【作者】 杨波；

【导师】 宋希庚；

【作者基本信息】 大连理工大学 ， 动力机械及工程， 2008， 硕士

【摘要】 活塞作为内燃机的关键零部件之一,它的工作情况直接关系到高速内燃机的工作可靠性和使用耐久性,同时直接影响到内燃机的排放性能。活塞的结构和所处的工作环境十分复杂,在工作状态下受到高压燃气压力、高速往复运动产生的惯性力、侧向压力和摩擦力等周期性载荷作用,产生机械应力和机械变形。高压气体燃烧产生的高温使活塞顶部乃至整个活塞温度很高,且温度分布很不均匀,导致活塞产生热应力和热变形。因此,在设计阶段对活塞温度场进行有限元分析,并且采取有效的措施降低其热负荷是非常必要的,以便改进活塞机构,提高其工作可靠性。本文在大连柴油机厂的帮助下,利用硬度塞测温法获得了额定工况下活塞表面关键点的温度值;应用三维建模软件Pro/E对该厂的6110型柴油机活塞进行三维建模,然后将活塞的三维模型导入到有限元分析软件ANSYS中进行数值模拟,在实测温度值的指导下反复计算,得到额定工况下活塞三维稳态温度场;在此基础上,并对活塞的内腔进行底喷冷却以达到降低活塞热负荷的目的。除此之外,还对活塞油冷却方式进行对比,得出连杆小端的喷油冷却对活塞燃烧室中心部位温度降低明显;而对降低热负荷较大的活塞顶部以及第一环槽的温度不明显。要想更好的改善活塞的热负荷,应该采用固定在机体上喷嘴配合活塞的冷却通道进行活塞的冷却方法。通过以上有限元分析、温度场分析及底喷冷却研究,为该型柴油机活塞的改进提供一定的理论依据,同时也为大连柴油机厂生产的其他系列产品的有限元分析计算提供了参考。更多还原

【Abstract】 The piston is one of the main parts of the internal combustion engine, its operation condition concerns working dependability and use durability of high-speed internal combustion engine directly. At the same time, it influences the emission performance of the internal-combustion engine directly. The structure of piston and its working environment are very complicated. In working condition, the piston stands periodic load, such as high gas-pressure, inertia-pressure, side direction pressure and frictional force, which produce mechanical stress and distortion. The burn of high-pressure gas produced high temperature makes piston top surface and whole temperature of piston very high. Furthermore the temperature distribution is asymmetry, causing the piston to produce thermal stress and thermal distortion. So during the course of designing, it is very necessary to calculate and analyze the piston temperature field, take effective measures to reduce the thermal stress .so to improve the structure of piston and its working dependability.With the help of Dalian Diesel Engine Company, this paper adopts rigidity-plug temperature measurement method to text key point temperature value Of piston of 6110 Diesel Engine. Then builds the 3-D model of 6110 diesel engine piston with the 3-D software Pro/Engineer from Dalian Diesel Engine Company. The model is imported to the ANSYS and made the numerical simulation of temperature field of piston under the guidance of practical temperature value, then concludes the distribution of 3-D temperature field of piston under standard operation condition; On the basis of analysis , using bottom ejecting cooling of piston reduce the thermal stress of pistonIn addition, the paper makes a contrast with oil cooling method of piston, and concludes that it is obvious that the ejecting oil form connecting-rod small end cools the center position temperature of combustion chamber, but it is not obvious to cool the top surface of piston and the first ring groove. In order to reduce the thermal stress, it is better to make use of injector fitted in the block and cooling passage together to cool the piston.Through the finite element analysis and temperature field analysis and bottom ejecting cooling research, this paper offers certain theoretical foundation for development and improvement of diesel engine piston, also offers the parameter for the finite element analysis of other series of products which are produced in the Dalian Diesel Engine Company.更多还原