JP3278449B2 - Anti-skid 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 an anti-skid control device that operates when a vehicle is braked.

[0002]

2. Description of the Related Art Generally, when a vehicle is braked, a descending slope of a vehicle body speed does not coincide with a descending curve of a wheel speed.
Depending on the braking conditions at that time, the wheel speed drops greatly and the deceleration increases, and finally the wheels are locked. Therefore, when a drop in wheel speed equal to or greater than a certain reference value is detected after the application of the brake, the anti-skid control device operates to gradually reduce the brake oil pressure applied to the wheel in order to prevent the wheel from locking. Go. When the wheel speed is restored by the pressure reduction, the brake oil pressure is once held at the current oil pressure, then the oil pressure is increased linearly, and then the pressure is increased stepwise (pulse increase).

When a drop in the wheel speed exceeding a certain reference value is detected again, the brake oil pressure applied to the wheel is gradually reduced again, and when the wheel speed returns again, the brake oil pressure is reduced again. Holding, boosting,
Increase the pulse pressure. By repeating such a process, the wheel speed is lowered along a certain target value (for example, about 80% of the vehicle speed at that time), and the predetermined braking distance is prevented while the lock state is prevented. To stop the vehicle.

FIG. 3 shows the temporal change of the oil pressure (W / C pressure) in the wheel cylinder when the pressure reduction signal for performing the pressure reduction is output. As shown in FIG. As time elapses, the W
The / C pressure decreases, and the manner of the decrease is as the time elapses (that is, as the W / C pressure decreases).
Gradually slows down. Therefore, the time required to reduce the W / C pressure by the predetermined oil pressure amount ΔP when the W / C pressure is high is, for example, t ₁ , while the W / C pressure is reduced when the W / C pressure is low. Assuming that the time required to decrease by the same oil pressure amount ΔP is t ₂ , for example, t ₁ <t ₂ .

When a brake is applied while the vehicle is traveling on a high μ road surface (a road surface having a high friction coefficient), the W / C pressure (oil pressure of the wheel cylinder) increases. As shown in FIG. 3, the pressure reduction amount increases even if the pressure reduction signal is output for a short time. However, in this type of conventional control device, when it is determined that the friction coefficient μ of the road surface is high, since the basic depressurization time is fixed, when the depressurization amount is too large (that is, when the depressurization is excessive), Occurs, and in such a case, the vehicle body G
(Vehicle deceleration) fluctuates too much, and there is a problem that riding comfort is deteriorated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and excessively reduces the pressure (brake hydraulic pressure) generated when the brake is operated while traveling on a high μ road surface as described above. The body G
An appropriate decompression time is set so that large fluctuations can be suppressed.

[0007]

According to the present invention, there is provided an actuator which corresponds to each wheel of a vehicle.
Control the brake oil pressure applied to each wheel.
Outputting a pressure reduction signal to the actuator.
Anti-skid control to reduce the brake oil pressure
In the apparatus, means for detecting vehicle deceleration, Actuator
Within a predetermined time after outputting the pressure reduction signal to the eta
Means for detecting the amount of variation in all vehicle decelerations, and
An anti-skid control device is provided, which comprises means for changing the pressure reduction time of the brake oil pressure at the time of the next pressure reduction signal output in accordance with the amount of change. Furthermore, according to the present invention for solving the above problems, a sensor for detecting a vehicle deceleration in the longitudinal direction of the vehicle, the
After outputting the pressure reduction signal to the actuator,
Means for detecting the variation amount of the vehicle deceleration based on the output from the sensor within the time, the detected variable
Brake oil at the next output of pressure reduction signal according to the amount of movement
An anti-skid control device comprising means for changing a pressure reduction time is provided. According to one specific mode, the changing means sets the next decompression signal as the fluctuation amount of the detected vehicle deceleration is larger.
Decrease the brake pressure reduction time during output .

[0008]

According to the above construction, the amount of change in the vehicle deceleration (vehicle body G) due to the above-mentioned depressurized output is detected, and the decompression time at the next depressurized output is corrected in accordance with the detected amount of change. be able to. That is, when the vehicle body deceleration is equal to or greater than the predetermined value, the amount of decrease in the vehicle body deceleration within a predetermined time after the output of the pressure reduction is detected. When the vehicle is overexecuted), the basic depressurization time at the next lock (at the time of depressurization output) can be reduced to suppress a large fluctuation of the vehicle body G.

[0009]

FIG. 6 and FIG. 7 are flowcharts showing the general operation procedure of the anti-skid control device. That is, first, at the start of control, step 11 becomes no and step 12 becomes yes. As a result, at the start of the control, the pressure reduction mode is set in step 13. Next, if the control does not end in step 14, the process proceeds to step 15 and the mode is determined. (It is determined by the normal flag, and in this case, the depressurization mode is set.) If the control is not started in step 12 with no and the control is ended in step 14 with yes, the process proceeds to step 28, and Control.

