| 摘要 |
PURPOSE:To prevent the slight push-up of a valve due to slight vibrations or backlash of a cam shaft by forming the cam profile of a valve moving mechanism in a linear gradient from the ramp end toward the start in a base circle segment. CONSTITUTION:The profile of a cam 1 is formed in a linear gradient from the ramp end Q3 toward the ramp start at a cam nose section 5 and a base circle 6 segment on the opposite side so that the hn value is decreased in sequence from the base circle center 7: h1, h2, h3. A clearance is generated between a hydraulic tappet and the cam, a valve is prevented from being slightly pushed up by slight vibrations or backlash of a cam shaft due to this clearance, thus the air-fuel mixture in a cylinder can be prevented from being leaked during a compression stroke. |
