Electrical Properties of Engine Oils—Comparison of Electrical Parameters with Physicochemical Characteristics

The increasing demand for the real-time monitoring of engine oil quality has driven the development of novel diagnostic methods. Traditional techniques primarily rely on physicochemical assessments, which, while effective, are often time consuming and require specialized laboratory equipment. This study explores the feasibility of using electrical property measurements to assess engine oil quality, offering a potential alternative for rapid, cost-effective diagnostics. A proprietary measurement system utilizing two innovative sensors—rectangular and concentric—was employed to evaluate the electrical characteristics of five commercially available synthetic engine oils. Key parameters, including impedance (|Z|), phase shift angle (θ), conductance (G), susceptance (B), parallel equivalent capacitance (Cp), and quality factor (Q), were measured across a frequency range of 100 Hz to 1.2 MHz. These results were correlated with conventional physicochemical parameters, specifically viscosity and infrared spectroscopy data, to determine the reliability and accuracy of electrical diagnostics in assessing oil degradation and quality variations. The findings indicate a correlation between selected electrical parameters and traditional laboratory measurements, particularly within the 1 kHz to 10 kHz frequency range, where the measurement repeatability was the highest. The study also identifies key challenges associated with sensor sensitivity to environmental factors and provides insights into optimizing the measurement process. The results contribute to the ongoing development of alternative, real-time oil condition monitoring techniques, potentially improving the reliability of automotive and industrial lubrication systems.