Headlight: Encyclopedia II - Headlight - History of automotive headlights

Headlight - History of automotive headlights

The earliest headlights were fueled by acetylene or oil and were introduced by drivers in the late 1880s. Acetylene was popular because the flame was resistant to wind and rain. The first electric headlights were introduced in 1898 on the Columbia Electric Car from the Electric Vehicle Company of Hartford, Connecticut, but they were optional. "Prest-O-Lite" acetylene lights were offered by a number of manufacturers as standard equipment for 1904, and Peerless made electrical headlights standard in 1908. In 1912, Cadillac integrated their vehicle's Delco electrical ignition and lighting system, creating the modern vehicle electronics system.

"Dipping" (low beam) headlights were introduced in 1915 by the Guide Lamp Company, but the 1917 Cadillac system was much more useful as it allowed the light to be dipped with a lever inside the car rather than requiring the driver to stop and get out. The 1924 Bilux bulb was the first modern unit, having the light for both low (dipped) and high (main) beams of a headlamp emitting from a single bulb. A similar design was introduced the next year by Guide Lamp called the "Duplo". In 1927, the foot-operated dimmer was introduced and would become standard for much of the century. The last vehicle with a foot-operated dimmer was the 1991 Ford F-Series. Fog lights were new for 1938 Cadillacs, and that company's 1954 "Autronic Eye" system automated the switch between high and low beams.

The standardized 7 inch (178 mm) sealed beam headlight was introduced in 1940, and was soon required for all vehicles sold in the United States. Britain, Australia and other British Commonwealth countries, as well as Japan, also made extensive use of sealed beams, but they were never widely accepted in Europe, leading to different front-end designs for each side of the Atlantic for decades. The U.S. DOT also in 1968 outlawed covered headlights (as famously used on the Jaguar E-Type, VW Beetle, Porsche 356 and Ferrari Daytona), further altering the look of European models sold in the United States. In 1984, US regulations once again allowed replaceable-bulb, nonstandard-shape headlamps. The first U.S.-market car since 1939 with composite headlights was the Lincoln Mark VII of that year. These U.S.-market composite headlamps were frequently, though incorrectly, referred to as "Euro" headlamps. Despite their aerodynamic, nonstandardized shape and replaceable-bulb construction, these headlamps conform to the U.S. Department of Transportation Federal Motor Vehicle Safety Standard No. 108 (FMVSS 108) standard, and not the more commonly used Economic Commission for Europe / European Economic Community (ECE/EEC) standards.

Directional (steering) headlights were a notable feature of the 1948 Tucker, but the technology went back to the 1920s Packards. The first volume-production car with steerable headlights was the 1967 Citroën DS. The technology was slow to gain acceptance, but is today offered on a number of luxury vehicles, including models from Lexus, Infiniti, Porsche, BMW, Mercedes-Benz, Audi and Volkswagen. There is a pan-European-and-Japanese working group steering development, implementation and standardization of steerable headlamps, which are now known as "AFS" (Advanced Frontlighting System") or "bending light".

In 1954, Cibie introduced an automatic headlight leveling system linked to the vehicle's suspension system to keep the headlamps correctly aimed regardless of vehicle load. The first vehicle to be so equipped was the Panhard Dyna Z. Beginning in the 1970s, Germany and some other European countries began requiring remote headlamp leveling systems by means of which the driver could lower the aim of his lamps from the driver's seat, to avoid glaring other drivers in the event he was carrying a heavy load that would tend to cause the front of the car to point upward. This requirement spread slowly at first, but picked up speed to the point where most European countries required this equipment by the early 1990s. xenon HID headlamps and very high output halogen bulbs are required in Europe to have automatic leveling systems that keep the beams aimed correctly regardless of vehicle attitude, without any effort on the part of the driver. These leveling systems are permitted but not required outside Europe.

Quad headlights were introduced in 1952 when the Prevost Car company included them in its Citaden bus model. Cadillac, Chrysler and Nash placed them (using one high/low and one high-beam 5¾ inch (146 mm) sealed beam on each side of the car) in some of their car models for the 1957 model year. These lamps had some photometric advantages, but the primary advantage was the styling novelty permitted by the use of two small rather than one large lamp per side of the vehicle.

Rectangular lamps were first used in 1961. Developed by Cibie for the Citroën Ami 6 and by Hella for the German Ford Taunus, they were prohibited in the United States where round lamps were required until 1975, on the Cadillac Eldorado. By 1979, the majority of new cars now had the square headlights. Again, the U.S. permitted only two standardized sizes of rectangular sealed-beam lamp: A system of two 200 mm x 142 mm high/low beam units corresponding to the existing 7" round format, or a system of four 165 mm x 100 mm units (two high/low and two high-beam) corresponding to the existing 5¾" (146 mm) round format.

