| 摘要 |
PURPOSE:To reduce the amount of discharge of a harmful gas component by a method wherein when the operation of the engine shifts from a condition in which a feedback control of the air-fuel ratio is to be performed to a condition in which a lean control of the air-fuel ratio is to be performed, the feedback control is performed for a predetermined period of time from the time of the above mentioned shifting. CONSTITUTION:The air-fuel ratio of a gas mixture sucked into the engine is controlled by a control circuit on the bases of values detected by various kinds of sensers. The control circuit operates such that: at Step 100, it judges whether or not a throttle switch is ON so that a throttle is closed to the full and if ON, a flag FLL is made 1 at Step 101; at Step 101, it judges whether or not the number of revolutions of the engine N is higher than a predetermined value NR and if higher, a fuel cut is performed at Step 108 while if otherwise, the feedback control at Steps 103-106 is performed; then, when the previous flag F11' is 1 at Step 114 so that the throttle is closed fully in a feedback control zone, a timer is started at Step 115; and when the counting of the timer is lower than a predetermined value TR, the feedback control at Step 103 and onward is performed while when the counting of the timer is higher than the predetermined value TR, the lean control of the air-fuel ratio at Step 117-119 is performed. |
