| 摘要 |
<p>A valve operating mechanism for an internal combustion engine is disclosed which includes a camshaft arranged in the cylinder head of an internal-combustion engine. A center shift cam is provided which can be selectively connected in a form-locking manner to be rotated on the camshaft or to be rotatable with respect to the cam shaft. On each side of the shift cam, one fixed cam is provided each of which is non-rotatably connected with the camshaft. In the full-load operation of the internal-combustion engine, an electronic control guides by way of a lock valve pressure oil into a hydraulic chamber of the fixed cam and in this case displaces pistons as well as a hollow piston to thereby connect the shift cam with one of the fixed cams. The form-lockingly coupled shift cam actuates intake valves by a relatively large lift by way of a tappet. In the partial-load operation, while the oil pressure is disconnected, the fixed cams actuate the tappet by a smaller lift.</p> |
