Lubricating oil compositions for electric vehicle powertrains

Abstract

This disclosure relates to a lubricating oil for an electric vehicle powertrain and powertrain components. The lubricating oil has a composition including a lubricating base oil as a major component, an additive package, as a minor component, and an effective amount of one or more conductivity agents, as a minor component. The lubricating oil has an electrical conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, with a ratio of electrical conductivity-to-dielectric constant from about 5 to about 10,000. This disclosure also relates to methods for producing a lubricating oil for an electric vehicle powertrain and powertrain components.

1 . A lubricating oil for an electric vehicle powertrain, said lubricating oil having a composition comprising: a lubricating base oil as a major component; an additive package, as a minor component, comprising one or more lubricating oil additives; and an effective amount of one or more conductivity agents as a minor component, wherein the lubricating oil has an electrical conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, and a ratio of electrical conductivity-to-dielectric constant from about 5 to about 10,000. 
     
     
         2 . The lubricating oil of  claim 1  wherein the lubricating oil has a ratio of electrical conductivity-to-dielectric constant from about 5 to less than 1,000. 
     
     
         3 . The lubricating oil of  claim 1  wherein the lubricating oil has a ratio of electrical conductivity-to-dielectric constant from about 1,000 to about 10,000. 
     
     
         4 . The lubricating oil of  claim 1  wherein the lubricating oil has an electrical conductivity from about 200 pS/m to about 16,000 pS/m. 
     
     
         5 . The lubricating oil of  claim 1  wherein the lubricating oil has a dielectrical constant from about 1.8 to about 3.5. 
     
     
         6 . The lubricating oil of  claim 1  wherein the lubricating oil has a kinematic viscosity from about 2 cSt to about 20 cSt at 100° C., a total acid number (TAN) less than about 3, less than about 200 ppm active sulfur, and a viscosity index (VI) greater than about 50. 
     
     
         7 . The lubricating oil of  claim 1  wherein the lubricating oil has a kinematic viscosity from about 2 cSt to about 14 cSt at 100° C., a total acid number (TAN) less than about 2, less than about 100 ppm active sulfur, and a viscosity index (VI) greater than about 100. 
     
     
         8 . The lubricating oil of  claim 1  wherein the lubricating base oil comprises a Group I, Group II, Group III, Group IV, Group V base stock, or mixtures thereof. 
     
     
         9 . The lubricating oil of  claim 1  wherein the lubricating base oil comprises: a blend of a Group IV base stock and a Group V base stock; a blend of a Group III base stock and a Group V base stock; a blend of a Group II base stock and a Group V base stock; or a blend of a Group I base stock and a Group V base stock. 
     
     
         10 . The lubricating oil of  claim 1  wherein the lubricating base oil comprises: a blend of a PAO base stock and an alkylated naphthalene or ester base stock; a blend of a GTL base stock and an alkylated naphthalene or ester base stock; or a blend of a Group II base stock and an alkylated naphthalene or ester base stock. 
     
     
         11 . The lubricating oil of  claim 1  wherein the lubricating base oil comprises a blend of a PAO base stock having a kinematic viscosity of about 3 cSt to about 250 cSt at 100° C., and an alkylated naphthalene or ester base stock having a kinematic viscosity of about 2 cSt to about 22 cSt at 100° C.; wherein the lubricating oil has a kinematic viscosity from about 4 cSt to about 12 cSt at 100° C. 
     
     
         12 . The lubricating oil of  claim 11  wherein the PAO base oil is present in an amount from about 5 to about 95 weight percent of the lubricating oil, and the alkylated naphthalene or ester base oil is present in an amount from about 5 to about 95 weight percent of the lubricating oil. 
     
     
         13 . The lubricating oil of  claim 1  wherein the lubricating base oil is present in an amount of from about 70 weight percent to about 95 weight percent, based on the total weight of the lubricating oil. 
     
     
         14 . The lubricating oil of  claim 1  wherein the additive package is present in an amount of from about 0.01 to about 30 percent, based on the total weight of the lubricating oil. 
     
     
         15 . The lubricating oil of  claim 1  wherein the additive package comprises one or more lubricating oil additives selected from the group consisting of an antioxidant; a detergent; a dispersant; an antiwear agent; a corrosion inhibitor; a viscosity modifier; a metal passivator; a pour point depressant; a seal compatibility agent; an antifoam agent, an extreme pressure agent; a friction modifier; and mixtures thereof. 
     
