Patent ID: 7255077

Claim:
A variable camshaft timing phaser for an internal combustion engine having at least one camshaft comprising: a housing having an outer circumference for accepting drive force; a rotor for connection to the camshaft coaxially located within the housing, the housing and the rotor defining at least two vanes separating chambers in the housing into advance chambers and retard chambers; a plurality of vanes in the chambers defined by the housing, wherein at least one vane is cam torque actuated and at least one other vane is oil pressure actuated, wherein the cam torque actuated vane defines a cam torque actuated advance chamber and a cam torque actuated retard chamber between the cam torque actuated vane and the housing and the oil pressure actuated vane defines an oil pressure actuated retard chamber having an exhaust line and an oil pressure actuated advance chamber and between the oil pressure actuated vane and the housing; a spool valve located along a rotational axis of the phaser comprising a spool having a plurality of lands slidably received in a sleeve in the rotor, a central passage extending between the a first land and a third land, and a spring biasing the spool, the sleeve having a first end coupled to a control pressure line from a regulated pressure valve control system and a second end vented to atmosphere, the regulated pressure valve control system including a supply input for receiving pressurized fluid from a supply, a control pressure output, and an exhaust output; wherein when the phaser is in a retard position, fluid is routed from the cam torque actuated advance chamber to the cam torque actuated retard chamber and wherein the force of the spring biasing the spool is greater than the control pressure output, and the control pressure output is routed back to the regulated pressure valve control valve and to the exhaust output; and wherein when the phaser is in an advance position, fluid is routed from the cam torque actuated retard chamber to the cam torque actuated advance chamber and wherein the control pressure output from the regulated pressure valve control system is greater than the spring biasing the spool, and fluid from a supply of pressurized fluid is routed through the central passage to the oil pressure actuated advance chamber.