Influence of low viscosity on tribological properties for piston ring

Chromium nitride (CrN) is the main protecting coating applied to top rings for gasoline and diesel engines, due to its excellent wear resistance, low friction and minor environmental impacts, especially in modern engines operating with low viscosity oils. Recently, diamond like carbon (DLC) coatings reported improved tribological performance, but at a higher cost. Therefore, in the present work, wear and friction of CrN and DLC coated rings were evaluated on reciprocating and floating liner engine tests running on 0W-20 and 0W-16 lubricant formulations, which additives tailored for different markets (Japanese, European and Emerging). DLC outperformed CrN for both friction and wear when running on lubricant formulations without molybdenum additives. On opposite, with high molybdenum content additives, CrN presented synergic effects that significantly reduced friction and wear, whilst DLC did not. Same comparison on floating liner engine tests demonstrated again superior performance of CrN by 9% reduction on friction losses, running on oils containing molybdenum additives, whilst DLC lowered 6%. From that, it can be estimated 0.4% fuel saving at urban conditions by combining Japanese lubricant oil formulation and CrN top rings.

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An experimental study on tribological properties and air tightness of co-textured cylinder liner-piston ring on an engine tester

Surface Topography Metrology and Properties ◽

10.1088/2051-672x/abda93 ◽

2021 ◽

Vol 9 (1) ◽

pp. 015005

Author(s):

Chenwei Miao ◽

Zhiwei Guo ◽

Chengqing Yuan

Keyword(s):

Experimental Study ◽

Tribological Properties ◽

Piston Ring ◽

Cylinder Liner ◽

Air Tightness

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Tribological properties of h-BN nanoparticles as lubricant additive on cylinder liner and piston ring

Lubrication Science ◽

10.1002/ls.1366 ◽

2016 ◽

Vol 29 (4) ◽

pp. 241-254 ◽

Cited By ~ 37

Author(s):

M. S. Charoo ◽

M. F. Wani

Keyword(s):

Tribological Properties ◽

Piston Ring ◽

Cylinder Liner ◽

Lubricant Additive

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Lipophilic magnetite nanoparticles coated with stearic acid: A potential green and low cost way to improve thermal stability and tribological properties of fully formulated low viscosity engine oils

Tribology International ◽

10.1016/j.triboint.2020.106209 ◽

2020 ◽

Vol 146 ◽

pp. 106209

Author(s):

André Zuin ◽

T. Cousseau ◽

A. Sinatora ◽

H.E. Toma

Keyword(s):

Thermal Stability ◽

Stearic Acid ◽

Tribological Properties ◽

Magnetite Nanoparticles ◽

Low Cost ◽

Engine Oils ◽

Low Viscosity

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Effect of Coating and Low Viscosity Oils on Piston Ring Friction under Mixed Regime of Lubrication through Analytical Modelling

Lubricants ◽

10.3390/lubricants9120124 ◽

2021 ◽

Vol 9 (12) ◽

pp. 124

Author(s):

Anastasios Zavos

Keyword(s):

Coefficient Of Friction ◽

Piston Ring ◽

Roughness Parameter ◽

Contact Conditions ◽

Low Viscosity ◽

Mixed Regime ◽

Uncoated Steel ◽

Coating Morphology ◽

Friction Prediction ◽

The Impact

This paper presents the impact of coating topography in piston ring-liner conjunction under mixed regime of lubrication using low viscosity oils. The study provides a time efficient analytical model including mixed-hydrodynamics regime of lubrication under different contact conditions. The method modified the expressions of the contact load and area of Greenwood-Tripp model in order to capture the real asperities interaction into contact. The model represents the tribological behavior of a thin top ring at Top Dead Centre, where boundary and mixed conditions are predominant. Electroplated CrN and PVD TiN coated rings were studied to predict the ring friction. The results are compared with an uncoated steel ring. The CrN coating shows slighter coefficient of friction, due to the coating morphology and roughness parameters. The TiN coating presents thicker lubricant films and higher coefficient of friction because the surface topography is quite rough with high peaks. This can be explained because of the major contribution of the roughness parameter and asperity slope in the boundary friction prediction.

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Assessment of Tribological Properties of Ti3C2 as a Water-Based Lubricant Additive

Materials ◽

10.3390/ma13235545 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5545

Author(s):

Huong Thi Nguyen ◽

Koo-Hyun Chung

Keyword(s):

Stainless Steel ◽

Tribological Properties ◽

Direct Contact ◽

Friction And Wear ◽

Lubricant Additive ◽

Practical Applications ◽

Normal Forces ◽

Low Viscosity ◽

Water Based ◽

Lubrication Additive

Water-based lubrication has attracted remarkable interest due to its environmental and economic advantages. However, practical applications of water-based lubrication are often limited, mainly because of low viscosity and corrosivity. The use of additives has been proposed to overcome these limitations. In this work, the tribological characteristics of titanium carbide (Ti3C2) MXenes, as additives for water-based lubrication, were systematically investigated for contact sliding between stainless steel under various normal forces and Ti3C2 concentrations. Both friction and wear were found to decrease with increasing Ti3C2 concentration up to 5 wt%, and then increased when the concentration was larger than 5 wt%. The results suggest that Ti3C2 flakes hindered direct contact, particularly at the edges of the contact interfaces. It was further shown that the agglomeration of Ti3C2 flakes may have reduced the hindering when an excessive amount of Ti3C2 (e.g., 7 wt%) was applied. The decreases in the friction coefficient and wear rate with 5 wt% of Ti3C2 concentration w approximately 20% and 48%, respectively. The outcomes of this work may be helpful in gaining a better understanding of the tribological properties of Ti3C2 as a feasible water-based lubrication additive.

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