     
         16 . The lubricating oil of  claim 1  wherein the one or more conductivity agents are present in an amount of from about 0.01 to about 30 weight percent, based on the total weight of the lubricating oil. 
     
     
         17 . The lubricating oil of  claim 1  wherein the one or more conductivity agents are selected from the group consisting of ionic liquids, phospholipids, fatty acids, dispersants, detergents, antiwear agents, polar basestock fluids, and mixtures thereof. 
     
     
         18 . The lubricating oil of  claim 1  further including a dielectric agent. 
     
     
         19 . The lubricating oil of  claim 18  wherein the dielectric agent comprises a polar basestock fluid in an amount sufficient to increase the dielectric constant by about 0.02 or more. 
     
     
         20 . The lubricating oil of  claim 17  wherein the ionic liquids are present in an amount of from about 0.01 to about 10 weight percent. 
     
     
         21 . The lubricating oil of  claim 17  wherein the ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium dicyanamide, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate, tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate, 1-methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide, and tetradecylammonium bis(2-ethylhexyl) phosphate. 
     
     
         22 . The lubricating oil of  claim 17  wherein the phospholipid is L-α-phosphatidylcholine or lecithin. 
     
     
         23 . The lubricating oil of  claim 17  wherein the fatty acid is stearic acid. 
     
     
         24 . The lubricating oil of  claim 17  wherein the dispersant is selected from the group consisting of ashless alkyl succinimides, metal-modified alkyl succinimides, and mixtures thereof. 
     
     
         25 . The lubricating oil of  claim 24  wherein the metal of the metal-modified alkyl succinimides dispersant comprises zinc, boron, or mixtures thereof. 
     
     
         26 . The lubricating oil of  claim 17  wherein the detergent is selected from the group consisting of metal alkyl salicylates, metal alkyl sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates, low-base calcium alkyl salicylate, high-base calcium alkyl salicylate, neutral calcium alkyl sulfonates, and mixtures thereof. 
     
     
         27 . The lubricating oil of  claim 17  wherein the antiwear agent is zinc dialkyl dithiophosphate. 
     
     
         28 . The lubricating oil of  claim 17  wherein the polar basestock fluid is diethylhexyl azelate diester. 
     
     
         29 . The lubricating oil of  claim 1  wherein the electric vehicle powertrain is one or more of an electric motor, an electric drive motor, a transmission, a front axle, a rear axle, a gear box, a differential, gears, bearings, a battery, a capacitor, a generator, an alternator, a converter, a kinetic energy accumulator, or a kinetic energy recovery system. 
     
     
         30 . A method for producing a lubricating oil for an electric vehicle powertrain, said method comprising:
 providing at least one lubricating oil basestock as a major component;   providing at least one additive package as a minor component comprising one or more lubricating oil additives;   providing an effective amount of at least one conductivity agent as a minor component; and   blending the at least one lubricating oil basestock, and the at least one additive package, and the at least one conductivity agent to produce the lubricating oil;   wherein the lubricating oil has an electrical conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, and a ratio of electrical conductivity-to-dielectric constant from about 5 to about 10,000.   
     
     
         31 . The method of  claim 30  wherein the lubricating oil has a ratio of electrical conductivity-to-dielectric constant from about 5 to less than 1,000. 
     
     
         32 . The method of  claim 30  wherein the lubricating oil has a ratio of electrical conductivity-to-dielectric constant from about 1,000 to about 10,000. 
     
     
         33 . The method of  claim 30  wherein the lubricating oil has an electrical conductivity from about 200 pS/m to about 16,000 pS/m. 
     
     
         34 . The method of  claim 30  wherein the lubricating oil has a dielectrical constant from about 1.8 to about 3.5. 
     
     
         35 . The method of  claim 30  wherein the lubricating oil has a kinematic viscosity from about 2 cSt to about 20 cSt at 100° C., a total acid number (TAN) less than about 3, less than about 200 ppm active sulfur, and a viscosity index (VI) greater than about 50. 
     
     
         36 . The method of  claim 30  wherein the lubricating oil has a kinematic viscosity from about 2 cSt to about 14 cSt at 100° C., a total acid number (TAN) less than about 2, less than about 100 ppm active sulfur, and a viscosity index (VI) greater than about 100. 
     
     
         37 . The method of  claim 30  wherein the lubricating base oil comprises a Group I, Group II, Group III, Group IV, Group V base stock, or mixtures thereof. 
     
