Patent ID: 6588205
Filing Date: 2003-07-08
Classification: B01D,F01N,F02B,F02D,F02M,Y02A,Y02T

Abstract:
An exhaust gas purifying apparatus comprising:a three way catalyst provided in an exhaust pipe of an internal combustion engine; a NOx adsorption/reduction catalyst provided in the exhaust pipe to be located downstream of said three way catalyst, said NOx absorption/reduction catalyst absorbing NOx and SOx in exhaust gas in an oxidizing atmosphere and reducing NOx and SOx in exhaust gas in a reducing atmosphere; and SOx refresh operation means for raising a temperature of the NOx absorption/reduction catalyst and controlling an atmosphere in the exhaust pipe to a reducing atmosphere so that absorbed SOx is released from said NOx absorption/reduction catalyst, wherein at least one of Ni and an oxide of Ni is added to said NOx absorption/reduction catalyst to accelerate the reduction process of absorbed SOx performed in the NOx absorption/reduction catalyst, and wherein the Ni or oxide of Ni of said NOx absorption/reduction catalyst reacts with H2S in the exhaust gas to form NiS.