Rigid-flexible Coupled Dynamics Simulation Of The Valve Train And Establishment Of Digital Prototype

The diesel engine has been used as the main power propulsion system and primemotor of the auxiliary generator in the ship. People have higher demand for performance ofmodern diesel engine which tends to the way of high power density, low pollution, lowemission, low noise and high reliability. The well gas exchange process is guaranteed by thevalve train which is one of the main mechanisms of the diesel. The intake and exhaustvalves are accurately unlocked and closed according to the fire order and process of eachcylinder. The dynamic performance, economic performance, vibration and noise, emissionindex and service life of the diesel is directly affected by the design of the valves train. As aresult, the valve train should be significantly studied during the research of the diesel.In this article, valve train of6L21/31marine diesel engine is studied by virtualprototype. The3D solid model of valve train has been built by the Pro/E according to theengineering drawing and assembled according to the constraint relations. And then themulti-body dynamics model has been built after importing the model to the ADAMS by theinterface of Mechanism/Pro software and the simulation analysis has been carried on. Thevalve stem and tappet are made into flexible body by ANSYS soft ware. The initial rigidbody has been replaced by flexible body and the simulation analysis has been carried on.Then the multi-rigid body dynamic model and rigid-flexible coupled dynamic model’ssimulation results are compared with theoretical calculation. The6L21/31diesel of virtualprototype is built by the subject of crank and connecting rod mechanism. The conclusionsare obtained after comparison and analysis.(1) The accuracy of the virtue prototype model of diesel has been confirmed accordingto the comparison between the result of simulation and theoretic calculation;(2)The elastic deformation during the realistic process has been confirmed by theanalysis, and it has influence on the movement of valve train. As a result, the rigid-flexiblecoupling simulation concerning the elastic deformation is more approximate to the realitythan the multi-body simulation.(3) The movement characters of valve train have been studied by setting the parametersof rotate speed and the valves clearance. The movement characters of valves train are moreaffected by the valves clearance than that by the rotate speed of diesel. As an emerging computer engineering technology, virtual prototype has a broadapplication prospect. In the research and development of all kinds of complicatedmechanical system, virtual prototype technology will have more and more wide application,and play a more and more important role.