R8 e-tron (Germany, 2009)

The Audi R8 e-tron is a high-powered sports car which is powered only by electric energy. The concept car is fitted with four engines that provide a total power of 230 kW (313 hp). These engines can be individually actuated, in an entirely new developmental stage of the permanent four-wheel drive.

The concept counts with four asynchronous motors, two each on the front and rear axles, making it a quattro vehicle. The power is brought to the wheels through a single-staged transmission and short input shafts. It features a power output of 313 hp and torque of 4500 Nm, available from standstill. The R8 e-tron is able to accelerate from 0 to 100 km/h in just 4.8 seconds.

Thanks to the location of the large, fluid-cooled lithium-ion battery and the power electronics, behind the passenger compartment, the R8 e-tron has an optimal center of gravity and a load distribution of 42:58 between the front and rear axles, the same as the series production R8 with its 5.2 liter FSI. The power supply comes from a rechargeable lithium-ion battery, which consists of single cells connected in parallel and in series. The 550 kg (1212.54 lb) battery stores 53 KWh of energy, with the usable share amounting to 42.4 kWh. Audi wants the final version of the R8 e-tron to have a range of 250 km, when operated in the NEDC cycle.

To charge the battery on the R8 e-tron a household current with 230 volts is sufficient. In this case the full charging takes six to eight hours. However, with a high-voltage current the charging time can be reduced to about two and a half hours. The battery can also recharge during the braking and deceleration phases, when driving. The four electric motors are able to recover a considerable part of the energy.

Audi confirmed that its R8 e-tron concept will be produced and arrive to the roads in late 2012. The sports car will be produced at quattro GmbH in Neckarsulm.