Method for brake control of a vehicle combination

A method for controlling the brakes of a vehicle combination, the method comprising:

• providing a vehicle combination comprising:
• a tractor vehicle having a hydraulic or pneumatic brake system;
• at least one trailer vehicle configured to be coupled to the tractor vehicle and having a pressure-controlled pneumatic brake system;
• an electronic control unit (8);
• and
• an electronically controlled brake control valve (2) arranged in the tractor vehicle and comprising at least two magnetic switching valves that include an inlet valve (12) and an outlet valve (14), the at least two magnetic switching valves configured to be controlled by the electronic control unit (8);
• and
• a brake control line (42, 42′) that runs from a brake control outlet (p22) of the brake control valve (2) to a “Brake” coupling head (6) of the tractor vehicle or to a trailer brake valve of the trailer vehicle and/or a “Brake” coupling head at the rear of the trailer vehicle;
• producing, by means of the brake control valve (2), a brake control pressure (pBC) in the brake control line (42, 42′);
• determining a current trailer status of the tractor vehicle and/or a current line volume (VBC) of the brake control line (42, 42′), thereby determining whether the tractor vehicle is connected to the at least one trailer vehicle and/or determining a line volume (VBC) of the brake control line (42, 42′);
• specifying a target pressure (pZ) to be produced in the brake control line (42, 42′);
• producing the target pressure (pZ) in the brake control line (42, 42′) by pulse-like opening of the inlet valve (12) and/or by pulse-like opening of the outlet valve (14);
• measuring the brake control pressure (pBC) in the brake control line (42, 42′) by sensor means during pressure build-up;
• determining, from a time variation of the brake control pressure (pBC) and/or a time variation of switching states of the inlet valve (12) and/or the outlet valve (14) until the target pressure (pZ) has been reached, a characteristic value for the trailer status of the tractor vehicle and/or the line volume (VBC) of the brake control line (42, 42′);
• comparing the characteristic value with at least one reference value determined as a function of the trailer status of the tractor vehicle and/or as a function of the line volume (VBC) of the brake control line (42, 42′), wherein the at least one reference value is stored in a data memory of the control unit (8);
• and
• determining the line volume (VBC) of the brake control line (42, 42′) based on a result of comparing the characteristic value with the at least one reference value.

A method for controlling the brakes of a vehicle combination, the method comprising:

• providing a vehicle combination comprising:
• a tractor vehicle having a hydraulic or pneumatic brake system;
• at least one trailer vehicle configured to be coupled to the tractor vehicle and having a pressure-controlled pneumatic brake system;
• an electronically controlled brake control valve (2) arranged in the tractor vehicle, the electronically controlled brake valve comprising at least two magnetic switching valves that include an inlet valve (12) and an outlet valve (14), wherein the brake control valve (2) is configured to produce a brake control pressure (pBC) in a brake control line (42, 42′) that runs from a brake control outlet (p22) of the brake control valve (2) as far as a “Brake” coupling head (6) of the tractor vehicle or as far as a trailer brake valve of the trailer vehicle and/or a “Brake” coupling head at the rear of the trailer vehicle;
• determining a current trailer status of whether the tractor vehicle is connected to the at least one trailer vehicle and/or determining a line volume (VBC) of the brake control line (42, 42′);
• specifying a pneumatic pressure pulse to be produced in the brake control line (42, 42′) with a fixed opening duration (ΔtIV) of the inlet valve (12);
• producing the pressure pulse in the brake control line (42, 42′) by a pulse-like opening of the inlet valve (12);
• determining, by sensor means and after a specified time interval (ΔtP) after closing the inlet valve (12), a brake control pressure (pBC) in the brake control line (42, 42′) as a residual pressure (ΔpR);
• comparing the residual pressure (ΔpR) with a reference pressure value determined beforehand as a function of the trailer status of the tractor vehicle and/or of the line volume of the brake control line and stored in a data memory of the control unit (8);
• and
• determining, based on a result of comparing the residual pressure, the current trailer status of the tractor vehicle and/or the line volume (VBC) of the brake control line (42, 42′).