| 摘要 |
PROBLEM TO BE SOLVED: To eliminate poisoning by sulfate of a NOX storage reducing catalyst without performing operation control in diesel engine side, in the case of controlling exhaust emission of a diesel engine by the NOX storage reducing catalyst. SOLUTION: Relating to this operating method of an exhaust emission control device constituted by equipping a NOX storage reducing catalyst 11 in the halfway of an exhaust pipe 9 circulating exhaust gas 7 from a diesel engine 1 to suitably add a reducing agent 10 relating to this NOX storage reducing catalyst 11 and suitably make it detour around the NOX storage reducing catalyst 11 so as to make exhaust gas capable of flowing, periodically the reducing agent 10 is added while allowing the exhaust gas 7 to flow in the NOX storage reducing catalyst 11, to make its temperature rise to a prescribed temperature or more, additionally just thereafter the reducing agent 10 is made to detour around the NOX storage reducing catalyst 11 and again added thereto while allowing the exhaust gas to flow, de-vulcanization treating is applied.
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