Abstract:The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.
References:1. Neonsee, Application Note, The burning glass effect optical hot spot characterization for the automotive industry, 2011, 1. 2. Sivak M, Schoettle B, Flannagan MJ Mercury-free HID lamps: glare and colour rendering. Light Res Technol, 2006, Vol. 38, #1, pp. 33–40. 3. Jang S, Shin WS Thermal analysis of LED arrays for automotive head lamp with a novel cooling system. IEEE Trans Dev Mater Reliab, 2008, 8, #3, pp. 561–564. 4. Kasten, F. and Young, A.T., Revised optical air mass tables and approximation formula. Applied Optics, 1989, #28, pp. 4735–4738. 5. Fischer, P., “Radiative Heat Redistribution and Natural Convection Flow Inside an Automotive Fog Lamp”, Proceedings of the Sixth International Symposium on Automotive Lighting, Darmstadt, Germany, 2001. 6. https://www.plastics.covestro.com/~/media/Product%20Center/PCS/Images/5_Library/ Product%20brochures/Apec/Apec%20brochure. pdf?la=en&force=1 7. B. v. Blanckenhagen, Accurate Stray Light Simulations with the Bi- Directional Reflection Distribution Function, ISAL, 2005, p.39.
- sun load
- automotive lighting
- hot spot
- burning glass
- Computational Fluid Dynamics (CFD) Thermal Analysis