A Study of Lubricant Condition in the Piston Ring Zone of Single-Cylinder Diesel Engines Under Typical Operating Conditions

Saville, S.B.; Gainey, F.D.; Cupples, Shirin; Fox, Miles; Pickers, D. J.

doi:10.4271/881586

Cited by 28 publications

(8 citation statements)

References 11 publications

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“…• formation of the acid catalyst (RO) 2 [92] and field tests [93]. This disulphide has a kind of 'depot' function for the acid catalyst (RO) 2 PSSH such that just sufficient acid is always present.…”

Section: Antioxidant Technology For Passenger Car Engine Oilsmentioning

confidence: 99%

Oxidative Degradation and Stabilisation of Mineral Oil-Based Lubricants

Aguilar

Mazzamaro

Rasberger

2009

Chemistry and Technology of Lubricants

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Thermally induced hydrocarbon oxidation is a self-accelerating autoxidation process and is divided into 'low'-, 30-120 • C, and 'high'-, >120 • C, temperature phases. The first has four stages -induction of radical chain reactions, propagation, branching and then termination. Mechanisms of these processes are described and discussed. Differences in hydrocarbon reactivity are related to molecular structure. For hydrocarbon oxidation >120 • C, the first stage is the same as low-temperature oxidation but with reduced selectivity and increased reactivity; second, the oxidation phase becomes diffusion controlled as hydrocarbon viscosities increase from progressive polycondensation of higher molecular weight products, causing varnish and sludge formation. Base oil oxidation stabilities depend upon their derivation, whether solvent neutral, hydrocracked or synthetic, and their response to antioxidant treatment. Lubricant oxidation control focuses on radical scavengers and hydroperoxide decomposers and their synergistic mixtures.Engine oils increasingly use phenolic and aminic antioxidants as radical scavengers with organometallic complex antioxidants. Sterically hindered phenols substituted at 2-and 6-positions by t-butyl groups are particularly effective, reacting successively with peroxy radicals to form stable cyclohexadieneone peroxides. Secondary amines as either two aryl or phenyl and naphthyl groups are very effective at eliminating four peroxy radicals per molecule. They are more effective by a ratio of 4:2 than the sterically hindered phenols below 120 • C. At higher temperatures a catalytic cycle is suggested as an extended stabilisation mechanism. Transition metal ions with two valence states, Fe 2+/3+ , Cu 1+/2+ , etc. as trace quantities of metal soaps catalyse/retard autoxidation according to concentration and/or combination of metals. They catalyse or inhibit oxidation by complexing and decomposing hydroperoxides or can also oxidise peroxy radicals and reduce alkyl radicals to inert products. Organomolybdenum complexes such as molybdenum dialkyldithiocarbamates, MDTC, are increasingly used to stabilise engine lubricants particularly because of synergy with other antioxidants such as alkylated diphenylamines. 107 R.M. Mortier et al. (eds.), Chemistry and Technology of Lubricants, 3rd edn.,

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Section: Antioxidant Technology For Passenger Car Engine Oilsmentioning

confidence: 99%

Oxidative Degradation and Stabilisation of Mineral Oil-Based Lubricants

Aguilar

Mazzamaro

Rasberger

2009

Chemistry and Technology of Lubricants

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“…The oil-control ring controls the flow by scraping excess lubricant back into the crankcase. Feedback between the crankcase and the ring-pack oil occurs on a timescale of a few minutes [11,12], which depends on the particular engine and ring-pack design. The operating conditions in the crankcase and ringpack are quite different.…”

Section: Oil Transport and Changes In Oil Propertiesmentioning

confidence: 99%

Bridging macroscopic lubricant transport and surface tribochemical investigations in reciprocating engines

Wong

Thomas

Watson

2007

Proceedings of the Institution of Mechanical Engineers, Part J:

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Engine design studies are often conducted with one of two distinct focuses on two different scales: overall engine analysis or localized surface analysis. However, recent engine research requires a more combined approach. Classical tribological experiments and models have been developed usually for general contacting surfaces under specific operating conditions. They attempt to simulate the actual engine environment, which varies significantly with component design and engine operating conditions. Macroscopic engine studies, on the other hand, yield information pertaining to the overall engine system, such as component dynamics, lubricant flow, pressures, and temperatures. These macroscopic operating parameters serve as boundary conditions to the localized surface or tribochemical problem. This paper discusses the macroscopic oil transport processes in the engine and presents several current engine performance problems, such as in friction reduction, modelling wear with antiwear tribofilms, and minimizing deposit formation and emission of ash-related species. It also illustrates applications of the combined analysis of bulk oil transport in the engine with material surface phenomena and tribochemistry. A specific example involves the oil supply to the piston ring-pack and changes in oil and additive characteristics in that region.

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“…TRZ sampling has previously been undertaken by a number of research establishments with heavy duty diesel and gasoline engines [4,8,9]; these have all been of older design than the Hydra engine. This method of extracting oil from the rear of a piston ring during engine operation is based on the theory that when the top ring is sitting on the lower flank the pressure differential between the entrance to the sample hole and the atmosphere forces some of the combustion gases, along with oil from around the sample hole down the pipe in the form of a mist.…”

Section: Trz Sampling Systemmentioning

confidence: 99%

Extraction and tribological investigation of top piston ring zone oil from a gasoline engine

Lee

Priest

Stark

et al. 2006

Proceedings of the Institution of Mechanical Engineers, Part J:

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eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract: With tightening emission regulations, increased expected fuel economy, and longer drain intervals impacting on lubricant formulation, greater understanding of how oil degrades in an automotive engine is becoming ever more important. Equally significant is the effect that this degraded lubricant has on the tribological operation of the engine, particularly its overall internal friction and component wear. In a previous paper, four tests to degrade oil in a single cylinder engine were reported (Lee, P. M. et al. The degradation of lubricants in gasoline engines: development of a test procedure to evaluate engine oil degradation and its consequences for rheology. In 31st Leeds-Lyon Symposium). These tests were set up such that the lubricating oil was degraded in the ring pack before returning to the sump, where it was sampled and chemical and rheological analysis undertaken. This paper reports the extension of this work using the same Hydra engine and describes how oil has additionally been extracted from the rear of the top piston ring during engine operation. This extracted oil has then been subjected to similar analysis as the sump oil samples in the previous tests, along with additional analysis to look at the tribological properties of the oil using tribometers.The results clearly show significant differences in the rheological, tribological, and chemical properties of the fresh oil and used sump oil samples when compared with the top ring zone (TRZ) oil samples, particularly the effect of load on the levels of volatiles present in the TRZ samples and their effect on traction and friction coefficient values during tribological testing.

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A Study of Lubricant Condition in the Piston Ring Zone of Single-Cylinder Diesel Engines Under Typical Operating Conditions

Cited by 28 publications

References 11 publications

Oxidative Degradation and Stabilisation of Mineral Oil-Based Lubricants

Oxidative Degradation and Stabilisation of Mineral Oil-Based Lubricants

Bridging macroscopic lubricant transport and surface tribochemical investigations in reciprocating engines

Extraction and tribological investigation of top piston ring zone oil from a gasoline engine

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