| 摘要 |
PURPOSE:To increase the output of a two-cycle engine, by raising the scavenging efficiency to a great extent by preventing blow-back and blow-by of fresh air through provision of a valve for opening and closing a scavenging passage. CONSTITUTION:A scavenging port 9 is so positioned that it is opened at the same timing as an exhaust port 11 or earlier than the exhaust port 11. At the initial stage of scavenging period, supply of fresh air into a combustion chamber is prevented by a valve 22 depressed by a cam 21 for controlling scavenging air even if the scavenging port 9 is opened. However, when combustion gas in the combustion chamber is exhausted and pressure in the combustion chamber is lowered, depression of the valve 22 by the cam 21 is removed at a proper timing, so that the valve 22 is opened by the force of a return spring 22 and fresh air is introduced into the combustion chamber. |
