Development of a Methodology to Generate On-Board Diagnostic Threshold Selective
Catalytic Reduction Catalysts for Heavy-Duty Diesel Applications,
Inclusive Dates: 03/15/13 – Current
Background — The on-board diagnostic (OBD) system monitors engine and aftertreatment components that affect the vehicle's emissions performance. When the malfunction illumination light (MIL), also known as the "check engine" light, is illuminated, at least one emission related problem has been detected, and the driver is notified that vehicle service is needed. For heavy-duty diesel engine and medium-duty diesel vehicle applications, the California Air Resource Board (CARB) mandates that heavy-duty OBD systems be implemented for all on-highway engines offered for sale in California beginning with model year 2013. Even though urea-based selective catalyst reduction (SCR) technology has been used as a primary means to meet the US2010 diesel NOx emissions requirements in North America, there is no proven method to consistently create OBD threshold SCR catalysts in the laboratory environment.
Approach — The goal of this project is to answer the industry challenge to develop methodology to consistently age zeolite SCR catalysts to the OBD threshold level. The approach is to use SwRI's FOCAS® burner technology to thermally age the SCR catalysts to the "worst performing acceptable" (WPA) and "best performing unacceptable" (BPU) levels to meet OBD calibration requirements. An existing US2010 certified MY2012 Ford PowerStroke 6.7L diesel engine is being used for the program. The heavy-duty transient FTP cycle has been replicated using the SwRI FOCAS HGTR® system for SCR performance evaluation. An SCR thermal aging cycle has been developed and optimized for aging SCR catalysts to threshold NOx levels. The FOCAS HGTR system is being used to conduct SCR aging and performance evaluations. The FOCAS HGTR generated WPA and BPU SCR catalysts will then be emissions-tested using the Ford PowerStroke 6.7L diesel engine. These tests will validate the proposed SCR catalyst aging methodology.
Accomplishments — It is expected that a novel approach will be developed to generate OBD threshold SCR catalysts. The technical approach will also be further applied as a generic method to age SCR catalysts under precisely controlled operating conditions.