| 摘要 |
A valve operating mechanism for operating a plurality of valves of an internal combustion engine includes a camshaft rotatable in synchronism with rotation of the internal combustion engine and having an array of three cams including a high-speed cam positioned at one end of the array. Three cam followers are held in sliding contact with the cams, respectively, for operating the valves according to cam profiles of the cams. The cam followers are selectively interconnected and disconnected to operate the valves at different valve timings in different speed ranges of the internal combustion engine. The speed ranges include a high-speed range in which all of the valves are controlled by the cam profile of the high-speed cam. The three cams may include low- and medium-speed cams, or two identical or different low-speed cams, in addition to the high-speed cam. These cams may be differently arranged in the array, and the cam followers include those which slidably engage one or two of the cams for operating the valves. The valves are operated selectively in low- and high-speed ranges, or in low-, medium-, and high-speed ranges, with different combinations of the cams. |
