Performance Parameters for Multi-Filament Halogen Lamps 2008-01-0487

In recent years new development has focused on LED and HID systems. However, halogen light sources still dominate the automotive market and continue to provide the most cost effective solutions. In order to reduce complexity and cost of lighting systems the desire is to combine multiple functions into one light source. Traditionally this was limited to dual filament halogen bulbs providing low and high beam functions. New developments in the halogen technology are resulting in the combination of other functions as well, such as DRL. While there are many advantages to the integration of multiple filaments into one source, it also introduces limits to their operation. Existing and new multiple filament sources with different filament power combinations are analyzed, especially in regards to simultaneous filament operation and their thermal loading. Depending on the filament power combination and their typical duty cycle different effects involving the halogen cycle and material properties become dominant. Effects in existing dual filament bulbs (H13), and new light sources, such as the H15 and a new prototype for a halogen adaptive forward lighting system (AFS) are discussed.