| Mechanical noise is one of the important sources of diesel engine. The 4102BG diesel engine is selected as the research object in this paper. The mechanical noise caused by valve train is studied in detail.Based on the elastic distortion of structure, the mathematical models of the valve train of 4102BG diesel engine are established. And the differential equations about the motion of the valve train are also given. Since the cam is discontinuous, the equation is solved differently in different range. With the mathematical model and theory, the dynamical calculation of the valve train is analyzed. With TYCON, the simulation model of valve train is built. The moving characteristics of every component and the impact force of valve are gained. The two models are proved to be correct by comparing the calculation results of two models,In order to study the vibration characteristic of cylinder head after that it has endured the impact force of valve, the 3D model of cylinder head is built by PROE. After predigested, the finite model is built and its modal is analyzed by ANSYS. The vibration current of the cylinder head is calculated. The transient analysis of the cylinder head is finished with APDL by ANSYS. With the transient analysis result being as the boundary condition, the radiant noise of cylinder head is dealt by the infinite element method by SYSNOISE. In order to validate the academic result, a test rig is erected. The motion of valve train is measured as well as the mechanical noise.At last, the mechanical noise of valve train of TBD620 diesel engine is predicted with the same method. |
