| 摘要 |
PURPOSE:To extend the effective stroke of an internal combustion engine without reducing scavenging efficiency by forming a scavenging port on the cylinder liner of the engine and disposing, on the scavenging port, a control valve for preventing flow-out of the gas in the cylinder. CONSTITUTION:Even if the top of a piston 10 descends kept across the upper end of a scavenging port 8 in the expansion stroke, a check valve 9 is closed since the inside of a cylinder 6 is at high pressure by means burned gas. At this time, the burned gas at high pressure in the cylinder 6 is checked by means of a check valve 9 at the positions where it enters into the scavenging port 8 and a check valve chamber 7. Thus, no burned gas flows into a scavenging chamber 11. Further, as the piston 10 descends to reach the vicinity of a bottom dead center, an exhaust valve 2 is opened and the burned gas in the cylinder chamber 6 is exhausted to an exhaust pipe 12 through an exhaust passage 16. Accordingly, since the pressure in the cylinder chamber 6 is lower than the pressure in the scavenging chamber 11, the check valve 9 is opened and new air in the scavenging chamber 11 flows into the cylinder chamber 6.
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