Lubrication Efficiency Research Articles

Monitoring of oil lubrication limits, fuel consumption, and excess CO2 production on civilian vehicles in Mexico

The vehicle fleet in some regions of the world continues to age, so it is difficult to reduce the consumption of fuels, meet environmental objectives and mitigate the cost it represents. Studies exist regarding low mileage vehicles, yet it is important to know the effect generated by high mileage vehicles, which represents a higher percentage in the word. This work was based on the oil degradation. A maximum value of decrease in viscosity of 31% was found, from which the lubrication efficiency of the oil decreases. This also leads to a significant increase in gCO2/km and fuel consumption. In a deeper analysis of the Nissan Tsuru, we found an annual excess of 69.25 Lt of fuel consumption that produces 129.024 Kg additional of CO2 (12.18gCO2/km) with a cost of $1,414.08 Mexican pesos. Due to the average vehicle age in Mexico (15.3 years), these results can be taken as an average for the 45 million plus cars that are currently in circulation. Also, 5.806 million tons of CO2 are generated that represent 3.6% of all current emissions. This leads to a consumption of 3.11 billion liters of fuel at a cost of $63.63 billion Mexican pesos. This methodology can be generalized for different brands of cars and oils in countries with a vehicle fleet similar, in search of improving the monitoring and proper use of automotive oil. In addition, this provides information on the negative effects, so that the countries can establish procedures and strategies for compliance with low pollution policies.

Scuffing resistance of polyalphaolefin (PAO)-based nanolubricants with oleic acid (OA) and iron oxide nanoparticles

The development and application of nanolubricants has shown great potential to reduce friction and wear, especially in the automotive field for systems operating under boundary and mixed lubrication regimes. The search for additives that do not attack the environment has motivated the use of nanoparticles, especially metallic oxides, because of their characteristics such as low toxicity, high surface area, high wettability, and easy dispersion. The objective of this work was to evaluate the addition of iron oxide nanoparticles as additive to pure PAO 8 base oil. The nanoparticle action mechanisms, lubrication efficiency, friction, and wear rates were evaluated. The concentration of nanoparticles in the oil and the addition of oleic acid as a dispersing agent were varied. The synthesis of the nanoparticles was done by aqueous precipitation; characterization was performed by XRD, FTIR, Raman and SEM analyses. Tribological tests were performed in a reciprocating tribometer (Plint TE 67) using AISI 1020 prismatic samples and AISI 52100 chrome steel balls of 5 mm diameter. Test conditions resulted in boundary lubrication regime, for a starved contact with limited lubricant supply (0.5 µL). Concentrations of 0.4 and 1.6 wt% of nanoparticles were added to the base oil with and without the presence of oleic acid. Friction coefficient was not sensitive to the presence of nanoparticles, with statistically similar values for all the fluids tested. On the other hand, the presence of nanoparticles increased scuffing resistance and reduced wear rates. The lubricants with nanoparticles proved able to withstand relatively high loads, keeping the friction coefficient low for longer test durations due to the formation of protective tribolayers between the worn surfaces. The addition of nanoparticles reduced wear rates by around 27% when compared to tests using pure PAO 8.

Assessment of the Tribological Properties of the Steel/Polymer/Steel Sandwich Material LITECOR

The article presents the results of tribological investigations into the steel/polymer/steel sandwich material LITECOR® developed by ThyssenKrupp Steel Europe for applications in the automotive industry. Friction tests were carried out by means of a strip drawing test with the use of a special tribotester mounted on a uniaxial tensile test machine. The influence of sheet deformation on the value of the coefficient of friction (COF) was considered. For this purpose, the samples were subjected to a pre-deformation of 4%, 8% and 12%. Friction tests were carried out with different force values and under different friction conditions, i.e., in dry friction conditions and lubrication of the sheet surface with L-AN 46 machine oil. The highest values of COF were observed for as-received sheets. In contrast, apart from the friction process under the conditions of the lowest force analysed, the lowest value of the COF was observed for pre-strained sheets with a deformation of 12%. The lubrication efficiency of the pre-strained strip specimens with ε = 4% was between 10.5% and 16.3%, with a trend of increasing lubrication efficiency with increasing force. For pre-strained sheets with deformation ε = 12%, there was a trend of decreasing effectiveness from 14.9% to 9.03% with an increase in force.

