The feasibility of using electrostatic monitoring to identify diesel lubricant additives and soot contamination interactions by factorial analysis

Booth, James; Nelson, Kenneth; Harvey, Terry J.; Wood, R.J.K.; Wang, L.; Powrie, H.E.G.; Martinez, Josephine

doi:10.1016/j.triboint.2006.04.004

Cited by 49 publications

(34 citation statements)

References 18 publications

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“…Beshouri refers to soot "completely disabling" ZDDP [38]. Recently Booth et al have also suggested a similar corrosion-abrasion mechanism to that outlined above and identified iron sulphide as the species most likely to be controlling this process [28]. However other work has found that ZDDP plays a strong role in reducing wear of sooted oils and that secondary ZDDP is more effective at this than primary ZDDP.…”

Section: Discussionmentioning

confidence: 94%

Antagonistic Interaction of Antiwear Additives and Carbon Black

2009

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SUMMARYIt is well known that the presence of soot in engine oils can lead to an increase in wear of engine parts. This is a growing problem as soot levels in diesel engine oils are rising due to a combination of extended drain intervals and the various methods employed to reduce NOx formation such as retarded ignition and exhaust gas recirculation.Several different mechanisms have been proposed by which soot might lead to an increase in wear in mixed lubrication conditions, of which the most widely favoured is abrasion by soot, either of the rubbing metallic parts in engines or of the antiwear additive films formed on rubbing metal surfaces.In this study it is shown that the combination of mixed alkyl ZDDP and carbon black (used as soot surrogate) is strongly antagonistic in terms of wear. In a lubricant containing carbon black, the presence of ZDDP leads to considerably more wear than if ZDDP is left out. A similar, though less severe antagonism is also seen with primary ZDDP and other antiwear and EP additives. By varying the lubricant film thickness it is shown that the effect of carbon black in ZDDP-containing oils is to promote wear up to quite thick hydrodynamic film conditions, approaching the secondary carbon black particle size.It is proposed that the antagonistic wear effect results from a corrosion-abrasive mechanism in which the reaction film formed by antiwear additive and rubbing metal surface is very rapidly and continually abraded by carbon black. At most carbon black concentrations, wear rate then becomes controlled by the rate of initial antiwear additive film formation, which for secondary ZDDP is very rapid, rather than by the kinetics of the abrasive process.From this understanding, strategies for reducing the impact of engine soot on wear can be deduced.

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Section: Discussionmentioning

confidence: 94%

Antagonistic Interaction of Antiwear Additives and Carbon Black

2009

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“…It has been seen in other studies by George et al 40 that the ratio of ZDDP to dispersant is related to the level of wear when soot is present. Other studies [41][42][43][44] including Kulp et al, Booth et al have indicated that it is possible to get antagonistic effects from the combination of ZDDP and dispersants. This effect is due to either a complex formation in the bulk liquid or competition with the metal surface active sites.…”

Section: Discussionmentioning

confidence: 99%

Soot–additive interactions in engine oils

O׳Neill

Simko

et al. 2009

Lubrication Science

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Soot is known to cause engine wear. In this work, we focus on how engine oil formulation affects sootrelated wear, and how the lubricant-derived anti-wear fi lm changes when soot is present. Friction and wear experiments of fully and partially formulated diesel engine oils (containing basestock, dispersants and viscosity modifi ers) are conducted with a ball-on-disk rig in the presence of carbon black (CB) as a soot surrogate. The friction coeffi cient was largely unaffected by CB dispersed in the oils, but electrically insulating fi lm formation, an indication of the formation of anti-wear fi lms, was decreased. Wear on the disk was found to either remain the same or decrease when CB was present, depending on the oil formulation. An examination of the lubricant-derived fi lms using Raman and Auger electron spectroscopies found that the presence of more abundant amorphous carbon and lesser amounts of anti-wear fi lm components on the surface was associated with higher wear.

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“…Electrostatic sensing is especially sensitive to the tribo-charge generated from wear debris [16], contact potential difference (CPD) [17,18] and chemical interactions within the lubricant [19]. The CPD effect arises from subtle differences in surface work functions especially when surface phase transformation or tribo-film formation or stripping occurs.…”

Section: Introductionmentioning

confidence: 99%

The influence of contact conditions on surface reaction layers formed between steel surfaces lubricated by an aviation oil

Wang

Wood

2007

Tribology International

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This study focuses on the influence of load and temperature on the formation and stability of tribo-films for bearing steel on bearing steel contacts lubricated with an aviation oil, EXXON Turbo 2380 (TCP based -tricresyl phosphate) at ambient temperatures. Experiments were carried out on a pin-on-disc (POD) tribometer (with a ball-on-flat geometry) under an average loading rate of 0.17 N s À1 and sliding speed of 3 m s À1. The X-ray photoelectron spectroscopy (XPS) analysis on the worn surfaces of ball and disc shows that a tribo-film forms on both surfaces at room temperature. The formation and removal of the tribo-film are faster on the ball due to the nature of contact between the ball and disc. It was found that the tribo-films formed at room temperature are vulnerable to initial disc temperature. The higher the initial temperature the higher the load carrying capacity. The tribo-film growth and contact deterioration have been monitored by acoustic emission (AE) and electrostatic charge (ESP) sensing systems in real time. The results show that both AE and ESP can detect the tribo-film and contact breakdown and have great potential for on-line condition monitoring of lubricated tribo-contacts. r

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The feasibility of using electrostatic monitoring to identify diesel lubricant additives and soot contamination interactions by factorial analysis

Cited by 49 publications

References 18 publications

Antagonistic Interaction of Antiwear Additives and Carbon Black

Antagonistic Interaction of Antiwear Additives and Carbon Black

Soot–additive interactions in engine oils

The influence of contact conditions on surface reaction layers formed between steel surfaces lubricated by an aviation oil

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