Text: Vic Rosales / Photos: Vic Rosales | posted May 08, 2008 11:27
Automotive lighting for the car nut
Before all the fancy cat-eye headlamps started like the ones you see in the current Mercedes Benz S-Class, BMW 5 series previous generation Porsche Boxster and 996 Carerra, headlamps were mainly styled with function over form in mind. Very round and fueled by acetylene or oil, headlamps were introduced in the late 1880s. This is the same kind of fuel they would also use for streetlights. Think of Sherlock Holmes with his cobblestone London lit up by torches fueled by acetylene. Not the perfect image but real close. Acetylene was the first fuel for headlamps and was popular because acetylene is resistant to wind and rain. Electricity soon became available but did not catch on immediately because of its short life due to the filament burning out too quickly. These were first found, albeit optional, in 1898 on the Columbia Electric Car from the Electric Vehicle Company of Hartford, Connecticut.
"Dipping" or low beam headlamps were first introduced in 1915 by the Guide Lamp Company. In 1917 Cadillac followed with a system that allowed the light to be dipped by using a lever inside the car rather than requiring the driver to adjust them manually which required them to stop and get out, Another method for adjusting the dim light was the foot lever found in some Ford vehicles. The last headlamps with foot-pedal activated type dip beams were produced in 1991 in the Ford F-series trucks.
For years the style of headlamps remained the same, round and bug-eyed because manufacturers at that time could only produce the reflectors for the round headlamps. Popular headlamp manufacturers like Hella would soon make rectangular shaped headlamps but it was the aerodynamic styling of the Jaguar E-type that brought forward the early headlamp styling concept and evolved it with conventional round lamps faired into the car's bodywork with aerodynamic glass covers, giving that sleek look we are more familiar with today. This was first seen in Europe in 1961.
In 1968 the U.S. DOT prohibited any decorative or protective element in front of the headlamps whenever the headlamps are switched on. Glass-covered headlamps, used on the Jaguar E-Type, the pre-1968 VW Beetle, the Porsche 356, the Citro?n DS and Ferrari Daytona were no longer permitted, and vehicles had to be imported with uncovered headlamps for the US market. This change meant that vehicles designed for good aerodynamic performance could not achieve it for the US market.
In the United States, headlamps were required to be round in shape until 1975. What particular mainstream significance would this for us lay folk? Could you imagine what the TV show Miami Vice would be in the 1980s if Don Johnson as Detective Sonny Crocket with his partner Rico Tubbs did not have his suave Ferrari Testarossa to drive because it?s headlamps were too sleek and sexy? Where would we get our inspiration to wear bright coloured neon suits? And how would we ever receive the kick-ass re-make with Collin Farrell and Jamie Foxx with their even sexier Ferrari F430 in 2007?
In 1983, the 44-year-old US headlamp regulations were amended to allow replaceable-bulb, nonstandard-shape, architectural headlamps with aerodynamic lenses. The first U.S.-market car since 1939 with composite headlamps was the 1984 Lincoln Mark VII. This was the start for super sleek vehicles to enter mainstream America. Before this amendment, cars with headlamps that were contoured to the body were referred to as ?Euro? look headlamps because they were allowed and more common in European vehicles compared to their American counterparts.
Now from the casing, let's talk about the contents of headlamps, the filaments and gases that make up the actual source of light that dictate the color and the intensity of the light we use for the road.
Light for our cars come in many colors, all of which correspond to the Kelvin rating they adhere to. This is called the color temperature. Those really yellow lights we often see on fog lamps and older vehicles are in the 3200k to 4000k rating just like tungsten lamps. While yellowish to white light starts appearing around 4300 kelvin. Anything after that becomes white to bluish, once you reach the 5000k-5400k the color temperature mimics the sun at direct noon while 5500k-6500k is daylight. Now if you are planning on getting noticed, HIDS which are 8000k rated will give you that cool purplish hue that sticks out from 1 kilometer away in the rear-view mirror of the car in front of you. Caveat though! Different colors have different effects on our eyes. Remember that despite purple looking cool when using 8000 kelvin rated bulbs, Mercedes Benz and everyday vehicles like the Toyota Camry use HIDs with 4300k rated HID bulbs, (this happens to be the color temperature of light best for all around driving). Off-roaders still use yellowish 3200k rated and sometimes even 23000k foglamps for these cut through the fog a lot better than higher Kelvin bulbs. The only trade of is that like the 8000k rated purples (and those rated higher), they become strenuous to the eye. On long journeys you may feel your eyes get tired more easily than with light in the 4300k range.
