A compressor may include first and second scrolls, and an axial biasing chamber. Spiral wraps of the scrolls mesh with each other and form compression pockets including a suction-pressure compression pocket, a discharge-pressure compression pocket, and intermediate-pressure compression pockets. The axial biasing chamber may be disposed axially between the second end plate and a component. Working fluid disposed within the axial biasing chamber may axially bias the second scroll toward the first scroll. The second end plate includes outer and inner ports. The outer port is disposed radially outward relative to the inner port. The outer port may be open to a first one of the intermediate-pressure compression pockets and in selective fluid communication with the axial biasing chamber. The inner port may be open to a second one of the intermediate-pressure compression pockets and in selective fluid communication with the axial biasing chamber.

A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

A scroll compressor includes an orbiting scroll that is coupled to a rotating shaft in a casing and includes an orbiting end plate portion coupled to the rotating shaft and an orbiting wrap that has a spiral shape protruding from one surface of the orbiting end plate portion, a fixed scroll including a fixed wrap that is engaged with the orbiting wrap defines a compression chamber with the orbiting wrap therebetween, and a main frame that rotatably supports the orbiting scroll and defines a back pressure chamber with the orbiting scroll. The fixed scroll defines a fixed back pressure hole having a first end configured to communicate with the first back pressure chamber and a second end is located between outer and inner circumferences of the orbiting wrap. The orbiting wrap is configured to cover at least a portion of the fixed back pressure hole during the orbital motion.

A variable oil pump includes a pump housing, a cover, an oil pump rotor rotationally driven while housed in a housing space between the pump housing and the cover, an adjustment member housed in the housing space to adjust the amount of oil discharged from the oil pump rotor by being displaced due to a drive force while rotatably holding the oil pump rotor from an outer peripheral side, and a guide portion including a groove in the adjustment member and a pin on the pump housing that engage one another. Engagement of the pin and the groove guides displacement of the adjustment member relative to the pump housing. A seal structure on at least one of the pump housing and the cover seals the inside of the groove relative to the housing space by surrounding a movement trajectory of the groove relative to the pin.

A cam ring is capable of moving while rolling on a cam support surface. The cam ring is provided such that within a range in which the cam ring can move on the cam support surface, an eccentricity amount increasing-side angle is always greater than an eccentricity amount decreasing-side angle. On a plane perpendicular to the rotation axis of a driving shaft, the eccentricity amount increasing-side angle is an angle, in a direction opposite to a rotation direction of the driving shaft, from a first reference line, which connects a tangent point between the cam ring and the cam support surface to a rolling center of the cam ring, to a starting end of a first discharge port. The eccentricity amount decreasing-side angle is an angle, in the rotation direction of the drive shaft, from the first reference line to a terminal end of the first discharge port.

An object is to optimize a back pressure pressing an orbiting scroll against a fixed scroll in a scroll compressor to which an injection cycle is applied. A back pressure control valve (400) adjusting back pressure (Pm) in a back pressure chamber (H4), adjusts the opening degree of a first valve body (424) increasing and decreasing the flow rate of lubricant which has been separated from gaseous refrigerant compressed in a compression chamber and is supplied to the back pressure chamber (H4), in accordance with suction pressure (Ps) in a suction chamber (H1), discharge pressure (Pd) in a discharge chamber (H2), and injection pressure (Pinj). Then, the back pressure control valve (400) increases and decreases the lubricant flow rate in accordance with injection pressure (Pinj) as well as suction pressure (Ps) and discharge pressure (Pd), to adjust back pressure to target back pressure varying in accordance with injection pressure (Pinj).

A high pressure threshold detection circuit (100) is provided. The high pressure threshold detection circuit includes a pressure transducer (110) for measuring a pressure of a medium at an outlet (104) of a compressor (102). The high pressure threshold detection circuit (100) includes a controller (120). The controller (120) includes a comparator (123) and a switch (125). The comparator (123) and the switch (125) are electrically coupled. The switch (125) is electrically coupled to an enable circuit (131). The pressure transducer (110) is electrically coupled to the comparator (123) to provide a signal to the comparator (123) based on the pressure measured at the outlet (104). The comparator (123) outputs a control signal (111) to the switch (125) when the signal (111) is equal to or greater than a reference value (126). The switch (125) opens the enable circuit (131) to disable compression of the medium by the compressor (102) in response to the control signal (111).

A valve assembly for an electrical refrigerant compressor of a motor vehicle, comprising: a flexurally elastic valve plate for the pressure-regulated opening and closing of an outlet opening of the refrigerant compressor; and a rigid stop plate for limiting the movement of the valve plate, the stop plate and the valve plate being in the form of a preassembled component.

A control system comprising: a suction line; an exhaust line; an operating liquid line; a liquid ring pump comprising a suction input coupled to the suction line, an exhaust output coupled to the exhaust line, and a liquid input coupled to the operating liquid line; one or more regulating devices configured to control flow of the operating liquid into the liquid ring pump; a first sensor configured to measure a first parameter of an exhaust fluid of the liquid ring pump; a second sensor configured to measure a second parameter of an operating liquid received by the liquid ring pump; and a controller operatively coupled to the sensors and the regulating device(s), and configured to control the regulating device(s) based on measurements by the sensors.

A variable oil pump includes a pump housing, an oil pump rotor housed in the pump housing and rotationally driven, an adjustment member housed in the pump housing and adjusting an oil discharge amount from the oil pump rotor by being displaced due to a drive force while rotatably holding the oil pump rotor from an outer peripheral side, and a guide portion including a groove provided in the adjustment member and a pin provided on the pump housing and engaging with the groove. The guide portion guides relative displacement of the adjustment member with respect to the pump housing by engaging the groove and the pin with each other, and an inner surface of the groove and an outer surface of the pin come into line contact with each other along a direction in which the pin extends at an initial position where the adjustment member starts its displacement.