Evaluation of a DPF Regeneration System and DOC Performance Using Secondary Fuel Injection 2009-01-2884

An active diesel particulate filter (DPF) regeneration system is evaluated, which applies secondary fuel injection (SFI) directly within the exhaust system upstream of a diesel oxidation catalyst (DOC). Diesel fuel is oxidized in the presence of a proprietary catalyst system, increasing exhaust gas temperatures in an efficient and controlled manner, even during low engine-out gas temperatures. The exotherms produced by secondary fuel injection (SFI) have been evaluated using two different DOC volumes and platinum catalyst loadings. DOC light-off temperatures were measured using SFI under steady-state conditions on an engine dynamometer. A ΔT method was used for the light-off temperature measurements – i.e., the minimum DOC inlet gas temperature at which the exothermic reaction increases the outlet gas temperature 20°C or greater than the inlet temperature. All four of the DOCs tested exhibited similar exothermic behavior in achieving the 650°C target temperature at selected engine operating conditions. Analysis of an engine-tested DOC by X-ray diffraction, as well as the measurement of its conversion efficiencies for oxidation of CO, C₃H₆ and NO using a laboratory flow reactor are also reported.