 7 is an equivalent circuit diagram of the step of S134 in FIG. 6;

FIG. 8 is an equivalent circuit diagram of the step of S135 in FIG. 6;

FIG. 9 is a diagram of a map of an ignition retard amount with respect to a control level.

FIG. 10 is a diagram of a map of an ignition retard amount with respect to an engine speed;

FIG. 11 is an explanatory diagram of a fuel cut prohibition region with respect to a control level and an engine speed.

FIG. 12 is a time chart showing a relationship between a vehicle speed, a control target, an average force of drive wheel speeds, and the like.

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

FIG. 14 is a diagram corresponding to FIG. 3 according to a modification.

[Explanation of symbols]

 2a, 2b Front wheel (drive wheel) 3a, 3b Rear wheel (driven wheel) 4 Engine 8 Control device 9a, 9b, 9c, 9d Wheel speed sensor FC control level FCB basic control level Sh Slip control start threshold Sc Slip control Continuity determination thresholds V2a, V2b Wheel speeds of driving wheels 2a, 2b V3a, V3b Wheel speeds of driven wheels 3a, 3b V Vehicle speed (body speed) T Control target value

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 29/02 311 B60K 41/00 F02D 41/00-45/00

Claims (4)

(57) [Claims] A speed calculating means for receiving an output from a wheel speed detecting means for detecting a wheel speed of each of a driving wheel and a driven wheel to obtain an average driving wheel speed and a vehicle body speed of a pair of driving wheels; Control based on the average drive wheel speed and the vehicle speed, and controls 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. Means for determining whether or not a spare wheel is mounted on the driving wheel and the driven wheel, wherein the slip control means receives a result of the determination by the determining means. When one of the drive wheels is equipped with a spare wheel , the speed calculating means includes a correcting means for correcting the target value of the slip amount to be higher than or equal to the actual slip amount. And obey
When a spare wheel is attached to one of the driving wheels,
Calculate the vehicle speed based on the wheel speed of the non-equipped driven wheel
A vehicle slip control device characterized by being configured as described above . 2. A slip control for controlling driving of a drive wheel based on the drive wheel speed and the vehicle body speed such that the slip amount becomes a target value when the slip amount of the drive wheel relative to a road surface exceeds a predetermined threshold value. Means for determining whether or not a spare wheel is mounted on the drive wheel and the driven wheel, wherein the slip control means receives a determination result of the determination means, A slip control device for a vehicle, wherein when a spare wheel is mounted on one of the drive wheels, the drive wheel speed is determined based on the wheel speed of the drive wheel without the spare wheel. . 3. The slip control device for a vehicle according to claim 2 , wherein the slip control means mounts a spare wheel when one of the driven wheels is mounted with a spare wheel in response to a result of the determination by the determining means. A vehicle slip control device configured to determine a vehicle body speed based on a wheel speed of a driven wheel that has not been driven. 4. A slip control for controlling the driving of the drive wheels based on the drive wheel speed and the vehicle body speed such that the slip amount becomes a target value when the slip amount of the drive wheel relative to the road surface exceeds a predetermined threshold value. And a slip control means, wherein the slip control means has an average drive wheel speed of a pair of drive wheels lower than the target value even when a spare wheel is mounted on one of the drive wheels. A slip control device for a vehicle, wherein a target value or a diameter of a spare wheel is set in advance so as to be set.