| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress degradation of exhaust emissions and degradation of fuel economy. <P>SOLUTION: In an exhaust emission control system of an internal combustion engine reducing a NOx catalyst by adding a reducing agent to an exhaust system 40 of the internal combustion engine, an oxidation catalyst 42 is provided downstream of the NOx catalyst 41, and A/F sensors 61, 62 are provided upstream and downstream of the oxidation catalyst 42 respectively. When a predetermined lean fuel air ratio is detected by the A/F sensor 61 and it is determined that the output difference between the two A/F sensors 61, 62 is large, the amount of fuel added per predetermined time period which is supplied by a reducing agent adding valve 16 is decreased. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
