Apparatus and method for emission control of an internal combustion engine

摘要

A catalytic emission control apparatus of an internal combustion engine (1) that has an engine stop mode of stopping the internal combustion engine (1) during a run of a vehicle utilizes an oxygen absorption-storage action of an emission control catalyst (18) disposed in an exhaust passage (7) of the internal combustion engine (1). The emission control apparatus has storage computing means (18) for computing a storage of oxygen in the emission control catalyst (19), and air-fuel ratio control means (18) for performing an air-fuel ratio control of the internal combustion engine (1) based on the storage of oxygen computed by the storage computing means (18). The storage computing means (18) computes the storage of oxygen during the engine stop mode of the internal combustion engine (1). The air-fuel ratio control means (18) performs the air-fuel ratio control when the internal combustion engine (1) is restarted after the engine stop mode is discontinued, based on the storage of oxygen computed by the storage computing means (18) during the engine stop mode.