| 摘要 |
PURPOSE:To increase the tension of a valve spring so as to prevent a valve from surging, by moving a seat of the valve spring in the side of a cylinder head when an engine is driven at a high speed, in the case of a control device which switches an acting characteristic of the valve in accordance with a speed of the engine. CONSTITUTION:The open-close acting characteristic of a valve 41 is changed in accordance with the speed of an engine. Of the seats 45, 47 of a valve spring 48 urging the valve 41 in its closing direction, the seat 45 in the side of a cylinder head 42 is movably provided in the direction of an axial line of the valve, increasing setting force of the valve spring by applying the pressure of oil to the bottom of the seat 45 through a supply oil passage 49 when the engine is driven at a high speed. In this way, surging of the valve can be prevented without causing the necessity for increasing its inertia mass. |
