Abstract
The effects of sulfur content on the performance of metal foam DPF were investigated. The INCOFOAM® HighTemp metal foam was used as a substrate material and it was coated with platinum in 2.5g/l with Al2O3 as a carrier. LSD fuel with a sulfur content of 360 ppm and ULSD fuel with a sulfur content of 20 ppm were used as fuels. The chemical compositions of collected PM samples were analyzed using Sohxlet extraction by dichloromethane and Low Mass PM Analyzer by Horiba. The results were compared with DOC which has cell density of 400cpsi/6.5 and Pt loading of 0.7g/l. Because the DOC has higher Pt loading than the metal foam DPF, its light-off temperature was lower than the metal foam filter. Metal foam filter has larger surface area to show better reductions in SOF, HC, CO in high vehicle speeds due to the enhanced diffusion in spite of the low Pt loading. The sulfate emissions were found to be increased when the LSD fuel was used under the high vehicle speeds in both DOC and metal foam DPF. The longer the metal foam DPF was operated at low vehicle speed, the more sulfate was emitted in high vehicle speed. In high vehicle speed, the sulfate emissions are slowly increased until the storage capacity of washcoat for SO3 is reached.
Keywords:Diesel engine, DPF, DOC, ULSD, SOF, Sulfate, Metal foam