The present invention controls convergent pressure of a closed space provided with a fluid resistance at high speed while an upstream valve provided on the upstream of the fluid resistance prevents overshooting. A pressure control system is provided with a fluid resistance in a channel forming a closed space and is configured to control pressure of the closed space by controlling an upstream valve provided on the upstream of the fluid resistance. The pressure control system includes a convergent pressure arithmetic unit and a valve controller. The convergent pressure arithmetic unit calculates convergent pressure of the closed space when the upstream valve is fully closed using at least one of upstream pressure and downstream pressure on the fluid resistance in the channel. The valve controller compares the calculated convergent pressure with a predetermined target convergent pressure and fully close the upstream valve based on the result of the comparison.

A vacuum system includes at least a first vacuum valve, a second vacuum valve, a pressure sensor connected to the vacuum volume to determine an actual pressure in a vacuum volume, and a regulation and control unit connected to the first vacuum valve, to the second vacuum valve and to the pressure sensor. The regulation and control unit is configured to regulate the actual pressure based on a predetermined target pressure, with continuous detection of the actual pressure, a determination of a negative pressure or a positive pressure as the first pressure deviation based on the detected actual pressure and the predetermined target pressure, an opening of the first or the second vacuum valve to reduce the first pressure deviation, a monitoring of the first pressure deviation, a determination of a second pressure deviation, an additional opening of the other vacuum valve to reduce the second pressure deviation.

An air control circuit including a safety function is simply formed from an air circuit. An air control circuit includes a main air line that controls an air device by concurrently turning on or off two external-pilot-operated electromagnetic valves, a pilot air line that supplies pilot air to the electromagnetic valves, and a pilot control line that switches the pilot air line between a supply state and an exhaust state. When one of the two electromagnetic valves suffers a breakdown to fail to be switched to an off position, air in the air device is exhausted through the other electromagnetic valve that has been switched to the off position to recover the air device, and the pilot air line is switched to the exhaust state by the pilot control line to prevent the two electromagnetic valves from restarting.

The invention relates to a pressure control device, consisting of at leasttwo switching valves (10, 12), a feedback control unit (14), a sensor unit (20), and a voltage supply unit (24).

This disclosure relates generally to valves, and more particularly, to gas valve assemblies. In one example, the valve assembly may include a valve body with a fluid path, one or more valves or valve sealing members positioned across the fluid path, and one or more pressure sensors in fluid communication with a fluid path of the valve assembly. The valve assembly may include a valve controller in communication with the pressure sensors, where the valve controller may be configured to compare a measure related to a pressure sensed by the one or more pressure sensors to a pressure threshold value (e.g., a high pressure threshold value, a low pressure threshold value, or other pressure threshold value). If the measure surpasses the threshold value, the valve controller may provide a predetermined output signal indicating a pressure event has occurred, such as a high or low gas pressure event.

An electropneumatic proportional flow control device improves electropneumatic control of pneumatically operated valves. A single integrated valve incorporates a proportional valve component in operational and physical coordination with a pressure regulator valve component. The flow path of fluid is initially passed through the regulator component whereby pressure is regulated to within a manageable range for operation of a balanced type proportional valve component.

A method of decreasing tire pressure includes opening a wheel valve (22) to allow pressurized air from a tire (10) to be directed to a first valve assembly (14) and to atmosphere. A target pressure is selected for a fluid control conduit (28). The fluid conduit (28) is in fluid communication with the first valve assembly (14) and a second or control valve assembly (30). The pressure in the fluid conduit (28) is measured. If the measured pressure is greater than the target pressure, then the second valve assembly (30) is de-energized. If the measured pressure is less than the target pressure, then the second valve assembly (30) is energized. A valve (42) prone to leak under very low temperatures may be subjected to repeated cycles of pressure application and pressure release in order to form a fluid-tight seal.

An automatic pressure regulating valve for multiple levels of driving automation of a commercial vehicle includes an upper valve body, a lower valve body, a piston, a main valve core assembly, a switching valve, a quick-acting intake valve, and a quick-acting exhaust valve. The switching valve, the quick-acting intake valve and the quick-acting exhaust valve are all mounted at an upper end of the upper valve body. The piston is located in a chamber formed by the upper valve body and the lower valve body to divide the chamber into an upper control chamber and a lower chamber. The main valve core assembly is mounted in the lower valve body. The automatic pressure regulating valve is applicable to a commercial vehicle allowing for multiple levels of driving automation.

This disclosure relates generally to valves, and more particularly, to gas valve assemblies. In one example, a gas valve assembly may include a valve body with one or more valves movable between an opened position and a closed position, one or more valve actuators configured to operate the valves, and one or more pressure sensors to sense a pressure within a fluid path of the valve assembly. A valve controller may receive a measure related to a sensed pressure from the one or more pressure sensor(s). The valve controller may compare the received measure related to the sensed pressure to an overpressure threshold. In the event the measure related to the sensed pressure surpasses the overpressure threshold value, the valve controller may be configured to provide a signal that indicates an overpressure event has occurred.

A fuel cell comprising a fuel pressure regulator apparatus on a fuel input line of the fuel cell, the apparatus comprising a first and a second valve connected in series by a fluid flow path defining an open volume between the two valves a pressure monitor device downstream of the second valve; and a controller connected to each valve for opening and closing each valve in a pulsed manner.