Thermally Stable Lubricants for EV

Abstract Electric vehicle (EV) technology has matured over time, improving in some performance areas against traditional internal combustion engine (ICE) vehicles. Despite advancement, there is considerable opportunities for further improvements, particularly in the broader field of lubrication, including areas like grease. As in any mechanical system, greases and lubricants play a significant role in the component life of EV power plants and drivetrains. Moreover, they can significantly contribute to vehicle efficiency, energy savings, and overall driving experience. Since the lubricants in EVs work under harsh thermal and electrical environments, designing an ideal high performance and stable lubricant can be challenging. This paper evaluates the industry's progress on EV lubrication including analyzing existing lithium-based lubricants and spotlighting advanced material additives such as graphene, boron nitride, or cutting-edge ionic liquids. It also discusses optimizing base stock selection, with a focus on Polyalphaolefin (PAO) molecules and designing various additives to enhanc... Read More

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A lubricating grease for high-performance tribological systems, particularly in automotive applications, that achieves low friction and wear properties without the use of perfluorinated compounds. The grease contains a combination of silicone oil and polyalphaolefin base oils, an overbased calcium sulfonate thickener, and a calcium carboxylate additive, which together provide excellent anti-wear and extreme pressure performance across a wide temperature range. The grease is also suitable for use in food-grade applications, meeting NSF/H1 standards, and is free from boric acid and its compounds.

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Heat transfer fluid for electric and hybrid vehicles comprising a neat ester base stock or ester blend as the primary component, with optional additives such as viscosity modifiers, pour point depressants, and dispersants to enhance performance characteristics. The ester base stock provides improved heat transfer properties compared to traditional fluids, enabling efficient cooling of high-temperature battery and power generation systems.

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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 lubricating fluid for electric motor systems in hybrid and electric vehicles, comprising a base oil of lubricating viscosity, a high molecular weight succinimide dispersant, an amine salt of a phosphoric acid ester, an ashless dialkyl dithiophosphate, and a sulfur-providing additive. The fluid has a kinematic viscosity of 4.5 cSt or less, 150-250 ppm total phosphorus, and an electrical conductivity of 37 nS/m or less. The succinimide dispersant is derived from a polyisobutylene with a number average molecular weight of 2000 or greater, and is post-treated with a phosphorus and boron containing compound.

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Functional fluid for electric vehicles comprising an ester selected from the group consisting of: esters obtainable from esterification of a saturated branched monoalcohol comprising from 5 to 16 carbon atoms, with isostearic acid; esters obtainable from esterification of 2-hexyl-1-decanol with a saturated fatty acid comprising from 7 to 18 carbon atoms; and mixtures thereof. The ester exhibits multiple properties such as lubricity, cooling, electric, and compatibility with elastomer(s), and suitable physico-chemical properties to be used in an electric vehicle.

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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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A method to prevent chemical degradation of hydrocarbon-based fluids at elevated temperatures, caused by nitrogen dioxide contamination, by adding a specific ionic liquid that deactivates nitrogen dioxide and inhibits nitration reactions. The ionic liquid, composed of a trihexyltetradecyl phosphonium cation and a hydroxybenzoate or salicylate anion, is added to the fluid in a concentration of 0.1-5.0% by weight before service at temperatures above 60°C.

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Solid lubricants are those materials that are used to lubricate mainly in dry circumstances. Its main role is similar to that of oils and greases, which is used to create a continuous and adherent lubricant film on the tribological pair surfaces for minimising friction and wear [1]. These coatings are typically employed in situations where liquid lubricants cannot be used or do not offer expected lubrication, such as in high or cryogenic temperatures, high vacuum, ultrahigh-radiation, reactive environments and in extreme contact pressure conditions [2]. Different types of solid lubricants, including graphite, have been extensively used since the middle of the 20th century [3]. From 1950 onwards, development in aeronautics industries emphasised the research and development of advanced solid lubricants. They can be classed based on their crystalline structure, features, properties, or functions, among other things. Different types of solid lubricant coating are shown in Fig. 1 [1].

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A lubricating oil composition for electric vehicle cooling systems, comprising a base oil and a fluorine compound, where the base oil is a mineral oil with a 40°C kinematic viscosity of 1-25 mm²/s, and the fluorine compound content is 3-30% by weight. The composition provides both lubricity and cooling performance, enabling efficient heat management in electric vehicle systems.

