Patent ID: 8813479

Claim:
A method for an aftertreatment system, the aftertreatment system including a catalyst disposed upstream of a particulate filter, comprising: conducting soot regeneration of the particulate filter under a selected operating condition; determining whether a soot regeneration frequency of the particulate filter is greater than a threshold frequency; initiating a sulfur regeneration of the aftertreatment system based on the soot regeneration frequency of the particulate filter being greater than the threshold frequency; determining whether the soot regeneration frequency of the particulate filter is less than the threshold frequency after the sulfur regeneration of the aftertreatment system; conducting non-regeneration operation of the aftertreatment system based on the soot regeneration frequency of the particulate filter being less than the threshold frequency after the sulfur regeneration of the aftertreatment system; and continuing sulfur regeneration of the aftertreatment system if the soot regeneration frequency of the particulate filter is greater than the threshold frequency after sulfur regeneration of the aftertreatment system and indicating degradation of the catalyst if a number of sulfur regenerations initiated responsive to the soot regeneration frequency is greater than a threshold number.