When it comes to aerodynamics, the two new models dramatically outpace the competition. The A4 Avant has a drag coefficient value of 0.26, the value for the Sedan is cd 0.23. These extremely low figures are the result of complex fine-tuning and new solutions. The outer lines of the air inlets integrate additional openings – they guide some of the air stream over the wheel well, where it flows past wheels which have also been aerodynamically optimized. Details such as the exterior mirrors positioned on the door sills with their small integrated narrow stripes help enhance the aeroacoustics.
In every new car, the rear design plays a key part in automotive aerodynamics. On the new Audi A4 Avant, a roof edge spoiler with a strong downward slant makes sure that the air flow is smooth. On the Sedan, the shape of the trunk lid performs this function. Narrow trim on both sides of the back window are the finishing touch on the aerodynamic concept.
The underbody of the new mid-sized models also contributes to their aerodynamic lines. The underside of the engine compartment is sealed off from the road, and broad trim under the passenger cell and the luggage compartments protects the metal. The wishbones on the rear axle are specially enclosed, and small spoilers guide the air flow at multiple sites, including under the wheels and at the tank. In conjunction with the design of the tailgate, the aerodynamically optimized underbody keeps the lift of the rear axle low.
The A4 TDI ultra models* work with another kind of new aerodynamic technology: controllable cool-air inlet. This is a frame installed behind the radiator grille which houses two blinds that can be activated independently. They are closed as the car starts so that air resistance stays as low as possible, and when air is needed to cool the engine, first the lower and then the upper blind opens.
*The fuel consumption and CO2 emission figures of all models named above and available on the German market can be found in the list on the last page of this basic information.