| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent added reducing agent from being introduced to an exhaust gas take out port of an exhaust gas recirculation device under a wide range of operation conditions in an exhaust emission control device for an engine having a reducing agent adding means arranged in an exhaust branch pipe. <P>SOLUTION: When the reducing agent adding means adding reducing agent is arranged in the exhaust branch pipe, addition of the reducing agent is prohibited during an exhaust stroke of a cylinder to which the reducing agent flows reversely when the reducing agent is added. When it is determined that a period of supplying the reducing agent from the reducing agent adding means is long as compared with a period of an exhaust stroke of a cylinder of a plurality of cylinders, addition of the reducing agent is interrupted during a exhaust stroke of a cylinder in a position where the reducing agent added by the reducing agent adding means is introduced to the take out port of the exhaust gas recirculation device with exhaust gas. After that, addition of reducing agent is resumed in conformity with an exhaust stroke of other cylinders. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
