Low conductivity lubricating oils for electric and hybrid vehicles

Abstract

Provided is a lubricating oil for electric and hybrid vehicles. The lubricating oil includes at least 80 wt % of a lubricating base oil, 0.5 to 5 wt % of one or more dispersants, 0 to 4 wt % of one or more neutral metal detergents, 0 to 1.5 wt % of zinc dialkyldithiophosphate, 0 to 0.2 wt % of molybdenum dialkyldithiocarbamate, 0 to 2 wt % of an active viscosity modifier, and 0.01 to 5 wt % of one or more other lubricating oil additives. The lubricating oil is essentially free of overbased metal detergents. The lubricating oil has an electrical conductivity from 50 to 3,000 pS/m and a kinematic viscosity from 2 to 20 cSt at 100° C. This disclosure also relates to methods for producing the lubricating oil, methods for lubricating electric and hybrid vehicles, and methods for controlling electrical conductivity of a lubricating oil by using conductivity promoters and conductivity inhibitors.

1 . A lubricating oil for use in electric or hybrid vehicles comprising:
 at least about 80 weight percent of a lubricating base oil, from about 0.5 to about 5 weight percent of one or more dispersants, from about 0 to about 4 weight percent of one or more neutral metal detergents, from about 0 to about 1.5 weight percent of zinc dialkyldithiophosphate (ZDDP), from about 0 to about 0.2 weight percent of molybdenum dialkyldithiocarbamate (MoDTC), from about 0 to about 2 weight percent of an active viscosity modifier, and from about 0.01 to about 5 weight percent of one or more other lubricating oil additives,   wherein the lubricating oil is essentially free of overbased metal detergents, and   wherein the lubricating oil has an electrical conductivity of from about 50 pS/m to about 3,000 pS/m, and a kinematic viscosity of from about 2 cSt to about 20 cSt at 100° C.   
     
     
         2 . The lubricating oil of  claim 1  wherein the lubricating base oil comprises a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, a Group V base stock, or mixtures thereof. 
     
     
         3 . The lubricating oil of  claim 1  wherein the one or more neutral metal detergents are selected from the group consisting of neutral metal salicylates, neutral metal alkylsulfonates, neutral calcium salicylates, neutral calcium alkylsulfonates, neutral magnesium alkylsulfonates, neutral metal-boron salicylates, neutral metal-boron alkylsulfonates, or mixtures thereof. 
     
     
         4 . The lubricating oil of  claim 1  wherein the lubricating oil is essentially free of neutral metal detergents. 
     
     
         5 . The lubricating oil of  claim 1  wherein the one or more dispersants are selected from the group consisting of borated dispersants, non-borated dispersants, and mixtures thereof. 
     
     
         6 . The lubricating oil of  claim 1  wherein the zinc dialkyldithiophosphate is present in an amount of from about 0.5 to about 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m. 
     
     
         7 . The lubricating oil of  claim 1  wherein the one or more of dispersants are present in an amount of from about 0.5 to about 2 weight percent, and the lubricating oil is essentially free of zinc dialkyldithiophosphate (ZDDP) and molybdenum dialkyldithiocarbamate (MoDTC), and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m 
     
     
         8 . The lubricating oil of  claim 1  wherein the one or more of dispersants are present from about 0.5 to about 3.5 weight percent, and the zinc dialkyldithiophosphate (ZDDP) is present from about 0.5 to 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 1,000 pS/m. 
     
     
         9 . The lubricating oil of  claim 1  wherein the lubricating oil is essentially free of the one or more neutral metal detergents, the zinc dialkyldithiophosphate (ZDDP) and the molybdenum dialkyldithiocarbamate (MoDTC). 
     
     
         10 . The lubricating oil of  claim 1  wherein the one or more dispersants is a non-borated, uncapped PIB succinimide dispersant. 
     
     
         11 . The lubricating oil of  claim 1  wherein the zinc dialkyldithiophosphate is a secondary zinc dialkyldithiophosphate. 
     
     
         12 . The lubricating oil of  claim 1  wherein the active viscosity modifier is selected from the group consisting of a linear or star-shaped polymer, a polymer or copolymer of methacrylate, butadiene, an olefin, or a styrene, and mixtures thereof. 
     
     
         13 . The lubricating oil of  claim 1  wherein the electric or hybrid vehicle has an electric vehicle powertrain including one or more of an electric motor, an electric drive motor, a 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. 
     
     
         14 . A method for lubricating electric or hybrid vehicles comprising:
 providing to one or more components of the electric or hybrid vehicle powertrain a lubricating oil comprising at least about 80 weight percent of a lubricating base oil, from about 0.5 to about 5 weight percent of one or more dispersants, from about 0 to about 4 weight percent of one or more neutral metal detergents, from about 0 to about 1.5 weight percent of zinc dialkyldithiophosphate (ZDDP), from about 0 to about 0.2 weight percent of molybdenum dialkyldithiocarbamate (MoDTC), from about 0 to about 2 weight percent of an active viscosity modifier, and from about 0.01 to about 5 weight percent of one or more other lubricating oil additives,   wherein the lubricating oil is essentially free of overbased metal detergents, and   wherein the lubricating oil has an electrical conductivity of from about 50 pS/m to about 3,000 pS/m, and a kinematic viscosity of from about 2 cSt to about 20 cSt at 100° C.   
     
     
         15 . The method of  claim 14  wherein the lubricating base oil comprises a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, a Group V base stock, or mixtures thereof. 
     
     
         16 . The method of  claim 14  wherein the one or more neutral metal detergents are selected from the group consisting of neutral metal salicylates, neutral metal alkylsulfonates, neutral calcium salicylates, neutral calcium alkylsulfonates, neutral magnesium alkylsulfonates, neutral metal-boron salicylates, neutral metal-boron alkylsulfonates, or mixtures thereof. 
     
