BRAKE BOOSTER PROVIDING VEHICULAR HILL HOLDER

A brake booster (10, 210, 310) connected to a control circuit (120) provides for continued braking of a vehicle when the vehicle is situated on an incline and the brake pedal (92) is released by the operator. Continued brake application is accomplished by utilizing a control circuit (120) responsive to vehicular attitude, clutch pedal position, ignition status, vehicular speed, and vehicular direction. The control circuit (120) is connected to a combination check valve and three-way solenoid valve (100, 200, 300) connected to a movable wall brake booster (10, 210, 310). The combination valve (100) is connected to a flexible hose (110) disposed interiorily of the booster (10), the other end of the flexible hose (110) connected to the input opening (32) of a three-way poppet valve (70) located at the central hub (30) of the booster (10). When the control circuit (120) senses that the vehicle is on an incline, the clutch pedal depressed, the ignition "on", the speed is zero, and the vehicle not backing up, it actuates the three-way solenoid of valve (100) which continues to supply a first fluid pressure to the front booster chamber (40) while supplying a second fluid pressure for the rear booster chamber (50) via the flexible hose (110) and poppet valve 170. The vehicle operator may release the brake pedal (92) which returns slightly toward an inactive position and which opens slightly valve (70), with the brakes remaining activated because the second fluid pressure is provided to the rear chamber (50) via the hose connection (110) and valve (70) to maintain the axially displaced position of the movable wall (24).