In one featured embodiment, a closure sleeve for a valve comprises a sleeve body surrounding a center axis and defined by an overall length extending from an upstream end to a downstream end. The sleeve body has an internal cavity that is enclosed at the downstream end and is open at the upstream end. The internal cavity is defined in part by a piston contact surface that is defined by an inner diameter. The piston contact surface is configured to slide against a piston to be received within the internal cavity, and a ratio of the inner diameter to the overall length is between 1.0 and 1.5.

A compressor is disclosed. In one aspect, the compressor includes a pressure chamber which is delimited by at least two housing parts, the housing parts including sealing surfaces that are connected by a connection device which applies a contact pressing force between the sealing surfaces. At least one groove extending in a circumferential direction is arranged on at least one sealing surface. At least one relief opening is arranged on at least one of the housing parts. The relief opening connects the groove to the surroundings of the compressor and emanates from the groove. The groove is arranged such that when a predetermined maximum pressure is exceeded in the pressure chamber, a pressure-building medium can gather in the groove and at least partially escape through the relief opening.

A compressor is disclosed. In one aspect, the compressor includes a pressure chamber which is delimited by at least two housing parts, the housing parts including sealing surfaces that are connected by a connection device which applies a contact pressing force between the sealing surfaces. At least one groove extending in a circumferential direction is arranged on at least one sealing surface. At least one relief opening is arranged on at least one of the housing parts. The relief opening connects the groove to the surroundings of the compressor and emanates from the groove. The groove is arranged such that when a predetermined maximum pressure is exceeded in the pressure chamber, a pressure-building medium can gather in the groove and at least partially escape through the relief opening.

A system comprises a variable displacement pump, a metering valve, a bypass line, a pressure regulating valve, a position sensor, and a control system. At least one fuel nozzle can be in fluid communication with the output line downstream of the metering valve, wherein the variable displacement pump is configured to supply fuel to the at least one fuel nozzle. The metering valve can be disposed in the output line for controlling outlet flow from the variable displacement pump. The system can also include an actuator line parallel to the variable displacement pump and connected to the output line to provide actuation pressure from pump output of the variable displacement pump.

An air compression pump includes a pump head and a pumping device fluidly connected with the pump head. The pumping device includes a cylinder fixed to the pump head. Further, a relief valve is fluidly connected with and received by the pump head. The relief valve defines a relief hole which is fluidly communicable with the first cylinder. The relief valve includes a valve body selectively closing the relief hole. The valve body is movable to an open position to relieve pressure in the air compression pump by allowing pressurized air to flow out of the air compression pump through the relief hole.

A compressor (10) for compressing air for a compressed air system of a motor vehicle has a cylinder housing (14) and a cylinder head (16) connected thereto. A compressor piston is moveable in oscillation up and down in a cylinder in the cylinder housing (14). A lamella (34, 36) is received in a depression (38) in an underside (30) of the cylinder head (16) facing the compressor piston. The delivery rate of the compressor (10) can be regulated by closing or opening a control channel (60, 60′) in the cylinder head (16) via the lamella. A bearing end (44) of the lamella (34, 36) is hinged in a pivotably guided manner on a bearing contour (54) of this depression (38). As a result, a separate bearing journal for pivotable mounting of the lamella (34, 36) on the cylinder head (16) may be omitted.

A compressor (10) for compressing air for a compressed air system of a motor vehicle has a cylinder housing (14) and a cylinder head (16) connected thereto. A compressor piston is moveable in oscillation up and down in a cylinder in the cylinder housing (14). A lamella (34, 36) is received in a depression (38) in an underside (30) of the cylinder head (16) facing the compressor piston. The delivery rate of the compressor (10) can be regulated by closing or opening a control channel (60, 60′) in the cylinder head (16) via the lamella. A bearing end (44) of the lamella (34, 36) is hinged in a pivotably guided manner on a bearing contour (54) of this depression (38). As a result, a separate bearing journal for pivotable mounting of the lamella (34, 36) on the cylinder head (16) may be omitted.

An air system and method includes an air compressor, a temperature sensors, a valve, and a controller. The air compressor is configured to receive filtered air. The temperature sensor is positioned at or near an outlet of the air compressor and configured to sense a temperature at or near the outlet of the air compressor. The valve is operatively connected to an outlet of the air compressor and external to the air compressor. The controller is configured to monitor the sensed temperature at the outlet of the air compressor and control the valve to permit air to flow from the outlet of the air compressor through the valve to unload the air compressor if the sensed temperature exceeds a threshold temperature.

An air system and method includes an air compressor, a temperature sensors, a valve, and a controller. The air compressor is configured to receive filtered air. The temperature sensor is positioned at or near an outlet of the air compressor and configured to sense a temperature at or near the outlet of the air compressor. The valve is operatively connected to an outlet of the air compressor and external to the air compressor. The controller is configured to monitor the sensed temperature at the outlet of the air compressor and control the valve to permit air to flow from the outlet of the air compressor through the valve to unload the air compressor if the sensed temperature exceeds a threshold temperature.

A compressor installation having a reduced load at start-up, including a gas compressor having an inlet and an outlet and a start-up valve connected to the outlet of the compressor. The start-up valve includes a valve body having an inlet and an outlet, a valve plunger connected to the inlet of the valve body, a spring connected to the valve body and the valve plunger, and a muffler. The start-up valve is configured to discharge the compressed gas through the muffler to atmosphere to reduce the load on the motor at start-up. After starting the compressor, the spring in the start-up valve is compressed after pressure is increased by the compressor and the discharge through the start-up valve to atmosphere is closed.