Friction Modifier Lubricant Additives for Combustion Engines

A lubricity modifier for oil products, comprising a compound having the structure of formula (I): R1-R2-C(=O)-N(R3)-C(=O)-R4, wherein R1-R4 are independently selected from alkyl, aryl, and alkylaryl groups, and R3 is a nitrogen-containing group. The compound exhibits good lubricity improving performance in various oil products and has good stability.

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Engine oils undergoes various chemical and physical changes during its lifetime, which can result in reduced lubricant performance and affect fuel economy. The efficiency of engine oils is determined by additives in the lubricant. Molybdenum dithiocarbamate (MoDTC) is a friction modifier that has been used in automotive engines. However, decomposition mechanism of MoDTC in commercial engine lubricant is not fully understood.

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A lubricant composition for internal combustion engines that achieves improved fuel economy without compromising lubricant life or engine cleanliness. The composition combines low-viscosity, low-volatility base oils with ashless succinimide dispersants, and can include additional additives such as antiwear agents, detergents, and friction modifiers. The base oils have a kinematic viscosity of less than 3.7 cSt at 100°C and a NOACK volatility of less than 25 wt%. The composition is suitable for use in 0W-XX multi-grade engine oils.

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Abstract In-cylinder internal combustion engine parasitic frictional losses continue to be an area of interest to improve efficiency and reduce emissions. This study investigates the frictional behavior at the oil control ringcylinder liner conjunction of lubricants with anti-wear additives, varying dispersant concentration, and a range of friction modifiers. Experiments are conducted at a range of temperatures on a cylinder liner with a nickel silicon carbide coating. A novel motored reciprocating tribometer, with a complete three-piece oil control ring and cylinder liner, was used to isolate the friction at the segmentliner interfaces. Four lubricants were tested, three with the same 3% dispersant concentration and 1% zinc dialkyl dithiophosphate (ZDDP) anti-wear additive: the first with no friction modifier, the second with inorganic friction modifier (molybdenum dithiocarbamates), and the third with organic friction modifier (amide). A fourth lubricant with an organic friction modifier with a 9% dispersant concentration was tested to compare the effect of the level of dispersan... Read More

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In today's world, energy efficiency is one of the key factors in the development of technologies. Particular attention is paid to internal combustion engines (ICE), which are actively used in various industries and transport. Since overcoming friction consumes up to a quarter of the energy resources consumed, one of the promising tools for improving the energy efficiency of these engines is the use of friction modifiers in lubricants. The article considers the main types of antifriction additives with a brief description of the mechanisms of their action, the main advantages and disadvantages, tested the most common friction modifiers of different nature in the composition of 10w-40 API CI-4 oil on the friction machine 2070 SMT-1 and quantitatively shows the difference in the effectiveness of the selected additives, made conclusions about the most effective additives and dosages of input, as well as the factors limiting the introduction of lyophilic molybdenum modifiers.

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Friction and wear play crucial roles in automotive engine performances and their efficiency. Overall, 40% of fuel power loss occurs in friction of various components of the engine. Frictional loss between piston rings and cylinder liner assembly contributes major loss of fuel power in the automotive engine and it is about 15% of total fuel power loss occurs due to friction. In the present scenario, thin film coating techniques are in trend to enhance the mechanical and tribological properties of machine components. In this paper, different types of wear-resistant, corrosion-resistant, and antifriction coating materials and their characteristics are discussed. Also, carbon-based coatings, nitride coating, carbide coating, oxide coating, and the intermixing of counterparts of coating material to form a composite coating, multilayer coating, and varying their percentage elemental composition composite are reviewed and compared. The synergistic effect of coating with texturing over the piston ring is discussed. Finally, recent developments and new possibilities of coatings that can be em... Read More

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<div class="section abstract"> <div class="htmlview paragraph">This document covers the mechanisms from the power cylinder, which contribute to the mechanical friction of an internal combustion engine. It will not discuss in detail the influence of other engine components or engine driven accessories on friction.</div> </div>

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Friction and wear between sliding surfaces can lead to various issues in industrial applications, such as increased costs, reduced machine lifespan, loss of functionality, energy loss, and decreased system efficiency. To mitigate these problems, lubricants and coatings are commonly employed. This study aims to investigate the impact of coatings and lubrication on friction coefficient, wear volume loss, and lubricant temperature using the block-on-ring wear test. The effectiveness of different coatings (uncoated, DLC, CrN, and TiALN) and lubricants (anti-friction graphene oxide additive oil and strong nano engine oil additive) in reducing friction and wear is evaluated. The block-on-ring tests are conducted under varying loads (6-60 N), speeds (1450 rpm), lubricant volumes (40 ml), and durations (2-20 min). The coefficient of friction is measured using an inline load cell, wear volume loss is determined by weighing the blocks before and after the experiment, and lubricant temperature is monitored using thermocouples. The results indicate that the coefficient of friction decreases with... Read More

