| 摘要 |
The present invention provides in a first aspect, with reference to the Figure, a valve operating mechanism for operating an inlet and/or exhaust valve (32) of an internal combustion engine. The mechanism comprises oscillating cam means (24) mounted for rotation about a first fixed axis (25). Means (20, 21) for oscillating the oscillating cam means (24) is provided which oscillates the oscillating cam means (24) between first and second rotational positions. Rocker means (28) is mounted for rotation about a second axis (29) and the rocker means engages and drives a valve (32). Cam follower means (34) is connected to the rocker means (28) and also engages the oscillating cam means (24). Thus, the rocker means (28) is rocked by the oscillating cam means (24) to drive the valve (32), the cam follower means following the profile of the oscillating cam means (24) between first and second contact positions respectively at the first and second rotational positions of the oscillating cam means (24). The cam follower means (34) is moveable with respect to the rocker means (28) and control means is provided for adjusting the position of the cam folllower means (34) relative to the axis of rotation of the rocker means (28) whereby the location of the first and second contact positions on the oscillating cam means (24) can be varied. The present invention provides in a second aspect, again with reference to the Figure, an engine having a camshaft (21) driven to rotate in timed relationship to the crankshaft of the engine and a reciprocating push rod (20) driven by the camshaft (21) which is used to transmit motion to the cylinder head of the engine. The engine is provided with transmission means to transmit motion from the push rod (20) to an inlet or exhaust valve (32) of the engine whereby the valve (32) is driven to reciprocate. The transmission means comprises oscillating cam means (24) directly or indirectly driven by the push rod (20), cam follower means (34), which follows the profile of oscillating cam means (24) and which is in driving connection with the inlet or exhaust valve (32) and means to alter the position of the cam follower means (34) relative to the oscillating cam means (24) which allows the cam follower means (34) to be controlled to follow different surface sections of the oscillating cam means (24) such that valve motion can be varied. |
