Motor vehicle brake antilocking system
AssigneeWABCO Westinghouse Fahrzeugbremsen GmbH
InventorHelmut Pannbacker
Life of this patent
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Abstract
An antilocking system is being proposed which does not generate unplanned control signals when axle oscillations occur. To this purpose, a threshold value stage 6 for the wheel deceleration signals (-b) has an increased threshold value. After separation of the wheel velocity V.sub.R from the vehicle reference velocity V.sub.ref, this value is again decreased in stages so that a normal controlled braking process is not affected.
Claims15
A motor vehicle fluid pressure responsive braking system antilocking mechanism, which prevents locking of an individual brake on such motor vehicle by providing a respective antilock control signal to a plurality of respective solenoid control valves, secured to such motor vehicle in a position to control fluid pressure response to a respective brake cylinder associated with each respective wheel on such motor vehicle, said braking system antilocking mechanism comprising:
- (a) a plurality of wheel velocity sensing means secured to such motor vehicle in a position for sensing rotational velocity of such each respective wheel;
- (b) a first signal generating means, connected to each of said plurality of sensing means, for generating a first signal having a value that is at least representative of a deceleration of such each respective wheel;
- (c) a signal evaluating and detection means connected to receive said first signal for (1) evaluating said first signal with respect to a first threshold value which is larger than a normally favorable value in a controlled braking application on such motor vehicle;
- and (2) detecting when a respective wheel velocity is beginning to separate from a wheel vehicle reference velocity;
- (d) a logic control circuit means, connected to receive a signal from said first signal evaluating and detection means for generating an antilock control signal, according to a preset program, when said first signal value exceeds said threshold value;
- (e) an antilock control signal transmitting means, connected to said logic control circuit means and to such respective solenoid control valves, for transmitting said antilock control signal to such respective solenoid control valves to thereby adjust fluid pressure response in such respective brake cylinder;
- and
- (f) decrement means, connected to said signal evaluating and detection means, for decreasing said first threshold value in stages when said respective wheel velocity separates from said vehicle reference velocity.
A method to prevent locking of an individual brake in a motor vehicle fluid pressure responsive braking system, said method comprising the steps of:
- (a) determining a rotational velocity of each respective wheel on such motor vehicle;
- (b) generating a first signal value that is representative of said rotational velocity determined in step (a);
- (c) determining at least when a deceleration of such each respective wheel occurs from said first signal generated in step (b);
- (d) evaluating said first signal with respect to a first threshold value which is larger than a normally favorable value in a controlled braking application of such motor vehicle when a deceleration of such each respective wheel is determined in step (c);
- (e) detecting when a respective wheel velocity starts to separate from a vehicle reference velocity;
- (f) generating an antilock control signal, according to a preset program in a logic control circuit device, when said first signal evaluated in step (d) exceeds said first threshold value;
- (g) transmitting said antilock control signal, generated in step (f), to respective solenoid control valves;
- (h) adjusting fluid pressure in respective brake cylinders in response to such solenoid control valves;
- and
- (i) decreasing said first threshold value in stages in step (d) when said respective wheel velocity starts to separate from said vehicle reference velocity detected in step (e).
Dependencies are inferred from the claim text.