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Experimental studies of the effect of adding the antifriction additive Multi-Tech-Conditioner to lubricating oil on the power of mechanical losses of a rotary piston engine were carried out, the purpose of which was to reduce the cost of potential energy of a compressed working fluid to overcome friction forces. The experimental data obtained make it possible to estimate the value of irretrievable losses of the available power of a rotary piston engine at the stage of its design and operation. Experimentally, a positive effect of the addition of the Multi-Tech-Conditioner antifriction additive to lubricating oil on the change in the power of mechanical losses of the engine was established, which was reflected in a decrease in total losses over the entire operational range of change in the rotor speed by 11.8 %. As a result of the research, it was determined that the losses for pumping strokes (gas exchange) in a rotary piston engine amount to 31.6 % of the total power of mechanical losses. An assessment was made of change in the mechanical efficiency of a rotary piston engine with a ... Read More

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Purpose This paper aims to determine a suitable anti-wear and friction-reducing compounding additive for lithium greases (LG) by investigating the effects of three single additives potassium borate (PB), zinc dialkyl dithiophosphate and molybdenum dialkyl dithiophosphate (MoDDP) and two compound additives on the friction, wear and extreme pressure properties of LG. Design/methodology/approach The effects of the above five additives on the friction, wear and extreme pressure properties of LG were investigated using an SRV-5 friction tester. An X-ray photoelectron spectrometer was used to analyze the various elements presented on the wear surface as well as the types of compounds. Findings The compound additive suitable for grease consists of PB and MoDDP, which have excellent friction reduction, anti-wear and extreme pressure properties. And a boundary protection film consisting of oxide and MoS 2 is formed on the friction surface, thus improving the friction reduction and anti-wear performance of the grease. Originality/value This study can improve the anti-wear and friction-reductio... Read More

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Abstract This paper mainly studies the tribological performance of friction pairs and poor lubrication during piston movement. Based on the average Reynolds equation and comprehensively considering the variable viscosity and variable density characteristics of lubricating oil, a transient hydrodynamic lubrication model of the piston ring-cylinder liner friction pair is established. By solving the established lubrication model, the lubricating oil film thickness value, friction value and other parameters that can characterize the lubrication performance of the friction pair throughout the cycle are obtained, whilst revealing the surface roughness, lubricating oil viscosity and piston ring barrel surface height. And the influence mechanism of the friction performance of the friction pair is presented on the basis of the previous analysis. The research shows that improving the surface roughness of the piston ring will help to improve the lubrication, increasing the viscosity of lubricating oil will help to improve the lubricating performance of friction pairs and reduce the peak frictio... Read More

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To expand the applications of polymer friction modifiers in low viscosity oils suitable for hybrid power systems, the tribological properties of five kinds of oil samples at different temperatures were studied, which were compounded with polymer friction modifiers Perfad XG 2500, molybdenum dialkyl dithiocarbamate (MoDTC), zinc dialkyl dithiophosphate (ZDDP). When Perfad XG 2500 is used alone, it forms a brush-like surface film at low temperatures, which can provide lower initial friction. With the rise in temperature, its antifriction effect decreases significantly, which is related to the desorption behavior of physical film. When Perfad XG 2500 is combined with MoDTC, it has the best synergistic antifriction effect, and the average friction coefficient is reduced by a maximum of 20.83% (90 C). Its friction coefficients decrease significantly with the increase in temperature due to the dissociation process of MoDTC catalyzed by high temperature. However, there are many furrows on the worn surfaces, and the sharp features of the profiles are obvious. When Perfad XG 2500 is combined... Read More

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In the developing fields of automobile, a vital role has been played by Internal Combustion Engines. The performance of Internal combustion engines depends on the combustion process that occur in the engine's core. The heat energy delivered in combustion should be converted into practical work in considerable amounts to achieve better engine efficiency. Some of the losses that occur in the engine reduce the conversion percentage of heat into work. The frictional loss contributes a key role in reduction of IC engine's efficiency. As the IC engine consists of several moving components, the friction generated against the total power delivered is assumed to be high. A proper lubricating system with a suitable lubricant and desired properties reduces friction and increases engine performance. In this work, the experimental evaluation on a four-stroke CI engine with a twin-cylinder was carried out using commercial lubricants SAE 40 & SAE 60 and the blend of those conventional lubricants along with viscosity index improver PMA. The current work concentrates on experimental analysis of desir... Read More

