Oil composition for lubricating an EGR equipped diesel engine and an EGR equipped diesel engine comprising same

摘要

The present invention is directed to a lubricating oil composition, a diesel engine comprising a lubricating oil composition, and a method of lubricating a diesel engine provided with an exhaust gas recirculation system, comprising lubricating said engine with a lubricating oil composition comprising an oil of lubricating viscosity, and a polymeric N-dispersant booster comprising monomer units of:a) 0 to 40 wt. % of one or more ethylenically unsaturated ester compounds of formula (I); wherein R is equal to H or CH₃, R¹ represents a linear or branched alkyl group with 1 to 5 carbon atoms, R² and R³ independently represent H or a group of the formula —COOR′, wherein R′ is H or an alkyl group with 1 to 5 carbon atoms, b) 10 to 98 wt. % of one or more ethylenically unsaturated ester compounds of formula (II) ; wherein R is equal to H or CH₃, R⁴ represents a linear or branched alkyl group with 6 to 15 carbon atoms, R⁵ and R⁶ independently represent H or a group of the formula —COOR″, wherein R″ is H or an alkyl group with 6 to 15 carbon atoms, c) 0 to 30 wt. % of one or more ethylenically unsaturated ester compounds of formula (III) ; wherein R is equal to H or CH₃, R⁷ represents a linear or branched alkyl group with 16 to 30 carbon atoms, R⁸ and R⁹ independently represent H or a group of the formula —COOR′″, wherein R′″ is H or an alkyl group with 16 to 30 carbon atoms, d) 0 to 30 wt. % vinyl monomers,e) 7 to 25 wt. % of at least one N— dispersant monomer, wherein a)-e) add up to 100 wt. %.