| 摘要 |
PURPOSE:To maintain a predetermined accelerating property while enabling an internal-combustion engine to be run with lean air-fuel ratio, by maintaining the air-fuel ratio in all cylinders at at least a first predetermined value when the engine load is smaller than a set value and maintaining same in some cylinders at a second predetermined value when the engine load is larger than the set value. CONSTITUTION:In an electronic control unit 40 receiving signals of respective sensors 28, 29, 30 of intake tempetature, throttle position, water temperature and an air flow meter 2, etc. to control a fuel injection valve 41, etc., a central processing unit 56, ROM 57, input/output interface 61, etc. are connected to each other through a bus 62. When an engine load is less than 3/4, air fuel ratio in all cylinders is maintained at 20-25, and when same exceeds 3/4, the air-fuel ratio in some cylinders maintained at 12-15, that in the other cylinders being varied according to the air-fuel ratio charcteristics stored in ROM 57. Thus, the mixture becomes sufficiently lean so that noxious components in exhaust gas are reduced to ensure sufficiently a desired accelerating property. |
