Audi was the first automobile manufacturer to recognize the potential of revolutionary LED lighting technology and then incorporate it during development of its vehicles. The brand with the four rings has since acquired a technological edge putting it years ahead of the competition, and is a key driver of this innovation. Crucial for the exterior design: Not only during the day but also at night, all Audi models are recognizable at a glance thanks to LED daytime running lights. And each Audi has its own personality: The sweeping light strip on the Audi A4 exudes elegance. And that of the Audi R8 radiates strength and dominance: Its headlights were designed and constructed entirely on the basis of energy efficient and environmentally friendly LED technology.
A tiny dot on your finger, as minute as a grain of sand. That is all. A layperson might just carelessly flick it away – but it electrifies those in the know. After all, this speck of material uses electrical energy to generate more white light than any conventional light source in the world. A light-emitting diode, or LED, is a semiconductor device – just a square millimeter in size – which boasts a remarkable physical property. It can convert electrical energy directly into light and is unbeatably efficient when it comes to energy consumption. Today’s xenon and LED headlights are four times more energy efficient than halogen headlights. And by 2018, LED technology should be about eight times more efficient than halogen light. In addition, LEDs excel due to their practically indefinite service life and react up to ten times more quickly than traditional incandescent bulbs.
This success story began five years ago in Detroit. At the North American International Auto Show, Audi presented the Pikes Peak quattro concept study. This elegant SUV, inspiration for today’s Audi Q7, garnered attention with the world’s first fog lights equipped with high-performance light-emitting diodes. Integrated into the broad bumper as striking strips of light, the fog lights were a sensation not merely in a technical sense. The strip-shaped lights were also aesthetically pleasing and very popular with the public.
Soon thereafter, the 12-cylinder Audi A8 went into series production as the world’s first vehicle with LED daytime running lights. High-performance light-emitting diodes as a light source for headlights? Nothing of the sort had ever been done. “Audi blazed trails with LED technology. And even though we’re years ahead of our direct competitors, this field continues to bear tremendous potential for us. Our research counts on the ‘Vorsprung durch Technik’ typical at Audi and no one can imagine our designs without it,” says Dr. Wolfgang Huhn, Head of the Light and Visibility Department at Audi.
Unprecedented scope in vehicle design
The tiny light sources present designers with spectacular opportunities. Stefan Sielaff, Audi’s Head of Design, explains: “LEDs unlock the door to unrealized design possibilities for exterior design and interiors alike.” For example, a number of lightemitting diodes can be combined to create various shapes, which can ultimately result in a distinctive visual appearance. The taillights of the Audi A6 Avant are likely the best-known example of any tail end. These light-emitting diodes in a ring-shaped array have become every bit as instantly recognizable as the sweeping LED daytime running lights at the front end of the Audi A4. Headlights naturally play a pivotal role in a vehicle’s light design. An appealing front end with one-of-a-kind lights makes a car as well as its personality and the brand recognizable at a glance. Sielaff adds: “LED daytime running lights epitomize this fact.
Every light design is different, yet there’s no mistaking that every single vehicle is an Audi. Our daytime running lights cemented the visible persona of Audi models on the road and hone our progressive, sporty design.”
For quite some time, drivers have been able to spot an approaching Audi from far away. But different configurations of LED daytime running lights now permit distinct differences among the Audi models – even in the dark. A strip of light can be designed to underscore a vehicle’s character, just as eyeliner emphasizes an eye.
This fundamentally alters the body language of Audi models. “The lighting configuration of yesteryear – the radiator grille along with the round lights – called to mind the face of a friendly bear,” notes André Georgi, Senior Designer of Lighting Systems. Nowadays: “The LED daytime running lights for the A Series, e.g. on the A4 and A5, look determined, elegant, and dynamic. The lights on the Audi Q5 and Audi Q7 appear especially broad and powerful. And the LED daytime running lights on the R8 symbolize the horns of a bull charging full speed ahead, bursting with vigor and pride.”
