Modern diesel injection systems rely on fuel that is almost completely free of dirt particles and water. In practice, however, drivers are often confronted with dirty and water-contaminated diesel fuels.

Filtration experts at MANN+HUMMEL, development partner and original equipment supplier for the international automotive industry, have solved this problem with a new, multi-layer, high-performance filter media that is four times more efficient than conventional filter papers.

"The fuel filter plays a key role in the implementation of diesel drive technology," said Dr. Ing. Gunnar-Marcel Klein, head of MANN+HUMMEL’s oil and fuel filtration development, during the recent sixth International Car Symposium in Bochum, Germany. Released under the name MULTIGRADE F, the new diesel fuel filter has been under development for passenger and commercial vehicles during the past few years.

MANN+HUMMEL developed the simulation tools used to calculate the particle separation in the microscopic fiber structure of filter media. With ultra- small particles that are between three and five microns, MULTIGRADE F will improve today’s initial filtration efficiency from 85-99 percent to 95-99.9 percent.

The increasingly global use of modern diesel technology is spurring the development of high-performance diesel fuel filters, such as MANN+HUMMEL’s MULTIGRADE F. Another technology driver involves rising injection pressures in future common-rail diesel systems, so fuel filter performance must double or quadruple.

MANN+HUMMEL significantly increased diesel fuel filter performance by using melt-blown, superfine fibers combined with a compressed cellulose substrate layer. This multi-layer filter media (also called a "fleece") was optimized to greatly increase oil performance and air filter elements.

"The knowledge and experience we gained by developing MULTIGRADE F will secure MANN+HUMMEL’s position as a technological leader," Klein said.

As the automotive industry changes from using paper to high-performance fleece filter media, there will be opportunities to increase engine-oil wear protection in the future and create more compact filter designs.

The world’s first fleece oil filter, utilizing the two-layer MULTIGRADE O_SYN medium, was developed by MANN+HUMMEL for Mercedes-Benz. The company also is supplying a fleece air filter with the high-performance gradient media MICROGRADE N for the Audi A8.

The MANN+HUMMEL Group is an international company. In 2005, the company achieved sales of approximately $1.6 billion. The MANN+HUMMEL Group employs about 9,300 people at more than 41 locations worldwide. The company develops, produces and sells technically complex automotive components such as air- filter systems, intake-manifold systems, liquid-filter systems and cabin filters for the automotive industry, and filter elements for vehicle servicing and repair.

For general engineering, process engineering and industrial manufacturing sectors, the company’s product range includes industrial filters, filter systems and materials-handling systems and equipment. MANN+HUMMEL’s customers come from a large number of sectors, with series production for the automotive industry occupying a key position.

Anthony Kodack
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