Abstract: To address the issue that soot generated from the combustion of new engine fuels exhibits stronger "inertness" and that traditional soot dispersants have insufficient performance,a muti-naphthalene-ring polyisobutylene succinimide ashless soot dispersant,designated T166,was developed using 2-naphthol,vinylene carbonate,2-methoxynaphthalene,and formaldehyde as raw materials. Its structure was characterized ang its performance was evaluated.Structural characterization results confirmed that the synthesis successfully achieved the formation of 2-(2-naphthoxy)ethanol and its multicomponent copolymerization with 2-methoxynaphthalene,and formaldehyde,and that the resulting multicomponent copolymer was successfully grafted onto the polyisobutylene succinis anhydride (PIBSA) molecular backbone,yielding a noval soot dispersant containing multiple naphthalene rings,dydroxyl groups,ether bonds,and other functional groups on the molecular backbone. Performance evaluation results of the synthesized soot dispersant show that it possesses excellent soot dispersion capability.Its dispersion index in a CF-415W-40 formulated diesel engine oil is improved by more than 161% compared to the T161 dispersant.When added to a CI-4 15W-40 formulated diesel engine oil, the viscosity increase rate of the oil after oxidation testing is reduced by more than 43% relative to the oil containing the T161 dispersant. Furthermore,the synthesized dispersant outperforms a CK-4 15W-40 engine oil that has passed the Mack T-11 engine test in terms of soot dispersancy,antioxidant property,detergency,and shear stability,indicating that the the synthesized soot dispersant possesses well-rounded comprehensive performance.

Key words: naphthalene-rich, soot, dispersant, viscosity increase rate, diesel engine oil, Mack T-11 engine test