Trailer control valve of a towing vehicle

A trailer control valve of a towing vehicle for controlling a hydraulic dual-line brake system of a trailer vehicle, the trailer control valve comprising:

• a supply pressure inlet for the connection of a hydraulic supply line of the towing vehicle;
• a tank outlet for the connection of an unpressurized return-flow line of the towing vehicle;
• a brake pressure outlet for the connection of a brake line of the trailer vehicle;
• and
• a supplementary pressure outlet for the connection of a supplementary line of the trailer vehicle;
• wherein the brake pressure outlet is configured to be connected in a stepped manner by means of an electronically controlled brake control valve to the supply pressure inlet or to the tank outlet;
• wherein the supplementary pressure outlet is configured to be connected by way of a valve arrangement with at least one electronically controlled valve either to the supply pressure inlet, resulting in the reduction of an initial value of the supply pressure to a supplementary pressure, or connected to the tank outlet;
• wherein the valve arrangement comprises a pressure-limiting valve and a shut-off valve;
• wherein the pressure-limiting valve and the shut-off valve are arranged in series one after the other with the shut-off valve arranged fluidically downstream from the pressure-limiting valve;
• wherein the initial pressure of the valve arrangement can be reduced to the supplemental pressure by means of the pressure-limiting valve;
• and
• wherein the shut-off valve is in the form of a 3/2-way solenoid switching valve by means of which, when it is not energized, the supplemental pressure outlet is connected to the tank outlet but, when it is energized, the supplemental pressure outlet is connected to the working outlet of the pressure-limiting valve.