Gasoline-Engine Camshaft Wear: The Culprit is Blow-By

McGeehan, J. A.; Yamaguchi, E. S.

doi:10.4271/892112

Cited by 29 publications

(6 citation statements)

References 12 publications

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“…These combustion products are strong pro-oxidants and in addition to their role in viscosity increase and sludge formation [62], they have a marked influence on rates of wear, especially of the valve train [62,63]. Introduction of NO x at a rate of 0.008 m 3 s −1 at 2000 ppm into the crankcase of a 2-l Nissan OHC engine during a motored test increased cam nose wear by 1.6 times over the same test with no NO x .…”

Section: Oxy Acids Of Nitrogen and No Xmentioning

confidence: 99%

Friction, Wear and the Role of Additives in Controlling Them

Bovington

2009

Chemistry and Technology of Lubricants

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The laws of friction are described. Abrasive, adhesive, contact fatigue and corrosive wear mechanisms are explained. The tribological regime of boundary lubrication is discussed in the context of the Stribeck curve and surface film formation. Physical processes for surface film formation and their properties are examined for oxygen-, nitrogen-, sulphur-, phosphorus, boron, molybdenum-containing organic compounds and ZDDP in particular. ZDDP film formation is discussed in depth and the influence of dispersants described. Interactions between reduced ZDDP levels and molybdenum compounds to maintain wear protection and antioxidancy are considered for the requirements of lower SAPS formulations in future formulations.

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Section: Oxy Acids Of Nitrogen and No Xmentioning

confidence: 99%

Friction, Wear and the Role of Additives in Controlling Them

Bovington

2009

Chemistry and Technology of Lubricants

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“…Standard free energy changes are G • r (300 K) = −39.83 kJ/mol and G • r (500 K) = −50.57 kJ/mol (Pankratz,et al (15)). Since FeS was not found at 32 • C, it appears that reaction [1] occurred very slowly at this low temperature. Moreover, the fact that FeS 2 was not found on the wear track at 100 • C suggests that reaction [1] occurred in the high-temperature sliding tests.…”

Section: Base Oil With Metal Deactivator Additivementioning

confidence: 89%

“…Since FeS was not found at 32 • C, it appears that reaction [1] occurred very slowly at this low temperature. Moreover, the fact that FeS 2 was not found on the wear track at 100 • C suggests that reaction [1] occurred in the high-temperature sliding tests. The absence of the S2 2p peak at 100 • C suggests that either FeS 2 was not produced or was rapidly converted during sliding, resulting in the formation of FeS (reaction [1]).…”

Section: Base Oil With Metal Deactivator Additivementioning

confidence: 89%

X-Ray Photoelectron Spectroscopy Analysis of Antiwear Tribofilms Produced on Boundary-Lubricated Steel Surfaces from Sulfur- and Phosphorus-Containing Additives and Metal Deactivator Additive

Komvopoulos

Yamaguchi

et al. 2004

Tribology Transactions

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X-ray photoelectron spectroscopy (XPS) was performed on AISI 52100 steel surfaces subjected to sliding in the boundary lubrication regime at 32 and 100 • C. The specimens were lubricated with base oil blended with individual additives containing sulfur (S), phosphorus (P), or metal deactivator, as well as base oil with all the previous additives in the same amounts as in the single blends. XPS spectra were analyzed to confirm the formation and determine the chemical composition of the antiwear tribofilms produced on the steel surfaces during sliding. The use of S-and P-containing additives on the tested disk surfaces revealed that tribochemical reactions resulted in the formation of antiwear tribofilms containing S-and P-rich components. Results for the multi-additive blend provided evidence for two components in the produced tribofilm, appearing to consist primarily of sulfide and phosphate. This investigation provides new insight into the competing roles of these compounds on the tribological properties of the antiwear tribofilms. The significance of the sulfide components is demonstrated by the more pronounced antiwear effect of the S-containing additive in the multi-additive formulation.

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“…As the soot concentration increases beyond a certain level, the dispersants are unable to suspend it, resulting in the formation of large soot agglomerates ($1 lm) which leads to loss of lubricity and abrasive surface wear. Requirements for reduced diesel vehicle nitrogen oxide emissions are leading to changes in engines, such as retarding the engine timing and exhaust gas recirculation that increase the amount of generated soot even further [3]. For the experimental system, carbon black (CB) was chosen as a simplified substitute for soot.…”

Section: Introductionmentioning

confidence: 99%

“…For the experimental system, carbon black (CB) was chosen as a simplified substitute for soot. Soot mostly consists of aggregated spheroid particles, primarily of aggregated carbon combined into an extended aromatic network [2][3][4][5][6][7]. Characteristics of soot can vary, including the degree of crystallinity, the size of the primary particles, the number of aggregated particles, and the amount and type of functional groups on the surface of the particle [2,6,7].…”

Section: Introductionmentioning

confidence: 99%