EXHAUST CLEANER FOR INTERNAL COMBUSTION ENGINE AND METHOD OF EXHAUST PURIFICATION

摘要

A technique for exhaust purification by which nitrogen oxides contained in an exhaust gas discharged from an internal combustion engine in which a fuel burns mainly under lean conditions can be removed at a high efficiency even after low-temperature initiation. An exhaust cleaner (9) is provided in which the atmosphere of an exhaust gas discharged from an internal combustion engine (1) is periodically changed between oxidizing/reducing atmospheres to thereby remove nitrogen oxides from the gas. The cleaner comprises: a modifier (18) which introduces a modifying gas comprising hydrogen and carbon monoxide into a discharge channel (11) which leads the exhaust gas to the atmospheric-air side; an adsorption means (30) which includes at least silver oxide which consumes the hydrogen and is reduced, the adsorption means (30) adsorbing the nitrogen oxides and releasing the adsorbed nitrogen oxides with increasing temperature; and a purification means (17) which consumes the carbon monoxide and reduces the nitrogen oxides to purify the exhaust gas.