- The Aluminum and Lightweight Design Center turns 15
- Lower weight plays key role in all Audi models
- Intelligently combining lightweight materials is the future
Intelligent lightweight design has been one of the Audi brand’s core areas of expertise for years. Erected in 1994, the Neckarsulm site’s Aluminum and Lightweight Design Center decisively drives forward advances regarding the use of, and joining techniques for, lightweight materials.
Audi bucked the trend toward ever-heavier vehicles with its trailblazing lightweight aluminum technology: ASF (Audi Space Frame). ASF technology has already found its way into six Audi models: the first- and second-generation Audi A8, the Audi A2, the latest TT and TT Roadster, and the high-performance Audi R8 sports car. No other manufacturer in the world produces such a variety and quantity of aluminum bodies.
Neckarsulm’s Aluminum and Lightweight Design Center creates Audi’s ASF body concepts. Since the Center was founded in 1994, it has housed the collective expertise of the Development, Production Planning and Quality Assurance divisions. This facility has notched up a triple-digit number of patents. In 2008, the European Patent Office honored the Center’s achievements with the European Inventor of the Year award.
Audi is pulling out all the stops to make its vehicles even lighter, in turn enhancing their efficiency and rendering them more fuel-efficient. ‘Considerably reducing the weight of our vehicles is pivotal to our efficiency strategy. In this regard, Audi has the most experience and a wealth of innovative ideas. There is tremendous potential for years to come – particularly if we cleverly mix aluminum with revolutionary materials and new structural designs,’ says Michael Dick, Member of the Board of Management for Technical Development at AUDI AG.
The Aluminum and Lightweight Design Center seeks to further consolidate Audi’s technological edge by applying its know-how, step by step, to the entire model portfolio. The focus is on key materials such as aluminum, high-strength steels, and – in some cases – magnesium.
The head of the Aluminum and Lightweight Design Center, Heinrich Timm, is already looking ahead: ‘We must gear up for the next generation of lightweight construction – namely, fiber-reinforced plastics. The flexibility inherent to combining high-strength materials with a resin matrix makes it possible to design components perfectly suited to withstand loading. This design leeway is a large step toward lightweight perfection: we need to use the material only in those places necessitated by a given product.’
Mr. Timm added that the challenge lies in not only optimizing the design of components, but also economically manufacturing lightweight components for series production. At the Aluminum and Lightweight Design Center, 150 employees as well as quite a few doctoral and graduate-degree students are working hard on tomorrow’s innovations.
A look back at 15 years of the Aluminum and Lightweight Design Center
A pioneer in lightweight design
AUDI AG began focusing on lightweight design/construction quite some time ago. In the early 1980s, the Audi Space Frame (ASF) was born: a monocoque body, consisting of extruded aluminum sections and pressure castings.
Aluminum sheets are rigidly incorporated into the frame for enhanced load bearing. Depending on their respective functions, ASF components vary widely in shape and cross section. Like bones in a human skeleton, they pair ideal functionality with the lowest possible weight.
The advent of the ASF body necessitated a radical re-thinking of construction techniques. Specialists in Neckarsulm thus improved existing light alloys and process techniques. In addition to welding and adhesive bonding, punch riveting became a joining technique in automotive manufacturing.
Founding of the Aluminum Center
When series production of the Audi A8 began in 1994, its all-aluminum body constituted nothing less than an automotive revolution. That same year, Audi displayed remarkable foresight by housing the collective technical expertise of various departments under a single roof in Neckarsulm’s Aluminum Center, as it was known at that time. Engineers, materials experts, physicists and other specialists have been researching automotive lightness here ever since.
The aluminum body enters volume production
After the Audi A8, the first volume-production model featuring ASF technology arrived in 1999: the A2. More than 176,000 units were built in Neckarsulm. Among them were 6,450 units of the pioneering Audi A2 1.2 TDI, boasting average fuel efficiency of just 2.99 liters per 100 km (78.67 miles per U.S. gallon). That corresponded to CO2 emissions of 78 g/km (125.53 g/mile). The bodies of the TT Coupé and the Audi R8 as well as the TT Roadster’s hybrid steel/aluminum structure were developed at the Neckarsulm site. The Lamborghini Gallardo and the Gallardo Spyder also trace their roots to the Aluminum and Lightweight Design Center.
