Understanding Soot Mediated Oil Thickening Through Designed Experimentation - Part 2: GM 6.5L

Bardasz, Ewa A.; Carrick, Virginia; Ebeling, V. L.; George, Herman F.; Graf, Michelle; Kornbrekke, Ralph E.; Pocinki, Sara B.

doi:10.4271/961915

Cited by 36 publications

(7 citation statements)

References 14 publications

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“…Sato et al 45 showed that oil viscosity, fi lm thickness and soot diameter affected wear in his studies with oils containing soot ranging from 0.1 to 9.8 wt %. George et al, 40 Bardasz et al 46 and Aldajah et al 47 showed that wear was not proportional to soot content.…”

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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Section: Discussionmentioning

confidence: 99%

Soot–additive interactions in engine oils

O׳Neill

Simko

et al. 2009

Lubrication Science

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“…Recent regulatory mandates, such as API CJ4, to reduce nitrogen oxides (NO x ) and other particulate matters (PMs) imposed by the United States Environmental Protection Agency (U.S. EPA) have resulted in the use of exhaust gas recirculation (EGR) in an internal combustion engine. − Currently, EGR is the most effective technique available for reducing NO x emissions in a heavy-duty diesel engine. Use of EGR partially replaces the excess oxygen as well as lowers the combustion chamber temperature, thus reducing the formation of NO x ; NO x primarily forms when a mixture of oxygen and nitrogen is subjected to high temperatures. − At the same time, the application of EGR also results in higher soot loading in diesel engines because the deficiency of oxygen for the reaction with carbon in the time scale characteristic of the combustion process results in incomplete combustion of the fuel. − Higher soot loading in engines causes a deleterious effect on engine component wear, functionality of lubricant oil, and particulate emissions. − …”

Section: Introductionmentioning

confidence: 99%

Influence of Engine Age on Morphology and Chemistry of Diesel Soot Extracted from Crankcase Oil

et al. 2016

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In this study, the role of engine age on the structure and chemistry of crankcase soot was studied using X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. Results indicate that the basic structure of the carbonaceous species remains the same in all cases and is composed of turbostratic carbon. However, there are some very subtle changes in the structure of the soot as the age of the engine increases. Older engines have a greater proportion of non-crystalline amorphous carbonaceous constituents in the soot relative to newer engines. In addition, the wear-induced debris increase with the age of the engine, with a larger proportion of phosphates of Ca and Zn as well as sulfates of Ca in the soot of older engines. The presence of these wear debris particles incorporated in the soot extracted from the crankcase indicates that they arise from three-body abrasive wear between the soot and the tribofilms formed within the engine.

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“…Mainwaring [16] concluded that the primary particle size was the most fundamental in determining wear and that this was because the primary particles were entrained into the contact (provided they were dimensionally smaller than the film thickness). However Bardasz et al concluded that soot aggregates were responsible for abrasion [13]. Jao [26] showed that soot particles were sufficiently hard to abrade metal diesel engine parts.…”

Section: Introductionmentioning

confidence: 99%

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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Understanding Soot Mediated Oil Thickening Through Designed Experimentation - Part 2: GM 6.5L

Cited by 36 publications

References 14 publications

Soot–additive interactions in engine oils

Soot–additive interactions in engine oils

Influence of Engine Age on Morphology and Chemistry of Diesel Soot Extracted from Crankcase Oil

Antagonistic Interaction of Antiwear Additives and Carbon Black

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