Building them took two years but finally, Mercedes-Benz has started to operate its two new state-of-the-art climatic wind tunnels at its Sindelfingen site. The carmaker aimed to lessen the gap further between simulation and real-life testing. With this achievement, the carmaker has completed its next phase of expansion for its Mercedes-Benz Technology Centre. At the Sindelfingen site, there is a close network of research, development, design, planning and production teams that work together.
There is no other automaker that has something similar to this set-up. These days, cars develop first on the computer. Even before the first prototype is assembled, it has already gone through electronic simulations such as crash tests, aerodynamic studies, and suspension testing.
However, these simulations can never take the place of real-life tests or test rigs. One is a cold tunnel, with a temperature range of minus 40 to plus 40 degrees Celsius; while the other is a hot tunnel that has a temperature range of minus 10 to plus 60 degrees.
Each tunnel features an integrated twin-axle roller dynamometer that permits the car to go as fast as 265 km/h. These new climatic wind tunnels serve as the replacement for the current tunnels.
The cold tunnel had temperatures as low as minus 20 degrees Celsius and allows speeds of up to 64 km/h. Meanwhile, the hot tunnel has maximum limits of plus 40 degrees Celsius and a maximum speed of 100 km/h.
Mercedes-Benz has unveiled its state-of-the-art climatic wind tunnels that are used for testing its new cars. These tunnels are simply amazing as you can simulate any weather and environmental condition there is. That helps the German automaker know how its cars will perform no matter what the conditions are.
Testing could be done at any speed, whether mimicking full speeds or the slow speeds as if stuck in traffic. Driving at full and partial load, as well as uphill and downhill conditions, is also tested. Tests could also include a whole range of weather conditions, whether in extreme cold or extreme heat or driving through the dry air of a desert or in high humidity. Driving conditions under a heavy downpour, a soft drizzle, a brutal snowstorm, intense sunshine or overcast skies may also be tested.
Engineers at Mercedes-Benz can therefore test a wide range of functions and components using every road and weather condition known to them. The engineers, for instance, make sure that the engine cooling system would be able to withstand different stresses. They can also test whether the heating and air conditioning systems would be able to regulate the temperatures inside the cabin no matter what temperature it is outside and thereby ensuring passenger comfort at all times. Tests could also be conducted to see how the windshield wiper would work when it is dirty and exposed to any other conditions.
The engineers could also test other things inside the new wind tunnel, including how snow that has been displaced by a vehicle in front would affect the air intakes of the tested car. And most importantly, engineers can easily examine the vehicle electronics even in the most extreme weather and climate conditions, as well as dozens of other components.
And what’s more, the results seen in these tests are much more verifiable because the engineers are able to replicate the same conditions to check the validity of earlier tests.
Alternative drive systems benefit from the new climactic tunnels too.
These wind tunnels are fitted to also accommodate the use of hydrogen. This means that as early as now, engineers at the German automaker can easily test alternative drive systems that may be launched. For instance, fuel cell vehicles can also be tested here with the use of specialized sensors and effective air extraction systems.
Needless to say, complex engineering is necessary to come up with the capabilities of the new climatic wind tunnels. Two test rigs and their attached offices and control room take up around two thirds of the new 18-meter high building, with a total area of 70 meters by 60 meters. These test rigs each have insulated large windows that allow the engineers to control test conditions, regulate temperature, wind speed, humidity, and other settings. Data measurements are taken by sensors that then transmit the collected data to computers and displayed on several monitors in the control room.
There are powerful electric motors that move four precise rollers measuring two meters in diameter. This will help mimic the road surface in different conditions. The engineers can easily test all-wheel drive vehicles in this manner and with conditions that are faithful to real life ones. The climatic wind tunnels are also designed to accommodate all models created by Mercedes-Benz no matter how big or small these models are.
The test rig’s overall output is rated at 600 kW and is capable of reaching 780 kW for short testing periods. What this means is that you can test cars and vans up to 265 kilometers per hour. The dynamometer is able to test acceleration with a maximum tractive force of 12,000 Newtons per axle up to 20,000 Newtons in overload. That is just enough force to accelerate a 1,000 kilogram object to 72 kilometers per hour in just a second. It can test acceleration rates of up to 20 m/s2 or more than twice the acceleration caused by gravity in objects in free fall.
If you are testing braking mechanisms, the rollers can produce the same negative force. That helps the scientist mimic conditions like a long downhill ride in hot weather. There is more force working on the brakes in the tunnel than any condition possible in real life.
Then you also have cost cutting and energy saving technologies at work here. When testing a vehicle’s wheels, these wheels are rigged so that the wheels act like a generator while spinning using the power of the engine. While testing, the wheels also generate electricity that is fed into the grid for use.
Anywhere from a hurricane to a gentle breeze
The new test facilities enable engineers to test cars in conditions that closely simulate real life. The turbines of the tunnel can easily create airflow as necessary for the tests. It can generate gentle breeze to hurricane-like winds. In fact, in extreme cases, you can get winds of around 200 kilometers per hour. People facing wind speeds of at least 100 kilometers per hour are sure to be blown away unless they hold onto something stable.
Engineers can also regulate the wind speed. This is done using a speed-regulated fan and adjustable airflow for the air jets. The general rule is that the higher the speed you want to test, the smaller the cross-sectional area of the air jets should be. For instance, when testing passenger cars, you use a cross-section measuring eight square meters, while testing a Sprinter van means that the cross section will need to be raised to 12 sq. miles. Sports cars are often tested with a seven-square meter cross section.
Testers could also set relative humidity from about 5 to 95 percent. More than these, the hot and cold climatic wind tunnels differ in other details to be able to accommodate tests for a wide variety of conditions as required by the engineers.