Current Knowledge on Friction, Lubrication, and Wear of Ethanol-Fuelled Engines—A Review

IF 2.9 3区 工程技术 Q2 ENGINEERING, MECHANICAL
H. Costa, T. Cousseau, Roberto Martins Souza
{"title":"Current Knowledge on Friction, Lubrication, and Wear of Ethanol-Fuelled Engines—A Review","authors":"H. Costa, T. Cousseau, Roberto Martins Souza","doi":"10.3390/lubricants11070292","DOIUrl":null,"url":null,"abstract":"The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tribological challenges to the engine. This review addresses the current state-of-the-art on the effects of ethanol fuel on friction, lubrication, and wear in car engines, and identifies knowledge gaps and trends in lubricants for ethanol-fuelled engines. This review shows that ethanol affects friction and wear in many ways, for example, by reducing lubricant viscosity, which on the one hand can reduce shear losses under full film lubrication, but on the other can increase asperity contact under mixed lubrication. Therefore, ethanol can either reduce or increase engine friction depending on the driving conditions, engine temperature, amount of diluted ethanol in the lubricant, lubricant type, etc. Ethanol increases corrosion and affects tribocorrosion, with significant effects on engine wear. Moreover, ethanol strongly interacts with the lubricant’s additives, affecting friction and wear under boundary lubrication conditions. Regarding the anti-wear additive ZDDP, ethanol leads to thinner tribofilms with modified chemical structure, in particular shorter phosphates and increased amount of iron sulphides and oxides, thereby reducing their anti-wear protection. Tribofilms formed from Mo-DTC friction modifier are affected as well, compromising the formation of low-friction MoS2 tribofilms; however, ethanol is beneficial for the tribological behaviour of organic friction modifiers. Although the oil industry has implemented small changes in oil formulation to ensure the proper operation of ethanol-fuelled engines, there is a lack of research aiming to optimize lubricant formulation to maximize ethanol-fuelled engine performance. The findings of this review should shed light towards improved oil formulation as well as on the selection of materials and surface engineering techniques to mitigate the most pressing problems.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":" ","pages":""},"PeriodicalIF":2.9000,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Lubricants","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.3390/lubricants11070292","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 1

Abstract

The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tribological challenges to the engine. This review addresses the current state-of-the-art on the effects of ethanol fuel on friction, lubrication, and wear in car engines, and identifies knowledge gaps and trends in lubricants for ethanol-fuelled engines. This review shows that ethanol affects friction and wear in many ways, for example, by reducing lubricant viscosity, which on the one hand can reduce shear losses under full film lubrication, but on the other can increase asperity contact under mixed lubrication. Therefore, ethanol can either reduce or increase engine friction depending on the driving conditions, engine temperature, amount of diluted ethanol in the lubricant, lubricant type, etc. Ethanol increases corrosion and affects tribocorrosion, with significant effects on engine wear. Moreover, ethanol strongly interacts with the lubricant’s additives, affecting friction and wear under boundary lubrication conditions. Regarding the anti-wear additive ZDDP, ethanol leads to thinner tribofilms with modified chemical structure, in particular shorter phosphates and increased amount of iron sulphides and oxides, thereby reducing their anti-wear protection. Tribofilms formed from Mo-DTC friction modifier are affected as well, compromising the formation of low-friction MoS2 tribofilms; however, ethanol is beneficial for the tribological behaviour of organic friction modifiers. Although the oil industry has implemented small changes in oil formulation to ensure the proper operation of ethanol-fuelled engines, there is a lack of research aiming to optimize lubricant formulation to maximize ethanol-fuelled engine performance. The findings of this review should shed light towards improved oil formulation as well as on the selection of materials and surface engineering techniques to mitigate the most pressing problems.
当前对乙醇燃料发动机摩擦、润滑和磨损的认识综述
由于全球变暖,迫切需要大幅减少排放,因此需要在交通运输领域进行彻底的能源转型。生物燃料的作用对于弥合当前局势,实现清洁和可持续的未来至关重要。在乘用车中,乙醇燃料的使用减少了气体排放(二氧化碳和其他有害气体),但会给发动机带来摩擦学挑战。这篇综述阐述了乙醇燃料对汽车发动机摩擦、润滑和磨损影响的最新进展,并确定了乙醇燃料发动机润滑剂的知识差距和趋势。这篇综述表明,乙醇在许多方面影响摩擦和磨损,例如,通过降低润滑剂粘度,一方面可以在全膜润滑下减少剪切损失,但另一方面可以增加混合润滑下的粗糙面接触。因此,乙醇可以减少或增加发动机摩擦,具体取决于驾驶条件、发动机温度、润滑剂中稀释乙醇的量、润滑剂类型等。乙醇会增加腐蚀并影响摩擦腐蚀,对发动机磨损有显著影响。此外,乙醇与润滑剂的添加剂强烈相互作用,在边界润滑条件下影响摩擦和磨损。关于抗磨添加剂ZDDP,乙醇导致具有改性化学结构的摩擦膜变薄,特别是磷酸盐更短,硫化铁和氧化物的量增加,从而降低了它们的抗磨保护作用。由Mo-DTC摩擦改进剂形成的摩擦膜也受到影响,影响了低摩擦MoS2摩擦膜的形成;然而,乙醇有利于有机摩擦改进剂的摩擦学性能。尽管石油行业对润滑油配方进行了微小的更改,以确保乙醇燃料发动机的正常运行,但缺乏旨在优化润滑油配方以最大限度地提高乙醇燃料发动机性能的研究。这篇综述的结果应该有助于改进石油配方,以及选择材料和表面工程技术来缓解最紧迫的问题。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Lubricants
Lubricants Engineering-Mechanical Engineering
CiteScore
3.60
自引率
25.70%
发文量
293
审稿时长
11 weeks
期刊介绍: This journal is dedicated to the field of Tribology and closely related disciplines. This includes the fundamentals of the following topics: -Lubrication, comprising hydrostatics, hydrodynamics, elastohydrodynamics, mixed and boundary regimes of lubrication -Friction, comprising viscous shear, Newtonian and non-Newtonian traction, boundary friction -Wear, including adhesion, abrasion, tribo-corrosion, scuffing and scoring -Cavitation and erosion -Sub-surface stressing, fatigue spalling, pitting, micro-pitting -Contact Mechanics: elasticity, elasto-plasticity, adhesion, viscoelasticity, poroelasticity, coatings and solid lubricants, layered bonded and unbonded solids -Surface Science: topography, tribo-film formation, lubricant–surface combination, surface texturing, micro-hydrodynamics, micro-elastohydrodynamics -Rheology: Newtonian, non-Newtonian fluids, dilatants, pseudo-plastics, thixotropy, shear thinning -Physical chemistry of lubricants, boundary active species, adsorption, bonding
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:604180095
Book学术官方微信