The Fully Electric Audi e-Tron

Audi got rave reviews when it unveiled its e-tron electric concept car at the Frankfurt Auto Show last year, but just three months later the company unveiled a second e-tron - this time at the Detroit auto show. The new e-tron is substancially different from the previous e-tron, with smaller dimensions, less overall weight, and a sexier look.

Powered by a huge 880-pound lithium ion battery, the e-Tron has 204 horsepower - launching the car from zero-to-60 mph in 5.1 seconds. The big battery also gives the car a range of 155 miles.

Audi made extensive use of aluminum and carbon fiber in building the car - based on the German carmaker's excellent R8 - and made the doors, roof and other body panels of fiber-reinforced plastic. Driver inputs are all space-age: the rearview mirrors have been replaced with closed-circuit television monitors, and the propulsion system is state-of-the-art electric. This car is truly a look into the future of the automobile, and is completely dedicated to showing off the automaker's prowess in the high-tech arena.

But for all its gee-whiz gadgetry, high-tech engineering and forward-thinking design, the most amazing thing about this car is that it's as close to a production model as a prototype gets. In fact, Audi says it will build 100 e-trons in 2012, with more to come if demand warrants. If Audi can deliver on this promise, it would be like your power company pledging to build lunch-box-size nuclear reactors that will power your house for pennies a month, then actually doing it within a couple of years.

The svelte carbon-fiber bodywork is very much show-car stuff. There is no "hood" for the "engine compartment," no trunk lid and no trunk. Those will all come in the production version, but for now the e-tron's facade is young and taut, free of cut-lines and styling blemishes.
Under all that sleekness hides the heart of this lean and mean-looking beauty: an electric motor at each wheel, a 100-cell lithium-ion battery pack and a water-cooled power-control unit. Computers from existing production Audis (with a software upgrade, of course) are used to shuttle electrical power among the two motors for the ultimate in acceleration technology. The automaker calls it "force vectoring," but by any name it allows easy control over mundane issues such as traction control in slippery weather, and unparalleled ability to vary power for the ultimate in stability control.

Furthermore, the two-motor drive allows equally flexible control during braking, or braking for stability control. And unlike conventional brakes, energy is recouped to the batteries rather than discharged as waste heat. That said, the e-tron is fitted with massive, 4-wheel discs strictly as show-circuit window dressing. Conventional brakes are still required, but they can be much smaller and lighter because the motors handle most deceleration chores. Additionally, the rear brakes are electronically actuated - "brake-by-wire." Audi says this ensures no residual drag when not braking.