Lubricating fluid for an electric motor system
AssigneeAfton Chemical Corporation
InventorsRamnath Iyer, Lisa Thalen
Life of this patent
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Abstract
An electric motor driveline fluid for an electric motor system including a lubricating base oil, at least one sulfurized component, and at least one dispersant derived from a polyisobutylene having an average number molecular weight of at least 2000. The electric motor driveline fluid provides acceptable wear performance as well as good electrical conductivity and oxidative stability for use in electric motor system fluids having a low viscosity when select elemental relationships of phosphorus, sulfur, and calcium and included in the fluid.
Claims24
An electric driveline fluid comprising:
- one or more base oils of lubricating viscosity;
- a succinimide dispersant derived from a polyisobutylene having a number average molecular weight of about 2,000 or greater, wherein the succinimide dispersant has up to about 1 weight percent nitrogen and is post treated with a phosphorus containing compound and a boron containing compound, and wherein the succinimide dispersant delivers about 150 to about 270 ppm of dispersant phosphorus (P) to the electric driveline fluid;
- a sulfur-providing additive including a thiadiazole or derivative thereof, wherein the thiadiazole or derivative thereof provides at least about 1000 ppm of thiadiazole sulfur (S) to the electric driveline fluid;
- wherein the combined dispersant phosphorus and thiadiazole sulfur (P+S) is at least about 1300 ppm and wherein a weight ratio of the dispersant phosphorus to the thiadiazole sulfur (P/S) is at least about 0.1;
- a detergent system providing one or more calcium-containing detergents, and wherein the one or more calcium-containing detergents provide no more than about 200 ppm of calcium;
- no more than about 0.4 weight percent of friction modifier;
- and
- wherein the electric driveline fluid has a kV100 viscosity of about 3.2 cSt or more, about 150 to about 270 ppm of total phosphorus, and an electrical conductivity of about 130 nS/M or less as measured by a modified conductivity test pursuant to ASTM D2624-15 using the electric driveline fluid and measured at 20 Hz and at 170° C.
A method for lubricating a driveline component including an electric motor, the method comprising:
- lubricating the driveline component with an electric driveline fluid;
- the electric driveline fluid includes (i) one or more base oils of lubricating viscosity;
- (ii) a succinimide dispersant derived from a polyisobutylene having a number average molecular weight of about 2,000 or greater, wherein the succinimide dispersant has up to about 1 weight percent nitrogen and is post treated with a phosphorus containing compound and a boron containing compound, and wherein the succinimide dispersant delivers about 150 to about 270 ppm of dispersant phosphorus (P) to the electric driveline fluid;
- (iii) a sulfur-providing additive including a thiadiazole or derivative thereof providing at least about 1000 ppm of thiadiazole sulfur (S) to the electric driveline fluid, wherein the combined dispersant phosphorus and thiadiazole sulfur (P+S) is at least about 1300 ppm and wherein a weight ratio of the dispersant phosphorus to the thiadiazole sulfur (P/S) is at least about 0.1;
- (iv) a detergent system providing one or more calcium-containing detergents, wherein the one or more calcium-containing detergents provide no more than about 200 ppm of calcium;
- and (v) no more than about 0.4 weight percent of a friction modifier;
- and
- wherein the electric driveline fluid has a kV100 viscosity of about 3.2 cSt or more, about 150 to about 270 ppm of total phosphorus, and an electrical conductivity of about 130 nS/M or less as measured by a modified conductivity test pursuant to ASTM D2624-15 using the electric driveline fluid and measured at 20 Hz and at 170° C.
Dependencies are inferred from the claim text.