Patent ID: 6467854
Filing Date: 2002-10-22
Classification: B60T,F15B,F16K,Y10T

Abstract:
A pre-engagement unit for a braking pressure modulator for a pressure regulating circuit of an electronic braking system, said pre-engagement unit being implemented in a trailer vehicle to be coupled to a tractor vehicle, comprising:a) a first pneumatic inlet through which a supply pressure is supplied to the pre-engagement unit; b) a second pneumatic inlet through which a redundancy pressure is supplied to the pre-engagement unit by a trailer braking valve located in said trailer vehicle, said redundancy pressure being derived from a braking pressure transmitted from said tractor vehicle to said trailer vehicle via pneumatic lines; c) a first pneumatic output terminal through which the pre-engagement unit is connected to an air quantity augmenting relay valve; d) a second pneumatic output terminal through which the pre-engagement unit is connected to a pressure sink; e) an electrically actuated valve system comprising first, second, and third 2/2-way solenoid valves each of which has an electric terminal which is connected to an output terminal of an electronic control unit of the electronic braking system, each of said 2/2-way solenoid valves also including first and second pneumatic terminals which are selectively connected to said first and second pneumatic inlets and said first and second pneumatic output terminals of said pre-engagement unit so that the pressure in the pressure regulating circuit can be increased, decreased, or maintained.