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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.

The use of biofuels in internal combustion engines changes the composition of the engine exhaust gas. When burning a biofuel blend, significant amounts of oxygenated hydrocarbons such as alcohols, ethers and aldehydes are present in the exhaust gas. It is known, that these compounds influence catalytic processes in exhaust gas converters. In this work we propose a global kinetic model for ethanol and acetaldehyde oxidation on commonly used Pt, PtPd and Pd-based catalytic oxidation converters of automobile exhaust gases. The mechanism is based on two steps: (i) partial oxidation of ethanol to acetaldehyde, and (ii) complete oxidation of acetaldehyde to CO₂ and H₂O. Kinetic parameters of ethanol and acetaldehyde reactions are evaluated on the basis of laboratory light-off experiments with several catalytic monolith samples (noble metal loading 9-140 g/cft; Pt, Pd, and PtPd; at space velocity 30 000-240 000 h-₁).