Lubrication Engineers Research Articles

Friction Coefficient Dynamics of Tribological Coatings from Engine Lubricants: Analysis and Interpretation

Even today, there is no full understanding of the relationship between the physical, chemical, and mechanical properties and the behavior of the lubricating films formed in tribological systems. Most of the published scientific research measures and reports the overall values of friction and wear, but the information given via statistical signals in the tribological tests is, in general, dismissed, leaving a hole in the study of the dynamics of tribological systems. In this work, an experimental study of statistical friction data, coating characteristics, and tribological performance is carried out using a pin-on-disk tribometer to test some metallic samples coated with lubricant films under several experimental conditions. The results indicate that long deposition times at high deposition temperatures of coatings from engine oil develop low-friction intervals, which fall until 20% of the uncoated coefficient friction. However, an unexpected and unfavorable behavior of the coatings was observed for the short deposition times and high temperature. In these conditions, the developed friction profiles reached a maximum level of friction that was 20% more than the uncoated coefficient friction. Moreover, it was found that the proper analysis and interpretation of the statistical data, in combination with the characterization of the coatings, describes the dynamics of the interactions between the bodies in contact and reveals the transitions of the surfaces with non-homogeneous properties throughout their depth.

Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen. Part 2: Effect of operating conditions

The need to cope with carbon dioxide abatement has prompted the development of innovative technologies for sustainable mobility. Meanwhile, these technologies consolidate, an important role will be played by internal combustion engines fed with non-fossil fuels such as hydrogen. Theoretically, the combustion of hydrogen should not produce carbon-based emissions. Nevertheless, particles can be found in the exhaust of hydrogen-fueled engines because of the lubricating oil. In this study, a thorough examination of the impact of the engine lubricant on the mechanisms leading to the formation of the particles and the high levels of hazardous pollutants was performed in this study. Experiments were carried out on a direct injection spark ignition engine fueled with hydrogen. The analysis was conducted at 2000 and 3000 rpm both low and full load. Number and size particle distribution were determined by means of on-line measurement on the diluted exhaust. Off-line chemical characterization through analytic techniques was realized on the condensed exhaust and on the particles collected on a filter. Experimental results pointed out that the extent of the particle size varies according to the engine speed and load, evidencing the different role of the oil ascribable to the environmental conditions. It was found that aromatic molecules and nanoparticles are present in the exhausts at all the investigated operating conditions, whereas soot aggregates are formed only at high engine speed.

Evaluation of tribological properties and sustainability of bio-lubricant developed from neem seed oil for real-life application

The Tribological property of Neem seed oil is evaluated with various proportions of Zinc Dialkyl Dithiophosphate (ZDDP) ranging from 0.5% to 3% by weight and compared with SAE 20W40 oil. The best weight percentage concentration of the additive with the base oil was selected for further property analysis. The formulated bio lubricant is tested on real-life application as engine lubricant on a working motorbike engine to arrive at the feasibility of these oils as a practical engine oil. The biodegradability and toxicity of the best additive concentration were evaluated. The study showed that the addition of 2% ZDDP increased the anti-wear properties of the base oil and it was found comparable to industrial standard oil after the engine run test.

Wear evaluation of palm oil and SAE 15W 40 engine lubricants with a ball-on-disk tester based on an improvised drilling machine

This paper introduces a modified ball-on-disk test, utilizing a drilling machine, to investigate the tribological behavior of wear on a plate surface under various lubrication conditions. The tribometer, based on the ball-on-disc principle, employs an improvised bench-top drill press machine. Despite its simplicity, it effectively facilitates wear-track experiments using engine oil (SAE 15W 40) and palm oil as lubricants. Tests are conducted at room temperature, maintaining a constant load at 8.83 N and rotational speed of 180 rpm for 2 minutes per sample. Microscopic analysis of wear scars on the plate samples reveals distinct wear patterns and characteristics for each lubricant, with measurements taken at multiple positions for accuracy. The current work focuses exclusively on wear scar analysis, with findings indicating that engine oil outperforms the counterpart, displaying a smaller wear track width, hence superior lubrication and wear protection capabilities. In contrast, palm oil exhibits a larger wear track, implying limitations in friction reduction and material preservation. This work has demonstrated the practical use of the cost-effective tribometer device for conducting preliminary studies of lubricant wear reduction performance. The test outcomes render valuable insights for lubricant formulators, particularly at the early stage of laboratory-scale development.

