| 摘要 |
PURPOSE:To reliably perform fuel return operation by first supplying fuel good in carburetion and atomization and then supplying fuel having good ignitionability with a designated timing lag at the time of fuel return from deceleration fuel cut. CONSTITUTION:The first fuel injection valve 21 for injecting fuel having good ignitionability is disposed in the secondary passage 9 of an inlet pipe 10 as an intake passage in the vicinity of a combustion chamber 7, and the second fuel injection valve 22 for injecting fuel good in carburetion and atomization is disposed in a throttle chamber 3 positioned in front of a throttle valve on the upstream side of the first valve 21. The first and second fuel injection valves 21, 22 are controlled by CPU 30 in such a manner that in case of the fuel return timing from deceleration fuel cut, the feed return timing of the second fuel injection valve 20 is made later for a designated amount of time than the first fuel return timing. Thus thick air fuel mixture positioned in the upper portion of the combustion chamber and thin air-fuel mixture positioned in the lower portion thereof are formed into stratification to improve ignitionability.
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