2012 Audi A6 and TT RS. Click image to enlarge
Manufacturer’s web site
Article and photos by Paul Williams
Audi’s lightweight design philosophy
Neckarsulm, Germany – When Audi introduced its aluminum-bodied A8 luxury sedan in 1994, critics suggested that the future of such a vehicle was doubtful because it would be too expensive to produce, too difficult to repair and consequently too exotic for volume production.
After nearly 20-years, the company still builds its “Audi Space Frame” (ASF) aluminum A8 sedans, and has added the R8 high performance sports car with ASF, along with the TT, which has a hybrid aluminum and steel body. In addition, the A7 Sportback and new A6 sedan have steel bodies but feature a high percentage of aluminum in their construction. Indeed, Audi has become a leader in the use of aluminum and its application in the construction of automobiles.
But in a time of increased environmental awareness and climbing fuel prices, it’s interesting to note that nearly all consumer vehicles have become heavier — and consequently less efficient — over the past decades. It’s what Audi refers to as the “spiral of weight.”
Weight has been added due to more stringent safety requirements, more complex components, more luxury items and occupant conveniences, bigger wheels and tires… the list goes on. However, Audi has committed to each new model being lighter than the one it replaces – hence the need for a dedicated facility to develop lightweight technologies. At Audi’s Lightweight Design Centre in Neckarsulm, the mantra is, “every gram counts,” as work proceeds to reduce weight in all areas of vehicle manufacture, from wiring, to brakes; from speakers to body panels.
Audi TT structure (top) and TTS. Click image to enlarge
Aluminum – 40 per cent lighter than steel — is a key material in Audi’s philosophy of light weight being the answer to issues of fuel efficiency and sustainability. Light weight also impacts vehicle dynamics, as less energy is required to accelerate, turn and stop a vehicle that has less mass to manage.
Work is also proceeding at Neckarsulm toward a new generation of vehicle bodies that will be made from a combination of steel, aluminum and fibre reinforced plastics — the so-called Multi Material Space Frame — that will be better suited for volume production.
In the meantime, the Audi A8, A6 and TT are the lightest vehicles in their respective segments, and the new Q7 SUV will weigh 400 kilograms less than the outgoing model.
The difference when driving a lighter vehicle was demonstrated at Neckarsulm by comparing the outgoing Audi A6 with the new model in back-to-back road testing. As mentioned above, the new A6 (we drove 3.0L TDI examples, unavailable in Canada) weighs 80 kg less than its predecessor, and on the winding roads surrounding Neckarsulm, the new model felt more agile and responsive.
The new A6 also featured auto-stop technology, widely used in Europe, and also found in North America in hybrid vehicles. Look for auto-stop – where the engine shuts off at stoplights to save fuel — to be introduced to non-hybrid vehicles here in the coming years.