Analysis of Sound Emission Using Ternary Blend Fuel in Compression Ignition Engine

Alternative fuel is considered to be suitable oils in diesel engines, which are well known for their ability to diminish lubricant oil debris and noise emissions. A minute research has been done to examine the long-term effects of using blend fuel. In this study, two blend fuels: diesel and waste cooking oil (DF95WCO5), and diesel, waste cooking oil and n-pentanol (DF65WCO20Pe15) were chosen and compared with diesel fuel (DF) to investigate the impact of these blends on noise emission in diesel engine. In order to evaluate the kinematic viscosity and density and determine the effect on sound pressure levels, lubrication oil samples were taken throughout the test at intervals of 20 hours. A literature review was done for the current work's analysis of the literature on the noise emissions from diesel-waste cooking and n-pentanol fuel blends. When the engine was fueled with DF65WCO20Pe15 blend, the engine lubricating oil analysis revealed an extreme wear issue, decreased viscosity, and increased density values. The conclusion is that single cylinder diesel engines can use binary blend DF95WCO5 and ternary blend DF65WCO20Pe15 without any adjustments. DF65WCO20Pe15, in contrast to the reference fuel, achieved some superior outcomes.

OPERATING TESTS OF THE DEVICE FOR ELECTROSTATIC ENGINE OIL TREATMENT

The article presents the results of preliminary studies aimed at establishing the main factors affecting the service life of sliding bearings. The researchers pay special attention to the dominant types of lubrication, the thickness of the lubricating film, the load-bearing capacity of the film, shear resistance during friction, as well as the aging of the oil and the loss of its properties over time. Taking into account the previous achievements, as well as the works of the authors in the direction of increasing the wear resistance and resource of sliding bearings, it is proposed to test the sliding bearings of the D-240 diesel engine on the SMC-2 friction machine. The tests were performed according to the "pad - roller" scheme. In this diagram, the roller simulates the neck of the crankshaft, it is made of HF cast iron. The pad presses against the roller a fragment of the liner, which was made from a real engine liner and is a bimetallic element with a steel base and an antifriction coating of AO-20-1 alloy. In the tests, the sliding friction of the liner fragment on the roller was modeled, and the load modes of the friction pair were set in such a way that mixed lubrication of the bearing or transitional lubrication from limit to hydrodynamic lubrication is achieved. The purpose of the tests was to establish the regularities of the impact of engine oil aging and its electrical processing on the wear resistance and service life of the bearing liners. For this, oil samples were taken from the engine lubrication system. Oil samples with 0, 150, 300 engine hours were tested. The complete experiment consisted of two series of trials. The first series of tests concerned the establishment of the effect of working on the wear resistance when lubricating the bearing with traditional oil taken from the engine. The second similar series of tests included the additional introduction of electrical treatment of the oil samples before it was fed to the bearing model. The values of weight wear of liner fragments were obtained experimentally. The wear resistance and service life of the liners were calculated according to the corresponding dependencies, which are also given in the article. As a result of measurements and calculations, the regularities of the effect of working on the conditional life of the liners were obtained, taking into account the effect of the electrical treatment of the oil.

Experimental Wear Analysis of Nano-Sized Titania Particles as Additives in Automotive Lubricants

This study focuses on the wear effects of nano-sized titania as a potential engine lubricant additive. Titanium dioxide nanoparticles have promising wear-reducing properties and significant tribological potential. In this article, titania nanoparticles were homogenized in Group III automotive oil at five different concentrations (0.1; 0.2 … 0.5 wt%). The nanodoped oil samples were tested on a linear oscillating tribometer with oil circulation. Based on the tribological results, titania nanoparticles increased friction by 20–32% but can reduce the wear area by up to 32%. According to the confocal microscopic examination, wear volume can be reduced by up to 57% with titania nanoparticles. Titania nanoparticles improved the repeatability of tribological measurements. A scanning electron microscopy examination of the wear track revealed that the characteristic wear of the tribological system was abrasive, but a significant amount of adhesive wear was also observed. Energy dispersive X-ray spectroscopy analysis found that the nanoparticles fill the deeper trenches of the wear. The worn surface uniformly contains TiO2 particles and the quantified normalized titanium concentration was between 0.56 and 0.62%.

