| 摘要 |
PURPOSE:To improve fuel consumption and to reduce the occurrence of a shock, by a method wherein a fuel cut valve and an air-fuel ratio control valve are closed during deceleration, and the opening timings of the two valves are staggered from each other. CONSTITUTION:An air-fuel ratio control valve 26, controlled according to a signal from an air-fuel ratio sensor 43, is situated in an auxiliary fuel passage 25 running from a vaporizer 23 to the downstream of a throttle valve 18 of an intake air passage 14. A fuel cut valve 29 is situated in a main fuel passage 24 running from the vaporizer 23 to a venturi part 17. The fuel cut valve 29 and the air-fuel ratio control valve 26 are simultaneously closed by means of a control device 40 during deceleration, and the air-fuel ratio control valve 26 is held in a closed state until the number of revolutions of an engine is decreased to a value lower than that of the fuel cut valve 29. This constitution prevents the useless feed of fuel during deceleration, and enables reduction of the occurrence of a shock during transfer to an idling region.
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