Integrated Numerical and Experimental Study on the Thermal Management for LED Daytime Running Lamp

Abstract

The daytime running light (DRL) is a special lamp; they can be automatically switched on when the engine is started, and hence substantially increase the visibility of motor vehicles. Comparing to traditional light sources in DRL, LED offers many advantages such as its high lighting efficacy, low power consumption, quick response time, and long lifetime, However, the application of high brightness LED on DRL still faces severe thermal challenge in removing the unavoidable dissipation heat, which directly influences the radiation efficiency, emitted light quality, and lifetime of LED. Therefore, this investigation focuses on the thermal management for LED Daytime Running Lamp through an integrated effort of CFD simulation, CNC mockup fabrication, and experimental verification. At first, a comprehensive CFD simulation is executed to check the heat-removing performance of several thermal modules for identifying the efficient thermal design. Thereafter, this LED module integrated with a Zinc-Al alloy casing is fabricated via the die-casting and carried out the thermal performance measurements for experimentally validating the numerical outcomes. As a result, after taking the contact resistance and radiation into account, the comparison between numerical and experimental results indicates an acceptable deviation percentage within 5%. Also, experimental result shows that the LED junction temperature is located within the range of 50∼51°C for the case of a 2.34-Watt power input and a 35°C environmental temperature. Moreover, for a 10-Watt power input, the numerical calculation predicts that LED junction temperature is 88.6°C, which is still well below the safety limit (120°C). In conclusion, the accomplishment of this research offers a rigorous and systematic design scheme for the thermal management of the LED DRL. This design scheme has successfully produced an efficient thermal module to control the LED chip temperature below safety limit.