A lumped parameter model for diesel soot morphology evaluation and emission control

Diesel engine emission standards have become more and more severe in recent years. The use of diesel particulate filters (DPFs) is a consolidated technology to reduce the emission of particulate matter out of such engines. This work is aimed at presenting a global lumped parameter for onboard applications to estimate soot morphology and its effects on DPF performances. Starting from diesel soot production during combustion, soot morphology is evaluated in terms of fractal dimension and radii of gyration. The morphology of particulate matter influences the permeability of soot deposit inside the DPF: the growth of soot layer and the consequent pressure loss are evaluated during the loading phase in different sections of the trap. Finally, the temperature trend during regeneration is computed, as a function of the amount of soot accumulated in the different zones of the DPF. The results are compared to experimental measures from the literature and to 3D-computational fluid dynamics (3D-CFD) simulations.