V50 L5-2.4L VIN 38 B5244S4 (2006)
discharge lamp (GDL) module are integrated into a single unit.
The main tasks of the ballast are:
1. Light the bulb.
2. Regulate light during operation.
A initial voltage of about 24,000 V for a very brief period (less than 1 ms) is required to light the bulb.
The ballast transforms the vehicle's 12 V (DC) to 1000 V (AC).
The high voltage contact amplifies the voltage an addition 25 times. Once the bulb has been lit, voltage is regulated down to about 100 V, which is
required to keep the bulb lit.
Power consumption: 10 W.
Bi-Xenon lamp
The light source consists of a discharge tube surrounded by a glass that filters out harmful UV radiation.
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The discharge tube is filled with a blend of chemical compounds, including the inert gas Xenon.
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An electric arch is created through an electrical discharge between two tungsten electrodes.
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Because the lamp does not have a filament, it is less sensitive to bumps and vibrations.
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Bulb designation: D2S (special for projector modules).
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Power consumption: 35 W.
CAUTION: The bulb contains mercury (less than 0.5 mg), thus classifying it as hazardous waste. Hazardous waste must be handled in
accordance with national legislation.
Xenon vs. Halogen.
Xenon:
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higher color temperature, which produces a whiter light
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better reflection of road signs and road markings
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has lower power consumption (about 2/3).
Good to know:
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Daylight has a color temperature of about 5000 degree K. The closer to natural light, the more restful the light is to the eyes. A standard H4 bulb
has a color temperature of about 3200 degree K. The Volvo gas discharge bulb has a color temperature of about 4200 degree K.
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With the Bi-Xenon system, high and low beam generates the same light color. The human eye thus has an easier time adjusting to switches
between high and low beam.
Design
Headlights
WARNING: The ballast, which is located in the wheel arch liner, and the wiring for the Bi-Xenon lamps are high voltage.
The headlights are operated via the light switch module (LSM). This is on the dashboard at the side of the steering wheel. The light switch module
(LSM) is directly connected to the central electronic module (CEM). Low and high beam are operated by moving the left control stalk toward the
steering wheel. In the Bi-Xenon lamps, an actuator motor (solenoid) is used to move a cover in front of the lamp in the lamp housing in order to switch
between high and low beam.
In cars with Bi-Xenon lamps, the lamps are powered directly via the central electronic module (CEM) without pulse width modulation.
To detect problems with the low beam, the central electronic module (CEM) reads the power consumption of the circuit. If this falls below a certain
