Patent ID: 6276132
Filing Date: 2001-08-21
Classification: B01D,B01J

Abstract:
An exhaust gas purifying system comprising:an exhaust gas composition regulating device for producing a low HC concentration reducing agent in a lean exhaust gas atmosphere where air-fuel ratio is leaner than a stoichiometric value, said exhaust gas composition regulating device being disposed in an exhaust gas passageway of a combustion device, said low HC concentration reducing agent being low in concentration of hydrocarbons to have an exhaust gas composition having a volume ratio of NOx/HC not less than 50 in the exhaust gas passageway downstream of said exhaust gas composition regulating device; anda NOx treating catalyst for reducing NOx in the presence of the low HC concentration reducing agent supplied from said exhaust gas composition regulating device, said NOx treating catalyst being disposed in the exhaust gas passageway and located downstream of said exhaust gas composition regulating device, the exhaust gas composition of said low HC concentration reducing agent being obtained in the exhaust gas passageway immediately upstream of said NOx reducing catalyst.