Study On Vibration And Noise Prediction And Characteristics Of 6S35ME-B9 Low Diesel Engine

With the widely application of the marine diesel engine, the research of low speed diesel engine is being taken more and more seriously,the vibration and noise of the diesel engine has a great influence on diesel performance. In this paper, based on 6S35ME-B9 diesel engine ,as mastering the characteristic of the diesel engine excitation sources, research the vibration and radiated noise character of diesel engine's main components,and then test about the vibration response and radiation noise is done, in order to forecast the character of engine vibration and noise .Based on the existing diesel engine model data, low speed diesel engine's main parts model was established, which includes the frame and the cylinder ,and so on. Meshing software was used to set up diesel engine finite element model and conduct modal analysis,as well as mastering the structural characteristics of diesel engine. When the engine load was 75%?100%, through Multi-body dynamics and the crosshead model on ADAMS software were usedto calculate the cylinder pressure,cylinder head force, main bearing force and crosshead striking force, which aims to preparing for the subsequent analysis of the diesel engine 's vibration response.Then each of the exciting force calculated is loaded into the main finite element model of diesel engine by finite element analysis software. In the time domain analysis, the whole machine vibration response character under the action of two kinds of stress,which include cylinder head pressure, cylinder explosion pressure and main bearing force of the combustion pressure and crosshead striking force were analyzed, then analysis about the diesel engine vibration characteristics under the action of two kinds of exicting force at the same time is implemented. Based on the basis of the whole machine vibration analysis, the diesel radiated sound pressure in various working conditions was caculated,it can be obtained that the main frequency of low diesel engine exicting force is low frequency and the principal vibration character. and then the diesel vibration prediction can be done.When the diesel engine is under 100% load and runing smoothly and steadily,vibration response and the radiated sound pressure test,and the diesel vibration surface distribution and sound pressure distribution of each radiating surface can be obtained. Then some main points were piced up and compared with simulation result.Test result and simulation can be agreed well in feature frequency and providing some guidance for vibration and noise control.