During the planning for the IAA Commercial Vehicles this year in Hanover it came to my mind that we should present our 75th anniversary on the exhibition in an impressive way, because these 75 years indicate at last MANN+HUMMEL’s long tradition for commercial vehicle filtration. Soon, the idea was born to expose historic and current products to show the technical progress, as well as our longtime experience at this area. So, let us glance into the past together to discover how our products developed during the last years.
Air cleaners for widely differing installation spaces
In the past, air cleaners were made from sheet metal and installed on the engine of so-called long-nosed trucks. This vehicle shape is no longer produced in Europe as the current legislation only permits a maximum overall length of 18.75 meters. Regarding to that, the installation position of the air cleaners has changed, so today they are predominantly attached on the chassis. In the course of time sheet metal air cleaners were replaced by more lightweight filters with plastic housings. Thanks to this change of materials, the manufacturing costs compared with the labor-intensive production of a sheet metal filter were reduced significantly.
In order to meet the new emissions limits, new components have been added in recent years. Further, products for recuperating energy from exhaust gases, for example, are set to follow. The resulting ever more restricted installation space can be utilized to best possible effect by MANN+HUMMEL with its innovative air cleaner concepts such as EXALIFE or VarioPleat.
These developments are accompanied by a simultaneous improvement in the filtration characteristics. For instance, until the mid-1970s oil-bath air cleaners were used, today these elements are serial replaced by air filters including paper air filter elements. These do not use axial sealing as in the past, but radial sealing and are metal-free. In addition to being more environmentally friendly, today‘s standard media perform significantly better than the oil-bath air cleaners and achieve a separation efficiency of 99.9 percent. With a nanofiber coating, even a value of 99.98 percent can be achieved. These high separation efficiencies contribute significantly towards reducing wear in modern engines. Under normal operating conditions and depending on the design, service intervals of 240,000 kilometers can be attained.
Compact oil filter modules with integrated functions
MANN+HUMMEL already used an oil filter module in the 6R-1315-23 series Henschel commercial vehicle engine from 1971. The module with two main-flow oil filters and an oil centrifuge, integrated in the bypass flow, had an oil filter replacement interval of 20,000 kilometers and counted among the best of its time.
How much engine technology has developed since then is revealed by a comparison with today‘s engines. MANN+HUMMEL has been supplying an oil filter module for the MX-13 engine to PACCAR since 2005. In the current Euro 6 version, this turbocharged and charge-air cooled inline six-cylinder direct-injection diesel engine develops up to 510 hp. Depending on version and market, the maximum oil change interval is 150,000 kilometers. A determining factor here is the selection of the filter media that not only have to absorb more dirt, owing to the longer service intervals, but also resist the higher oil temperatures and aggressive oil aging products over the entire extended service life.
Nowadays, oil filter modules combining several functions are mostly favored, because of the less available installation space. The bypass flow oil centrifuge of the historic oil module is designed according to the replacement interval of the main flow oil filter element and separates out even the finest particles in order to minimize engine wear. Just how much today‘s exhaust emissions legislation influences module design is impacted by use of large stain- less-steel oil coolers in conjunction with a wax expansion element integrated in the current module. The latter controls the rate of the oil volume flow through the cooler, ensures optimal operating temperatures and minimizes fuel consumption.
Efficient fuel filter modules
Modern fuel filter modules are perfectly tailored to the available installation space and in addition to filtration integrate further functions such as an electric heater for use at low temperatures. Comparison with the historical dual head fuel filter with a modern fuel filter module for the medium-duty engine generation illustrates this multifunctional development. Due to this fact, today‘s modules not only serve as carriers for further components, but also as fuel distributors.
Let me illustrate this development by way of example and for that let us get back to the historical Henschel engine. This engine operated with an injection pressure of 200 bar, whereas modern systems achieve injection pressures of 2,500 bar in order to reduce fuel consumption and CO2 emissions. With these fuel filters, the replacement intervals as well as the requirements for separating the water and dirt contained in the fuel have increased immensely.
For that reason, MANN+HUMMEL offers filtration solutions in the shape of prefilters and main filters that reliably protect the injection systems with highly efficient media. If a three-stage fuel filter element is also integrated in the prefilter, it protects not only the high-pressure pump, but also the low-pressure pump against corrosion and dirt. Thanks to this development, MANN+HUMMEL currently acts as leader in the field of three-stage water separation and we’re going to exploit all of these experiences to further consolidate the company’s position as a leading filtration expert in the international automotive and mechanical engineering industry.
Due to the fact that my dad worked for more than 40 years for the company Henschel I sometimes reveled in childhood memories during the preparation for the IAA. His fascinating tales of great engines and their trials inspired me early and certainly they influenced my career choices. During my internship in 1986, I myself disassembled a bigger brother of a truck motor at the company Henschel. Afterwards I reconditioned and rebuilt it; subsequently I retracted it on a test bench and technically accepted it. Recently, I told my dad about the products we’re going to present at the Commercial Vehicles IAA. Trust me; my 86 years old dad directly remembered a lot of these old stories.