Emission control apparatus of internal combustion engine and control method for the emission control apparatus

摘要

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