Active regeneration experiments were carried out on a production 2007 Cummins 8.9L ISL engine and associated diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF) aftertreatment system. The effects of SME biodiesel blends were investigated to determine the particulate matter (PM) oxidation reaction rates for active regeneration. The experimental data from this study will also be used to calibrate the MTU-1D CPF model [1].
The experiments covered a range of CPF inlet temperatures using ULSD, B10, and B20 blends of biodiesel. The majority of the tests were performed at a CPF PM loading of 2.2 g/L with in-cylinder dosing, although 4.1 g/L and a post-turbo dosing injector were also investigated. The PM reaction rate was shown to increase with increasing percent biodiesel in the test fuel as well as increasing CPF temperature. Additionally, the effectiveness of PM oxidation at a constant CPF temperature (grams of PM oxidized per gallon of dosing fuel) increased with increasing percent biodiesel.
In an analysis of the CPF wall, cake, and channel resistance, it was determined that a correction factor was needed. This correction factor is thought to account for temperature and PM maldistribution in the CPF, exhaust flow maldistribution at the CPF inlet, and changing cake layer permeability during the active regeneration.