An electric oil pump includes: a pump unit 2, rotating to make oil flow; a motor 3 driving the pump unit; a control unit 4 exerting driving control on the motor; and a housing 1 accommodating the pump unit, the motor, and the motor control unit. In the electric oil pump, the motor control unit 4 directly receives detection information of a temperature sensor 5 detecting a temperature of the oil and exerts driving control on the motor based on the detection information.

The present invention provides an oil pump device capable of preventing foreign matters from getting caught at a sliding part of an oil pump, and thus of preventing a situation where the oil pump is locked and prevented from rotating. The oil pump device includes an oil pump connected to a supply target apparatus by a hydraulic circuit, the oil pump discharging and supplying oil to the supply target apparatus through the hydraulic circuit; a motor driving the oil pump; a trapping member interposed along the hydraulic circuit, the trapping member trapping a foreign matter mixed in the oil discharged from the oil pump; and a motor control unit controlling the motor to perform a normal control mode of driving the oil pump in a normal control rotation range and perform, at operational start of the oil pump, a lock-avoiding mode of driving the oil pump with a lock-avoiding rotational speed set in advance as a lower limit.

A method, system, and computer-readable medium related to control of mud motors in drilling systems, of which the method includes measuring an eccentricity of rotation of a rotor in a stator of a mud motor using a rotor-position sensor, determining a torque of the mud motor based in part on the eccentricity, and selecting a fluid flow rate, a pressure, or both of fluid delivered downhole, through the mud motor, based in part on the determined torque.

A method for controlling the rotational speed (S) of an electric motor driven air compressor (2) that supplies compressed air to a pneumatically operated system (5) of a vehicle (1), characterized by the preliminary steps of: a) determining the efficiency (e) of the air compressor (2) for different values (Si) of the rotational speed (S) of the air compressor (2), the efficiency (e) of the air compressor (2) corresponding to the ratio between the pneumatic power (PI) produced by the air compressor (2) and the power (PO) given to the air compressor (2); b) determining one or several specific values (S2, S4) among said different values (Si), for which the efficiency (e) of the air compressor (2) is higher than a threshold value (emin) and/or comparatively higher than those determined for values (SI, S3) close to said specific value(s) (S2, S4); the preliminary steps a) and b) being preferably implemented only once; and characterized by the further repetitive steps of: c) determining the air consumption rate of the pneumatically operated system (5) receiving compressed air from the air compressor (2); d) determining a minimum rotational speed (Smin) of the air compressor (2) to obtain an air production rate of the air compressor (2) that is equal or substantially equal to said determined air consumption rate; e) determining if the specific value or one of the specific values (S2, S4) is greater than said determined minimum rotational speed (Smin); f) if no specific value is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said minimum rotational speed (Smin); g) if only one specific value (S4) is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said only one specific value (S4); h) if a plurality of specific values (S2, S4) is greater than said determined minimum rotational speed (Smin), determining the specific value (S2) with the best efficiency among said plurality of specific values (S2, S4) and controlling the rotational speed (S) of the air compressor (2) based on said specific value (S2) with the best efficiency.

The invention relates to an orbital pump for pumping a fluid, wherein the pump comprises at least one pump control system, a motor that can be controlled by the pump control system, a rotor shaft (10) for fluid transport, and a rotor sensor for detecting an absolute angle of rotation of the rotor shaft (40), the rotor sensor is connected to the pump control system and designed to transmit the angle of rotation of the rotor shaft (40) to the pump control system, and the pump control system is designed to rotationally control the rotor shaft (40) by means of the motor until the rotor shaft (40) is in a pre-determined angle of rotation position.

A pump with variable suction/discharge amount and a transmission drive device and a driving method thereof. The pump is a rotary vane pump having a vane chamber body. The vane chamber body is composed of a fixed wall member, a movable wall member, a movable vane chamber sleeve and a vane rotor. The vane chamber is extendable/retractable in an axial direction of the vane rotor. At least two pumps are assembled in communication with each other to form a closed loop for the active pump to drive the passive pump. In operation, passive the vane chambers of the active pump and the passive pump are automatically extended/retracted and modulated until the driving force and the load resistance achieve a balanced state passive, the vane chambers and the rotational speeds of the active pump and the passive pump are automatically adjusted to be in inverse proportion to each other.

A driving force distributing device includes a single pump for supplying control hydraulic pressure to each of first and second hydraulic clutches, an electric motor for driving the pump, a flow rate variable mechanism for changing a ratio of flow rate of hydraulic fluid supplied to each of the first and second hydraulic clutches and a controlling means for controlling the electric motor and the flow rate variable mechanism. The driving force distributing device can variably control a flow rate of hydraulic fluid supplied to first and second hydraulic clutches based on changing a ratio of flow rate of hydraulic fluid supplied to the first and second hydraulic clutches in the flow rate variable mechanism and a control of changing rotational speed of the pump using the motor.

A method of operating an exhaust gas recirculation pump for an internal combustion engine including: providing an EGR pump assembly including an electric motor coupled to a roots device having rotors, the EGR pump operably connected to an internal combustion engine; providing an EGR control unit lined to the EGR pump assembly; providing sensors linked to the EGR control unit; determining if a motor speed is within a predetermined target (step SI), wherein when the motor speed is within the predetermined target then; determining if a motor torque is within a predetermined target (step S2) wherein when the motor torque is within the predetermined target then; determining if a motor temperature is within a predetermined target (step S3) wherein when the motor temperature is within the predetermined target then; maintaining operation of the exhaust gas recirculation pump.

The control section controls the electric motor to be driven such that the number of revolutions becomes equal to the target number of revolutions. If the control section sets the target number of revolutions to a number of revolutions of the electric motor requested by another control section, the control section changes the number of revolutions of the electric motor at an increase rate lower than or equal to the upper limit value of the increase rate or at a decrease rate lower than or equal to the upper limit value of the decrease rate. If the control section sets the target number of revolutions to a number-of-revolutions limit value, which is determined based on the voltage of a vehicle battery, the control section is able to decrease the number of revolutions of the electric motor at a decrease rate exceeding the upper limit value.

The present disclosure relates to a dual-stage compressor, a control method thereof, and an air conditioning unit. The dual-stage compressor includes a low-pressure stage; a high-pressure stage connected in series with the low-pressure stage; and a volume ratio adjustment mechanism arranged at the high-pressure stage and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage. When the final compression pressure of the compressor is lower or greater than the exhaust pressure, the volume ratio adjustment mechanism is operated to increase or reduce the volume ratio of refrigerant compression at the high-pressure stage so that the final compression pressure of the compressor is equal to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.