Design And Dynamics Analysis Of Timing Silent Chain Drive System For A Gasoline Engine

With the continuous development of China's economy,people's material living standards have gradually improved,the annual production and sales of automobiles in our country are also growing rapidly.However,the design and production technology of high-end automotive parts have been monopolized by developed countries such as the United States,Germany and Japan for a long time.The timing system is an important part of valve train of automobile engine,timing silent chain drive system is widely used because of its low noise,high transmission accuracy,high transmission efficiency and the same life as engine.The design and dynamic simulation analysis of the timing silent chain drive system is carried out according to the parameter data provided by the main engine manufacturer.Firstly,the research status of the timing chain drive system at home and abroad is introduced.In order to design and simulate the timing system conveniently next,the gas exchange process of engine valve train,the working principle of the timing system,the meshing mechanism of the silent chain and the motion characteristics of the timing system are described in detail.Then,the working chain plate,working guide plate,sprocket,guide and hydraulic tensioner of the timing chain drive system are designed,selected and modeled in three dimensions according to the parameter data provided by the main engine manufacture.Next,the dynamic model of the timing chain drive system designed in this paper is built in RecurDyn,the multi-body dynamics simulation analysis of the timing system with crankshaft sprocket speed of 2000r/min,4000r/min and 6000r/min is carried out respectively.The results of the simulation analysis show that the first subsystem runs very steady and the trajectories of the chains almost coincide,there is slight fluctuation in some parts of the chain when the second subsystem runs,but it is within a reasonable range;the transmission ratio error of the timing system is far less than 1%;the maximum tension of the chain appears in the second subsystem when the crankshaft sprocket speed is 6000r/min,which is 1287.48 N,less than the fatigue breaking load of the chain 1800N;the hydraulic tensioner is not separated from tensioning guide when the system is running,which means matches well with the system;the contact force between chain plate and sprocket varies regularly with the operation of the system.The above analysis results prove that the timing system designed in this paper meets the design requirements.The position of injector was designed after completing the design of the timing system and multi-rigid body dynamics simulation analysis.Through co-simulation of the ParticleWorks and RecurDyn,it is observed that all parts of the timing chain drive system are fully lubricated during operation,which proves that the position of injector designed in this paper meets the design requirements.Finally,the service life of the working chain plate is predicted by performing the rigid-flexible coupling multi-body dynamics analysis of the timing chain drive system,which proves that the timing chain designed in this paper can meet the requirements of the same service life as the engine.The research results of this paper have important guiding significance for the design and development of the timing silent chain drive system with independent intellectual property rights in our country in the future.