A system and method for measuring a speed of an engine are provided. The engine has a positive displacement pump drivingly connected to a rotor shaft thereof, the pump having an inlet for receiving a fluid supply and an outlet for outputting pressurized fluid. A sensor signal is received from a pressure sensing device provided at an inlet of the pump, the sensor signal comprising a series of periodic oscillations. A frequency of the oscillations is determined, the frequency proportional to a rotational speed of the rotor shaft. The speed of the engine is then determined from the frequency of the oscillations and the speed of the engine as determined is output for controlling operation of the engine.

The disclosure provides a pump device capable of suppressing hydraulic amplitude and reducing noise or vibration associated with hydraulic amplitude while simplifying the structure. The pump device includes: a housing which defines a suction port, a discharge port, and an accommodation chamber; and a pump unit which is arranged in the accommodation chamber and which defines a pump chamber that expands and contracts to exert a pumping action including a suction stroke and a pressurization and discharge stroke on a fluid. The housing includes an air introduction hole that is opened to introduce air into the pump chamber at a predetermined opening timing immediately before the suction stroke is completed.

Detection of reverse rotation or operation of a refrigerant compressor is provided. In one aspect, a detection technique includes starting the compressor and determining the compressor is rotating in a reverse direction if a dome temperature of the compressor fails to exceed a first predetermined threshold at or before expiration of a first predetermined period of time following starting, the refrigerant pressure at a refrigerant inlet of the compressor remains constant for a second predetermined period of time following starting, and/or the frequency of pressure oscillations of the refrigerant at the refrigerant inlet exceeds a second predetermined threshold. Another technique for determining the compressor is rotating in the reverse direction involves analyzing a waveform associated with motor current, motor torque, or refrigerant pressure. Further embodiments, forms, features, and aspects shall become apparent from the description and drawings.

A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger includes a first hub, a second hub, a first side coupling assembly, a second side coupling assembly, a central hub and a plurality of coupler pins. The first hub is mounted for concurrent rotation with the input shaft. The second hub is mounted for concurrent rotation with the rotor shaft. The first side coupling assembly has a first side coupling body and a first side elastomeric insert. The first side coupling body includes an inboard body portion having a first series of pockets and an outboard body portion having a second series of pockets. The first side elastomeric insert has a first and second plurality of lobes. The pockets of the first and second series of pockets are tangentially offset relative to each other and each receive respective first and second plurality of lobes therein.

A rotary compressor may include a case, a cylinder, a roller, a vane, a main bearing and a sub bearing, and a discharge passage defined in the main bearing or the sub bearing to discharge refrigerant compressed in a compression space. The discharge passage may include at least one discharge hole formed through the main bearing or the sub bearing, and at least one discharge guide groove having a first end that communicates with the at least one discharge hole and a second end that extends from the at least one discharge hole toward a contact point between the cylinder and the roller and is recessed from one surface of the main bearing or the sub bearing forming the compression space. Accordingly, an amount of refrigerant remaining in the compression space even after a discharge stroke may be reduced.

A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger includes a first hub, a second hub, a first side coupling assembly, a second side coupling assembly, a central hub and a plurality of coupler pins. The first hub is mounted for concurrent rotation with the input shaft. The second hub is mounted for concurrent rotation with the rotor shaft. The first side coupling assembly has a first side coupling body and a first side elastomeric insert. The first side coupling body includes an inboard body portion having a first series of pockets and an outboard body portion having a second series of pockets. The first side elastomeric insert has a first and second plurality of lobes. The pockets of the first and second series of pockets are tangentially offset relative to each other and each receive respective first and second plurality of lobes therein.

A rotary compressor may include a case, a cylinder, a roller, a vane, a main bearing and a sub bearing, and a discharge passage defined in the main bearing or the sub bearing to discharge refrigerant compressed in a compression space. The discharge passage may include at least one discharge hole formed through the main bearing or the sub bearing, and at least one discharge guide groove having a first end that communicates with the at least one discharge hole and a second end that extends from the at least one discharge hole toward a contact point between the cylinder and the roller and is recessed from one surface of the main bearing or the sub bearing forming the compression space. Accordingly, an amount of refrigerant remaining in the compression space even after a discharge stroke may be reduced.

A scroll compressor may include a first scroll and a second scroll orbiting relative to the first scroll to form compression chambers, a discharge port provided in the first scroll to discharge refrigerant compressed in the compression chamber, a discharge passage formed through the first discharged through the discharge to an upper side of the frame, and a discharge cover coupled to the first scroll and having a space to accommodate end portions of the discharge port and the discharge passage to guide the refrigerant discharged through the discharge port to the discharge passage. A volume of a discharge space defined in the space by the first scroll may be 4.5 or more, obtained by dividing a volume of the discharge space by a total volume of an initial compression chamber among the compression chambers.

A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger includes a first hub, a second hub, a first side coupling assembly, a second side coupling assembly, a central hub and a plurality of coupler pins. The first hub is mounted for concurrent rotation with the input shaft. The second hub is mounted for concurrent rotation with the rotor shaft. The first side coupling assembly has a first side coupling body and a first side elastomeric insert. The first side coupling body includes an inboard body portion having a first series of pockets and an outboard body portion having a second series of pockets. The first side elastomeric insert has a first and second plurality of lobes. The pockets of the first and second series of pockets are tangentially offset relative to each other and each receive respective first and second plurality of lobes therein.

In a hydraulic control device, when it is detected that a pressure of first oil (output pressure) detected by an output pressure sensor pulsates, a transmission control unit as a TCU stops driving of a second pump or decreases a rotation number of the second pump as a first operation. Alternatively, when it is detected that the output pressure pulsates, the TCU increases the rotation number of the second pump to a rotation number (for example, maximum rotation number) that is higher than a target rotation number as a second operation.