Water-based Lubricant (WBL) for Electric Vehicle

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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Aqueous lubricant composition for hot forging comprising water, graphite, a thickener, and an alkylated diphenyl oxide sulfonate dispersant. The composition maintains 90% or greater graphite dispersion after 30 days, passing a sedimentation test. The dispersant is a molecule with a specific structure, comprising a diphenyl oxide sulfonate group and an alkylated chain.

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It is well known that lubricating oils reduce the friction coefficient between two surfaces in contact. Since petroleum lubricants are toxic and have a low biodegradability, they are typically not appropriate for the environment. As a result, as public worries about a pollution-free environment grow, so does the demand for lubricants that are acceptable to the environment. The primary rationale for utilizing vegetable oils in forthcoming bio-lubricant formulations is their high lubricating performance, low toxicity, sustainable, and biodegradability. Plant oils hold great potential as a foundational fluid for bio-lubricants, since their synthetic and vegetable oil-based esters provide the most environmentally friendly option for creating lubricants. In this study, Jatropha and Jojoba raw oil were chemically modified via epoxidation followed by transesterification to produce bio-lubricants. Thus, the aim of this work is to develop a bio-lubricant from jatropha and jojoba methyl ester, further adding nanoparticles multiwalled nanotubes and titanium dioxide for improvement of tribologic... Read More

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Electric vehicle transmission fluid formulation designed to meet the unique demands of EV drive systems, providing improved lubrication, wear protection, and compatibility with yellow metals and electrical components. The formulation includes oxidation inhibitors, anti-wear additives, and copper corrosion protection, while maintaining low electrical conductivity and thermal stability. The fluid is engineered to withstand extreme power and torque fluctuations, and is designed to be compatible with a wide range of EV transmission materials.

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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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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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Electric potential controlled lubrication, also known as triboelectrochemistry or electrotunable tribology, is an emerging field to regulate the friction, wear, and lubrication performance under charge distribution on the solidliquid interfaces through an applied electric potential, allowing to achieve superlubrication. Electric potential controlled lubrication is of great significance for smart tunable lubrication, micro-electro-mechanical systems (MEMS), and key components in high-end mechanical equipment such as gears and bearings, etc. However, there needs to be a more theoretical understanding of the electric potential controlled lubrication between micro- and macro-scale conditions. For example, the synergistic contribution of the adsorption/desorption process and the electrochemical reaction process has not been well understood, and there exists a significant gap between the theoretical research and applications of electric potential controlled lubrication. Here, we provide an overview of this emerging field, from introducing its theoretical background to the advantages and c... Read More

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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 composition for electric and hybrid vehicles, comprising a bio-based oil derived from decarboxylated rosin acid, a base oil, and optional additives. The bio-based oil exhibits improved wear prevention, thermal conductivity, and electrical conductivity properties, while maintaining compatibility with conventional lubricant additives. The composition can be used in various applications, including engine oils, gear oils, hydraulic fluids, and transmission fluids, and demonstrates enhanced performance in electric and hybrid vehicles.

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Electric Motors (EMs) containing lubricated bearings must adhere to a variety of operational specifications and related microenvironments.Lubricate products need to perform under these circumstances.The wear and friction of silicon nitride (Si_3 N_4) sliding over toughened chrome steel (52100) were used to measure the tribological effectiveness of three commercially available EM lubricates.The EM lubricates that were examined and comparable viscosity ratings; however, they differed in the proportions of lithium or poly-urea thickener to mineral or synthetic base oil (BO).A variety of surface roughness (SR) levels and temperatures were measured to observe behaviour under various lubrication regimes.The results made possible to compare commercially available solutions directly across a range of application-relevant standards and the analysis techniques created as a foundation for upcoming research on the efficiency of EM lubricate.

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Aqueous lubricant composition for mechanical systems comprising water, glycerol, and hypericin, a natural pigment with biological activities. The composition exhibits excellent tribological properties, including wear resistance and friction reduction, making it suitable for lubricating moving parts in mechanical systems, particularly in vehicle propulsion systems.

