On the Thermal Behavior of Automotive Headlamps in Battery Electric Vehicles – An Experimental Study

Automotive headlamps are subjected to diverse environmental conditions during their operation. Factors such as solar load, engine, ambient conditions, and lighting features affect the temperature of the headlamps. Several failure modes related to condensation and thermal management are considered during the design of the lamps. It involves an extensive application of numerical simulation tools based on computational fluid dynamics (CFD). In modelling the CFD boundary conditions, there is a need to adequately capture the effect of the various headlamp operating conditions especially for a Battery Electric Vehicle (BEV). In this work, we focused upon parking and charging conditions of a BEV. The temperature at different locations on headlamp lens and housing was measured across different test scenarios. We noticed that the temperature distribution was noticeably different across different lighting features and during charging. We observed hotspots on the lens close to the low beam and high beam modules when the corresponding features were in operation. Overall, the high beam led to significantly higher temperatures compared to other features. Additionally, we saw that the lamp temperature noticeably changed with the vehicle's orientation relative to the sun. The lens of the lamp facing the sun was marginally hotter compared to the lamp facing away from it. During charging, the headlamp temperature varied significantly even when turned off. This variation can be attributed to heat sources near the headlamp housing that are active during charging. This study uncovers the headlamp temperature variation across different operating conditions. It highlights the need to consider factors such as lighting features, vehicle orientation, charging conditions, and neighboring heat sources in modelling the temperature boundary conditions for the CFD simulations of headlamps.