Patent ID: 7040277

Claim:
A cylinder operation control apparatus comprising: an internal combustion engine which is adapted to operate in an all-cylinder activation mode in which all-cylinders thereof are activated, and in a cylinder deactivation mode in which at least a cylinder thereof is deactivated; a lift amount changing device which is associated with the internal combustion engine, and which enables switching between the all-cylinder activation mode and the cylinder deactivation mode by changing the amount of lifts of intake and exhaust valves associated with the cylinders; a lift operating device which is associated with the lift amount changing device to operate the same; a cylinder activation enforcing device which is operatively disposed between the lift amount changing device and the lift operating device so as to enforce the all-cylinder activation mode as necessary; and a control unit which is operatively connected to the lift amount changing device, the lift operating device, and the cylinder activation enforcing device, for controlling the operation mode of the internal combustion engine.