The better the aerodynamics of an electric car, the longer it will go With a coefficient of drag of 0.28 , the prototype Audi e-tron achieves top score in the SUV models. This value is an important factor in reaching a mileage of more than 400 kilometer in WLTP cycle. Virtual exterior mirrors are one of the hallmarks of the aerodynamic concept of this all-electric premium-class car . The script continuous tests in the aerodynamic tunnel
In front of the low-noise rotor, whose blades have a diameter of five meters, the prototype Audi e-tron has faded into the eye of the hurricane. At the aero-acoustic test bench at Ingolstadt's aerodynamic center, the quietest air tunnel in the world, Audi engineers optimize air resistance and generated noises in extreme conditions. Both parameters are essential for vehicle efficiency and comfort. Powered by a power plant with a power of 2.6 megawatts, the fan generates airflows up to 300 km /. In these conditions, the Audi e-tron prototype passes tests over 1,000 hours.
The result of this is to achieve a coefficient of flow of 0.28. The direct benefit to customers is the significant increase in the mileage, reaching over 400 kilometers, calculated on the WLTP cycle. Every hundredth of a drop in the drag coefficient increases the five-kilometer range in day-to-day driving conditions.
Air resistance an important factor when traveling over long distances
On long trips where the prototype Audi e-tron feels at home and in a perfect way, air resistance is a key factor in efficiency - significantly more important than rolling resistance and inertia. To overcome air resistance, the vehicle consumes extra energy. That's why good aerodynamics is extremely important. In the conditions of urban traffic, other factors are of paramount importance. There the electric car can recover a significant part of the energy used with braking regeneration, thus reducing the weight of the mass.
To achieve the 0.28 drag coefficient, Audi engineers apply a wide range of aerodynamic measures across all body parts. Some of these solutions are seen at a glance while others perform their tasks remaining hidden. Thanks to them, the drag coefficient of the prototype Audi e-tron is approximately 0.07 lower than that of a comparable conventional-propelled vehicle. In a typical user profile, these design solutions help increase the range by about 35 kilometers per battery charge per WLTP measurement cycle.
Intelligent solutions virtual exterior mirrors and dents of the underbody structure
Exterior Mirrors Offered as additional equipment will make their world premiere in the Audi e-tron series version. They are considerably narrower than the standard exterior mirrors, reduce the width of the car by 15 centimeters, and thanks to their optimized shape, they not only reduce the air resistance but also significantly reduce the noise. Each of their flat hulls integrates a small camera. The latter images appear on OLED displays located in the transition between the dashboard and the door. Virtual exterior mirrors can be adapted to different road situations, thus improving safety. There are three types of imaging in the MMI system: highway, turn and parking.
Another important factor is the standard adaptive chassis - air suspension with variable damping settings. At speeds above 120 km / h, it lowers the body position by up to 26 millimeters below the normal, thus further reducing air resistance. The substructure of the electric SUV model is completely covered by panels on the front and rear. Beneath the passenger cage, an aluminum plate protects the high-voltage battery from damage from sources below it like stones or unevenness. The areas of the mounting points of the bolts with which it engages are similar to the recesses of the golf balls. This solution helps for better airflow compared to the fully flat surface.
The controllable cooling chute behind the singleframe with two electrically opening louvers also helps to reduce the air resistance. When closed, the air in this zone moves, practically, without vortexing. When the drive components require cooling or the air conditioning condensing element requires ventilation, the upper rolling element of the louvers and then the lower one is opened. When the hydraulically actuated wheel brakes are loaded and heated, a two-channel controlled air gap is also detected in the front wheel arches to provide a cooling flow.
Side air holes at the front of the Audi e-tron prototype include additional channels visible from the outside. They take the airflow away from the aerodynamically optimized 19-inch wheels. The design of the latter is flatter than that of conventional wheels. 255/55 tires are distinguished by their ultra-low rolling resistance. Even the side parts of the car have an aerodynamic role - for example, the captions are reduced instead of convex.