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Abstract Downsizing in spark-ignited engines becomes one of the most effective concepts to achieve fuel economy and emissions requirements and drives operating conditions of major moving engine components into more mixed and boundary lubrication regimes. Piston ring design faces considerable challenge to reduce friction losses, oil consumption, blow-by, and wear. Surface coatings have received great attention in applications of automotive engine components due to their unique friction properties. In this study, an elasticplastic contact model of rough surfaces with hard coatings is used to provide proper design of the ring coating thickness concerning the plasticity-yielding resistance of stiff coating. A diamond-like carbon (DLC) coating with surface hardness higher than current production ring coatings has been evaluated in additive-free base oil and fully formulated engine oil under boundary and mixed lubrication conditions. The friction behavior of the coated material relative to uncoated materials is compared in boundary and mixed lubrication regimes. A traction-merging rolling... Read More

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Microencapsulated friction modifiers for lubricants that survive harsh engine conditions and release additives as needed. The microcapsules are designed with controlled porosity and surface charge to enable diffusion-release of additives and pass through oil filters. They can contain multiple additives, including friction modifiers, antioxidants, and antiwear agents, and are triggered to release by thermal, shear, or temperature set points. The microcapsules are produced using novel processing methods that enable consistent wall thickness, shape, and mechanical strength, overcoming limitations of conventional microencapsulation techniques.

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A method for producing a stable, oil-soluble organometallic salt composition comprising copper, comprising reacting copper carbonate particles with a carboxylic acid at a lower temperature and pressure than conventional methods, resulting in a faster reaction rate and higher conversion of the metal carbonate to the organometallic salt. The resulting composition is useful as a lubricant additive that reduces friction and provides wear protection, and is soluble in a wide variety of hydrocarbon oils.

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As one of the important friction pairs of a diesel engine, the cylinder-liner piston ring (CL-PR) faces a harsh high-temperature working environment. To explore the mapping relationship between the friction performance of the CL-PR and the change in temperature, the reciprocating-friction and wear-testing machine was used to analyze the friction performance and lubrication performance of four kinds of lubricating oil at different temperatures (room temperature, 60 C, 90 C, and 120 C) from the friction coefficient, contact resistance and surface topography. The results show that the tribological properties of the four lubricating oils show different trends with the increase in temperature. The friction coefficient of the base oil first decreases and then increases with the increase in temperature; this shows that the friction property of the base oil is improved by a certain temperature rise, and the increase in temperature promotes the formation of an oxide film and reduces the friction coefficient. While the friction coefficient of other three lubricating oils with specific appli... Read More

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The paper highlights the results of anti-friction and anti-wear tests of samples of lubricating media containing a layered friction modifier - molybdenum diselenide. The main variable test conditions are the load on the test samples, volume concentration of the layered friction modifier in the lubricating oil, preliminary storage time of the lubricating composition before testing. The main evaluation criteria are the mass wear of samples, wear intensity, friction coefficient. Each of the eight test cycles was implemented on a tribotechnical installation of an original design using a cylindrical contact type. The resource indicators transferred from the model conditions of the tests to the real tribological unit ring-cylinder of a marine diesel engine 6ChSP 18/22 were evaluated. According to the results of tribological studies, the effect of increasing the load on the model friction unit of the installation, containing a cylindrical wear pair of alloyed gray cast iron, was revealed, as a result of which the mass wear of the annular movable sample increases, and the resource transfer... Read More

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Anti-wear (AW) additives and friction modifiers (FMs) and their interactions in lubricants are critical to tribological performance.

