Development of Multi-DOF Model of Automotive LED Headlamp Assembly for Force Transmission Prediction Using MATLAB GUI

The use of Light-emitting diodes (LEDs) in automobile headlamps began two decades ago. Since then, several design and efficiency improvements have been made. However, the reliability and durability of these LED systems remain uncertain. There are several approaches for reliability analysis, e.g., thermal, electrical, optical, or structural. The first three issues have been studied in the past, but there has been minimal focus on structural and dynamic durability. Uneven road conditions and impact forces acting on the headlamp module can damage components and misalign the aiming mechanism. Moreover, the functionality could be disturbed, thereby decreasing the efficiency of the system. To determine the forces acting inside the module on each component, this study proposes a simulation technique for predicting the magnitude of forces transmitted from the automobile chassis to the headlamp module under even and uneven road conditions. A vibration system with 23 degrees-of-freedom is developed and equations of motion are derived using Newton’s second law of motion. Solving this system of equations with Simulink and MATLAB provided the linear and angular displacements of each element, which were then utilized to calculate the forces transmitted through these elements. Two forcing conditions were compared and the locations with maximum forces are highlighted.

Heat Radiation Effect of Passenger Car Headlamp Using Plate Heat Pipe

The existing heat pipe applied to a LED headlamp has a large size although it has only small area of contact. Therefore, it is difficult to achieve a harmonious radiation of heat along with the difficulty in attaching the LED due to its large volume. This study proposed a plate heat pipe to solve the aforementioned problems. Through the study, the effects of the thickness and acetone filling rate on the heat radiation effects of a plate heat pipe at room temperature and vehicle driving environment were confirmed along with comparison with the heat radiation effects of the existing copper heat pipe. The heat radiation effects were checked by attaching a thermocouple to the evaporator, adiabatic section and condenser of the LED. As the results of the experiment, it was found that a temperature below 120oC, which is the allowable temperature to guarantee the performance of the LED, is maintained. In addition, as the results of comparison of radiation of heat, it was confirmed that the plate heat pipe with a thickness of 2 mm and 20% filled with acetone has a better performance than the existing copper heat pipe.