For highly sensitive injection systems – super clean fuel filters from the MANN-FILTER clean room

Ludwigsburg (DATE) – modern diesel engines and their injection systems are sensitive to impurities and water in fuel. Even microscopically small particles can cause great damage. For this reason, MANN-FILTER offers fuel filters with high filtration efficiency and effective water separation which reliably protect all components. As cleanliness requirements increasingly extend to the components themselves too, MANN+HUMMEL is manufacturing more and more fuel filters which meet particularly high specifications in the clean room of the production facility in Marklkofen. The filters produced in this way receive a purity seal and are available to workshops and distributors in the independent aftermarket.

Clean room production at MANN+HUMMEL in Marklkofen

MANN-FILTER fuel filters with purity seal

The automotive industry has in recent years developed engines and direct fuel-injection systems which can precisely dispense small quantities of fuel and thus keep fuel consumption as low as possible. Such common- rail injection units are delicate, high-tech systems. The injection pump generates pressure of up to 2,500 bar, the injection nozzles are smaller than 0.1 mm in diameter, that is, almost as fine as a human hair. This demands clean fuel, as even the smallest contaminant particles can cause serious damage to the injection system and impair its performance. High-quality fuel can however also be contaminated in western industrialised countries. Tiny splinters of metal or plastic and other particles can enter the diesel fuel when filling up, during transport or storage, or through abrasion. In order to protect the engine’s sensitive fuel injection system, MANN-FILTER is consistently increasing the filtration efficiency of its fuel filters, which reliably retain extremely small particles, only a few microns in diameter. Contaminants barely visible to the naked eye - dust from the Sahara is many times larger.

Component cleanliness: clean and be clean
The filter should not in fact just purify the fuel, it must also be very clean. Many vehicle manufacturers have now set strict requirements with regard to component cleanliness. MANN+HUMMEL has thus established Component Cleanliness Management (CCM) within the company. This concept takes cleanliness specifications into account in product development and in all processes, from purchasing and production right through to delivery to customers. ‘The filter supplies clean fuel to the high-pressure part of the injection system. It must however be clean when it is fitted on the clean side, to prevent contaminant particles disturbing the highly sensitive system when the engine is started for the first time,’ explains Melanie Michler, Fuel Filters Product Manager at MANN-FILTER. To produce components which meet particularly high standards of cleanliness, ultra-modern clean room manufacturing facilities have been set up by the filtration specialists at the plant in Marklkofen, Bavaria. Even large-volume series can be produced in the clean room of the world’s largest filter plant.

Dust doesn’t stand a chance in the ‘white area’
Filter components are assembled in a special room, accessible only to trained personnel. Protective clothing must meet strict hygiene rules. Clean room shoes, white lab coat, gloves and hairnets are mandatory. The room itself is certified to EN ISO 14644. Just as in the pharmaceutical and food industries, the ceilings, walls and floors in the so-called ‘white area’ are overlaid with dirt-resistant, powder coated steel sheet. Only designated tools for this area may be used here. The air pressure is somewhat higher, to prevent ingress of dust. Fibrous particles that can arise during production are directly sucked away in situ. Filters leaving this clean room are protected on the clean side with a CCM seal.

Practical tip for the workshop
Care must be taken when fitting fuel filters with a CCM seal. Melanie Michler recommends: ‘Only take the filter out of stock shortly before installation, then remove the purity seal and install the filter immediately. Changing these filters requires a clean environment and clean hands. It is also important to avoid any additional dust in the immediate vicinity when changing the filter. This will effectively prevent contamination on the downstream side’.

Finer filtration, larger dust holding capacity, longer service life
Clean room production of MANN-FILTER products in Marklkofen has increased tenfold since 2009. The PU 9003 filter element, supplied to customers, including Volvo Cars, is also manufactured there. The OEM installs this fuel filter into its 2.4 litre diesel engines. The element contains high-efficiency MULTIGRADE F_HE filter media which retains, in accordance with ISO Standard 19438, at least 95% of contaminant particles 0.004 microns in size and over 95% of water. MULTIGRADE F is one of a family of multi-layer high-tech filter media developed by MANN+HUMMEL which meet the increasingly demanding requirements of the vehicle manufacturers. The specialists from Ludwigsburg achieve higher filtration efficiency by combining a cellulose carrier medium with a synthetic meltblown layer. After passing the first layer of ultrafine meltblown plastic fibres, the unfiltered fuel flows through a second, very dense cellulose layer. The dust holding capacity is substantially increased, compared with conventional cellulose media.

Tracking down tiny water droplets
Diesel absorbs water from the ambient air. Even tiny concentrations of water in fuel can damage downstream units such as pistons, the cylinder head, injection nozzles, fuel lines and the injection pump and impair engine performance. Almost complete water separation provides important protection against corrosion. Here too, the meltblown layer of the MULTIGRADE F media is extremely effective, thanks to its hydrophobic properties. Water sensors on vehicles indicate when the separated water is due to be emptied. This is generally done through a drain screw on the filter housing. With the PU 9003 filter element, MANN+HUMMEL is also helping to protect the environment. It is completely metal-free, and as it can be fully incinerated, it can be disposed of in an environmentally friendly way.

One filter brand – 97% market coverage in Europe
With over 97% market coverage in Europe, the MANN+HUMMEL portfolio contains suitable filters for virtually every model of passenger car and transporter. The MANN-FILTER products impress through their OE quality and fast availability.


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Photo:                        MANN-FILTER fuel filters with purity seal
                                    Clean room production at MANN+HUMMEL in Marklkofen

Contact:                     Miriam Teige
                                    Telephone:     +49 (0) 7141 98-3354
                                   E-mail: miriam.teige@mann-hummel.com 

The MANN+HUMMEL Group is a leading global expert for filtration solutions and development partner and original equipment supplier to the international automotive and mechanical engineering industries. Employing 14,575 people at more than 50 locations worldwide, the company achieved turnover of about 2.6 billion euros in 2012. The group’s product portfolio includes air filter systems, intake manifold systems, liquid filter systems, cabin filters and plastic sound components (known as 'symposers'), as well as filter elements for vehicle servicing and repair. For general engineering, process engineering and industrial manufacturing sectors the company’s product range includes industrial filters, a series of products to reduce carbon emission levels in diesel engines, membrane filters for water filtration and filter systems.