Preventing Catastrophic Camshaft Lobe Failures in Low Emission Diesel Engines

Geehan, J. A. Mc; Ryason, P. R.

doi:10.4271/2000-01-2949

Cited by 11 publications

(3 citation statements)

References 21 publications

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“…Soot is abrasive not only to metal and metal oxide surfaces but also to protective films. Decreasing soot agglomerate size (by, for example, dispersing the soot with suitable dispersants or dispersant VI improvers) is a well recognized method of decreasing soot-related wear in non-EGR engines [39]. These results suggest that this technique will also be helpful in EGR engines.…”

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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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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“…These are mildly accelerated conditions compared with typical valve-train entrainment velocities and contact pressures. Hertzian contact stresses in the range 1.7-2.1 GPa have been reported for low-emission diesel engines [31]. Entrainment velocities have been reported as high as 7 m/s for a 2.0 l four-cylinder GM Ricardo Hydra Gasoline engine [32] and 4.8 m/s for a Sequence VE engine tappet system (ASTM D 5302) [33].…”

Section: Test Conditions and Proceduresmentioning

confidence: 99%

The effects of diesel contaminants on tribological performance on sliding steel on steel contacts

Ramkumar

Harvey

Wood

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part J:

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This article presents the findings from a parametric study examining the effect of four contaminants (soot, oxidation, moisture, and sulphuric acid) at varying levels (four for each). It was observed that all contaminants and contaminant levels reduce the conductivity of the oil. Oxidation and soot contaminants produced large increases in viscosity. The wear rate was mainly influenced by acid and soot additions, while the coefficient of friction was increased by all contaminants and contaminant levels. The steady-state charge levels changed for some contaminants. The best correlation of steady-state charge with the other measured tribological parameters of wear rate, friction, and temperature is seen for the series of oxidized oils. The multi-contaminated oil (L4 Â 4) shows remarkably little degradation in tribological performance.Analysis of the wear mechanisms shows that soot and oxidation produced abrasion and polishing wear, respectively, while sulphuric acid and moisture produced corrosive wear.

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“…Contact stresses in the range 1.7-2.07 GPa have been reported for lowemission diesel engines. 19 Entrainment velocities have been reported as high as 7 m/s for a 2.0 l four-cylinder GM Ricardo Hydra Gasoline engine 20 and 4.8 m/s for a Sequence VE engine tappet system. 21…”

Section: Test Conditionsmentioning

confidence: 99%

Factorial study of diesel engine oil contamination effects on steel and ceramic sliding contacts

Ramkumar

Harvey

Wood

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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The present work investigates the effects of diesel contaminants and their interaction on tribological properties for bearing steel (En31) and ceramic (Si 3 N 4) sliding contacts using a factorial study. The contaminants are soot, sulphuric acid, moisture and oxidation, and each contaminant has three different level of concentration (low, medium and high) in the test matrix. The factorial test matrix consisted of 20 tests, constructed from a quarter fractional factorial test matrix with four points at the medium values for the contaminants. Results from this matrix required six further tests to elucidate aliased pairs of interactions using Bayesian model selection. A pin-on-disc tribometer was used to carry out all the experiments. All tests were carried out under ambient conditions at 5 m/s sliding speed and contact stress of 1.5-2.05 GPa to simulate a valve-train in a diesel engine with fully formulated heavy-duty diesel engine oil used as lubricant. Four different tribological properties were studied. The factorial study showed that charge was influenced by tribocouple material; the silicon nitride discs produced higher charge than steel discs. However, it was opposite for friction; the silicon nitride disc gave lower friction and the pins showed higher friction than their steel counterparts. For wear scar and temperature, soot contaminant was found to be important. The two important interactions were found for the charge response, with the interaction between sulphuric acid and pin material being more important than sulphuric acidoxidation interaction. Similarly to charge, an interaction between sulphuric acid and pin material interaction was found for friction.

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Preventing Catastrophic Camshaft Lobe Failures in Low Emission Diesel Engines

Cited by 11 publications

References 21 publications

Soot Wear in Diesel Engines

Soot Wear in Diesel Engines

The effects of diesel contaminants on tribological performance on sliding steel on steel contacts

Factorial study of diesel engine oil contamination effects on steel and ceramic sliding contacts

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