Patent ID: 6928969

Claim:
A method of operating an engine having a cylinder, an intake valve associated with the cylinder and moveable between a first position where the intake valve prevents a flow of fluid relative to the cylinder and a second position where the intake valve allows a flow of fluid relative to the cylinder, a cam assembly connected to the intake valve to move the intake valve between the first and second positions, and a fluid actuator connected to the intake valve, comprising: sensing at least one operating parameter of the engine; operating the engine in a first mode wherein the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near a top dead center position of an intake stroke and wherein the cam assembly returns the intake valve to the first position when the piston is at or near a bottom dead center position of the intake stroke, the engine operating in the first mode in response to the sensed operating parameter being at one of a predetermined first set of conditions; and operating the engine in a second mode wherein the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near a top dead center position of an intake stroke and wherein the fluid actuator prevents the intake valve from returning to the first position in response to the cam assembly, the engine operating in the second mode in response to the sensed operating parameter being at one of a predetermined second set of conditions.