Design and development: Virtual and real – digital and real prototypes for the highest requirements

Nov 2, 2009
  • AMG with overall responsibility for design and development
  • Start of the design phase for the SLS AMG in 2006
  • Worldwide prototype testing since 2008
  • Endurance trials on the North Loop of the Nürburgring
  • More than 40 SLS AMG test cars in continuous operation
For the first time in its more than 40-year history, Mercedes-AMGGmbH has carried full responsibility for the design and development of a completely new car. This is not only solidly based on more than four decades of motor racing experience, but also on enormous know-how in the production of luxurious, high-performance cars plus networked development with selected Mercedes-Benz departments at the Mercedes Technology Center (MTC) in Sindelfingen.
Exhilarating driving dynamics and the day-to-day suitability typical of a Mercedes were central attributes in the specifications for the Mercedes-Benz SLS AMG. When realising and implementing their ambitious aims, the specialists at Mercedes-AMG in Affalterbach relied on the latest simulation programmes and sophisticated practical trials on every continent. The design and development of the new super sports car were concluded and approved at the end of 2006.
Digital prototype as the basis for the first physical prototypes
Before the first physical prototype could be built, the virtual prototypes had to be put through their paces. Accordingly the new Gullwing model was first brought to life on the computer screen as a digital prototype (DPT). Extensive research on this basis helped to establish how the objectives for the new super sports car could be achieved. Whether weight distribution, the installed position of the engine, centre of gravity, axle configuration, driving dynamics, aerodynamics, ergonomics, crash behaviour or the production process – the very latest simulation programmes allowed a realistic reflection of the vehicle and all its characteristics. The digital prototype was therefore a complete, virtual automobile.
The digital prototype was also a help in planning and building the first driveable technology carriers, i.e. cars equipped with the primary technical components such as the engine, brakes and axles - so-called "mulettos". Thanks to the virtual preparation work, these test vehicles in use since spring 2007 already had a very high level of maturity from the start. Ultra-modern measuring technology in these vehicles supplied valuable findings on e.g. the temperatures of the engine oil, coolant and brake discs - with an additional focus on lap times around the North Loop of the Nürburgring, for example, as well as measurable, precisely defined handling manoeuvres as a basis for comparing different axle kinematics or spring/damper variations.
The first disguised, physical prototypes of the SLS AMGhave been undergoing worldwide trials since summer 2008. Whether for the air conditioning, tyres, suspension, engine cooling, dynamic control systems or brakes, this standardised, highly sophisticated development and testing programme on test tracks and racing circuits, Alpine passes and specifically chosen public roads is aimed at achieving continuous further development and the identification of problem areas - and therefore the highest possible quality. More than 40 vehicles are in continuous operation for these tests.
In addition to these tests, individual components such as the engine, powertrain, transmission, axles and brakes, as well as the complete body structure, are tested to their limits on test rigs.
"Accelerated" endurance testing under the toughest of conditions
The extensive programme of vehicle development is supplemented by an endurance test which simulates an entire vehicle lifetime under the toughest of conditions in a relatively short time. The aim is to ensure a high degree of maturity before vehicle production can being at the Mercedes-Benz plant in Sindelfingen.
The endurance testing at a glance:
Long-term testing on a variety of different roads:
· all the components and systems are tested together in everyday operation. Loaded up to their permitted gross vehicle weight, the test cars are put through a precisely defined test programme on country roads, on motorways and in city traffic.
Endurance testing on heathland:
  • in this case, the developers focus on the durability of the chassis and suspension components, the entire bodyshell and the integral subframe on which the front axle, steering and engine are mounted. The test cars are loaded up to their permitted gross vehicle weight.
"Accelerated" endurance testing:
  • testing of the entire vehicle, focussing on the powertrain, chassis and suspension. Special features of the AMGprogramme include 10,000 kilometres on the Nürburgring's North Loopand 10,000 kilometres in city traffic.
Full-load endurance testing:
  • extreme acceleration and braking manoeuvres with a high proportion of full-load operation, making extreme demands on the cooling, fuel-delivery and braking systems.
World endurance testing:
  • testing of the entire vehicle, focussing on the powertrain and suspension Body
Long-term corrosion testing:
  • corrosion testing of the entire vehicle simulates the toughest dynamic and climatic environmental influences.
Final board approval:
  • all-inclusive verification of the degree of development and production maturity.
When development is concluded in January 2010, around 40 test cars will have absolved a distance of approx. 1.25 million test kilometres. The final aim is
"overall vehicle acceptance" – the long-awaited "Job No. 1", i.e. production of the first Mercedes-Benz SLS AMG cars for delivery to customers, can commence.