内燃机分区差异织构润滑减摩与机油消耗机理及其协同控制研究

The behavior of lubrication-friction and oil-consumption of the cylinder liner-piston ring system is the key to energy saving and emission reduction for internal combustion engines, and the necessity of balancing the Trade-off relationship emerges as the service condition becomes increasingly and extremely severer. Based on the flexible laser micro process technology, a new method in virtue of divisional and complex textures made on the liner surface is put forward, to meet the main diversified tribological functional requirements of multiple areas along the stroke, implement the functional design and setup of matched pluralistic complex-texture, and realize the collaborative optimization of friction-reduction and oil-control. The intensive research centers around two key scientific issues, which are the anti-friction effect and the oil consumption mechanism of the textured liner-ring pair under its extreme service condition. Considering the effect of heat atmosphere of combustion inside the cylinder comprehensively, explore the regional distribution characteristics of lubrication mode within the stroke, the lubrication mechanism of surface textures, and the principle of oil consumption through evaporation and transport. Eventually, theoretical models about the three dimensional lubrication and friction on account of the heat transfer as well as oil consumption of surface textured liner-ring are established. Through the numerical simulation and experimental validation, the influence of shape, distribution and complex of textures on the lubrication performance and oil consumption is studied. As a consequence, the design criteria of functional partition and texture recombination for the liner surface are formed, which lays the theoretical foundation and scientific basis for the design of the tribological system for environment-friendly engines.

缸套活塞环系统的润滑减摩与机油消耗行为是内燃机节能减排的关键，而在日趋苛刻的极端服役工况下二者Trade-off关系尤甚。基于项目组自主研发的特殊激光微加工技术与装备，提出缸套表面分区差异织构新方法，满足行程内多区域差异化的摩擦学主导功能需求，实施优化匹配的多元化复合织构功能化设计与设置，实现减摩与控油性能的协同优化。围绕极端服役工况条件下织构化缸套活塞环的润滑减摩表面效应与机油消耗机理两大关键科学问题，展开深入研究。综合考虑缸内燃烧热氛围的影响，建立织构化缸套活塞环三维传热润滑摩擦及其机油耗理论模型，研究行程范围内润滑模式的区域分布特性、表面织构的润滑减摩机理，机油蒸发及输运消耗机理。经数值模拟与实验验证，总结织构形貌、空间分布与复合型式对润滑性能与机油消耗的影响规律，最终形成缸套表面功能化分区与差异织构方案设计准则与体系，为环境友好型内燃机摩擦学系统设计奠定理论基础和科学依据。

缸套-活塞环系统的润滑减摩与机油消耗行为是内燃机节能减排的关键，而在日趋苛刻的极端服役工况下二者Trade-off关系尤甚。随着机械零件表界面科学的不断发展，利用微纳加工手段在机械表面加工出规则微观形貌的表面织构技术应运而生，其在内燃机缸套-活塞环摩擦系统中具有巨大的应用潜力。课题研究过程中，首先建立织构化缸套-活塞环非高斯表面润滑摩擦理论模型，研究实际缸套表面粗糙度和微织构的耦合作用，确定在粗糙度呈小负偏态分布的原始缸套表面上加工凹坑织构能够有效提高缸套-活塞环的润滑性能，进而对表面织构在多种苛刻工况下的适应性开展研究，发现在极端多变工况下，织构化缸套能够增强缸套-活塞环摩擦副对工况变动的适应性。以此润滑模型为基础，提出活塞环仿桶形新型织构型式，发现这种织构型式可以增强油膜的承载能力，提高缸套-活塞环的润滑性能，降低摩擦。其次，建立织构化缸套-活塞环机油消耗理论模型，研究织构形貌和参数对机油消耗性能的影响，并通过发动机机油消耗试验测试，对织构化缸套机油耗理论计算结果进行验证。再次，开展内燃机缸套表面激光微织构加工过程的数值模拟与试验研究，研究激光参数对织构形貌参数的影响规律，实现缸套表面激光微织构的主动设计，进而面向减摩和控油协同优化需求，对缸套表面进行功能化分区，设计分区差异织构方案并进行激光微织构加工；同时通过对激光微加工工艺的研究，掌握微坑、微孔的加工技术，为在发动机上的进一步应用打下基础。最后，开展缸套织构化发动机台架性能试验研究，对倒拖扭矩、燃油消耗和机油消耗进行对比分析，结果表明：在缸套表面进行分区差异织构，对缸套活塞环的润滑摩擦性能影响不同；通过对缸套上止点和活塞裙部接触区域进行差异织构，能够有效提高缸套-活塞环的润滑摩擦性能，降低整机燃油消耗和机油消耗，达到了减摩和控油协同优化的效果。项目成果在多家企业得到成功应用，成果荣获教育部技术发明二等奖和江苏省科学技术二等奖。