A control valve (3) of a compressed air system of a vehicle has a control piston (22), guided in an axially movable manner in a housing cylinder (25), two pressure chambers (32, 34) separated from one another by the control piston (22), which is sealed by at least one sealing ring (37) arranged on the outer circumference of the control piston (22). The sealing ring (37) is a radial sealing ring having an axial length which substantially corresponds to the axial thickness of the control piston (22). The sealing ring (37) has, on each of the two axial edges thereof, one respective radially obliquely outwardly directed sealing lip (39, 40) which is in contact with the inner wall (38) of the cylinder (25), and that a plurality of guide members (50) distributed over the circumference and formed between the two sealing lips (39, 40) on the sealing ring (37).

An electric-parking-brake for a utility-vehicle, including: a feed-line for brake-pressure air; a discharge-line for brake-pressure air for a pneumatic-brake-device; a first-valve and a second-valve, each being switchable between a stable-state and an activated-state in response to electrical control-signals; and a valve-device which is connected between the feed-line and the discharge-line and exhibits a control-input, the valve device being switchable between a stable-state and an activated-state in response to control signals at the control-input, the feed-line being connected to the discharge-line in the activated-state, in which the first-valve in the stable-state or in the activated-state connects the control-input of the valve-device to the discharge-line, to retain a current-state of the valve-device when the brake-pressure air is applied to the discharge-line, and in the activated or stable state connects the control-input to the second-valve. Also described are an electric parking brake system, a utility vehicle, and a related method.

An electropneumatic control module for an electronically controllable pneumatic brake system for a vehicle combination with a tractor vehicle and a trailer vehicle includes a pneumatic reservoir input, which is connectable to a compressed-air reservoir, and a trailer control unit, which has a trailer control valve unit with one or more electropneumatic valves, a trailer brake pressure port and a trailer supply pressure port. The electropneumatic control module further includes an immobilizing brake unit, which has a spring-type actuator port for at least one spring-type actuator for a tractor vehicle and an immobilizing brake valve unit with one or more electropneumatic valves, and an electronic control unit, wherein the electronic control unit is designed to, based on an electronic immobilizing signal, trigger the immobilizing brake valve unit to switch at least one valve of the immobilizing brake valve unit.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A control valve (3) of a compressed air system of a vehicle has a control piston (22), guided in an axially movable manner in a housing cylinder (25), two pressure chambers (32, 34) separated from one another by the control piston (22), which is sealed by at least one sealing ring (37) arranged on the outer circumference of the control piston (22). The sealing ring (37) is a radial sealing ring having an axial length which substantially corresponds to the axial thickness of the control piston (22). The sealing ring (37) has, on each of the two axial edges thereof, one respective radially obliquely outwardly directed sealing lip (39, 40) which is in contact with the inner wall (38) of the cylinder (25), and that a plurality of guide members (50) distributed over the circumference and formed between the two sealing lips (39, 40) on the sealing ring (37).

A relay valve is provided for a vehicle. The valve includes a parking brake piston that is displaceable in a housing and an axially displaceable cuff, a first compressed-air chamber for receiving compressed air from a control line is formed between the parking brake piston and the housing. The valve is also provided with a first spring element, which axially applies a pre-loading force to the cuff, and with a second spring element, which axially applies another pre-loading force to the parking brake piston. An axially displaceable service brake piston is arranged axially between the parking brake piston and the cuff, the service brake piston rests at least radially against the parking brake piston and radially against the housing in a sealing manner, in order to form a second compressed-air chamber.

A brake modulator (1) for a compressed air braking system (80) of a vehicle is disclosed. The brake modulator (1) has a main housing (8) and two relay valves (2, 3). Each relay valve is configured with a delivery valve seat (31, 131) and a vent valve seat (30, 130) and a vent position, wherein compressed air inlets (2d, 3d) are connected via a transverse bore (27) to a common compressed air inlet port (25, 26), and a delivery duct (12a, 112a) extends in the axial direction (A) in each relay valve (2, 3). The relay valves (2, 3) have guide body inserts (12, 112) which are inserted into a longitudinal bore (29) of the main housing (8), which longitudinal bore (29) extends in the axial direction (A), and the relay valves (2, 3) in each case have the delivery duct (12a, 112a).

A valve arrangement (14.2) of a tractor vehicle (2) for controlling a pneumatic brake system of a trailer vehicle (4) includes a trailer control valve (16) with a reservoir pressure input (p11) for the introduction of reservoir compressed air and a reservoir pressure output (p21) for the controlled discharge of reservoir compressed air. The reservoir pressure output is pneumatically connected to a reservoir coupling head (6) of the tractor vehicle. A shut-off and ventilation valve (98) is arranged in a reservoir pressure line (48) upstream of the reservoir coupling head. Before connecting an associated coupling head of the trailer vehicle (4) to the reservoir coupling head of the tractor vehicle, the feed of reservoir compressed air to the reservoir coupling head can be shut off to ventilate the reservoir coupling head. After reconnecting the associated coupling head, the reservoir coupling head can be charged again.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A valve system includes a control module on a tractor portion of a vehicle adapted to receive a supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal. A supply glad-hand fluidly communicates the selectively transmitted supply pressure of the pneumatic fluid to supply a brake on an associated trailer portion of the vehicle. A control glad-hand fluidly communicates the control module delivery pressure of the pneumatic fluid to control the brake on the associated trailer portion of the vehicle. An exhaust valve, which fluidly communicates with both the selectively transmitted supply pressure and the control module delivery pressure, exhausts the control module delivery pressure of the pneumatic fluid from the control glad-hand.