Method for improving emulsion characteristics of engine oils

A method selected from:

• (a) a method for improving the ability of an engine lubricating oil contaminated with water and fuel to emulsify water contamination by using as the engine lubricating oil a formulated oil comprising a lubricating oil base stock as a major component and a coupled block copolymer as a minor component;
• wherein the coupled block copolymer comprises:
• an “A” block of a functionalized hydrocarbon moiety including one or more functional end groups derived from:
• epoxides, amines, acids, acid chlorides, acid anhydrides, halogens, vinyl or vinylidene double bonds, aromatic rings or thiols;
• and
• a “B” block of a functionalized polyether moiety including one or more functional end groups derived from:
• epoxides, amines, acids, acid chlorides, acid anhydrides, halogens, vinyl or vinylidene double bonds, aromatic rings or thiols;
• wherein the end group of the polyether moiety is different than the end group of the hydrocarbon moiety, and the hydrocarbon moiety and the polyether moiety are copolymerizable therewith;
• and
• wherein, in an engine lubricated with said lubricating oil, the ability of the engine lubricating oil contaminated with water and fuel to emulsify water contamination is improved as compared to the ability of an engine lubricating oil contaminated with water and fuel to emulsify water contamination using a lubricating oil containing a minor component other than the coupled block copolymer;
• and
• (b) a method for improving thermo-oxidative stability and elastomer compatibility in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil comprising a lubricating oil base stock as a major component and a coupled block copolymer as a minor component;
• wherein the coupled block copolymer comprises:
• an “A” block of a functionalized hydrocarbon moiety including one or more functional end groups derived from:
• epoxides, amines, acids, acid chlorides, acid anhydrides, halogens, vinyl or vinylidene double bonds, aromatic rings or thiols;
• and
• a “B” block of a functionalized polyether moiety including one or more functional end groups derived from:
• epoxides, amines, acids, acid chlorides, acid anhydrides, halogens, vinyl or vinylidene double bonds, aromatic rings or thiols;
• wherein the end group of the polyether moiety is different than the end group of the hydrocarbon moiety, and the hydrocarbon moiety and the polyether moiety are copolymerizable therewith;
• and
• wherein, in an engine lubricated with said lubricating oil, thermo-oxidative stability and elastomer compatibility are improved as compared to thermo-oxidative stability and elastomer compatibility achieved using a lubricating oil containing a minor component other than the coupled block copolymer.