| 摘要 |
A valve actuating cam has a periphery that can be varied in shape to control the opening and closing of one or more valves associated with a cylinder of an internal combustion engine. One portion of a valve assembly can be moved outwardly to change the valve lift. A band can surround the movable cam portion and cam body portion, and can form at least a major portion of the exterior surface of the cam that engages a cam follower such as a valve operating rocker arm. The timing of the opening and closing of one or more valves can be adjusted by adjusting the peripheral shape of the cam. The shape can be adjusted to start a ramp portion of the cam peripheral surface earlier to cause a valve to open earlier and to end a ramp portion later to cause the valve to close later with a first load on the engine and to open and close earlier when the engine is under a second load that is less than the first load. Wedges and wedging surfaces under the band and movable with the movable portion of the cam can be used to adjust the timing. |
