| 摘要 |
PROBLEM TO BE SOLVED: To effectively improve catalyst temperature estimation accuracy when catalyst heat insulation control is performed during an idle operation.SOLUTION: An exhaust emission control system includes: an exhaust aftertreatment device 30 having catalysts 31, 32 for purifying exhaust gas; a catalyst heat insulation control section 52 that performs catalyst heat insulation control to suppress a decline in temperatures of the catalysts 31, 32 by reducing intake air amount during an idle operation; discharge amount storage sections 84A, B that acquire and store beforehand the amounts of HC and CO discharged from an internal combustion engine 10 when the catalyst heat insulation control is performed in the idle operation state; heat generation amount estimation sections 88A, B that estimate HC and CO heat generation amounts of the catalysts 31, 32 on the basis of the amounts of HC and CO read from the discharge amount storage sections 84A, B during execution of the catalyst heat insulation control; and catalyst temperature estimation sections 88C, D that estimate temperatures of the catalysts 31, 32 on the basis of the HC and CO heat generation amounts estimated by the heat generation amount estimation sections 88A, B.SELECTED DRAWING: Figure 10 |
