Refinement of Engine in-cycle losses of Parasitic and Errant Dynamic Nature (Encyclopaedic)

寄生和错误动态性质的发动机循环损失的细化（百科全书）

• 批准号: EP/G012334/1
• 负责人: Homayoon Rahnejat
• 金额: $ 149.48万
• 依托单位: Loughborough University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG012334%2F1
• 关键词: Refinement; Engine; cycle; losses; Parasitic

The automotive industry in the UK remains one of the key strategic sectors in the overall national R&D footprint, employing some 160,000 people (38000 in motor sport) [1]. The UK is home to a number of global OEMs representing the largest inward investment in the country's R&D through the establishment of significant technical centres. Influenced by the stringent emission mandates (Euro 4: Directive 98/70/EC and amendment: 70/220/EEC) and noise pollution targets (EU:DIRECTIVE 70/157/EEC and amendment: 2007/34/EC, USA: FHWA-HEP-06-020) improvements in engine efficiency have assumed a high priority with automotive manufacturers. An effective way is to reduce frictional (parasitic) and mechanical (errant dynamic) losses, accounting for 15 / 25 % of lost energy. Errant dynamic losses refer to inertial imbalance and structural deformation, also contributing to noise and vibration pollution. The largest mechanical losses are due to translational imbalance of pistons and rotational imbalance of the crank system, with increasing engine roughness due to demands for high output power-to-weight ratio. Engine roughness refers to structural vibration of lightly damped engine systems. Worst conditions for frictional losses arise under stop-start conditions or other transient events, where interactions between system dynamics and tribological behaviour of engine sub-systems play significant roles (Andersson [2]). Nearly half of the friction losses in internal combustion engines originate in the piston-ring-cylinder contacts, about 50% (Blau et al [3]), two thirds of which is attributable to the compression ring. Hitherto, interactions between frictional and mechanical losses have not received the fundamental analysis that they deserve. With increasing demand for high performance engines, the piston is subjected to even higher loads and, thus, increased losses. At the same time, engine development is driven by high fuel efficiency and output power-to-weight ratio, as well as reduced NOx and particulate emissions. These requirements frequently lead to conflicting demands put on combustion, system dynamics and tribological performance. It is significant to note that a mere 4% reduction in parasitic losses can lead to 1% improvement in fuel efficiency. Rapidly diminishing fossil fuel deposits in the UK's territorial waters and the difficulty of extraction, together with the adverse environmental impact of significant vehicular emissions, make improved fuel efficiency by reduction of parasitic losses a national imperative and a paramount objective. Whilst large national projects have been undertaken for development of efficient combustion strategies, a large consortium project has not hitherto been undertaken for tribology and dynamics of the piston-connecting rod-crankshaft sub-system which contributes significantly to engine losses. This project will bring together experts in the fields of dynamics, surface engineering, contact mechanics, lubricant rheology and tribology to collectively provide unique and novel solutions for this challenging multi-disciplinary problem of utmost importance to the UK automotive industry. An approach incorporating these inter-related disciplines within a unified analysis framework is referred to as multi-physics. This points to a single integrated project across all the interacting disciplines to deal with physics on a wide range of scales from large displacement dynamics to small thermo-elastic distortion of components and further down to micro-scale tribological contacts (such as EHD films, and asperity interactions) and onto the diminishing conjunctions of surface textured patterns with nano-scale interactions such as the molecular behaviour of lubricants due to their physical chemistry and free surface energy effects.

