Experimental study of highly alkaline motor oils in express diagnostics by drop test method

Abstract

Abstract In order to maintain the reliability and durability of the internal combustion engine during the operation of machines, systematic and operational monitoring of the state and level of technical fluids is necessary, where the most informative indicator is the change in the state of motor oils. The drop test method has been used for express diagnostics of motor oil for many years. Grades of oils with high base number, which are mainly used for high-speed internal combustion engines when diagnosing the state of these oils using the drop test on the surface of the filter used for analysis (Blue Tape filter paper), do not form zones in the form of rings, the change in diameter of which allows evaluating the operational properties of the operating motor oil. The study established that when analyzing the preservation of the properties of strongly alkaline motor oils (assessment of the contamination coefficient, dispersing properties), a spot of dirty oil is formed on the chromotogram of filter paper thus showing the filter structure. Theoretical studies revealed that the segregation into zones during the analysis of motor oils with strongly base number does not occur due to the action of electrical forces leading to the repulsion of contaminant particles. Electrical forces arise due to changes in molecules and alkali when a drop of oil flows through the surface of the filter, this interaction continues, and therefore, to analyze strongly alkaline motor oils, the base number must be neutralized, and a correction factor for the neutralizer must be introduced. The paper presents the results of experimental studies to determine the effective neutralizer of the alkalinity of a working motor oil in the process of diagnosing oil by the drop test, which made it possible to obtain concentric zones on the surface of filter paper to calculate the dispersing ability and other estimated oil indicators.