Power assisted braking system

摘要

A method of controlling a retarder brake system of a vehicle. The method comprises the steps of determining an operator braking input indicative of a desired vehicle deceleration and generating a desired retarder torque value (DT) corresponding to the desired vehicle deceleration value. The method further includes determining a wheel speed value for each wheel of the vehicle and generating a front-to-rear wheel slip (FRS) value indicative of rear wheel lockup as a function of the wheel speed values. A retarder torque reduction (TR) value is also generated as a function of the FRS value. A desired retarder torque command (TC) is then generated as a function of the DT and TR values. The method also includes the step of controlling the retarder as a function of the retarder torque command to achieve the desired vehicle deceleration. Thus, the TR value reduced the retarding torque which would otherwise be applied in response to the driver input, to prevent driven wheel lockup.