| 摘要 |
PURPOSE:To enable compulsory ventilation to be carried out by reducing the pressure pulsation of blow-by gas which is transmitted to the upstream side of a throttle valve, in the light-loading and low-revolution range, e.g., in idling. CONSTITUTION:A flow control mechanism 22 is arranged midway in a blow-by gas passage 20. Said flow control mechanism 22 has a small bypasses hole 24 formed on a partitioning wall 23 and is equipped with a blow-by gas flow passage closing valve 25 arranged in parallel to said small hole and a differential- pressure taking-out pipe 26 for driving said closing valve 25. In the idling state, the negative pressure generated at a differential-pressure taking-out port 26a is intensified, and said negative pressure is transmitted to a diaphragm chamber 27, and a valve body 30 is closely attached onto the valve seat surface. Therefore, only the small bypass hole 24 is kept in the opened state, and the pressure pulsation generated in a crankcase 8 is damped through said small bypass hole 24 and hardly transmitted to the opening part 20a on the upstream side of a throttle valve. |
