Patent ID: 7325521

Claim:
A system for regulating flow to a cylinder of an internal combustion engine, the system comprising: a valve operating mechanism capable of opening at least one intake valve at an opening position that is after top-dead-center, relative to an intake stroke of a cylinder, said intake valve opening position also being in advance of a closing of an exhaust valve in said cylinder; a cam profile switching device that is capable of changing the amount of intake valve lift produced by said valve operating mechanism; and a controller constraining cam retard so that a desired level of manifold vacuum is observed when said cam profile switch is in a low lift position and when said valve operating mechanism is in a retarded position wherein the opening of said at least one intake valve is after top-dead-center, relative to the intake stroke of said cylinder, and where the opening of said at least one intake valve is in advance of the exhaust valve closing in said cylinder.