경유중 황성분이 Metal Foam 필터의 성능에 미치는 영향

The effects of sulfur contents on the performance of the metal foam DPF (Diesel Particulate Filter) were investigated. The metal foam, INCOFOAM? High Temp, was axially stacked in the exhaust pipe to reduce PM emissions. LSD (Low Sulfur Diesel) fuel which has sulfur content of about 300 ppm and ULSD (Ultra Low Sulfur Diesel) fuel which has sulfur content of below 50 ppm were used to compare the emissions. When the DOC (Diesel Oxidation Catalyst) was installed upstream of DPF and the LSD fuel was used, the PM reduction rates at high exhaust temperature were deteriorated because the DOC oxidized sulfur dioxide at high exhaust temperature which eventually forms sulfate particles during dilution. With DOC, BPT (Balance Point Temperature) was lowered from 420℃ to 360℃ due to the NO₂ formation inside the DOC, which is favorable for the DPF regeneration. Accordingly, when ULSD was used, the combination of DOC and DPF showed PM reduction rate of 70% and relatively low pressure difference across DPF, which are acceptable performance for DPF.