| 摘要 |
An internal combustion engine having a plurality of cylinders, at least one of the cylinders having cam-activated exhaust and intake ports and cam lobes shaped to provide selective maintenance of the exhaust port in either a continuously or periodically opened condition and the intake port in either a continuously or periodically closed condition. The cam lobes may be positioned upon a camshaft which is slidingly and rotatably disposed such that it is capable of shifting between first and second positions. The cam lobes may define first and second surfaces which activate the exhaust and intake ports as the camshaft moves from the first to the second position. The cam surfaces which maintain the exhaust and intake ports in the continuously opened and closed conditions respectively, may be cylindrical and concentric to the camshaft. |
