Patent ID: 8839602
Filing Date: 2014-09-23
Classification: F01N,Y02A,Y02T

Abstract:
1. A method of assessing non-methane hydrocarbon (NMHC) conversion efficiency in a diesel engine after-treatment (AT) system, the method comprising: regenerating the AT system, wherein the AT system includes a diesel oxidation catalyst (DOC) arranged upstream of a diesel particulate filter (DPF); monitoring DOC inlet and outlet temperatures during the regeneration; assessing whether the DOC is operating at or above a threshold DOC efficiency by determining the difference between the DOC inlet and outlet temperatures and comparing the determined DOC inlet/outlet temperature difference with a threshold DOC inlet/outlet temperature difference; monitoring DPF outlet temperature if the DOC is determined to be operating at or above the threshold DOC efficiency; determining the difference between a DOC temperature and the monitored DPF outlet temperature, wherein the DOC temperature is one of the DOC inlet and outlet temperature; assessing whether the NMHC conversion efficiency of the DPF is at or above a threshold NMHC conversion efficiency by comparing the determined DOC temperature/DPF outlet temperature difference with a threshold DOC inlet/DPF outlet temperature difference; determining via a controller that the DOC has failed if the determined DOC temperature/DPF outlet temperature difference is less than the threshold DOC temperature/outlet temperature difference; and generating via the controller a signal indicative of the DOC having failed, if the determined DOC temperature/outlet temperature difference is less than the threshold DOC temperature/outlet temperature difference.