A NEW KIND OF COMPETITION is gaining momentum in the automotive industry: who will build the lightest cars in the future? Efficient engines and solid technology alone will no longer be enough if car manufacturers are to convince customers of their innovative genius. Lightweight construction, especially using carbon-fibre materials, is regarded as a key technology for tomorrow’s mobility, say industry experts like German car expert Professor Ferdinand Dudenhöffer. The big German brands Audi, BMW, Daimler and VW are already working flat out to get their “extra light” cars ready for the market.
The strong trend towards lightweight materials is not restricted to the auto industry, however. The spectrum ranges from aerospace to machinery and plant engineering to renewable energies. In view of rising commodity and energy prices, “smart efficiency” is becoming an increasingly important guiding principle for industrial processes. The idea describes the intelligent and resource-efficient use of materials and energy – coupled with optimized production processes and cost-effective management. At the 2011 Hanover Fair in April, “smart efficiency” was the overarching theme accompanying the 13 leading international trade fairs of the world’s largest industrial exhibition. The fair showed how the automotive industry could save energy and resources by using lightweight materials, showcasing the example of lightweight components made of aluminium and magnesium.
Lightweight materials are in great demand among German car manufacturers, who want to further exploit the potential of mobility. BMW is emerging as a pioneer. In February 2011 the group launched a major marketing campaign to present its new electric cars made of lightweight CFRP (carbon fibre reinforced plastic). The first mass-produced models are scheduled to roll off the Leipzig assembly lines in 2013. Shortly afterwards, Daimler announced an alliance with the Japanese chemical company Toray. The joint plan is to mass produce CFRP car parts for the first time. Europe’s biggest carmaker wasn’t standing idly by as these developments gained momentum: VW bought a stake in SGL Carbon. This Wiesbaden-based company, which describes itself as the only carbon-fibre manufacturer in Europe, had already entered into a joint venture with BMW in 2009.
Model weight looks likely to have a huge influence on the market shares and brand images of Germany’s leading car manufacturers. Despite frequent initial claims that lightweight materials were too expensive for mass production, weighty facts have led to a change of mind. As a rule, the more a car weighs, the higher its fuel consumption and therefore the higher its emissions of climate-damaging carbon dioxide. Every kilogram less does not only save money at the fuel pump. It also improves the vehicle’s ecological footprint. But the real challenge arises in connection with electromobility, where weight counts much more than before. An electric car’s heavy batteries already limit its reach. Engineers are therefore developing the lightest possible chassis parts. They could be helped here by a material that originated in space research and up to now has been used mainly in motor sports: CFRP. This miracle material for the new lightweight era could replace traditional steel and aluminium in many areas. CFRP is just as strong and resilient as steel, but weighs less than half as much. According to car expert Ferdinand Dudenhöffer, BMW currently has a good head-start when it comes to lightweight construction using CFRP. The passenger compartment of the new BMW i3 electric car is made of CFRP.
The main criticism of carbon, however, is that, unlike aluminium, it cannot be recycled. It also has a negative overall energy balance: the higher cost and carbon footprint of a CFRP car is not offset even after high mileage, critics say. Even so, there is probably no alternative to CFRP in the long term, especially since modern car production technologies make it possible to process different materials in parallel. For example, Audi plans to cut 400 kilograms off the new version of its (over-two-tonne) Q7 SUV by using a combination of steel, aluminium, fibre materials and magnesium. At the end of the day, an intelligent mix of lightweight and conventional materials could decide the race for the lightest cars.////