     
         38 . The method of  claim 30  wherein the lubricating base oil comprises: a blend of a Group IV base stock and a Group V base stock; a blend of a Group III base stock and a Group V base stock; a blend of a Group II base stock and a Group V base stock; or a blend of a Group I base stock and a Group V base stock. 
     
     
         39 . The method of  claim 30  wherein the lubricating base oil comprises: a blend of a PAO base stock and an alkylated naphthalene or ester base stock; a blend of a GTL base stock and an alkylated naphthalene or ester base stock; and a blend of a Group II base stock and an alkylated naphthalene or ester base stock; a blend of a Group II base stock and an alkylated naphthalene or ester base stock; a blend of a Group III base stock and an alkylated naphthalene or ester base stock. 
     
     
         40 . The method of  claim 30  wherein the lubricating base oil comprises a blend of a PAO base stock having a kinematic viscosity of about 4 cSt to about 250 cSt at 100° C., and an alkylated naphthalene or ester base stock having a kinematic viscosity of about 2 cSt to about 22 cSt at 100° C.; wherein the lubricating oil has a kinematic viscosity from about 4 cSt to about 12 cSt at 100° C. 
     
     
         41 . The method of  claim 40  wherein the PAO base oil is present in an amount from about 5 to about 95 weight percent of the lubricating oil, and the alkylated naphthalene or ester base oil is present in an amount from about 5 to about 95 weight percent of the lubricating oil. 
     
     
         42 . The method of  claim 30  wherein the lubricating base oil is present in an amount of from about 70 weight percent to about 95 weight percent, based on the total weight of the lubricating oil. 
     
     
         43 . The method of  claim 30  wherein the additive package is present in an amount of from about 0.01 to about 30 percent, based on the total weight of the lubricating oil. 
     
     
         44 . The method of  claim 30  wherein the additive package comprises one or more lubricating oil additives selected from the group consisting of an antioxidant; a detergent; a dispersant; an antiwear agent; a corrosion inhibitor; a viscosity modifier; a metal passivator; pour point depressant; a seal compatibility agent; an antifoam agent, an extreme pressure agent; a friction modifier; and mixtures thereof. 
     
     
         45 . The method of  claim 30  wherein the one or more conductivity agents are present in an amount of from about 0.01 to about 30 weight percent, based on the total weight of the lubricating oil. 
     
     
         46 . The method of  claim 30  wherein the one or more conductivity agents are selected from the group consisting of ionic liquids, phospholipids, fatty acids, dispersants, detergents, antiwear agents, polar basestock fluids, and mixtures thereof. 
     
     
         47 . The method of  claim 30  further including a dielectric agent. 
     
     
         48 . The method of  claim 47  wherein the dielectric agent comprises a polar basestock fluid in an amount sufficient to increase the dielectric constant by about 0.02 or more. 
     
     
         49 . The method of  claim 46  wherein the ionic liquids are present in an amount of from about 0.01 to about 10 weight percent. 
     
     
         50 . The method of  claim 46  wherein the ionic liquids are selected from the group consisting of 1-ethyl-3-methylimidazolium dicyanamide, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate, tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate, 1-methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide, and tetradecylammonium bis(2-ethylhexyl) phosphate. 
     
     
         51 . The method of  claim 46  wherein the phospholipid is L-α-phosphatidylcholine or lecithin. 
     
     
         52 . The method of  claim 46  wherein the fatty acid is stearic acid. 
     
     
         53 . The method of  claim 46  wherein the dispersant is selected from the group consisting of ashless alkyl succinimides, metal-modified alkyl succinimides, and mixtures thereof. 
     
     
         54 . The method of  claim 53  wherein the metal of the metal-modified alkyl succinimides dispersant comprises zinc, boron, or mixtures thereof. 
     
     
         55 . The method of  claim 46  wherein the detergent is selected from the group consisting of metal alkyl salicylates, metal alkyl sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates, low-base calcium alkyl salicylate, high-base calcium alkyl salicylate, neutral calcium alkyl sulfonates, and mixtures thereof. 
     
     
         56 . The method of  claim 46  wherein the antiwear agent is zinc dialkyl dithiophosphate. 
     
     
         57 . The method of  claim 46  wherein the polar basestock fluid is diethylhexyl azelate diester. 
     
     
         58 . The method of  claim 30  wherein the electric vehicle powertrain is one or more of an electric motor, an electric drive motor, a transmission, a front axle, a rear axle, a gear box, a differential, gears, bearings, a battery, a capacitor, a generator, an alternator, a converter, a kinetic energy accumulator, or a kinetic energy recovery system.