| 摘要 |
In order to prevent a decrease in the NOx purification rate when an addition is carried out to prevent the clogging of a reducing agent addition valve, a fuel addition valve, a catalyst having oxidizing ability, and a selective reduction NOx catalyst are provided in this order in the exhaust passage of an internal combustion engine, and when a prescribed condition for injecting fuel from a fuel addition valve is satisfied, the amount of fuel injected from the fuel addition valve is made less when the temperature of the selective reduction NOx catalyst is within a prescribed temperature range than when the temperature is outside of the prescribed temperature range. |
