System for diagnosing reagent solution quality

摘要

A system for diagnosing the quality of a reagent solution may comprise a reagent solution source for supplying the reagent solution to an emissions catalyst of an internal combustion engine. Means may be provided for determining a quality value corresponding to the quality of the reagent solution. A first filter may receive the quality value and produce a first filtered quality value, and a first comparator may compare the filtered quality value to a threshold and produce a fault value if the first filtered quality value crosses the threshold. Alternatively or additionally, a second filter may receive the quality value and produce a second filtered quality value. A second comparator may compare a difference between the first and second filtered quality values to another threshold and produce another fault value if the difference crosses that threshold.