| 摘要 |
PROBLEM TO BE SOLVED: To realize excellent purifying performance in an internal combustion engine of such a type that an exhaust gas is refluxed. SOLUTION: An exhaust gas path 12 of an engine 11 is provided with a catalyst 14 and an upstream part of the path 12 is provided with a reducer feed injector 15 for feeding a reducer. The exhaust gas path 12 is made to communicate with an intake path through an exhaust gas reflux path 21 having an exhaust gas reflux control valve 22. The exhaust gas path 12 is provided with an exhaust gas temperature sensor 19 for detecting an exhaust gas temperature and an oxygen concentration sensor 20 for detecting exhaust gas oxygen concentration. An ECU 16 judges whether the catalyst 14 is within an active temperature range or not, based on the exhaust gas temperature by the exhaust gas temperature sensor 19 and the oxygen concentration by the oxygen concentration sensor 20. When the catalyst 14 is within the active temperature range, the reducer feed injector 15 is operated to feed the reducer. |