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Electric vehicle (EV) transmissions operate at high speeds. High-speed operation puts higher demands on bearings, seals, and gears. Bearings in EV transmissions are prone to electrically induced bearing damage and may exhibit signs of pitting and fluting. Surface-initiated rolling contact fatigue is another common problem gaining increased attention lately. Most EV transmissions require a coupling between an oil-lubricated gearbox to an electrical motor that runs with minimal lubrication at very high rpm. The high mechanical and thermal stresses the seals are exposed to under starved lubrication conditions have a detrimental impact on their service life. Hence, proper lubrication is critical. In general, EV transmission fluids call for a somewhat different spectrum of properties compared to conventional ATFs. Gear tribology simulations open new ways to the design and optimization of lubrication for EV transmissions. Additionally, such simulations can also provide valuable insights into the effects of different oil properties on cooling and lubrication efficiencies, thereby helping in... Read More

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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 transmission fluid composition for hybrid and fully electric vehicles that provides lubrication, cooling, and electrical insulation. The composition comprises a major amount of a lubricating oil basestock and a minor amount of an additive package containing a phosphorus-containing compound, a calcium salicylate detergent, and a non-calcium-salicylate detergent. The additive package enables the fluid to balance competing demands of electrical insulation, wear protection, and low viscosity, while also providing cooling and energy efficiency benefits.

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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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A lubricant fluid for electric vehicle transmissions that combines biodegradable ester base oils with a carefully selected additive package to achieve optimal performance in high-torque, low-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 specific anti-foam additive and a friction modifier. The formulation is designed to meet the unique demands of electric vehicle transmissions, including compatibility with high-voltage components and low electrical conductivity.

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Electric vehicles (EVs) have gained increased attention in recent years owing to their excellent performance and emission of less hazardous products to the surroundings. The varied design of EVs compared to the internal combustion engine vehicles has created new requirements in lubricants and fluids for their operation. The increasing electrification of vehicle drivetrains has led to lubricants being in contact with more electrical components, such as motors, sensors, battery modules, and power electronics. This has led to different operating conditions, such as being subjected to an electric field, higher rpm, and higher thermal stress, affecting the electrical properties of lubricants, especially for electrified transmission fluid. The electrical properties of lubricants play a vital role in preventing corona discharge and arc absorbance, which can cause premature failure and electromagnetic interference problems in motors, leading to bearing instability, excessive vibrations, and noise. Understanding the interactions of lubricants with the electric field is crucial for optimizing ... Read More

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To increase the driving range of electric vehicles (EVs) and to make them less dependent on fossil-based technology, it is important to switch to new types of lubricants with low friction and renewable origin. During the past couple of decades, researchers found that glycerol, which is biodegradable and nontoxic, can provide superlubricity even under high contact pressure with rough surfaces. Glycerol can also be used as a coolant for EVs to increase the efficiency of the electric motors. This chapter gives a summary of the tribological performance of different contacts, i.e., steel-steel, steel-diamond-like carbon (DLC), DLC-DLC, steel-self-lubricating materials, and steel-ceramic, which are lubricated by glycerol.

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When exposed to high surface temperatures, engine lubricating oils degrade and may form solid deposits, which cause operational issues and increase shutdown time and maintenance costs. Despite its being a common issue in engine operation, the information available on the mechanics of this phenomenon is still lacking, and the experimental data and conditions must be updated to match the improvements in both lubricant stability and engine efficiency. To this end, an experimental apparatus has been developed to study the mechanisms that lead to the degradation and deposit formation of lubricants at high temperatures. The apparatus is designed to operate at pressures up to 69 bar, surface temperatures up to 650 C, oil bulk temperatures up to 550 C, and flow rates of <14 mL/min. In this apparatus, the oil is cycled through a heated test section, and deposits accumulate on the heated surface. The time required for deposits to start accumulating under the test conditions is determined based on the recorded temperature traces, and collected oil and deposit samples may be analyzed to... Read More

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Abstract Aviation lubricating oil, as the blood of machine operation, plays an important role in the lubrication, cooling, cleaning, sealing, rust prevention, and other aspects of aeroengines, thereby ensuring the safe and stable longterm endurance of aeroengines under highspeed and hightemperature conditions. The thermal oxidation of aviation lubricating oil leading to decay is the most important factor causing lubricating oil failure, which will seriously affect the performance of aeroengines and endanger flight safety. Here, we comprehensively summarize the oxidation mechanism of aviation lubricating oil, factors affecting thermal oxidation of aviation lubricating oil, evaluation methods for thermal oxidation of aviation lubricating oil, and antioxidants that inhibit thermal oxidation of aviation lubricating oil. We hope that this review can enhance readers' understanding of the thermal oxidation of aviation lubricating oil, stimulate broader interest, and promote more exciting development in this promising field.

