Experimental Studies of an Advanced Ceramic Diesel Particulate Filter 2008-01-0622
A Cummins ISB 5.9 liter medium-duty engine with cooled EGR has been used to study an early extrusion of an advanced ceramic uncatalyzed diesel particulate filter (DPF). Data for the advanced ceramic material (ACM) and an uncatalyzed cordierite filter of similar dimensions are presented. Pressure drop data as a function of mass loadings (0, 4, and 6 grams of particulate matter (PM) per liter of filter volume) for various flow rate/temperature combinations (0.115 - 0.187 kg/sec and 240 - 375 °C) based upon loads of 15, 25, 40 and 60% of full engine load (684 N-m) at 2300 rpm are presented. The data obtained from these experiments were used to calibrate the MTU 1-D 2-Layer computer model developed previously at MTU. Clean wall permeability determined from the model calibration for the ACM was 5.0e-13 m2 as compared to 3.0e-13 m2 for cordierite. The calibrated model was then used to predict the pressure drop of the ACM and cordierite substrates for the same channel dimensions (width and thickness). From these calculations at 40% engine load, the total pressure drop for the ACM were 18, 33 and 34% lower as compared to cordierite at 0, 2 and 4 g/L PM loading.
Active regeneration experiments with the ACM and cordierite substrates were conducted at 4 and 6 grams of PM/liter for a diesel oxidation catalyst (DOC) outlet temperature of 600 °C. Diesel fuel was injected after the turbocharger outlet with a DOC before the DPF. Results on the pressure drop and temperatures during the regeneration of the substrates are presented and discussed along with the final mass of PM oxidized. PM oxidation efficiencies, average oxidation rates and grams of PM oxidized per liter of fuel consumed were similar for the ACM and cordierite substrates during active regeneration.
Tests under uncontrolled regeneration conditions were performed with the ACM and cordierite substrates for a PM loading of 4.5 g/L. The DPF temperature was raised to 600 °C by active regeneration and then the transition to idle was made prior to significant oxidation of PM in the DPF's. The temperatures and pressure drops across the DPF's were measured during the initiation of passive and active regenerations and transition to idle. After remaining at idle and after the pressure drop and temperatures stabilized, the DPF was reweighed and the mass of PM oxidized was determined. Results on the pressure drop and temperatures during the uncontrolled regeneration of the substrates are presented.