| 摘要 |
<p>The present invention pertains to an exhaust purification device for an internal combustion engine (10) which is equipped with a catalyst (45) on an exhaust passage (40). In the present invention, when the catalyst temperature is greater than or equal to a predetermined solid solution temperature, and the internal atmosphere of the catalyst is an oxidizing atmosphere, active elements form a solid solution in a carrier; and when the catalyst temperature is greater than or equal to a predetermined deposition temperature, and the internal atmosphere of the catalyst is a reducing atmosphere, active elements are precipitated from the carrier. In the present invention, when the solid solubility of active elements is less than a target solid solubility or the lower limit of a target solid solubility range, and the catalyst temperature is greater than or equal to the predetermined solid solution temperature, the air-fuel ratio of exhaust gas that flows into the catalyst is controlled so as to be leaner than a theoretical air-fuel ratio; and when the solid solubility of active elements is greater than the target solid solubility or the upper limit of the target solid solubility range, and the catalyst temperature is greater than or equal to the predetermined deposition temperature, the air-fuel ratio of exhaust gas that flows into the catalyst is controlled so as to be richer than the theoretical air-fuel ratio.</p> |
