| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent melt down of a filter by inhibiting variation of fuel injection quantity during regeneration of the filter, in an exhaust emission control device for an engine provided with the filter carrying oxidation catalyst. <P>SOLUTION: When accumulation quantity of particulate matter gets to a predetermined value or more, unburned fuel is supplied to the oxidation catalyst by performing auxiliary injection additionally injecting fuel in expansion stroke or exhaust stroke for filter regeneration, temperature of exhaust gas passing through the filter is raised by oxidation reaction heat thereof, and particulate matter collected on the filter is burned. Then, in the auxiliary injection for the filter regeneration, injection quantity is controlled by open control according to an operation condition when gas temperature in a downstream of the filter is lower than predetermined temperature, and injection quantity is controlled by feed back control to make oxygen concentration in a downstream of the filter to target oxygen concentration when the temperature reaches the predetermined temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT |
