PM Reduction Performance and Regeneration Characteristics of Catalyzed Metal Foam Filters for a 3L Diesel Passenger Vehicle

Exhaust gases of diesel vehicles are considered as a major reason of city air pollutions. The DOC(Diesel Oxidation Catalyst) and DPF(Diesel Particulate Filter) have been used to reduce the emissions of diesel vehicles. The DOC can oxides HC, CO and SOF(Soluble Organic Fraction) in the PM emissions, and the DPFs can filter the most of solid PM, such as carbon particles. As the DPFs, wall flow type ceramic honeycomb filters have been commonly used and now being still advanced. However, the cost and durability of the currently used DPFs are not perfect yet. Metal foam is the one of promising materials for the DPFs due to its cost effectiveness, good thermal conductivity and high mechanical strength. The metal foam can be produced with various pore sizes and strut thickness and finally can be coated with catalytic wash-coats with low cost. A number of foam filters of different pore size and filtering volume are tested in an engine bench and this paper shows the filtration and pressure drop characteristics of the metal foam filters. This paper also shows the effect of catalyst loading amount on the passive regeneration characteristics of the metal foam filter and compares with that of conventional wall flow type ceramic honeycomb filters.

Key words: DPF(Diesel Particulate Filter Trap), Metal Foam Filter, PM(Particulate Matters), Filtration efficiency, Pressure drop, Regeneration