Finding a practical, safe alternative to conventional mirrors to achieve effective rear vision has been an automotive industry challenge for decades. Now, Audi has revealed that it has developed a rearview system for its R18 LMP racecar applying digital technology that may eventually prove to be a viable solution for road cars. It’s first application in a closed cockpit LMP sports prototype will be the Le Mans 24-hour race on June 16-17.
Using an AMOLED (active matrix organic light-emitting diode) system, it could replace not only the interior mirror to provide a wide-angle view but possibly also the exterior mirrors, which in recent years have become larger and more complex, adding cost, increasing aerodynamic drag, and causing physical obstructions.
The transfer of technology from racecars to road cars is often a difficult and at times wholly impractical course. However, Audi technology spokesman David Ingram said: “The company is constantly seeking new channels through which the technology that proves itself over thousands of race miles in its competition cars can be transferred to the road, and this could prove to be another of these opportunities for highly advantageous cross-pollination.
“The consistent quality and clarity of the image delivered by this system in all weathers, even at speeds a road car is unlikely to touch, combined with its ability to eliminate blind spots and minimize glare, make it a wholly viable proposition for road-going applications.”
The need for an entirely new and efficient rear vision system has been apparent for some time. But difficulties have included the use of cameras that would function in both very high and low ambient light conditions, on wet and muddy roads, and that could sustain minor damage but continue to function efficiently.
Motorsport requirements drove development of the new system to help reduce driver workload, explained Head of Audi Motorsport, Dr. Wolfgang Ullrich. He states that as well as the physical and mental strain in endurance racing, life for the driver of what he calls a “quick racer” compared with a touring car (sedan/coupe) is made more difficult by an extremely low, central seating position like that of the R18. And due to the concept and structure of the monocoque plus the configuration of the mid-engine, it has no rear window.
“In the past, our drivers had to rely on the outside mirrors when looking rearward,” explained Ullrich. “Yet the rear end and the rear wings plus the vibrations that occur at very high speeds significantly limit the field of vision of these mirrors.”
So Audi set about finding a solution that, thanks to the application of advanced technology, produces an “amazing effect,” he said: “The digital rearview mirror provides the rearward view on an AMOLED display with results that are better than any conventional mirror.”
A lightweight camera with dimensions of “just a few millimeters” is positioned behind the antennas on the roof of the Audi R18. It captures the view at the rear on film and transmits this to the cockpit as digitized data. This is viewed by the driver on a screen that is positioned where a regular interior mirror would be fixed at the top of the windshield.
“This gives us a whole host of benefits,” said Ullrich. “The operation of the mirror is weather-neutral. By contrast, when using outside mirrors in rainy weather, heavy spray severely impairs the driver's field of vision. For the new digital mirror, we worked out various day and night driving modes. Even when another car on the track approaches from the rear with high-beam headlights, the image is superb and not just a glaring light spot.”
To achieve these results, Audi specialists applied the latest-generation diode technology. Instead of conventional LEDs, the AMOLED display was developed. “Its name has been derived from organic semiconductors; their major advantage is that AMOLED screens can show multicolored images and offer better resolution thanks to particularly small pixels with diameters of around 0.1 mm,” Ullrich explained. “Outstanding image quality and short response times are further positive properties. Even at 330 km/h, we’re achieving a totally fluid image flow in real-time transmission.”
Because the new types of screens are freely programmable, Audi is able to display other data, too. This includes the gear that is currently engaged and the slip level of the tires. The system also includes specific warning lights.
“I'm pleased to see that we've managed to make another contribution to active safety through this technology,” Ullrich said. “We've previously achieved major effects not only with basic concepts but also through detailed innovations.”
He describes the digital mirror project as an example of the “close meshing” of volume production and motorsport: “With regard to the screen and the programming, we greatly benefited from the work at Audi AG’s Technical Development (TE). They helped us move forward both with components and knowledge.”
During the trial stage of the system, Audi race drivers used an application that originated with production-car engineers and specialists. The system was initially installed in an Audi R8 and tested on public roads by the company’s race drivers, Marcel Fässler and Marco Bonanomi, and subsequently installed for track car use. At present, Audi has not made any claims for the AMOLED system as a possible replacement for exterior mirrors on series production road vehicles, which would involve safety legislation and driver acceptance issues.
Ullrich believes that the race experience in turn will feed back to production-car design and engineering teams. “I'm sure that we'll be able to return valuable findings to our colleagues in TE. We integrated the system into the vehicle package in an extremely small space and reduced the aerodynamic effects of the camera and energy consumption to a minimum,” he said. “The intensity of the demands in motorsport, such as at the Le Mans 24 Hours, will cause such a system to mature at an accelerated pace. If the digital rearview mirror is introduced in production vehicles in the future, our customers will yet again profit from a motorsport-tested system.”