| 摘要 |
PROBLEM TO BE SOLVED: To keep a valve closing state in a minimum cam lifting rate, effectively improve fuel consumption performance, and downsize a device. SOLUTION: When a cam shaft 13 is synchronously rotated with a crank shaft, an oscillation cam 20 is oscillated through an eccentric cam 15, a link arm 25, a rocker arm 18, and link member 26, for opening and closing an intake valve 12. When a control shaft 16 is rotated, the rotational position of the oscillation cam 20 is relatively shifted through the rocker arm 18, for varying a cam lifting characteristic. A specified valve clearance is set between the oscillation cam 20 and the intake valve 12 in a base circle periodθ1. The maximum cam lifting amount of the oscillation cam 20 is set larger than zero and smaller than the valve clearance in the minimum state of a cam lifting amount of the oscillation cam 20.
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