Measurement and Prediction of Filtration Efficiency Evolution of Soot Loaded Diesel Particulate Filters

Experimental and theoretical methods are presented to characterize the transient filtration efficiency (FE) behavior of Diesel Particulate Filters (DPFs) exposed to soot laden exhaust gas streams under laboratory and engine exhaust conditions. A (1+1) dimensional transient model, comprising a one dimensional channel model in combination with a one dimensional wall microstructure model is presented to study the sensitivity of the FE behavior on DPF microstructure and geometry properties, along with the impact of the hydrodynamic and aerosol flow conditions (flow rate, temperature, aerosol characteristics). The dynamic model also considers the dynamic soot oxidation by passive regeneration. The model has been validated through use of an extensive set of experimental data obtained under different operating conditions and with DPFs of different microstructure. Evolution of dynamic FE under dynamic engine operating conditions, including the typical emission cycles (FTP, WHTC, etc.) is predicted and the results are compared with the experimental measurements of mass based filtration efficiency. In general, the predictions from the model have been found to be in good agreement with the experiments.