Metal Fibre Diesel Particulate Filter : Function and Technology 2005-01-0580
A number of different filter media using various kinds of materials have been developed since the end of the 1970's. Up to now filters made of steel wool, cordierite, silicon carbide, sintered metals and metal and ceramic fabrics have been used. Problems with inadequate durability due to the high mechanical and thermal stresses, new requirements for the filter material, such as high filtration efficiency for nano-particulates (10 - 50 nm) at minimum pressure loss, a longer working life and a low cost level have triggered the development of new filter materials . This paper describes the performances of a new diesel particulate filter based on metal fibre medium.
The metal fibre medium is a non-woven, pleatable medium with a three dimensional, felt-like structure. The filtration fibre media are made of sintered Fe-Cr-Al alloy metal fibres, based on combinations of bundle drawn fibres and shaved Bekinit® fibres. In the application of Diesel Exhaust Particulate Filtration based on a multi-layer metal fibre fleece, the capturing of the PM happens inside of the medium and not on the surface of the medium. As such this technology enables large dirt holding capacities (PM and ash) with a thin light-weight medium, while low pressure drop is maintained.
Most of the filter trap issues are related to the filter regeneration method and to its compatibility with the filter material. It can be shown that due to the material properties of the metal fibre media, the regeneration is easier.