Without them, food would neither get to the consumers, products to the customers, nor production material to the factories. They reach even the remotest of regions and are crucial to our modern logistics. We are talking about trucks: in Germany alone, they carry almost three quarters of all the goods transported and cover distances in the order of 70 billion kilometers in total each year. And the trend is on the rise: “We expect the truck, especially in long-distance hauling, to become even more crucial,” explains Matthias Fix, who is responsible for the sales of commercial vehicle products at MAHLE. According to a study, the quantity of goods to be transported in Germany will significantly increase again by 2030. And though electrification will also find its way into commercial vehicles, the focus in the foreseeable future is more on equipping light urban distribution vehicles and city buses with the new powertrain technologies. Conversely, the beginning of the next decade will still see the combustion engine playing a significant role in heavyduty, long-distance hauling trucks.
THIRTY TIMES AROUND THE EARTH AND NO WEAR AND TEAR
POWER CELL UNITS FROM MAHLE RELIABLY WITHSTAND ENORMOUS LOADS
"Besides reliability and durability, low fuel consumption plays an extremely crucial role."Vice President Sales Commercial Vehicles
RISING EXPECTATIONS FOR DIESEL ENGINES
This initial position already makes it clear that the demand for high-performance diesel engines for trucks will continue to rise over the coming years. However, the expectations for these units are also increasing, as Matthias Fix confirms: “For logistics companies, the total cost of ownership (TCO), or overall operating costs, is an extremely decisive factor. This is because they are under increasing pressure to reduce costs despite the rise in freight rates. Low fuel consumption thus plays a significant role in the bigger picture.” Trucks therefore not only need to be fuel-efficient, but they also need to run for as long as possible and, above all, without any problems. MAHLE has already been accompanying the development of trucks since the company’s foundation in 1920. Over the decades, the MAHLE technologies for diesel engine solutions have been constantly refined and optimized to meet the increasingly stringent emission standards and make the trucks “cleaner.” Modern trucks have little in common with the trucks of earlier days. Forty years ago, the fuel was injected with a mere 180 bar. Today, injection pressure amounts to 2,700 bar, with a much finer diesel distribution in the combustion chamber—with top precision and electronic operating map control for the optimum time of injection. The fuel thus burns much more efficiently at combustion chamber pressures of up to 250 bar.
TAKING STOCK AFTER 1.2 MILLION KILOMETERS
The so-called power cell units—consisting of pistons, pins, piston rings, and cylinder liners—need to reliably withstand this high cyclic pressure and the temperatures that occur during combustion: kilometer after kilometer, route after route, year after year. During the course of the field observation, MAHLE grappled with the question: how does a mileage of more than one million kilometers impact a power cell unit? This was the starting point of an exciting examination. In the spotlight: a white Volvo truck, which at first glance had obviously already experienced quite a lot on its countless journeys through Europe. The truck was borrowed from a dealership. “We were allowed to look inside the engine and in return the Volvo received an engine rebuild with new power cell units from MAHLE,” relates Dr. Andreas Pfeifer, Head of Development Engine Systems and Components. The MAHLE team then took a look at the unit that so interested them under the driver’s cab: a six-cylinder turbocharged diesel engine with a displacement of 12.8 liters and an output of 480 hp (353 kW). The Volvo has already travelled a long, long distance with this engine— more than 1.2 million kilometers in total, which corresponds to almost 30 times around the earth.
The quality of the components was quite apparent during the examination: “We measured the pistons and even we were somewhat surprised: after this long period of time, their tolerances were virtually indistinguishable from a new product.” The pistons weren’t the only parts that survived the prolonged stress totally unaffected. The other MAHLE components in the PCU also demonstrated their high quality and durability by showing no significant wear. “Our analysis has shown that we have developed components, which delivered what we promised the customer at the time: high quality and reliability,” reports the MAHLE truck developer with satisfaction.
SOLUTIONS FOR THE TRUCK ENGINES OF TOMORROW
The investigated piston comes from an engine that meets the Euro IV standard. The emissions limits for the current “Euro VI” are considerably stricter, among other things. Lower fuel consumption is also required in order to reduce the total operating costs. “The critical aspect of this approach today, is not only to implement individual measures for each component, but to ideally tune the complete system consisting of engine and peripherals,” stresses Dr. Andreas Pfeifer. Improvements to the engine mechanics can also off-load the oil circuit. “The optimization then takes place across the engine— especially at the functional interfaces. The overall efficiency of the powertrain derives even greater benefits: “Efficiency and thus fuel consumption can be improved by up to three percent in total.”
Here, it becomes clear: changes in the commercial vehicle are the sum of many innovative steps, which not only have a novel approach but also view the truck as a complete system. Matthias Fix and Dr. Andreas Pfeifer unanimously define the goal in this way: “We want to ensure that, in the future, truck engines run reliably for even longer, require less fuel, and are less harmful to the environment. We are well on track with our systemic approach.”