NH3-SCR on Fe zeolite catalysts – From model setup to NH3 dosing

The setup of a detailed model for the NH3-SCR process on iron exchanged zeolite catalysts is described, which takes into account the reactions of NH3, NO and NO2 occurring under typical exhaust conditions. Validation experiments for a standard SCR gas mixture show that the model is able to describe the dynamic behaviour of this system at transient temperature conditions. The model is used for the parameterization of an ammonia dosing controller. To prove the functionality of this controller it was implemented on a synthetic gas test bench and tested by a dynamic temperature experiment. This setup allows the evaluation of the parameterized controller without any disturbances from engine or injection effects.