Emission and Lubrication Performance of Hazelnut Oil as A Lubricant

The aim of this study is to search the tribological and emission performances of hazelnut oil as a lubricant in one cylinder two-stroke gasoline engine and simulation-testing machine. The tribological and emission performances of mineral oil and hazelnut oil as lubricant were compared. In the experiments, simulation-testing machine and one cylinder two-stroke gasoline engine were used to determine the tribological performance of these two lubricants. The wears on the surfaces of cylinder were analyzed to examine the lubricant performances. In addition to lubrication performance, exhaust emissions of the lubricants were also measured. To observe the effects of different kinds of cylinder surface materials, TiN, CrN and gray cast iron coated cylinder surfaces were used in simulation testing machine. The wear as well as the soot formation on the cylinder surfaces increased when hazelnut oil was used as the engine lubricant. However, hazelnut oil exhibited good lubrication properties in simulation testing machine. When hazelnut oil was used, CO and HC emissions increased while CO2 emission decreased.

Tribological Investigation of the Effect of Nanosized Transition Metal Oxides on a Base Oil Containing Overbased Calcium Sulfonate

In this study, copper(II) oxide, titanium dioxide and yttrium(III) oxide nanoparticles were added to Group III-type base oil formulated with overbased calcium sulfonate. The nanosized oxides were treated with ethyl oleate surface modification. The tribological properties of the homogenized oil samples were tested on a linear oscillating tribometer. Friction was continuously monitored during the tribological tests. A surface analysis was performed on the worn samples: the amount of wear was determined using a digital optical and confocal microscope. The type of wear was examined with a scanning electron microscope, while the additives adhered to the surface were examined with energy-dispersive X-ray spectroscopy. From the results of the measurements, it can be concluded that the surface-modified nanoparticles worked well with the overbased calcium sulfonate and significantly reduced both wear and friction. In the present tribology system, the optimal concentration of all three oxide ceramic nanoadditives is 0.4 wt%. By using oxide nanoparticles, friction can be reduced by up to 15% and the wear volume by up to 77%. Overbased calcium sulfonate and oxide ceramic nanoparticles together form a lower friction anti-wear boundary layer on the worn surfaces. The results of the tests represent another step toward the applicability of these nanoparticles in commercial engine lubricants. It is advisable to further investigate the possibility of formulating nanoparticles into the oil.

Ambient temperature impact on the parameters of the electrical circuit of sensing element in cluster eddy current sensor of metal chips in the lubrication systems of gas turbine engines

The detection of the wear particles in the engines lubrication systems is one of the most effective ways to assess the state of the bearing assemblies of machines and mechanisms. The most promising existing systems for online monitoring of wear particles are based on the eddy current methods for monitored parameters conversion. The reason is that such systems have the ability not only to determine the particle size, but also to recognize its magnetic properties, which makes it possible (under certain conditions) to localize the place of the defect development. At the same time, it is known that the ambient temperature changes in the monitored zone are one of the main external factors that have a significant impact on the informative parameters of eddy current converters. This is of particular importance for debris monitoring systems in high-power plants lubrication systems (e.g. gas turbine engine), where the oil temperature can vary widely (-50...+160 C). The temperature impact on the parameters of the electrical circuit of sensing element in the cluster single-coil eddy current sensor of metal chips, which is a part of the debris continuous monitoring system prototype for high-thrust aviation gas turbine engine, is studied in the article. A typical design of the single-coil sensing element is considered. The study results of the temperature effect on the sensing element inductance, as well as on the parameters of the current lead that connects the sensing element to the matching transformer and to the measuring circuit are presented. Methods for reducing the impact of temperature changes in the monitored area on the parameters of the electrical circuit of the sensing element are proposed, too.

