Air-fuel ratio feedback control system having air-fuel ratio sensors upstream and downstream of three-way catalyst converter

摘要

In an air-fuel ratio feedback control system including air- fuel ratio sensors upstream and downstream of a three-way catalyst converter, the cold-condition compensating term is calculated in accordance with the upstream air-fuel ratio sensor disposed upstream of the catalyst converter, and the O.sub.2 storage term is calculated in accordance with the downstream air-fuel ratio sensor disposed downstream thereof.