JPH03211439A - Inspecting method for anti-lock brake system of vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for testing an anti-lock brake system of a vehicle.

(Prior Art) A generally used anti-lock brake system for automobiles uses a sensor to detect the vehicle's wheel speed, and a control unit using a microcomputer detects whether the wheels are about to lock based on the output of the wheel speed sensor. An actuator driven by the output of this control unit is configured to judge the state and control the brake oil pressure, and the braking force is appropriately weakened to prevent the wheels from locking during braking.

When inspecting a vehicle incorporating this type of anti-lock brake system, the function of the control unit has conventionally been investigated. Many devices are equipped with a self-diagnosis program in their control unit, and the unit itself checks whether the drive signal of the actuator changes correctly in response to changes in the output of the wheel speed sensor. was.

(Problem to be Solved by the Invention) As mentioned above, the inspection using the self-diagnosis program of the control unit only examines the signal processing function of the unit, and does not include all of the wheel speed sensors, actuators, brake hydraulic system, etc. The entire system was not inspected, and no abnormalities were found in any parts other than the unit.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to enable comprehensive inspection of the functions of an anti-lock brake system installed in a vehicle in a simple manner.

(Means for solving the problem of teaching assistance) The inspection method according to the present invention includes the following means.

(A) Rotate the wheels at a predetermined speed with a test roller and check whether the output of the wheel speed sensor of the anti-lock brake system is normal.

(B) Instead of the output of the wheel speed sensor, a separately generated pseudo wheel speed signal is input to the control unit of the antilock brake system.

(C) While the wheels are being rotated by the test roller, depress the brake pedal of the vehicle, and in that braking state, change the speed value of the pseudo wheel speed signal given to the control unit from a sufficiently large value. The braking force is then suddenly changed to almost zero, and the braking force before and after the change is measured.

(Function) In the process of (C) above, when the speed value of the pseudo wheel speed signal is sufficiently large, the control unit determines that the wheels are not locked and does not perform an output operation to reduce the brake hydraulic pressure. , the braking force measured at that time is sufficiently large. When the speed value of the pseudo wheel speed signal suddenly changes from a sufficiently large value to almost zero, the control unit determines that the wheels are likely to lock and performs an output operation to reduce the brake hydraulic pressure. , it can be measured that the braking force is weakened by that action.

(Example) Figure 1 shows an example of an anti-lock brake system to be inspected. This example is a simple system with an anti-lock function added only to the rear wheels. 1 is the brake pedal, 2
3 is a front wheel brake hydraulic circuit (not included in the anti-lock brake system), and 4 is a rear wheel brake hydraulic circuit. A hydraulic control valve 5 corresponding to the actuator is included in the rear wheel brake hydraulic circuit 4, and this valve 5 supplies brake hydraulic pressure of $11JII to the wheel cylinders 6a, 6b, of the rear wheels. Further, a wheel speed sensor 7 is added to the rear wheel differential gear, and the output signal of the sensor 7 is input to the control unit 8. Control unit 8 is wheel speed sensor 7
determines whether the rear wheels are likely to lock based on the output of
The hydraulic pressure control valve 5 is appropriately controlled to adjust the hydraulic pressure supplied to the rear wheel cylinders 6a, 6b.

FIG. 2 shows an outline of inspection equipment for carrying out the inspection method according to the present invention. Reference numeral 14 denotes a floor surface on which the vehicle to be inspected runs, and below the floor surface there is a braking force measuring device 9 equipped with a test roller 10.
An indicator 11 is arranged at the front upper part of the test vehicle. Further, a cable extending from the $(l board 13) is arranged above the test roller 10 via an indicator 11.
A check coupler 12 is attached to the tip of the cable.

The inspection will be carried out using the equipment shown in Figure 2 according to the following procedure.

(2) Drive the vehicle to be tested on the floor 14 and place the rear wheels on the test rollers 10.

