Audi e-tron: The aerodynamics

Ingolstadt, Germany, 30. May 2018

The first electric model from Audi, the e-tron, comes the end of 2018 on the market. With 4.90 meters in length, the car belongs undoubtedly to the large SUVs à la the BMW X5 or the Mercedes GLE. Can handle a large (and heavy) car at all efficient with electrical energy? Yes, says Audi, is because less weight is as the aerodynamics of a role.

Small frontal area and good drag coefficient

Interestingly, referred to the Audi, the long-haul than the area of the e-tron. Long-distance one is allowed to translate with the highway, and that means high speed. Here, however, the aerodynamics plays the main role: at 130 km/h a car will have to spend three-quarters of its drive energy to overcome the air resistance. Two values are crucial: the frontal area A in square meters, and a form factor – the much-quoted cW-value. Both are the e-tron effective: Audi is the air drag area (CD x A) with 2.65 times the 0.28 is equal to of 0.74 square meters. That is a favorable aerodynamics, in comparison with the BMW X5 clearly, the 2,84 times 0,31 equal to 0.88 square feet to significantly higher values. Since the width of 1.94 meters is almost identical, the smaller frontal area of the e-tron is probably due to the lower height of 1.62 meters (X5: 1.76 meters).

For the first time, cameras mirror instead of the outside

But also, the cW-value of 0.28 is significantly lower than that of the X5. According to the Motto: small livestock manure also makes fine-tuned by the engineers at the various Places. Every action brings a couple of cW points to the Saving, where a point equals a thousandth of the cW-value. Five cW points less (i.e., a 0.05-square-lower cW-value) caused by the specially shaped side mirrors of the e-tron. Again five points you'd save if you ordered the "virtual" mirror. Here for the first time, built a series of cars, cameras instead of mirrors.

Disguised Under The Ground

With a Alu-plate, full-surface underbody panels brings an additional 17 cW-points. Again 15 cW-points of the controllable cooling air inlet (SKE) saves: Between the Grill and the coolers, there are two blinds that can be opened by small electric motors and closed. Between 48 and 160 km/h they are closed in the rule, to improve the flow of air. If cooling air is required for the drive components or the condenser of the air conditioning, you will be re-opened. Also, the condition of the front disc brakes is taken into account: do you Need cooling, the SKE special cooling channels.

Even the tyre label helps

Wheel arches and wheels are typically for one-third of the air resistance is responsible. To avoid air turbulence, the e-tron so-called Air-Curtain Vents that direct the air to the outside of the front wheels over. This brings a further five cW-points. Three points again Savings resulting from the optimized 19-inch wheels. Even the sides of the tyre are aerodynamically designed the lettering are negative instead of sublime. Another aerodynamic factor is the standard air suspension, which lowers the body depending on the pace. Result: proud 19 cW-points compared to a steel spring suspension.

35 km more range

Overall, the Audi e-tron saves almost 70 cW-points, so cut to about 0.07 square meters smaller air resistance than without the fine. That's a lot. Because according to the Audi in terms of cW makes a point of half a Kilometer more range. According to Adam Riese 35 kilometers. About nine percent of the total range, which is over 400 kilometers in the WLTP cycle. More impressive, however, is: to achieve the gain in Range due to weight reduction, you would have to save the engineers more than half a ton.(sl)