Lubricating oil compositions for automatic transmissions
AssigneeChevron Japan Ltd.
InventorsKoichi KUBO, Masami FUCHI, Naoya SASAKI, Takahiro NAKAGAWA, Satoshi OHTA
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Abstract
The present invention generally relates to lubricating oil compositions useful for automatic transmissions, and particularly transmission oils for automotive automatic transmissions in battery electrical vehicles (BEVs), hybrid vehicles (HVs) and plug-in hybrid vehicles (PHVs). The lubricant is free of metal compounds (e.g., Ca, Mo, or Zn) and demonstrates high volume resistivity, wear protection, and copper corrosion resistance.
Claims18
A lubricating oil composition for battery electrical vehicles (BEVs), hybrid vehicles (HVs) and plug-in hybrid vehicles (PHVs) with electric motors and/or generators comprising:
- a. a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 20 mm2/s;
- b. a phosphorus antiwear additive selected from inorganic phosphorus acids, acidic or neutral phosphite esters, acidic or neutral phosphate esters and their amine salts, or combinations thereof;
- c. a nitrogen-based corrosion inhibitor, wherein the total amount of nitrogen provided by the corrosion inhibitor to the lubricating oil composition is no more than 125 ppm based of the weight of the lubricating oil composition;
- d. a sulfur EP additive, wherein the total amount of sulfur provided by the sulfur EP additive to the lubricating oil composition is 300 to 1500 ppm based of the weight of the lubricating oil composition,
- wherein the lubricating oil composition contains less than 50 ppm of metals and has a volume resistivity greater than 1.0×109 Ω·cm at 80° C.
A method of reducing corrosion and improving wear protection in the transmission systems of battery electrical vehicles (BEVs), hybrid vehicles (HVs) and plug-in hybrid vehicles (PHVs) with electric motors and/or generators comprising lubricating and operating said transmission system with a lubricating oil composition comprising:
- a. a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 20 mm2/s;
- b. a phosphorus antiwear additive selected from inorganic phosphorus acids, acidic or neutral phosphite esters, acidic or neutral phosphate esters and their amine salts, or combinations thereof;
- c. a nitrogen-based corrosion inhibitor, wherein the total amount of nitrogen provided by the corrosion inhibitor to the lubricating oil composition is no more than 125 ppm based of the weight of the lubricating oil composition;
- d. a sulfur EP additive, wherein the total amount of sulfur provided by the sulfur EP additive to the lubricating oil composition is 300 to 1500 ppm based of the weight of the lubricating oil composition,
- wherein the lubricating oil composition contains less than 50 ppm of metals and has a volume resistivity greater than 1.0×109 Ω·cm at 80° C.
Dependencies are inferred from the claim text.