Investigation of PVD Piston Ring Coatings With Different Lubricant Formulations

2017 ◽  
Author(s):  
Eduardo Tomanik ◽  
Hiroshi Fujita ◽  
Shinya Sato ◽  
Eliel Paes ◽  
Ciro Galvao ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Piston Ring ◽  
Superior Performance ◽  
Low Friction ◽  
Dlc Coatings ◽  
Low Viscosity ◽  
Lubricant Oil ◽  
Wear And Friction ◽  
Oil Formulation ◽  
Urban Conditions

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.

Friction and Wear Behavior Evaluation of DLC Films Grown in Multilayer of Carbon and Silicon

2014 ◽  
Vol 802 ◽  
pp. 392-397
Author(s):  
Patrícia Cristiane Santana da Silva ◽  
Gislene Valdete Martins ◽  
Evaldo José Corat ◽  
Vladimir Jesus Trava-Airoldi
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Wear Behavior ◽  
High Hardness ◽  
Low Friction ◽  
Dlc Coatings ◽  
Hard Materials ◽  
Dc Discharge ◽  
Pulsed Dc ◽  
Pulsed Dc Discharge

Excellent tribological properties of hard materials surface are desirable in several sectors of industry. Diamond-like carbon (DLC) coatings are well known for their low friction, excellent wear resistance, and high hardness. In this work, DLC films were deposited on AISI M2 steel using a modified PECVD pulsed-DC discharge. Multilayer of carbon and silicon were grown, alternately. Samples were produced with different layer thickness for carbon and silicon, and the same parameters for each material layer, in order to investigate friction coefficient in each layer, evaluate rate deposition variation and the gradient behavior of different layers. Raman spectroscopy was used to verify the structural arrangement of carbon atoms. The films were also characterized by scanning electron microscopy and EDX. Tribological tests were performed to observe adhesion between layers and substrate, friction, and wear. The results showed the variation of friction coefficient and that deposition rate declines when increasing number of layers.

Regulation on tribological performance of tungsten-doped DLC coatings by Choline Chloride-Urea and -Thiourea Deep Eutectic Solvents

2022 ◽  
Author(s):  
Fan Yang ◽  
Yuting Li ◽  
Zhaofan Yue ◽  
Qingbo Fan ◽  
Hao Li ◽  
...  
Keyword(s):  
Surface Properties ◽  
Friction And Wear ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Tribological Performance ◽  
Lubrication System ◽  
Low Friction ◽  
Dlc Coatings ◽  
Solid Liquid ◽  
Tribochemical Interaction

Abstract Solid-liquid composite lubrication system has attracted an increased interest for low friction and wear. Nevertheless, the effect of mechanical and surface properties of the solid materials, especially the mechanical and surface properties governed by doping elements, on the tribological performance solid-liquid composite lubrication system is still not well comprehended. Here, we reported the effect of W content on the mechanical and surface properties of W-DLC coatings as well as the tribological properties of W-DLC coatings under (choline chloride-urea and choline chloride-thiourea) deep eutectic solvents lubrication. Although the wear of W-DLC coatings under dry friction increases with W content, the wear under DESs is slight when coatings show excellent wettability to DESs or a DES-derived tribochemical film is formed. We demonstrate that the tribological behavior of W-DLC and DESs composite lubrication system is related to the mechanical properties of W-DLC coatings together with the contact angle and tribochemical interaction between DESs and W-DLC coatings.

Anti-Wear and Friction-Reducing Characteristics of Two Kinds of Ceramic Additives

2010 ◽  
Vol 139-141 ◽  
pp. 274-279
Author(s):  
Yu Zhou Gao ◽  
Jiang Tao Wang ◽  
Shi Yong Liu ◽  
Hui Chen Zhang
Keyword(s):  
Thin Film ◽  
Friction Coefficient ◽  
Chemical Analysis ◽  
Direct Contact ◽  
Friction And Wear ◽  
Low Friction ◽  
Initial Stage ◽  
Thin Carbon ◽  
Wear And Friction ◽  
Worn Surface

Two kinds of ceramic additives have been developed that one is the serpentine particles and another is a blend of serpentine particles and catalyst. The tribological properties of the addition of different additives are investigated through a series of friction and wear experiments. Wear surface and the composition of the tribofilm were examined by SEM, EDS and XPS. In case of single serpentine additive, tribo-film can be formed gradually on the worn metal surface. The friction coefficient is about 0.11. The tribofilm mainly consists of Mg and Si elements transferred from the additive. This can compensates part of wear mass loss, avoids the direct contact of the two rubbing surfaces, and thus effectively improves the anti-wear characteristics. In case of the blend oil additive, the tribo-film formed obviously on the worn surface in the initial stage and no obvious film at end of the test. However, the friction coefficient can lower even to 0.007~0.008 compared with the above experiment. The worn surface becomes very smooth. Chemical analysis shows that there is a very thin film of carbon concentration with thickness of 30~50nm on the worn surface. Existence of the very thin carbon-concentrated film and mirror-like surface generates super low friction coefficient.