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As the power core of automobile-internal combustion engine, the friction power consumption of piston-liner system friction pair is as high as about 50% of the friction loss of the whole internal combustion engine. After thousands of years of evolution, species in the biological world have formed excellent body surface structures to resist friction and wear. This paper intends to apply the self-lubricating earthworm surface shape to the piston skirt, which is the main friction pair in internal combustion engine, and study the macroscopic fluid lubrication state of the whole piston skirt with bionic shape. CLX-2V engine was used as experimental carrier. Through the change of oil film thickness caused by thermal-mechanical coupling deformation of piston skirt, combined with the average Reynolds equation, the hydrodynamic pressure of lubricating oil, shear stress and skirt friction force are obtained to verify the contribution of bionic shape to piston drag reduction, wear reduction, wetting increase and friction power consumption. The results of simulation and test show that the lubrica... Read More

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Engine test rig runs with a standard and a friction modifier containing premium fuel using an artificially altered close to end-of-life oil were conducted. Friction modifier and antiwear additives were completely degraded in the oil at the start of the test. Radioisotope activated piston rings were utilized in the engine, which allowed wear determination via radioisotope concentration measurements. Additionally, 3D topography of the piston rings and determination of the iron content in the engine oil were performed to determine wear that occurred during the test. The engine test runs resulted in comparable fuel dilution with standard and premium fuels, namely 0.84 0.98 m% and 0.69 0.80 m% respectively, which indicates comparable physical interactions between the engine oil and the two fuel formulations. All 3 independent methods for wear measurement confirmed that the premium fuel containing friction modifier results in an overall superior wear protection compared to standard fuel. Mass spectrometry of oil aliquots from the engine test rig runs showed an accumulation of friction ... Read More

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Abstract The prediction of tribological characteristics of the piston ring-cylinder liner friction (PRCL) assembly near the top dead center has been a difficult area of research. This study explores the micro-friction behavior of PRCL assemblies near the top dead center in engines using the molecular dynamics approach. The tribological characteristics of the PRCL were analyzed under various operating conditions such as ring sliding speed, ring back load, operating temperature, and lubricant supply amount. The liner surface morphology, liner wear, and lubricant film distribution were used to evaluate the tribological characteristics. It was determined that the lubricant supply amount has the most significant impact on the micro-friction behavior of the PRCL assembly.

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As the main friction pair of engine, the friction loss of piston-cylinder liner assembly in the working process has become the main reason of engine friction power consumption. Many species in the biological world have formed non-smooth forms of resistance reduction after thousands of years of survival and evolution. Many people have applied this non-smooth shape of drag reduction on organisms to the surface of friction pairs in construction machinery. Based on LX108 engine, the wear and erosion resistance of Scapharca subcrenata surface is applied to the piston skirt, which is the main friction pair in the engine. Nine test schemes were designed according to orthogonal test. This design selects three factors, namely, groove distribution type, groove depth and width, groove spacing, and each factor includes three levels. The macroscopic fluid lubrication state of the whole piston skirt with bionic shape is studied. Through the change of oil film thickness caused by thermal-mechanical coupling deformation of skirt, combined with the average Reynolds equation, the hydrodynamic pressure... Read More

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Friction modifier (FM) is widely used in the curve section to suppress the damage and noise between the wheel and rail. This paper compared typical third body materials, including water, oil and FM to explore their influencing mechanism on wheel-rail adhesion and damage. Furthermore, FM samples containing different solid particles were prepared. The tribological performance of these FM samples, water and oil were tested with a twin-disc testing apparatus and a hand-push tribometer. The results indicated that the shear strength of the third body material plays a vital role in the friction. The hardness of solid particles in FM greatly influences the friction control performance of FM. The change in the hardness of the solid particles makes the FM exhibit either "lack of lubrication" or "over lubrication", that both are detrimental to the wheel and rail interface. For FM material, it is necessary to select solid particles according to the adhesion and damage comprehensively. The most suitable particle in this paper was kaolin.

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In modern internal combustion engines, the lubricant viscosity affects greatly the friction power loss. To obtain maximum fuel economy of the engines, the lubricants with different viscosities are considered to evaluate the friction properties of the compression ring-cylinder liner conjunction in the engines in this study. To conduct the evaluation, an improved mixed lubrication model is developed with considerations of the cylinder liner deformation, the lubricant thermal effect & transportation, and the change of lubrication condition from full flooded to starve. On this basis, the influence of different viscosity lubricants on the minimum oil film thickness, friction, power loss, FMEP, and wear load are investigated. The numerical result indicates that the low viscosity lubricant is more beneficial to facilitate the change of lubrication condition from starve to fully flooded. Furthermore, the low viscosity lubricant will result in large wear load on the compression ring surface while reducing the friction power loss.

