Patent ID: 7923420

Claim:
A lubricating oil composition having a total base number of at least 15 mg KOH/g, as determined by ASTM D2896, the composition including: at least 40 mass % of an oil of lubricating viscosity; at least one overbased metal detergent; and at least one compound of formula (III): wherein each Ar′ independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, acyloxyalkoxy, aryloxy, aryloxyalkyl, aryloxyalkoxy, halo and combinations thereof; each L′ is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y′ is independently a moiety of the formula ZO— or Z(O(CR 2 2 ) n′ ) y′ X′—, wherein X′ is selected from the group consisting of (CR 2′ 2 ) z , O and S; R 2 and R 2′ are each independently selected from H, C 1 to C 6 alkyl and aryl; z′ is 1 to 10; n′ is 0 to 10 when X′ is (CR 2′ 2 ) Z′ , and 2 to 10 when X′ is O or S; y′ is 1 to 30; Z is H, an acyl group, a polyacyl group, a lactone ester group, an acid ester group, an alkyl group or an aryl group; wherein one or more Y′ are groups Z(O(CR 2 2 ) n′ ) y′ X′— in which Z is derived from lactone ester of formula IV, acid ester of formula V, bisacyl of formula VI or a combination thereof; wherein R 3 , R 4 , R 5 , R 6 R 7 , R 8 and R 9 are independently selected from H, alkyl and polyalkyl and polyalkenyl containing up to 200 C; R 10 and R 11 are independently selected from H, alkyl and polyalkyl and polyalkenyl containing up to 300 C; from about 2% to about 98% of the Y′ units are Z(O(CR 2 2 ) 2 ) y′ O—, wherein Z is an acyl group and y′ is 1 to 6, and from about 98% to 2% of Y′ units are —OR 2 ; m′ is 0 to 100; and p and s are each independently about 0 to about 25, with the proviso that p<m′; s<m′; and p+s>1.