Pop-up headlights were introduced in 1937, on the Cord 812. They were mounted in the front fenders. The 1942 De Soto also had this feature, which reappeared in the 1963 Corvette Stingray. When the lights were turned on, they would appear from inside the car's front bumper. Many famous cars to use this feature include the Dodge Charger, Ferrari Testarossa, Mazda RX-7 and MX-5 Miata, Dodge Daytona, Pontiac Firebird, Nissan 180SX and 300ZX, Toyota Sprinter Trueno, Celica and Supra, Honda Accord, Prelude and NSX and Buick Reatta. The Corvette itself continued to use pop-up headlights until it was redesigned for 2004.

Halogen technology makes incandescent filaments much more efficient, and Europeans chose to use this extra efficiency to produce much more light than was available from nonhalogen filaments at the same power consumption. Unlike the European approach which emphasized increased light output, most U.S. low beam halogens were low current versions of their nonhalogen counterparts, producing the same amount of light with less power. A slight theoretical fuel economy benefit and reduced vehicle construction cost through reduced wire and switch ratings were the claimed benefits. There was an improvement in seeing distance with U.S. halogen high beams, which were permitted for the first time to produce 150,000 candelas per vehicle, double the nonhalogen limit of 75,000 candelas but still well shy of the international European limit of 225,000 cd. After replaceable halogen bulbs were permitted in U.S. headlamps in 1983, development of U.S. bulbs continued to favor long bulb life and low power consumption, while European designs continued to prioritize optical precision and maximum output.

The first halogen bulb for vehicle use, the H1, was introduced in 1962 by a consortium of European bulb and headlamp makers. This bulb has a single axial filament that produces 1500 lumens when operated at 13.2 volts. H2 (55w, 12.8 volts, 1820 lumens) followed in 1964, and the transverse-filament H3 in 1966. H1 still sees wide use in low beams, high beams and auxiliary fog and driving lamps, as does H3. The H2 does not see wide use anymore because it is complex to make and to service. The H2 bulb is no longer approved for new lamp designs. The use of H1 and H3 bulbs was legalized in the United States in 1997. More recent single filament bulb designs include the H7, H8 (35w, 730 lumens), H9 (65w, 2100 lumens), and H11 (55w, 1200 lumens) bulbs.

The first dual-filament halogen bulb (to produce a low and a high beam with only one bulb), the H4, was released in 1971. The U.S. prohibited halogen headlamps until 1978, when halogen sealed beams were released. To this day, the H4 is still not legal for automotive use in the United States. Instead, the Americans created their own very similar standard (HB2/9003). The primary differences are that the HB2 sets more strict requirements on filament positioning, and that the HB2 are required to meet the lower maximum output standards set forth by the United States government. The H4 is limited to roughly 60% of its potential low beam output due to internal shielding required to fit two filaments in the bulb. More recent dual filament bulb designs include the H13.

The first U.S. halogen headlamp bulb, the 9004/HB1, is a transverse dual-filament design that produces 700 lumens on low beam and 1200 lumens on high beam. The 9004 is rated for 65 watts (high beam) and 45 watts (low beam) at 12.8 volts. Other U.S. approved halogen bulbs include the 9005/HB3 (65w, 12.8V), 9006/HB4 (55w, 12.8V), and 9007/HB5 (65/55 watt, 12.8V). With their plastic bases, the 9004, 9005, 9006, and 9007 are simply not suited for higher wattage bulbs. The bulbs use electrical contacts that are much too small to handle the excess current. Further, many American headlights are designed such that throwing more light at them will simply result in more glare for oncoming traffic.

The first halogen filament polyellipsoidal "projector beam" automotive lamp was the Super-Lite auxiliary low beam, produced in a joint venture between Chrysler Corporation and Sylvania and optionally installed in 1969 and 1970 full-size Dodge automobiles. It used an 85 watt transverse-filament halogen bulb and was intended to extend the reach of the low beams during turnpike travel when low beams alone were inadequate but high beams would produce excessive glare. Projector main headlamps first appeared in 1983. Developed more or less simultaneously in Germany by Hella and in France by Cibie, the projector low beam permitted accurate beam focus and a much smaller-diameter (though much deeper) optical package for any given beam output. The 1986 BMW 7 Series was the first to use projectors for low beams. Projector and CAD technology allowed the development of reflector headlights with non parabolic, complex-shape reflectors. First made by Valeo under their Cibie brand, these headlights would revolutionize automobile design. The 1987 Dodge Monaco/Eagle Premier was the first U.S.-market car with complex-reflector headlamps, while the 1990 Honda Accord was the first U.S.-market car with such headlamps employing a completely clear, nonfaceted front lens.

High-intensity discharge systems were introduced in 1991's BMW 7-series. European and Japanese markets rapidly came to prefer HID headlamps, which have as much as 50% marketshare in those markets, but the technology was slow to catch on in North America. 1997's Lincoln Mark VIII was an early American effort at HIDs; it was also the first and only car with DC HIDs.

Adapted from the Wikipedia article "History of automotive headlights", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki