Relationship between Pressure Drop and Pore Microstructure for Diesel Particulate Filters from Experimentation and Capillary Pore Modeling

Gregory  Merkel, Corning

The pressure drop of ceramic DPFs is important for fuel economy, engine performance, and regeneration control strategy.  For a given filter geometry and flow condition, the pressure drop versus soot-loading behavior depends strongly upon the pore microstructure of the bare or catalyzed ceramic.  Experimental pressure drop measurements as a function of flow rate and artificial soot loading for a wide variety of filter materials are used to derive quantitative relationships among clean and soot-loaded pressure drop, permeability of the clean and soot-containing wall, and the porosity and pore size distribution of the ceramic.  These observations are supplemented with permeability and pressure drop calculations based upon theoretical models that approximate the ceramic pore microstructure by randomly oriented capillary pores of uniform diameter.  Differences in pressure drop behaviors are interpreted in terms of the location and packing density of the soot within, and on the surface of, the filter walls.