Method and apparatus for controlling an engine

摘要

A control method of an engine including at least an HC adsorbing catalyst for adsorbing HC at a low temperature, and emitting adsorbed HC at a high temperature, and a three-way purifying function on the same carrier, and an NOx adsorbing catalyst having an NOx adsorbing function for adsorbing or occluding NOx in oxidizing atmosphere, and emitting NOx in reducing atmosphere, and a three-way purifying function. The engine operated with stoichiometric value or a rich air-fuel when a temperature of the HC adsorbing catalyst and/or a temperature of the NOx adsorbing catalyst is equal to/lower than a predetermined value. The engine is operated with a lean air-fuel ratio when a temperature of the HC adsorbing catalyst and/or a temperature of the NOx adsorbing catalyst is equal to/higher than the predetermined value.