As described above, if it is determined in step 15 that the mode is the decompression mode, the process proceeds to step 16, and until the decompression mode ends, the process proceeds to step 24 to output a reduced pressure.
The brake oil pressure is gradually reduced. And step 16
When the pressure-reducing mode is completed, the holding mode is set in step 17 and the process proceeds to step 18. Until the holding mode is completed, the process proceeds to step 25 where the holding output is performed, and the brake is held at a predetermined value. Oil pressure is output. At this time, step 11 is YES because control is being performed, and if control is not ended in step 14, the mode determination in step 15 is the hold mode.

When the holding mode is completed in step 18, the pressure increasing mode is set in step 19 and the process proceeds to step 20. Until the pressure increasing mode is completed, the process proceeds to step 26 and the pressure increasing output is performed. The brake hydraulic pressure is increased linearly. Also in this case, step 11 is YES because the control is being performed, and if the control does not end in step 14, the mode determination in step 15 is the pressure increase mode.

When the pressure increasing mode ends at step 20, the pulse pressure increasing mode is set at step 21 and proceeds to step 22. Until the pulse pressure increasing mode ends, the process proceeds to step 27 to increase the pulse increasing mode. A pressure output is made, and the brake oil pressure is increased stepwise. Also, at this time, step 11 is affirmative because the control is being performed.
The mode determination of 5 is the pulse pressure increasing mode.

When the pulse pressure increasing mode is completed in step 22, the pressure reducing mode is set again in step 23, and the program proceeds to step 24 where a reduced pressure output is performed.
Also at this time, step 11 is YES because control is being performed, and if control is not ended in step 14, the mode determination in step 15 is a depressurization mode. Each mode of pressure reduction → hold → pressure increase → pulse pressure increase → pressure reduction → ── is sequentially and repeatedly set. In this case, the time during which each of the modes (for example, the decompression mode) is set is determined according to the speed state of the wheel.

FIG. 5 is a system configuration diagram of this kind of anti-skid control device. When a brake pedal is depressed, brake oil filled in a master cylinder M / C is supplied to each wheel (left and right front wheels). Each F
L and FR, and the right and left rear wheels are RL and R, respectively.
Indicated by R. ) Wheel cylinder W provided opposite to
/ C to brake the wheels.
In this case, an actuator (ie, FL.ACT; FR.AC) corresponding to each wheel controlled by the ECU.
T; RL. ACT, and RR. ACT) changes the brake hydraulic pressure applied to each wheel. In the ECU, even if a failure occurs in one of the hydraulic systems from the wheel speed sensors WS1 to WS4 for the respective wheels, a brake is secured in the remaining hydraulic system. The output side of the master cylinder is divided into a side C1 for supplying hydraulic pressure to a pair of wheels FR and RL and a side C2 for supplying hydraulic pressure to the remaining pair of wheels FL and RR. Is entered.

FIG. 4 shows an example of a configuration applied to the present invention as the ECU in FIG. 5 described above. A CPU provided in the ECU includes acceleration (or deceleration) in the longitudinal direction of the vehicle. A sensor signal from a sensor (G sensor) AS for detecting the pressure is input via an A / D converter 11, and a signal from various switches (for example, a brake switch for confirming that the brake is depressed) is converted to a level conversion circuit 12. , And sensor signals from the wheel speed sensors WS1 to WS4 for the respective wheels are input via waveform shaping (pulse shaping) circuits 13 to 16, and a power supply circuit 17 for the CPU is input from the battery B to the CPU. Is done.

A motor relay MR is connected to the output side of the CPU through a motor relay drive circuit 21.
When the relay MR is turned on, the pump motor (motor for returning oil accumulated in the reservoir at the time of pressure reduction to the master cylinder M / C) PM is operated. Further, at the time of abnormality (for example, at the time of failure), the abnormality lamp L is operated through the lamp drive circuit 22. If there is no abnormality in the ECU, the solenoid relay SR is always turned on through the solenoid relay drive circuit 27. If the solenoid relay SR is turned on, the actuator (i.e., FR.
ACT; FL. ACT; RR. ACT; and RL. A
CT) is controlled by the CPU.

FIG. 1 is a flowchart showing one embodiment of a processing procedure of the anti-skid control device according to the present invention. When the detected vehicle deceleration is equal to or greater than a predetermined value, a pressure reduction output is generated. , The fluctuation amount (decrease amount) of the vehicle body deceleration within a predetermined time is detected, and when the detected decrease amount is equal to or more than a predetermined value (that is, the pressure is excessively reduced), the next pressure reduction output (at the next lock) Is corrected so as to be an appropriate value (that is, if the pressure is excessively reduced, the basic pressure reduction time at the next pressure reduction output is shortened).