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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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The understanding of the lubrication properties under electrical conditions, in order to achieve the suppression of electrical damage and even use the electrical environment to promote lubrication, is highly relevant to the bearings used in electric cars. In this chapter, important research progress on lubrication as well as the premature failure of bearings under electrical conditions in the past decades will be briefly reviewed. The basic research on dry friction under electrical conditions and then the molecular adsorption and orientation at the lubricated interface under electrical conditions will be discussed. Subsequently, microbubble behaviors in thin lubrication films under electrical conditions will be introduced. The electrodamage in bearings under electrical conditions and the protection technology are discussed in the final part.

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As countries prioritize climate change concerns, promoting the use of new environmentally friendly working fluids has become a common goal for the industry. In thermal systems, lubricants come into contact with these working fluids and directly affect their utilization efficiency. Therefore, investigating the effect of lubricant mixing on the physical properties of process media is essential to promote the adoption of new environmentally friendly working fluids. This paper categorizes and organizes recent research literature on working fluids and lubricants. It was aimed to comprehend the effect of lubricants on the operating characteristics of working fluids. By comparing the research methods and experimental equipment utilized in previous studies, this work analyzes the variation of basic physical properties, including miscibility, solubility, viscosity, and gas-liquid phase equilibrium. In addition, the effects of lubricant mixing in terms of heat exchange characteristics, additives, and material compatibility are also summarized. These findings provide a reference for achieving o... Read More

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Rapid advances in modern industrial tribo-systems under high temperatures and heavy loads generate a growing demand for lubricating materials used in extreme environmental conditions. Metal-based lubricant coatings with excellent mechanical properties and thermal stability are widely used on core parts to reduce friction in harsh environments. This paper reviews the progress on modulating the frictional properties of coatings by designing the components and preparation techniques to prolong the lifetime of metal-based lubrication coatings. The impacts of the microstructural changes on the mechanical performances, including hardness, plasticity, interfacial adhesion, and environmental stability, were essential for the deformation and crack propagation of the coatings. Their performances and lubrication mechanisms were concerned under heavy loads, in a wide range of temperatures, and in corrosive marine environments. Finally, the study concluded the basic requirements of metal-based coatings for extreme environments at this stage. The research challenges and potential problems of metal... Read More

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Heat transfer fluids based on at least partly re-refined lubricating oils for use in various systems, including cooling systems for thermal or electric motors, refrigerators, boilers, air conditioners, and thermal solar collectors. The fluids are formulated using re-refined lubricating oils obtained from used lubricating compositions, which have been subjected to one or more re-refining treatment steps to eliminate contaminants. The re-refined oils are characterized by their composition and physicochemical properties, which are distinct from virgin base oils. The fluids can be used as a coolant in mobile or stationary motor systems, and can be formulated with additives to promote compatibility with system materials.

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The paper presents the results of studies aimed at defining the effect of the cooling properties of oil lubricants used in various metalworking processes. The design and a brief description of the installation are given, which allows to obtain temperature-time, temperature-velocity dependencies of various liquids. The use of this installation gives the opportunity to select lubricants according to its cooling properties, depending on the temperature range required by the process. The assessment results of lubricant cooling properties at UZS-2 installation, manufactured according to the requirements of international standards ISO 9950, ASTM D6200 - 01 and ASTM D6482 06 are presented. The dependences of tribo-engineering properties of the tested oil lubricants on their cooling characteristics are found out. It is shown that with an increase in the temperature at which the maximum cooling rate of the lubricant is provided, its extreme pressure and anti-wear properties determined according to GOST on a four-ball friction machine increase.

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The development of suitable fluids, including lubricants or coolants, for electric vehicles (EVs) requires large efforts on their formulation, characterization, and performance testing. An important property for these fluids is dielectric strength or breakdown voltage (BDV), which is expected to be as high as possible at wide temperature range. Short circuits and bearing currents are highly undesirable phenomena which are known to cause inefficiencies and potential failure or wear of electromechanical hardware if BDV magnitude is not adequate. In modern EVs, the typical fluids comprise lubricants (for bearings and gears in the driveline) such as automatic transmission fluids (ATFs) and low-viscosity gear oils, and coolants (for thermal management in the battery pack and power electronics), namely, ethylene-glycols and dielectric oils. Although these fluids are reported to have acceptable BDV at room temperature (according to ASTM D877 and/or D1816 standard methods) for electric equipment, BDV is likely to be altered when temperature changes occur. The information of BDV at room (20-3... Read More

