| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine which can remove sulfur while suppressing deterioration in fuel consumption. SOLUTION: If an air/fuel ratio in the outlet of a NOx trap catalyst is not shifted to a rich side (S10), a post injection amount in the next cycle is increased (S12). If a period when the outlet air/fuel ratio is rich air/fuel ratio is shorter than a target rich keeping time (S14), a post injection amount is increased in the next cycle (S18) and torque correction is carried out (S16). A period that the outlet air/fuel ratio is rich air/fuel ratio is longer than a target rich keeping time (S20), the post injection amount is reduced in the next cycle (S22). When S-purge treatment is continued a plurality of times, a sulfur portion occluded in the NOx trap catalyst is regarded as being reduced (S24), the target rich air/fuel ratio AF<SB POS="POST">rich</SB>is shifted to a lean side (S26) and this routine is terminated. COPYRIGHT: (C)2013,JPO&INPIT |
