| 摘要 |
PURPOSE:To facilitate starting of an engine, by operating a solenoid valve provided in a slow-speed fuel system of a carburetor with lean mixture of a prescribed air-fuel ratio for a prescribed period from a prescribed time at the time of warming up and restarting an engine. CONSTITUTION:A solenoid valve is provided in a slow-speed fuel passage of a carburetor. Normally, the solenoid valve is feedback controlled by means of an O2-sensor. At the time of starting an engine, over-rich mixture having a prescribed air-fuel ratio is supplied. However, since it is too rich for use at the time of restarting the engine, the solenoid valve is set to a duty ratio (DL) for prescribed lean air-fuel ratio for a period (T) from the initial starter driving time (T1) to the initial time (T2) of complete explosion in case that the temperature of engine water is high and the engine speed is higher than 25rpm (N1) but lower than 400rpm (N2) at which complete explosion is caused. In other cases, the solenoid valve is set to an ordinary duty ratio (DI) for over-rich mixture or to an ordinary feedback duty ratio (DW). |
