Patent ID: 6213572
Filing Date: 2001-04-10
Classification: B60T

Abstract:
An electro-hydraulic brake system comprising:a wheel brake;a reservoir of hydraulic fluid;a pump for selectively pumping hydraulic fluid from said reservoir and supplying pressurized hydraulic fluid to said wheel brake for applying a braking force during normal brake apply;an apply valve in fluid communication with said wheel brake for selectively permitting flow of pressurized hydraulic fluid from said pump to said wheel brake;a dump valve in fluid communication with said wheel brake for selectively permitting flow of pressurized hydraulic fluid from said wheel brake to said reservoir;a brake pedal;a master cylinder operated by said brake pedal for pressurizing hydraulic fluid;an isolation valve in fluid communication with said wheel brake for selectively permitting flow of pressurized hydraulic fluid from said master cylinder to said wheel brake;a sensor sensing the position of said brake pedal and generating a pedal position signal representative of the position of said brake pedal; andan electronic control unit for receiving said pedal position signal, said pedal position signal being utilized to determine a brake demand, said electronic control unit controlling the operation of said pump, and said apply, dump, and isolation valves to achieve a desired braking force at said wheel brake based on said brake demand and to regulate pressure generated by said master cylinder to achieve a predetermined relationship between pressure generated by said master cylinder and position of said brake pedal, whereby a desired pedal feel is achieved substantially continuously during brake apply.