| 摘要 |
<p>PURPOSE:To make it possible to set an optimum valve opening timing at all times by providing a retaining means for retaining an engine valve at a valve close position while storing valve opening force by a valve system can in a resilient member, between the engine valve and the valve system cam, and controlling retaining state release timing of the retaining means. CONSTITUTION:When a valve system cam shaft 14 is rotated by the operation of an engine, an intake valve 5 is opened and closed with a specified timing by the cooperation of an intake cam 15 and valve springs 11, 12. In this case, under a specified operation state of the engine, an intake valve 5 energizes an electromagnet 13 in a retaining means before the valve turns into a lift state, thereby to attract a spring retainer 9. Under a state that the valve 5 is lifted, a rocker arm 18 is turned while a twist spring 20 is twisted, and the valve 5 is retained at a valve close position. Valve opening force stored in the spring 20 is released by shutting energization to the magnet 13 off when the rotational angle of the cam shaft 14 reaches to the point which is located just before the amount of valve lift becomes the maximum to rapidly open the valve 5.</p> |