英国的汽车工业仍然是整个国家研发足迹的关键战略部门之一，雇用了大约160，000人（38，000人从事赛车运动）[1]。英国是许多全球原始设备制造商的所在地，通过建立重要的技术中心，代表了该国研发领域最大的外来投资。受严格的排放要求（Euro 4：Directive 98/70/EC和修正案：70/220/EEC）和噪声污染目标（EU：Directive 70/157/EEC和修正案：2007/34/EC，USA：FHWA-HEP-06-020）的影响，发动机效率的提高已经成为汽车制造商的高度优先事项。一种有效的方法是减少摩擦（寄生）和机械（错误的动态）损失，占损失能量的15 /25%。不正常的动态损失是指惯性不平衡和结构变形，也会导致噪音和振动污染。最大的机械损失是由于活塞的平移不平衡和曲柄系统的旋转不平衡，以及由于高输出功率重量比的需求而增加的发动机粗糙度。发动机粗糙度是指轻度阻尼发动机系统的结构振动。摩擦损失的最坏条件出现在停止-启动条件或其他瞬态事件下，其中系统动力学和发动机子系统的摩擦学行为之间的相互作用起着重要作用（Andersson [2]）。内燃机中几乎一半的摩擦损失源自活塞-环-气缸接触，约50%（Blau等人[3]），其中三分之二可归因于压缩环。然而，摩擦损失和机械损失之间的相互作用还没有得到应有的基本分析。随着对高性能发动机的需求增加，活塞承受甚至更高的载荷，因此损失增加。与此同时，发动机的发展受到高燃油效率和输出功率重量比以及减少NOx和颗粒排放的驱动。这些要求经常导致对燃烧、系统动力学和摩擦学性能的相互矛盾的要求。值得注意的是，寄生损失仅减少4%就可以导致燃料效率提高1%。英国领土沃茨中的化石燃料储量迅速减少，开采困难，加上大量车辆排放对环境的不利影响，使得通过减少寄生损失来提高燃料效率成为国家的当务之急和首要目标。虽然大型的国家项目已经进行了有效的燃烧策略的发展，一个大的财团项目迄今尚未进行的摩擦学和动力学的活塞连杆曲轴子系统，这大大有助于发动机的损失。该项目将汇集动力学，表面工程，接触力学，润滑剂流变学和摩擦学领域的专家，共同为英国汽车行业最重要的挑战性多学科问题提供独特和新颖的解决方案。将这些相互关联的学科纳入统一的分析框架的方法被称为多物理。这指向一个单一的综合项目，跨越所有相互作用的学科，以处理从大位移动力学到组件的小热弹性变形，再到微尺度摩擦学接触的广泛尺度上的物理学（例如EHD薄膜，和粗糙的相互作用），并到表面纹理图案与纳米-规模相互作用，如润滑剂的分子行为，由于其物理化学和自由表面能的影响。

项目成果

Performance of Poly Alpha Olefin Nanolubricant

• DOI: 10.3390/lubricants8020017
• 发表时间: 2020-02-01
• 期刊: LUBRICANTS
• 影响因子: 3.5
• 作者: Dolatabadi, Nader;Rahmani, Ramin;Brunton, Charles
• 通讯作者: Brunton, Charles

Atomic Scale Friction in the Function of Modified Eyring Activation Energies

原子尺度摩擦与修正艾林活化能的函数关系

• DOI: 10.4028/www.scientific.net/kem.642.3
• 发表时间: 2015
• 期刊: Key Engineering Materials
• 作者: Chong W

On the Transient Three-Dimensional Tribodynamics of Internal Combustion Engine Top Compression Ring

• DOI: 10.1115/1.4035282
• 发表时间: 2017-06-01
• 期刊: JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME
• 影响因子: 1.5
• 作者: Baker, C.;Theodossiades, S.;Fitzsimons, B.
• 通讯作者: Fitzsimons, B.

Nanoscale elastoplastic adhesion of wet asperities

• DOI: 10.1177/1350650112472142
• 发表时间: 2013-01
• 期刊: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
• 作者: W. Chong;M. Teodorescu;H. Rahnejat

Effect of compression ring elastodynamics behaviour upon blowby and power loss

• DOI: 10.4271/2014-01-1669
• 发表时间: 2014-04
• 作者: C. Baker;R. Rahmani;Ioannis Karagiannis;S. Theodossiades;H. Rahnejat;Alan Frendt