Abstract: With the development of logistics industry and infrastructure industry, the requirements for heavy truck fuel economy are constantly improving. Four heavy duty diesel engine oils CI-4 15W-40, which meet the quality standards of GB/T 11122—2006, were prepared by using paraffin-based lubricating base oil produced by CNOOC (Taizhou) Petrochemical Co. Ltd. as raw materials, adding a certain amount of compound additives, viscosity index improvers, organic molybdenum friction improvers, polymer friction improvers. The effects of friction modifiers on physical and chemical properties, anti-wear and extreme pressure properties and driving performance of heavy duty diesel engine oil were mainly investigated. The results showed that it took time for the organic molybdenum friction modifier to display the effect at low temperature, and the polymer friction modifier could significantly improve the extreme pressure performance. There was a synergistic effect between the two friction modifiers, which could improve the fuel economy of vehicles by 1% - 2% in driving test.

Key words: diesel engine oil, friction improver, driving test, fuel economy