Dependences of changes in the structural viscosity of oil films on the friction surface with fullerene compositions

In this work, the physical phenomenon of the formation of an oil film containing fullerenes was further developed, on the friction surface of tribosystems, which, in contrast to the known ones, takes into account the structural viscosity and structure of the formed film under the action of the electrostatic field of the friction surface. An increase in load significantly increases the structural viscosity of the gel structure, 13 - 20 times. The concentration of fullerenes in the base lubricant does not significantly affect the dynamic viscosity of aggregates in the composition of the liquid and the structure of the gel. An increase in the tribological properties of the base lubricant medium reduces the value of the structural viscosity of the gel on the friction surface by a factor of 3. At the same time, the concentration of fullerenes in the range of 0.5 - 1.5% does not have a large effect on these indicators. This phenomenon can be explained by the presence or absence of an additive package in the base lubricating medium. For those oils where the additive package is absent or present in a small amount J/m3, the introduction of a fullerene composition promotes the formation of clusters and micelles, which increase the structural viscosity and, consequently, form a film on the friction surface in the form of a gel structure. Conversely, if fullerenes are introduced into a base oil that contains a large and balanced additive package, where tribological properties are high J/m3, interaction at the molecular level does not occur. Fullerenes to a lesser extent will form stable aggregates in the form of micelles. The effect of reducing the coefficient of friction, equal to 96 %, is typical for low and medium loads of operation of tribosystems and base lubricants with average values of tribological properties. With increasing loads or tribological properties of base oils, the effect of the use of fullerenes decreases.

Development of oil industry in Azerbaijan

Considering the naphthenic-paraffin nature of the oil fractions of Balakhany oil, the paper presents the results of studies on the use of fully and partially dearomatized oil fractions of this oil as base oils, as well as their use in a mixture with base hydrocracked oil – VHVI, used in amounts of 25-50 %. The PMR spectra of the starting and obtained oils were recorded. The possibility of obtaining semi-synthetic high-stability motor oil SAE 15W-40 by using a mixture of T-46 and high-index hydrocracking oil (VHVI-4) 68 % (T-46 – 65 % + VHVI-4 – 35 %) + additive package was shown Lubrizol – 32 %, which is not inferior in antioxidant properties to the semi-synthetic oil SAE15W-40, containing as a base component a mixture of T-46 oils – 40 % + hydrocracking VHVI-4 – 32 % + selective oil SN-600 – 20 % + package additives of Belarus, as well as pure synthetic oil SAE 15W-40, containing SN-180 – 38 %, VHVI-4 – 27 % concentrate + Lubrizol – 35 %.

On the Fictitious Grease Lubrication Performance in a Four-Ball Tester

The extreme pressure (EP) behavior of grease is related to its additives that can prevent seizure. However, in this study following ASTM D2596 four-ball test method, the EP behavior of greases was modified without any changes to its additive package. A four-ball tester with position encoders and variable frequency drive system was used to control the speed ramp up time or delay in motor speed to demonstrate higher grease weld load and lower grease friction that were fictitious. A tenth of a second delay in speed ramp up time had showed an increase in the weld load from 7848 N to 9810 N for grease X and 6082 N to 9810 N for grease Y. Further increase in the speed ramp up time to 0.95 s showed that the greases passed the maximum load of 9810 N that was possible in the four-ball tester without seizure. The mechanism can be related to the delay in rise of local temperature to reach the melting point of steel required for full seizure or welding, that was theoretically attributed to an increase in heat loss as the speed ramp-up time was increased. Furthermore, the speed ramp up time increased the corrected load for grease X and Y. This resulted in lower friction for grease X and Y. This fictitious low friction can be attributed to decrease in surface roughness at higher extreme pressure or higher corrected load. This study suggests that speed ramp up time is a critical factor that should be further investigated by ASTM and grease manufacturers, to prevent the use of grease with fictitious EP behavior.

TECHNOLOGY FOR PRODUCING M10DM OIL BASED ON OIL DISTILLATES FERGHANA OIL PROCESSING PLANT (FOPP)

A technology for producing M-10 DM engine oil using the K-471 n. additive package has been developed, which provides high performance characteristics. KEY WORDS: additives, oil, raw materials, additive, resin, phenols.

Influence of cetane-detergent additives into diesel fuel with RME content increased to 10% on the parameters of indicator diagrams and rate of heat release in a diesel engine

This publication is the next part of the article “The influence of cetane-detergent additives in diesel fuel increased to 10% of RME content on energy parameters and exhaust gas composition of a diesel engine”. The cause-effect analysis of the phenomena related to the impact of 3 additive packages used in diesel oil with RME content increased to 10% (compare to standard diesel fuel with 7% of RME) was described. The basis for the analysis of the impact of the tested fuels on energy parameters and composition of exhaust gases were the parameters of indicator diagrams and heat release parameters. It was found that the first set of additives affects the delay of auto-ignition of fuel and kinetic fuel combustion speed only at low engine loads. In this range of engine operation the NOx concentration in the exhaust gas is low and besides there is a large of EGR.The second additive package was operated at high engine loads but its impact on the lower self-ignition delay was quantitatively small. Therefore, in the third packet of additives, the amount of additives used in the second packet was doubled. Then a satisfactory shortening of the self-ignition delay and reduction of the max rate of kinematic heat release was achieved as a reason of a reduction of NOx concentration in the exhaust up to 8% (compared to the reference fuel).

