A method of controlling an engine is provided. At least one operating parameter
of the engine is sensed. The engine is operated in a first mode in response to
the sensed operating parameter being at one of a predetermined first set of conditions.
In the first mode, a cam assembly moves an intake valve from a first position when
a piston starts an intake stroke and the cam assembly returns the intake valve
to the first position when the piston completes the intake stroke. The engine is
operated in a second mode in response to the sensed operating parameter being at
one of a predetermined second set of conditions. In the second mode, the cam assembly
moves the intake valve from the first position when the piston starts an intake
stroke and an actuator prevents the intake valve from returning to the first position
in response to the cam assembly.