A numerical model to simulate the filtration and oxidation of PM as well as the oxidation of NO, CO and HC in a CPF was developed in reference [1]. The model consists of parameters related to filtration and oxidation of PM and oxidation of NO, CO and HC. One of the goals of this paper is to use the model to determine the PM and gaseous species kinetics for ULSD, B10 and B20 fuels using data from passive oxidation and active regeneration engine experimental studies.
A calibration procedure to identify the PM cake and wall filtration parameters and kinetic parameters for the PM oxidation and NO, CO and HC oxidation was developed. The procedure was then used with the passive oxidation [2] and active regeneration [3] engine data. The tests were conducted on a 2007 Cummins ISL engine with a DOC and CPF aftertreatment system. The simulation results show good agreement with the experimental CPF pressure drop, PM mass retained measurements and the outlet NO, NO2, CO and HC concentrations. The results show that for both NO2-assisted and thermal PM oxidation, the reactivity of PM increases with increasing biodiesel blend level. The NO2-assisted PM oxidation in the wall showed higher reaction rate constants compared to the PM cake, but with the same activation energy. The identified PM oxidation kinetics were used to perform a parametric study of the effect of NO2 concentration and temperature on the reaction rate and in turn to show how NO2-assisted PM oxidation can be increased and used in active regeneration to reduce fuel consumption.