Validation of a standardized measuring journal for calibration of exhaust gas after treatment catalysts - Investigation of the effect of hydrocarbon species on SCR catalyst behaviour

In Research & Development, the simulation of the aftertreatment systems has become a fundamental part in the development process for the automobile industry. It is normal then to study individually every aftertreatment technology in order to create simulation models for these technologies such as Selective Catalytic Reduction (SCR), Diesel Oxidation Catalyst (DOC) or Diesel Particle Filter (DPF). For helping the creation of these models, dedicated experiments are carried out. These kinetic experiments must be designed and well-defined such that they provide the necessary information in a reproducible way at minimal time and costs. In the first part of the work and in order to facilitate measurements with long SDPF specimens, a reactor with a new oven design has been characterized. Its thermal behaviour and the absence of unwanted reactions of the bare reactor (without catalyst) have been checked. In a previous work, dedicated kinetic measurement procedures for the SCR calibration process were determined and optimized on a synthetic gas test rig. The optimal settings and procedures were programed in the test rig control software. In the second part of this work, several measurements based on these optimal procedures have been carried out on the test rig with a state-of-the-art Cu-Ze SCR to investigate the influence of several types of HCs on the SCR behaviour. The alternative of the NO2/NOx ratio step concept was used for the NOx conversion study of the SCR catalyst. It has been seen that the presence during the experiment of different HC species such as C3H6 and C2H2 had an negative effect in the NOx reduction, and for other HC species as C3H8 the effect was practically inexistent. The results of this work will help to better understand the behaviour of SCR catalysts and SDPF filters for future investigations.Outgoin