| 摘要 |
The present invention is provided with: a NOx occlusion/reduction catalyst 32; a catalyst-temperature estimation unit 115; a NOx-occlusion-amount estimation unit 113; a regeneration control unit 100 which implements catalyst regeneration for recovering NOx occlusion capacity of the NOx occlusion/reduction catalyst 32 when the exhaust is in a rich state; an interval setting unit 118 for setting the target interval from the end of the catalyst regeneration to the start of the next catalyst regeneration; a catalyst-regeneration-start processing unit 110 which, when the NOx occlusion amount becomes at least a threshold value, and the elapsed time since the end of the catalyst regeneration has reached the target interval, starts the next catalyst regeneration; and an interval-target-value correction unit 119 which, in cases when the catalyst temperature is less than a prescribed catalyst activation temperature, extends and corrects the target interval on the basis of the NOx occlusion amount. |
