Audi, Hella team on production matrix LED headlights for new A8

  • 04-Nov-2013 02:40 EST
Audi 10-13 A8 Matrix LEDs AT130079.jpg

High beam division between vehicles and pedestrian alert is possible for the new Audi A8's matrix LED system.

Uwe Päseler is a night rider in cars with technology that would not have seemed out of place in the 1980s TV sci-fi series’ Pontiac Firebird TransAm, KITT, driven by Knight Rider David Hasselhoff.

Päseler’s night-riding job, though, is as a key member of Audi’s Headlamp Development Project Management team. Working with specialists from technology partner Hella, the team has brought production matrix LED headlights to the latest version of the A8.

The system, called MatrixBeam, runs permanently on high beam with subtleties that include the ability to dim down for multiple “targets,” providing long-range high beam illumination that can straddle both an approaching vehicle and one traveling ahead, without dazzling the occupants of either.

“This is a totally new system,” said Päseler. “We have extensive LED experience [LEDs were used by Audi’s R18 e-tron Le Man 24-hour race winner; its headlight range was around 800 m] and we considered how we could switch them off individually to split light diffusion. We have achieved that for the new A8.”

Two years ago, the company showed SAE Magazines a concept version of the system. It was a challenging program that demanded integration by lighting, software, and optical engineers and specialists, with the added complexity of integrating the system within the styling confines of the new-generation A8’s headlamp dimensions.

“It is not a large headlamp and it had to contain other functions, including ‘moving light’ turn indicators,” he explained. “We did a lot of driving at night to determine the perfect performance that was essential to shut down high beam very quickly so that oncoming vehicles would not be blinded, but not so quickly that the action would make the driver nervous.”

Active real environment testing took about a year and many thousands of kilometers.

Each headlamp has 25 diodes divided into groups of five, each of which shares a common reflector, allowing dimming to be varied. To operate MatrixBeam, the driver uses the headlight system’s “auto” function and selects high beam. Activation is from 30 km/h (19 mph) in an urban environment and 60 km/h (37 mph) outside it. When entering a city, the combined 50 LEDs are dimmed.

A multifunction camera (it can detect roadside warning signs) is placed behind the car’s rearview mirror. When other vehicles are detected, the LEDs are dimmed (or “masked out” as Audi puts it) and then returned to high beam to provide a very bright, homogenous light. The company describes this as a “highly distinctive crystal-like glow.”

The system can handle up to eight “targets,” including the presence of pedestrians, who get three headlamp flashes (marking lights) to draw the driver’s attention to their presence and warn the pedestrian of the approach of the vehicle.

The dimming system can be overridden by the driver if required.

Unlike a conventional headlight system, MatrixBeam requires no mechanical parts and is an ultralow energy technology.

The LED headlamps of the A8 also include cornering lights, adjusting the focal point of the light using targeted brightening and dimming in the direction of the bend. When linked to Audi’s MMI Navigation-plus technology, which provides predictive route data, the cornering lights activate momentarily before the steering wheel is turned.

The turn indicators use blocks of LEDs to blink at 150-ms intervals instead of conventional flash intervals.

Regarded by Audi as essentially a safety system, MatrixBeam is expected to gain wide legal acceptance by European transport legislators, with other countries following.

Päseler says Audi’s lighting research continues with new programs: “We are looking for the ‘perfect’ light—like daylight. LED already provides quasi-daytime light. The next step? Even more light—much more—with systems perhaps integrated with other vehicles using connect technology.”

Other Audi model range flagships are expected eventually to benefit from the latest A8 technologies, including the MatrixBeam system, particularly apposite for high-performance cars, of which the company is producing ever more examples.

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