Valve operating apparatus for internal combustion engine

A valve operating apparatus for a V-type internal combustion engine that includes a first group of cylinders and a second group of cylinders which are arranged in a generally V-shape 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 valve actuating member including a cam follower which follows 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 includes a first swing cam for the first group of cylinders and a second swing cam for the second group of cylinders, and the motion transmission mechanism includes a first motion transmission mechanism for the first group of cylinders and a second motion transmission mechanism for the second group of cylinders,
• wherein the first and second swing cams are provided with identical swing motion characteristic through the first and second motion transmission mechanisms, and
• wherein the first swing cam has a cam profile configured to provide a valve lift curve of the engine valve for the first group of cylinders which is identical to a valve lift curve of the engine valve for the second group of cylinders,
• the cam profile of the first swing cam being set as an envelope which is drawn by arcuate loci of the cam follower following the first swing cam when the engine valve for the first group of cylinders is operated to be open and closed,
• the envelope being determined on the basis of a distance between a center of curvature of each of the loci of the cam follower and the axis of the first swing cam, and an angle which is formed between a line extending through the center of curvature of each of the loci of the cam follower and the axis of the first swing cam and a line extending through the axis of the first swing cam and a connection point between the first swing cam and the first motion transmission mechanism.

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 valve actuating member including a cam follower which follows 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 includes a first swing cam for the first group of cylinders and a second swing cam for the second group of cylinders, and the motion transmission mechanism includes a first motion transmission mechanism for the first group of cylinders and a second motion transmission mechanism for the second group of cylinders,
• wherein the first and second motion transmission mechanisms are constructed to provide the first and second swing cams with identical swing motion characteristic, and
• wherein the first swing cam has a cam profile which is different from a cam profile of the second swing cam, the cam profile of the first swing cam being set as an envelope which is drawn by arcuate loci of the cam follower of the valve actuating member which follows the first swing cam when the first swing cam is operated so as to provide a valve lift curve of the engine valve for the first group of cylinders which is identical to a valve lift curve of the engine valve for the second group of cylinders.