Electric sports car projects are gaining pace and Audi’s e-tron concept joined the potential industry queue at the 2009 Frankfurt Motor Show. With styling that echoes both the TT Coupe and R8, the concept has an ASF (Audi Spaceframe) aluminum alloy chassis and carbon fiber reinforced composite body (a combination that will be used in an Audi production vehicle). It is powered by four asynchronous electric motors, two at the front and two at the rear of the car, driving all wheels, making the concept a quattro. A sophisticated control system can provide torque vectoring to each wheel.
Total output is 230 kW with an extraordinary claimed torque figure of 4500 N·m (3320 lb·ft). Performance figures include 0-100 km/h (0-62 mph) in 4.8 s and 60-120 km/h (37-75 mph) in 4.1 s. Top speed is electronically limited to 200 km/h (124 mph).
Intelligent aerodynamics are incorporated in the design and include smart air intakes, opening as required by the car’s energy/thermal management system. The e-tron’s LED lighting system is similarly controlled, but to meet specific ambient conditions such as fog or rain.
The 42.4-kW·h water-cooled battery, which weighs about 470 kg (1036 lb) is, not surprisingly, lithium-ion (Audi will also use lithium-ion for the hybrid Q5). It gives the car a maximum range of almost 250 km (155 mi). Positioned just aft of the passenger cabin ahead of the rear axle together with the inverter and power electronics, it provides optimal front/rear weight distribution (42/58). Total recharging in 6-8 h is via a household cable and plug at 230 V and 16 A. A high-voltage charge of 400 V and 63 A would cut the time to 2.5 h. Also, Audi is developing a wireless charging system.
The front electric motors are positioned on the front axle with a cooling system ahead of them, while the rears are behind the back axle.
The car’s technology includes what Audi describes as an “innovative thermal management system” to look after the drive system, power electronics, and battery; it is said to be a crucial element in the e-tron’s ability to achieve its designated range. The e-tron also has car-to-x communication, which networks the concept’s electronics with surroundings and ambient conditions, such as information about traffic light cycle times and traffic flow. It could be used to compute an optimal driving (and energy consumption) strategy.
Audi stated at Frankfurt that, rather than create a concept based on a current model, its development engineers designed or specified almost all of its components based on the requirements of electric mobility to achieve effective systems integration.
Dimensions of the e-tron include a length of 4260 mm (167 in), height of 1230 mm (48 in), width of 1900 mm (75 in), and a wheelbase of 2600 mm (102 in). Vehicle mass is about 1600 kg (3530 lb). Suspension includes triangular double wishbones at the front and trapezoidal wishbones of forged aluminum at the rear.
The e-tron’s interior has a fold-out central display with integrated MMI functions that will presage a similar system in a production car—probably the next-generation A8. Flanking instruments are an analog speedometer and battery power consumption indicator. Audi has managed to exclude almost all knobs and switches from the interior; HVAC control is via a touch-sensitive sliding control similar to that of a smartphone. The concept has a heat pump instead of an electric heater.