Using computer modelling, on-the-road testing as well as during wind tunnel, Mercedes Benz has optimised the performance of the Actros that won the prestigious International Truck of the Year 2020 award
Late November 2019, Mercedes-Benz Actros won the prestigious International Truck of the Year (ITOY) award 2020. During the event, the jury also mentioned the progress the ITOY winner made in assistance and safety systems as well as in connectivity. The new Actros features Active Drive Assist, which enables semi-automated driving in all speed ranges, improved Active Brake Assist 5 emergency brake assistant, a fully networked multimedia cockpit as well as Predictive Powertrain Control intelligent cruise control and transmission management system. In addition, the company has worked diligently over the last decade to make the Actros more economical and efficient.
Mercedes Benz engineers have been optimising the fuel consumption of the Actros over the past few decades. Over the last 9 years itself, the company has been able to make the Actros more economical by 15 % for typical long-haul operations. Riding the Predictive Powertrain Control (PPC) cruise control and transmission control system as well as new rear axle ratios, the Actros has efficiently banked on its cab aerodynamic improvements to achieve savings up to three percent on motorways and up to five percent during inter-city operations.
According to the company, as much as one-third of the mechanical energy in a modern cab-over-engine truck is required to overcome air resistance during European long-distance operations. Mercedes-Benz has replaced the traditional rear-view mirrors with MirrorCam as well as introduced concave cab side deflectors on the cab that has contributed 1.5 % of fuel savings. The company intensively tested the Actros in the wind tunnel at its Untertürkheim plant in Germany, wherein the engineers simulated the flow conditions around the truck with the aim of optimising the Cd value for wind slip, thereby reducing fuel consumption. The company also optimised the MirrorCam aerodynamic design along with its position on both sides of the cab as it has been fixed to the roof frame in the new Actros.
Mercedes Benz has been capitalising on its wind tunnel at its Untertürkheim facility over the last eight decades and has been updated at regular intervals to increase product efficiency. In the test area, the vehicle is parked on a turntable with a diameter of 12m so that it can be exposed to the wind flow not only frontally, but also laterally at any desired angle. Currently, two DC motors, each with an output of 250 kW, set the nine-blade axial fan with its 8.5 metre diameter in motion, which can generate gusts of up to wind force 17. To do this, around 9,000 m3 of air are blown horizontally through the 125-metre long, ring-shaped channel. Integrated into the turntable in addition to a roller dynamometer is a six-component weighbridge which is used for the highly accurate determination of numerous forces, including the air force. The forces are transmitted to load cells via levers and rods and can thus be evaluated.
The wind tunnel at the Untertürkheim plant enables the developers to generate wind speeds of up to 250 kilometres per hour, which is followed by validation of aerodynamic measurements during on-the-road testing. Random spot checks were carried out, in parallel to computer-based flow calculations using computational fluid dynamics in order to confirm the aerodynamic improvement of conceptual components, said Michael Hilgers, Head of CAE Vehicle Functions in Commercial Vehicle Development at Mercedes-Benz. A major part of dust kicked up by the truck as well as vehicles in front often gets stuck on the vehicle. The engineering team at Mercedes Benz has also ensured eliminating dirt from the vehicle parts, such as windscreen, side windows as well as cameras in order to reduce fuel consumption using wind tunnel test and CFD analyses.