| 摘要 |
PURPOSE:To enable to prevent the increase in noise at the time of acceleration by jointly providing a check valve and an orifice between a diaphragm of a secondary-side throttle valve servo mechanism and a venturi negative-pressure port for the carbureter. CONSTITUTION:When the negative-pressure at the venturi negative-pressure port 10 is increased at the time of rapid opening of a primary-side throttle valve 5, this change is transmitted to a diaphragm chamber 9 of the servo mechanism 8 to open the secondary-side throttle valve 7. But since a delaying mechanism 15 having the check valve 13 and the orifice 14 jointly is provided in a passage 11, the secondary-side throttle valve 7 is opened with a delay. Accordingly, the acceleration of the engine is delayed by a corresponding amount and proceeds slowly, so that the increase of noise can be securely prevented without bringing about the so-called blow-up, i.e. an abrupt increase in engine revolution frequency, even at the time of acceleration with little load, such as on a flat road. |
