Electrical Parameters as Diagnostics of Fresh Engine Oil Condition-Correlation with Test Voltage Frequency

Artur Wolak; Ryszard Żywica; Jarosław Molenda; Joanna Katarzyna Banach

doi:10.3390/s23083981

Electrical Parameters as Diagnostics of Fresh Engine Oil Condition-Correlation with Test Voltage Frequency

Sensors (Basel). 2023 Apr 14;23(8):3981. doi: 10.3390/s23083981.

Authors

Artur Wolak¹, Ryszard Żywica², Jarosław Molenda³, Joanna Katarzyna Banach²

Affiliations

¹ Department of Quality and Safety of Industrial Products, Cracow University of Economics, Sienkiewicza 4 St., 30-033 Kraków, Poland.
² Institute of Management and Quality, Faculty of Economics, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland.
³ Łukasiewicz Research Network-Institute for Sustainable Technologies, 6/10 Pułaskiego St., 26-600 Radom, Poland.

Abstract

The aim of this study was to assess whether electrical parameters (capacitance and conductivity) of fresh engine oils-tested over a wide range of measurement voltage frequencies-can be used for oil quality assessment and its identification, based on physicochemical properties. The study encompassed 41 commercial engine oils with different quality ratings (American Petroleum Institute (API) and European Automobile Manufacturers' Association (ACEA)). As part of the study, the oils were tested for their total base number (TBN) and total acid number (TAN), as well as their electrical parameters, including impedance magnitude, phase shift angle, conductance, susceptance, capacitance and quality factor. Next, the results for all of the samples were examined for correlations between the mean electrical parameters and the test voltage frequency. A statistical analysis (k-means and agglomerative hierarchical clustering) was applied to group oils with similar readings, drawing on the values for all electrical parameters to produce group oils with the highest similarity to each other into clusters. The results show that the electrical-based diagnostics of fresh engine oils can serve as a highly selective method for identifying oil quality, offering much higher resolution than assessments based on the TBN or the TAN. This is further supported by the cluster analysis, with five clusters generated for electrical parameters of the oils, compared to only three generated for TAN- and TBN-based measurements. Out of all the tested electrical parameters, capacitance, impedance magnitude and quality factor were found to be the most promising for diagnostic purposes. The value of electrical parameters of fresh engine oils is mostly dependent on the test voltage frequency (with the exception of capacitance). The correlations identified in the course of the study can be used to select for those frequency ranges that offer the highest diagnostic utility.

Keywords: capacitance; conductance; electrical parameters; engine oil; impedance magnitude; phase shift angle; quality factor; susceptance; total acid number; total base number; voltage frequency.

Grants and funding

The publication was co-financed from the subsidy granted to the Cracow University of Economics, Project nr 068/ZJB/2022/POT. This work was supported by the Ministry of Science and Higher Education of Poland as part of statutory activities from: Faculty of Economics, University of Warmia and Mazury in Olsztyn, project No. 22.610.100-110.