Friction in Automotive Engines

Allmaier, Hannes; Priestner, Christoph; Sander, David Emanuel; Reich, Franz Markus

doi:10.5772/51568

Cited by 30 publications

(28 citation statements)

References 25 publications

(30 reference statements)

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“…Previous works 3,9,10,11 investigated monograde lubricants that do not show a strong nonNewtonian behaviour. In the work of Sander et al 8 and in this work the investigated lubricant is a multigrade lubricant that exhibits a distinct nonNewtonian behaviour.…”

Section: Lubricant Rheology and Simulationmentioning

confidence: 99%

“…From these results 3 a very simple equivalent bearing temperature relation was derived for the isothermal EHD simulation that is consequently able to predict the journal bearing friction losses very accurately for a large range of different lubricants, journal speeds and loads as was shown in direct comparison to experimental data (see in particular Allmaier et al 9 and Sander et al 8 ). A complete and exhaustive discussion of these points is given in Allmaier et al 10 (the cited book chapter Friction in automotive engines can be downloaded for free at http://www.intech.com).…”

Section: Lubricant Rheology and Simulationmentioning

confidence: 99%

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Non-Newtonian and running-in wear effects in journal bearings operating under mixed lubrication

Allmaier

Sander

Priebsch

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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For the study of mixed lubrication in dynamically loaded journal bearings, this paper employs a combined experimental and simulative approach. Extensive measurements on a journal bearing test rig with a low-viscosity 0W20 multi-grade lubricant with a strong Non-Newtonian behaviour provide the basis for the investigation of the lubrication conditions in journal bearings. In this paper, temperature effects and the influence of running-in (breaking-in) wear are investigated. To this task, a high dynamic load is applied to the journal bearing under test. To vary the lubrication conditions, only the journal speed is changed. To investigate the lubrication conditions a detailed and validated simulation approach is utilized that takes into account both the piezoviscous effect and the non-Newtonian behaviour of the investigated lubricant as well is able to describe metal-metal contact. With this combined approach the run-in process of the journal bearing under test can be investigated as well as the role of temperature settling effects.

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Section: Lubricant Rheology and Simulationmentioning

confidence: 99%

Section: Lubricant Rheology and Simulationmentioning

confidence: 99%

Non-Newtonian and running-in wear effects in journal bearings operating under mixed lubrication

Allmaier

Sander

Priebsch

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

View full text Add to dashboard Cite

show abstract

“…It is made available specifically for use in combustion engines and features a very high viscosity index (VI) without the necessity to add VI-improving additives. VI-improvers can cause a significant non-Newtonian behaviour [21][22][23][24] of the lubricant. Therefore, a lubricant without these is expected to maintain its high viscosity also in the presence of locally high shear rates, which is an advantage for highly loaded contacts.…”

Section: The Tested Lubricantsmentioning

confidence: 99%

Friction Reduction Tested for a Downsized Diesel Engine with Low-Viscosity Lubricants Including a Novel Polyalkylene Glycol

et al. 2017

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Abstract:With the increasing pressure to reduce emissions, friction reduction is always an up-to-date topic in the automotive industry. Among the various possibilities to reduce mechanical friction, the usage of a low-viscosity lubricant in the engine is one of the most effective and most economic options. Therefore, lubricants of continuously lower viscosity are being developed and offered on the market that promise to reduce engine friction while avoiding deleterious mixed lubrication and wear. In this work, a 1.6 L downsized Diesel engine is used on a highly accurate engine friction test-rig to determine the potential for friction reduction using low viscosity lubricants under realistic operating conditions including high engine loads. In particular, two hydrocarbon-based lubricants, 0W30 and 0W20, are investigated as well as a novel experimental lubricant, which is based on a polyalkylene glycol base stock. Total engine friction is measured for all three lubricants, which show a general 5% advantage for the 0W20 in comparison to the 0W30 lubricant. The polyalkylene glycol-based lubricant, however, shows strongly reduced friction losses, which are about 25% smaller than for the 0W20 lubricant. As the 0W20 and the polyalkylene glycol-based lubricant have the same HTHS-viscosity , the findings contradict the common understanding that the HTHS-viscosity is the dominant driver related to the friction losses.

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“…The method was put to test in direct comparison to experimental data in two different works [4,6] for different speeds, loads and lubricant classes. For a rather complete overview we refer to [5] (The book chapter can be downloaded for free at http://www.intechopen.com/).…”

Section: Determining the Friction Loss Of The Journal Bearingsmentioning

confidence: 99%

“…However, the accuracy of these methods is not clear as there has not been an attempt to the knowledge of the authors to directly compare simulation and experiment systematically for a large range of different speeds, dynamic loads and lubricant classes. Only recently a simulation method was published [4][5][6] which was shown to be able to calculate the friction power losses of journal bearings under realistic working conditions with very high dynamic loads highly accurately.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Journal Bearing Friction Losses in a Heavy-Duty Diesel Engine

et al. 2015

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Internal combustion engines (ICE) for the use in heavy-duty trucks and buses have to fulfil demanding requirements for both vehicle efficiency as well as for emission of greenhouse gases. Beside the piston assembly the journal bearings are among the largest contributors to friction in the ICE. Through a combination of measurements and validated simulation methods the journal bearing friction losses of a state-of-the-art heavy-duty Diesel engine are investigated for a large range of real world operating conditions. To this task recently developed and extensively validated simulation methods are used together with realistic lubricant models that consider the Non-Newtonian behaviour as well as the piezoviscous effect. In addition, the potential for further friction reduction with the use of ultra-low viscosity lubricants is explored. The results reveal a potential of about 8% friction reduction in the journal bearings using a 0W20 ultra-low viscosity oil with an HTHS-viscosity (The HTHS-viscosity is defined as the dynamic viscosity of the lubricant measured at 150• C and at a shear rate of 10 6 s −1 ) of 3.6 mPa s. For the investigated engine, HTHS-viscosity limitations are determined which indicate that the use of lubricants with further reduced HTHS-viscosity would require engine and/or journal bearing modifications to be able to maintain the high service life of the engine.

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Friction in Automotive Engines

Cited by 30 publications

References 25 publications

Non-Newtonian and running-in wear effects in journal bearings operating under mixed lubrication

Non-Newtonian and running-in wear effects in journal bearings operating under mixed lubrication

Friction Reduction Tested for a Downsized Diesel Engine with Low-Viscosity Lubricants Including a Novel Polyalkylene Glycol

Analysis of the Journal Bearing Friction Losses in a Heavy-Duty Diesel Engine

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