EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To execute a reviving process for the SOx absorbing agent at an appropriate time in an exhaust emission control device comprising an SOx absorbing agent upstream of an NOx catalyst. SOLUTION: An SOx sensor 24 and an NOx catalyst 20 are provided downstream of an SOx absorbing agent 17. At the time of rich spike immediately after reviving the SOx absorbing agent 17, the SOx concentration in the exhaust gas downstream of the SOx absorbing agent 17 is detected by the SOx sensor 24. Based on the size of the SOx concentration, the state (degree) of the thermal deterioration of the SOx absorbing agent 17 is judged so that frequency of reviving the SOx absorbing agent 17 is increased according to the progress of the thermal deterioration.