Once you?ve decided what color suit you?ll be wearing, your car and the shoes you?ll use for the night, figure out the kind of tech you want to produce it. Here we?ll see the leaps and bounds automotive lighting has grown since acetylene. We have halogen lamps, High intensity discharge lights and the new up and comer for headlamps, Light Emitting Diodes or LEDs.
Incandescent bulbs are the most common type of light source found in today?s vehicle. They can be found on almost all parts that need lighting which include the turn-signals, night lights, brake lights tail lamps, parking lamps, side marker lamps and even the interior dome lights. They usually use bulbs of 21 to 27 watts, producing 280 to 570 lumens.
Halogens on the other hand are just as popular but only for the forward lighting parts like the headlamps. They are also called tungsten-halogen bulbs and use a filament that burns almost like a regular bulb but with stronger resistance to burnout.
High Intensity Discharge lights or more popularly known as Xenon lights are powered by an electrical charge that goes through an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina tube. This tube is filled with xenon gas and metal salts; hence the name. Compared to incandescent and florescent lights, HIDs have a higher luminous efficacy, which means that it is brighter making less heat than regular halogens. They give a greater amount of light output per watt of electricity input compared to halogens as well.
LEDs or Light Emitting Diodes are the wave of the future. They are made of semiconductor diodes that emits incoherent narrow-spectrum light They last longer than both and can be packaged in shallower assemblies making them more malleable to the designer?s concept. Compared to Halogens and HIDs, they also have a faster reaction time, for when power is applied they rise to full intensity approximately 200 milliseconds (0.2 seconds) faster than incandescent bulbs making them an important safety feature for brake lights and headlamps. LEDs were first used in Central High Mount Brake Lamps (CHMBL) but are entering mainstream through the Audi R8 supercar and the Lexus LS600h. The R8 using them for the low and high beams along with the position (parking) lamp and front turn signals. If you noticed Tony Stark?s suave R8 in the 2008 Iron Man movie, well you?re not alone, those LED headlamps and rear lamps surely complement the sexy Audi.
Neon lights, the same ones seen on advertising boards are also used for automotive lighting, but as a design cue more than a functional road illuminator. Seen on many ?pimped? vehicles on MTV?s Pimp My Ride, neon lights are often connected to the undercarriage of the vehicle to draw attention with its eerie glow at night. Neon lights are pretty to look at but cause a safety hazard when it rains or when crossing roads with clearances very close to the underbody of the car, broken neon lights leave shattered glass on the road and the ballasts that power them, if coming from a cheap manufacturer can explode or break being very open to the harsh environment on our roads.
What can we learn from all this? Be careful with the kind of light you use and replace in your vehicle! If you are using a Honda CRV or Civic with headlamps that use the standard halogen h4 assembly, don?t just think that by putting just any HID kit that you will get the best performance in terms of light visibility from them. Take into consideration that besides from the colour, one has to take note of the amount of real lumens the bulb projects in tandem with the built-in reflectors of your car?s headlamps. With that in mind, please be weary to properly aim your headlights as well. Stronger bulbs improperly aimed can blind incoming traffic or may not be lighting your path at all! All bling is useless if you end up falling off a cliff while going up Tagaytay during a dark stormy and foggy evening.
Lighting for our cars has come a long way. Today we can have a potpourri of tech to accompany our vehicles lighting system. From automatic headlamps that turn on by themselves when they sense the environment has significantly darkened to parkway lights that leave the headlamps on at a press of the keyfob to light your path for a set period of time to let you get through the drive way. We have headlamps that look retro like the Toyota FJ Cruiser but contain the newest in reflector technology and HIDs for headlamps that look like headlamps but aren?t! (Check out the Rolls Royce Phantom with rectangular bulbs on the front, guess what, those aren?t the headlamps, the round ones next to the grill are!). Retrofitting has now become the norm for Xenon bulbs, albeit with some compromise for high beams. People can easily exchange halogen bulbs for HIDs with the ballast harness needed to spark them to life. The harder path goes as far as disassembling then reassembling headlamp cases to fit non-standard parts from other vehicles with OEM HIDs. (Check the forums for people who have transplanted Honda S2000 HID internals and fitted them to 2nd generation Honda CRV headlamp assemblies). Turn signals and brake lights using LEDs shine brighter and faster than previous light sources giving that extra sense of urgency when braking hard or taking a turn.
As technology progresses as seen from the evolution of the light bulb, the future for automotive lighting is only likely to get brighter.