Patent ID: 6971350

Claim:
A variable valve control system for an internal combustion engine including a plurality of cylinders and a plurality of intake valves each for an associated one of the cylinders, the variable valve control system comprising: a variable lift characteristic control mechanism to adjust a valve lift characteristic of each of the intake valves; a sensing section to collect information needed to determine an engine condition indicator in correlation with an actual relative variation in the valve lift characteristic between the cylinders; and a control unit in operative communication with the variable lift characteristic control mechanism and the sensing section, to perform the following: determining a desired valve lift characteristic in accordance with an operating condition of the internal combustion engine; controlling the valve lift characteristic of each of the intake valves in accordance with the desired valve lift characteristic; determining the engine condition indicator when the desired valve lift characteristic is equal to a predetermined small valve lift characteristic setting; and expanding the small valve lift characteristic setting if the determined engine condition indicator is larger than a predetermined first threshold value.