Oxidation Stable EV Transmission Fluids

Electric traction drive system with optimized cooling and lubrication for electric vehicles. The system has both active and passive cooling/lubrication circuits. In normal operation, an electric pump actively cools the electric machine. But if the pump fails or active cooling is not needed, a passive circuit takes over using oil pressure from the transmission components like gears and bearings. This ensures fail-safe lubrication and optimizes efficiency/thermal performance by using the right cooling circuit for each operating condition.

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Lubricating oil composition for electric vehicle transmissions that balances wear protection with good copper corrosion resistance, sufficient volume resistivity, and good hot surface deposit control. The composition contains a sulfur-based additive with a thiadiazole and a sulfurized polyolefin, along with phosphorus-containing anti-wear additives. The sulfur-based additive provides wear protection and helps prevent corrosion. The phosphorus additives provide wear protection without contributing to corrosion. The oil also has specific viscosity and volume resistivity ranges.

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Lubricating oil composition for electric vehicles, comprising a major amount of lubricating oil, a phosphorus-containing additive, and a sulfur-containing additive selected from thiadiazole, dithiadiazole, dimercaptodithiadiazole, and derivatives thereof, wherein the sulfur-containing additive is soluble in the lubricating oil without the need for a dispersant additive.

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A low-traction and high-pressure viscosity fluid formulation for electric vehicle drive units and drivelines that provides improved efficiency, gear protection, and motor cooling through optimized boundary and mixed lubrication regimes. The formulation combines low-friction molecules with higher-viscosity secondary molecules to achieve reduced friction and traction, while maintaining high-temperature stability and hydrolytic resistance.

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Melamine-based corrosion inhibitors for lubricants that provide improved copper corrosion protection compared to traditional tolyltriazole additives. The melamine derivatives are oil-soluble compounds formed by reacting hydrocarbyl-substituted succinic acids or anhydrides with melamine. The reaction involves using a molar excess of the succinic acid or anhydride relative to the melamine. The resulting melamine succinimide or acid/amide compounds have structures like Formula I. These melamine derivatives provide copper corrosion inhibition in lubricants like transmission fluids, axle fluids, and gears without the use of tolyltriazole.

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Base oil composition for electric vehicle fluids comprising a blend of poly-alpha-olefins (PAO) with different viscosities, and an electric vehicle fluid prepared using the base oil. The base oil is formulated by mixing PAO components with a viscosity range of 2-20 cSt, and the electric vehicle fluid is prepared by adding functional additives to the base oil under controlled temperature and mixing conditions. The base oil composition provides improved thermal conductivity, oxidation stability, and lubrication performance for electric vehicle applications.

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Lubricating oil compositions with enhanced fatigue protection, particularly suitable for functional fluids and electric vehicle applications, comprising 0.001-1.5% anti-fatigue additive and sulfonate detergent, with reduced levels of sulfur-containing compounds, such as metal sulfurized phenates, and optionally glycerol, which imparts improved fatigue performance without compromising anti-wear properties.

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A lubricant fluid for electric vehicle transmissions that combines biodegradable ester base oils with a carefully selected additive package to provide optimal performance in high-torque, high-speed, and low-temperature operating conditions. The fluid features a unique blend of ester base oils, including a high-viscosity complex ester, along with a specialized anti-foam additive and a friction modifier. The formulation is designed to meet the specific demands of electric vehicle transmissions, including low electrical conductivity to prevent dielectric breakdowns.

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Electric vehicle transmission fluid formulation that provides high performance under extreme pressure and high load conditions while maintaining compatibility with yellow metals and electrical components. The fluid formulation includes an oxidation inhibitor, anti-wear additive, and copper corrosion protection, and exhibits low electrical conductivity to prevent static electricity discharge. The formulation is designed to meet the unique demands of electric vehicle transmissions in both light and heavy duty applications.

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Lubricant composition for electric vehicle propulsion systems that improves antiwear and anticorrosion properties by combining triazole corrosion inhibitors with amine- and sulfur-based antiwear additives. The triazole compounds like tolyltriazole prevent corrosion of metal components while the amine-sulfur additives like dimercaptothiadiazoles reduce wear. This combination provides simultaneous wear and corrosion protection for electric vehicle motors, bearings, and transmissions.

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A lubricant composition for electric and hybrid vehicle motors, comprising a base oil blend of polyalkylene glycol (PAG), poly-alpha-olefin (PAO), and ester, with an additive package including a sulfur-based extreme pressure agent. The PAG provides thermal stability and low viscosity, while the PAO and ester enhance solubility and compatibility with the extreme pressure agent. The composition is optimized for electric motor applications, avoiding additives typically used in conventional lubricants that can degrade performance.

