To precisely decide deterioration of an NOx adsorber even in the case when a specified amount of the NOx adsorber and a large amount of an oxygen adsorber are arranged in an exhaust air passage.
This exhaust emission control device for an engine furnished with a reducing agent increasing means 38 to increase a reducer to be supplied to a NOx reducing catalyst 22 is constituted to carry out control to increase the reducer to be supplied to the NOx reducing catalyst 22 for a previously set first period of time and to restrain increase of the reducing agent for a previously set second period of time by the reducing agent increasing means 38 in the case where temperature of the NOx reducing catalyser 22 assumed by a catalyst temperature assuming means 37 is lower than standard temperature by having the catalyst temperature assuming means 37 to assume temperature of the NOx reducing catalyst 22.
KUROKAWA TAKAHIRO
ICHIKAWA TOMOJI
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