The Filtration and Particulate Matter Oxidation Characteristics of a Catalyzed Wall-Flow Diesel Particulate Filter: Experimental and 1-D 2-Layer Model Results

A 1-D 2-layer model developed previously at MTU was used in this research to predict the pressure drop, filtration characteristics and various properties of the particulate filter and the particulate deposit layer. The model was calibrated and validated for this CPF with data obtained from steady state experiments conducted using a 1995 Cummins M11-330E heavy-duty diesel engine with manual EGR and using ULSF. The CPF used is a NGK filter having a cordierite substrate with NEX catalyst type formulation (54% porosity, 15.0 μm mean pore diameter and 50 gms/ft³ Pt). The filter was catalyzed using a wash coat process. The model was used to predict the pressure drop, particulate mass retained inside the CPF, particulate mass filtration efficiency and concentration downstream of the CPF with agreement between the experimental and simulated data. The model was also used to predict the clean substrate permeability, packing density of the particulate deposited inside the substrate, permeability and packing density of the particulate layer deposited on the substrate, activation energies and frequency factors for the thermal and catalytic oxidation path and the thickness of the particulate layer I, which is in contact with the catalyst. In addition, the model also predicted the velocities in the inlet channel, outlet channel and through the wall, variation of particulate layer thickness with axial distance and time along with the particle number distribution downstream of the CPF.