Modelling soot deposition and monolith regeneration for optimal design of automotive DPFs

Diesel particulate filters (DPFs) are extruded monoliths comprising many square channels. The material of the monolith, and the size and shape of channels require optimization to guarantee best performances. In this work, we develop an original semi-analytical model to analyze filter behavior during both loading and regeneration operations. Fluid flow and pressure drop along/across monolith channels are calculated based on lubrication theory and Darcy sub-model. Time evolution of filter properties induced by soot deposition and cake formation is modelled using a unit collector sub-model. Cake burn-out and the thermal response of the monolith during the regeneration stage is modelled using a simplified soot combustion and heat transfer sub-model. The impact of channel number and size, filter hydraulic permeability and thermal capacity on back-pressure build-up, regeneration efficiency and risk of thermal failure are discussed to improve the design of automotive DPFs.