Experimental investigation of the effects of boron oil additive in internal combustion engine

Using additives to engine oils increases engine performance, extending engine maintenance life, boosting the competitiveness of mineral-based oils technically and economically. In this study, the effects of liquid boron oil additive added to mineral-based 10 W-40 engine lubricating oil used in a single-cylinder diesel engine were investigated. 15 % of the engine oil volume was added to the engine as an additive. Experimental studies were carried out at three different engine speeds (i.e., 1500, 1750, and 2000 rpm). The engine, on which no changes were made, was first run with mineral lubricating oil, and then the experiments were repeated with mineral lubricating oil with 15 % boron additive. In the studies, engine torques, specific fuel consumption, and exhaust emissions (HC, CO, CO2, and NOx) were evaluated. In addition, the effects of operating the engine for 100 h without adding any additives and with oil additives containing 15 % boron were also investigated. It was found that engine torque and EGT increased while BSFC, CO2, HC, and NOx decreased in boron-added mineral lubricating oil for all revolutions. In addition, there was a general decrease in CO emissions. In-cylinder SEM images and oil analyses, which were operated with a 15 % boron additive to the engine oil, showed that the boron additive positively affected the engine.

Synthesis, characterization and tribological investigation of vegetable oil methyl esters based bio-lubricants

The lubricating ability of vegetable oil-based lubricant additives with commercially used engine lubricant is investigated in this article. The methyl esters of Neem, Pongamia and Tamanu oils were formulated by transesterification process and blended with SAE20W40 oil in 10%, 20% and 30% of its volume. These biolubricant blends were tested for physiochemical properties and tribological behavior using LM13 Aluminium alloy as the pin material in accordance with ASTM standards. Experimental outcomes established that the biolubricant blends like N10, P10, P20, N20 are capable of reducing wear about 77%, 52%, 92%, 81% respectively and the frictional coefficients of N10, P20 and T30 were found to be appreciable. In the long run, they can be used as primary alternatives to conventional lubricants.

Current Knowledge on Friction, Lubrication, and Wear of Ethanol-Fuelled Engines—A Review

The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tribological challenges to the engine. This review addresses the current state-of-the-art on the effects of ethanol fuel on friction, lubrication, and wear in car engines, and identifies knowledge gaps and trends in lubricants for ethanol-fuelled engines. This review shows that ethanol affects friction and wear in many ways, for example, by reducing lubricant viscosity, which on the one hand can reduce shear losses under full film lubrication, but on the other can increase asperity contact under mixed lubrication. Therefore, ethanol can either reduce or increase engine friction depending on the driving conditions, engine temperature, amount of diluted ethanol in the lubricant, lubricant type, etc. Ethanol increases corrosion and affects tribocorrosion, with significant effects on engine wear. Moreover, ethanol strongly interacts with the lubricant’s additives, affecting friction and wear under boundary lubrication conditions. Regarding the anti-wear additive ZDDP, ethanol leads to thinner tribofilms with modified chemical structure, in particular shorter phosphates and increased amount of iron sulphides and oxides, thereby reducing their anti-wear protection. Tribofilms formed from Mo-DTC friction modifier are affected as well, compromising the formation of low-friction MoS2 tribofilms; however, ethanol is beneficial for the tribological behaviour of organic friction modifiers. Although the oil industry has implemented small changes in oil formulation to ensure the proper operation of ethanol-fuelled engines, there is a lack of research aiming to optimize lubricant formulation to maximize ethanol-fuelled engine performance. The findings of this review should shed light towards improved oil formulation as well as on the selection of materials and surface engineering techniques to mitigate the most pressing problems.

Evaluation of optimal time blending process on medripal 412 And Prima XP SAE 20W – 50 samples with homogenity test

Prima XP SAE 20W - 50 is a multigrade lubricant used for gasoline and Medripal 412 engine lubricants used for marine industry engines which are non-carcinogenic and environmentally friendly. The main factor in testing lubricants is the Blending process, which is the process of mixing base oil with additives. In the blending process, an inhomogeneous lubricant was found which caused the lubricant test not to comply with specifications. This experiment aims to determine the optimal time of the blending process with the KAN homogeneity test method. Homogeneity testing can be seen from the viscosity value of the lubricant. So the optimum time for the blending process is needed for the continuity of the production process of this lubricant. Medripal 412 products have an optimum blending time of 30 minutes with a viscosity value at 100 C ranging from 14.79 mm2 / s based on the SNI 7069.1 Th. 2012, the product specification value of Medripal 412 is 12.5 - <16.3 mm2 / s and the Prima XP SAE 20W - 50 product has an optimum blending time of 45 minutes with a viscosity value at 100oC of 20.28 mm2 / s based on the SNI 7069.1 Th. 2012, the value of the Prima XP SAE 20W - 50 product specification is 5.6 - <21.9 mm2 / s. This shows that the lubricant is by the standard quality standards set by the company and the government so that the lubricant product is still suitable for use.

