| 摘要 |
<p>An SAS two-cycle engine (10) has a cylinder block (12) that has a bore (14) with at least one scavenging port (32) and at least one fresh air port (62, 64) therein. The bore (14) extends to a crankcase (20). A piston (50) of the engine (10) is located within the bore (14) and separates a combustion chamber (52) of the bore (14) from the crank area (22) and is movable between a first position, in closest proximity to the crank area (22), and a second position. The air port (62, 64) and the piston (50) are configured such that air may flow from the air port (62, 64) into the combustion chamber (52) of the cylinder when the piston (50) is at the first position. In one example, the scavenging port (32) and the air port (62, 64) have edges that are selectively revealed upon movement of the piston (50). The air port (62, 64) includes an upper edge (66, 68), which may be contoured such that only a portion of the upper edge (66, 68) is exposed when the piston (50) is at the first position.
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