| 摘要 |
PURPOSE:To prevent the occurrence of an eddy exhaust current and improve exhaust efficiency by so making a sub-chamber opening and closing valve in the exhaust port of a two-cycle engine as to keep the surface thereof even with the wall surface of the exhaust port when the valve is closed. CONSTITUTION:The exhaust port 4 of a two-cycle engine is provided with a sub-chamber 21 and an open/close valve of rotary type 27 is fitted to a port continuous to the exhaust port 4. When the engine is running at high speed, the valve 27 closes and when the engine is running at low speed, said valve 27 opens, thereby enabling the employment of an exhaust air pressure wave in an efficient way and improving scavenging efficiency. Said valve 27 is so made so to be flush with the surface of the exhaust port 4 when closed, thereby preventing the occurrence of an eddy exhaust current.
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