Study of Internal Spatial Temperature Distribution of Lubricating Oil Based on Transmission Spectroscopy

The temperature of lubricating oil plays a pivotal role in determining the performance of engines and other machinery, underscoring the importance of studying its temperature distribution for optimizing engine efficiency. In this study, a custom experimental setup was developed to measure the transmittance of lubricating oil across a wavelength range of 380 nm to 1040 nm at various temperatures. A novel method was proposed to compute the temperature distribution along the light path using transmission spectra. By formulating a mathematical model that correlates the temperature distribution with light intensity, the optical characteristics of lubricating oil undergoing a phase change at a single interface in low-temperature environments were thoroughly investigated. A comparative analysis between the experimentally measured temperatures and those obtained from temperature sensors revealed that the temperature distribution trends predicted by the proposed method closely aligned with the experimental data, exhibiting an average deviation of only 2.87 degrees C. These results demonstrate the robustness and accuracy of the method, validating its potential for reliable temperature distribution estimation in lubricating oil.