The mechanism of layer formation and the function of additives used in fully formulated engine crankcase oils

Kaleli̇, Hakan; Berthier, Yves

doi:10.1016/s0167-8922(02)80021-9

Cited by 10 publications

(9 citation statements)

References 5 publications

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“…Some additives are multifunctional and carry out more than one role. For example, zinc dialkyl dithiophosphate is acting as a combined anti‐wear, anti‐oxidant and corrosion inhibitor additive, sulphonate dispersants are acting to neutralize acids, prevent varnish formation as well as preventing the agglomeration of particles and deposition of carbon in engines, organo‐molybdenum friction modifier compounds also behave as anti‐wear and anti‐oxidant additives (Kaleli and Berthier, 2001; Product Review, 1997).…”

Section: Introductionmentioning

confidence: 99%

Analysis of effects of oil additive into friction coefficient variations on journal bearing using artificial neural network

Durak

Salman

Kurbanoğlu

2008

Industrial Lubrication and Tribology

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PurposeThe purpose of this paper is to investigate the effect of a lubricant with a polytetrafluoroethylene (PTFE)‐based additive on the friction behaviour in a steadily loaded journal bearing using an experimental and artificial neural network approach.Design/methodology/approachThe collected experimental data, such as pressure variations, are employed as training and testing data for artificial neural networks (ANNs). A feed forward back propagation algorithm is used to update the weight of the network during the training.FindingsAn artificial neural network predictor has superior performance for modelling journal bearing systems under different lubricant conditions.Research limitations/implicationsA feed forward back propagation algorithm is used as a training algorithm for the proposed neural networks. Various training algorithms can be used to train the proposed network. Various lubricants and concentration ratio of the different additives can be investigated.Practical implicationsThe simulation results suggest that the artificial neural predictor would be used as a predictor for possible experimental applications, especially different lubrication conditions on the modelling journal bearing system.Originality/valueThe paper discusses a new modelling scheme known as ANNs. A neural network predictor has been employed to analyze the effects of a lubricant with a PTFE‐based additive on the friction behaviour in a steadily loaded journal bearing under different operating conditions.

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Section: Introductionmentioning

confidence: 99%

Analysis of effects of oil additive into friction coefficient variations on journal bearing using artificial neural network

Durak

Salman

Kurbanoğlu

2008

Industrial Lubrication and Tribology

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“…This sulphur probably originated from the mineral base oil and possibly influences the wear behaviour at elevated temperatures significantly. Elementary sulphur itself can provide wear protection (Stratmann et al , 2017; Kaleli, 2002). Following the Arrhenius equation, the reaction of sulphur is increased with increasing temperature, starting at local temperatures of 100°C (Stratmann et al , 2017; Kaleli, 2002; Taylor, 2014), which might be achieved locally at 80°C test temperature in the wear track.…”

Section: Resultsmentioning

confidence: 99%

“…Elementary sulphur itself can provide wear protection (Stratmann et al , 2017; Kaleli, 2002). Following the Arrhenius equation, the reaction of sulphur is increased with increasing temperature, starting at local temperatures of 100°C (Stratmann et al , 2017; Kaleli, 2002; Taylor, 2014), which might be achieved locally at 80°C test temperature in the wear track. This is a possible explanation for the comparably good wear protection of both greases without ZDDP.…”

Section: Resultsmentioning

confidence: 99%

“…With increasing temperature, the patches become larger and progress towards a continuous tribofilm (Spikes, 2004; Brizmer et al , 2017). Glassy phosphates are part of a characteristic ZDDP-based tribofilm, which mainly consists of Zn, P, S, Ca and O (Gosvami et al , 2015; Kaleli, 2002; Stratmann et al , 2017; Hsu et al , 2020). The general structure is well-described in literature (Gosvami et al , 2015; Brizmer et al , 2017; Spikes, 2004; Gellman and Spencer, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Influence of temperature on wear performance of greases in rolling bearings

