Effective 1D Model Reflecting the Impact of Deposited Soot on Coupled Reaction and Transport Inside the Catalytic Filter Wall

This paper proposes an extension of the 1D+1D model for a catalytic monolith filter used in exhaust gas aftertreatment, which allows for the prediction of the effects that soot deposits formed inside the filter wall can have on the catalytic conversion of exhaust gas components. The soot deposits act as an additional barrier between the flowing gas and catalytic sites. The extended model considers three characteristic lengths for diffusion: (i) through the soot deposits, (ii) through the remaining free pores, and (iii) through the catalytic coating. The diffusion resistance of each part is considered based on the corresponding characteristic length and local effective diffusivity. The simulations predict no influence of soot on the reaction onset but an increased slip of unreacted gas above the light-off temperature, particularly at higher flow rates. The predicted trends are consistent with the observations reported in the literature.