Speaking of the Audi R8: This sports car constitutes the spearhead of Audi’s light strategy and is optionally available with the world’s first all-LED headlights. In addition to the daytime running lights, the turn signals as well as low-beam and high-beam headlights are all executed by means of light-emitting diodes. The first all-LED headlights represent the triumph of an idea for Audi. Huhn explains: “A lot of people initially viewed this development as a mere marketing gimmick. Yet everyone who has seen these lights in action is not only astonished by the excellent output, but also thrilled with the homogenous distribution of light and the agreeable, daylight-esque color of the light.
Audi’s light strategy also benefits from something quite different, namely a psychological phenomenon: “Bright light created by small, compact light sources is unpleasant for the human eye. The combination of headlights and LED daytime running lights enlarges the light source, thus eliminating a nuisance,” explains Georgi.
Ideas and visions from technology and design
The true key to success in Ingolstadt, however, is the daring to break new ground coupled with close teamwork. “The remarkable cooperation between design and technology at Audi is surely unique in the automotive industry,” adds Georgi. The design process is initiated by developing and defining a vehicle’s character. The light designers and engineers from Technical Development play a hands-on role in this process from the word go. For example, one of the engineers – fittingly nicknamed “The Bridge” by his colleagues – works right in the middle of the Design Department. Conversely, a lot of the technically relevant headlight components are designed by Technical Development. This close rapport ensures that the departments confer with one another every day.
As a vehicle’s exterior takes shape, the proportions of the headlights and the taillights are defined. Georgi says: “It’s a truly intensive process for us to develop new headlights; every idea and every vision from Technical Development and Design come together.”
Audi’s light designers turn to industrial design and architecture when they require inspiration for new ideas. In fact, more and more architects are integrating high-tech LEDs into their plans for new buildings, thus joining a worldwide shift toward energyefficient lighting. Experts forecast that LEDs, energy-efficient and maintenance-free sources of light, will also become the first choice for indoor lighting.
But now back to vehicle lights. Another crucial muse for Audi light designers is nature. “Nature often shows us the way, allowing us to learn just how simply and effectively processes can be executed,” explains the light designer Georgi. The most recent example of this is the taillights we developed for the Audi A1 Sportback concept, which was recently unveiled to the world in Paris. Audi designers were inspired by the lattice structure of a dragonfly’s wing. The design of the taillights impressively demonstrates the relative simplicity required to construct a very large, stable and light surface. Georgi says: “With our bionic design, we transferred this constructional conception to the Audi A1 concept’s taillights, which needed to be lightweight because they are integrated in the tailgate.” The headlights of the Audi Shooting Brake Concept are an additional illustration of nature permeating Audi design. Reminiscent of an open pine cone, reflector shells arranged successively in concentric circles harness the light of each individual diode to create lighting which is powerful and consistent. The headlights in the middle, on the other hand, are shaped like blossoms.
Greater safety, lower consumption
Yet LEDs are capable of even more. They can also reduce a vehicle’s fuel consumption. When daytime running lights become mandatory in the European Union in May 2011, Audi models with on-board LED technology will be ahead of the competition. Drivers in a lot of European countries – such as Italy, Denmark, Finland, Estonia, and Sweden – already must use their lights during the day. As a result, just one vehicle’s conventional low-beam headlights, taillights, and license-plate illumination consume some 200 watts – which the alternator must constantly generate. By comparison, a mere 15 watts is required to power the new Audi A4’s modern LED daytime running lights, which have the added advantage of far better visibility for other road users. All in all, that equates to a decrease of about 0.2 liters of fuel per 100 kilometers and about 4 grams fewer CO2 emissions per kilometer. A statistical example clearly illustrates the significance of these figures: Thanks to this new technology, the Audi models with LED daytime running lights sold in 2008 alone will consume – during just their first year in use – about 10 million fewer liters of fuel and emit approximately 25,000 fewer metric tons of CO2.
Such arguments are persuading more and more car buyers. In addition to the striking design, the high-tech lights’ stellar energy efficiency is yet another reason to opt for them. Consequently, a majority of people who buy an Audi A3 or A4 now order daytime running lights with LED technology. This success provides a sense of validation for the engineers, design engineers, and light designers in Ingolstadt – but also calls to mind an arduous journey. “We first had to experiment a great deal before we could employ the medium of LED to achieve the lighting performance of headlights,” explains Stephan Berlitz, Head of Lighting Technology and Electronics in Ingolstadt.
