EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine capable of suitably recovering the cleanup performance of a NOx purification devise provided downstream of a SOx absorbent without enlarging the device and increasing cost.

SOLUTION: The exhaust emission control device is provided with a SOx trap 13 which is provided at the upstream side of the NOx purification device 17 in an exhaust pipe 4 and of which the SOx desorption temperature is higher than that of the NOx purification device 17; a SOx sensor 16 detecting an SOx concentration of exhaust gas flowing between the SOx trap 13 and the NOx purification device 17 in the exhaust pipe 4; a sulfur purge determination portion 21 that determines whether a sulfur purge desorbing SOx absorbed by the NOx purification device 17 is executed or not on the basis of the SOx concentration detected by the SOx sensor 16; and a sulfur purge execution portion 22 which changes the exhaust gas into a high temperature reducing atmosphere when the sulfur purge determination portion 21 determines to execute the sulfur purge of the NOx purification device 17.

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