| 摘要 |
<p>A combustion engine has a valve opening and closing arrangement in which the valve is driven positively by a cam in both the opening and closing driections. The cam (1) may be tubular in form with the valve engaging on both the inner and on the outer periphery of the cam to provide positive driving in both directions. The contact between the valve and the tubular cam (1) can be through free-running ball bearings (2).</p> |