Influence of oil service life on selected performance parameters of an aircraft piston engine

This article presents an analysis of the influence of oil service life on the performance parameters of an aircraft piston engine lubrication system used in an ultralight aircraft. The ageing of oil between oil changes causes a change in its parameters (such as density, viscosity ...). These parameters have a strong influence on the level of protection of the lubricated components. Currently, in aircraft, oil changes are carried out according to a time schedule - oil is changed every fixed period (residual life) regardless of its actual condition. The task of this article is to test the possibility of indirect assessment of oil condition based on analysis of changes in selected parameters of engine lubrication system operation during normal operation. The oil warm-up speed during the pre-start procedure and the dependence of oil pressure on engine speed were assumed for the analysis. The study was conducted on an ultralight rotorcraft during normal operation. Selected first daily flights directly after oil change, and after 17, 32, 50, 66 hours of operation were analysed. It was shown that the warm-up rate changes in the samples analyzed, but that this change may also be due to factors other than oil operating time. In the case of the oil pressure vs. speed characteristics, different characteristics were shown for different operating time, but no specific dependencies were found.

Classification, Structure, Biomedical Properties

Key words: surfactants, hydrophilic group, hydrophobic chain, dimeric (two-centered) surfactants, intrinsic toxicity, spacer Surfactants make it possible for soap to mix with water by lowering the water surface tension. Beyond soaps and detergents, surfactants are used in lubricants, inks, anti-fogging liquids, herbicides, adhesives, emulsifiers and fabric softeners. Surfactants added to cleaning agents, allow the detergent to mix into water, helping cleaning agents remove dirt from the cleaned surface. Without surfactants, soaps wouldn’t mix with the water, making the cleaning process much more difficult. Surfactants are also used as an ingredient in lubricants, such as shaving cream, which make it easier to remove stubble and help limit irritation. Surfactants added to car engine lubricants help keep particles from sticking to engine parts, allowing the parts to move easily and keep a car in proper running order. The uses of Surfactants are far broader than those that have been described above; therefore, having such a large-scale application in the industry and everyday life, in this work we will present the main types of Surfactants, their applications, development prospects and their impact on the human body and the environment. As a result, it is important to note that amino acid-based 2-centered Surfactants are of the most interest and have great development potential among the newest Surfactants. The use of dicenter Surfactants synthesized from amino acids is increasing in the production of cosmetics, pharmaceuticals, and biomedical products, mainly because they are less toxic, environmentally friendly, and actively biodegradable. In general, amino acid-based dicenter Surfactants are promising compounds for biomedical applications and many exhibit a broad spectrum of antimicrobial activity while being non-cytotoxic.

Multiphysics performance assessment of hydrogen fuelled engines

In the quest for decarbonisation, alternative clean fuels for propulsion systems are sought. There is definite advantage in retaining the well-established principles of operation of combustion engines at the core of future developments with hydrogen as a fuel. Hydrogen is envisaged as a clean source of energy for propulsion of heavy and off-road vehicles, as well as in marine and construction sectors. A source of concern is the unexplored effect of hydrogen combustion on dilution and degradation of engine lubricants and their additives, and consequently upon tribology of engine contact conjunctions. These potential problems can adversely affect engine efficiency, durability, and operational integrity. Use of different fuels and their method of delivery, produces distinctive combustion characteristics that can affect the energy losses associated with in-cylinder components and their durability. Therefore, detailed predictive analysis should support the developments of such new generation of eco-friendly engines. Different fundamental physics underpin the various aspects of a pertinent detailed analysis. These include thermodynamics of combustion, in-cylinder tribological interactions of contacting surfaces, and blowby of generated gasses. This paper presents such an integrated multi-physics analysis of internal combustion engines with focus on hydrogen as the fuel. Such an in-depth and computationally efficient analysis has not hitherto been reported in the literature. The results show implications for lubricant degradation due to the use of hydrogen in the performance of in-cylinder components and the underlying physical principles.

