Audi has taken the wraps off a sophisticated plug-in hybrid prototype that combines a number of leading green car technologies all in a single platform.

Utilizing the shell of the luxurious A5 Coupe, Audi’s new A5 e-tron quattro prototype not only features a conventional power-split hybrid system but also a newer ‘through-the-road’ setup.

A through-the-road hybrid drivetrain is just like a regular hybrid but instead of combining the respective gas and electric powerplants on a single driveshaft, they are used individually on opposing axles.

In this fashion, a through-the-road hybrid offers all-wheel drive capability without the associated heavy weight of multiple driveshafts and gearsets typical of most all-wheel drive vehicles.

Not surprisingly, several major automakers are flocking to the technology, with Peugeot set to launch the world's first production version in its new 3008 HYbrid4 and Saab recently showing off a concept version in its new PhoeniX.

As for the new A5 e-tron quattro, it features a regular power-split hybrid setup on the front axle, consisting of a 211-horsepower 2.0-liter TFSI turbocharged gasoline engine, putting out 258 pound-feet of torque, matched to a lightweight four-speed automatic with a compact electric motor with 33 kilowatts (45 hp) on tap.

2011 Audi A5 e-tron quattro hybrid prototype

2011 Audi A5 e-tron quattro hybrid prototype

Forming the through-the-road portion of the hybrid drivetrain is a second electric motor rated at 60 kW (81 hp) and powering the rear axle.

Note that this motor is only used when additional acceleration is required or if sensors at the wheels detect a loss of traction.

Both electric motors can also be used to recover brake energy in order to top up the car’s lithium-ion battery pack. The batteries can also be charged by plugging the vehicle into a regular household power outlet.

Drive modes include purely gas power, a mix of gas and electric, or electric only. When fully charged, the A5 e-tron quattro prototype has an electric only driving range of 40 miles and top speed limited to 62 mph. If increased range or performance is needed, the driver need only keep his or her foot on the pedal and the internal combustion engine will kick in.

Here's the kicker--despite all of this extra technology, the A5 e-tron quattro prototype weighs about the same as a regular all-wheel drive A5 fitted with only the 2.0-liter TFSI engine. This was brought about by the increased use of lightweight aluminum and carbon fiber in place of conventional steel components.

As mentioned, the new A5 e-tron quattro is only a prototype but it shows the expanded direction Audi is taking for its next-generation of cars. We can’t wait for the production versions.



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