History of the Lighting System
Naturally the first motor vehicles adopted their lighting from that of carriages, if these had any lighting at all. These were nothing other than oil lamps which were constantly supplied with oil from a small container. By the way, before the invention of the internal combustion engine, the oil lamps (used in the home) were one of the principal reasons for the search for crude oil. For horse and cart this light was sufficient, even then, the rays of light were radiated onto the roads by a parabolic reflector and a glass cover.As the motor vehicles became faster, and were used more at night, the acetylene light was introduced. It was comparable with the light of todays oxy-acetylene welding, however, it was dangerously explosive, required constant refilling and generally was a system which needed constant checking and care. The electric arc-light could be roughly compared to the modern xenon lamp.
Electric light was not very well liked, right up to the second decade of the 20th century, after all, the battery had to be recharged over and over again. With the event of the electric starter (in America), an integrated system of current production and storage was slowly introduced into the vehicles. With the introduction of the generator in 1913, the electric light was unrivalled.
In the beginning, the accent was on the greatest possible range and constant illumination. Whether electric or not, the first vehicles travelled, more or less, with permanent high-beams. For this reason, even today in Germany, the terminal designation is 56a, compared with the later allocated terminal 56b for dipped headlights (1915). As the number of nocturnal motorists rose, the dipped-lights for the reduction of glare became necessary. Two separate dipped headlights were added, until in 1924 they were integrated into the high beam headlights.
In the beginning there were variable reflector systems and/or a reduced brightness of the light-source. Together with the now established electric light, the 2-element light bulb was already invented in 1924, of course in America, where the motorisation was increasing a hundred times stronger than in Europe. However, this light reached its breakthrough only when it became more similar to todays low-beam, state-of-technology light-bulb, with a dipped headlights cover. The lower part of the reflector was completely usable, even when the parking-lights were moved outwards and into a separate casing.
The decisive point was only reached in 1957, when the light-diffusing glas was changed in such a way that the kerb side of the road was more illuminated. Because of the unequal light distribution the system was called asymmetrical. Only much later was the effect made possible by the appropriate creation of the varying-stage reflector.Apart from the latest developments, e.g., with xenon light, only the development of the electric light bulb is worth mentioning. Various other gas fillings, higher pressures, and above all, higher temperatures of the glowing-element led to distinctly improved results. Occasionally these new lamps even influenced the design of the vehicles, because in the beginning they were not available as 2-element lamps (Bilux). In this case there were, once again, more four-headlight systems, exactly as it was with the first xenon generation.