Patent ID: 8012919
Filing Date: 2011-09-06
Classification: C10M,C10N

Abstract:
1. A method of operating a diesel engine provided with an exhaust gas recirculation system comprising lubricating said engine with a lubricating oil composition comprising: a lubricating oil composition comprising: (i) a polymeric 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 CH 3 , R R b) 10 to 98 wt. % of one or more ethylenically unsaturated ester compounds of formula (II) wherein R is equal to H or CH 3 , R R c) 0 to 30 wt. % of one or more ethylenically unsaturated ester compounds of formula (III) wherein R is equal to H or CH 3 , R R d) 0 to 30 wt. % of vinyl monomers, e) 7 to 25 wt. % of at least two N-dispersant monomers comprising: i) N-vinylpyrrolidinone, in amounts of up to 5 wt. %; and ii) at least one N-dispersant monomer one selected from the group consisting of dimethylaminopropylacrylamide, dimethylaminoethylacrylamide and tert-butyl aminoethylmethacrylate. wherein a)-e) add up to 100 wt.-%; and (ii) an oil of lubricating viscosity.