Steady State Thermal Approximation to Thermal Transients in Lighting Unit Design
Automotive lighting technology has a rough and hard journey in the past from candle to nowadays LEDs. Having high efficacy with LEDs, luminous flux decrease is a thermal management problem that should be handled with. Minimum luminous flux requirements are determined by specific regulations and in design phase, the limits of optical design of each function in lighting unit has to be exceeded. High optical requirement results with high thermal power that has to be considered and managed in design of lighting units. Thermal management of lighting device can be handled both with thermal transients and steady state numerical approximation procedures. Thermal transient management is time consuming task and not appropriate for numerical experimentation on design of lighting device. Because of several functions that has the device to satisfy with like signal, turn indicator and tail function. Each function has to be investigated in detail through standards. Instead of thermal transients defining local power constants enable the analyst to predict transient characteristic of the function clearly. In this study defining appropriate thermal power constants for the steady state approach in order to predict thermal transient characteristic of a lighting device is investigated. Numerical results with steady state approximation are compared with test results, and appropriate power constants identified.
Keywords - Thermal Power Constants, Automotive Lighting Unit Design, Steady-State Thermal Management of Lighting Device