| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress increase of back pressure in exhaust passages to the utmost at the time of occlusion and reduction of NOx occluded in NOx catalysts and to improve mountability to a vehicle, in an internal combustion engine having the plurality of NOx catalysts arranged in parallel on the exhaust passages. <P>SOLUTION: This exhaust emission control system for the internal combustion engine has the two exhaust passages 3L, 3R connected with each of two divided cylinder groups 2L, 2R sharing exhaust gas. The three NOx catalysts 14, 15, 16 are provided in parallel on the exhaust passages 3L, 3R. Each of the two exhaust passages 3L, 3R is branched and connected with the three NOx catalysts 14, 15, 16, such that exhaust gas can be branched and flowed into the two exhaust passages 3L, 3R. When NOx occlusion amount of one of the NOx catalysts 14, 15, 16 is below predetermined NOx occlusion amount, exhaust gas is flowed into the three occlusion/reduction type NOx catalysts 14, 15, 16 from the two exhaust passages 3L, 3R. When NOx occlusion amount of the one of the NOx catalysts 14, 15, 16 exceeds the predetermined NOx occlusion amount, fuel is supplied while an exhaust gas flow rate flowed into the one NOx catalyst is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