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<div class="section abstract"><div class="htmlview paragraph">In electric vehicles (EVs), drivetrain lubricants are often utilized not only as a lubricating oil for the drivetrains but also for motor cooling. As such, they are required to both improve the efficiency of the drivetrains and to have a high cooling performance. Both requirements can be met by lowering the viscosity of the fluid, which effectively improves the heat transfer coefficient, reduces churning loss, and improves efficiency. However, low viscosity may adversely affect the fatigue life of gears and bearings. To address these issues, we used a high-performance base oil and optimized additives (e.g., anti-wear agents) to develop a fluid with higher lubricity than conventional automatic transmission fluid (ATF), even though its viscosity is lower. The 100,000-kilometer (WLTC mode) endurance test on an actual vehicle confirmed that there was no damage in the reduction gear unit parts. We also evaluated the torque loss on the reduction gear unit and fuel consumption and confirmed a higher performance in eac... Read More

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Grease composition for lubricating applications like gears that provides stable grease supply and retention. The grease has a base oil of polyalphaolefin (PAO) and a soap thickener. It has a viscosity transition stress of 300 Pa or more at 25°C to penetrate contact areas, but less than 40 Pa at 100°C to prevent grease migration. Shear viscosities at 25°C and 100°C are also optimized to balance grease supply and retention.

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A lubricating oil composition for cooling electric vehicle devices, comprising a base oil containing 30-100% by mass of an ester-based synthetic oil, wherein the base oil has a 40°C kinematic viscosity of 2.00-4.00 mm2/s, a specific heat at 20°C of 1.75 kJ/(kg·K) or less, and a density at 20°C of 0.850 g/cm3 or more.

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Electrically as well as thermally conductive lubricants have drawn considerable attention and are an emerging research topic because they have unique advantages and advanced lubrication performance over traditional lubricants such as corrosion protection and efficient heat dissipation. For instance, some components of electric vehicles (EVs) such as bearings, seals, pads and gears require conductive lubricants to avoid premature failure and electromagnetic interference (EMI) problems due to induced shaft voltages and currents. This review provides a comprehensive overview of the recent developments in conductive lubricants. The review focuses on the important aspects to enhance the thermal and electrical conductivities as well as the tribological behavior (COF, and wear rate) of conductive solid, semisolid, and liquid lubricants. The lubricants that are electrically and thermally conductive with superior tribological performances have been identified through extensive literature review and presented in tabular form. This review summarizes the effect of various additives used to impro... Read More

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A low-traction, high-pressure viscosity fluid formulation for electric vehicle drive units and drivelines, comprising a base oil selected from API groups II-V and an additive, optimized for motor cooling, oxidation stability, and evaporation resistance while maintaining gearbox protection and efficiency.

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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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A lithium complex hybrid grease that combines the high-temperature stability of lithium complex greases with the non-dripping properties of PFPE greases. The grease is formulated by blending a lithium complex grease with a PFPE grease in a specific ratio, resulting in a hybrid grease that exhibits improved high-temperature performance, reduced oil separation, and enhanced water resistance compared to conventional lithium complex greases. The hybrid grease is particularly suitable for applications in the vehicle sector, where it can be used in components such as anti-friction bearings, plain bearings, and timing chains.

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An ionic liquid composition that inhibits chemical degradation of hydrocarbonaceous liquids due to nitrogen dioxide contamination at elevated temperatures. The ionic liquid, comprising a trihexyltetradecyl phosphonium cation and a hydroxybenzoate or salicylate anion, effectively removes nitrogen dioxide from reactive circulation and captures nitric acid, thereby preventing nitration reactions and acid-mediated oxidation. The ionic liquid can be used as an additive in hydrocarbonaceous liquids, such as lubricants, to improve their service life and reduce friction and wear.

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A lubricating oil composition for electric drive units that combines gear oil and motor oil functions, featuring high extreme pressure resistance, durability, and wear resistance, along with high volume resistivity. The composition contains a phosphite ester derivative with a sulfur-substituted alkyl group and a thiadiazole derivative, which are blended with a base oil. This unique combination enables the lubricating oil to meet the demanding requirements of electric drive units, including miniaturized gearboxes and high-force tooth surfaces.

