| 摘要 |
PURPOSE:To surely prevent unburned substances from being produced due to incomplete combustion at the time of sharp deceleration, by detecting the intense negative pressure downstream to a throttle valve at the time of sharp deceleration so that a solenoid valve provided halfway in the slow fuel passage of a carburetor is put in operation for a prescribed time. CONSTITUTION:At the time of sharp decelration, the degree of opening of a throttle valve 5 is lower than the idling level and the rotational frequency of an engine is very high. For that reason, the negative pressure of intake downstream to the throttle valve 5 is transmitted to the negative pressure introduction chamber 26 of a pressure switch 18 through the port 31 of a three-way electromagnetic changeover valve 19 and to another introduction chamber 25 through a negative pressure delay valve 20. The speed of the transmission of the negative pressure to the chamber 25 is made lower than that of the negative pressure to the chamber 26 to make a pressure difference between the chambers 25, 26. A spring 29 is compressed by the pressure difference to open the pressure switch 18 to close a solenoid valve 13 so that the halfway part of a slow fuel passage 6 is shut off. As a result, fuel supply to an idling port is stopped to avoid feeding an excessively high concentration of fuel. |
