Patent ID: 8191520

Claim:
A variable valve operating apparatus for an internal combustion engine, comprising: a first camshaft to which a first cam for driving a first valve in a cylinder of the internal combustion engine is attached fixedly or movably in an axial direction; a second camshaft to which a second cam for driving a second valve disposed in the same cylinder as that of the first valve is attached fixedly or movably in an axial direction; a guide rail which is provided in an outer peripheral surface of a cylindrical part which is attached fixedly or movably in the axial direction respectively to the first and second camshafts; a projection part which is disposed so as to be engageable and disengageable with the guide rail; and an actuator which is disposed so as to oppose the cylindrical part, and is able to protrude the projection part toward the guide rail, wherein valve-opening characteristics of the first valve and the second valve are changed as a relative displacement between the projection part and the cylindrical part takes place at a time of engagement between the projection part and the guide rail, and wherein in a state in which the projection part is not protruded toward the guide rail, at least a part of the actuator is disposed so as to fit in an oval-shaped region seen from the axial direction of the first and second camshafts, the oval-shaped region being virtually obtained by linking: a circle of the larger of a circle diameter of the cylindrical part and a base circle diameter of the first cam which are attached to the first camshaft; and a circle of the larger of a circle diameter of the cylindrical part and a base circle diameter of the second cam which are attached to the second cam.