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Hybrid electric and electric vehicles have represented a small portion of the automotive market for many years and mainly use current lubricants, typically automatic transmission fluids (ATFs). However, regulatory compliance to limit greenhouse gases and increased consumer demand have resulted in a rapid global transition to electrified vehicles. This has prompted the need for new advances in vehicle technology to improve efficiency and thereby increase range. Enabling and optimizing such advances requires a new generation of driveline lubricants. Incorporating an electric motor in a transmission or axle, where the motor is exposed to the gear box lubricant, creates new challenges that focus attention on lubricant characteristics that were previously not differentiating features, for example, electrical and thermal properties. Additionally, lubricants must now also be compatible with the constituents used in electric motors which include new polymeric materials and, in some cases, exposed copper. Compatibility tests of these polymers vary within the industry and the risk of copper co... Read More

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Abstract The use of lubricants is commonplace when drilling with water-based drilling fluids. They are less frequently applied when drilling with non-aqueous fluids, as the oil-based drilling fluid is thought to impart a high lubricity. With increased reach of the wells, lubricants are also applied in non-aqueous fluids (NAF) to reduce torque and drag at high angle, for extended reach and horizontal wells to improve drilling efficiency. However, the performance of these lubricants in NAF at extended periods of elevated temperature at downhole conditions is often inconsistent, thought to be hampered by ineffective metal binding and hydrolytic instability of the lubricant molecule. This requires frequent re-dosing and therefore higher cost to maintain performance. In order to identify a better-performing lubricant, it was necessary to better understand the fundamentals of lubrication in a drilling fluid. For example, what portion of the well contributes most to torque and drag? What is the frictional regime that dominates the lubricity between a drill pipe and its contact points? Looki... Read More

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The increasing worldwide demand for hybrid and electric vehicle technology has brought new challenges for the global lubricant industry. The new lubricants for electric vehicles, also called E-fluids or EV-fluids, are expected to meet a new set of requirements including withstanding the much severe operating conditions of EV powertrains. High starting torques, high RPMs and uncontrollable shaft currents passing through the contact interfaces are some of the most challenging powertrain conditions that can impact the performance of these lubricants. Although there have been some papers already reporting on significant alteration of tribological properties of lubricants under electrification, so far there are no standard test protocols aimed at the fast and reliable screening of base oils, additives and formulated lubricants under such conditions. Thus, this research work focuses on exploring the popular four-ball ASTM-D4172 standard method to evaluate the tribological behavior of lubricants under electrified conditions. Specifically, a conventional four-ball tester was instrumented wit... Read More

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A lubricant composition for electric vehicle gearboxes that reduces energy losses by minimizing traction coefficient. The composition includes a base stock and a traction coefficient additive, which can be a polyhydroxyalkyl or polyhydroxyalkenyl carboxylic acid or a polyether compound. The additive is specifically designed to reduce friction between gear components, enabling improved energy efficiency and longer battery life in electric vehicles.

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Lubricant composition for electric vehicle propulsion systems that combines sterically hindered amine or phenol compounds with amine-based and/or sulfur-based antiwear additives to prevent corrosion and wear while maintaining electrical insulation properties. The composition comprises a base oil, one or more sterically hindered amine or phenol compounds as anticorrosion additives, and one or more amine-based and/or sulfur-based antiwear additives, such as dimercaptothiazole derivatives.

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Lubrication is crucial for a sustainable operation of any machinery. A sustainable application of lubricants requires the avoidance of any waste, lubricants should not be exchanged long before their service life has ended. This refers especially to those applications where high operation temperatures are reducing the service life and require a huge consumption of lubricants. Therefore, to fulfil the requirement of sustainability a prediction of the service life at elevated temperatures is crucial. At elevated temperatures the service life of lubricants is limited by thermal aging. This results from a chemical reaction of components of the grease with the oxygen of the ambient air. Such a process follows the Arrhenius equation of chemical kinetics and is given by a straight line in a so-called Arrhenius plot. The slope of the line in the Arrhenius plot is given by the activation energy EA. The FAG FE9 test run is a typical method to assess the service life of a lubricating grease in bearings at elevated temperatures. The test is performed at the upper temperature limit of the grease a... Read More

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A lubricating and cooling fluid for electric motor systems that provides wear protection, friction reduction, and cooling while maintaining low electrical conductivity and copper corrosion resistance. The fluid comprises a lubricating base oil, a sulfurized component, a dispersant system with two dispersants of different molecular weights, and a friction modifier system with multiple components. The dispersants are balanced to maintain low conductivity while providing wear protection, and the friction modifiers are selected to optimize friction reduction while minimizing electrical conductivity. The fluid is designed for use in electric motor systems operating at elevated temperatures, where conventional lubricants may fail to provide adequate performance.