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Base oil for automotive transmission and gear systems that provides superior traction and thermal management properties in electric vehicles. The base oil comprises a unique blend of compounds optimized for electric vehicle powertrains, featuring improved oxidation stability, thermal conductivity, and viscosity characteristics. The formulation enables enhanced traction performance in electric vehicles, particularly in the high-temperature regions of the powertrain, while maintaining reliable low-friction operation in the low-temperature conditions of the battery pack and other components.

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A lubricating fluid for electric motor systems in hybrid and electric vehicles, comprising a lubricating oil and additives, including a succinimide dispersant, a sulfur-providing additive, and a detergent system, that provides improved wear protection, oxidative stability, and electrical conductivity while maintaining low viscosity. The fluid is formulated with a specific combination of additives that balance antiwear, friction, and corrosion performance while minimizing electrical conductivity.

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A lubricating fluid composition for electric drives that prevents corrosion of electrical components while maintaining high efficiency in transmissions. The composition comprises 10-88% by weight of a low-viscosity synthetic oil, 0.1-5% by weight of a borated succinimide dispersant, 0.1-5% by weight of a 2,5-alkyl-thiadiazole compound, and 0.1-5% by weight of a phosphorus-containing additive. The composition has a dynamic viscosity of 0.8-4.0 mm2/s at 100°C and is suitable for use in electric motors, transmissions, and battery-operated vehicles.

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When the electric motor (EM) of a hybrid electric vehicle (HEV) is located inside the transmission housing, the cooling performance and the electrical compatibility of the automatic transmission fluids (ATFs) play a more relevant role. These two features depend on both physicochemical and thermal properties of the lubricant, but these properties change with the aging or oxidation of the ATF. This work studies the influence of external factors like temperature, time, and air exposition on the oxidation of three commercial ATFs and how this oxidation affects properties such as density, viscosity, thermal conductivity, heat capacity, ionicity, and some cooling-related figures-of-merit (FOMs) of the fluids, and thus, their cooling performance and electrical compatibility. The results showed that the molecular structure of the ATFs has more influence on thermal conductivity and heat capacity than on density, and hardly affects the FOMs of the fresh lubricants. Those ATFs formulated with API Group III base oils resulted in better cooling properties than the ATF with base oils from API Grou... Read More

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Lubricating oil composition for transmissions that achieves both low viscosity and high gear protection while preventing copper corrosion and maintaining oxidation stability. The composition combines a sulfur-based extreme pressure agent with a phosphorus-based extreme pressure agent, both having specific molecular structures, to create a protective oil film on metal surfaces. This film suppresses metal-to-metal contact and solid phase fusion, preventing gear damage such as scuffing. The composition is suitable for use in transmissions where gear protection is critical, particularly in applications where low viscosity lubricants are required for fuel efficiency.

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A lubricant base stock with improved thermal stability and oxidation resistance, comprising a high viscosity Group II base stock with a kinematic viscosity at 100°C of 29 cSt to 32 cSt or more, and a sulfur content of less than 0.03 wt %. The base stock is produced by catalytic processing of C3 deasphalted oils, and exhibits superior performance in oxidation tests and haze formation resistance compared to conventional base stocks.

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Fluids for electric vehicles that have improved performance compared to traditional lubricants. The fluids contain base stocks with specific properties like high viscosity index, high saturates content, and low aromatics content. The base stocks are derived from deasphalted oil using processes like hydroprocessing and solvent extraction. This allows forming high viscosity Group II base stocks with lower pour points, better color, and equivalent viscosity index compared to Group I stocks. The fluids also have improved thermal conductivity and specific heat capacity for cooling electric machines and batteries.

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A lubricant base stock with improved thermal stability and oxidation resistance, comprising a high viscosity Group II base stock with a kinematic viscosity at 100°C of 29 cSt to 32 cSt or more, and a composition of greater than or equal to 90 wt % saturates, less than or equal to 10 wt % aromatics, and a sum of terminal/pendant propyl groups and terminal/pendant ethyl groups of at least 1.7 per 100 carbon atoms. The base stock is suitable for use in low-temperature environments and can be formulated into lubricants with enhanced deposit resistance and oxidation stability.

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A lubricating composition for electric and hybrid vehicles that combines lubrication and cooling properties. The composition comprises a base oil and additives such as antiwear, antioxidant, and dispersant agents, with specific concentration ranges of boron (≤100 ppm) and nitrogen (100-500 ppm). The composition is designed to provide improved durability and electrical resistivity for electric motor and hybrid vehicle applications, including cooling of power electronics, rotors, and stators, as well as lubrication of bearings and gearboxes.

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