Patent ID: 7600496

Claim:
A valve operating apparatus for an internal combustion engine that includes a first group of cylinders and a second group of cylinders and at least one engine valve for each of the cylinders in the first and second groups, the valve operating apparatus comprising: a drive cam fixed to a shaft which is rotated in synchronization with a crankshaft of the engine; a swing cam disposed so as to be swingable about an axis; a motion transmission mechanism operative to convert torque of the drive cam to a swing motion of the swing cam; and a valve actuating member which operates the engine valve to be open and closed in association with the swing motion of the swing cam; the drive cam, the swing cam, the motion transmission mechanism and the valve actuating member being disposed for each of the cylinders in the first and second groups, wherein the swing cam is one of a first swing cam for the first group of cylinders and a second swing cam for the second group of cylinders, the motion transmission mechanism is one of a first motion transmission mechanism for the first group of cylinders and a second motion transmission mechanism for the second group of cylinders, and the valve actuating member is one of a first valve actuating member for the first group of cylinders and a second valve actuating member for the second group of cylinders, wherein the first and second swing cams are provided with identical swing motion characteristic with respect to a rotation angle of the drive cam through the first and second motion transmission mechanisms, wherein the first swing cam and the first valve actuating member cooperate with each other to provide a valve lift amount of the engine valve for the first group of cylinders with respect to a swing angle of the first swing cam, which is identical to a valve lift amount of the engine valve for the second group of cylinders with respect to a swing angle of the second swing cam, and wherein the first swing cam and the second swing cam have cam profiles different from each other.