发动机配气机构动力学分析及优化

哈尔滨工业大学工学硕士学位论文AbstractValve train is an important part in the internal combustion engine,whether itsstructure is appropriate or not will directly affect the engine's economicperformance,noise pollution,vibration and working reliability.Valve pair'sworking condition is not only a direct scale of the valve train's state,but also akey factor to work on the valve pair's impact fatigue wear.This thesis analyzesall the factors that affect the valve pair's impact fatigue wear both on theory andexperiment.Moreover,it also presents the improving method accordingly.So,the dynamic analysis of valve train plays an important role in the enginedesigns.The methods in common use include Single-Mass Model,Multi-MassModel and Finite Element Method.With a view to the result's veracity and theuse of computation,the Multi-Mass Model is often used to analysis the valvetrains dynamic performance.This article discuss the computation and analysisof the Multi-Mass Model,and a kind of multi-mass model was established.With regard to the impact fatigue wear between the valve and the valve seat(it's the origin of noise pollution in the valve train,and it always causes the valvetrain disabled.)a valve friction and wear test-bed was devised.It take CA488valve train as its structure frame,and it can be used to test CA488,CA6102.CA6110 valve train's valve impact fatigue wear.To analyze the testing result on theory,a new kind of multi-mass dynamicmodel was presented.The model aims at the test-bed factual structure,givesattention to CA6102's structure trait.Reasonable centralized mass distributionsis used to replace the mass of moving accessory,"Hertz"contact method is usedto calculate the stress and deformation,more simple and reasonable origin ofcoordinate is chosen for the model calculation.Applied to the model presented,the dynamic performance of valve train of the test-bed is calculated,the result ofthe calculation is compared with the testing result of the test-bed.At the sametime,the relationship between max seated impact force and Cam speed and valveclearance is calculated.Key Words Engine;Valve train;Dynamic Analysis