Antinoxidant sludge control additives

摘要

The invention relates to a process for mitigating NOx-induced sludge formation in engine oils by dissolving in an engine oil of lubricating viscosity an effective amount of a molecule having at least one head portion enriched in NOx reactive carbon-carbon unsaturation and at least one oil soluble hydrocarbyl, preferably aliphatic, tail portion having an absence of carbon-carbon unsaturation of suitable chain length in an optimum ratio of head to tail sufficient to reduce NOx-induced sludge formation in the engine oil. The invention also relates to formulated lube oil compositions containing the antinoxidant additive. The molecules include polyethylene propylene copolymer- and polyisobutylene-grafted hydroquinone polyalkylthiophenes, fullerene-grafted lube oil basestock, ethylene propylene polymer-grafted phenol and ethylene butylene polymer-grafted phenol.