| 摘要 |
PROBLEM TO BE SOLVED: To burn a fine particle accumulated at a particulate filter in a short time. SOLUTION: The particulate filter 22 is arranged in an engine emission passage. When the fine particulate accumulated on the particulate filter 22 is predicted or judged to change in property into the property to be hard to oxide, compared with just after the accumulation, the air to fuel ratio of the exhaust gas flown into the particulate filter 22 is temporarily changed from lean to rich. |
