New headlight technologies target performance and energy efficiency

Jan. 1, 2020
Two of the top priorities in the automotive industry today are to enhance safety and be more energy efficient ? and the latest developments in automotive lighting are helping car manufacturers make progress in both of those areas.
Engebretson ABRN collision repair auto body repair OEM automakers changing technology headlights Two of the top priorities in the automotive industry today are to enhance safety and be more energy efficient – and the latest developments in automotive lighting are helping car manufacturers make progress in both of those areas.

Key developments include new headlights based on light-emitting diodes (LEDs) and high-intensity discharge (HID) technology. Enhancements also are being made to the halogen technology that remains the mainstay of automotive headlights.

In recent years, motorists have grown increasingly familiar with the bright, almost blue-looking light of HID headlights on high-end models. Sam Cribari, product manager for lighting component supplier Philips, explains the workings of HID headlights, also known to some as xenon after the type of gas used inside.

"Instead of a filament, there's two electrodes and a light arc that fills the space between them," says Cribari. "This results in a longer lifetime and greater light output."

The resulting light is whiter than that of conventional halogen headlights, according to Greg Bibbo, product marketing manager for headlight manufacturer Sylvania.

"The eye is more perceptive of that than more yellowish halogen," Bibbo says. "Drivers pick up the features on the road better." The net result is that drivers have better reaction time, which ultimately enhances safety.

The downside to HID lighting is that it's more costly than halogen lighting, particularly when the requirement to protect against glare is factored in. HID lights are so bright that, if not properly aligned, they can negatively impact the vision of oncoming motorists. European regulations require any headlight emitting more than 2,000 lumens, including all of today's HID headlights, to be equipped with automatic levelers and to be self-washing, according to Steffen Pietzonka, regional vice president of marketing for headlight manufacturer Hella. If the lenses on HID headlights become dusty, it can cause the light to disperse unpredictably, potentially increasing glare.

Until recently, a third alternative in lighting technology – the light emitting diode, or LED – was reserved for non-headlight applications, including interior lights, turn signals and brake lights. But headlights that use an array of LEDs now appear on a few vehicles, including the Cadillac Escalade (see page 26).

"All the major manufacturers are in some way actively developing them," says Bibbo. "Energy and performance are driving manufacturers to LED."

LED headlights are costlier than halogen – and about the same, or even more costly, than HID, depending on whom you ask. But on the plus side, they use considerably less energy than the other technologies. LED headlights are about 95 percent more efficient than halogen, according to Jonathan Dunlap, another Sylvania product marketing manager. This ultimately translates into fuel savings, he said.

More energy efficient headlights may be particularly critical for electric and hybrid electric vehicles. To conserve energy, the 2010 Toyota Prius hybrid uses LED low beams so owners can driver further at night on a single charge, Dunlap said.

Another advantage of LED headlights in comparison with halogen and HID is that they have longer life, according to Pietzonka. The average lifetime of a halogen headlight is about 1,000 hours. In comparison, he said an HID headlight lasts about 3,000 to 4,000 hours and an LED headlight lasts more than 6,000 hours, which is the lifetime of the average automobile.

LED headlights also are less yellow than halogen lights, approaching HID in their whiteness and brightness and that should improve driver response times, Bibbo said.

Drivers following cars that use LEDs for brake lights also should experience faster response times, according to Bibbo. That's because LEDs respond more quickly to the brake pedal being pressed than the incandescent lights that traditionally have been used for that purpose. "It saves about 15 feet in stopping distance," Bibbo says.

A final benefit of LEDs is on the design side. Because they use multiple miniature lights, those lights can be laid out in a variety of form factors, and as Dunlap explains, "We're seeing a lot of manufacturers trying to create a brand-identifying look so people can instantaneously recognize the manufacturer." Dunlap and Bibbo point to Audi and Saab as two companies that are striving to create their own distinctive looks.

For now, however, halogen headlights continue to dominate the mainstream automotive market, and as Bibbo notes, "When a vehicle comes off the showroom, the headlights are optimized for life, acceptable brightness and performance. Manufacturers are really looking for lights that last through the warranty period."

When it comes to the replacement market, however, some manufacturers have introduced halogen headlights that offer enhanced performance and energy efficiency. In the event that a car's headlights need to be replaced after a collision, some owners might prefer to move to some of those products. Sylvania's Silver Star Ultra headlights, Bibbo said, are 50 percent brighter than conventional halogen headlights. The company said its new Ecobright line is 25 percent brighter and uses up to 21 percent less energy than products built to SAE maximum design specifications.

Another new development on the halogen side is the use of bi-halogen light sources. Cribari said that conventional halogen light sources use two-filament bulbs, with one filament for the high beams and the other for the low beams. "But bi-halogen has one filament doing both with some type of shutter system," he says. The advantage is a smaller form factor, which could be increasingly important when a new European requirement to provide dedicated running lights takes effect.

Manufacturers of all types of headlights are continuing to enhance headlight performance, often in some creative ways. Hella, for example, offers HID and LED headlights – available on the new Audi A8 – that automatically provide more light in the far for-field when the vehicle reaches a certain speed.

Hella also provides a camera-based light system to Mercedes for use on its E-class models that automatically adjusts the brightness of the car's beams based on the location of any oncoming cars. Unlike with traditional headlights, which have only low- or high-beam settings, Pietzonka says, "it's possible to adjust to a specific in-between setting based on the position of the other car." Another headlight manufacturer, Valeo, has introduced similar functionality in its BeamAtic front lighting system, which a spokeswoman said will be offered as optional equipment on several vehicles.

As for future developments in automotive headlights, Hella plans to launch a camera-based system that allows high beams to function even when an oncoming vehicle is present by providing a darker area within the beam that is activated when the vehicle approaches. The system will be available on vehicles from a European manufacturer in 2010, according to Pietzonka.

Pietzonka also says to look for 25-watt HID headlights, which will be somewhat less bright than the 35-watt units available today, but which will be exempt from the European automatic leveling and washing requirements.

Philips is gearing up to meet another European regulation that will require mercury-free HID lights and Cribari said he expects to see that technology adopted in North America also as car makers seek to offer more models that can be sold worldwide without variation from market to market.

Valeo, meanwhile, is working on an LED fog lamp, the company spokeswoman said.

As the industry sees greater use of LED and HID headlights, it will be important for technicians to take care to select the same technology when choosing a replacement part – and to make sure that the vehicle manufacturer approves the replacement part. Correctly aligning headlights has always been an important part of the replacement process and that's even more critical as brighter LED and HID headlights come into play.

Bibbo offers a couple of other tips. Headlights dim over time so they should be replaced in pairs. "If a crash only consumed one side, they should replace both," he says.

He also advises technicians to wear gloves when handling headlights. Finger oils could accelerate the corrosion on halogen lights, which operate at very high temperatures, he said.

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