Simulation Of Diesel Engine Fuel Injection System Vibration And Noise

With the improvement of fuel injection pressure, the vibration and noise of diesel enginefuel injection system is making more significant contribution to the engine vibration andnoise.Grasping the characteristics of the excitation source of fuel injection system is the basicfoundation to improve the design of fuel injection system, further in order to improve dieselpower, reduce emission and lower the effect of noise and vibration which is the pursuit ofmodern diesel engine. The paper studies the vibration of fuel injection system and enginenoise induced by it in detail.Firstly the actual fuel injection system of4102BG is established with AVL model andADAMS model to obtain the fluid excitation and mechanical excitation. Based on the models,structure optimization of the fuel injection system is implemented to reduce the vibrationexcitation source, on the premise of normal injection pressure.Then experimental modal analysis of pump is conducted to verify the accuracy of thefinite element model of fuel injection system and the factors that affect the modal analysisresults are given. Mechanical excitation and fluid excitation are applied to the finite elementmodel using transient analysis to get the vibration caused by both excitations. The resultsshow that injection timing of each cylinder can be well reflected in nodal velocity andacceleration curves, and the vibration of fuel injection pump is comprehensive effect of bothexcitations, while there is a certain balance relationship between cam contact force andbearing force.Finally, the engine vibration caused by fuel injection system is studied and the radiatednoise is analyzed using boundary element method. On the basis of above analysis, structuraloptimization of fuel injection system can reduce noise by2-6dB, which uses different oilvalve and cam profile.