An Experimental Study of Particulate Thermal Oxidation in a Catalyzed Filter During Active Regeneration

Active regeneration experiments were performed on a Cummins 2007 aftertreatment system by hydrocarbon dosing with injection of diesel fuel downstream of the turbocharger. The main objective was to characterize the thermal oxidation rate as a function of temperature and particulate matter (PM) loading of the catalyzed particulate filter (CPF). Partial regeneration tests were carried out to ensure measureable masses are retained in the CPF in order to model the oxidation kinetics. The CPF was subsequently re-loaded to determine the effects of partial regeneration during post-loading.

A methodology for gathering particulate data for analysis and determination of thermal oxidation in a CPF system operating in the engine exhaust was developed. Durations of the active regeneration experiments were estimated using previous active regeneration work by Singh et al. 2006 [1] and were adjusted as the experiments progressed using a lumped oxidation model [2, 3]. Repeat experiments were conducted to evaluate the reproducibility of the experimental data.

In this study a higher global reaction rate for the lowest PM loadings of 1.1 g/L was observed as compared to 2.2 and 4.1 g/L loadings. It was also observed that for the highest PM loading and CPF temperature, the fuel specific PM oxidized was the greatest. Also, active regeneration experiments with shorter durations for similar PM loadings and average CPF temperatures proved more effective in terms of fuel specific PM oxidation. The experimental results were used for calibration of the MTU 1D 2 Layer active regeneration model which is described by Arasappa et al., 2009 [4].