| 摘要 |
PURPOSE:To devise improvement of the thermal efficiency of an engine and quality of the exhaust gas by providing a sub-scavenging passage to connect a sub-scavenging port and the inside of a suction pipe in the downstream of a non- return valve, and forming a partition for dense and thin fuel-air mixture in the suction passage. CONSTITUTION:The suction of an engine is carried out by a reed valve 8 and a piston 18 which opens and closes a suction port 16. A partition to separate dense and thin fuel-air mixture is provided in a suction passage 9. When main scavenging ports 15 are opened in a scavenging stroke, the fuel-air mixture in a crankcase 17 flows into a cylinder 5 through the main scavenging ports 15. When a pair of subscavenging ports 12 are opened dence fuel-air mixture in the suction passage 9 flows into a sub-scavening passage 11 through an opening 10 and is supplied inside the cylinder 5 through the sub-scavenging ports 12. In this way, the blow-bye loss of fresh air is reduced and the thermal efficiency of the engine and the quality of the exhaust gas are improved. |
