| 摘要 |
<p>PROBLEM TO BE SOLVED: To control air-fuel ratio in exhaust gas to a target air-fuel ratio as well as control supply air-fuel ratio of an engine to a target supply air-fuel ratio in a system introducing secondary air in an exhaust system. SOLUTION: An exhaust pipe has an oxygen sensor or air-fuel ratio sensor. When a requirement for feedback control is satisfied, a secondary air introduction amount feedback correction factor SAIR is calculated based on detected air-fuel ratio in exhaust gas after secondary air is introduced. Then, feedback control of secondary air introduction amount is performed so as to make air-fuel mixture in exhaust gas target air-fuel ratio TGINAF. In addition, an actual supply air-fuel ratio SAIRAF of an engine is calculated based on the target air-fuel ratio TGINAF and variation in air-fuel ratio due to introduction of secondary air (hatched portion). Based on the deviation DELAF between a target supply air-fuel ratio TGAF and the supply air-fuel ratio SAIRAF, a learning correction factor KGij for fuel injection volume is renewed. Correction of fuel injection volume by means of the learning correction factor KGij makes it possible to control the supply air-fuel ratio SAIRAF to the target supply air-fuel ratio TGAF.</p> |
