Patent ID: 6536210
Filing Date: 2003-03-25
Classification: B01D,B01J,F01N,Y02T,Y10S

Abstract:
An exhaust gas purification apparatus for an internal combustion engine capable of lean operation, comprising:a non-zeolite Ir-containing selectively reducing catalyst in which Iridium is an active species thereof and NOx is selectively reduced in a lean atmosphere by HC as a reducer is disposed in an exhaust system of said internal combustion engine, said Ir-containing selectively reducing catalyst being disposed on an upstream side of the exhaust system; and an NOx adsorptive catalyst which adsorbs NOx in the lean atmosphere and reduces the adsorbed NOx at a theoretical air-fuel ratio, said NOx adsorptive catalyst being disposed on a downstream side of the exhaust system; wherein said Ir-containing selectively reducing catalyst is coated with a top layer of perovskite-type complex oxide to prevent dispersion or vaporization of the Iridium.