EXHAUST EMISSION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE AND THERMAL DEGRADATION ESTIMATING METHOD FOR EXHAUST EMISSION CONTROL CATALYST

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine and a thermal degradation estimating method for an exhaust emission control catalyst capable of suitably estimating thermal degradation by increasing the degree of freedom on the setting of an estimation pattern when the thermal degradation of catalysts is estimated.;SOLUTION: This exhaust emission control device of the engine 1 comprises an exhaust emission control member 30 having an NSR catalyst 31 and a DPNR catalyst 32. A controller 25 calculates the degree of advancement of thermal degradation of the exhaust emission control member 30 in a predetermined time interval based on the floor temperature thereof, and estimates the thermal degradation of the exhaust emission control member 30 based on the integrated value of the calculated degree of advancement of the thermal degradation. When the thermal degradation is estimated, if the numerical treatment capacity of a storage device storing the integrated value of the degree of advancement of thermal degradation is small, the time interval is increased and the degree of advancement of thermal degradation is calculated based on the maximum floor temperature in the increased time interval. On the other hand, if the numerical treatment capacity of the storage device is large, the time interval is reduced and the degree of advancement of thermal degradation is calculated based on an averaged floor temperature in the reduced time interval.;COPYRIGHT: (C)2007,JPO&INPIT