That is, as shown in FIG. 1, the process starts in step 1 and in step 2, the acceleration sensor (G sensor) AS shown in FIG.
Is read into the CPU, and the vehicle body G read in step 3 is read.
Is greater than a predetermined vehicle body deceleration KG (for example, 0.6 G). If no, the process proceeds to step 4, where ΔT (the pressure reduction time at the next pressure reduction output) is set to 0.

On the other hand, if the determination in step 3 is YES, the process proceeds to step 5, where it is determined in the CPU whether or not the pressure reduction output is currently being performed. If the determination is yes, the process proceeds to step 6, in which the high peak value of the vehicle body G during the pressure reduction output is stored and held in the memory 1. At that time, in step 7, the count value of the counter CT is set as the value after the pressure reduction output. A predetermined value KT (for example, 100 milliseconds) corresponding to a predetermined time is set. And, during the pressure reduction output, the step 5
When the decompression output is completed, the determination in step 5 becomes no, and thereafter, the process proceeds to step 8 and the counter CT is executed at each calculation timing.
Are sequentially decremented by one.

Then, the program proceeds to a step 9, wherein it is determined whether or not the count value of the counter CT has become zero. In the case of knowing (within a predetermined time KT after the pressure reduction output), the process proceeds to step 10 and the low peak value of the vehicle body G during that time is stored in the memory 2. If the determination in step 9 is affirmative (when a predetermined time KT has elapsed after the pressure reduction output), the process proceeds to step 11 at that point and the memory 1
And the value of the difference between the high peak value and the low peak value of the vehicle body G stored and held in the memory 2 (that is, the vehicle deceleration at the time of pressure reduction output (the high peak value) until the predetermined time KT elapses after the pressure reduction output) The decrease amount reduced to the low peak value) is set as ΔG. Then, in step 12, it is determined whether or not the set vehicle body deceleration reduction amount ΔG is larger than a predetermined value (predetermined reduction amount) KΔG. According to such a map, the pressure reduction time ΔT at the time of the next pressure reduction output is selectively set. That is, as shown in FIG. 2, the reduction amount ΔG of the vehicle body deceleration
Is increased stepwise, the pressure reduction time ΔT is also set to be gradually increased, so that the basic pressure reduction time at the next pressure reduction output is shortened accordingly.

[0021]

According to the present invention, even when a brake operation is performed while traveling on a high μ road surface, the pressure is not excessively reduced, and an appropriate reduced pressure output can be obtained. Comfort can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a processing procedure of an anti-skid control device according to the present invention.

FIG. 2 is a diagram exemplifying a map used for selecting a decompression reduction time at the next decompression output according to a reduction amount of a vehicle body deceleration.

FIG. 3 is a diagram illustrating a temporal change of a W / C pressure at the time of outputting a pressure reduction signal;

FIG. 4 is a diagram showing an example of a configuration applied to the present invention as the ECU in FIG. 5;

FIG. 5 is a diagram illustrating a system configuration of an anti-skid control device.

FIG. 6 is a flowchart illustrating a general processing procedure of the anti-skid control device.

FIG. 7 is a flowchart illustrating a general processing procedure of the anti-skid control device.

[Explanation of symbols]

AS: acceleration sensor (G sensor) WS1 to WS4: wheel speed sensor M / C: master cylinder W / C: wheel cylinder FR, FL, RR, RL: front wheel and rear wheel FR. ACT; FL. ACT; RR. ACT; RL. ACT: Actuator corresponding to each wheel

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 8/72

Claims (3)

(57) [Claims] An actuator corresponding to each wheel of a vehicle
Controls the brake hydraulic pressure applied to each wheel.
And outputting a decompression signal to the actuator.
Anti-skid control device for reducing the brake oil pressure
In the above, after outputting the pressure reduction signal to the means for detecting the vehicle body deceleration and the actuator
Detecting a variation amount of the vehicle body deceleration within a predetermined time;
Means at the time of the next pressure reduction signal output according to the detected fluctuation amount.
An anti-skid control device comprising means for changing a pressure reduction time of a brake oil pressure in the anti-skid control device. 2. An actuator corresponding to each wheel of a vehicle.
Controls the brake hydraulic pressure applied to each wheel.
And outputting a decompression signal to the actuator.
Anti-skid control device for reducing the brake oil pressure
In a sensor for detecting a vehicle deceleration in the longitudinal direction of the vehicle, from the output of the pressure reduction signal to the actuator
Means for detecting a fluctuation amount of the vehicle body deceleration based on an output from the sensor within a predetermined time; and at the next pressure reduction signal output according to the detected fluctuation amount.
An anti-skid control device comprising means for changing a pressure reduction time of a brake oil pressure in the anti-skid control device. 3. The method according to claim 1, wherein the changing means outputs the next pressure reduction signal as the fluctuation amount of the detected vehicle deceleration increases.
3. The anti-skid control device according to claim 1, wherein the pressure reduction time of the brake oil pressure at the time is reduced.