EXHAUST GAS CLEANING METHOD

摘要

Installed in the exhaust passageway of an internal combustion engine is a particulate filter (22) carrying an active oxygen release agent which takes in and retains oxygen when excess surrounding oxygen is present and which releases the retained oxygen, in the form of active oxygen when the surrounding oxygen concentration lowers. The air-fuel ratio of exhaust gases flowing into the particulate filter (22) is normally maintained on the lean side and is sometimes temporally switched to the rich side. When the air-fuel ratio of the exhaust gases is switched to the rich side, the active oxygen released from the active oxygen release agent accelerates the oxidative reaction of particulates on the particulate filter, thereby continuously oxidatively removing the particulates contained in the exhaust gases without generating luminous flames on the particulate filter (22).