Mass-produced lightweight construction is only really effective when all production and model development know-how comes together as early as possible. For this reason, input from production experts is required at the concept stage of a new model, and plays a key role in the development of powerful new alloys and materials. In recent years, Audi engineers have continually developed Space Frame technology. Today, the body is strengthened by organic-looking structures, not unlike a bionic framework: “These are reminiscent of the bones in the skeleton of a bird,” explains Timm, an expert in lightweight construction. Special computer programs help the engineers to find the ideal inner structure for each part – these should be as light as possible, yet still possess the required stability. They should also be deformable, making them safer in the event of an accident.
100 YEARS OF “VORSPRUNG DURCH TECHNIK”
A hundred years on, August Horch’s vision of building sporty, high-quality and technically innovative cars is as alive as ever. In 1899, Horch founded the “A. Horch & Cie.” automobile factory in Cologne, Germany. When he left in 1909 to form his own company in the Saxon town of Zwickau, he called it “Audi” – Latin for “hear” or “listen.” In the early 1930s, Audi, DKW, Horch and Wanderer came together to form “Auto Union.” Four interlocking rings became the trademark. In 1958, Daimler-Benz acquired Auto Union, which had relocated to Ingolstadt after the war. However, Audi’s star really began to rise again when it finally found a home in the Volkswagen Group in 1965 – with models such as the Audi Sport quattro, the Audi 100 and 80 series, the Audi A8 with Aluminium Space Frame and the Audi R8 going on to write automotive history. In 2009, Audi celebrated its centennial with over 50 special events. The central motto: “Vorsprung durch Technik” – across generations of automobiles.
LIGHTWEIGHT CONSTRUCTION EXPERTISE FROM NECKARSULM
A further milestone in lightweight evolution comes in the form of magnesium components, which are a third lighter than aluminium parts. This ultra-light metal was first used in the Audi R8. In the case of new models, magnesium is even used for certain engine components, for example the top of the oil sump and the camshaft housing cover. In the new Audi A8, the gearbox is mounted on a magnesium cross-member – previously the exclusive reserve of steel. Audi engineers are working intensively to make magnesium an affordable option for mid-range models as well. A number of components made of the ultra-light material can already be found in the current Audi A5 Cabriolet. “However, the material is just the first step,” says Peter Fromm, Head of Technical Development. His team is working on mass production processes, an area that throws up many different challenges. For example, aluminium and steel expand to different degrees when exposed to heat. This calls for new joining techniques such as “flow drill” screws, which are inserted by robots into the metal so fast that they melt, thus forming their own thread. Engineers are now looking for ways to series-produce fiber-reinforced plastic components like those so far used primarily in Formula One and aircraft construction. Audi has added a new section to its Lightweight Construction Center for this purpose. And those who know Peter Fromm and his colleagues would be the first to agree that this could well be the cradle of the next lightweight construction revolution.
LIGHTWEIGHT CONSTRUCTION THROUGH COMPOSITE DESIGN
The Audi A8’s aluminium frame weighs in at around 40 percent less than a conventional steel body.