Trailer control valve for a compressed air brake system for motor vehicles

A trailer control module (13) for introducing a control pressure into brake lines of a trailer comprising an electrically and a pneumatically controllable trailer control valve (14), said control valve is controlled by means of an electrical control circuit (25) and a pneumatic control circuit (26) of a service brake system (11) as well as of a pneumatic control circuit (37) of an auxiliary brake system (12), the pneumatic control circuit (26) is fed from a first compressed air reservoir (19) that is a part of the service brake system (11), and is able to control the trailer control valve (14) in place of the electrical control circuit (25), said trailer control module has control pistons for actuating a double seat valve (91) which controls a communication between a second compressed air reservoir (36), a compressed air consumer, and a pressure relief location (3),

• a control piston (90), which is jointly associated with the electrical control circuit (25) and the pneumatic control circuit (26) of the service brake system (11), is provided in the trailer control valve (14),
• a valve (46) is provided, which is connected to the pneumatic control circuit (26) of the service brake system (11) and closes off the pneumatic control circuit (26) of the service brake system (11) to the trailer control valve (14) when the electrical control circuit (25) is functional, and in the event of a failure of the electrical control circuit (25), said valve (46) unblocks the pneumatic control circuit (26) of the service brake system,
• as a part of the control module (13), the electrical control circuit (25) of the service brake system (11) is connected to an inlet valve (48) and an outlet valve (47), said inlet valve (48) and said outlet valve (47) are embodied as electromagnetically actuated 2/2-way valves that are closed when without current, the inlet valve (48) is connected to the second compressed air reservoir (36) of the auxiliary brake system (12) on an inflow side, and on an outflow side is connected to a control chamber (89) associated with the common control piston (90) of the trailer control valve (14), while the outlet valve (47) is connected to the control chamber (89) on an inflow side, and is connected to the pressure relief location (3) on an outflow side.