Brake system for motor vehicles having a brake power assist unit

Abstract

A brake system for motor vehicles according to the invention has a brake power assist unit which generates an output brake power by superimposing an auxiliary power on a control power input by the brake pedal, and a hydraulic wheel brake regulating system which can generate a higher pressure in the wheel brake cylinder than the pressure set by the output brake power. An analysis device recognizes when the ratio of the auxiliary power to the control power falls below a predetermined value, after which a control device causes the hydraulic wheel brake regulating system to generate a desired pressure in the wheel brake cylinders which at least partially compensates the effect on the actual pressure due to the auxiliary power decreasing in relationship to the control power. The point at which the ratio of the auxiliary power to the control power falls below the predetermined value may be detected by a mechanical stop which interacts with an electric sensor device and/or by an electric signal which is emitted by a pressure sensor device when the auxiliary pressure is at least almost completely exhausted.

Dependencies are inferred from the claim text.