초록 ▼

Disclosed is a method and apparatus for controlling application and release of brake pressure in automotive vehicle brakes in order to prevent the vehicle from skidding. The system has a component for determining the coefficient of friction between the road surface and a tire tread, operative to det

Disclosed is a method and apparatus for controlling application and release of brake pressure in automotive vehicle brakes in order to prevent the vehicle from skidding. The system has a component for determining the coefficient of friction between the road surface and a tire tread, operative to determine that coefficient as a function of the wheel acceleration, wheel load and brake torque. Additionally there is provided a circuit for detecting a peak of the friction coefficient during a control cycle, as well as circuitry for determining wheel r.p.m. and for determining target wheel r.p.m. The latter function is performed on the detected wheel r.p.m. responsively to detection of the peak of the friction coefficient. Additionally, a control device is provided for controlling applying and releasing of fluid pressure to wheel cylinders for skid controlling the rate of wheel deceleration. The target wheel r.p.m. determining circuit determines a deceleration coefficient of wheel r.p.m. based on the difference of wheel r.p.m. between the time of detecting the peak of the friction coefficient and the time of detecting the immediately preceding peak, and the length of the interval between detecting the peaks. The circuit determines the target wheel r.p.m. by subtracting a time varying amount, obtained as a function of the determined deceleration coefficient, from the wheel r.p.m. determined at the time of detecting of the peak of the friction coefficient.

대표청구항 ▼

A brake control system for an automotive vehicle for controlling application and release of brake pressure to a wheel cylinder to prevent a vehicle from skidding, including: a first means for detecting wheel r.p.m. and for sequentially generating in a plurality of operating cycles a first signal ind

A brake control system for an automotive vehicle for controlling application and release of brake pressure to a wheel cylinder to prevent a vehicle from skidding, including: a first means for detecting wheel r.p.m. and for sequentially generating in a plurality of operating cycles a first signal indicative of the detected wheel r.p.m. a second means for determining a coefficient of friction between a tire tread and a road surface and for generating a second signal indicative of the determined coefficient of friction, a third means for determining a target wheel r.p.m. and for generating a third signal indicative of the determined target wheel r.p.m., a fourth means for controlling application and release of brake pressure to the wheel cylinder operable to release the brake pressure when the value of said first signal drops to be equal to or less than the value of said third signal and a fifth means for detecting presence of a peak of said second signal in each cycle of skid control operation and for generating a fourth signal; said third means being responsive to said fourth signal to hold a signal value of said first signal in each cycle of skid control operation for determining a deceleration coefficient of the wheel r.p.m. based on the held values of said first signal generated in the current cycle and in an immediately preceding cycle of skid control operation and further based on an interval between occurrences of said fourth signal, for determining a ramp signal during the next cycle of skid control indicative of deceleration of the target wheel r.p.m. in the next cycle of skid control operation and based on the determined deceleration coefficient, and for determining the target wheel r.p.m. by subtracting the value of said ramp signal from a value of said first signal obtained in response to said fourth signal. In an anti-skid brake control system for an automotive vehicle for controlling application and release of brake pressure to a wheel cylinder to prevent a vehicle from skidding, which system includes a first means for detecting wheel r.p.m. and for sequentially generating a first signal indicative of the detected wheel r.p.m., a second means for determining a friction coefficient between a tire tread and a road surface and for generating a second signal indicative of the determined friction coefficient, a third means for determining a target wheel r.p.m. and for generating a third signal indicative of the determined target wheel r.p.m. and a fourth means for controlling application and release of brake pressure to the wheel cylinder operable to release the brake pressure when the value of said first signal drops to be equal to or less than the value of said third signal, a method for determining the target wheel r.p.m. comprising in combination the steps of: determining a friction coefficient between a tire tread and a road surface; discriminating a peak of said friction coefficient in each cycle of skid control operation and generating a peak signal responsive to detection of said peak; holding a value of said first signal at the time of detection of said peak of said friction coefficient; measuring an interval between occurrences of said peak signal; determining a variation of first signal values in each said interval; dividing said variation by the length of said interval to obtain a deceleration coefficient; determining a value of a ramp signal based on the obtained deceleration coefficient; and subtracting said value of said ramp signal from the value of said first signal at the time of detecting said peak of said friction coefficient.