Control Method of Thermo-oxidative Stability Factors of Synthetic Motor Oil

This article presents the results of the research on the effect of temperature on a number of thermo-oxidative stability factors, including optical density, volatility, thermo-oxidative stability index and potential resource. The method of researching lubricating oils for thermal-oxidative stability is described; it includes the application of testing devices and control, such as a device for thermostating the oils, photometer for direct electrophoretic oxidized oils and electronic scales. The authors investigate the dependences of optical density, potential resource, volatility and thermo-oxidative stability factors on the time and testing temperature of synthetic motor oil, on the basis of which new factors of thermo-oxidative stability were proposed including the temperatures of the onset of oxidation, volatility and temperature transformations in oil, and the critical temperatures of these processes. This article proposes a grapho-analytical model for the definition of thermo-oxidative stability factors at all temperatures without the research based on oil testing under two temperatures, which makes it possible to reduce the labour inputs of the research by more than two times. The proposed control method of thermo-oxidative stability factors allows the authors to expand the information on the quality of lubricants by determining the onset temperatures of oxidation, evaporation and temperature conversions in oil, as well as critical temperatures of these processes. It also allows improving the classification system by the groups of operational properties.