SERVICEABILITIES AND IDENTIFICATION OF CARBOXYL-CONTAINING ANTIFREEZING AGENTS

All major types of cooling liquids for motor vehicles are describes herein. Various liquids are used to cool internal-combustion engines. Water is the best cooling liquid in the warm season, when the air temperature is above 00С. Liquids with a low freezing point, namely antifreeze agents are used at temperatures below 00С. Low-freezing coolants – antifreeze agents are prepared by mixing water with one or more components that have the ability to lower the freezing point of the solution. The best low-freezing coolants are mixtures of water with glycols – ethylene glycol and propylene glycol. An additive package is added to the antifreeze compound to improve performance. Depending on the nature of the additives, modern antifreeze agents are divided into three types: traditional, carboxylate and hybrid. Traditional antifreeze agents (”tosol cooling agent” and modifications) contain inorganic additives and have a small (no more than 2 years) service life, while they do not stand high (more than 1080C) temperatures. According to the classification of the Volkswagen Audi Group proposed by the group of companies, traditional antifreezes with inorganic additives are designated with symbol G11. Hybrid antifreeze agents (G11+) contain organic and inorganic inhibitors (usually silicates or phosphates). Their service life is up to 3 years. Carboxylate antifreeze agents (G12) contains corrosion inhibitors based on salts of higher carboxylic acids (carboxylates). Carboxylate antifreezes obtain the longest operating life of up to 5 years. When conducting operational tests of various types of antifreeze agents for compliance with the requirements of National State Standard 28084-89 (СТ СЭВ 2130-80), “Low-freezing cooling liquids. General technical specifications” it was found that carboxylate antifreezes are inert to products (automobile radiators) made of aluminum and aluminum alloys, while traditional and hybrid antifreezes have a corrosive effect on aluminum and its alloys. An urgent task in the study of cooling fluids for motor vehicles is the establishment of the nature of additives. For the identification of carboxylate additives in antifreeze agents, it has been proposed to use the method of molecular spectroscopy in the infrared region of the spectrum. For the study, evaporated samples of antifreeze agents are used. Carboxylate additives are characterized by the presence of absorption bands caused by vibrations of carboxyl groups (COOH) at 1560 cm-1 to 1580 cm-1. The abovementioned absorption bands are not typical for traditional (G11) and hybrid (G11+) antifreeze agents and can be used to identify carboxylate additives in the composition of cooling liquids. This makes it possible to differentiate antifreeze agents by species. Key words: automobile antifreeze, operational properties, identification, spectral method.

Valorisation of used automotive lubrication oil

This study has explored the production of Light Oil 10 (LO10) fuel from used automotive lubrication oil, thus providing a method for producing a cheaper alternative to diesel and paraffin for the South African industrial heating fuel market. Used automotive lubrication oil has different physical properties to that of the specified properties for Light Oil 10 fuel and therefore has to undergo processing that aligns the properties of the two. The low availability of Light Oil 10 fuel in the South African industrial heating market is driving companies such as a Durban based oil refinery to develop a continuous process that will produce Light Oil 10 fuels without the supplementation of paraffin. The supplementation has been done to retain customers but this resulted in the company selling Light Oil 10 fuel at a loss. Used automotive lubrication oil was of particular interest for use as the raw material for the new process as it is of low cost and is readily available. The viscosity (a measure of how easily a fluid flows at a particular temperature) of used lubrication oil was too high and needed to be reduced before it could qualify as Light Oil 10. The reduction of the viscosity of a fluid means that the ability of the fluid to flow at a particular temperature has improved. Additionally the additive package and the impurity content of the used automotive oil were too high. The additive package is added to mineral oil to give it the properties that new automotive lubrication oil requires; this package is still present in used automotive lubrication oil and is responsible for the high level of impurity content because it prevents impurities from agglomerating and dropping out of the oil. The new process was therefore required to be able to reduce the viscosity of used automotive lubrication oil and break the additive package. The required process and operating variables were developed / identified through literature review (qualitative) and the optimum operating variables were identified through experimentation (quantitative). A design of experiment was carried out using Design Expert software. This identified the matrix of runs that were required in identifying the optimum temperature, pressure and residence time for the ranges specified. The product from each of the runs was analysed in the Durban based oil refinery Research and Development lab. The results from the lab along with the corresponding run conditions were used to develop a model, and the model used to identify the optimum operating conditions. The research and experimentation took a total of two years to complete. The literature review found an existing refinery process, the drum type visbreaker to be the most suitable process for reducing the viscosity and breaking the additive package of used automotive lubrication oil. The drum type visbreaker holds oil in the drum for a period of time known as the residence time, at temperatures and pressures of 443oC and 15 bar respectively. These three variables are the critical operating variables in the visbreaking process. The high temperature breaks the large molecules into smaller molecules thereby reducing the viscosity via a process known as thermal cracking. This process also breaks down the additive package. The results from the experimental runs revealed that it is possible to produce Light Oil 10 from used automotive lubrication oil using the drum type visbreaker. The model produced through experimentation was found to be reliable and accurate within the range of variables investigated at predicting results for future runs. The model was also successfully used to identify the optimum operating conditions at which Light Oil 10 is produced from used automotive lubrication oil. The conditions were found to be 475oC, 15 bar and 60 minutes, confirmed by three confirmation runs. In conclusion this study has identified through literature and experimentation that thermal cracking via the free radical mechanism is the preferred process for producing Light Oil 10 from used automotive lubrication oil at liquid yields greater than 90%. An appropriate model was generated using the critical operating variables to predict future viscosity results. It was recommended that the Durban based oil refinery design and build a production scale pilot plant that includes all equipment and the feed heating coil (furnace used to heat feed to 475oC) that a full scale plant would have. This is because the run lengths due to coking (build up of hard carbon on the surfaces of heat exchange equipment) and functionality of the process need to be confirmed before the process can be deemed to be economically viable. Once this has been achieved a full scale production facility can be built.