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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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Electric and magnetic fields have been used in various ways to enhance the performance of lubrication systems. The presence of these fields can significantly change the properties of lubricants. The rapid adoption of electric vehicles (EVs) has presented new lubrication-related challenges due to the presence of electric current. There is an urgent need for an in-depth study of lubrication systems subjected to such fields. This paper highlights recent research works on several key areas of lubrication involving electric or magnetic fields, which are:1) electric double layer in lubrication, 2) electrorheological fluids, 3) magnetorheological fluids, 4) ferrofluids, and 5) typical fluids used in the current EVs and typical surface failures of bearing components in EVs. Commonly used lubricants in each area are reviewed; lubrication mechanisms and related mathematical models are summarized; methods for and results from numerical analyses and experimental explorations are discussed; and common features of lubrications in different fields are explored. Based on the current research progres... Read More

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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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Friction and lubrication are ubiquitous in all kinds of movements and play a vital role in the smooth operation of production machinery. Water is indispensable both in the lubrication systems of natural organisms and in hydration lubrication systems. There exists a high degree of similarity between these systems, which has driven the development of hydration lubrication from biomimetic to artificial manufacturing. In particular, significant advancements have been made in the understanding of the mechanisms of hydration lubrication over the past 30 years. This enhanced understanding has further stimulated the exploration of biomimetic inspiration from natural hydration lubrication systems, to develop novel artificial hydration lubrication systems that are cost-effective, easily transportable, and possess excellent capability. This review summarizes the recent experimental and theoretical advances in the understanding of hydration-lubrication processes. The entire paper is divided into three parts. Firstly, surface interactions relevant to hydration lubrication are discussed, encompass... 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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Extending the driving range of battery-based electric vehicles is one of the many challenges that need to be overcome before mass adaptation by the public. One of the ways to improve the driving range is to make the power unit more efficient. Currently, ultralow viscosity lubricant is used in power units. The fluid was developed for automatic transmissions and, therefore, not optimized for power unit applications. Before developing an optimized fluid, it is critical to understand the lubrication regimes in power units and quantify the amount of boundary, mixed, and hydrodynamic regimes. Once the relative proportions of boundary, mixed, and hydrodynamic regimes are known, lubricant formulators can select appropriate additive components for the reduction of power losses in those regimes while maintaining component durability (mechanical wear, corrosion, material compatibility, etc.) and lubricant life (oxidation). Understanding the lubrication regimes required an evaluation of power unit efficiency using a production unit under a broad range of speeds and torques. The efficiency data w... Read More

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The hydrodynamic herringbone groove journal bearing (HGJB) shows an excellent performance of high speed, but it suffers from a low load-carrying capacity due to the lubrication behavior of water. In order to overcome this shortcoming, a hybrid water-lubricated HGJB is proposed. A lubrication model for the hybrid water-lubricated HGJB is established. A comparative study is carried out between the hybrid HGJB, the hydrodynamic HGJB and the hybrid plain journal bearing (PJB). The result indicates that the proposed hybrid water-lubricated HGJB has a large load-carrying capacity when running at the start-up or in low speed period, and has a much large load-carrying capacity, a large flow rate and a low temperature rise due to the enhanced pumping effect of herringbone grooves.

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Abstract The reduction of frictional power losses in power transmitting gears takes a crucial role in the design of energy- and resource-efficient drivetrains. Water-containing lubricants like glycerol and polyalkylene glycols have shown great potential in achieving friction within the superlubricity regime with coefficients of friction lower than 0.01 under elastohydrodynamic lubrication. Additionally, a bio-based production of the base stocks can lead to the development of green lubricants. However, one challenge associated with the application of water-containing lubricants to gearboxes is the evaporation of water and its impact on the lubricant properties. In this study, the influence of water evaporation on elastohydrodynamic friction and film thickness was investigated for three water-containing polyalkylene glycols. Two nominal water contents of 20 wt% and 40 wt% and two viscosities were considered. The results show that the friction increases continuously with higher evaporated water content, while the overall friction level remains low in nearly water-free states. A similar ... Read More

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As a sustainable machining lubrication technique, composite electrostatic spray lubrication (CESL) adopts a high-voltage electric field to atomize oils (external fluid) and water (internal fluid) into oils-on-water (OoW). Although castor oil shows excellent lubrication properties, its high viscosity and low electrical conductivity lower the atomization performance and impede the attainment of ideal tribological performance in CESL applications. Blending castor oil with other plant oils is anticipated to effectively resolve this matter through the improvement in chargeability and fluidity. Nevertheless, no research work on the use of blended plant oils to enhance the CESL performance has been conducted. This study employed sliding friction tests between carbide slices and steel discs to explore the tribological performance of CESL under various blended types, blended ratios, external/internal flow rates, and voltages. The physical properties and fatty acid compositions of blended plant oils, as well as the charging and electrowetting capabilities of OoW, were examined to study their i... Read More

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A mobile power tool with a drive unit that achieves energy-efficient operation through the use of an aqueous lubricant during the running-in phase. The lubricant, which can contain nanoparticles, is applied to the drive unit's contact surfaces when the bond roughness is greater than 0.01 μm, allowing for high-quality smoothing of the surfaces and reducing friction and wear.

