Graphical Automotive Electrical Technology 2 - Automotive Lighting System

First, the automotive lighting system overview

Automotive lighting systems are one of the must-have systems for safe driving. It mainly includes external lighting fixtures, interior lighting fixtures, external signal lamps, internal signal lamps and so on.

Automobile luminaires are divided according to their functions. There are two main types, namely, car lights and car lights.

Car lights can be divided into headlights, fog lights, license plate lights, instrument lights, ceiling lights, etc. according to their installation position and function.

Car lights include turn signals, hazard warning lights, width lights, tail lights, brake lights and backup lights.

Here we use the lamp as an example to introduce the car lighting system. Headlights, also known as headlights, are mounted on either side of the car's head for illumination of night-time roads. At present, the types of headlights commonly used in automobiles are halogen headlights, xenon headlights and LED headlights.

Second, halogen headlights

Although the gas filled bulb is filled with an inert gas, there is still a small amount of gaseous tungsten evaporated from the tungsten wire to blacken the bulb. In order to prevent evaporation of the tungsten halogen bulb, a tungsten halogen bulb has been invented in recent years. The so-called halogen bulb is a halogen element such as fluorine, chlorine, bromine or iodine mixed in the gas charged into the bulb. When the bulb is working, a tungsten halogen regeneration cycle can be formed inside: the gaseous tungsten evaporated from the tungsten filament reacts with the halogen element to form a volatile tungsten halide which diffuses to the high temperature region near the filament and is heated again. Decompose, so that the tungsten is returned to the filament.

The released halogen continues to participate in the next cycle of the reaction, so that it circulates repeatedly, thereby preventing the evaporation of the tungsten wire and the blackening of the bulb. The glass of the tungsten halogen bulb is made of high temperature resistant and high strength glass, and the inflation pressure in the bulb is large and the working temperature is high, which can more effectively suppress the evaporation of tungsten, prolong the service life of the bulb, and improve the luminous efficiency. At the same power, the brightness of the tungsten halogen bulb is 1.5 times that of the gas bulb, and the life of the halogen bulb is 2-3 times that of the gas bulb.

Third, Xenon headlights

1. Advantages of xenon headlamps

Xenon lamps are also called high-intensity arc lamps. These lamps do not have a conventional filament. Instead, they are two electrodes mounted in a quartz tube filled with helium and trace metals (or metal halides). The arc lamp consists of three parts: an arc lamp assembly, an electronic controller and a booster. Its light color is similar to that of fluorescent lamps. Its brightness is about 3 times that of current halogen bulbs, and its lifetime can reach 5 times that of halogen bulbs.

2. Xenon headlight dimming

On the xenon headlights, the low beam and the high beam share a light bulb, and switching between them is achieved by a visor (louver) that is controlled by an electromagnet. This visor is flipped up at the basic position, which is used to achieve asymmetric low beam, as shown in the following figure. To achieve the high beam function, the electromagnet needs to be energized (activated), so that the visor is turned down and the gas discharge lamp produces a symmetrical beam of high beam.