In 2007, Audi applied the ASF principle in a hybrid manner for the first time, to the TT’s body. The front end is made of aluminum, which comprises 69 percent of the bodyshell’s weight. There are fully galvanized steel components at the rear of the floor assembly; the doors and the trunk lid are also steel. This results in optimum axle-load distribution and, consequently, dynamic handling.
The Audi TT consequently sets benchmarks for fuel efficiency, as well. The 2.0 TDI quattro sips a mere 5.3 liters per 100 km (44.38 miles per U.S. gallon) and emits 139 grams of CO2 per kilometer (223.70 grams per mile). These are sensational figures for an all-wheel-drive sports car with an output of 125 kW (170 bhp).
Versatile lightweight design concepts
Neckarsulm’s Development Center broadened its horizon beyond aluminum long ago. High-strength steels, tailored blanks, fiber-reinforced plastics and magnesium are increasingly popular materials at Audi. The facility was therefore renamed Aluminum and Lightweight Design Center in 2004. ‘Although aluminum remains the principal material for lightweight construction, we continue to vigorously assess opportunities presented by other materials,’ elucidated Mr. Timm, head of the Center.
‘We strive to maximize the potential of materials for lightweight vehicles and to make use of the right materials in the right places. After all, Audi’s commitment to lightweight design regarding body manufacturing dramatically enhances fuel efficiency and consequently reduces CO2 emissions considerably – without any sacrifices in comfort, performance or safety. Reducing a vehicle’s weight by 100 kilograms (220.46 pounds) equates to fuel savings of 0.3 to 0.45 liters of fuel per 100 kilometers and about 9 to 12 grams fewer CO2 emissions per kilometer (14.16 to 19.31 grams per mile),’ added Mr. Timm.
Innovative high-performance technology
The high-performance Audi R8 sports car’s body concept epitomizes Audi’s vast range of technologies – the R8 even reflects aerospace-engineering expertise.
The body and its roof are made of aluminum; the front fenders and the sills’ trim are plastic. The rear frame consists of magnesium, the hood of composite materials and the sideblades of carbon-fiber reinforced plastic (optionally available).
Blazing trails in joining techniques
The Audi TT excels in handling and fuel-efficiency due to its hybrid ASF body, the rear section of which consists largely of aluminum but also some steel. A key contribution to this success is made by the techniques utilized to join these different materials.
Joints between aluminum and steel panels are executed primarily by means of punch riveting, clinching and adhesive bonding; adhesives function as a protective layer to prevent contact corrosion. The newly developed self-tapping screws are yet another joining innovation. Inserted at high speeds by robots, self-tapping screws first generate enough friction to melt open an aluminum component’s surface before penetrating the material to form a rigid connection. Another innovative concept appearing on the TT is the aluminum zero-gap joint, achieved by laser welding, between the roof and the side section.
‘Thanks to our years of experience with laser technology, we’ve been able to implement another innovation: using lasers to clean the connecting components,’ explains Center head Mr. Timm. ‘So we don’t have to go to the trouble of washing the components separately.’
Audi Space Frame technology wins one award after another
The Vorsprung durch Technik made possible by Neckarsulm’s Aluminum and Lightweight Design Center is a success story not only for car buyers, but also among automotive specialists. In 1997, the Technical University of Vienna presented the Ferdinand Porsche Award to Albrecht Reimold (now plant manager at Audi’s Neckarsulm site) and Heinrich Timm (now head of the Aluminum and Lightweight Design Center). They were the key people behind the development and production of the Audi Space Frame. In 2006, Automotive Circle International honored Audi with the Euro Car Body Award for the body concept of the TT. The same award went to the brand with the four rings in 2003 for the A8’s ASF body and in 2008 for the Q5’s lightweight steel body, which also features a wealth of innovative solutions.
Winning the European Inventor of the Year 2008 award was yet another milestone for Heinrich Timm and his staff. By late March, Audi had produced more than 552,000 – and Lamborghini 8,785 – vehicles with Audi Space Frame bodies. Suffice to say, engineers in Neckarsulm are working intensively on honing their expertise. ‘Our next A8 with an Audi Space Frame body will also boast several revolutionary technological advances,’ asserts Mr. Timm.
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