Abstract: SM/GF-4 additive package and SM/GF-4 5W-30 gasoline engine oil formulation technology were developed by SINOPEC Research Institute of Petroleum Processing. The simulation tests and physical and chemical properties of the oil met all requirements of SM/GF-4 specifications. The dosage of the SM/GF-4 additive package was 7.5% (w). Through MTM and HFRR friction and wear tests, the anti-friction and low temperature anti-wear properties of the newly developed SM/GF-4 5W-30 oil were evaluated. Glycerol monoolete additive still had good friction reducing performance after aging. The piston deposit after sequence IIIG engine test, which evaluate the high temperature oxidation property of engine oil, was studied by X-ray photoelectron spectroscopy. The results showed that the piston deposits mainly contained sulphated ash of engine oil besides carbon deposit.

Key words: SM/GF-4 gasoline engine oil, additive package formulation, engine test