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Internal combustion engines are increasingly regulated in regard to efficiency and environmental impact, which requires advanced optimization strategies of engine components. The contact between the top ring and the cylinder liner is critical to the efficiency of an internal combustion engine. As shown in a previous study, an amorphous carbon coating can greatly improve the friction properties of piston rings. This work expands on these results by fabricating laserinterferenceinduced microchannels on the coating perpendicular to the direction of movement with a mean depth of 0.97 and 3.13 m spatial period to further optimize the tribology. Fired singlecylinder engine measurements of the microtextured rings show a significant reduction in mean piston assembly friction of 5% for operation points that are relevant for urban transportation and up to 10% for specific operation points. Subsequent multibody elastohydrodynamic simulations prove that measured friction changes result from the compression ring microtexture. In particular, the microtexture increases the hydrodynamic pressure... Read More

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Friction loss in an internal combustion engine largely depends on elastohydrodynamic lubrication. The piston compression ring is a contributor to such parasitic losses in the piston subsystem. The complex elastodynamics of the ring are responsible for the transient and regime-altering film that affects the elastohydrodynamic lubrication of the ring liner contact conjunction. The current paper will discuss the ring radial, lateral deformation, and axial twist, and its effect on the film profile of the compression ring and its subsequent effect on tribological characteristics like elastohydrodynamic pressure, friction, and lubricant. A finite difference technique is used to solve the elastohydrodynamic issue of elastodynamic piston compression by introducing the elastodynamically influenced film thickness into the lubrication model. The results show that consideration of the elastodynamics predicts a 23.53% reduction in friction power loss in the power stroke due to the elastodynamic ring compared to the rigid ring. The elastodynamic effect improves the lubricant oil flow into the conj... Read More

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Lubricant is used to decrease wear on two surfaces that come into contact with each other, and additives can aid to improve the lubricant's performance. Engine oil is the lubricant that we use in combustion engines, and ex-ternal additives that are available on the market can be added to the engine oil to improve its performance. The purpose of this study is to see how ex-ternal additives affect the tribological performance of engine lubricants. The performance of three lubricant samples was investigated in this study: commercial engine oil (SAE10W-30), engine oil mixed with friction modifier additives, and engine oil mixed with anti-wear and extreme pressure additives. The mixtures' viscosity, coefficient of friction (COF), and wear scar diameter (WSD) were determined using viscometer, four-ball tester, and high-performance microscope. The findings show that the mixes behave differently than commercial oil. Even though adding additives to engine oil is sup-posed to boost performance, the flash temperature parameter (FTP) deter-mined from WSD, and the frictional behaviour a... Read More

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In internal combustion engines, the valvetrain is responsible for up to 25% of the friction losses, at rotational frequencies below 2000 rpm. Important friction losses in valvetrain come from the contact between the cam and the tappet. Despite to manufacturer specifications for the engine lubricant, the lubricant viscosity can be changed under some conditions, affecting the cam-tappet contact forces. Also, the surface conditions of cam and tappet can affect these friction forces. This work presents a bench mono-valve experimental apparatus and results for frictional force investigations, using aged engine lubricant SN5W30, with viscosity modifications. The influence of a tappet crown coated with H-DLC is investigated, comparing to standard tappets. These experiments showed that, under specific experimental conditions, the friction forces between the cam and the tappet are the lowest with H-DLC application, for all lubricant viscosity applied.

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Effective lubrication between rubbing surfaces is required to reduce friction and wear. Conventional lube oils traditionally contain a package of additives that significantly improve their tribological properties. Antiwear and load-carrying additives improve boundary lubrication and reduce wear of the rubbing surfaces due to the formation of quasi-liquid crystalline layers on them [1]. Such structured layers with molecular ordering determine the tribological characteristics of the friction units

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As low-viscosity oil is used more widely to reduce friction losses in IC engines, concerns are growing about an increase in friction, wear and scuffing at the sliding surfaces on tribo-components. The authors conducted an analytical study on thermal friction characteristics of boundary lubrication based on the physical and chemical properties of interface materials and lubricants. The study was intended to investigate the effect of temperature on the function of oil additives as a friction modifier and/or anti-scuffing agent. Three low viscosity base oils, three extreme pressure and anti-wear agents and two organo-molybdenum friction modifiers were used to measure friction changes with a cam/follower test apparatus. The authors analyzed a relationship between friction and temperature in the running-in process of interfaces in consideration of the functional sensitivity of additives in low-viscosity oils. This analysis was focused on physicochemical properties on the basis that the oil viscosity, the adsorption of oil molecules, the chemical reaction of oil additives that forms a trib... Read More