A novel tool to enhance the lubricant efficiency on induction heat-assisted incremental sheet forming of Ti-6Al-4 V sheets

For heat-assisted single point incremental sheet forming (SPIF) works of Ti-6Al-4 V sheets, the use of lubricant has shown significant effects on surface quality and geometric accuracy at higher temperatures. Molybdenum disulphide (MoS2) is a common lubricant widely used in SPIF works, however, it usually indicates ineffective performance at high temperatures. This article has studied different lubricants of MoS2 lubricants and proposed a novel mixture of MoS2 to provide better surface quality and improve geometric accuracy. A forming tool with a ball-roller and water channel was designed to enable the MoS2 mixture to pass through the tool tip, allowing easy application of the lubricant on the localised area and reduce the thermal expansion on the ball-roller. Surface roughness analysis has revealed that the water-cooling MoS2 mixture performed well in reducing friction effects and achieved better geometric accuracy. Forming forces measurements, scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX) and micro-hardness tests also indicated that a higher strain hardening behaviour was detected for the water-cooling MoS2 mixture.

Reducer lubrication optimization with an optimization spiking neural P system

It is very difficult to improve the efficiency and accuracy of reducer lubrication due to the limitation of the traditional simulation method. In this paper, an optimization model with multiple parameters is first established to reflect the relationship between the churning loss and the optimized parameters of the zero-backlash high-precision roller developing reducer (ZHPRER). Then, an optimization spiking neural P system (OSNPS) is applied to optimize the multiparameter model. Finally, a simulation analysis (the semi-implicit moving particle method, MPS) is used to verify the correctness of the optimization results. The experimental results show that the multiparameter optimization model and OSNPS are effective and accurate for solving the multiparameter optimization problem of ZHPRER by MPS method.

Effect of Surface Texture on the Sliding Pair Lubrication Efficiency

The paper presents certain problems related to the lubrication of textured surfaces. It was noted that for a specific load, the lubrication effectiveness will depend on the shape, size and mutual distribution of the texture’s elements. Proposals for determining the lubrication irregularity parameters were presented for textures with a rectangular mesh and round recesses. The experimental part presents the laser texturing methodology, tribological testing methodology and preliminary test results where the significant role of the relationship between the trajectory of motion and the texture mesh was demonstrated.

Effect of Graphene Addition to Lithium-Based Grease on the Performance of Rolling Element Bearings

Recent research attempts have shown that graphene as a lubricant nanoadditive provides excellent tribological behaviour in mechanical applications due to its outstanding properties represented in its self-lubricating nature. In this work, a set of deep groove ball bearings lubricated using lithium-based grease mixed with different contents of reduced graphene oxide (rGO) were tested through a specially designed test rig under different loading conditions. The rGO additions were varied to include 0.5, 1, 2, 3.5, and 5 wt.%. The consumed power is introduced for the first time as a measure of lubrication efficiency. The results demonstrate that the addition of rGO reduces the consumed power required to drive the rotor under the applied test load. The most considerable power saving is obtained after adding 2wt.% rGO to grease, which has reduced the consumed power down to about one-fourth of that consumed using grease only. Also, the vibration levels were measured and analysed for each lubrication and loading condition.

