Lightweight Design And Modal Test And Analysis Of Crankshaft Of DK4-A Diesel Engine Based On Multibody Dynamics

Lightweight design of automobiles is one of the important measures to achieve energy saving of automobiles,which has attracted extensive attention of R&D personnel.Crankshaft is an important part of internal combustion engine,which is the heart of automobile.It is of great significance to lightweight design of crankshaft structure.This topic carries on the lightweight design to the crankshaft,and has analyzed the reliability of this lightweight design scheme from many aspects.The research of this subject is as follows: Based on the crankshaft design of DK4-A diesel engine,the crankshaft was lightweight designed under the condition that the shape and size of the crankshaft were kept unchanged.Based on the theory of response surface analysis,the lightweight design scheme was determined,and the weight of the lightweight crankshaft was 20.15 kg,which was 2.76 kg less than that of the original crankshaft;Build a crankshaft dynamic balance simulation experiment platform,get the lightweight crankshaft has better vibration characteristics and lower energy consumption than the original crankshaft;based on the load data of the lightweight crankshaft main journal and connecting rod journal measured by simulation means,get that the load of the lightweight crankshaft main journal and connecting rod journal is smaller than the original crankshaft;use the relevant data measured by simulation and the knowledge of fluid lubrication,The lubrication characteristics of lightweight crankshaft are obtained to meet the service requirements,and the strength of lightweight crankshaft is analyzed by Ansys Workbench,and some structural optimization is carried out for its weak position.The strength of lightweight crankshaft meets the service requirements,and the strength of the crankshaft increases after some structural optimization;Based on the theory of multi-body dynamics,the dynamic analysis of lightweight crankshaft by Adams is carried out.The results of multi-body dynamics analysis are similar to those of strength checking.The errors of piston displacement,velocity and theoretical calculation are 1.06% and 2.39% respectively.That is to say,the calculation model is reliable;The fatigue analysis of lightweight crankshaft is carried out by using Ansys nCode.The results show that if the crankshaft works 8 hours a day and 10 months a year,the crankshaft can be used for 10.43 years to meet the life requirements of crankshaft;In order to obtain the vibration characteristics of lightweight crankshaft and provide guidance for further reducing the vibration of crankshaft,two calculation methods are used to carry out modal analysis of lightweight crankshaft.The maximum error of the two methods is 3.73%.Thus,not only the vibration characteristics of lightweight crankshaft are obtained,but also the accuracy of the calculation model is verified.Increase the reliability of the analysis results;...