Research results of makeup influence on semi-synthetic motor oils thermal oxidation stability

During the running motor oil quality determination oil makeup has a big influence on thermal oxidation mechanism, however there is a problem of insufficient examination of makeup influence on motor oil conditions. Main goal of these researches is to determine how makeup effects on motor oil's thermal oxidation stability. For the research Lube oil Lukoil Super 10W - 40 SG/CD has been chosen. Thermal oxidation stability results assessment was conducted basing on obtained values of: light stream absorption criteria, volatility and thermal oxidation stability criteria in cases of research with makeup and without it. There was offered a criteria of makeup influence on thermal oxidation stability values, which identified as change of light stream absorption rate proportion and thermal oxidation stability criteria in case of research with and without makeup. Research methodology involved motor oil test on thermostating device consequently under temperatures 180, 170 and 160 °C with makeup and without it in condition when quantity of makeup oil corresponded to vaporized oil quantity. Research results demonstrated that oil makeup decrease thermal oxidation intensity on the whole temperature test rate.