Volkswagenwerk Aktiengesellschaft

Peter Hattwig

A hydraulic dual-circuit brake system for automobiles, comprising wheel brakes positioned at the front and rear wheels, a master brake cylinder, brake lines for transmitting brake pressure from the master brake cylinder to the wheel brakes to actuate the latter, a brake pressure regulator device incorporating a hydraulically operated switching off device interposed between the rear wheel brakes and the master brake cylinder, and a brake slip regulation device including a hydraulic unit, sensors for providing a signal output representative of wheel movement behavior, and an electronic anti-skid control and regulating device responsive to the signal output for controlling the hydraulic unit to affect the brake pressure transmitted by the hydraulic unit to the switching off endangered wheel brake. The hydraulically operated locking device of the brake pressure regulator device responds to the brake pressure transmitted by the hydraulic unit to the locking-endangered wheel brakes and modifies the operation of the brake pressure regulator device to affect the brake pressure delivered to the rear wheel brakes by the brake pressure regulator device.

Hydraulic dual-circuit brake system for automobiles

A pump-less hydraulic brake system has a pair of independent brake lines, each connected to diagonally opposed front and rear wheel brakes, and a control valve mechanism disposed in each brake line. Each control valve mechanism has an electrically connectable inlet valve and outlet valve, actuatable to one of three combinations: (1) in which brake line pressure is determined by the brake pedal-actuated master cylinder; (2) in which the braking pressure in the respective brake line drops, and (3) in which the braking pressure remains steady. A pair of rear brake inlet valves are also provided, and the valves are controlled as a function of the relative rpm or changes in deceleration of the vehicle wheels. The rear brake inlet valves are also independently controlled, to limit maximum braking pressure to the rear wheel brake, as a function of rear axle weight. No more than one vehicle wheel locks at a give time, and vehicle stability and maneuverability, in combination with relatively high braking pressures, are assured.

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Cremlingen, Germany

Peter Hattwig