Experimental Study on Dissolution Stability and Dispersion and their Influence on Tribological Properties for Reducing Friction and Prolonging Life of Armored Vehicle Engine Lubricating Oil Additives

A lubricating oil additive for armored vehicle engine was synthesized by ultrasonic dispersion and physical blending with polyisobutylene and poly alpha olefin as polymer matrix, nanoBN and nanoALN as antifriction materials and polyisobutylene succinimide as surfactant. Polymer-based lubricating oil additive, hydroxyl magnesium silicate powder additive, commercial anti-wear repairing agent Goldway and commercial anti-wear protective agent Chief were dispersed into 10W-40 armored vehicle engine special lubricating oil according to a certain mass fraction. The dissolution stability of different lubricating oil additives in lubricating oil was investigated by standing test. The effects of ultrasonic time and temperature on the dispersion of different kinds of lubricating oil additives in lubricating oil are investigated by using ultrasonic disperser and particle size analyzer. The MDW-5G multifunctional end-face friction and wear tester is used to simulate the actual working process of cylinder liner-piston ring in armored vehicles during driving, and tribological tests were carried out under conventional working conditions to evaluate the tribological properties of different lubricating oil additives. Scanning electron microscope was used to measure and analyze the wear surface morphology and friction interface elements after tribological test, and the lubrication mechanism of lubricating oil additives is revealed. The results show that the polymer-based lubricating oil additive has good dissolution stability and dispersion in lubricating oil. Compared with pure lubricating oil, the average friction coefficient of lubricating oil containing 3wt% polymer-based additives is 0.085, and the friction coefficient decreases by 38.8%. During the friction process, polymer-based lubricating oil additives form a self-repairing oil film to cover the surface of the sample through a series of complex physical and chemical reactions, which reduces the friction and wear between the grinding pairs and improves the lubricating performance of lubricating oil.

Developing Augmented Reality Learning and Measuring Its Effect on Independent Learning Compared to Traditional Learning

Technological advances have become the concern of researchers in the embodiment of the educational process. Current students have abandoned the old learning method by switching to digital-based learning. Therefore, this study aims to develop Android Augmented Reality (AR) learning media and measure its effect on independent learning outcomes compared to traditional classroom learning. The research method combines research and development (R&D), experiment, and survey methods. The alpha test showed the learning media application of AR functions according to the expected scenario. Meanwhile, the beta test showed most students strongly agree that: AR learning media is easy to use; the content in the AR learning media is exciting and easy to understand. Besides that AR education media helps and facilitates students in learning the basics of car engine systems. The beta test on teachers showed that AR learning media for car engine lubrication and cooling system is useful and suitable for classroom learning. Furthermore, the t-test comparison test shows that the learning outcomes of students who study independently are more successful when compared to the learning outcomes of AR students who study traditionally face-to-face.So the implication is student self-directed learning can replace the teacher's face-to-face classroom teaching.

Experimental Investigation of the Friction Modifying Effects of Graphene and C60 Fullerene Used as Nanoadditives in Engine Lubricating Oil Performed on an Oscillating Tribometer

The present article presents the results of tribological investigations performed on an off-the-shelf engine lubricant containing nanoadditives of multilayered graphene and C60 fullerene alternately. As anthropogenic CO2 is believed to be highly responsible for global climate change, its emission is regulated in many countries. CO2 emissions can be significantly decreased by improving the efficiency i.e. decreasing the losses in an engine. Hence reducing frictional losses was the ultimate scope of the investigations presented in this article. The experiments were carried out on an oscillating tribometer at the Department of Internal Combustion Engines at Széchenyi István University. The experiments showed that multilayered graphene in engine lubricant did not modify the friction coefficient inevitably (-1% to +4%). Fullerene nanoparticles, however, reduced the friction by 4–8%. The optimal fullerene doping quantity that resulted in the lowest friction showed to be at around 0.14 wt%.