Patent ID: 8794057
Filing Date: 2014-08-05
Classification: F01N,Y02T

Abstract:
1. A method of determining aging of a diesel oxidation catalyst (DOC) in an engine exhaust system comprising: receiving a first sensor signal from a first nitrogen oxides (NOx) sensor positioned in exhaust flow upstream of the DOC; wherein the first sensor signal is indicative of an amount of NOx in the exhaust flow upstream of the DOC; receiving a second sensor signal from a second NOx sensor positioned in the exhaust flow downstream of the DOC; wherein the second sensor signal is indicative of an amount of NOx in the exhaust flow downstream of the DOC; calculating via a controller a difference between the first sensor signal and the second sensor signal; determining via the controller whether at least one predetermined operating condition is satisfied; determining via the controller a DOC aging level based on a predetermined correlation between the calculated difference and DOC aging only if the predetermined operating condition is satisfied; determining a mass flow rate of NOx flowing past the first NOx sensor based at least partially on the first sensor signal; determining an amount of time over which a predetermined amount of NOx passes the first NOx sensor at the mass flow rate; periodically receiving additional sensor signals from the first and the second NOx sensors during the amount of time; and wherein said calculating the difference includes averaging differences between the first and the second sensor signals and the additional sensor signals periodically received during the amount of time.