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US 5,261,730 AGranted
Brake pressure control device
AssigneeMercedes-Benz AG
InventorsManfred Steiner, Werner Reichelt
Life of this patent
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AssigneeMercedes-Benz AG
InventorsManfred Steiner, Werner Reichelt
Estimating the term…
A hydraulic twin-circuit brake system for a road vehicle with front axle/rear axle brake circuit division, is equipped both with an anti-lock brake system (ABS) and an acceleration skid regulation device (ASR) which operates on the principle of slowing down a driven vehicle wheel tending to spin by activating its wheel brake. A brake pressure control device analogous to the acceleration skid regulation device is also provided for the brake circuit of the non-driven front wheels of the vehicle. This brake pressure control device, together with the acceleration skid regulation device for the driven rear wheels of the vehicle, is activated in the sense of an automatic brake pressure control when the driver actuates the brake pedal at a rate which is larger than a specified threshold value .phi..sub.s. The brake pressure is then automatically controlled such that optimum vehicle deceleration occurs. Buffer reservoirs which are connected to the outlet pressure spaces of the brake unit, instead of to the wheel brakes, during automatic braking achieve a pedal displacement simulation by way of which an electronic control unit recognizes the vehicle deceleration which the driver wishes to select by the brake pedal actuation.
A brake pressure control device for a road vehicle having a pedal-actuated brake unit, a hydraulic multi-circuit brake system with static brake circuits, into which brake system pressures proportional to a pedal force can be connected by actuation of the brake unit, and an anti-lock brake system configured for dynamically stable deceleration behavior of the road vehicle and having a sensor device operationally arranged for recording the position of one of a brake pedal and of a brake unit element connected to the motion of the brake pedal and generating electrical output signals characteristic of the instantaneous position of the brake pedal, an electronic control unit for processing the output signals and generating control signals for an electrically controllable brake pressure setting device so that at least a higher brake pressure than an expected brake pressure value associated with the instantaneous pedal position is connected with front wheel brakes at least whenever the speed with which a position of a pedal changes during a brake pressure build-up actuation is greater than a specified threshold value in excess of zero, and at least one buffer reservoir controllable, via an operatively associated respective valve, by output signals of the electronic control unit and configured to be pressurized against a lower return force than that corresponding to a reaction force resulting from a reaction of the brake pressure on the brake unit, wherein the at least one buffer reservoir is operatively arranged to be connected, by position selection of the valve by an output signal of the electronic control unit actuating the brake pressure control device to a pressure outlet of the brake unit which is associated with that brake circuit in which higher level brake pressure occurs, and an outlet pressure space of the brake unit connected to the at least one buffer reservoir is shut off, under valve control, from the brake circuit subjected to the increased brake pressure on actuation of the brake pressure control device.
Dependencies are inferred from the claim text.