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The viscosity of motor oil gets lower in order to decrease resistance at region of the fluid lubrication. On the other hands, this causes increasing of friction at the boundary lubrication region. For this reason, it is required to use a friction modifier to reduce the boundary friction. MoDTC is especially used as friction modifier. Although the decomposition mechanism of MoDTC has been presumed, it is considered only in the case of metal, not hard coatings. So, it is required to understand the effects of hard coatings to friction in motor oils. We tried to clarify the surface and tribofilm changes depending on the kinds of hard coatings by SEM-EDX, TEM and so on. As a result of experiment of hard coatings against metal, we clarified the process as follows when friction of CrN reduces. In the early stage of friction, Fe of the opposite metal transfers to CrN. Mo2S2O2 intermediate product which is formed by MoDTC decomposition is formed on CrN divided into Fe oxide and Mo sulfide. At this time, crystal orientation between Fe oxide and CrN is matching because the lattice constant of F... Read More

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The paper presents the results of laboratory studies of a number of additives introduced during operation to motor oil of internal combustion engines. It also evaluates their impact on tribological characteristics of friction pairs. It was found that all studied additives have a positive effect on the running-in quality. Reduced wear of friction pairs, reduced surface roughness compared to base motor oil is determined. The best indicators were recorded with the FENOM additive. The decrease in wear was 46% and roughness 23.5% compared to the base oil.

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The tribo-performance of passenger car engine oil with three friction modifiers (organic and inorganic) has been experimentally evaluated using benchtop tribometers. Friction coefficient traces and wear and contact potential (qualitative measurement of lubricating film formation) were reported at varying contact pressures, speeds, and temperatures. The in situ film-forming characteristics of friction modifier in engine oil were also investigated and reported using SLIM (Spacer layer imaging) in a Mini traction tribometer. Overall, inorganic friction modifiers (MoDTC) yielded better tribological performances than organic friction modifiers. Typically, thicker protective tribo-film (180 nm) formed at the worn surface by MoDTC than organic friction modifiers (80120 nm). Scanning electron microscopy (SEM), Raman spectroscopy and Atomic force microscopy (AFM) have been utilised to characterise the worn surfaces and understand the mechanism behind the protective tribo-film formation.

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Wear is one of the main factors that degrade the economic, power, and environmental performance of internal combustion engines. As well as reducing the reliability of their operation in general.Therefore, the purpose of this study is to define a method, physical and chemical, to increase the wear resistance of friction-pair parts, as well as to study its effect on economic, power, and environmental indicators. The internal combustion engine VAZ-11194 was used as a test object. To remove economic, capacity, and environmental indicators, we used an electric brake stand with induction brake FROUDE AG-150, installing a gas analysis AVL CEB-11, and a DFL-1 piston fuel flow meter. Test results were recorded after the engine had been running for 5, 50,100 hours. To evaluate the effect of the anti-friction additive, the tests were carried out in two stages (without the anti-friction additive and with the addition to the oil system). As a result of adding an additive, the torque (MT) increased by 30% on average, the power (Ne) increased by 4.1% on average, specific fuel consumption (SFC) decr... Read More

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Abstract To abate frictional loss, advanced coatings are vital for piston rings, thick low friction environment-friendly carbon coatings have been deposited using HVOF spray (High Velocity Oxy-fuel) technique. The COF (Coefficient of Friction) was found in the range of 0.3 to 0.45 whereas the wearing range was about 45150 m during the tested conditions. After wear test at high temperature, the developed coating shows that micro-hardness was increased about 11.5%, 90% reduction in residual stress, COF decreases to about 50%, and wear decreases to about 70% under test conditions. The experimental result of the conducted corrosion test illustrates that the overall measured mass loss per unit area of the as deposited sample was decreased to be about 85.7% at an exposure time of 1 h, 63.6%, at an exposure time of 3 h, and 55% at an exposure time of 5 h.

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The paper presents the results of studying the influence of variable characteristics of lubricating oils for marine diesel engines (concentration of layered friction modifier in lubricating oil, viscosity of lubricating oil, contact pressure in the friction zone) on the tribological parameters of parts of the cylinder-piston group of marine diesel engines. There are considered the aspects of increasing the reliability and wear resistance of the cylinder-piston group of marine diesel engines when a layered friction modifier is added to the base lubricating oil in a concentration of 1.5 vol.%. There have been carried out the comparative tribological studies of M-16G2CS lubricating oil including an additive based on molybdenum diselenide. Dependences of the wear of parts of the cylinder-piston group of a marine engine on different parameters of the studied lubricants are shown. The wear rate of experimental samples in conditions of variable characteristics of lubricants has been studied. According to the tribological studies of lubricants and structural materials, the tribological ratin... Read More

