Kelsey-hayes Company

Bernard W Johnson

Mark S Luckevich

Dan Negrin

Brian C Tuck

A control method and system for a vehicle anti-lock brake system to provide for recovery from premature activation of the vehicle anti-lock brake system. The control system includes a microprocessor and accompanying components to perform the control method steps of generating an input signal representing a vehicle wheel velocity, processing the input signal to determine a wheel slip duration, comparing the wheel slip duration to a slip duration threshold, generating a premature activation recovery control signal when the wheel slip duration fails to exceed the slip duration threshold, and performing premature activation recovery control of the anti-lock brake system in response to the premature activation recovery control signal.

Early activation recovery control method and system for vehicle

A brake pressure controller, responsive to a wheel speed sensor and coupled to a brake, performs a cyclic control of pressure applied to the brake. A brake pressure cycle includes a pressure apply stage and a pressure dump stage having activation conditions based upon a slip threshold parameter. A predetermined base threshold quantity is modified in dependence upon a measured time duration of the pressure dump stage and/or a slip depth error quantity so that a greater amount of slip is added to the base slip threshold when braking on a deformable surface than when braking on a non-deformable surface.

Method and system for antilock braking on a deformable surface

A method and system for controlling an anti-lock brake system cycle rate in a vehicle wherein the cycle includes a primary apply stage and a secondary apply stage in which increasing pressure is applied to the brake. The primary and secondary stages are separated by a hold stage in which a substantially constant pressure is applied to the brake for a time interval which varies as a function of the estimated average vehicle deceleration.

Anti-lock brake method and system including a variable primary to

A method and system for damping wheel speed oscillation during an anti-lock braking event. The method includes the initial step of sensing the wheel speed and determining a wheel slip based on the sensed wheel speed and a vehicle speed reference. Next, the method continues with the step of determining whether the wheel slip has exceeded a predetermined slip threshold. If the wheel slip has not exceeded a predetermined slip threshold, the method performs normal or unmodified anti-lock brake control. If the wheel slip has exceeded the predetermined slip threshold, the method continues with the step of determining whether an acceleration feedback condition representative of a high mu surface has been satisfied. If an acceleration feedback condition has been satisfied, the method continues with the step of increasing brake pressure applied to the wheel from a steady-state level in a step-wise function during acceleration of the wheel before the wheel speed reaches the vehicle speed reference. The brake pressure is applied as a function of the wheel acceleration. If an acceleration feedback condition has not been satisfied, the method applies normal anti-lock brake control.

Method and system for damping wheel speed oscillation on vehicles having

Methods for brake pressure control in a vehicular antilock brake system wherein brake pressure is restored to within a window of peak brake pressure after a reduction in pressure in response to a forced departure during vehicle braking. In a preferred embodiment, the pressure reduction is adaptively controlled. The vehicle has a plurality of wheels and each wheel has brake. The method includes increasing brake pressure at a wheel so as to attain a prereduction peak brake pressure, and initiating a pressure reduction mode of operation wherein brake fluid flows from the brake of the wheel. The method also includes restoring the brake pressure at the wheel to the desired brake pressure after termination of the pressure reduction mode of operation without making actual brake pressure measurements.

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Brighton, MI, United States of America

Bernard W Johnson