Design
Design
Headlamp system, Bi-Xenon
Bi-Xenon uses gas discharge technology and is a headlamp system with moving reflectors. The system combines high and low beams in the same bulb.
It is a statutory requirement (for low beam) for vehicles with this type of bulb to be equipped with headlamps with automatic level control.
Xenon versus Halogen
Xenon:
- has higher color temperature which gives a whiter light
- reflects from road signs and markings better
- has lower power consumption. (approximately 2/3).
Worth knowing:
- Daylight has a color temperature of approximately 5000°K. The nearer to natural light, the easier the light is on the eye. Normal H4 bulb: approximately 3200 °K. Volvos gas discharge lamp (GDL): approximately 4200 °K
- The Bi-Xenon system also has the advantage of the high and low beam having the same color light. The human eye finds it easier to react between changes.
Bulb
The light source consists of a discharge pipe surrounded by glass which filters out damaging UV radiation.
- The discharge tube is filled with a number of chemical compounds including the noble gas Xenon
- A light arc is created by an electrical discharge between two tungsten electrodes
- Because the bulb does not have a filament it is less susceptible to bumps and vibration
- Bulb designation: D2R (special for reflector system).
- Power consumption: 35 W.
Caution! The bulb contains mercury (less than 0.5 mg) and when discarded must be treated as hazardous waste. Hazardous waste must be handled according to the relevant statutory regulations, see also Volvo Car Corporation's "Waste Management Guidelines for Dealers".
Ballast
An electronic ballast is connected to each headlamp. The ballast functions as a voltage regulator and generates alternative current (AC).
Main tasks:
1. Light the bulb
2. Control the light during operation.
To light the bulb an initial voltage of approximately 24, 000 V is required for a very short time (less than 1ms).
The ballast transforms the vehicles 12 V (DC) to 1000 V (AC).
The high tension switch amplifies the voltage a further 25 times.
When the lamp is lit the voltage is reduced to the 100 V required to keep the lamp lit.
Power consumption: 10 W.