| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device 1 capable of estimating an appropriate amount of PM deposition PMdep (a cumulative amount of deposition ΣPMdep) despite operation for a long period of time.SOLUTION: This invention relates to an exhaust emission control device 1 which comprises a soot filter 8 and an oxidation catalyst 9, for oxidizing nitric oxide contained in an exhaust emission of an engine 2 with the oxidation catalyst 9 into nitric dioxide, collecting PM contained in the exhaust emission of the engine 2 with the soot filter 8, and oxidizing and removing the collected PM with the nitric dioxide. The exhaust emission control device 1 calculates an internal temperature t3 of the oxidation catalyst 9 in reference to an inlet temperature t1 and an outlet temperature t2 of the oxidation catalyst 9, calculates a reference catalytic efficiency α of the oxidation catalyst 9 in reference to the internal temperature t3 and an exhaust flow rate Ex of the engine 2, calculates a deterioration coefficient (1-Σβ) of the oxidation catalyst 9 on the basis of the internal temperature t3 and an accumulated operation time T for which the oxidation catalyst 9 is exposed to the exhaust emission, and then calculates a deterioration coefficient γ that is the present catalytic efficiency of the oxidation catalyst 9 in reference to the reference catalytic efficiency α and the deterioration coefficient (1-Σβ).SELECTED DRAWING: Figure 4 |
