EHL/mixed transition of fully formulated environmentally acceptable gear oils

Bayat, Reza; Lehtovaara, Arto

doi:10.1016/j.triboint.2020.106158

Cited by 14 publications

(9 citation statements)

References 48 publications

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“…The results show that of M2 was approximately 15 % higher than EAL2. On the other hand, from [31] it is observed that the pressure-viscosity coefficient of EALs is smaller. Therefore, the friction reduction by EALs is mainly attributed to two rheological parameters: the lower pressure-viscosity coefficient of EALs, and their lower limiting shear stress at which shear-thinning becomes…”

Section: Resultsmentioning

confidence: 97%

Friction and temperature mapping of environmentally acceptable gear oils

Bayat¹,

Lehtovaara²

2020

Finnish J. Trib.

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In recent years, environmental issues have raised the demand to protect the environment against the pollution caused by the uncontrolled spillage of lubricating oils. One solution is using Environmentally Acceptable Lubricants (EALs), however, these oils are more expensive than the common mineral oils. The consumers require to test the oil performance using test machines but testing in real machines is costly and time-consuming. Small test machines like ball-on-disc have been previously used for friction mapping and ranking gear oils. In this paper, the friction maps are measured from 0.65 GPa to 1.25 GPa, and temperature maps are devised to experimentally simulate the gear contact along the line of action. Results illustrate that EALs can provide up to 60 % better frictional efficiency that leads to 20 oC cooler oil temperature in high-pressure contacts operating under elastohydrodynamic lubrication (EHL) regime.

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Section: Resultsmentioning

confidence: 97%

Friction and temperature mapping of environmentally acceptable gear oils

Bayat¹,

Lehtovaara²

2020

Finnish J. Trib.

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“…The results showed that the ball-on-disc test can rank the oils' frictional properties as FZG test did [11]. Regarding the gear application, the ball-on-disc test rig has been widely used also for empirical simulation of the polymer gears [12], friction of the gear oils in different lubrication conditions [13][14][15][16][17], micro pitting [18], and scuffing [19][20][21]. Tribofilm plays an important role in failure prevention in gear contact, however, to this time, there has not been any paper investigating the tribofilm variation at the gear line of action.…”

Section: Introductionmentioning

confidence: 97%

Tribofilm Formation of Simulated Gear Contact Along the Line of Action

Bayat

Lehtovaara

2021

Tribol Lett

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In this paper, an experimental simulation method was used for evaluating the tribofilm formation in rolling/sliding contact at different points in the line of action. A ball-on-disc test method was employed by which the pressure and slide to roll ratio of gear contact could be simulated. In order to reach a general conclusion, four different oils and two surface roughness were involved in the experiments. The tribofilm evolution was captured using spacer layer interferometry method, and the correlation of tribofilm with the location at the line of action was studied. Results showed that there is a threshold pressure for the tribofilm formation around which the tribofilm growth rate is maximum. Above this threshold pressure, the tribofilm formation is not stable, and the wear is dominant. Below this threshold pressure, the tribofilm growth rate rises by increasing the pressure and the gear contact is safely protected by a stable tribofilm. Graphic Abstract

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“…Reduced wear and friction can be achieved using lubricants. Low speed or heavy load can result in a lack of lubricating oil film formation, leading to severe wear on the contact surface when mechanical assemblies start up, gear pairs mesh, or the direction of the engine piston changes [4][5][6][7]. MoS2, WS2, and other nanomaterials have been developed to strengthen the lubricant film [8,9].…”

Section: Introductionmentioning

confidence: 99%

Tribological Performance and Rheological Properties of Engine Oil with Graphene Nano-Additives

et al. 2022

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Nanoparticles dispersed in lubricants are being studied for their ability to reduce friction and wear. This paper examines SAE 5W-30 oil enhanced with dispersed graphene nanoplates for tribological and rheological properties. Graphene nanoplate (GNs) concentration effects on the rheological and tribological properties of 5W-30 base oil (0.03, 0.06, 0.09, 0.12, and 0.15 wt percent) were tested. Under various loads, a four-ball testing model was used to conduct a tribological analysis (200, 400, 600, and 800 N). Kinematic viscosity is calculated, and base oil and nanofluid-added 5W30 lubricant are compared for thermal conductivity and flashpoint. Wear scar and coefficient of friction improved by 15% and 33% with nano-additives. When related to the base oil, the flashpoint, thermal conductivity, kinematic viscosity, and pour point all increased, by 25.4%, 77.4%, 29.9%, and 35.4%, respectively. The addition of GNs improved the properties of 5W30 engine oil.

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EHL/mixed transition of fully formulated environmentally acceptable gear oils

Cited by 14 publications

References 48 publications

Friction and temperature mapping of environmentally acceptable gear oils

Friction and temperature mapping of environmentally acceptable gear oils

Tribofilm Formation of Simulated Gear Contact Along the Line of Action

Tribological Performance and Rheological Properties of Engine Oil with Graphene Nano-Additives

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