| 摘要 |
PURPOSE:To improve the output characteristic with in the wide range of an engine by shifting the operation revolution speed range for an opening and closing valve for sub exhaust hole of a 2-cycle engine and an opening and closing valve for resonator chamber for exhaust pulsation. CONSTITUTION:A resonator chamber 18 is arranged contiguously in the vicinity of the port of the exhaust hole 6 of a 2-cycle engine, and an opening and closing valve 19 is installed into the connection part. A sub exhaust hole 15 is formed onto the both sides of the exhaust hole 6, and each opening and closing valve 16 is installed into the passages. The opening and closing valve 19 is closed at the first set revolution speed for the lower engine revolution speed, and the opening and closing valve 16 is opened at the second set revolution speed higher than the first set revolution speed. Since the opening and closing valve 16 is closed when the revolution speed is below the first set revolution speed, exhaust flows only from the opening 6, and blowing-bye is prevented, and the opening and closing valve 19 is opened to correspond to the exhaust pulsation at low speed. Over the first set revolution speed, the opening and closing valve 19 is closed, and over the second set revolution speed, the opening and closing valve 16 is opened to increase the exhaust at high speed. |
