Kelsey-hayes Company

Louis S Tang

Richard J Barron

Harry A Hunnicutt

Mark D Lubbers

Gregory J Krawczyk

A vehicle hydraulic system is disclosed comprising a hydraulic fluid reservoir; a pressure force supplying pressurized hydraulic fluid to a discharge header; a fluid conduit between the discharge header and the reservoir; a back pressure valve operative in the fluid conduit to maintain a desired pressure in the discharge header; and a vehicle braking system having a hydraulically operated boost piston assembly for supplementing a force exerted by a vehicle operator to operate brakes of the vehicle braking system. The system further includes a boost pressure control valve responsive to an input from the vehicle operator for selectively directing pressured hydraulic fluid from the discharge header to the boost piston assembly and venting hydraulic fluid from the boost piston assembly to the reservoir.

Electronically controlled hydraulic brake boost pressure control system

A reservoir including a housing having a chamber formed therein for the storage of hydraulic brake fluid. The chamber is in fluid communication with a master cylinder. The housing has an opening which is in communication with the atmosphere. The housing further including a passageway in communication with the cavity and the opening. A membrane is disposed in the passageway of the housing. The membrane has oleophobic properties such that the membrane permits the passage of air therethrough and substantially prevents the passage of brake fluid therethrough.

Growing community of inventors

Novi, MI, United States of America

Louis S Tang