A hydraulic circuit for an adaptive park braking system and method of operation thereof. The method of operating an adaptive park braking system includes providing a vehicle having a motor, a front axle system, a rear axle system, wherein the front axle system has one or more front axle braking systems and the rear axle system has one or more rear axle braking systems. Identifying when the vehicle is engaged in a digging operation. Disconnecting the front axle system or the rear axle system from driving engagement with the motor of the vehicle. Activating the one or more braking systems of the disconnect axle system to apply an amount of force to the disconnected axle system of the vehicle. Then applying an amount of torque with the motor to the axle system in driving engagement with the motor.

An automatic braking system and method are provided for controlling the automatic operation of a pneumatic (air) brake system installed on commercial highway vehicles and the like, particular heavy trucks and buses. When a possible collision is detected or an object is detected in proximity to at least one side and/or end of the vehicle, the system automatically operates the existing, factory installed air braking system of the vehicle to avoid a collision or mitigate the collision impact by concurrently pressurizing each of the rear and front pneumatic service brakes of the vehicle. Pressing the existing vehicle brake pedal deactivates the automatic braking system, thereby permitting the driver to take over control of braking at any time.

A valve control device includes a correction unit that corrects hysteresis in output of a control valve according to an increasing/reducing direction of a control output value; a detection unit configured to detect an actual output value to the control valve corresponding to the control output value; and a forbidding unit configured to forbid correction by the correction unit, until a difference between the control output value and the actual output value becomes within a predetermined range, after the increasing/reducing direction of the control output value is switched.

A power-assisted hydraulic braking system includes a main brake line into which a setpoint brake pressure can be introduced via a brake valve actuated by a brake pedal, and from which a plurality of wheel brake lines branch off, each leading to an actuating unit of a wheel brake, and a valve arrangement of an ABS controller, comprising an inlet valve disposed between the main brake line and one of the wheel brake lines and an outlet valve disposed between the relevant wheel brake line and a pressureless return line. The inlet valve and the outlet valve are embodied as pressure-controlled 2/2-way switching valves with suitably sized switching cross-sections. At least one pilot control valve is associated with each of the inlet valve and the outlet valve, via which a control connection can be alternately subjected to a low or high control pressure to change over.

As system for vehicle braking includes: a pedal actuated valve, including a first vent outlet in fluid communication with a fluid sink, a first supply inlet in fluid communication with a fluid source, and a first delivery outlet in fluid communication with a load; an electronically controlled valve in parallel with the pedal actuated valve, including a second vent outlet connected to the fluid sink via the first vent outlet, a second supply inlet in fluid communication with the fluid source, and a second delivery outlet in fluid communication with the load; and, a check valve connected between the load and the first delivery outlet downstream of the second vent outlet. A method for vehicle braking includes: operating at least one of the pedal actuated valve and the electronically controlled valve.

As system for vehicle braking includes: a pedal actuated valve, including a first vent outlet in fluid communication with a fluid sink, a first supply inlet in fluid communication with a fluid source, and a first delivery outlet in fluid communication with a load; an electronically controlled valve in parallel with the pedal actuated valve, including a second vent outlet connected to the fluid sink via the first vent outlet, a second supply inlet in fluid communication with the fluid source, and a second delivery outlet in fluid communication with the load; and, a check valve connected between the load and the first delivery outlet downstream of the second vent outlet. A method for vehicle braking includes: operating at least one of the pedal actuated valve and the electronically controlled valve.

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.

An electropneumatic valve assembly is for activating a parking brake function of an electropneumatic brake system. The valve assembly has a pilot control unit and a main valve unit configured to actuate a parking brake pressure at least at one spring-accumulator connection. The valve assembly has a service brake connection for receiving a service brake pressure and a safety valve. The safety valve, by receiving a safety control pressure, is switchable from a venting position, in which the safety valve connects the pilot control unit to a vent, to a supply position, in which the safety valve supplies the pilot control valve with reservoir pressure, the safety valve remaining in the supply position or switching to the venting position as a function of an actuated pressure. The service brake connection is connected to the safety valve control connection.

A membrane valve arrangement (1) includes a disc-shaped valve membrane (10) made from an elastic material and a disc (14) having a central opening (15). The valve membrane (10) is arranged with one side on the disc (14) and has a circumferential sealing bead (11) radially outside on the side opposite from the disc. The disc (14) is arranged, along with the valve membrane (10), between a housing upper part (2) and a housing lower part (6) of the membrane valve arrangement (1). The sealing bead (11) is clamped between the housing upper part (2) and the housing lower part (6). The sealing action in the region of the sealing bead is largely independent of tolerances because, on at least one of the housing parts in the region of the sealing bead (11) and/or in the radially outer peripheral region of the disc (14), additional sealing arrangements are present.

A valve unit for modulating pressure in a compressed-air brake system comprises an inlet valve (6) and an outlet valve (7) configured as diaphragm valves, a brake pressure output (4) configured to be connected to or shut off from a brake pressure input (3) or a vent output (5), two pilot valves (8, 9) configured as 3/2-way solenoid valves, and a respective control chamber (31, 32) adjacent to the diaphragm (17, 18) of the diaphragm valves (6, 7). The diaphragms (17, 18) are each clamped between two housing parts (11, 14; 11, 14) via a respective ring bead (22, 23) placed in a housing-side ring groove (20, 21; 20, 21). In order to avoid damaging the diaphragms (17, 18), an annular continuous or partially interrupted recess (54) is arranged in the ring groove (20, 21) or immediately adjacent to the ring groove to receive displaced bead material from the diaphragm (17).