Also, the cable of the check coupler 12 extending from the indicator 11 is stretched out and connected to a predetermined connector of the test vehicle. As a result, the wheel speed sensor 7 shown in FIG.

■The test roller 10 rotates the rear wheels of the vehicle at a predetermined speed, and the output of the wheel speed sensor 7 at that time is sent to the control panel 13.
Check to see if the sensor signal is normal.

Of course, if there is an abnormality, appropriate measures will be taken.

(2) A signal generator built into the indicator 11 generates a pseudo wheel speed signal, and the signal is input via the check coupler 12 to the control unit 8 of the test vehicle as a signal in place of the output of the sensor 7.

The speed value of the pseudo wheel speed signal at this time is set to a sufficiently large value, for example, 7 ohms per hour. At the same time, the rear wheels are rotated by the test roller 10, and an attendant sitting in the driver's seat of the test vehicle depresses the brake pedal 1 with a sufficiently large force and continues to depress it. Then, the braking force at this time is measured by the braking force measuring device 9, and the measured value is stored in the control panel 13.

(2) While maintaining the braking state and braking force measurement state of (2) above, the speed value of the pseudo wheel speed signal generated from the check coupler 12 is suddenly changed from 701 aw per hour to zero. Then, the change in braking force after this change is measured using the measurement device ft9.

When a pseudo wheel speed signal of 70 kjI is being applied, the control unit 8 determines that the rear wheels are not locked at all, and does not perform any control to lower the brake oil pressure of the rear wheels. Therefore, the braking force is sufficiently large.

When the pseudo wheel speed signal is set to zero during braking operation,
The control unit 8 determines that the wheels are locked, and the hydraulic control valve 5 reduces the brake hydraulic pressure for the rear wheels. The braking force measured by the measuring device 9 is therefore reduced. If this amount of decrease reaches a specified value, it is tentatively determined that the system is functioning normally. Further, if subsequent changes in braking force are continuously measured, if the system is normal, the braking force that once decreased will return to its initial value. Also check this change in braking force. If the above inspection results are normal, the test is complete, and the test roller 10 is stopped, the check cover 12 is removed from the vehicle connector and returned to its original state, the vehicle is driven to another position, and the next test is performed. Transport the vehicle to the test location.

(Effects of the Invention) As explained in detail above, in the inspection method of the present invention,
Depress the brake pedal while the wheels are actually rotating on the test roller, and then suddenly change the speed value of the pseudo wheel speed signal supplied to the control unit from a sufficiently large value to almost zero, and test each condition. Since the braking force is measured at the control unit, it is possible to perform a comprehensive inspection that includes not only the signal processing function of the control unit, but also the hydraulic system and mechanical system that actually generates the braking force, making it an extremely reliable inspection. In addition, the operation for inspection is very simple and is almost the same as a general brake inspection using a test roller.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of an anti-lock brake system to be inspected by the present invention, and FIG. 2 is a schematic diagram showing an outline of equipment for carrying out the inspection method of the present invention. 1...Brake pedal 2...Mask cylinder 3...Front wheel brake hydraulic circuit 4...Rear wheel brake hydraulic circuit 5...Hydraulic pressure control Valve 6a, 6b...Wheel cylinder 7...
・Wheel speed sensor 8... Control unit 9... Braking force measuring device 0... Test low-rad... Indicator 3... Control panel 12...Check cover 14...Floor surface

Claims (1)

[Claims] Means for checking whether the output of the wheel speed sensor of the anti-lock brake system is normal by rotating the wheel at a predetermined speed with a test roller; means for inputting a pseudo wheel speed signal to the control unit of the anti-lock brake system; depressing the brake pedal of the vehicle while the wheels are being rotated by the test roller, and inputting the pseudo wheel speed signal to the control unit in the braking state; A method for inspecting an anti-lock brake system of a vehicle, comprising means for suddenly changing the speed value of the pseudo wheel speed signal from a sufficiently large value to almost zero, and measuring the braking force before and after the change.