| 摘要 |
PROBLEM TO BE SOLVED: To adjust a valve lift amount in a directly striking type valve system of an engine. SOLUTION: Rotations of a cam 17 opens/closes an intake valve 5 through a hydraulic tappet 31. When the intake valve 5 is closed, lubricating oil is fed from a low pressure passage 29 to a low pressure chamber 38 of the hydraulic tappet 31 and the lubricating oil is fed to a high pressure chamber 39 through a check valve 40 to advance an outer plunger 36 to adjust a valve clearance. When the intake valve is opened, the lubricating oil is fed from a high pressure passage 32 to the high pressure chamber 39 to advance the outer plunger 36 to increase the valve lift amount. Since a control valve opens/closes the high pressure passage 32 depending on the revolution speed of the engine to reduce the valve lift amount in a low revolution speed area and increase the valve lift amount in a high revolution speed area, engine output is increased in all of speed areas including the low and high revolution speed areas.
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