A method for testing a pressure-medium-operated electronic brake system of a vehicle having a valve and sensor device including a control pressure inlet, a control pressure outlet, a plurality of valves selected from electrically activated inlet valves, outlet valves, redundancy valves, and pressure valves, an actual pressure sensor for measuring an actual control pressure, a setpoint pressure sensor for measuring a setpoint control pressure, and an electronic control unit, which has a signal-conducting connection to the electrically activated valves and pressure sensors, for receiving pressure signals and actuating the electrically activated valves, includes testing the setpoint pressure sensor while the control unit is in a passive operating mode, passing the setpoint control pressure directly through to the control pressure outlet, measuring the actual pressure at the control pressure outlet using a sensor, and transmitting the measured value to the control unit for plausibility checking against the setpoint pressure measurement.

A valve-arrangement is operable to switch between a bistable-valve (BV) behavior and a relay-valve (RV) behavior to control a parking-brake, and includes a housing with a supply-pressure-inlet (SPI), a service brake-control-inlet (SBCI) to provide a control-pressure, a pressure-outlet, and an exhaust-port, and includes a first-piston and a second-piston both movable along a same direction in the housing to define a first-chamber communicating with the SBCI, a second-chamber between the first-piston and the second-piston, and third chamber communicating with the pressure-outlet and with a controllable connection to the SPI, in which upon the control-pressure the second-piston moves with the first-piston to connect the pressure-outlet with the exhaust-port or with the SPI. The valve arrangement includes a throttle unit adapted, depending on the control-pressure, to connect the second-chamber with the third-chamber to enable the BV behavior or disconnect the second-chamber from the third-chamber to enable the RV behavior.

A method for driving a parking brake of a vehicle (V) wherein: for a setpoint between 0 and C1, the control pressure (200) is zero, and the supplementary pressure (100) is nonzero constant; for a setpoint between C1 and C3, the control pressure is proportional to the setpoint, for a setpoint between C2 and Cmax, the supplementary pressure is zero;
said values being such that

0<C1<C2<Cmax, and

0<C1<C3<Cmax.

A method of brake control of a vehicle combination (2) composed of a tractor vehicle (4) with an electronically controlled braking system (5) and a trailer vehicle (6, 8) with a pneumatically controlled pneumatic braking system (7, 9), involves introducing the brake control pressure (p.sub.BC) of the trailer vehicle (6, 8) into a tractor brake control line (19) extending to a tractor vehicle-side “brake” coupling head (26) via an electronically controlled trailer control valve (13) of the tractor vehicle (4). At the beginning of a braking operation, a pressure pulse (34) exceeding a target brake control pressure (p.sub.BC_soll) is introduced into the tractor brake control line (19). The volume of a trailer brake control line (28, 29, 32) coupled to the “brake” coupling head (26) is ascertained, and the absolute value (Δp.sub.PI) and/or the duration (Δt.sub.PI) of the pressure pulse (34) introduced are/is established depending on the ascertained volume.

A method for testing a pressure-medium-operated electronic brake system of a vehicle having a valve and sensor device including a control pressure inlet, a control pressure outlet, a plurality of valves selected from electrically activated inlet valves, outlet valves, redundancy valves, and pressure valves, an actual pressure sensor for measuring an actual control pressure, a setpoint pressure sensor for measuring a setpoint control pressure, and an electronic control unit, which has a signal-conducting connection to the electrically activated valves and pressure sensors, for receiving pressure signals and actuating the electrically activated valves, includes testing the setpoint pressure sensor while the control unit is in a passive operating mode, passing the setpoint control pressure directly through to the control pressure outlet, measuring the actual pressure at the control pressure outlet using a sensor, and transmitting the measured value to the control unit for plausibility checking against the setpoint pressure measurement.

A vehicle brake system includes a hydraulic service brake system having a service brake circuit and a trailer brake control system. The trailer brake control system includes a trailer brake valve with a service brake demand input port and a trailer brake demand output port connected to a trailer brake control coupling. The output at the trailer brake demand output port is dependent on the pressure applied at the service brake demand input port. An electronic trailer brake control system has a solenoid control valve to connect the service brake demand input port to a source of pressurized hydraulic fluid to trigger an output at the trailer brake demand output port. An ECU is configured to actuate the control valve to apply the trailer brakes if it determines that the vehicle is at risk of jack-knifing. The system may also include a shuttle valve.

A method is provided for controlling a braking device which controls a braking force of towed vehicles in a combination vehicle which includes a towing vehicle and a plurality of towed vehicles towed by the towing vehicle, and in which the towing vehicle and the towed vehicle are coupled by a coupler and the towed vehicles are coupled by couplers. In the method for controlling the braking device, after the towed vehicle that is located on a rearmost side is made not to move, imparting a braking force to the plurality of towed vehicles towed by the towing vehicle starting in order from the towed vehicle located on a rear side.

A method is provided for controlling a braking device which controls a braking force of towed vehicles in a combination vehicle which includes a towing vehicle and a plurality of towed vehicles towed by the towing vehicle, and in which the towing vehicle and the towed vehicle are coupled by a coupler and the towed vehicles are coupled by couplers. In the method for controlling the braking device, after the towed vehicle that is located on a rearmost side is made not to move, imparting a braking force to the plurality of towed vehicles towed by the towing vehicle starting in order from the towed vehicle located on a rear side.

A brake retarder valve for a tractor-trailer combination includes a valve housing and a valve assembly. The valve assembly includes a poppet valve biased by a spring and a gravity spool. The valve assembly is selectively operable between the operative closed configuration and an open configuration in response to a resultant of the fluid pressure between a trailer axle brake and a tractor axle brake. The tractor axle brake is actuated with a time delay from actuation of the trailer axle brake. This delay is actuation of the tractor axle brake prevents jack knifing of the trailer onto the tractor in a tractor-trailer combination, thereby ensuring safety during operation of a tractor-trailer combination.

A brake retarder valve for a tractor-trailer combination includes a valve housing and a valve assembly. The valve assembly includes a poppet valve biased by a spring and a gravity spool. The valve assembly is selectively operable between the operative closed configuration and an open configuration in response to a resultant of the fluid pressure between a trailer axle brake and a tractor axle brake. The tractor axle brake is actuated with a time delay from actuation of the trailer axle brake. This delay is actuation of the tractor axle brake prevents jack knifing of the trailer onto the tractor in a tractor-trailer combination, thereby ensuring safety during operation of a tractor-trailer combination.