EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of suitably converting NOx in exhaust gas even when a particulate filter is being forcibly regenerated.

SOLUTION: The particulate filter 40 and an ammonia selective reduction type NOx catalyst 42 are provided between an oxidation catalyst 36 and a HC selective reduction type NOx catalyst 44. A control means is provided for stopping supply of ammonia from the ammonia supply means 54 when the particulate filter 40 is being forcibly regenerated by supplying HC from a HC supply means 52 and increasing quantity of HC supplied from the HC supply means 52 from quantity necessary for forcible regeneration of the particulate filter 40 by predetermined quantity when it is judged that the HC selective reduction type NOx catalyst 44 is activated.

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