Halogen projector headlamps are standard on the Kenworth T660. Their low beams cast 40 percent more light down the road than sealed-beam lamps and last longer.
The simple sealed-beam headlamp, basically a bulb in a vacuum-sealed case, is heading the way of the dodo. Truck manufacturers and aftermarket shoppers are switching to newer technologies. One advance has been the composite reflector headlamp. It bounces the light off a diamond-shaped reflector on the back bounces the light off a diamond-shaped reflector on the back of the lamp, giving more output than a normal sealed-beam lamp. Other developments have been halogen and high-intensity discharge headlamps.
These newer technologies cost more, but generate more light, produce more even illumination and last longer than sealed-beam lighting. Wire Connections, for example, sells complex-reflector headlamps for $80 to $90. HID lamps can go for as high as $300.
The longest-life sealed-beam bulb commercially available is Truck-Lite’s halogen-based, 7-inch round replaceable headlamp, says Brad Van Riper, Truck-Lite vice president of research and development. It was designed for commercial trucks with a higher mounting height, enabling truckers to see farther. It retails between $50 and $60 and is rated to 1,200 hours on low beam, 250 hours on high beam.
“The common sealed-beam headlamps – 5 by 7 inches, 4 by 6 inches – were originally designed by passenger car companies,” Van Riper says. “Headlamps for passenger cars that are put on trucks reduce the amount of foreground lighting, and the beam often disappears quite early because it is projected further down the road.”
The light pattern is important, too, says Steve Howser, new product development manager for Grote Industries. Uneven patterns cause drivers’ eyes to focus on the brightest spots, he says. Grote headlamps uniformly provide “a smooth gradient in the pattern, not a bunch of bright spots,” Howser says.
The new technology is not limited to the aftermarket.
“Freightliner’s factory-installed headlamps with long-life halogen bulbs are designed to provide maximum visibility and better light distribution on the road,” says Dan Wells, Freightliner director of exterior design. The headlamps “allow for fast bulb replacement and aiming once the trucks are in service,” Wells says.
Truck makers also have improved lighting capabilities through design elements that surround the headlamp. They have moved away from halogen sealed-beam designs “in favor of more aerodynamic designs with a composite reflector and polycarbonate lenses,” Wells says. The designs incorporate easily replaceable long-life halogen bulbs, he says.
“The composite headlamp system offers better light distribution and more even illumination,” Wells says. “Ease of maintenance is increased with the composite headlamp design since customers don’t need any tools to replace the halogen bulbs.”
Truckers should consider application when choosing headlamps, says Bill Downs of International. For example, while a sealed-beam system might be the best choice for severe service, an over-the-road tractor would do better with the aerodynamics and lighting advantages of a composite headlamp, he says.
Factors to consider include cost of replacement, percentage of night driving and average vehicle speed, Downs says. “Many consider cost factors such as bulb replacement and accident repair. Others look at appearance and how that affects aerodynamics and image.”
Two of the most important characteristics of headlamps are life and cost, says Landon Sproull, Peterbilt’s chief engineer. The 388 and 389 Petes boast complex-reflector headlamps that increase forward lighting by 226 percent and improve bulb life by 600 percent, compared to sealed-beam lights, the company says.
High-intensity discharge headlamps have even longer lifespans, Sproull says. One HID, for example, contains xenon gas. “It is like a spark plug that has a filament going across it, a blue light that is mixed into the gas,” Sproull says. “It is very high intensity.”
While every heavy-truck maker in Europe offers xenon HID headlamps as an option, the U.S. market share of xenon-equipped trucks is only about 10 percent, says Marc Ritzer of the aftermarket marketing division of Hella Inc.
Hella’s xenon HID headlamps are offered as an option on Kenworth’s new aerodynamic T660. The model comes standard with halogen headlamps that provide 40 percent more light than sealed-beam headlamps and last three times longer. Kenworth says the xenon HID lamps generate 75 percent more light and last 11 times longer than a sealed-beam lamp.
Aftermarket xenon HID headlamps sold by GoHID cost between $100 and $300. A Xenon HID may be eight times as expensive as a sealed-beam or complex reflector headlamp, but the cost per hour drops because the lifespan is so much greater, Sproull says. While a sealed beam has a life of 300 hours, an HID lamp can last 2,000 hours.
What might be the next advancement in headlamp technology is already well known to truckers: the light-emitting diode. LEDs “draw less power, which is good,” Sproull says. And they have an amazing 15,000-hour life – roughly the same as the truck itself.
A lamp could be made not with one large bulb but with a cluster of LEDs, to allow for frame-specific customization. This ability to shape the light would allow for more aerodynamic profiles and more control over illumination. “Instead of just high/low beams, you could have a side beam,” Sproull says.
LED applications are cost-prohibitive right now, but automotive designers could begin using them as early as next year, Sproull says. “Trucking could get them by 2010.”