内燃机缸套-活塞环摩擦学研究回顾与展望

内燃机缸套-活塞环摩擦副是一个典型的摩擦学系统,其中含有多种类型的摩擦和磨损,润滑、摩擦、磨损的相互作用十分显著。其摩擦学性能对提高内燃机的可靠性和耐久性,保证内燃机经济、可靠地工作具有决定性的作用。其摩擦学问题的研究一直是人们关注的热点之一。     

阳极PED技术制备活塞环表面陶瓷涂层的研究

在内燃机中,由于摩擦产生的输出功率损失达到20%,可见摩擦磨损是影响内燃机燃油效率的关键因素,其中,活塞环-缸套摩擦副产生的摩擦在内燃机摩擦中占比超过50%,因此,改善活塞环组件的摩擦学性能对提高内燃机性能有着重要的意义。本文对活塞环表面改性、活塞环表面织构、润滑条件等影响活塞环摩擦学性能的因素进行了阐述,着重对利用阳极等离子体电解沉积(PED)技术制备活塞环表面涂层的技术研究进行了介绍,并给出一种利用该技术制备陶瓷涂层的方案供参考。     

活塞环/缸套摩擦副表面织构优化设计方法

应用表面织构改善活塞环/缸套摩擦副的摩擦学特性,是改善其工作经济性、可靠性的最有效手段之一。以质量守恒润滑模型与微凸体接触模型为基础,构建面向织构系统的混合润滑模型。在混合润滑模型的基础上,通过选择合适的活塞环/缸套摩擦副性能评价指标,确定优化活塞环/缸套摩擦副性能的目标函数,结合粒子群优化算法,研究一种在活塞环表面对不同深度微凹坑进行优化设计的新方法。基于大量的数值模拟试验可以发现,具有优化织构深度的微织构可以提高活塞环/缸套摩擦副摩擦学性能,提高了承载能力,降低了摩擦力,验证了所提出的织构优化设计方法是可行的。     

柴油机活塞环表面类金刚石薄膜在模拟工况下摩擦学性能

大缸径、长冲程的大功率柴油机的活塞环-缸套摩擦副易发生异常磨损,使柴油机动力性能丧失,甚至发生拉缸等重大事故,通过先进的表面处理技术可显著改善活塞环-缸套摩擦副的润滑条件,提高活塞环-缸套摩擦副的摩擦学性能。采用阴极电弧离子镀技术在铬-陶瓷复合镀(CKS)活塞环表面制备厚度为7 μm的DLC薄膜,研究CKS活塞环表面的DLC薄膜在柴油机模拟工况下的摩擦学性能。结果表明：在干摩擦、室温贫油和高温贫油的工况下,CKS活塞环表面的DLC薄膜可以显著减小活塞环-缸套摩擦副对摩的摩擦因数,降低缸套的磨损;摩擦过程中DLC薄膜与润滑油的协同润滑作用以及DLC薄膜的石墨化是改善活塞环-缸套摩擦副摩擦学性能的主要原因。     

活塞环——缸套摩擦磨损研究

本文通过摩擦磨损试验仪试验数据,比对出活塞环与缸套在贫油和富油状态的摩擦学特性,揭示出润滑状态是影响活塞环与缸套摩擦副摩擦学特性的关键因素,为产品设计和故障分析提供数据支持。     

摩擦学设计主要是摩擦学系统的设计

在一般意义下的讨论了摩擦学设计,涉及 摩擦学设计的目标和特征。强调摩擦学设计不能仅仅被理解为理解为摩擦副的设计,更能被理解为摩擦,磨损或润滑的设计。介绍了国内在转子－轴承－密－齿轮系统、推力轴承系统、缸套－活塞－活塞环系统、主动磁轴承系统和摩擦学机敏材料系统设计方面所做的一些工作。国家自然科学基金委员会对这些 强有力的经费支持。     

活塞环-缸套摩擦磨损性能的实验研究

活塞环-缸套的摩擦学性能直接影响内燃机的工作性能,降低活塞环的磨损量对提高内燃机的可靠性和耐久性,保证内燃机经济、可靠地工作具有决定性的作用。文中通过实验得出活塞环-缸套在不同工况下的摩擦磨损性能,根据实验结果绘制曲线进行分析,从中找出活塞环-缸套摩擦磨损的有关规律。     

内燃机活塞环-缸套润滑研究的现状与展望

从润滑分析和试验测量两个方面论述了内燃机活塞环-缸套摩擦副润滑研究的现状和进展,讨论并展望了活塞环-缸套摩擦副润滑研究中需要进一步解决的问题.     

纳米金刚石对内燃机缸套─活塞环摩擦学改性研究

纳米级金刚石是应用爆炸法人工合成的具有实用价值的纳米材料,它具有一系列特殊的物理和化学特性。本文针对车用内然机缸套-活塞环摩擦副磨合期内的工作特点,利用金刚石的特殊性能,对其进行摩擦学改性研究。通过内燃机的磨合与摩擦学改性的有机统一,来实现控制缸套-活塞环的摩擦学行为,延长其使用寿命的目的。     

缸套温度对活塞环润滑的影响

内燃机摩擦副的摩擦学性能对整机性能和可靠性有重大的影响。低摩擦技术的开发和应用能有效的降低摩擦功耗,提高内燃机的工作效率,其中活塞和活塞环的摩擦损失所占比例最大,所以本课题通过在保证缸套平均温度相同的情况下,尝试不同的平均温度分布方式,研究有利于降低活塞环摩擦功耗的分布方式。在合适的温度分布的情况下,可以使润滑效果达到一个良好的状态,从而提高热效率,对内燃机产生较为积极的影响。     

内燃机活塞环组密封性能研究

为检验活塞环的密封性,进一步研究其摩擦学性能,建立内燃机环组密封数值仿真模型,模型中考虑气室体积、泄漏面积、内燃机运转工况和气室温度变化项等因素对活塞环密封性能的影响.以PA6-280柴油机为例,对活塞环组的密封性能进行仿真计算.结果表明,磨损对环组的密封性能影响很大,而工况对活塞环的密封性影响不是很明显;气室温度变化项对活塞环漏量影响较大,设计时不容忽视.     

