缸套变形与机油颗粒对活塞环-缸套摩擦润滑影响的研究

发布时间：2018-01-18 10:15

本文关键词：缸套变形与机油颗粒对活塞环-缸套摩擦润滑影响的研究　出处：《太原理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：缸套-活塞环这对摩擦副作为发动机内最重要的摩擦副之一,其工作性能的好坏直接影响到发动机的整机性能。然而在目前缸套-活塞环系统摩擦润滑的研究中,多数研究者将缸套内表面假设为理想圆柱壳进行仿真模拟,很少有考虑到缸套动态变形对油膜润滑的影响作用;同时在分析缸套-活塞环间润滑油膜分布特性时,往往将润滑油液等效为不含杂质成分的理想流体,但是基于以上假设所得到的结果与实际润滑特性相差较大。因此,本文采用数学模型计算与有限元仿真相结合的方法,将缸套动态变形和机油固体颗粒的影响耦合至润滑模型中,对缸套-活塞环摩擦润滑过程进行了多因素影响下的研究探索。以煤制柴油(F-T柴油)、生物柴油和甲醇柴油(M15)三种具有不同燃烧特性的替代燃料作为一种可控的缸套动态响应激励源,对比分析了不同的缸内燃烧过程对缸套动态变形可能产生的影响。本文首先建立了活塞在缸套内侧向运动的活塞动力学模型,综合考虑缸内燃气压力与活塞组件往复惯性力的影响,计算获得了活塞侧击力曲线及活塞的侧向位移曲线。基于上述动力学模型,结合有限元分析软件Patran/Nastran模拟了缸套被燃气冲击与活塞侧向敲击引起的动态响应。通过缸套有限元动态仿真获知,缸套在激励下发生了包含模态响应成分的动态变形,而且进一步研究发现缸套动态变形的幅值非常接近缸套-活塞环摩擦副表面粗糙度的量级,表明缸套动态变形会对润滑油膜的形成与分布造成直接的影响,为缸套-活塞环间润滑油膜厚度计算和摩擦特性的研究引入了新的影响因素。然后依据二维平均Reynolds方程,以微凸体接触模型及Reynolds边界条件为基础,建立了缸套-活塞系统摩擦、润滑行为和动力学行为耦合的流体动压润滑数学模型。其中考虑了缸套动态变形与缸套-活塞环间油膜润滑耦合作用,对比分析了在是否考虑缸套变形影响下运动副之间的摩擦与润滑特性。同时,为了研究液固二相润滑中固体颗粒状态的变化对活塞环-缸套摩擦润滑特性的影响,将颗粒物对油液性能的影响简化为对黏温特性的改变,在一维润滑模型的基础上,引入固体颗粒的浓度和粒径参数,预测分析了缸套-活塞环间液固二相润滑情况。最后在单缸水冷柴油机上开展了一系列台架试验研究,分析了替代燃料燃烧特性、机油固体颗粒浓度在不同运行工况下对缸套-活塞环摩擦润滑特性的影响。采用连续小波变化分析了动态变形相关的缸套振动,基于多分辨率包络小波分析技术研究了与摩擦过程相关的声发射特征信号,试验分析结果与理论预测结论基本吻合,可以为今后内燃机缸套-活塞环间摩擦润滑的研究与工业实践提供了一定的理论指导意见。
[Abstract]:The friction in the engine as one of the most important friction pair of cylinder piston ring, its performance directly affects the performance of the engine. However, in the current research of cylinder piston ring friction lubrication system, most of the researchers will be the inner surface of the cylinder is assumed to be an ideal cylindrical shell is simulated, there is little consideration to the cylinder dynamic deformation effect on oil film lubrication; at the same time in the analysis of cylinder piston ring lubrication film distribution, often the lubricating oil equivalent to ideal fluid does not contain impurities, but the above assumptions based on the results and the actual lubrication characteristics are different. Therefore, this method mathematical model the calculation combined with finite element simulation, the influence of coupling to cylinder and oil lubrication model of dynamic deformation of solid particles in the cylinder piston ring friction lubrication process is carried out Study on the influencing factors of the coal exploration. In diesel fuel (F-T diesel), biodiesel and methanol diesel (M15) three alternative with different burning characteristics of the fuel cylinder as a controllable dynamic response of excitation source, comparative analysis of the combustion process in the cylinder deformation of different possible effects on cylinder dynamic firstly. A dynamic model of motion of the piston to the piston in the cylinder inside, considering the influence of the gas pressure inside the cylinder and piston assembly reciprocating inertia force, the lateral displacement curve and piston swipe force calculations. The dynamics model based on the combination of finite element analysis software Patran/Nastran to simulate the gas cylinder by the piston lateral impact and percussion due to the dynamic response. The cylinder dynamic FEM simulation that the modal response components including cylinder dynamic deformation under the excitations, but also further research The maximum amplitude of the cylinder dynamic deformation is very close to the cylinder piston ring friction pair surface roughness magnitude, show that the dynamic deformation of cylinder will cause a direct impact on the formation and distribution of oil film, research for oil film thickness between piston ring and cylinder liner friction characteristics calculation and introduces new factors. Then on the basis of two dimensional averaged Reynolds equation with boundary condition of asperity contact model and Reynolds as the foundation, established the cylinder piston system friction, fluid lubrication behavior and dynamic behavior of coupled hydrodynamic lubrication model. Considering the dynamic deformation of cylinder and cylinder piston ring between the lubricating oil film coupling, a comparative analysis on whether considering the friction and lubrication of cylinder liner deformation under the influence between the pair. At the same time, in order to study the status of solid particles in liquid-solid lubrication in the change of the piston ring cylinder lubrication The influence of the characteristics, the influence of particles on the oil properties is simplified to viscosity temperature characteristics change, based on one-dimensional lubrication model, the introduction of solid particle concentration and particle size parameters, prediction analysis of cylinder piston ring between liquid-solid lubrication. Finally in the single cylinder water-cooled diesel engine was carried out a series of bench test research, analysis of the combustion characteristics of alternative fuels, effect of particle concentration in oil lubrication performance of piston ring - cylinder liner under different operating conditions. By using the continuous wavelet transform of dynamic deformation of liner vibration related analysis, multi resolution wavelet envelope analysis technology research related with the frictional characteristics of acoustic emission signal based on the analysis of the test results and the theoretical prediction is consistent with the conclusions, the research and practice of industrial lubrication can provide certain theoretical guidance meaning for the future of internal combustion engine cylinder piston ring friction See.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK401

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