The role of soot particles in the tribological behavior of engine lubricating oils

Hu, Enzhu; Hu, Xianguo; Liu, Tianxia; Fang, Ling; Dearn, Karl D.; Xu, Hongming

doi:10.1016/j.wear.2013.05.002

Cited by 96 publications

(60 citation statements)

References 29 publications

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“…A small percentage of the soot produced in the cylinders becomes entrained within the engine lubricant oil, either via blow‐by gases passing the piston rings (Green & Lewis, ) or via a thermophoretic mechanism into the oil film on the cylinder walls (Kittelson et al ., ; Suhre & Foster, ). The soot‐oil relationship is extremely complex and as such reports in the literature on the effect of soot on lubricant oil viscosity, friction and on engine wear at times appear contradictory (Heywood, ; Chinas‐Castillo & Spikes, ; Green et al ., ; Green & Lewis, ; Antusch et al ., ; Hu et al ., ; Salehi et al ., ). The particular changes that take place depends not only on the concentration of soot, but also on its morphology (Chinas‐Castillo & Spikes, ; Antusch et al ., ).…”

Section: Introductionmentioning

confidence: 97%

“…Additionally, the oil formulation, contact type and lubrication regime will all play a role in the changes observed. Depending on the particular combination of contact‐type and the lubricant oil chosen in a study, the presence of soot has been observed to cause both increases and decreases in friction and oil viscosity (Hu et al ., ; Salehi et al ., ) and rates of wear within engines (Salehi et al ., ).…”

Section: Introductionmentioning

confidence: 97%

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Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Haffner-Staton

Rocca

Fay

2018

Journal of Microscopy

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The aim of this work is to make progress towards the development of 3D reconstruction as a legitimate alternative to traditional 2D characterization of soot. Time constraints are the greatest opposition to its implementation, as currently reconstruction of a single soot particle takes around 5-6 h to complete. As such, the accuracy and detail gains are currently insufficient to challenge 2D characterization of a representative sample (e.g. 200 particles). This work is a consideration of the optimization of the steps included within the computational reconstruction and manual segmentation of soot particles. Our optimal process reduced the time required by over 70% in comparison to a typical procedure, whilst producing models with no appreciable decrease in quality.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Haffner-Staton

Rocca

Fay

2018

Journal of Microscopy

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“…A research group at Argonne National Laboratory recently revealed conversion of diamond nanoparticles (sp 3 ) to carbon nano‐onions triggered by sulfur compounds (MoS 2 ) under solid lubrication . Despite most studies reporting adverse effects of soot in engine lubrication, some literature conversely suggested improved tribological properties when CB was introduced to a fully formulated (CD AE 15W‐40) oil …”

Section: Introductionmentioning

confidence: 99%

“…[11] Despite most studies reporting adverse effects of soot in engine lubrication, some literature conversely suggested improved tribological properties when CB was introduced to a fully formulated (CD AE 15W-40) oil. [12] Are soot and ZDDP interactions antagonistic, and how do these two compounds together prompt the wear process? Most of the above literature work focused on one or two material pairs while changing the material mechanical properties or experimental parameters such as load and soot concentration.…”

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confidence: 99%

Material‐Dependent Antagonistic Effects between Soot and ZDDP

Kumara

Meyer

2020

Adv Materials Inter

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While soot in engine oil is known to accelerate the wear of diesel and gasoline direct‐injection compression‐ignition engines, there is a lack of consensus on the wear mechanism though various hypotheses have been proposed in the literature. Particularly, some recently observed antagonistic effects between soot and a common lubricant antiwear additive, zinc dialkyldithiophosphate (ZDDP), while others did not. The discrepancy is, in part, explained by the strong alloy dependence of such antagonism discovered in this study. Four alloys, 52100 steel and M2, M50, and A2 tool steels, are tested in lubricants containing carbon black (CB, a soot surrogate) with and without ZDDP present. Adding the CB alone to the oil increases the wear rate for all steel alloys as expected. However, distinct wear performance is observed for the four steel alloys when ZDDP is introduced to the CB‐containing oil: while the 52100 steel has notable wear reduction, the three tool steels suffer significant wear increase. Comprehensive tribofilm characterization suggests that the Mo content in the steel alloy and the sulfur from ZDDP strongly influence wear behavior. The combination of CB/Mo‐catalyzed sulfidation and CB‐accelerated abrasion is hypothesized to be responsible for the high wear of the Mo‐alloyed tool steels.

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“…Rabaso et al claimed that mixing inorganic fullerene nanoparticles (IF‐MoS 2 ) did not affect the lubricating behaviors of a commercial oil significantly due to the presence of dispersants . The presence of carbonaceous materials, e.g., carbon soot, at the sliding interface exerts a remarkable influence on the resulting friction and wear. Zhou et al proposed that diamond‐like carbon can provide a catalytic effect enhancing ZDDP tribofilm formation, in which the tribochemical reactions between the ZDDP additive and the steel surface are accelerated by carbon species …”

Section: Introductionmentioning

confidence: 99%

Unusual Competitive and Synergistic Effects of Graphite Nanoplates in Engine Oil on the Tribofilm Formation

Pham

Wan

Tieu

et al. 2019

Adv Materials Inter

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To exploit the improved efficiency from formulated oil modified with graphite nanoplates (GNP), it is important to understand how GNP behave alongside conventional additives such as zinc dialkyl dithiophosphates (ZDDP). The results in this work demonstrate unusual tribological responses of engine oil due to GNP additions, which cannot be explained by the traditionally low shearing mechanism between graphene layers in GNP. A competitive and synergistic effect of GNP on tribofilm formation is proposed for this unusual friction and wear behavior. The presence of GNP modifies the tribofilm formation and spontaneously creates alternate hard and soft regions from the microscopic view of the surface. At low concentrations (≤0.05 wt%), graphene is formed by shear‐assisted exfoliation of GNP and intermixed with intermediate oxide region. Due to its random orientation, graphene produces mechanical reinforcement of the tribofilm, but low shear yielding is not achieved. This gives rise to high friction but low wear conditions. At higher concentrations (>0.05 wt%), GNP align with their hexagonal sheets parallel to the surface to promote low‐shear sliding, but wear increases. This is due to GNP clumping together which makes them less effective at forming graphene and providing stable reinforcement of the tribofilm.

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The role of soot particles in the tribological behavior of engine lubricating oils

Cited by 96 publications

References 29 publications

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Material‐Dependent Antagonistic Effects between Soot and ZDDP

Unusual Competitive and Synergistic Effects of Graphite Nanoplates in Engine Oil on the Tribofilm Formation

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