Dynamics Analysis And Structural Optimization Of Camshaft Based On Weight-Lightening

The weight-lightening of automobile is one of the effective measures to deal with issues such as energy consumption and environmental pollution.The engine camshaft is one of the most massive and critical components in a valve train.It strongly depends on the camshaft design whether an engine has the superior fuel economy,reliable power,low noise and good vibration control.This paper is based on the project of Dynamics Analysis and Structural Optimization of Camshaft Based on Lightening Weight,a self-developed project from Shanghai Volkswagen Powertrain Co.,Ltd.,This work focused on the design of a certain-brand engine camshaft under the premise of meeting the reliability of the mechanical properties,to achieve the camshaft structural optimization based on the weight-lighting study.The main work of this thesis is as follows:(1)A simplified three-dimensional model of the original engine valve train was established.The dynamics analysis of the valve train was completed based on the multi-body dynamics model.The movement of the camshaft and other components of the valve train was studied and the rationality of the simplified model was verified.(2)The transient dynamics analysis and fatigue life study of the camshaft was completed,based on the finite element model,Miner’s theory of linear cumulative damage and discrete principles of substeps.It proved that the reliability and fatigue life of the original camshaft structure were far higher than the actual requirements,resulting in material waste.(3)Optimization of the structure of the original camshaft was completed based on the optimization algorithm(topology optimization),structural process requirements and equivalent static load algorithm,and the mass production process of the camshafts was designed to realize the lightweight research of the camshaft.(4)The reliability of the mechanical structure of the optimized camshaft was verified,based on transient dynamic analysis;The reliability of the optimized camshaft was verified,based on Miner’s theory of linear cumulative damage and discrete principle of the substeps.The simulation results showed that the fatigue life of the optimized camshaft is 4.102×108 times,which is much higher than the service life specified in the "Motor Vehicle Mandatory Scrap Standards Regulations ";It was verified that the optimized camshaft had a reasonable and reliable service life,based on the torsion fatigue test of the camshaft.Using the engine test bench to check the engine’s power-to-mass ratio of the optimized camshaft,which is 2.01% higher than before the optimization.The results validated that the optimized camshaft can improve engine efficiency.This work can provide a platform for the lightweight research of the same type of products.