EXHAUST EMISSION CONTROL SYSTEM

摘要

PROBLEM TO BE SOLVED: To effectively improve catalyst temperature estimation accuracy during catalyst regeneration processing.SOLUTION: An exhaust emission control system includes: an NOx occlusion reduction type catalyst 32; an NOx purge control section 70 that executes catalyst regeneration processing for reducing NOx occluded in the NOx occlusion reduction type catalyst 32 for purification by making exhaust gas rich; first discharge amount storage sections 82A, B that acquire and store beforehand the amounts of HC and CO discharged from an internal combustion engine 10 during execution of the catalyst regeneration processing; a first heat generation amount estimation section 88B that estimates HC and CO heat generation amounts of the NOx occlusion reduction type catalyst 32 on the basis of the amounts of HC and CO read from the first discharge amount storage sections 82A, B during execution of the catalyst regeneration processing; and a first catalyst temperature estimation section 88D that estimates a catalyst temperature of the NOx occlusion reduction type catalyst 32 during execution of the catalyst regeneration processing on the basis of the HC and CO heat generation amounts estimated by the first heat generation amount estimation section 88B.SELECTED DRAWING: Figure 10