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A lubricant for electric vehicles comprising a base oil selected from carboxylic acid esters, such as 2-ethylhexyl oleate, that provides controlled electrical conductivity, heat conductivity, wear protection, oxidation stability, deposit control, and corrosion inhibition over the lifetime of the lubricant. The carboxylic acid ester base oil enables the lubricant to maintain its lubricating properties despite exposure to high surface temperatures of electrical components in electric and hybrid vehicles.

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Lubricant composition for cooling electric vehicle engines and batteries. The composition contains polyalkylene glycols (PAGs) obtained by polymerizing alkylene oxides like ethylene oxide or copolymerizing ethylene oxide and propylene oxide. The PAGs cool the engine components and batteries by transferring heat more effectively than air or water. The composition can also lubricate engine parts like bearings and gears. It provides an alternative cooling method to air or water cooling for electric vehicles and hybrid vehicles.

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Abstract The market of electric and hybrid vehicles (EVs and HEVs) is expanding exponentially in recent years. It serves as a greener solution in the transportation sector as compared to internal combustion engine vehicles (ICEVs). Conventional lubricants used for ICEVs are not suitable for the EVs and HEVs as the latter operates on electric motors instead of combustion engines. Performance characteristics such as the electrical conductivity, thermal conductivity and copper compatibility are not considered by the ICEVs lubricant but are important for the EVs and HEVs. In this research, computer-aided molecular design technique is used to design the lubricant that is compatible with the EVs and HEVs. The lubricant properties considered are thermal conductivity, specific heat capacity, viscosity, density, and flash point. Group contribution (GC) property prediction model is utilized to ensure that the desired properties are possessed by the generated lubricant. There are six possible solutions of lubricant being generated and discussed. Other properties such as the electrical conducti... Read More

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The most suggestive outlining between the vehicles powered by the electric motor (EVs) and hybrid electric vehicles (HEV) consists in the battery power supplied to the electric motor and unilaterally fulfilling the traction characteristic, while HEVs can only minimize dependence on fossil fuels. The main difference between electric motors and combustion engines in terms of emissions, carbon footprint, and sustainability is that electric motors eliminate the possibility of contamination of oil by soot. In addition, global insights about current Hybrid and EV lubrication involves new specialized lubricants to overcome challenges of electrical compatibility and the short persistence in the environment - known as biodegradability. Biogenic or recycled lubricants have fallen under the incidence of a very high cost for the automotive industry, in contrast to achieving tough performance and efficiency. Nowadays, eco-sustainability proposes future improvement trends. Lubricants from vegetable and animal sources are relevant, coupled with the numerous possibilities of formulating lubricants f... Read More

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Motor oils provide lubricating, thermal control, detergent, sealing, and anti-corrosion properties.These are all provided by motor oil.Many factors act on the lubricating oil while the engine is running, including high temperatures, fuel entering.The study of the processes of oil aging and mechanical impurity dispersion is critical for extending the engine's service life.lubrication temperature, the lubrication system, oxygen contained in the air, and foreign impurities.The oil's properties change as a result of the numerous physical and chemical processes that it goes through: the oil "ages" [1].It darkens during operation, changes in viscosity, flash point, acidity change, molecular

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Lubricants for electric and hybrid vehicles that provide improved efficiency and durability in drive systems, including transmissions and axles. The lubricants comprise a base oil, a gear oil additive, and a molybdenum dialkyldithiocarbamate additive, which provides enhanced protection against electrical corrosion and wear. The lubricants also enable diagnostic and design tools for electric vehicle transmissions and engines by indicating application conditions through color changes.

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Castor oil is an environment-friendly lubricant with good biodegradability and renewable behavior. However, castor oil as a green lubricant has a few shortcomings, such as a low viscosity index and low oxidative stability due to the presence of unsaturated bonds. The temperature affects the lubrication performance of castor oil. In the present study, the lubrication performance and viscosity behavior of castor oil lubricating the friction pair of a steel ball and a nickeltitanium (NiTi) alloy disk were systematically investigated under different temperatures. The results show that the lubrication performance of castor oil is influenced by temperature due to the fact that the viscosity of castor oil varies with the temperature. The coefficient of friction (CoF) of castor oil is as super-low as 0.076 at a temperature of 40C, but is relatively high at other temperatures. The factors affecting the lubrication performance were investigated, and a possible antifriction mechanism is proposed in this study.

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