| 摘要 |
PURPOSE:To improve the efficiency of filling due to the pulsation of exhaust with a simple structure by providing independently respective flaring exhaust pipes of a 2 cycle engine having a pair of cylinders having explosions at 180 deg. intervals and communicating to each other at the ends through a valve opened and closed according to the rotational frequency of an engine. CONSTITUTION:Adjacent cylinders 1, 2 of a 2 cycle engine are set to have explosions at 180 deg. intervals. Flaring exhaust pipes 41, 42 are respectively connected to exhaust ports 31, 32 and communicate to each other at pipe walls 5 at the ends. A switch valve 6 is provided at the connection and an end 7a of a tail pipe 7 is disposed to project from an opening of the switch valve 6. In high speed of the engine, the valve 6 is closed and the exhaust pipe length is shortened and diverged so that exhaust pulsation adapted to the high speed is formed. In the low speed rotation of the engine, the valve 6 is opened so that the exhaust pulsation of one cylinder is introduced to the exhaust port of the other cylinder, the exhaust pipe length is elongated and the pipe end is narrowed to form the exhaust pulsation adapted to the low speed. |
