Bugatti has pushed digital design of its latest 261mph (420kmh) Divo supercar to over 90 percent using virtual reality goggles.
The Bugatti design team under chief designer Achim Anscheidt has digitalised more than 90 percent of the creative model development process and shift the design process.
“I had always wanted to understand how technical things work – and optimize them if at all possible,” said Ahmet Daggün, Director of CAD and Visualization at Bugatti, which is a brand of Volkswagen. This includes the design development processes, as well as the technical components. Half of the design of the Bugatti Chiron was already produced digitally, and this share increased to 90 percent for the latest Divo hyper sports car that is just entering production.
“With the Divo, we proved for the first time that we could use the digital design process to develop a breathtaking shape into an extraordinary vehicle that is ready for the prototype stage within just a few months,” said Daggün. This would not have been possible within such a short timeframe with traditional 1:4 scale models in clay.
Around half the time and a quarter of the development cost can be saved by using the digital process. The significant improvement of VR data goggles, which now provide designers with a hyper-realistic view of virtual models, was crucial for the technological breakthrough.
“Today, we are the leading manufacturer to apply this form of development in such a systematic way, and not just in the hyper sports car segment,” said Stephan Winkelmann, President of Bugatti. “As the manufacturer of the world’s most outstanding vehicles, we are obligated to always develop new ideas, both in terms of technology and design.”
Everything starts with the draft from a creative individual such as Anscheidt. Design computer specialists then digitize this draft and virtually develop the shape on the screen. “We subsequently refine the curves, adapt surfaces and balance the interplay of light and shadow. We generate a VR presentation from the completed digital data record, which comes stunningly close to seeing the real thing,” said Daggün.
Using VR goggles with a high depth effect allows the designers to assess the vehicles, from all sides. Experts implement requested changes within one day – regardless of the country in which the decision-makers such as Bugatti President Stephan Winkelmann or Chief Designer Achim Anscheidt are currently located. With an analogue clay and paper process, this took up to two weeks.
Bugatti then produces a physical data control model from rigid foam as soon as an agreement has been reached on the digital model. Designers and developers analyse the proportions at a distance of between 30 to 40 meters to get a better impression of the shapes and proportions.
“A physical model you can touch is still important because Bugatti vehicles are always highly emotive and we really want to feel them,” said Anscheidt. Any requested changes are manually visualized by the designers for correction on the respective model and are incorporated in the digital model so that a show car or pre-series vehicle can be directly created from the final data record.
“Thanks to this digital process, we save a minimum of five months development time, while also increasing the number of adaptation loops and thus also the quality. Digital models also allow us to identify and smooth out even the smallest imperfections in advance. We therefore designed the Bugatti Divo in six months instead of one year,” he said.
All the engineers involved are also experts in computer-generated imagery (CGI) and image synthesis. It is extremely important to have an excellent visual understanding of 3D animations, vehicle volumes, shapes and defining contours. “These individuals are absolute specialists and without them, this process would not be possible,” said Anscheidt.
This includes the design of the air conditioning systems that have to handle high speed air flows as part of the design. The entire air conditioning system includes the cooling circuit for the interior, air flow, electrical system, electronics and the air conditioning unit as the system’s central control unit.
“Our vehicles travel very fast. In order for the air supply to work properly at maximum speed too, we need to ensure the ventilation and air conditioning are particularly well controlled,” said engineer Julia Lemke, and the air conditioning system changes the air flow at fast driving speeds. In conventional vehicles, air is forced into the interior at the lower end of the windscreen, but in a Bugatti this only happens up to about 250 km/h. From this point onwards, there is a switch to negative pressure with a sophisticated control system with an additional ram air flap and an optimised blower to ensure that air continues to enter the interior.
The streamlining of the design requires a flat windscreen with an inclination of just 21.5 degrees. This increases the surface area of the glass to 1.31 square metres that creates more solar heating, compared to a conventional compact car with a glass area of around 0.70 square metres and an angle of inclination of around 30 degrees.
The Divo has an air conditioning compressor with a cooling capacity of up to 10 kW and two air conditioning condensers, enough to cool an 80m2 apartment in Europe. Approximately 3 kg of coolant per minute can be compressed from a pressure of about 2 bar to a high pressure of up to 30 bar.
The compressor mounted on the engine is also exposed to very high ambient temperatures due to its proximity to the exhaust system, so this is cooled by another sophisticated system.
“At first glance, our air conditioning system appears to function like a conventional system. But it’s a real challenge to perfectly harmonise the highly complex system of a small-series hyper sports car so that it works impeccably even at maximum speed and engine load,” said Lemke.
Alongside the design of the vehicle systems, she conducts research and development on maximum cooling capacity as well as efficiency, system acoustics and draught reduction. This includes reducing and refining the refrigerant circuit so as to minimise the use of refrigerants and energy consumption.
“The deeper I get involved as an engineer, the more I admire what is achieved overall in the development of these vehicles,” she said. “The enormous power of the W16 engine and the incredible speed are unique – this is what makes this highly complex system different from the rest.”