| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow both a higher Nox reduction rate and suppression of a fuel consumption for Nox reduction in an exhaust emission control system for reducing NOx by controlling combustion condition of an internal combustion engine to make an air-fuel ratio of exhaust discharged from the internal combustion engine in a rich condition. <P>SOLUTION: The exhaust emission control system of the internal combustion engine with a storage-reduction type NOx catalyst in an exhaust passage removes NOx stored in the storage-reduction type NOx catalyst by making the air-fuel ratio of exhaust flowing to the storage-reduction type NOx catalyst in a rich condition and by stopping the rich condition at t2 after a lapse of a predetermined time Δt from t1 when the air-fuel ratio of exhaust flowing from the storage-reduction type NOx catalyst reaches an air-fuel ratio on a richer side than a theoretical air-fuel ratio. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