Analysis of Grooves Used for Bearing Lubrication Efficiency Enhancement under Multiple Parameter Coupling

Adding axial groove structures to the surface of bearing inner ring is an effective way to enhance the bearing lubrication efficiency. In this paper, the angular contact ball bearing H7006C was taken as the research object, and through visual simulations and quantitative experiments, systematic analyses and discussions were carried out to find out the relationship between groove-enhancing performance and working conditions. Firstly, simulation models of standard bearing and groove-added bearing were established. By combining the Volume of Fluid (VOF) model, the enhancing mechanism of grooves was found. Secondly, the trend of groove-enhancing performance with the change of rotation speed was studied through simulations and quantitative experiments. On this basis, through multiple parameter coupling, the effects of oil supply amount and nozzle diameter on the groove performance were discussed. The results show that the bottom oil layer is the key for grooves to achieve the lubrication efficiency enhancement, and its distribution can reflect the groove-enhancing performance. The groove width that best adapts to the change of working conditions increases with the increase of oil supply amount and nozzle diameter. To maintain the stability of bottom oil layer, the nozzle diameter should be larger than the groove width. This research is of great significance to the application of grooves in the lubrication efficiency enhancement of high-speed bearing.

Polynomial Multiple Regression Analysis of the Lubrication Effectiveness of Deep Drawing Quality Steel Sheets by Eco-Friendly Vegetable Oils.

Ensuring adequate lubrication is a key task in the sheet metal forming process. The replacement of commonly used synthetic lubricants in metal forming operations by eco-friendly equivalents is a way to introduce sustainable manufacturing. In this paper, six kinds of vegetable oils (linseed, palm, sunflower, cotton seed, soybean and coconut) were used to study the effect of lubricant type on the value of the coefficient of friction (COF) in sheet metal forming. The strip drawing test was used to simulate the friction conditions. The tests were carried out for various lubrication conditions and pressures. The polynomial quadratic regression model was used to determine the relationship between the input variables (test conditions) and the COF. For the range of the nominal pressures considered (2–12 MPa), the following oils provided the highest lubrication efficiency: palm, sunflower and cotton seed. These oils decreased the value of the COF by about 11–16% depending on the nominal pressure. Linseed oil had the most unfavourable properties, reducing the COF by about 7–12%. For the whole range of pressures considered, the increase in the viscosity of the oil caused a reduction in the value of the COF. The effect of oil density on the COF value was similar. The most unfavourable friction conditions occurred when there was low density and low viscosity of the oil at the same time.

Lubrication-enhanced mechanisms of titanium alloy grinding using lecithin biolubricant

As a dielectric, biolubricant (vegetable oil) cannot maximize the efficiency of electrostatic atomization minimum quantity lubrication (EMQL). The lecithin-enhanced technology is expected to solve this technical bottleneck. The effects of lecithin on the electrophysiological properties of biolubricant (soybean oil) were investigated. Lecithin can increase the conductivity, viscosity, and charge mass ratio and reduce the surface tension of soybean oil. Comparative experiments show that the maximum average temperature rise of workpiece surface with MQL is 241.6 °C. The value under flooding, EMQL, and L+EMQL is reduced by 28.97%, 42.8%, and 48.92%, respectively, compared with MQL. The influence of lecithin mixing ratio on grinding performance was discussed. The minimum surface roughness value (0.49 µm) is obtained at the mixing ratio of 2:10.

