Combined SCR/DPF System for Tier 2 LDT
Christine Lambert, Ford Research Labs
Ford Motor Company, with ExxonMobil and FEV, has been participating in the Department of Energy’s (DOE) Ultra-Clean Transportation Fuels Program with the goal to develop an innovative emission control system for diesel sport utility vehicles. The focus on diesel engine emissions was a direct result of the improved volumetric fuel economy (up to 50%) and lower CO2 emissions (up to 25%) over comparable gasoline engines shown in Europe. Selective Catalytic Reduction (SCR) with aqueous urea as the NOx reductant and a catalyzed Diesel Particulate Filter (DPF) were chosen as the primary emission control system components. The program expected to demonstrate more than 90% reduction in particulate matter (PM) and NOx emissions on a light-duty truck/SUV application. Very low sulfur diesel fuel (~15 ppm) enabled lower PM emissions, reduced fuel economy penalty due to the emission control system and improved long-term system durability.
Significant progress was made toward a durable Urea SCR and catalyzed DPF function on a 6000 lb light-duty truck. Development work continued to separately improve Urea SCR and DPF system durability, as well as improved oxidation catalyst function. A total of 120K mi was accumulated on an SCR/DPF system and the potential to meet Tier 2 Bin 5 was assessed.