Patent attributes
An electronically controlled pneumatic brake system for a vehicle, with a normal brake operating mode (NOM) and a backup brake operating mode (BKM), said system comprising:a front axle brake module (FBM) for providing pneumatic control pressure to the left and right front pneumatic brake actuators (FW-L, FW-R), one or more rear axle brake module (RBM) for providing pneumatic control pressure to the left and right rear pneumatic brake actuators (RW-L, RW-R), a trailer brake interface (5),an air production module (6) selectively providing air under pressure to said axles electronic brake modules (FBM, RBM) via first and second air supply circuits (AC1,AC2), a trailer relay valve (1), wherein each of the front and rear axle brake modules (FBM, RBM) is controlled by an electrical control signal (NBC, ES1,ES2) under the normal brake operating mode (NOM) and is controlled by a pneumatic backup brake control line (BKC) under the backup brake operating mode (BKM), wherein the output (12) of trailer relay valve is connected to the trailer brake interface (5) under the normal brake operating mode (NOM), and the output (12) of trailer relay valve is connected to the pneumatic backup brake control line (BKC) under the backup brake operating mode (BKM).