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[October 2009]
Mann+Hummel Enters Ceramic Diesel Particulate Filter Market
Mann+Hummel GmbH (Ludwigsburg, Germany) has entered the market for ceramic diesel particulate filters. The new filter offers greater scope with regard to design and improved filtration performance. Production at a pilot installation in Ludwigsburg will commence at the end of 2009, manufacturing around 60,000 filters per year. Large-scale production is planned for 2012.
In order to comply with current and future legislation on emissions, particulate filters are installed in virtually all modern diesel engines. These filters, which are usually made of special ceramics, retain virtually 100 percent of the soot particles in the combustion engine’s exhaust system. In particulate filters, the exhaust gases flow into a network of alternatively closed channels. When these gases pass through the filter’s porous ceramic walls, the small soot particles are retained. The accumulated soot is completely incinerated in regular regeneration cycles, restoring the full storage capacity of the filter.
The company employed a novel concept to produce its own diesel particulate filter. Instead of the currently used cordierite and silicon carbide, the new filter contains aluminium titanate, an aluminium and titanium ceramic oxide compound. This has a higher temperature resistance than cordierite and does not expand as significantly as silicon carbide. Through these properties, it is possible to produce a temperature-resistant one-piece filter.
Mann+Hummel can draw on years of experience in the manufacture of compact air filter elements here. An amended type of paper compact air filter is used as a carrier medium for the new diesel particulate filter. Just as with air filters, the filtration specialist creates homogenous paper media through applying a coiling technique. During production, Mann+Hummel utilises innovative CCP (Ceramic Coated Paper) technology. The paper carrier medium is immersed in a ceramic suspension which completely surrounds the paper fibres. The finished diesel particulate filter is produced after cauterising the paper and at the same time sintering the ceramic particles. As a ceramic adhesive is inserted between the layers of paper during the coiling process, the channels are alternately closed automatically – an essential pre-requisite for filtration. At the end of the new production process, the diesel particulate filter is complete.
The company explained that compared with the diesel particulate filters currently on the market, the future Mann+Hummel product offers, amongst other things, improved storage capacity for soot particles. In addition, it is possible to reduce CO2 emissions through lower exhaust gas back pressure. The new development gives the design engineers greater scope, as far as installation space and design are concerned. As the shape and size of the filter depend only on the type of paper carrier medium and coiling technique used, the new product will offer greater flexibility and additional opportunities, particularly with regard to channel geometry and filter shape. It will be possible to change the number and geometry of the filter channels more quickly and easily, so that conical channels and openings between the channels could be feasible.
The new concept should also provide greater opportunity to integrate additional functions. Furthermore, it should also be possible to integrate a catalytic converter into the filter body, thus reducing the number of components and the installation space required.
ENDS