MoDTC Tribochemistry in Steel/Steel and Steel/Diamond-Like-Carbon Systems Lubricated With Model Lubricants and Fully Formulated Engine Oils

This work focuses on the tribochemistry of molybdenum dithiocarbamate (MoDTC) oil additive to improve friction behavior of diamond-like-carbon (DLC) coated systems lubricated in boundary regime. Raman microscopy has been used to investigate surface tribolayers formed on coated (hydrogenated a-C:H and non-hydrogenated ta-C) and steel surfaces when lubricated with model lubricants and commercial engine oils. The effect of the additive package and the type of DLC played a crucial role in the development and composition of the tribolayer and the friction performance. The additive package contained in the fully formulated (FF) oils limited the friction reduction capabilities of MoDTC additive for every material pair. Accelerated a-C:H coating wear related to MoDTC tribochemistry was found. For the first time, it has been shown that a distinctive MoS2-containing tribolayer can be formed on the ta-C surface, leading to a coefficient of friction lower than 0.04. The underlying mechanisms of MoDTC/surface interactions and their effect on friction and wear are discussed.

Friction and Wear Reduction Mechanisms of the Reciprocating Contact Interfaces Using Nanolubricant Under Different Loads and Speeds

This study aims to reveal the roles and mechanisms of Al2O3/TiO2 hybrid nanoparticles into the lube oils which could reinforce engine components durability via reducing the friction, wear, or fuel economy in automotive engines. The tribological tests were carried out under different sliding speeds from 0.21 to 1.75 m/s and loads from 30 to 250 N using a reciprocating tribometer to simulate the ring/liner interface in the engine according to ASTM G181. The tribological results using hybrid nanolubricants suggested that the friction coefficient and wear rate of the ring decreased in the ranges 39–53% and 25–33%, respectively, compared to nanoparticles-free lube oil. The combined evidence of the worn surfaces analysis confirmed that the key mechanisms in antifriction and antiwear are a combination of the nanoparticles rolling mechanism and the replenishment mechanism of tribofilms on the sliding contact interfaces. In addition, a tribofilm formed on the rubbing surfaces is not only from the nanoparticles but also from Fe which is formed as a result of iron debris particles and oil additive package such as P and S originating from zinc dialkyldithiophosphate.

The effects of surface conditioning and gear oil type on friction and wear behavior under sliding condition

Highly additized low viscous lubricants, new coatings, and surface treatments have been employed by original equipment manufacturers in several tribosystems to reduce emission and fuel consumption. In this sense, this work investigates the tribological response of four different advanced fully formulated gear oils and three different materials (coatings and topography) in terms of friction and wear using a ball-on-disc test rig under pure unidirectional sliding condition and boundary lubrication. The tested lubricants had different base oils: mineral, semi-synthetic, and synthetic with different additive packages. The ball's material was AISI 52100 bearing steel and the bulk material of the tested specimens (discs) were SAE 4320 steel with surface as follows: (i) ground; (ii) subjected to ceramic shot peening (CSP) and, (iii) coated with WC/C. Optical and scanning electron microscopy and 3D profilometry were used to evaluate the wear track and tribofilm formation. It was found that the frictional dependence on the surface topography and lubricant type is not significant, whilst the wear mechanisms were highly dependent on material and surface conditioning. The harder and rougher the contact body, the higher the wear produced in the counter body. At the harsher conditions base oil type control wear more effectively than the additive package.