Dynamic Model for the Selective Catalytic Reduction of NO with NH3 on Fe-Zeolite Catalysts

Future NOx-emission standards for diesel engines imply an after treatment system, e.g. in the form of an NH₃-SCR system. For the technical realization a sound understanding of the catalytic processes is mandatory. To gain this knowledge a model of the SCR of NO with NH₃ on Fe zeolite catalysts has been developed on the basis of a transient test cycle. The model is able to map the performance of the catalyst both under steady state and transient conditions. As practical examples the model is used to parameterize lookup tables and to compare different formats of lookup tables in terms of suitability for a urea dosage system.