| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine which can exhibit a suitable NOx purification capacity irrespective of a temperature environment of NOx catalysts, in the exhaust emission control device which is constituted by arranging at least two selective reduction type NOx catalysts in series in an exhaust passage.SOLUTION: An exhaust emission control device comprises: a selective reduction type upstream-side NOx catalyst which is formed by containing a prescribed first metal component exhibiting an oxidation capacity; a selective reduction type downstream-side NOx catalyst which is arranged at a downstream side of the upstream-side NOx catalyst in an exhaust passage, and formed by containing a prescribed second metal component exhibiting an oxidation capacity; and a reductant supply part which supplies ammonia or a precursor of ammonia into exhaust gas flowing into the catalyst at an upstream side rather than the upstream-side NOx catalyst. Then, the oxidation capacity at the upstream-side NOx catalyst by the prescribed first metal component under the same temperature condition is set lower than the oxidation capacity at the downstream-side NOx catalyst by the prescribed second metal component. |
