Mercedes-Benz aerodynamics: Emotion meets efficiency

Sep 5, 2013
In terms of wind resistance, noise level, open-top motoring comfort and anti-soiling measures, in other words in all aspects of aerodynamics, Mercedes-Benz models have held the top position in practically every vehicle segment for years now. Which just shows that exciting, sensual design and high aerodynamic efficiency are not contradictory concepts. With the new aeroacoustic wind tunnel at the development centre in Sindelfingen, which will be officially inaugurated on 5 September 2013, the company has once again placed itself at the forefront of aerodynamic testing. The new aeroacoustic wind tunnel is just one element in a comprehensive programme of investment in vehicle development being undertaken at the Sindelfingen site. It joins the driving simulator centre brought into operation three years ago as well as the climate tunnel before that. The new technology centre for vehicle safety is currently under construction.
For almost three decades, the aerodynamic specialists at Mercedes-Benz have been breaking one record after another. "Currently, models bearing the three-pointed star take the lead in almost all vehicle classes as far as aerodynamic performance is concerned", says Professor Dr Thomas Weber, responsible for Group Research and Mercedes-Benz Cars Development. The new S-Class, likewise, heads its segment in terms of aerodynamics and aeroacoustics.
At 0.24, the drag coefficient of the S-Class improves on that of its predecessor by a further two hundredths, so not only setting a new benchmark in the luxury segment, but making the S-Class the most aerodynamically efficient saloon overall. The new S 300 BlueTEC HYBRID has a Cd figure that is another hundredth better, at 0.23. Not least as the result of its extremely low wind resistance, it also achieves an extremely impressive consumption figure of just 4.4 l/100 km or 115 g CO2/km.
Furthermore, when it comes to compact models such as the new A-Class (2012, Cd=0.26), coupés such as the E-Class Coupé (2010, Cd=0.24), saloons such as the E-Class (2009, Cd=0.25), sports cars such as the SL (2012, Cd=0.27) and SUVs such as the M-Class (2011, Cd=0.32), vehicles in these segments have never before achieved such low Cd figures. In its BlueEFFICIENCY Edition guise, the new CLA's Cd figure of 0.22 and wind resistance area of 0.49 sq m even set a new world record.
"This good performance can be attributed to some highly sophisticated improvements to the vehicle as a whole, as well as to careful work on the details", explains Dr Teddy Woll, Head of Aerodynamics/Wind Tunnels. Emotion meets efficiency: the more aerodynamic a car is, the lower its consumption will be. Woll: "In the New European Driving Cycle (NEDC), improving the Cd figure by 0.01 already lowers CO2 emissions per km by one gram, by two grams as a function of mean on-the-road consumption, and at 150 km/h by a full five grams of CO2 per kilometre." Eliminating irritating wind turbulence, however, also brings benefits in terms of safety, comfort and the environment. Reduced lift improves road holding, while low wind noise spares the nerves of both passengers and passers-by. Models from Mercedes‑Benz also take the lead in almost all segments when it comes to aeroacoustics. The new S-Class, too, not only offers the lowest level of wind noise in its segment, but is also quieter than the previous world champion of wind noise, the Maybach, so making it the quietest car overall.
New aeroacoustics wind tunnel: measurements up to 265 km/h
With its "large wind tunnel" in Stuttgart-Untertürkheim – the first measurement was recorded precisely 70 years ago, on 5 February 1943 – Mercedes-Benz was the first automotive manufacturer to have its own wind tunnel. The new aeroacoustic wind tunnel at the development centre in Sindelfingen once again puts the company at the forefront of aerodynamic testing. The new wind tunnel, which will be officially inaugurated on 5 September 2013, follows the Göttingen design, whereby the air is redirected to the blower after the measuring section and then re-accelerated to 265 km/h. Before the air accelerated by the blower reaches the measuring section, via a nozzle system that encompasses 28 sq m, it must be straightened and smoothed to eliminate unwanted turbulence and eddies. This is done using rectifiers and sieves. Extensive noise insulation measures are integrated to allow use as an acoustic tunnel where interior and exterior wind noise can be measured for the relevant test vehicle. Even at 140 km/h the air flowing through the measuring section is therefore as quiet as a whisper.
The centrepiece of the 19-metre long measuring section in the wind tunnel is the roughly 90-tonne conveyor belt/balance system with turntable. The new wind tunnel has a 5-belt system to simulate the road. The conveyor belt/balance system is integrated into a turntable with a diameter of twelve metres, which means that the test vehicles can also be subjected to an angled flow of air in order to simulate cross-winds. The traversing system enables the engineers to position a variety of aerodynamic sensors and microphones around the test object with a high degree of precision.
Mercedes-Benz: world aerodynamics champion in every vehicle class (german version)
Mercedes-Benz: world aerodynamics champion in every vehicle class