| 摘要 |
PURPOSE:To improve sealing ability of a valve by providing side chamber of an exhaust passage on an exhaust port, whereby in case of opening and closing between the port and the chamber by a rotary valve, at the time of valve closing, the whole valve is pressed to the exhaust passage side by valve closing force produced by bringing the valve end portion into contact with a stopper. CONSTITUTION:A chamber 5 is provided on the side of an exhaust port 4, and connection and disconnection between the chamber and the exhaust port is conducted by a rotary valve 22. In case of low speed, the rotary valve 22 is turned clockwise by a rod 25 and an arm 12 to connect the chamber 5 to the exhaust port 4, so that pulsation wave for preventing blow-by of exhaust gas is formed. In case of high speed, the rotary valve 22 is turned counter-clockwise by the turning movement of the arm 12, so that a projection 27 mounted on the end portion of the valve is brought into contact with a stopper 26. At that time, the closing turning force of the arm 12 produces force for pressing the whole rotary valve 22 to the exhaust port 4 side centering around a contact point of the stopper 26 and the projection 27, so that strong closing force is produced between a flat plate 10 of the rotary valve 22 and the side wall 6 of the port to accomplish sealing.
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