An electropneumatic parking brake system for a utility vehicle includes a precontrol module configured to control at least a first control pressure. The precontrol module has a precontrol store connection configured to receive a store pressure from a compressed air device and at least one precontrol valve combination. The electropneumatic parking brake system further includes at least one manually actuatable sliding valve connected to a valve store connection and having a parking brake connection. The parking brake connection is ventilated in a first switching position of the sliding valve and a parking brake pressure at the parking brake connection is controllable in a second switching position of the sliding valve. The sliding valve has a first pneumatic control connection at which the first control pressure is configured to be controlled in order to pneumatically switch the sliding valve.

An electropneumatic valve arrangement is for actuating a parking brake function of an electropneumatic brake system of a commercial vehicle, with a pilot control unit, which modulates a pilot pressure in dependence on an electronic parking brake signal, and which is configured to be self-holding, wherein the pilot pressure can bring about a modulation of a parking brake pressure at least at one spring accumulator connection or can be modulated as such. The valve arrangement also has an emergency release connection with an emergency release path for optionally inputting an emergency release pressure, which brings about the modulation of the parking brake pressure at the at least one spring accumulator connection.

An electronically controllable pneumatic brake system in a vehicle includes wheel brakes for braking respective wheels of the vehicle. Wheel brakes of at least one vehicle axle include spring-loaded cylinders for implementing a pneumatic parking brake in a parking brake braking circuit of the vehicle. The brake system further includes an electronically controllable monostable bypass valve, wherein the monostable bypass valve is disposed between a manually operated parking brake valve and the spring-loaded cylinders. The monostable bypass valve controls, in a first switching position, a bypass control pressure based on an actuation pressure produced by the parking brake valve to implement a manually specified parking brake force. The monostable bypass valve further controls, in a second switching position, a bypass control pressure depending on a venting pressure prevailing in a bypass vent connection to implement an electrically specified parking brake force.

An electropneumatic parking brake device is for supplying air to and exhausting air from spring-loaded accumulator brake cylinders of an electronically controllable pneumatic braking system for a vehicle and includes a parking brake valve unit with a reservoir port for receiving reservoir pressure from a parking brake reservoir. The parking brake valve unit sets a parking brake pressure at a spring-loaded accumulator port depending on a parking brake signal. A non-return valve is arranged between the parking brake valve unit and the parking brake reservoir to prevent compressed air from flowing back from the parking brake valve unit to the reservoir. A bypass valve is provided which can be switched to supply air to and exhaust it from the spring-loaded accumulator port. The bypass valve is activated and switched independently of the parking brake valve unit.

An electropneumatic valve arrangement is configured to actuate a parking brake function of an electropneumatic brake system of a commercial vehicle, with a bistable pilot control unit having an electromagnetic solenoid valve, which modulates a pilot pressure in dependence on an electronic parking brake signal; and a main valve unit, which receives the pilot pressure and modulates a parking brake pressure at least at one spring accumulator connection in dependence on the pilot pressure. The solenoid valve has a safety control connection for receiving a safety control pressure, supplies the pilot control unit with supply pressure or connects it to an air-purging in dependence on the safety control pressure. The safety control pressure is a pressure modulated by the solenoid valve or a pressure derived from it. A method is for controlling a parking brake function of a commercial vehicle having an electropneumatic brake system.

Disclosed is an electro-hydraulic relay valve and corresponding valve assembly for a SAHR brake. First actuators are arranged to act on a first end of a floating valve spool and second actuators are arranged to act on a second end of the valve spool. One of the second actuators can receive hydraulic pressure from a pilot valve. In a first valve position, the pressure supply port communicates with the working port and the tank port is closed. In a second valve position, the pressure supply port is closed and communicates via a first sense line with one of the first actuators, the working port directs pressure to the tank port, the tank port communicates via a second sense line with another of the first actuators, and the working port communicates via a third sense line with one of the second actuators. In a central position, all three ports are closed.

A vehicle includes a chassis, a tractive element coupled to the chassis, and a parking brake system. The chassis includes at least one of a transmission or a structural frame. The parking brake system includes a parking brake configured to brake the tractive element when engaged. The parking brake is configured to be disengaged to permit rotation of the tractive element in response to the parking brake receiving a fluid. The parking brake system includes a fluid supply configured to supply the fluid to the parking brake to disengage the parking brake. The fluid supply is configured to stop supplying the fluid in response to a component of the vehicle ceasing operation. The parking brake system includes a pump coupled to the chassis and configured to supply the fluid to the parking brake at least when the component of the vehicle is not operating.

A vehicle locked wheel detector detects initial trailer movement or enablement thereof, for example using a spring brake air pressure switch. The outputs from ABS wheel rotation sensors are monitored to determine whether all wheels are rotating. If one wheel is not rotating, then a locked wheel indicator alerts the driver that one of the wheels may be locked. In some embodiments, if both wheels on one side of the trailer are either stationary or rotating below a threshold speed and the wheels on the opposite side are rotating relatively more quickly, then the trailer is presumed to be pivoting around a sharp turn, and so the wheels will be presumed to be rolling. A finite temporal-spatial interval subsequent to initial trailer movement is defined within which wheel lock can be detected, and upon expiration of the temporal-spatial interval the ABS operates in a normal manner.

A brake system for a trailer has first and second pneumatic circuits for supplying air pressure to the wheel ends on the trailer. The air pressure to brake devices at the wheel ends is controllable via a first brake ECU. First and second pressure control valves control pressure from the pneumatic circuits to the respective wheel ends. The system further has a second ECU adapted to electrically control the actuation of the pressure control valves.

An electropneumatic brake system for a vehicle has a parking brake system having a parking brake valve unit constructed to adjust a parking brake pressure on at least one spring loading connection in accordance with a pilot control pressure. The valve unit has a pilot control unit which in accordance with an electronic parking brake signal adjusts the pilot control pressure on a pilot control path. The parking brake unit has an additional brake pressure connection which is or can be pneumatically connected to the pilot control path to introduce an emergency release pressure. The introduction of the emergency release pressure on the additional brake pressure connection causes the adjustment of the parking brake pressure on at least one spring loading connection. A first control unit is configured to provide the electronic parking brake signal to the valve unit. The electropneumatic brake system can have an emergency release valve unit.