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Aqueous lubricating composition for electric and hybrid vehicles, comprising water, a polyalkylene glycol, and an antifreeze compound, with optional additives such as corrosion inhibitors, anti-wear agents, and metal passivators. The composition provides both lubrication and cooling properties for the vehicle's propulsion system, including the motor, transmission, and battery, while reducing wear and corrosion.

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An aqueous lubricating composition comprising a gallic acid ester, water, a polyalkylene glycol, an antifreeze compound, and a pH regulating additive. The gallic acid ester, such as lauryl gallate or octyl gallate, provides improved tribological properties, including reduced friction and wear, in the aqueous lubricant. The composition maintains a pH between 8 and 15, and can be used as a hydraulic fluid, lubricant, or coolant in mechanical systems.

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High-efficiency lubricating grease for electric vehicles that reduces energy consumption by optimizing oil viscosity and frictional properties. The grease formulation includes a thickener, lubricating oil, surface-active ester, and additives such as friction reducers and anti-wear agents. The composition can be tailored to achieve specific NLGI consistency grades and viscosity classifications for various EV components.

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To reduce the lubrication failure of water-lubricated bearings under short-term harsh conditions, preliminary experiments have shown that temporarily supplying a small amount of lubricating oil into a bearing as a secondary lubricant can improve the load capacity of the water film therein. However, the physical flow and diffusion state of this secondary lubricant (oil) in water are unclear. Therefore, a mixed lubrication model and a volume-of-fluid model are incorporated to study the diffusion behavior of a small amount of lubricating oil in a water-lubricated bearing. The results show that there is a backflow effect in the local area inside the bearing, where the fluid velocity is in the opposite direction to the linear velocity of the shaft. This backflow effect intensifies with increasing eccentricity ratio, which enlarges the oil-free zone in the middle part of the bearing. In the convergence area at the water inlet end of the bearing, the water supply pressure and backflow effect prevent the lubricating oil from escaping. Increasing the shaft speed has a positive effect on the d... Read More

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Abstract Today, mineral or synthetic oils that are made out of fossil raw materials, are the most common lubricants in gear drive applications. Most of them are non-biodegradable and may pose a risk to the environment. An important step to minimize the risk and the ecological footprint is the use of biodegradable and eco-friendly lubricants. Former research shows the potential of water-based lubricants in gear applications. Therefore, an oil-free, water-based lubricant, was developed for this study. The base lubricant contains plant-based thickeners to generate an appropriate viscosity for a sufficient lubricant film thickness in the tooth contact. In experimental investigations, the sliding wear and scuffing performance has been examined under variation of the added polymers and additives. The scuffing tests A/8.3/RT are performed acc. to DIN ISO 14635-1. The wear tests procedure is based on DGMK 377-01. In both scuffing tests with the sample the failure load stage = 8 was achieved. For case-carburized gears a medium to high amount of wear can be detected. Additional tests with ... Read More

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Aqueous lubricant composition for lubricating mechanical systems, particularly mobile and stationary drive systems, comprising water, polyalkylene glycol, antifreeze compound, and phosphorus compound. The composition exhibits improved tribological properties, including reduced friction and wear, and can be used in applications such as engine and transmission lubrication.

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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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The elimination of mineral oil-based lubricants from machines has multiple beneficial effects on the naturalenvironment. Firstly these lubricants are a direct threat to the environment in the event of leaks; secondly their elimination reduces the demand for crude oil from which they are obtained. In addition, in many cases,e.g. when replacing traditional lubricants with water, friction losses in the bearings can also be reduced due tothe lower viscosity of the water, which reduces the energy dissipation in machines.On the other hand, the introduction of self-lubricating materials or water-lubricated bearings causes problemsrelated to the need to adapt the design of machines and materials used to new operating conditions and changedproperties of the lubricants. In the paper, selected examples of problems related to the use of ecologicallubricants are discussed. The high cost of PEEK based polymers resulted in the emergence of cheapersubstitutes on the market; however, in the conducted research, the substitutes presented worse properties thanthose declared by their manufacturers.