ЗАЩИТА РЕЗЬБОВЫХ СОЕДИНЕНИЙ ОТ ТЕРМООКИСЛИТЕЛЬНОГО СХВАТЫВАНИЯ

Modern industry places a number of stringent requirements to the performance properties of fasteners. All fastening elements made of metal are subject to corrosion-mechanical wear. Their disassembling is a time-consuming process which is often accompanied by destruction of the part. Damage to threaded connections can be prevented by applying a special thread lubricant to the part. Based on theoretical and experimental research, the authors have developed a formulation of high-temperature thread compound “Udar”, which contains the following components: molybdenum disulphide (70 wt.%), titanium dioxide (3 wt.%), colloidal graphite compound (70 wt.%), aluminium (powder) (5 wt.%), OMIK “TELAZ” (10 wt.%), thickener (petrolatum), and industrial oil I-40A. The lubricant efficiency in protecting fasteners against atmospheric corrosion and corrosion setting was tested on six specimens representing a pair of “bolt-nut”. The results of comparative laboratory tests of the developed composition with foreign-made greases have shown that the developed thread lubricant is able to protect threaded joints from thermal-oxidative setting occurring at up to 9000C. Application of this composition will considerably reduce the equipment disassembling time due to reduction of the absolute value of torque when disassembling fasteners, and prevent thermochemical and corrosion “seizure” of threaded joints.

Analysis of the Friction Mechanisms of DC04 Steel Sheets in the Flat Strip Drawing Test

This article presents the use of a specially designed flat strip drawing tester in order to assess the change in surface topography of DC04 steel sheets. The flat strip drawing test simulates friction conditions in the sheet metal-blankholder interface during deep drawing processes. Experimental tests were carried out at various nominal pressures and in dry friction and lubricated conditions. Two widely available gear and engine oils were used in the study. It was found that, in the range of pressures investigated between 3 and 12 MPa, 80W-90 gear oil provided a greater reduction in the value of the coefficient of friction (COF) than 5W-30 engine oil. Gear oil reduced the COF by an average of about 13.4 [%]. The lubrication efficiency depends on the pressure values; the greater the pressure, the lower the lubrication efficiency. A lowering of the value of the main amplitude surface roughness parameters Sa and Sq was generally observed. SEM analysis showed that even under lubrication conditions there was intense flattening of the roughness asperities of the sheet metal.

Analiza uticaja brzine vratila i spoljašnjeg opterećenja na režime podmazivanja radijalnih kugličnih ležajeva

Appropriate lubrication of the rolling bearing is needed to lower the friction between the surfaces in mutual contact and their wear. A lubricant should completely separate the rolling elements from the raceways. The values that affect the efficiency and regimes of lubrication are analyzed in the paper, after which it is introduced a lubrication regime coefficient. This coefficient makes it possible to choose in a simple and fast manner an optimum combination of rolling bearing and lubricant based on the known shaft speed, external load, and rolling bearing operating temperature. For certain bearings with radial contact and certain lubricants, the lubrication regime dependence on the shaft speed and contact load is shown.

Assessment of frictional performance of deep drawing quality steel sheets used in automotive industry

This article presents the results of tribological tests of three grades of deep-drawing quality steel sheets used in the automotive industry. The frictional properties of the sheets were anaysed using a strip drawing test. Friction tests were performed under dry friction and lubrication conditions using machine oil L-AN 46. Additionally, friction tests of pre-strained sheets were also carried out. Cylindrical countersamples with different surface roughness were used. Relationship between the surface roughness, pressure force, lubrication conditions and the value of the friction coefficient were evaluated. It was found that increasing the roughness of the countersamples increased the value of the friction coefficient in both friction conditions analysed. The greater the pressure force, the lower efficiency of lubrication. The effectiveness of reducing the value of the friction coefficient ranged from 20-30% and depended on the pressure force, roughness of the countersamples and the degree of specimen pre-straining.

Research on Lubrication Efficiency Enhancement of High-speed Bearing under Oil-starvation Conditions

Research on Lubrication Efficiency Enhancement of High-speed Bearing under Oil-starvation Conditions

Effect of the Lubrication on the Friction Characteristics of EN AW-2024-T3 Aluminium Alloy Sheets

The article presents the results of friction tests conducted on EN AW-2024 Alclad aluminium alloy sheets. The lubrication efficiency of oleic acid, mineral and vegetable oils with the addition of SiO2 and TiO2 nanoparticles was determined using the strip drawing test to assess the friction conditions in the flange area in the deep drawing process. The samples in the form of sheet metal strips were pulled between countersamples with a rounded surface at a speed of 2.5 mm/s. Gear oil and oleic acid demonstrated the lowest value of the coefficient of friction (COF) in the whole range of nominal pressures investigated. The lowest efficiency in reducing the COF was shown by hydraulic oil, olive oil and machine oil. A high content of TiO2 nanoparticles (0.5-0.9%wt%) is beneficial in the friction process involving oleic acid.

