Research On Design Method Of Piston Skirt Profile

Tribology characteristics of the piston skirt is the key issues that have much influence to the design of the modern internal combustion engine's piston. Many research work were carried out to find a solution for a long time, unfortunately, the main issues were not be resolved totally. In order to obtain the final tribology design of piston skirt, large quantities tests were done and many experiences were used to improve design little by little in traditional way. Obviously this method can not meet the requirement of design of the current piston.In this paper, based on the theory of piston secondary motion, Calculated by using the AVL Glide. The parameters, which influence the performance of the piston skirt lubrication including the thermal deformation of the piston and cylinder, the elastic deformation capacity of piston,can be optimized using this mathematical model. Through the analysis of the simulation results, then verify the correctness of the method, a assessment method was able to be obtained to provide more baseline data for the piston design. Then a reasonable skirt profile will be designed for a new one. To finish this purpose, author did the following works:(1)The piston skirt profile has been analysised, including the design factors of the skirt longitude profile, profile curve fit method and piston transversal profile fit method was introduced.(2)With a mature model diesel engine as an example, the development process of a piston skirt has been Introduced, including the data preparation, the work Situation of cylinder, calculation of piston stiffness matrix, the thermal boundary conditions of piston and cylinder. Then the temperature field and deformation of piston and cylinder has been got. finally the piston movement and lubrication conditions has been got.(3)The factors of impact the skirt profile will be studied,including the the skirt profile fitting method, oval degree of selection, the position of bump, the radial reduction, the piston-cylinder gap, as well as the piston pin offset on the impact of movement and friction loss for the design,it provide some reference for new skirt profile designing.(4)Integrated into account the above factors, same reasonable skirt profiles will be designed for the new, the results well be compared with existing models, then this approach is considered feasible, finally the reasonable skirt profile for the new model will be got.