Technical Paper
Design and Durability of Vanadium-SCR Catalyst Systems in Mobile Off-Road Applications
2011-04-12
2011-01-1316
The emission regulations for mobile off-road applications are following on-road trends by a short delay. The latest Stage 3B and 4 emission limits mean a gradual implementation of oxidation and SCR catalysts as well as particulate filters with off-road machines/vehicles in the 2010s. The driving conditions and test cycles differ from on-road truck applications which have been the first design base for off-road aftertreatment technologies. Aftertreatment systems for Stage 4 were first analyzed and they will include oxidation catalysts, a NOx reduction catalyst (SCR or LNT), a particulate filter and possibly units for urea hydrolysis and ammonia slip removal. The design and durability of V₂O₅/TiO₂-WO₃ catalysts based on metallic substrates were investigated by engine bench and field experiments. NOx emissions were measured with 6.6 and 8.4 liters engines designed for agricultural and industrial machinery.
