Abstract: Taking coal based APIIII+ lube base oil from F-T synthesis as raw material, the initial oxidation temperature and high temperature deposit of the obtained formula oil were determined by high pressure differential scanning calorimeter (PDSC) and TEOST MHT-4 test device. The influences of complex agent and antioxidant on initial oxidation temperature and high temperature deposit of coal based base oil were studied. The results showed that the oxidation stability of base oil was not enhanced by the addition of complex agent and antioxidant. On the contrary, excessive antioxidant increased the formation of high temperature deposits due to its own oxidation. By testing the fully-formulated coal based gasoline engine oil, it could be seen that the initial oxidation temperature and the high temperature deposit were 259.94 ℃ and 18 mg, respectively. Compared with a certain brand of petroleum based 5W-30 gasoline engine oil, the coal based 5W-30 gasoline engine oil had better oxidation stability and lower high temperature deposit generation.

Key words: gasoline engine oil, TEOST MHT-4, PDSC, initial oxidation temperature, high temperature deposit