Research On Dynamic Characteristics Analysis Of Valve Group Of Diesel Engine

Valve train is an important part of the engine, its function is to achieve the ventilationprocess of the valve train. According to the requirements of the work cycle in the cylinder andthe ignition sequence, timed to open and close the intake and exhaust valves of each cylinderto ensure cylinder to inhale fresh air and exhaust combustion exhaust gas timely. Whendesiging the valve train of diesel engine, the normally reliable work of the valve train must beguaranteed, so it is necessary and important to research the dynamic characteristics of thevalve train.In this paper, the valve train of certain diesel engine was taken as research subjects, itsdynamics was analyzed specifically. Firstly, according to the dynamics theory of the valvetrain, the single-degree-of-freedom dynamic model and the multi-degree-of-freedom dynamicmodel of the valve train were established, and then use formulas to estimate the parameters inthe models, at last, MATLAB software was used to fit the cam profile data to gain the law ofmotion of the cam follower of the original data.At the same time AVL software was also utilized for valve train dynamics analysis in thispaper, Excite Timing Drive module was used to establish the dynamic model of the valve train,introduced the method of finite element analysis to determine the parameters of the models,obtained the dynamics of the valve train components and then evaluated the results. Thenresearch the impact of the engine speed, valve clearance, valve spring stiffness parameters onthe dynamics of the valve train to find the main factor to cause the flutter of valve spring.Finally, the flutter of valve spring was theoretical analyzed in this paper, and optimizeddesign was proposed, besides, the valve spring was redesigned. The simulation results showthat the flutter of the valve spring was inhibited to some extent with the new design of the valve spring.