Sep 30, 2009, 16:43 GMT
Frankfurt - One of the stars at the Frankfurt Motor Show (IAA) was the Audi e-tron with engineers demonstrating the challenges posed by building a super sports car on electric drive with an output of 230 kW/313 hp and a range of almost 250 kilometres.
Based on the existing R8 super sports car, the all-red concept appears almost monolithic. The front is dominated by the trapeze of the single-frame grille flanked by two large air intakes which are closed under normal driving conditions with flaps opening when additional cooling air is required, providing a maximum drag coefficient.
The cabin of the e-tron is shifted far forward toward the front axle, leaving room in front of the rear axle for the roughly 470 kilogram battery unit, the inverter and the power electronics. Placing the battery in front of the rear axle also ensures an optimal axle load distribution without compromising the compact overall design and interior space. The battery system is water-cooled for optimal performance and service life.
Four asynchronous motors with a total output of 230 kilowatts (313 hp) catapult the e-tron from zero to 100 km/h in 4.8 seconds. The torque flows selectively to the wheels based on the driving situation and the condition of the road surface. The top speed is limited to 200 km/h.
Lightweight construction materials based on Audi Space Frame (ASF) technology are used with all add-on parts such as the doors, covers, sidewalls and roof made of fibre-reinforced plastics. The combination of aluminium and carbon fibre-reinforced composite material guarantees rigidity coupled with low weight totalling 1,600 kilograms.
The interior design stands out with the near total elimination of switches and small components such as the ignition. The climate control unit is located to the right above the steering wheel. The display provides temperature and ventilation information. Drawing inspiration from a smartphone, the system is controlled by a touch-sensitive sliding control.
The energy storage unit is charged with household current (230 volts, 16 amperes) via a cable and a plug. The socket is behind a cover at the back of the car. With the battery fully discharged, the charging time is between 6 and 8 hours. A high voltage (400 volts, 63 amperes) reduces this to around 2.5 hours. Audi engineers are however working on a wireless solution to make charging more convenient.
Audi did not reveal when the car would be ready for volume production, admitting 'there is still a lot of work to do' with the greatest challenge posed by integrating the energy storage system and configuring all components for electric drive.
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