Patent ID: 6141960
Filing Date: 2000-11-07
Classification: B01D,F01N,F02B,F02D,F02M,Y02A,Y02T

Abstract:
An exhaust gas purifying system having a nitrogen oxide absorbing material disposed in an exhaust line of an internal combustion engine for absorbing nitrogen oxides in exhaust gases containing other emissions that are sulfuric components poisoning the nitrogen oxide absorbing material when a fuel mixture is leaner than a fuel mixture of an excess air factor of 1 (one) to reduce the nitrogen oxides thereby purifying the exhaust gas said exhaust gas purifying system comprising:engine operating condition detecting means for detecting a specific engine operating condition in which said nitrogen oxide absorbing material absorbs said other emissions; andcarbon monoxide supply means for supplying carbon monoxide to said nitrogen oxide absorbing material so that said nitrogen oxide absorbing material absorbs said carbon monoxide and desorbs said other emissions while said specific engine operating condition is detected:wherein said carbon monoxide supply means produces a rich fuel mixture with an air-fuel ratio represented by an excess air factor equivalent to 1 (one) or higher locally in a combustion chamber of the engine and a lean fuel mixture with an air-fuel ratio represented by an excess air factor lower than 1 (one) in the combustion chamber around said rich fuel mixture and bums said rich and lean fuel mixtures thereby providing an increase in an amount of carbon monoxide in the exhaust gas.