Exhaust gas purification device of internal combustion engine and method therefore

摘要

Injection of secondary air (AI) into an exhaust gas pipe upstream of an exhaust gas purification catalyst is performed after a startup of an engine, in order to accelerate the warm-up of the catalyst. If the degree of catalyst warm-up during the AI is greater than or equal to a predetermined criterion degree of the warm-up and the engine output is greater than or equal to a criterion output, the injection of secondary air is stopped and exhaust gas purification on the catalyst is conducted so as to curb degradation of emissions.