Friction and Wear Reduction by Boundary Film-Forming Viscosity Index Improvers

Günsel, Selda; Smeeth, Matthew; Spikes, H. A.

doi:10.4271/962037

Cited by 41 publications

(26 citation statements)

References 7 publications

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“…This indicates that shear thinning occurred in the contact inlet. The present results agree well with the previous report [17] that the HMw polymers have a greater amount of shear thinning in the contact inlet. Meanwhile, in the low speeds, measurements of oil film thickness for C1mix and HMw-C1mix solutions deviated upward from the theoretical line.…”

Section: Discussionsupporting

confidence: 96%

“…So far, a number of studies on film-forming properties of polymer solutions have been reported [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. It has been well known that under high rolling speeds, in thick film regions, HMw polymer solutions show thinner films than the estimated results from the EHL theory [5][6][7][8][9][10][11][12][13][14][15][16][17]. Bair et al explained that the shear thinning was brought about by shearing a polymer molecule at the contact inlet [21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

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Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Muraki

Nakamura

2009

Proceedings of the Institution of Mechanical Engineers, Part J:

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Oil film thickness of the oils containing non-functionalized polyalkylmethacrylate (PAMA) was determined under pure rolling condition between 0.001 and 1 m/s and a temperature of 40 • C with a glass disc-on-steel roller tester. The measurements for PAMA solutions with shortchain alkyl group (C1mix) showed a pronounced enhancement of film thickness in the low speeds, while those for long chain (C16mix) fell on the theoretical line. Adsorption test indicated that the increase in film thickness for C1mix was due to the absorbed layer formed by polymer molecule. Then, traction behaviour was studied by varying the rolling speed under a slide/roll ratio of 50 per cent with a sapphire disc-on-steel roller tester. In traction-speed curves, the measurements of all the polymer solutions fell on the base oil line in the high speeds. In the region below 0.1 m/s, as the speed was decreased, the traction for high-molecular-weight (HMw) C1mix and C16mix solutions deviated downward from the base oil line. The traction-film parameter curves suggested that the traction for C1mix and HMw-C1mix solutions was influenced by the mutual interaction of polymer molecules in the partial EHL region including thin-film lubrication, where the concentration of the polymer is high compared to bulk solution.

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Section: Discussionsupporting

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Muraki

Nakamura

2009

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Following film failure, various kinds of surfaces may be encountered. A partial list of the possibilities include the following: amorphous reaction products derived from antiwear or EP additives in the oils [29], layers of adsorbed polar polymers [30], adsorbed or trapped layers of nanoparticle additives [31], layers of long alkyl chain organic acids [32], layers of adsorbed hydrocarbons but a few molecules thick [33], friction polymers [34], oxide layers [35], and, of course, metal-to-metal contacts. In the past electrical contact resistance studies have been used to determine the fraction of the load supported by metal-tometal contacts [36].…”

Section: Resultsmentioning

confidence: 99%

Soot Wear in Diesel Engines

Yamaguchi

Untermann

Roby

et al. 2006

Proceedings of the Institution of Mechanical Engineers, Part J:

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In response to regulatory requirements, lubricant manufacturers are seeking oils that minimize soot thickening and the accompanying soot wear. Formulation technology is being developed by additive manufacturers to satisfy these requirements. For example, such work is in progress at Chevron Oronite Company LLC, using the Cummins M-11 exhaust gas recirculation (EGR) engine test as a surrogate for the anticipated soot wear test for PC-10. Simultaneously, the authors developed bench tests to screen candidate formulations and reduce costs. A ball-on-disc sliding wear test, using a PCS Instruments MTM® tribometer, has been investigated. Sliding conditions at high pressure are required for soot polishing wear. Conditions that correlate tribometer test results with M-11 engine results at high soot concentrations (∼9 per cent) have been found. Both ball wear and Stribeck curves were determined in these tests. The high-wear oil progresses from mixed lubrication conditions to boundary lubrication at higher sliding speeds than the low-wear oil. X-ray photoelectron spectroscopy experiments were also conducted on the ball wear scars, revealing differences in the chemical constitution of the tribofilms from the two oils.

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“…New dispersant polymethacrylate viscosity modifiers have appeared [42], which appear to be surface-active VI improvers, and these additives have found use in some engine oil applications.…”

Section: After-treatment Device Compatibilitymentioning

confidence: 99%

Engine Lubricant Trends Since 1990

Taylor

Mainwaring

Mortier

2005

Proceedings of the Institution of Mechanical Engineers, Part J:

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A review is undertaken of the important trends in engine lubricant performance tests that have taken place over the last 10-15 years. Lubricant formulations are driven by industry standard specifications, original equipment manufacturer requirements, and consumer needs. A review is given of the important specifications and associated performance tests, and how these have impacted on lubricant development. The key trends are, firstly, the need for improved fuel economy, secondly, the need for improved oxidation stability, thirdly, the need for improved handling of contaminants (e.g. soot), and, fourthly, the recent move to lubricants containing low levels of sulphur, phosphorus, and sulphated ash, for after-treatment device compatibility reasons.

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Friction and Wear Reduction by Boundary Film-Forming Viscosity Index Improvers

Cited by 41 publications

References 7 publications

Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Soot Wear in Diesel Engines

Engine Lubricant Trends Since 1990

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