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Currently, there are many methods of reducing the friction losses of the main components of an internal combustion piston engine. The operating conditions of internal combustion piston engines intended for the propulsion of ultralight aircraft differ significantly from those prevailing in the case of using these engines for the propulsion of vehicles. There are many studies on the influence of selected anti-wear coatings on the friction coefficients when using various lubricants, measured via tribometers. Unfortunately, the conditions obtained in the laboratory significantly differ from those prevailing in an engine operating under external conditions. The study investigated the influence of a change in the tribological parameters of TiN, TiAlN, CrN and DLC1 anti-wear coatings on the moment of resistance to the piston movement of an aircraft engine. The operating parameters of a real engine working in an aircraft were simulated. The main focus was on the coating layers of the sliding surfaces of the piston rings and the cylinder running surface. The properties of the coatings affect ... Read More

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Abstract To extend drain intervals and improve efficiency, new engine oils with increased dispersant concentration and reduced viscosity are required. Low viscosity engine oils can increase the prevalence of boundary friction at low temperature and increase its severity at higher temperatures. As a result, combinations of organic and inorganic friction modifiers (FM) will be used to reduce boundary friction across a range of temperatures, also preventing damage to vehicle catalysts. This paper presents an experimental case study of such a new generation of fully formulated engine lubricants with varying concentrations of polyisobutylene succinimide dispersant, organic, and inorganic FM. Representative conditions pertaining to those encountered at the top dead center reversal of the piston compression ring-cylinder liner contact are created, and the generated friction measured through use of a sliding-strip tribometry. Subsequently, X-ray photoelectron spectroscopy (XPS) is used to determine the composition of the formed surface tribofilms in order to explain the observed frictional c... Read More

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Abstract In internal combustion engines, significant power losses are directly related to the mechanical friction of engine parts. Therefore, controlling tribological performance for engine lubricants has a major role in limiting those losses. In this study, the tribological properties of traditional engine oil with nano ZnO and oleic acid (OA) as a surfactant have been analyzed. Three different concentrations of 0.2, 0.5 and 1 wt.% were investigated using a pin-on-disc tribometer, according to ASTM G-99 with boundary/mixed lubrication regimes. The generated friction and wear characteristics revealed a remarkable reduction in friction coefficient with a range of 810%. Analysis of SEM and EDX was conducted on the worn surfaces. Additionally, the colloidal stability of nano dispersion was performed through sedimentation, FTIR, and Zeta analyses.

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Friction loss is one of the main factors affecting engine power. Reducing friction power losses to improve the power of engines is a significant concern for designers. Especially, under the background of energy-saving and emission reduction, it is indispensable to carry out an in-depth investigation on engine bearing lubrication characteristics. Unlike the previous studies of separate modelling, a new modelling method of coupling the dynamic and lubrication model is proposed in this paper. The bearing capacity, friction force, friction coefficient and eccentricity ratio were taken as the evaluation criterion, and the influence of design parameters such as angular speed, bearing radius and width on the lubrication efficiency and friction power loss (LE-FPL) were studied. The results indicate that increasing the angular speed, bearing radius or width can effectively reduce the eccentricity ratio and raise the minimum oil film thickness, which is beneficial to improve the lubrication efficiency. However, the above methods to improve engine lubrication efficiency will lead to more power ... Read More

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A lubricating composition for internal combustion engines that provides improved fuel economy and wear protection. The composition comprises a low-viscosity base oil, a functionalized ethylene-alpha-olefin copolymer, and a poly(meth)acrylate polymer. The functionalized copolymer contains an acyl group grafted with a hydrocarbyl amine, and the poly(meth)acrylate polymer is a block or tapered block copolymer with a first block insoluble in the base oil and a second block soluble in the base oil. The composition maintains good high-temperature viscosity and exhibits excellent performance in the DW10 Lash Adjuster Test, a standard test for engine wear protection.

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A class of liquid organic compounds with improved lubricant performance, comprising N-[3-[(2,3-dihydroxypropyl)(3-alkoxypropyl)amino]propyl]alkylamides and unsaturated or branched N-[2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethyl]-alkylamides. These compounds exhibit enhanced friction reduction, wear protection, and corrosion resistance, particularly against copper and lead, while maintaining a liquid state at room temperature.

