| 摘要 |
PURPOSE:To save fuel consumption without deteriorating exhaust gas by a method wherein a closed loop control is effected in accordance with specified constitutents of the exhaust gas when the load of an engine is high while an open loop control shifting the air-fuel ratio to a lean side is effected when the load of the engine is low. CONSTITUTION:A control circuit 20 for fuel injection valves 5... calculates a standard fuel injection amount or a standard injection time width Tp from the revolving number N of an engine and a suction air volume Q based on each outputs of a revolution sensor 10 and a suction air volume sensor 8 at first upon operation. Subsequently, the value of Tp is compared with a decided value Tp , and if Tp>=Tp , it is decided that the engine is in the high load, and the closed loop control is effected. On the other hand, if Tp<Tp , it is decided that the engine is in the low load and the open loop control for the air-fuel ratio of the lean side is effected. An air-fuel ratio correcting amount in said respective control system is read out by a ROM 107. In this case, a coefficient of excess air lambda is controlled so as to be about one (1) upon the closed loop control while the same is controlled so as to be about 1.2 upon the open loop control. |