Medium ion energy synthesis of hard elastic fullerene-like hydrogenated carbon film with ultra-low friction and wear in humid air

2015 ◽  
Vol 143 ◽  
pp. 188-190 ◽  
Author(s):  
Yongfu Wang ◽  
Junmeng Guo ◽  
Jun Zhao ◽  
Delei Ding ◽  
Yongyong He ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Carbon Film ◽  
Low Friction ◽  
Humid Air ◽  
Ion Energy ◽  
Energy Synthesis

Friction Reduction via Piston and Ring Design for an Advanced Natural-Gas Reciprocating Engine

2004 ◽  
Author(s):  
Grant Smedley ◽  
S. H. Mansouri ◽  
Tian Tian ◽  
Victor W. Wong
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Substantial Reduction ◽  
Friction Reduction ◽  
Design Parameters ◽  
Design Strategies ◽  
Low Friction ◽  
Piston Skirt ◽  
Model Predictions

Friction from the power cylinder represents a significant contribution to the total mechanical losses in internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel consumption, and reduced emissions. In this study, models incorporating piston ring dynamics and piston secondary motion with elastic skirt deformation were applied to a Waukesha natural gas power generation engine to identify the main contributors to friction within the piston and ring pack system. Based on model predictions, specific areas for friction reduction were targeted and low-friction design strategies were devised. The most significant contributors to friction were identified as the top ring, the oil control ring, and the piston skirt. Model predictions indicated that the top ring friction could be reduced by implementing a skewed barrel profile design or an upward piston groove tilt design, and oil control ring friction could be reduced by decreasing ring tension. Piston design parameters such as skirt profile, piston-to-liner clearance, and piston surface characteristics were found to have significant potential for the reduction of piston skirt friction. Designs were also developed to mitigate any adverse effects that were predicted to occur as a result of implementation of the low-friction design strategies. Specifically, an increase in wear was predicted to occur with the upward piston groove tilt design, which was eliminated by the introduction of a positive static twist on the top ring. The increase in oil consumption resulting form the reduction in the oil control ring tension was mitigated by the introduction of a negative static twist on the second ring. Overall, the low-friction design strategies were predicted to have potential to reduce piston ring friction by 35% and piston friction by up to 50%. This would translate to an improvement in brake thermal efficiency of up to 2%, which would result in a significant improvement in fuel economy and a substantial reduction in emissions over the life of the engine.

scholarly journals Development of Highly Hydrogenated DLC Coatings for Solid Lubricant Applications in Space

2005 ◽  
Author(s):  
A. Vanhulsel ◽  
R. Jacobs ◽  
K. Van Acker ◽  
E. Roberts ◽  
F. Velasco ◽  
...  
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Applied Load ◽  
Solid Lubricant ◽  
Solid Lubricants ◽  
Ambient Atmosphere ◽  
Test Environment ◽  
Load Range ◽  
Dlc Coatings ◽  
Aisi 52100 Steel

The development of advanced solid lubricants is of considerable importance to space tribology. The most common solid lubricant coatings today are based on MoS2, lead or PTFE. However, none of these coatings can simultaneously fulfill all specifications, with regard to friction and wear, under ambient atmosphere and in vacuum. Consequently research is currently being aimed at further improvements in advanced solid lubricant coatings. One approach is to optimize Diamond Like Carbon (DLC) coatings to meet the specifications. In this study, the feasibility of highly hydrogenated DLC coatings (∼ 50 at% hydrogen) for solid lubricant applications is assessed. The coatings were deposited on AISI 52100 steel substrates and tested in ball-on-disc tribometers in air, vacuum and dry nitrogen environments. It was found that the test environment has the most decisive effect on both friction and wear rate, while these parameters are only slightly affected by varying the applied load under a given atmosphere. It was concluded that highly hydrogenated DLC coatings are capable of yielding ultra-low friction values in vacuum (μ = 0.008). The average friction coefficient range obtained in humid air, dry nitrogen and vacuum for the range of applied loads were respectively 0.22 to 0.27, 0.02 to 0.03, and 0.007 to 0.013. Coating lifetime was over 100 000 cycles for the entire load range tested in air and nitrogen, but was affected by the applied load as far as tests in vacuum are considered. The specific wear rate was lower than 1×10–5 mm3 N-1 m-1 under all test conditions, which was considered favourable.

