EGR EQUIPPED DIESEL ENGINES AND LUBRICATING OIL COMPOSITIONS

摘要

Soot induced kinematic viscosity increase of lubricating oil compositions fo r heavy duty diesel engines equipped with EGR systems operating in a condensin g mode can be ameliorated by selection of viscosity modifier, lubricating oil flow improvers, detergents and dispersants. The engine is lubricated with a lubricating oil composition comprising a major amount of oil of lubricating viscosity, and a minor amoun t of one or more high molecular weight polymers comprising (i) copolymers of hydrogenated poly(monovinyl aromatic hydrocarbon) and poly (conjugated diene), wherein th e hydrogenated poly(monovinyl aromatic hydrocarbon) segment comprises at least about 20 wt.% of the copolymer; (ii) olefin copolymers containing alkyl or aryl amine, or amide groups, nitrogen-containing heterocyclic groups or ester linkages or (iii) acrylate or alkylacrylate copolymer derivatives having dispersing groups.