The discovery of digital light
Berlitz reminisces aloud: “One day, a supplier called to tell me that white LEDs with 18 lumens per watt would soon be on the market. Suffice to say, that immediately got my attention.” Lumens per watt are the horsepower of light: They light up the eyes of light developers just as the words torque and power light up the eyes of engine experts. For the sake of comparison, an ordinary household light bulb generates about 20 to 25 lumens per watt. A modern passenger vehicle’s xenon headlights, on the other hand, are very energy-efficient and create some 80 lumens per watt. Though the 18 lumens generated by the first LED headlights in the Pikes Peak concept are old news, they created quite a stir in those days. The next generation of white high-performance LEDs will hit the market next year with a whopping 100 lumens per watt, thus surpassing the efficiency of xenon lights for the first time. This can be traced back to dramatic developments. “Light-emitting diodes are similar to computer chips. Every two years there’s an increase in output of about 30 percent,” explains Berlitz, “and we’ll soon be able to create so much light with LEDs that entirely new applications will become possible.”
Digital light, as Berlitz calls this new light technology, can be made more or less bright electronically and precisely adapted to a driver’s needs. Audi developers are convinced that future generations of headlights will react to weather conditions, a vehicle’s speed, the distance between vehicles, and potentially dangerous objects.
Intelligent light for every driving situation
Developers exploit the tininess of LEDs to realize new ideas and increase light output: They tightly bundle several light-emitting diodes to create modules known as LED arrays. These arrays are extremely flat, very compact and require much less space than conventional light sources such as halogen bulbs or xenon burners. Because of this, and thanks to reflectors as well as sophisticated electronic controls, it is possible to realize very complex lighting functions in the tightest of spaces. Cornering light, for example, has traditionally been executed via complex mechanical means in headlights.
But Audi developers envision even better things for future generations of headlights. Their motto: The right light for every driving situation. Huhn explains: “We’re striving to create intelligent headlights and taillights which think and anticipate in the interest of enhancing a driver’s safety and comfort.” For example, there are already high-beam headlights in pre-series development which will allow drivers to navigate roads at night without temporarily blinding oncoming drivers. This is made possible by a variable distribution of light: An electronic system continuously calculates the distance to any approaching vehicles to ensure that the road ahead is ideally illuminated at all times – without irritating oncoming drivers.
In addition to such successes in the field of LED technology, Audi is also pursuing the further enhancement of existing technologies. The brand with the four rings is, for example, the only European manufacturer which has resolutely switched to xenon lights that contain no mercury. “Our engineers do everything they can to champion environmentally friendly ideas. For instance, we are the only European manufacturer which uses mercury-free xenon lights. Until recently, this had been deemed all but technically impossible. But following our triumph, the EU recently banned xenon which contains mercury as of January 2012,” says Huhn. LEDs typically contain no mercury and thus tend to lend themselves to environmentally friendly disposal.
Trend toward individualized light
LEDs also present new opportunities for interior lighting. Similar to interior architecture, lighting scenarios are imaginable which would make it safer to operate the vehicle at night, render the interior considerably roomier, or impart a certain atmosphere.
The optional interior lighting package with ambient lighting in the Audi A8 quite simply raises the bar. The true ingenuity of the ambient lighting of the A8 lies in the possibilities for customizing the interior lights. The driver can dim the light and configure various lighting profiles via the MMI. These profiles respond as appropriate to certain driving situations – when a vehicle’s interior is illuminated by lighting within cities, for example, or becomes dark on unlit rural routes.
When it comes to the lighting in vehicle interiors, developers are confronted with few limits. Safety and comfort are top priorities. Berlitz explains: “Think of a mountain hut at night. As you’re passing through an alpine meadow, you spot the warm light glowing through the hut’s windows. The light triggers that same cozy sensation you feel when you arrive home.” We want future Audi models to elicit that same exact feeling. Berlitz adds: “Just imagine: You press a single button on your remote control and the entire vehicle springs to life. The ‘headlight eyes’ awaken and an inviting light fills the vehicle’s interior as if to say: Welcome home!