each other and revolved about positive x-axis, producing a 3- D converter with a total of 98235 meshed cells (Figure 12).After successfully modelling and meshing the converter, it was then exported to FLUENT for exhaust gas species analysis. In FLUENT, the substrate was defined as porous media, along with standard wall function treatment, meaning that the reactions with wall surface are included.Comparison of experimental and simulation results were performed at different rpm. A typical comparison is shown in Figures 13 and 14.