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Fuel additive compositions that improve fuel efficiency of internal combustion engines by synergistically combining a zinc chelating agent and a friction modifier with at least one polar group. The zinc chelator limits friction caused by zinc dithiophosphate, while the friction modifier forms a friction-reducing film on zinc phosphate surfaces. The combination provides unexpected levels of friction reduction and fuel economy enhancement.

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The tribotechnical coating helps to reduce the coefficient of friction and improve the fuel efficiency of the combustion engine. There are many different oil additives on the market, and in most cases the manufacturer gives little data on the consequences of their use in the engine, the specific results of such use, and does not disclose information on the mechanisms of action of these compositions. A separate issue is the study of the effect of these additives on the properties of engine oil and the mechanisms of its aging. The paper presents the results of using the tribological composition ArmActiv Moto 4 in a single-cylinder diesel engine. The test program provided for the introduction of the additive according to the manufacturer's instructions and its subsequent change after the processing interval to obtain the results of the effect of the additive on the surface of engine parts. The results of measuring the power, torque and fuel consumption of both the base engine and the engine treated with the tribotechnical composition are presented. The research results showed that as ... Read More

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Abstract Friction modifier additive technologies play a crucial role in controlling friction and wear of lubricated tribological systems. Novel additives are usually evaluated using formulations of varying concentrations. It can be very difficult to understand the underlying mechanisms in those laboratory tests because of the interaction of base oil with the additives. It thus can be insightful to perform model experiments in a controllable atmosphere. This can be achieved for instance by integrating a tribometer into a vacuum system comprising in-situ surface analytical methods.In this work, a nitrogen containing organic friction modifier is adsorbed from the gas phase onto a Fe2O3 surface. Different coating thicknesses are prepared by varying the duration of the vapor deposition, so that the influence of the coating thickness on the friction behavior can be investigated. The chemical composition of the coated surfaces is also analyzed by coupling to an XPS photoelectron spectrometer.Contrary to the assumption that layers are formed, this friction modifier accumulates in droplets on... Read More

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5.1 The efficiency and fuel economy of spark ignition and diesel engines is affected in part by the friction between moving parts. Although no reliable, in situ friction measurements exist for fired internal combustion engines, it has been estimated that

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The elements creating friction pairs are described to be very difficult in terms of determining all the optimal parameters. The present research on the stability of friction pairs is focused on the surface and the top layer of the surface. The main goal is to find new design solutions and materials which would allow the vehicle to cover a lot of kilometres before the main repair of the combustion engine. The biggest structural difficulties are noticeable in friction pairs where a sliding and returning motion can be observed, which is connected with the sealing function. A typical example of such a pair is that of the piston ring-cylinder. Engineers are working on defining an additional factor that would be able to reduce the tangential force by reducing the friction coefficient in the elements of the friction pair. The molecular structure and nature of the bonds between the molecules present in the material suggest that the free surface energy may be such a factor, because it determines the tribological properties of the material, which is reflected in the stability of the units. The... Read More

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Organic friction modifiers (OFMs) are often used with zinc-dialkyl-dithio-phosphate (ZDDP) in engine oil formulations to reduce boundary friction while maintaining the anti-wear property of ZDDP. This study investigated the interaction between fatty acids and ZDDP. The results showed that the adsorption of fatty acids determines the friction coefficient when fatty acids are used alone. The friction coefficient was smaller when a denser fatty acid adsorbed layer was formed. Neutron reflectivity (NR) measurement revealed that, for a fatty acid-ZDDP combination, the fatty acid also contributes to friction behavior; a synergistic effect occurred only with a reduction in the interface metal thickness. These results suggest that the fatty acid-ZDDP combination promotes metallic soap formation, which reduces friction.

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Friction, wear and tribofilm growth of organic friction modifiers (glycerol monooleate and oleamide), anti-wear additive (ZDDP) and binary additive system comprising the organic friction modifiers and ZDDP were studied in polyalphaolefin (PAO) and ester oil. The mechanisms underlying base oil polarity-dependent frictional performance of the OFM and AW additives at high temperature (140 ), either singly or in combination, were investigated in the light of chemical composition analysis of the tribofilms post friction measurements using energy dispersive X-ray spectroscopy (EDX), static and dynamic time-of-flight secondary ion mass spectrometry (ToFSIMS). Depending on the rubbing conditions, the boundary friction coefficient of the binary additive systems was found to be either lower than that of individual additives or to lay between the values for the individual additives. Chemical composition analysis of the tribofilms indicated that the nature of base oil controlled interactions between ZDDP and OFM and consequently adsorption and reactive tribofilm formation in the boundary lubri... Read More

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