| 摘要 |
<P>PROBLEM TO BE SOLVED: To supply an exhaust emission control device of an internal combustion engine capable of improving an exhaust gas characteristic and fuel economy, by supplying a reducing agent in a proper quantity to a NOx catalyst, while reflecting consumption of the reducing agent corresponding to a deterioration degree of an upstream side catalyst. <P>SOLUTION: This exhaust emission control device has the catalyst 16 arranged in an exhaust system and having the oxidation function for purifying exhaust gas, the NOx catalyst 17 arranged on the downstream side of the catalyst of the exhaust system reducing and purifying captured NOx in a reducing atmosphere by capturing the NOx in the exhaust gas in an oxidation atmosphere, NOx reduction control means 6, 12, and 2 controlling the exhaust gas flowing in the NOx catalyst 17 in the reducing atmosphere by supplying the reducing agent to the upstream side of the catalyst for making the NOx catalyst 17 perform reduction operation of the NOx, a deterioration degree estimating means 2 estimating a deterioration degree DEGRA of the catalyst, and a correcting means 2 correcting a reduction control performing period in response to the estimated deterioration degree DEGRA of the catalyst. <P>COPYRIGHT: (C)2008,JPO&INPIT |
