EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device reducing NOx by controlling a ratio of NO to NO2.

SOLUTION: The exhaust emission control device comprises a selective reduction type catalyst 16 equipped in the middle of an exhaust pipe 11 of an engine 1 and can selectively react NOx with ammonia even under oxygen coexistence; a urea water adding means 22 to add urea water 21 as a reduction agent in exhaust gas 9 on the inlet side of the selective reduction type catalyst 16; a plasma generating device 25 to generate NO2by discharge in the exhaust gas 9 on the upstream side more than addition of the urea water adding means 22; and a control device 28 to make a urea water 21 adding means add the urea water 21 by controlling the plasma generating device 25 such that a ratio of NO to NO2in the exhaust gas 9 is adjusted.

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