A system controlling pressure in a transmission including a variable displacement pump, a circuit carrying fluid from the pump to the transmission, a valve using fluid in said circuit to regulate pressure that controls displacement of the pump, a source of control pressure including an accumulator, a first spring acting with said source causing the valve to change the regulated pressure, and a second spring acting with feedback pressure from said circuit to oppose said change.

A variable displacement vane pump and a power steering can secure a discharge flow rate when a steering wheel is turned, and restrict the discharge flow rate when the steering wheel is not turned. In the variable displacement vane pump and power steering system, a bypass line is formed. The bypass line causes a hydraulic fluid in a high pressure chamber of a control valve, which controls an eccentricity of a cam ring, to flow directly to a low pressure chamber side of the control valve. The hydraulic fluid flows directly to the low pressure chamber side of the control valve when the steering wheel is turned.

A vehicle hydraulic device is provided with an electric motor-driven oil pump and a shuttle valve, so that a vane pump operates smoothly, even at the start, with a backpressure applied from the electric motor-driven oil pump to the vanes. Even when the oil pressure of a working fluid discharged from the vane pump exceeds the backpressure inside vane housing grooves, the working fluid flows from a vane pump discharge oil passage to a backpressure oil passage, so that the vanes are not pushed into the housing grooves. Thus, it is possible to reduce the fluctuations in discharge amount of the vane pump due to fluctuations in oil pressure of the vane pump discharge oil passage during operation of the vane pump.

A compressor includes a housing, a partition, a first scroll, a second scroll, and a valve assembly disposed within the second scroll. The valve assembly includes a valve housing, a valve body, and a first biasing member configured to displace the valve body from a first position to a second position relative to the valve housing. When in the first position, the valve body inhibits fluid communication between a fluid source and one of a series of compression pockets formed by the first and second scroll. When in the second position, the valve body allows fluid communication between the conduit and one or more of the series of compression pockets. The valve body is displaceable between the first and second positions in response to a change in operating temperature of the compressor.

A variable displacement pump including a control mechanism shiftable between first and second states, when the control mechanism is in the first state, the spool is in an initial position in which fluid communication between an introduction port and the remaining ports is restrained, fluid communication between a first control port and a drain port is allowed, and fluid communication between a second control port and the drain port is restrained, and when the control mechanism is shifted to the second state in accordance with increase in fluid pressure discharged, the spool is in an operating position in which the fluid communication between the introduction port and the first control port is allowed, the fluid communication between the first control port and the drain port is restrained, and the fluid communication between the second control port and the drain port is allowed.

A device for controlling a fluid mass flow for a device for compressing a gaseous fluid from a low to a high pressure level. The device has a housing with fluid connections at different pressure levels, and a closure element arranged to move in a translatory manner within the housing along a longitudinal axis, with effective surfaces assigned to the fluid connections. The closure element regulates a flow cross-section of a flow path extending between a first and a second fluid connection. The device has a receiving element for receiving the closure element. A primary segment is arranged to be completely surrounded by the receiving element as a first section of the closure element and a secondary segment is arranged to be completely surrounded by the housing as a second section of the closure element and the receiving element is arranged to be completely surrounded by the housing.

A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. An electromechanical actuator (EMA) is operatively connected to actuate the variable displacement mechanism. A flow sensing valve (FSV) connected in the outlet line. The FSV includes a sensor configured to generate sensor data indicative of flow out of the outlet line. A controller is operatively connected to the EMA to control the variable displacement mechanism based on the sensor data to support flow demands from one or more downstream systems.

The application relates to a compressed air station comprising at least two compressed air components that yield waste heat, wherein each compressed air component is designed either as a compressor, in particular as a screw compressor, or as a refrigeration dryer, wherein at least one of the compressed air components, namely a refrigeration dryer (12), is connected to the exhaust air duct (13), and wherein a further compressed air component is connected to the same exhaust air duct (13), wherein a compressed air refrigeration heat exchanger (23) is provided within the refrigeration dryer (12), in which the compressed air is cooled by way of a refrigerant conducted in a refrigerant circuit (24), wherein the refrigerant circuit (24) comprises a refrigerant compressor (25), a condenser (26), an expansion valve (27) and the compressed air refrigeration heat exchanger (23), wherein the compressed air station further comprises a dryer exhaust air duct (15), which is provided for discharging a cooling air flow that is conducted through the refrigeration dryer (12), and which connects a cooling air outlet (19) of the refrigeration dryer (12) to a refrigeration dryer connection (16) on the exhaust air duct (13), wherein the refrigeration dryer (12) has a fan (20) with a speed-adjustable fan motor (21), and the fan (20) is designed to convey the cooling air flow even against a backpressure currently prevailing in the exhaust air duct (13), wherein the refrigeration dryer (12) has a flow sensor (30) for detecting a respective current value for the cooling air volume flow V.sub.act, and wherein the refrigeration dryer (12) has a controller (22) or interacts with a controller (22), which is configured and designed to record and process the data from the flow sensor (30) and to actuate the fan motor (21) of the fan (20) in such a way that, regardless of the current backpressure in the exhaust air duct (13), the respective current cooling air volume flow V.sub.act follows a setpoint for the cooling air volume flow V.sub.soll.