Functional properties of microstructured cylinder liner surfaces for internal combustion engines

Internal combustion engines are still of major importance as propulsion systems. To fulfil future market and legislative demands it is necessary to improve engine performance, reduce fuel consumption, and limit exhaust emissions. Mechanical and thermodynamic losses, wear, and the emissions caused by lubricating oil combustion are principally influenced by the tribological behaviour of the piston assembly. The trend towards compact engines with high power densities and increased thermomechanical loads increases the importance of this tribological system and requires new approaches. One promising possibility is the utilisation of liner surfaces with specially machined microstructures. This paper describes a comparison between a conventional liner surface and a laser‐structured liner as regards their tribological behaviour. Measurements of wear as well as of oil film thickness and friction force in operation have been carried out. The results show better tribological behaviour for the laser‐structured liner surface than for the conventional plateau‐honed surface. This leads to lower fuel consumption and less wear.     

多缸内燃机缸套-活塞系统摩擦学与动力学耦合问题的研究

从理论上对多缸内燃机缸套-活塞系统摩擦学与动力学的耦合问题进行了研究。在纠正了到日前为止被广泛引用的活塞二阶运动方程中的错误的基础上,给出了多缸内燃机缸套-活塞系统摩擦学与动力学耦合问题的数学模型。在该模型中,首次在计算活塞二阶运动时考虑了连杆惯性力的影响。并对影响缸套-活塞系统摩擦学行为的主要动力学因素做了深入的论述。最后讨论了缸套-活塞系统摩擦学与动力学之间的耦合作用对活塞侧推力、作用在连杆和主轴承上的力的影响进行了讨论,并据此对它们的传统计算模型作了修正。     

Contemporary challenges of soot build-up in IC engine and their tribological implications

Confronted with the contemporary challenges of maximising energy efficiency with minimal impact on the environment, the automotive industry has developed various technologies to tackle them. Most of these technologies, however, have wider implications on the tribological performance of the automotive engines due to resultant soot build-up. This paper reviews the effects that attempts by stakeholders to satisfy requirements for reduced fuel consumption, reduced emissions and extended service intervals have had on increasing soot levels to an extent that can lead to engine component failure. Three areas have been identified that have either not been explored or not widely explored in the study of automotive soot namely: numerical simulation and modelling of soot wear, soot effects on wear of actual engine components and the wear and friction performance of non-metallic materials used in internal combustion engines. A paper-grading system is also utilised to present an overview of how sooty oil-related research covers various areas.     

The piston ring or the piston seal?

Improvement in the efficiency of piston compression rings is considered. By taking account of the gas dynamics in determining piston-ring geometry and developing a system of piston rings and piston seals for various internal combustion engines, their basic performance and environmental characteristics may be improved.     

Analysis and computation of the oil film thickness between the piston ring and cylinder liner of an internal combustion engine

A study of the essential features of piston rings in the cylinder liner of an internal combustion engine reveals that the lubrication problem posed by it is basically that of a slider bearing. According to steady-flow-hydrodynamics, viz. the oil film thickness becomes zero at the dead centre positions as the velocity, U = 0. In practice, however, such a phenomenon cannot be supported by consideration of the wear rates of pistion rings and cylinder liners. This can be explained by including the “squeeze” action term in the hydrodynamic theory, viz. .This article introduces the equations of the above theory along with the viscosity variation over the piston stroke length; the piston ring profile is assumed as a double parabola with a central straight portion.The results of this analysis as applied to internal combustion engines are presented and compared with other earlier analysis.     

The use of copper to prevent scuffing in diesel engines

The use of copper-plated cast iron rings is suggested as a means of preventing “scuffing” in internal combustion engines and tests are described which support the practicability of this suggestion. The tests indicate that all the rings on a piston must be copper-plated to prevent rapid wear of the copper should an unplated ring scuff the liner.     

内燃机轴系扭转振动综述

根据目前内燃机发展趋势,确定了内燃机振动在内燃机设计中的重要地位。然后总结出内燃机轴系振动的形式,同时评析了内燃机轴系振动的力学模型、分析计算方法及近年来的最新研究动态。     

Friction Power Loss Simulation of Internal Combustion Engines Considering Mixed Lubricated Radial Slider,Axial Slider and Piston to Liner Contacts

Different types of mixed lubricated contacts are present in internal combustion engines. These are several radial slider bearings; for instance, in main bearings; big end, small end, and piston pin bearings; as well as axial slider bearings and piston–liner contacts. Phenomena such as friction power loss and wear as well as acoustic excitation and oil consumption of the overall lubrication system are mainly affected by these contacts. Therefore, the simulation-based investigation of oil film–lubricated contacts is important during the development process of internal combustion engines. Due to the highly nonlinear interactions, the applied mathematical models have to consider the dynamics of the overall flexible body system in addition to the detailed properties of the contacts and the lubricant itself.

This work outlines both the theory of the separated mathematical models and their coupling. The large number of nonlinear contacts, which is possible to consider when applying the presented coupling approach, is emphasized. Furthermore, application of a friction power loss analysis for an in-line four-cylinder internal combustion engine is described.