Audi Unveils Smaller E-Tron Electric Supercar in Detroit

12 January, 2010 01:06:00

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Audi has unveiled a second electric supercar prototype at 2010 Detroit Auto Show, just a few months after the E-Tron debuted in Frankfurt and Los Angeles.

Audi says that “E-Tron” will be the name for a family of electric cars — hopefully to gain the same kind of resonance as “quattro” and “TDI.”

This Audi E-Tron is 3.93 meter (154.72 in) long and 1.78 meter (70.08 in) wide but just 1.22 meter (48.03 in) tall two-seater.

Coupled with the Detroit showcar Audi E-Tron’s low gross weight of around only 1,350 kilograms (2976.24 lb), high-torque power units driving the rear wheels guarantee commensurate road performance.

Two asynchronous electric motors with a total output of 150 kilowatts (204 hp) give the Detroit showcar Audi e-tron the performance of a genuine sports car. The concept car can accelerate from 0 to 100 km/h (0 – 62.14 mph) in 5.9 seconds if necessary, and goes from 60 to 120 km/h (37.28 – 74.56 mph) in 5.1 seconds. The torque is distributed selectively to the wheels based on the driving situation and the condition of the road surface, resulting in outstanding traction and handling.

The top speed is limited to 200 km/h (124.27 mph), as the amount of energy required by the electric motors increases disproportionately to speed. The range in the NECD combined cycle is approximately 250 kilometers (155.34 miles).

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. The charging time when the battery is empty is around 11 hours, but heavy current (400 volts, 32 amperes) cuts this to around just two hours.

The battery is charged not only when the car is stationary, but also when it is in motion. The keyword here is recuperation. This form of energy recovery and recharging of the battery is already available on many Audi production models. During braking, the alternator converts the kinetic energy into electrical energy, which it then feeds into the on-board electrical system.

The Detroit showcar Audi E-Tron in its further developed version goes one decisive step further into the future; an electro-mechanical brake system means the potential of electric motors for energy recovery can now be exploited. A hydraulic fixed-caliper brake is mounted on the front axle, with two novel, electrically actuated floating-caliper brakes mounted on the rear axle. These floating calipers are actuated not by any mechanical or hydraulic transfer elements, but rather by wire (“brake by wire”). In addition, this eliminates frictional losses due to residual slip when the brakes are not being applied.

By virtue of being isolated from the brake pedal, the Audi E-Tron’s electric motors can convert the entire deceleration energy into electric current and recover it. The electromechanical brake system is only activated if greater deceleration is required. These control actions are unnoticeable to the driver, who feels only a predictable and constant pedal feel as with a hydraulic brake system.

The Detroit showcar Audi E-Tron is able to distribute its electric motors’ high torque between the wheels entirely as required. Its “torque vectoring” is the key to a thrilling level of active precision and excellent traction. Thanks also to its low weight, short wheelbase and perfect weight distribution for dynamic handling, the Audi E-Tron has all the drivability of a go-kart – agile, good on bends and neutral right up to the very high handling limit.

As previously with the first E-Tron concept car shown in Frankfurt, Audi again bases all components in this electric vehicle on an integral concept with many revolutionary details: a heat pump as an efficient means of heating up and maintaining the interior temperature. The drive system, power electronics and battery have innovative thermal management – crucial for maintaining a high operating range coupled with outstanding interior comfort.

Check out the rest of our Detroit Auto Show coverage.

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