Lubricant Flow Optimization of Large Two Stroke Marine Diesel Engine Piston Ring Packs

2016 ◽  
Author(s):  
Matthias Stark ◽  
Richard Mittler
Keyword(s):  
Piston Ring ◽  
Superior Performance ◽  
Exhaust Gas ◽  
Oil Consumption ◽  
Major Step ◽  
Oil Transportation ◽  
Lubrication Performance ◽  
Marine Diesel ◽  
Piston Ring Pack ◽  
Ring Pack

Approaching a characterization of different contributors to the lube oil balance of an engine becomes important when aiming at enhancing lubrication performance and reducing its contribution to exhaust gas emissions. It is essential to quantify relevant data helping to determine lubrication losses related to particular tribosystem components. Recent activities focused on rating distinct tribosystem component effects on their contribution to total lube oil consumption and the possibility to most effectively modify those. This paper thus describes the most effective tribosystem component modifications, consisting of the application of a substantially modified piston ring pack and the introduction of lube oil accumulating grooves in order to considerably enhance lubrication performance. A proper prediction of piston ring pack dynamics and tribodynamic effects on the lube oil film is essential to design a superior piston ring pack in terms of an optimized piston running behaviour and lube oil transportation. One major step designing such a ring pack is based on the consequent application of a novel 3D piston ring pack simulation tool to enhance lube oil transportation characteristics and distribution. Lube oil accumulating grooves are introduced to reduce lubrication losses due to so called ring pack spray. The ring pack spray is a result of accumulated lubricant in the pressurized piston ring pack expanding into the scavenge air receiver during the scavenging phase. Mentioned effect was analysed in detail in order to determine the amount of related lubricant losses. Investigations in this context lead to the application of lube oil accumulating grooves and hence can be considered an important design aspect to reduce total lube oil consumption. Tribosystem performance validation was performed on the basis of the application of an SO2 tracing technology on a full scale engine test in order to determine relevant tribosystem component modifications in real time. The sulphur content of fuel and lube oil considerably influences the formation of particulate matter in the exhaust gas, following chemical reactions of sulphur oxidation. Hence detecting SO2 in the exhaust gas is a direct measure to determine the amount of lubricant in the exhaust gas composition. Finally this report demonstrates measurement results describing the superior performance of the modified tribosystem.

Effects of polymers concentration on EHL film-forming in point contacts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liangwei Qiu ◽  
Xiaoyang Chen ◽  
Fakai Dong
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Point Contact ◽  
High Concentration ◽  
Content Type ◽  
Base Oils ◽  
Low Viscosity ◽  
Lubricant Oil ◽  
Pure Rolling ◽  
Film Forming

Purpose This paper aims to experimentally investigate the film-forming capability of base oils containing poly-methacrylate (PMA) and poly-isobutene (PIB), in a point contact under pure rolling. Design/methodology/approach By using the relative light intensity method, the film thickness is calculated from the interferometer images which are captured by multiple-contact optical elastohydrodynamic lubricated test rig. Findings The test results reveal that polymers, both PMA and PIB, have a significant contribution to the film-forming capability of base oils and the film thickness increases with concentration. The forming-film capabilities for PMA and PIB in base oils are similar at low concentration, while PIB gives a higher film thickness than PMA at high concentration. Shear-thinning phenomenon are observed in all polymer-based oils. Originality/value The polymer usually as an additive is added into the low viscosity base oils to improve the properties of lubricant oil. This paper reports the lubricated properties of PMA and PIB with different concentrations in base oils and to evaluate their functional mechanism in a point contact. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0263/

scholarly journals The Effect of Surface Texturing on Dry Gross Fretting

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 92 ◽  
Author(s):  
Agnieszka Lenart ◽  
Pawel Pawlus ◽  
Slawomir Wos ◽  
Andrzej Dzierwa
Keyword(s):  
Friction And Wear ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Disc Surface ◽  
Abrasive Jet Machining ◽  
Wear And Friction ◽  
Steel Disc ◽  
Disc Configuration ◽  
Effect Of Surface ◽  
Ball On Disc

The effect of steel disc surface texturing on dry gross fretting in a ball-on-disc configuration was studied. Dimples were created with abrasive jet machining. The tribological performance of sliding pairs, steel–steel and steel–ceramics, was experimentally studied. The character of surface texturing effect was related to the dominant wear type. During steel–steel contact, the presence of dimples on disc surfaces could lead to increases in wear and friction. However, the escape of wear debris into dimples could result in reductions of friction and wear in the steel–ceramics configuration.

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