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Eco-friendly lubricants have drawn a lot of interest in the lubrication industry as a way of promoting global sustainability in response to the growing environmental pollution danger posed by the use of petroleum-based lubricants. As a result of these, developing lubricants with organic additives stands as a promising technique in solving the environmental challenges caused by non-degradable materials. This research investigates the effect of bio-based water hyacinth (Eichhornia crassipes) (EC) carboxylmethyl cellulose (CMC) polymer in different base lubricants as well as under different volumetric blend to determine their compatibility effect on lowering friction and wear using base rapeseed oil (BRO) and mineral oil (MO) as a base lubricant sample. High frequency reciprocating rig tribo-tester machine was used in the experiment, followed by substrate surface analysis via energy dispersive x-ray spectroscopy. The additives were evaluated for their potential to improve tribology in terms of friction, surface roughness and wear reduction, load-carrying capacity, and mechanism of repai... Read More

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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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Industries, especially those related to transportation, have relied extensively on petroleum products for lubrication, raising serious questions about the security of the world energy supply in the future. Observed that the end-products might be released back into the environment, posing major environmental risks. As a result, bio-based products have attracted increasing interest as prospective replacement to mineral-based type due to their important role in resolving the issues of pollution. With renewability and biodegradability as their greatest points, bio-based lubricants have been discovered to offer superior lubricating qualities to those of traditional mineral lubricants but currently have some undesirable qualities that need to be improved based on the literatures. Therefore, this research objective is to showcase the potential of bio-lubricants, both in terms of their environmental benefits and for technical applications, based on studies that have been published over the years. Review of the natural oil's molecular structures, physio-chemical characteristics, and lubricati... Read More

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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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The main purpose of the research was to determine the possibilities and experimentally test the benefits ofreplacing conventional oil lubrication with ecological water lubrication. Tests were carried out on a test rigfor hydrodynamic radial bearings under conditions representative of the expected applications for the bearingin water turbines. Bearings made from the polymer material PEEK (polyether ether ketone) were tested understatic loads. The tests were carried out for two types of lubrication: pure water and oil, with a viscosity ofISO VG 46. A comparison of friction coefficients and load-carrying capacity for both lubricants was made.During the tests, an interesting phenomenon of polymer material running in was observed for relatively highpressures when lubricated with a very low-viscosity lubricating medium, i.e., water (pressures in the bearingover 2 MPa).

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Lubricants with a functional water portion have demonstrated a drastic reduction in friction under elastohydrodynamic lubrication conditions. With water-containing polyalkylene glycols, superlubricity with coefficients of friction <0.01 have been measured in model and gear contacts. In addition to the low friction, their calorimetric properties make them particularly interesting for application in electrified vehicles because the liquid can simultaneously serve as lubricant for the gearbox and coolant for the electric motors and the power electronics. In this study, the influence of water content between 8 wt% and 40 wt% of water-soluble polyalkylene glycols on friction and film thickness in elastohydrodynamically lubricated rolling-sliding contacts such as in gears and bearings is investigated. A polyalphaolefine oil is used as a reference. Friction has been measured on a ball-on-disk tribometer and film thickness on an optical tribometer. For a water content of 40 wt%, superlubricity with coefficients of friction down to 0.004 are found. The decrease in friction is up to 95%... Read More

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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 This study explores the rheological and tribological behavior of water-based lubricants (WBLs) as potential alternatives for electric vehicle (EV) applications. As the transportation sector increasingly shifts towards EVs to reduce carbon emissions, the demand for efficient lubricants becomes critical. WBLs here are defined as fluids containing a minimum of 50 wt% water mixed with glycerol, ethylene glycol (MEG), polyethylene glycol (PEG), or one of two polyalkylene glycols (PAGs). Rheological properties were investigated and compared with traditional lubricating oils. Results demonstrate distinctive rheological characteristics in WBLs, with viscositytemperature responses resembling traditional oils with lowered pressureviscosity coefficients. Nevertheless, WBLs exhibit promising film-forming capabilities in highly loaded contacts. Additionally, in sliding contacts, WBLs generally display lower friction coefficients compared to traditional oils, with PEG exhibiting the lowest value near 0.1. These findings suggest that WBLs may offer advantages in reducing friction and ene... Read More

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Abstract The rheological and tribological properties of environmentally compatible lubricants of different bases (native oil, synthetic ester, polyalkylene glycolcontaining oil) compared to a conventional, mineral oilbased lubricant are investigated in order to develop toxicologically harmless and technically suitable lubricants for electromechanical drives. The aging of the oil is also considered. The results of this study reveal that the properties of polyalkylene glycolcontaining and synthetic esterbased lubricants have the potential to act as substitutes for lubricants containing mineral oil. By examining and improving the properties of sustainable lubricants, gear oils that are partially or totally nonmineral oil based will be highly attractive in the future.

