GREEN: First Drive: Audi E-Tron

From the December, 2009 issue of Automobile Magazine
By Georg Kacher
 The three volume German premium brands are about to introduce electric mobility from the top down – in new models like the BMW Vision EfficientDynamics, the electric Mercedes-Benz SLS AMG, and the Audi E-tron. We got an early turn in the E-tron, which aims at the niche currently owned by the Tesla Roadster.

Although it shares elements of its aluminum architecture with the R8, the E-tron is smaller, almost as short as an A3. Despite the generous wheelbase (102 inches), the cabin isn’t particularly spacious. The towering battery stack behind the rear firewall takes up even more space than the R8’s V-10 engine, transaxle, and fuel tank combined. Wrapped in liquid-cooled safety foil, the lithium-ion cells provide an energy capacity of 53 kWh, an exact match to the Tesla. To extend battery life, only 80 percent of that capacity is used. The batteries power four electric motors, rated at a total of 313 hp. The whopping maximum torque of 3319 lb-ft needs to be scaled back drastically so that full acceleration doesn’t peel the tread off the tires. “The biggest challenge is of course to synchronize the four motors,” says Thomas Kräuter, technical project leader for concept cars. “Since each wheel can be accelerated and decelerated individually, this is no mean feat.”

Time to put the electric showpiece to the test. Getting in is a challenge not only because of the concealed door handles but also due to the narrow door aperture and the restricted adjustment of the space-age bucket seat. The airy cockpit has a jet-fighter touch, with hard-to-decipher LED monitors instead of rearview mirrors; a dished, flat-bottom steering wheel; and various iPhone-style touch pads instead of push buttons. Hit the start button, and the gear lever rises from its flush sleeping position like the head of an angry cobra. I select D, but nothing happens. To save energy, the E-tron doesn’t crawl, so you don’t have to hold the car with the brake. At the first stab of the accelerator, the Audi takes off like a noiseless red arrow, but the quoted 0-to-62-mph time of 4.8 seconds is at this stage strictly theoretical, since the concept car weighs some 1300 pounds more than the target, and it’s muzzled by a speed limiter. In finished form, the E-tron will accelerate with no holds barred from 0 to 85 mph, at which point the system starts to ease off because of the rapidly increasing aerodynamic drag and rolling resistance. The top speed will be capped at 125 mph.

Driving an electric vehicle, you gaze at alien instruments, such as the neon-green power-reserve meter and the equally prominent range indicator. You hear unfamiliar sounds, like the gushing coolant flow that keeps the batteries healthy, the distant hum of the heat pump that also serves as the air-conditioning, the subdued whine of the regenerative brakes, and the much more intense mix of wind and road noise. What one doesn’t notice at relatively low speeds are the E-tron’s 70 percent rear-biased torque split, its 42/58 percent front/rear weight distribution, the torque vectoring that combats excessive understeer and oversteer, or the qualities of the suspension, which uses control arms in the front and rear. The carbon-ceramic disc brakes are squeezed by hydraulically operated calipers up front; the rear ones are electrically activated. The advantages of this arrangement are lower friction losses, lighter weight, and more efficient energy regeneration.

Feather-footed drivers can hope for a range of 155 miles between charges, but if you storm up a mountain flat-out, the low-power warning light will likely come on after only sixty miles. At the conclusion of our two hours of driving and maneuvering, the charge meter still read 40 percent full. With a 220-volt household current, a recharge can take up to eight hours. Tapping a 400-volt network drops that down to two and a half hours.

The E-tron will be built alongside the R8 and the Lamborghini Gallardo starting in 2011. The first year, Audi plans to build 100 units, most of which will be leased to customers. For 2012, the goal is 1000 vehicles for lease and sale. Of course, there are still many questions, typical of electric cars. How will the batteries cope with extreme temperatures, dust, and moisture? What effect will the number, sequence, and duration of charge cycles have? How do owners access and replace subpar batteries? How often will software updates be required? Will enough customers be willing to fork out at least $200,000 for what in essence is an experimental vehicle?

“The age of electric mobility has only just begun,” says Kräuter. “Audi wants to be a force to be reckoned with in this segment. Of course, there will be setbacks. But setbacks have always been part of the pioneer’s fate.”

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