| 摘要 |
PURPOSE:To certainly operate a rotary valve in cold time by manufacturing the rotary valve for opening and closing an auxiliary exhaust passage from the material having the larger thermal expansion coefficient, in a 2-cycle engine equipped with a main exhaust passage and an auxiliary exhaust passage. CONSTITUTION:An auxiliary exhaust passages 3 which are opened in high-speed operation are formed on the both sides of the main exhaust passage 2 of a 2-cycle engine, and a rotary exhaust valve 7 is installed into said passage 3. A governor 8 driven by the engine moves in reciprocation a rack rod 10 through a lever 13, and the exhaust valve 7 is turned by the rack. The valve shaft of the exhaust valve 7 revolves in a housing 8, and the material of the shaft 7 is made of the material having the larger thermal expansion coefficient of that of the housing 8. Since the temperature is high in engine revolution, the gap 9 is small, and the intrusion of carbon, or the like is prevented, and even if carbon intrudes a little, the gap windens when engine is at a low temperature, and the operation of the valve 7 at low temperature is not badly influenced. |