Influence of Contamination of Gear Oils in Relation to Time of Operation on Their Lubricity

The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the second stage, friction tests were conducted for a friction couple “ball-on-disc” in an oil bath at 90 °C on a CSM microtribometer. The quantitative contamination of the gear oils that contained solid particles and the curves representing the friction coefficients of fresh oils with a history of exploitation were compared. The test results were statistically analysed. Exploitation was shown to have a significant impact on the contamination of gear oils. It was revealed that the contamination and the mileage had no effect on the tested oils.

Lubrication efficiency of crankpin bearing using square-cylindrical textures of partial textures optimized by genetic algorithm

Purpose This paper aims to propose an optimal design of the partial textures in the mixed lubrication regime of the crankpin bearing (CB) to maximize the CB's lubrication efficiency. Design/methodology/approach Based on a hybrid model between the slider-crank-mechanism dynamic and CB lubrication, the square-cylindrical textures (SCT) of partial textures designed on the CB’s mixed lubrication regime are researched. The effect of the density distributions of partial textures on CB’s lubrication efficiency is then evaluated via two indices of increasing the oil film pressure (p) and decreasing the frictional force (Ff) of the CB. The SCT’s geometrical dimensions are then optimized by the genetic algorithm to further improve the CB’s lubrication efficiency. Findings The results show that the SCT of partial textures optimized by the genetic algorithm has an obvious effect on enhancing CB’s lubrication efficiency. Especially, with the CB using the optimal SCT of partial textures (4 × 6), the maximum p is significantly increased by 3.7% and 8.2%, concurrently, the maximum Ff is evidently reduced by 9.5% and 21.6% in comparison with the SCT of partial textures (4 × 6) without optimization and the SCT of full textures (12 × 6) designed throughout the CB’s bearing surface, respectively. Originality/value The application of the optimal SCT of partial textures on the bearing surface not only is simple for the design-manufacturing process and maximizes CB’s lubrication efficiency but also can reduce the machining time, save cost and ensure the durability of the bearing compared to use the full textures designed throughout the CB’s bearing surface.

Investigating the efficiency of minimum quantity lubrication and emulsion cooling strategies in end-milling of Inconel 718 using wavy-edge bull-nose helical endmill

This paper investigated the efficiency of applying minimum quantity lubrication (MQL) and emulsion (EM) cooling strategies in end-milling of Inconel 718 using a wavy-edge, bull-nose, helical end-mill (WEBNHE). A mechanistic cutting force model was developed to predict cutting force components and the resultant cutting force of this end-milling process under the cooling strategies. Experiments were conducted to calculated cutting force and edge force coefficients, which incorporated the cooling strategies in the mechanistic model, and to validate the mechanistic model. Cutting force components of both cooling strategies were predicted and compared to each other, and then compared to experimental counterparts. Results showed that predicted cutting force components and the resultant cutting force of both strategies were in good agreement in shape and magnitude with their measured counterparts. Results also showed that end-milling under MQL generated lower cutting force comparing to EM. Moreover, the investigation showed that applying MQL has also improved the productivity and machinability of Inconel 718. Consequently, MQL, meets the demand for cleaner machining of this metal, and serves as an effective and efficient alternative to EM.

Study on Lubrication Efficiency and Friction Power Loss of Engine Based on a Hybrid Hydrodynamic Model

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 loss of engine to a certain extent. Therefore, studies on reducing the friction power loss for the engine and on improving the lubrication efficiency for the engine should be considered coordinately in the dynamic design and optimisation of the engine.