Patent ID: 8038226

Claim:
An electropneumatic brake system of a rail vehicle, containing a direct action electropneumatic braking device and an indirect action compressed-air braking device, and further comprising: a) a pressure regulator which produces a pilot control pressure (C v direct ) of the direct brake as a function of an electric brake pressure request signal of the direct brake, b) a pressure limiting valve which limits the pilot control pressure (C v direct ) of the direct brake to a predefinable, maximum pilot control pressure (C v direct max ) of the direct brake, c) a control valve which generates a pilot control pressure (C v indirect ) of the indirect brake as a function of a main air line pressure (p HL ) of the indirect brake, and d) a selection device which transmits, from the maximum pilot control pressure of the direct brake (C v direct max ) and the pilot control pressure (C V indirect ) of the indirect brake, a force corresponding to the respective larger pilot control pressure (C v direct max or C v indirect ) to a transmission, which changes the transmission ratio as a function of the respective load state of the rail vehicle by an actuating device and, which activates a relay valve, which controls a brake pressure (C) in accordance with the activation by the transmission, wherein the selection device is formed by a piston arrangement and/or diaphragm arrangement, having a first active surface which is connected axially fixed to a first piston rod, and a second active surface which transmits force only in one direction to the first piston rod, a first pressure chamber which is subjected to the pilot control pressure (C v indirect ) of the indirect brake being formed between the first active surface and the second active surface, and a second pressure chamber which is subjected to the maximum pilot control pressure C v direct max ) of the direct brake being formed between the second active surface and a wall of a housing.