Patent ID: 6920752
Filing Date: 2005-07-26
Classification: F01N,F02D,Y02T

Abstract:
1. An exhaust emission control device of an internal-combustion engine comprising a three-way catalytic converter provided in an exhaust passage of the internal-combustion engine, and an air-fuel ratio varying element for forcedly varying an air-fuel ratio of exhaust flowing into said three-way catalytic converter, between a rich air-fuel ratio and a lean air-fuel ratio, wherein said exhaust emission control device further comprises a variation characteristic altering element for altering a characteristic of the variation of the air-fuel ratio effected by said air-fuel ratio varying element, said three-way catalytic converter has a HC selective oxidizing component for selectively oxidizing HC rather than CO, and a CO storage component for storing CO in a reducing atmosphere, and said variation characteristic altering element alters a characteristic of said variation depending on an stored CO quantity correlative value which correlates with a quantity of CO stored by said CO storage component of said three-way catalytic converter.