Rosenkranz

Richter

Jacobs

et al. 2021

ILT

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Purpose Rolling bearing operation under mixed and boundary lubrication conditions may lead to heavy adhesive or abrasive wear, which may lead to wear-induced rolling bearing failure. The purpose of this paper is to investigate the wear protection capabilities of different grease compositions at varying temperatures. It is considered that the temperature influences the lubrication conditions, the behaviour of grease components, namely, bleed oil and thickener, as well as the tribofilm formation due to tribo-chemical interactions between additives and surfaces. Design/methodology/approach In this study, four different greases were produced on the basis of a mineral base oil by varying the thickener and the addition of ZDDP. Various grease-lubricated rolling bearing experiments were conducted in a wide temperature range from 0°C to 120°C. Subsequently, the wear pattern, tribofilm formation and grease structures were analysed. Thereby, the influence of the different grease thickeners and the performance of ZDDP as a common antiwear and extreme pressure additive was evaluated. Findings The results show a strong temperature-dependency and allow a classification of temperature ranges concerning wear protection. At low temperatures, all greases provide a very good wear protection without the evidence of additive-based tribofilm formation. In the experiments at elevated temperatures, ZDDP tribofilms were formed. The formation depends on the thickener type: in comparison to lithium thickener, polyurea thickener favours more protective tribofilms at the same temperature. The experimental results show that medium temperatures in the range of 40°C–60°C are critical concerning wear due to the insufficient tribolayer formation and limited load carrying capacity of the grease. Originality/value Temperature is a key operating parameter for grease lubrication in roller bearings. The experimental work enables consideration of different impact pathways of temperature by combining roller bearing tests and microanalysis.

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“…Some additives are multifunctional and carry out more than one role. For example, zinc dialkyl dithiophosphate is acting as a combined anti-wear, anti-oxidant and corrosion inhibitor additive, sulphonate dispersants are acting to neutralize acids, prevent varnish formation as well as preventing the agglomeration of particles and deposition of carbon in engines, organo-molybdenum friction modifier compounds also behave as antiwear and antioxidant additives (Kaleli and Berthier, 2001;Industrial Lubrication and Tribology, 1997).…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the effect of additive on the tribological properties journal bearing under running‐in and start‐up or shut‐down stages

Durak

Adatepe²,

Bıyıklıoğlu³

2008

Industrial Lubrication and Tribology

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Purpose -The purpose of this paper is to study the effects of additive on the tribological properties such as friction coefficient and wear loss in the journal bearings during start-up (or shut-down) and running-in periods. Design/methodology/approach -In this study, fully formulated commercial engine mineral oil (SAE 20W50) and commercial oil additives (3 per cent) added into this oil were tested to determine the tribological performances such as friction coefficient, wear loss and the effect of the additive on protective layers formed on the sliding bearing's surfaces. Findings -This study presents an experimental procedure for obtaining practical results pertaining to the tribological performance of the journal bearing under running-in and start-up or shut down stages. Also, in this study, the authors have attempted to show the linkage between the oil additive and the running conditions such as running-in and start-up and shut-down in effecting performance of the journal bearing. It is well known that one of the roles of an additive is to form a protective layer to reduce friction coefficient in lubricated contacts. Originality/value -The paper is of value in presenting an experimental procedure for obtaining practical results pertaining to the tribological performance of the journal bearing under running-in and start-up or shut down stages.

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The mechanism of layer formation and the function of additives used in fully formulated engine crankcase oils

Cited by 10 publications

References 5 publications

Analysis of effects of oil additive into friction coefficient variations on journal bearing using artificial neural network

Analysis of effects of oil additive into friction coefficient variations on journal bearing using artificial neural network

Influence of temperature on wear performance of greases in rolling bearings

Experimental study of the effect of additive on the tribological properties journal bearing under running‐in and start‐up or shut‐down stages

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