气缸孔失圆变形特征对柴油机机油消耗的影响机理

The main source of diesel engine particulate matter (PM) emission is come from oil which flees to the combustion chamber through piston ring-cylinder liner friction pair. It can coordinate the friction pair seal performance and friction loss by controlling cylinder bore circumferential deformation and improving the adaptability of piston ring on the deformed cylinder.Meanwhile, it also can effectively control the PM emission and fuel consumption. Therefore, taking a high pressure common rail diesel engine as a research object, systematic study will be carry out on the law ofcylinder bore circumferential deformation and piston ring deformation under the conditions of multi-physics coupling by using a method of test and simulation.The different order deformation law and work surface characteristic of cylinder bore will be studied at different operating conditions by Fourier analysis method. Theadaptive relationship between piston ring group and different orderdeformationof cylinder borewill be studied.The influence of piston ring structure parameters on the cylinder bore maximum deformations limit at different harmonic orders will also be explored. In addition,an evaluation method that cylinder bore critical deformation caused by piston ring loss its contact to the cylinder will be came up.The oil consumption simulation model will be build based on the test which will be conducted by using sulfur tracer method and the theory of dynamic deformation of cylinder liner, piston ring group dynamics and the theory ofin-cylinder oil loss. The relationships and influence weight that different deformation characteristics of cylinder bore, deformed cylinder bore and the adaptability of cylinder ring on the oil consumption will be studied systematically, and the oil consumption mechanism will be revealed. This research will provide a scientific basis for controlling oil consumption, reducing PM emission and optimizing friction performance.

机油经活塞环-缸套摩擦副窜入燃烧室燃烧是柴油机微粒排放（PM）的主要来源。控制缸孔失圆，提高活塞环对失圆气缸的适应性，可协调摩擦副密封性能与摩擦损失的矛盾，并在柴油机内部实现PM与燃油耗的有效控制。以高压共轨柴油机为研究对象，采用测试和仿真分析结合的方法，系统研究多物理场耦合下缸孔变形与活塞环变形的规律；应用傅里叶分析方法，研究不同工况下的缸孔各阶次变形规律和工作型面特征，研究不同工况下活塞环组与各阶次缸孔变形的适应关系，研究活塞环结构参数对各阶次缸孔最大变形限值的影响关系，确定活塞环对气缸失去接触的临界缸孔失圆变形评价方法；采用含硫示踪法进行机油消耗试验，结合缸套动态变形、活塞环组动力学、缸内机油耗损等理论，建立机油消耗仿真模型，系统研究不同缸孔变形特征、失圆缸孔与活塞环适应性对机油消耗的影响关系和影响权重，揭示缸内机油消耗机理，为控制机油消耗、减小微粒排放以及优化摩擦性能提供科学依据。

随着国内外军用及民用动力的强化程度不断提升，发动机缸内爆发压力提升，导致热负荷及机械负荷大幅增加，在高强度工作条件下的气缸变形量显著增加。而机油经活塞环-缸套摩擦副窜入燃烧室燃烧是柴油机微粒排放（PM）的主要来源，当活塞环弹力无法补偿缸孔失圆时，将会导致发动机动力性、排放特性以及振动特性。受热流固多物理场耦合作用的影响，缸套工作变形呈现非线性特征，缸套变形以及控制技术一直是研究的难点。因此研究缸孔失圆规律与特征以及对密封与摩擦性能的影响规律，提高活塞环对失圆气缸的适应性，可以有效改善缸套-活塞环摩擦副密封性能与摩擦损失的矛盾，并在柴油机内部实现对PM与燃油耗的控制。. 课题以高压共轨柴油机为研究对象，开发了缸套动态变形测试系统，采用测试和仿真分析结合的方法，系统研究了多物理场耦合下缸孔变形与活塞环变形的规律；应用傅里叶分析方法，分析了热态、热态预紧、热态预紧过盈（仅对干式缸套）、热机耦合和热机耦合过盈（仅对干式缸套）不同加载条件下的缸孔各阶次变形规律和特征；分析了不同加载条件下活塞环组与各阶次缸孔变形的适应关系与影响关系，总结了活塞环对气缸失去接触的临界缸孔失圆变形评价方法；分析了缸孔各阶次变形对活塞环密封与摩擦性能影响规律。设计了含硫示踪法机油消耗试验，结合缸套动态变形、活塞环组动力学、缸内机油耗损等理论，建立了机油消耗仿真模型，系统分析了活塞环结构对窜气量及摩擦损失功率的影响。.获取了不同加载条件下的缸孔各阶次变形规律和特征研究成果，以及缸套-活塞环摩擦副对润滑油消耗、窜气量及摩擦损失功率影响规律的研究成果，为控制机油消耗、减小微粒排放以及优化缸套-活塞环摩擦性能提供科学依据。