| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control method of an exhaust emission control system and the exhaust emission control system capable of restraining the deterioration in an exhaust gas state while minimizing the deterioration in fuel economy by accurately estimating a deterioration degree of a catalyst without using a concentration sensor of an exhaust gas component such as a NOx concentration sensor. <P>SOLUTION: When an operation state of an internal combustion engine is a predetermined operation state, and when the temperature T1m of exhaust gas flowing in the catalyst falls within a second temperature range ΔT80 respectively narrower by 10% in a vertical width than a first temperature range ΔT100 between the activation starting temperature Ta before the deterioration in the catalyst and the activation finishing temperature Tb, the deterioration degree is determined, and the deterioration index temperature Tic is set as a moving distance to the high temperature side of a light-off characteristic of the catalyst, and this deterioration index temperature Tic is added to the reference determining temperature T0b before the deterioration, and is used as the determining temperature T0 for controlling an exhaust gas temperature rise. <P>COPYRIGHT: (C)2007,JPO&INPIT |
