Did you know that a truck engine sucks in up to two million litres of air per hour for fuel combustion, depending on the displacement and load? Before the air enters the combustion chamber, it must be cleaned to remove impurities and dust particles. Otherwise, the moving parts of the engine would quickly be subject to wear.
In Europe, where the air is relatively clean, an air filter in a truck can perform for up to 250,000 kilometres. The situation is different in regions such as India, Brazil or China, where long journeys on dusty unsurfaced roads are part of everyday life. Here, a filter can become blocked after just a few weeks. The situation is even more extreme with commercial vehicles used on construction sites or in mines. They have to handle extreme dust exposure, which can mean a daily filter change.
As the cost of purchasing and replacing filter elements contributes to the truck’s running costs, a dust pre-separator is fitted on vehicles which will operate in dusty conditions. As many impurities as possible are thus removed from the intake air before they reach the air filter. Separators, which work according to the cyclone principle, have already been performing this task for many years. Intake air is swirled, impurities are propelled toward the outside by the centrifugal force, removed in a low-flow area and discharged via a valve. This pre-cleaned air then reaches the air filter element. Depending on the design, separation efficiency of between 70 and 90 percent is possible. This significantly extends the service life of an air filter.
That is how dust pre-separation works:
MANN+HUMMEL offers three different types of pre-separator for the commercial vehicle segment. All are maintenance-free and last for the lifetime of the vehicle. If you bear in mind that a pre-separator costs little more than a couple of filter elements, it is also interesting from a cost perspective.
In the most basic version, the two-stage air filter known as PICLON, the pre-separator is integrated in the air filter housing. Here, the air is swirled by means of the tangential inflow. It features a compact design and good separation efficiency of between 70 and 85 percent. It is also extremely robust and cost-effective. Our pipe cyclones, which are usually installed in pairs in the suction duct upstream of the air filter itself, remove up to 85 percent of the dirt particles. This type of cyclone is particularly suitable for European trucks, as we developed it with a good separation efficiency and low pressure loss. Where space is restricted, MANN+HUMMEL offers multi-cyclones, in which multiple small cyclones operate in parallel. Multi-cyclones offer a separation efficiency of over 90 percent. In addition, the modular system can easily be adapted to different installation spaces and levels of air consumption.
Although the principle is simple, its implementation is extremely complex. This is because every component in the engine air intake tract increases pressure loss. Higher pressure loss means that more power is required to draw the air through the air filter system. This in turn has a negative effect on engine power and fuel consumption. We therefore invest a great deal of time, money and engineering into the optimisation of our products. This is partly achieved through customer-independent development, such as the optimisation of cyclones. We also strive to find the best possible solution for every truck in our customer projects. In all cases, the combination of minimal pressure loss, compact design, high separation efficiencies and optimum interplay with the air filter is no coincidence, but the result of extensive development work. This involves developing computer simulations and creating prototypes, which we test extensively on the test rig and in real applications. We then use the results of these tests to continue optimising the product until it meets our demanding requirements.
If you would like to view the effectiveness of the process and see how it actually functions, we would be pleased to show you.
Visit us at the IAA Commercial Vehicles in Hanover which takes place until 2 October. There, you can see our innovations and find out about our filtration products, which we will be demonstrating live at the stand.
You can find us in Hall 13 at Stand B26. I look forward to seeing you there.