HYDRAULIC CONTROL UNIT FOR A VEHICULAR ANTI-LOCK BRAKE SYSTEM HAVING A PAIR OF NORMALLY OPEN CONTROL VALVES FOR CONTROLLING PRESSURE TO A WHEEL BRAKE

摘要

A hydraulic control unit for use in a vehicular anti-lock braking system includes a housing. A plurality of first control valves is disposed in the housing for modulating the flow of hydraulic fluid to a plurality of corresponding wheel brakes during an anti-lock braking event. A plurality of second control valves is disposed in the housing for modulating the flow of hydraulic fluid from a plurality of corresponding wheel brakes during an anti-lock braking event. A pump is disposed in the housing in fluid communication with the first and second control valves for transferring hydraulic fluid from the second control valves to the first control valves during an anti-lock braking event. At least one of the first control valves and at least one of the second control valves are normally open solenoid valves for movement between a normally open position and a closed position.