活塞组工作性能多目标优化的研究

发布时间：2018-06-12 09:26

本文选题：内燃机 + NVH　；参考：《浙江大学》2015年硕士论文

【摘要】：内燃机NVH性能的优化是目前汽车舒适性提升中重要的一个环节,而活塞是内燃机的主要运动件之一。目前的研究表明,活塞的工作性能不仅对内燃机的动力性、经济性和排放性能有很大的影响,而且对内燃机的NVH性能也有非常突出的影响。因此,研究活塞组的动力学特性,优化其工作性能对改善内燃机NVH性能有重要的意义。本文以内燃机活塞组为研究对象,建立了活塞及活塞环组动力学模型,对活塞组的二阶运动、窜气、机油消耗以及活塞敲击问题进行了深入的研究。建立了模拟活塞二阶运动的仿真分析模型。通过建立活塞连杆机构的动力学模型、有限元模型与润滑模型,对活塞进行综合仿真分析。研究了活塞二阶运动特性、接触力、敲击能及摩擦损失,在分析的基础上对活塞进行结构优化,有效改善了活塞的二阶运动。对活塞环组特性进行研究,建立了活塞环组动力学模型。模型主要包括力学模型、气体流动模型、润滑模型及机油消耗模型。对环组的运动状态、润滑状态、窜气量以及机油消耗等工作性能进行了深入分析。在活塞环组动力学模型的基础上,结合基于综合评分法的多目标正交设计,研究了活塞环开口的结构参数对活塞组窜气及机油消耗的影响,并在研究的基础上对活塞环开口进行结构优化,在控制窜气量与机油消耗上取得了较好的效果。将活塞动力学模型中获得的敲击载荷施加到内燃机有限元模型上,建立活塞敲击模型,对活塞敲击导致的机体表面振动开展了研究。其中,通过自由模态试验验证了发动机有限元模型的准确性,通过倒拖试验验证了活塞敲击模型的可靠性。最后通过敲击模型研究了活塞配缸间隙对机体表面振动的影响,对该发动机目前的活塞配缸间隙方案做出了评价。
[Abstract]:The optimization of NVH performance is an important step in the improvement of vehicle comfort, and the piston is one of the main moving parts of internal combustion engine. The current research shows that the performance of piston not only has a great influence on the power, economy and emission performance of internal combustion engine, but also has a very prominent effect on the performance of NVH of internal combustion engine. Therefore, it is important to study the dynamic characteristics of piston group and optimize its performance to improve the NVH performance of internal combustion engine. Taking the piston group of internal combustion engine as the research object, the dynamic model of piston and piston ring group is established in this paper. The problems of oil consumption and piston percussion are deeply studied. A simulation analysis model is established to simulate the second order motion of piston. By establishing the dynamics model, finite element model and lubrication model of piston linkage mechanism, the comprehensive simulation analysis of piston is carried out. The second order motion characteristic, contact force, percussion energy and friction loss of piston are studied. The structure of piston is optimized on the basis of analysis, and the second order motion of piston is improved effectively. The dynamic model of piston ring group was established. The model includes mechanical model, gas flow model, lubrication model and oil consumption model. Based on the dynamic model of piston ring group and the multi-objective orthogonal design based on comprehensive scoring method, the working performance of ring group, such as movement state, lubricating state, gas channeling and oil consumption, is analyzed in depth. The influence of the structure parameters of piston ring opening on gas channeling and oil consumption of piston group is studied, and the structure optimization of piston ring opening is carried out on the basis of the study. Good results have been obtained in controlling gas channeling and oil consumption. The percussion load obtained from the piston dynamics model is applied to the finite element model of internal combustion engine, and the piston percussion model is established. The vibration of the body surface caused by the piston percussion is studied. The accuracy of engine finite element model is verified by free mode test, and the reliability of piston percussion model is verified by backward drag test. Finally, the impact of piston cylinder clearance on the surface vibration of the engine is studied by tapping model, and the current piston cylinder clearance scheme of the engine is evaluated.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK423

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