Patent ID: 7909026

Claim:
A method of operating an engine supercharger comprising a pair of coactinq rotors adapted for rotation within a rotor housing; the rotors connected to a pair of timing gears engaged to maintain correlated rotation of the rotors in the housing; a gear case enclosing the timing gears and adapted to contain a volume of oil for lubricating the gears; and a servo-actuated drive train engaging one of the timing gears and adapted when actuated to rotate the timing gears and drive the rotors, wherein the drive train further comprises an enclosed clutch housing adjoining the gear case and adapted to contain oil for use in the clutch housing; a hydraulic clutch in the clutch housing and engaging said one of the timing gears for driving the timing gears when the hydraulic clutch is engaged; a servo oil pump within the clutch housing and hydraulically connected with the hydraulic clutch, the pump adapted when actuated to supply pressurized oil for engaging the hydraulic clutch, the pump being drivably connected with the hydraulic clutch for rotating the hydraulic clutch when the oil pump is actuated; an electromagnetic clutch external to the clutch housing and drivably connected with the hydraulic clutch for rotating the hydraulic clutch when the electromagnetic clutch is actuated; and a drive member drivably connected to the electromagnetic clutch, the electromagnetic clutch being externally controllable to rotatably connect the drive member with the oil pump and rotate the oil pump for initiating actuation and rotation of the hydraulic clutch with resultant rotation of the timing gears and the supercharger rotors; the method including: operating the engine; and mechanically driving the supercharger rotors directly from the drive member through the electromagnetic clutch, the hydraulic pump rotor, the hydraulic clutch and the timing gears to the rotors.