## 4 Results and Discussion
Potential feasible ways include strengthening the heat dissipation of the whole LED lamp, adopting additional feedback circuits to ensure stable luminous output, and enhancing the thermal management of the entire headlight module for blocking the heat from the engine room and dissipating the heat from the LED lamp. Table 4 lists the temperature and temperature differences of each point of the LED lamp under different experimental conditions. Overall, the temperature of each point increased with \(T_{a}\). In addition, the rising rate of the temperature of the measurement point farther away from the LED chipsets was more affected by increasing the \(T_{a}\). In other words, \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Deg.**} & \multirow{2}{*}{\(T_{a}\)} & \multicolumn{6}{c}{**Low Beam**} & \multicolumn{6}{c}{**High Beam**} \\ \cline{3-13}  & & & **Illuminance** & \multicolumn{2}{c}{**Power Consumption**} & \multicolumn{2}{c}{**LEF**} & \multicolumn{2}{c}{**Illuminance**} & \multicolumn{2}{c}{**Power Consumption**} & \multicolumn{2}{c}{**LEF**} \\ \cline{3-13}  & & **lx** & **PD\%** & **W** & **PD\%** & **lx/W** & **PD\%** & **lx** & **PD\%** & **W** & **PD\%** & **lx/W** & **PD\%** \\ \hline \multirow{4}{*}{0} & 30 & 2795.0 & — & 13.71 & — & 203.8 & — & 3226.7 & — & 14.30 & — & 225.6 & — \\  & 40 & 2695.0 & \(-\)3.6 & 12.72 & \(-\)7.2 & 211.8 & 3.9 & 2961.7 & \(-\)8.2 & 13.20 & \(-\)7.7 & 224.4 & \(-\)0.5 \\  & 50 & 2511.7 & \(-\)10.1 & 11.59 & \(-\)15.5 & 216.8 & 6.4 & 2566.7 & \(-\)20.5 & 12.12 & \(-\)15.2 & 211.7 & \(-\)6.2 \\  & 60 & 2356.7 & \(-\)15.7 & 10.74 & \(-\)21.7 & 219.5 & 7.7 & 24483.3 & \(-\)24.1 & 11.09 & \(-\)22.5 & 220.8 & \(-\)2.1 \\ \hline \multirow{4}{*}{90} & 30 & 276.3 & — & 13.65 & — & 20.2 & — & 215.0 & — & 14.39 & — & 14.9 & — \\  & 40 & 265.7 & \(-\)3.9 & 12.66 & \(-\)7.3 & 21.0 & 3.7 & 197.5 & \(-\)8.1 & 13.13 & \(-\)8.8 & 15.0 & 0.7 \\  & 50 & 240.2 & \(-\)13.1 & 11.68 & \(-\)14.4 & 20.6 & 1.6 & 184.2 & \(-\)14.3 & 12.06 & \(-\)16.2 & 15.3 & 2.2 \\  & 60 & 235.2 & \(-\)14.9 & 10.76 & \(-\)21.2 & 21.9 & 8.0 & 171.8 & \(-\)20.1 & 11.15 & \(-\)22.5 & 15.4 & 3.2 \\ \hline \multirow{4}{*}{180} & 30 & 2318.3 & — & 13.65 & — & 169.9 & — & 2980.0 & — & 14.18 & — & 210.2 & — \\  & 40 & 2101.7 & \(-\)9.3 & 12.69 & \(-\)7.0 & 165.6 & \(-\)2.5 & 2843.3 & \(-\)4.6 & 13.01 & \(-\)8.2 & 218.5 & 4.0 \\ \cline{1-1}  & 50 & 2001.7 & \(-\)13.7 & 11.64 & \(-\)14.7 & 172.0 & 1.2 & 2656.7 & \(-\)10.9 & 12.12 & \(-\)14.5 & 219.2 & 4.3 \\ \cline{1-1}  & 60 & 1873.3 & \(-\)19.2 & 10.73 & \(-\)21.3 & 174.5 & 2.7 & 2355.0 & \(-\)21.0 & 11.11 & \(-\)21.6 & 212.0 & 0.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Illuminance, power consumption, and lighting efficiency of the LED lamp. the \(T_{a}\) has the least influence on the temperature of the substrate of the LED chipsets (\(T_{1}\)) but has the greatest influence on the aluminum fin radiator (\(T_{3}\)). This phenomenon is primarily because the effective contact area between the substrate of the LED chipsets and the surrounding ambient air was small. The heat dissipation of the substrate of the LED chipsets was mainly through the aluminum body to the aluminum fin radiator and then to the surrounding air. The heat transfer of the LED lamp to the surrounding ambient air mainly relied on the aluminum fin radiator with a high specific surface area. Therefore, the temperature of the aluminum fin radiator is most significantly affected by \(T_{a}\). Under the same experimental condition, the temperature difference between \(T_{3}\) and \(T_{a}\) was the largest, indicating that the thermal resistance between the aluminum fin radiator and the surrounding air is the largest. The second large temperature difference was between \(T_{1}\) and \(T_{2}\) because there was large thermal resistance between the substrate of the LED chipsets and the aluminum body.