DEVICE FOR PURIFYING EXHAUST GASES FOR AN INTERNAL COMBUSTION ENGINE

摘要

A device for purification of exhaust gases of an internal combustion engine capable of achieving combustion of a fuel with lean air-fuel ratios. A NOx-adsorbing mechanism is installed in the exhaust line of the engine. That NOx-adsorbing mechanism can absorb the NOx present in the exhaust gases in the presence of excess oxygen and can release the absorbed NOx when the oxygen concentration of the exhaust gases decreases. The NOx-adsorbing mechanism does not contain any composition capable of acting as an NOx reduction catalyst, and especially no precious metal, and further a three-way catalyst is installed in the exhaust line downstream from the NOx-adsorbing mechanism.