     
         17 . The method of  claim 14  wherein the lubricating oil is essentially free of neutral metal detergents. 
     
     
         18 . The method of  claim 14  wherein the one or more dispersants are selected from the group consisting of borated dispersants, non-borated dispersants, and mixtures thereof. 
     
     
         19 . The method of  claim 14  wherein the zinc dialkyldithiophosphate is present in an amount of from about 0.5 to about 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m. 
     
     
         20 . The method of  claim 14  wherein the one or more of dispersants are present in an amount of from about 0.5 to about 2 weight percent, and the lubricating oil is essentially free of zinc dialkyldithiophosphate (ZDDP) and molybdenum dialkyldithiocarbamate (MoDTC), and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m 
     
     
         21 . The method of  claim 14  wherein the one or more of dispersants are present from about 0.5 to about 3.5 weight percent, and the zinc dialkyldithiophosphate (ZDDP) is present from about 0.5 to 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 1,000 pS/m. 
     
     
         22 . The method of  claim 14  wherein the lubricating oil is essentially free of the one or more neutral metal detergents, the zinc dialkyldithiophosphate (ZDDP) and the molybdenum dialkyldithiocarbamate (MoDTC). 
     
     
         23 . The method of  claim 14  wherein the one or more dispersants is a non-borated, uncapped PIB succinimide dispersant. 
     
     
         24 . The method of  claim 14  wherein the zinc dialkyldithiophosphate is a secondary zinc dialkyldithiophosphate. 
     
     
         25 . The method of  claim 14  wherein the active viscosity modifier is selected from the group consisting of a linear or star-shaped polymer, a polymer or copolymer of methacrylate, butadiene, an olefin, or a styrene, and mixtures thereof. 
     
     
         26 . The method of  claim 14  wherein the one or more components of the electric or hybrid vehicle powertrain include one or more of an electric motor, an electric drive motor, a 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. 
     
     
         27 . A method of producing a lubricating oil for use in electric or hybrid vehicles comprising:
 providing at least about 80 weight percent of a lubricating base oil, from about 0.5 to about 5 weight percent of one or more dispersants, from about 0 to about 4 weight percent of one or more neutral metal detergents, from about 0 to about 1.5 weight percent of zinc dialkyldithiophosphate (ZDDP), from about 0 to about 0.2 weight percent of molybdenum dialkyldithiocarbamate (MoDTC), from about 0 to about 2 weight percent of an active viscosity modifier, and from about 0.01 to about 5 weight percent of one or more other lubricating oil additives, and   blending the lubricating base oil, the one or more dispersants, the one or more neutral metal detergents, the zinc dialkyldithiophosphate, the molybdenum dialkyldithiocarbamate, the active viscosity modifier and the one or more other lubricating oil additives to produce the lubricating oil,   wherein the lubricating oil is essentially free of overbased metal detergents, and   wherein the lubricating oil has an electrical conductivity of from about 50 pS/m to about 3,000 pS/m, and a kinematic viscosity of from about 2 cSt to about 20 cSt at 100° C.   
     
     
         28 . The method of  claim 27  wherein the lubricating base oil comprises a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, a Group V base stock, or mixtures thereof. 
     
     
         29 . The method of  claim 27  wherein the one or more neutral metal detergents are selected from the group consisting of neutral metal salicylates, neutral metal alkylsulfonates, neutral calcium salicylates, neutral calcium alkylsulfonates, neutral magnesium alkylsulfonates, neutral metal-boron salicylates, neutral metal-boron alkylsulfonates, or mixtures thereof. 
     
     
         30 . The method of  claim 27  wherein the lubricating oil is essentially free of neutral metal detergents. 
     
     
         31 . The method of  claim 27  wherein the one or more dispersants are selected from the group consisting of borated dispersants, non-borated dispersants, and mixtures thereof. 
     
     
         32 . The method of  claim 27  wherein the zinc dialkyldithiophosphate is present in an amount of from about 0.5 to about 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m. 
     
     
         33 . The method of  claim 27  wherein the one or more of dispersants are present in an amount of from about 0.5 to about 2 weight percent, and the lubricating oil is essentially free of zinc dialkyldithiophosphate (ZDDP) and molybdenum dialkyldithiocarbamate (MoDTC), and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 2,000 pS/m 
     
     
         34 . The method of  claim 27  wherein the one or more of dispersants are present from about 0.5 to about 3.5 weight percent, and the zinc dialkyldithiophosphate (ZDDP) is present from about 0.5 to 1.5 weight percent, and wherein the lubricating oil has electrical conductivity of from about 50 pS/m to about 1,000 pS/m. 
     
     
         35 . The method of  claim 27  wherein the lubricating oil is essentially free of the one or more neutral metal detergents, the zinc dialkyldithiophosphate (ZDDP) and the molybdenum dialkyldithiocarbamate (MoDTC). 
     
     
         36 . The method of  claim 27  wherein the one or more dispersants is a non-borated, uncapped PIB succinimide dispersant. 
     
     
         37 . The method of  claim 27  wherein the zinc dialkyldithiophosphate is a secondary zinc dialkyldithiophosphate. 
     
     
         38 . The method of  claim 27  wherein the active viscosity modifier is selected from the group consisting of a linear or star-shaped polymer, a polymer or copolymer of methacrylate, butadiene, an olefin, or a styrene, and mixtures thereof. 
     
     
         39 . The method of  claim 27  wherein the electric or hybrid vehicle has an electric vehicle powertrain including one or more of an electric motor, an electric drive motor, a 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.