System and method for controlling air-fuel ratio in internal combustion engine

摘要: A system for controlling fuel injection in an internal combustion engine such that when the target air-fuel ratio is switched from a rich value to lean value, ratios are by sequentially decreasing amount of injected into cylinders, example four cylinder #1, #2, #3 and #4 with predetermined time differences. During this time, electronic air control valve (EACV) controlled manner it stepwise opened switching thereby causing torque remain same prevent generation shock. When has been level level, amounts cylinders they increased differences, EACV closed. Thus, possible avoid shock, while preventing degradation emission during ratio.