Lubricating and cooling fluid for an electric motor system
AssigneesAfton Chemical Corporation, Mercedes-Benz Group AG
InventorsRamnath Iyer, Christian Windel, Jörg Meyer-Berge
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Abstract
A lubricating and cooling fluid for an electric motor system including a lubricating base oil, at least one sulfurized component, a dispersant system comprising at least two dispersants, and a friction modifier system comprising at least two friction modifiers. The lubricating and cooling fluid provides good wear and friction performance as well as good copper corrosion and electrical conductivity for use in electric motor system.
Claims39
A method for lubricating gears and clutches in an electric motor system, wherein the electric motor system comprises a sump, copper windings in a stator, gears and clutches, and simultaneously cooling a motor thereof, the method comprising:
- operating an electric motor system, containing a lubricating and cooling fluid, such that a temperature of the lubricating and cooling fluid in a sump of the electric motor system is between 70° C. and 125° C. and the temperature of copper windings in a stator of the electric motor system is between 150° C. and 180° C.;
- lubricating gears and clutches in the electric motor system with the lubricating and cooling fluid and simultaneously cooling the motor in the electric motor system by contacting the copper windings with the lubricating and cooling fluid;
- and
- wherein the lubricating and cooling fluid comprises:
- an oil of lubricating viscosity comprises an API Group III base oil, API Group IV base oil, or mixtures thereof;
- at least one thiadiazole or hydrocarbyl-substituted derivatives thereof delivering about 1000 to about 1500 ppm sulfur to the lubricating and cooling fluid;
- a dispersant system including comprising (1) a first dispersant obtained from polyisobutylene having a number average molecular weight of about 1500 to about 2500 and delivering up to about 700 ppm nitrogen to the lubricating and cooling fluid and (i1) a second dispersant having a number average molecular weight of about 1000 or less and delivering up to about 150 ppm nitrogen to the lubricating and cooling fluid;
- an alkoxylated aliphatic amine delivering up to about 20 ppm nitrogen to the lubricating and cooling fluid;
- an ether amine delivering up to about 20 ppm nitrogen to the lubricating and cooling fluid;
- and
- wherein at least one of the first dispersant and the second dispersant is borated and phosphorylated such that a total amount of boron and phosphorus in the dispersant system relative to the nitrogen in the dispersant system is from about 0.5 to about 0.7 and wherein the first and second dispersants deliver up to about 100 ppm of total boron and phosphorus per 1000 number average molecular weight of the combined polyisobutylene moieties used in the dispersant system. first and second dispersants deliver up to about 100 ppm of total boron and phosphorus per 1000 number average molecular weight of the combined polyisobutylene moieties used in the dispersant system.
A lubricating and cooling fluid for an electric motor system , wherein the electric motor system comprises a sump, copper windings in a stator, gears and clutches, the lubricating and cooling fluid comprising:
- a majority base oil of lubricating viscosity comprising an API Group III base oil, an API Group IV base oil, or mixtures thereof;
- at least one thiadiazole or hydrocarbyl-substituted derivatives thereof delivering about 1000 to about 1500 ppm sulfur to the lubricating and cooling fluid;
- a dispersant system comprising (i) a first dispersant obtained from polyisobutylene having a number average molecular weight of about 1500 to about 2500 and delivering nitrogen in amounts of about 700 ppm or less nitrogen to the lubricating and cooling fluid and (ii) a second dispersant obtained from polyisobutylene having a number average molecular weight of about 1000 or less and delivering nitrogen in amounts of about 150 ppm or less nitrogen to the lubricating and cooling fluid;
- an alkoxylated aliphatic amine delivering up to about 20 ppm nitrogen to the lubricating and cooling fluid;
- an ether amine delivering up to about 20 ppm nitrogen to the lubricating and cooling fluid;
- wherein at least one of the first dispersant and the second dispersant is borated and phosphorylated such that a total amount of boron and phosphorus in the dispersant system relative to the nitrogen in the dispersant system is from about 0.5 to about 0.7 and wherein the first and second dispersants deliver up to about 100 ppm of total boron and phosphorus per 1000 number average molecular weight of the combined polyisobutylene moieties used in the dispersant system;
- wherein the lubricating and cooling fluid has an electrical conductivity of 60 nS/M or less, as measured by ASTM D2624-15 at 20 Hz and at 100° C.
Dependencies are inferred from the claim text.