Patent ID: 10052587

Abstract:
An exhaust purification system is provided with a NOx-occlusion-reduction-type catalyst and a NOx purge rich control unit that executes NOx purge in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than a catalyst temperature threshold value and a NOx occlusion amount of the NOx-occlusion-reduction-type catalyst is equal to or higher than an NOx occlusion amount threshold value and executes the NOx purge even when the catalyst temperature is lower than a catalyst temperature threshold value in a case where the NOx occlusion amount is equal to or greater than the occlusion amount threshold value, a fuel injection amount resulting from an accelerator operation is equal to or greater than an injection amount threshold value, and an exhaust temperature detected by a first exhaust temperature sensor is equal to or higher than an exhaust temperature threshold value.