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Catalysts for Lean-Burn Engine Exhaust Aftertreatment Using Hydrocarbon Selective Catalytic Reduction
ISSN: 1946-3952, e-ISSN: 1946-3960
Published November 02, 2009 by SAE International in United States
Citation: Schmieg, S., Sloane, T., and Blint, R., "Catalysts for Lean-Burn Engine Exhaust Aftertreatment Using Hydrocarbon Selective Catalytic Reduction," SAE Int. J. Fuels Lubr. 2(2):323-336, 2010, https://doi.org/10.4271/2009-01-2819.
Unique silver/alumina catalysts developed in collaboration with BASF Corporation were investigated at General Motors under simulated lean-burn engine exhaust feed conditions for the selective catalytic reduction of NOx using hydrocarbons as reductant (HC-SCR). Catalysts were evaluated using a laboratory fixed-bed flow reactor system over a wide range of temperatures relevant to light-duty and heavy-duty exhaust conditions for CIDI (compression ignition direct injection – diesel) and SIDI (spark ignition direct injection – gasoline) applications. This report investigates the effects of silver content (i.e., wt.% Ag2O) and reductant composition (i.e., simulated diesel fuel, simulated gasoline, ethanol, and ethanol/simulated gasoline mixtures) on the steady-state NOx reduction activity. A dual catalyst approach using a HC-SCR catalyst followed by an NH3-SCR catalyst was also investigated. Stochastic Process Modeling was used to determine the optimum in-exhaust injection strategy using ethanol and simulated gasoline as reductants during the New European Driving Cycle.