External lighting system. Purpose and principle of operation

10.8.1 External lighting systems

The main purpose of the outdoor lighting system is to provide the driver with the opportunity to drive the car at night, to emphasize himself on the road, and to warn other road users about any maneuvers - whether while changing direction, braking or changing lanes. The external lighting system includes headlights with low and high beam lamps. The block of a headlight of head lighting also contains addition lamps of indicators of turns, tail lamps. Depending on a complete set - lamps of additional illumination while turning (the example of a headlight lamp is given in figure 10.11) are installed additionally.

10.8.2 Headlights

Figure 10.11 Example of head lighting lamp.

There are a huge number of different design solutions and types of headlights. On the one hand, the design was simplified, and on the other – it became more complicated and more expensive. But the essence of the device has always been to convert the light of the lamp 20-30 watts into a powerful light flux, which is sufficient to illuminate the roadway at a fairly large distance. For this purpose, reflectors of the special form that are capable to collect and direct a stream of light from a lamp in the necessary direction and with the required power are used. Options with the installation of a condenser lens are also possible.

Note
Probably everyone as a child burned various drawings on a wood with a help of magnifying glass. In order to do this, the temperature must be high enough, but this is not the point. The light, falling on the magnifying glass, is amplified many times (depending on the characteristics of the lens) and is focused at a certain distance. And in the case of the reflector inside the headlight: it has a curved surface, which resembles the surface of a normal lens. And in the center of this reflector there is a lamp.

Interesting
At this stage of technology development, reflectors can have a rather complex shape for the most efficient amplification and direction of lamp light.

Nowadays, halogen lamps or gas-discharge tubes of main and low beam are used in headlights.

Note
Headlights are designed for collecting and amplifying light from lamps for better road lighting.

It is also worth mentioning that now LED headlights with LEDs are becoming more common. This technology is quite expensive, thus at the moment it is used only on fairly expensive cars.

10.8.3 Lantern combinations

We figured out the lighting system of the front part of the car. Combinations of lamps are installed on the rear part. An example of an arrangement of such a combination is shown in Figure 10.12.

Figure 10.12 Example of tail light.

Note
Combination of taillights, unlike headlights, must scatter the light of the lamps so that drivers of passing vehicles can clearly see the car ahead and are not blinded.

10.8.4 Fog lights

Perhaps everyone at least once in his life drove a car in the fog. A special "fun" was caused by a very thick and dense fog closer to the evening, which often makes you just stop and wait until visibility is recovered. And what if you have to drive anyway? In order to do this, fog lights were included in the outdoor lighting system. They are simpler than headlights, but have the same power and are installed below the level of the main headlights. This is done for one simple reason: in case if you turn on the headlights in the fog, the light from the headlights, which is reflected from the myriad particles of water (actually, the main composition of the fog), will create literally a white veil a few meters in front of the car through. You will not see anything at all, not even speaking of the road. And fog lights due to lower installation and powerful reflectors will kind of break through a fog layer, lighting the road.