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Lubricants play a very important role in multiple industries in minimizing wear and friction between two moving parts. Most lubricants are produced from petroleum oil which is poorly biodegradable and toxic in nature. Hence these lubricants are highly undesirable due to environmental hazards and the health and safety of the operator. Bio-Lubricants like Castor Oil have found a potential scope in research and are being used in various applications as a substitute for these chemical lubricants. This paper examines the Tribological Properties of developed Bio-Lubricants, prepared using Castor Oil and Neem Oil in a mixing ratio of 20%. Wear and Friction analysis has been carried out using Pin on Disc apparatus at varying loads, which has shown that the blend of Castor Oil as a base with 20% Neem Oil has promising properties, with around 70% reduction in wear rate at specific loads, hence showcasing a tremendous capacity for being used in maintenance applications. An overall reduction in wear and coefficient of friction was observed in the developed mixture, making it a potential environm... Read More

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A key driver in current research on lubricant formulation is the need to move away from older technology that is highly reliant on resources derived from industries associated with high carbon dioxide emissions.

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Minimizing energy losses and ensuring smooth motion between engine components is the critical role of lubricants. Extensive research over the past decade has explored various lubricant types and additives. Ionic liquids (ILs) have emerged as promising candidates due to their exceptional tribological performance, which is attributed to their unique physiochemical properties. This review delves into the potential of ILs as both lubricants and additives, focusing on their structure-activity relationship in the quest for identifying green lubricants. Compared to neat base oils, ILs significantly reduce friction and wear. This review explores the role of ILs in water-based lubricants (WBLs) and analyzes the impact of tribo-testing conditions based on different tribometers. A recent trend involves the use of ILs and nanoparticles (NPs) as hybrid lubricant additives. The review examines the synergistic behaviour of these hybrid additives in different base oils and proposes a lubrication mechanism for phosphonium ILs based on tribo-film formation induced by tribo-chemical reactions during th... Read More

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elopment of electric vehicles (EVs) in solving the ICEs pollution challenges. To achieve the expected performance of EVs, the use of suitable bio-lubricants is necessary. In this work, novel lubricants were formulated from jatropha oil as base lubricant using Polytetrafluoroethylene and hexagonal boron nitrate (h-BN) as additives to address the issues of friction and wear during lubrication. The investigation employed a sensitive NANOVEA T50 tribometer machine. The additives' effectiveness in enhancing tribological performance was assessed in terms of their capacity to reduce friction, wear, and load carrying ability. The substrate morphology and elemental distribution on lubricated worn surfaces was done using a scanning electron microscope (SEM) and energy dispersive x-ray (EDX). Under higher loads (25 N), blended 0.5 wt.% poly. + 0.6 wt.% h-BN reduced friction and wear, but at lower (5 N) working conditions, it performed poorly due to lack of frictional energy for the film formation. However, as compared to base jatropha oil, the 0.5 wt% poly. + 0.6 wt% h-BN provided the best fric... 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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Evolving concerns about the environmental harm caused by lubricants derived from mineral oil have given rise to a global trend of using vegetable oil as a base lubricant. Continuous effort to utilize different vegetable oil to replace mineral oil are being carried out by many researchers extensively. Thus, this work evaluates the tribological performance of novel ficus carica (fig oil) combined with Ethylene Vinyl Acetate (EVA) viscosity modifier and Tertiary-Butyl-Hydroquinone (TBHQ) nanoparticles as an eco-friendly lubricant. The evaluation is also done to determine the sustainability property of using fig oil in lubrication. In the study, TBHQ was kept at 0.3 wt.%, while EVA additive was mixed with the fig oil at various concentrations that varied from 0.5, 1, 1.5, and 5 wt.%. An ultrasonic homogenizer was used to combine the samples using the sonication technique. It was found through a viscometric study that 1 wt.% EVA produced the best result. Thermogravimetric analysis (TGA) results showed that EVA + TBHQ inclusion resisted lubricant degradation, while oxidation time shift was... 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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Lubricating compositions for electric and hybrid-electric vehicle transmissions that provide simultaneous lubricating, electrical, and thermal performance. The compositions comprise a solvent system of a base oil blended with a branched diester, combined with low molecular weight poly(meth)acrylate copolymers. The branched diester component is a reaction product of dicarboxylic acids and alcohols with specific chain lengths. The copolymers have a weight average molecular weight of 50,000 g/mol or less and a polydispersity index of 1-2. The compositions achieve electrical conductivity of 80,000 pS/m or less and thermal conductivity of 134 mW/m*K or more.

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