Research On Prediction Of Noise Of Hybrid Electric Vehicle Power System

Due to the requirements of various aspects such as energy and environment,the active development of new energy vehicles has become the choice of many large auto companies,and has been strongly supported by national policies.Among them,the hybrid electric vehicle has become the product with the largest development potential among new energy vehicles due to the consideration of energy saving and battery life requirements.The hybrid vehicle power system is mainly composed of an engine and a power coupling mechanism.It is one of the most important parts in a hybrid vehicle.Its vibration and noise characteristics have a greater impact on the performance of the vehicle.This paper takes the power system of a hybrid electric vehicle as the research object,and conducts the vibration and noise research of the power system for its engine and power coupling mechanism.The main work of the thesis is as follows:1.Vibration characteristics analysis of the whole engine.Based on the finite element theory,the finite element model of the engine was established to solve the modal parameters of the whole machine.Using the theory of degrees of freedom reduction,the finite element model of the engine was reduced to build the multi-body dynamics model of the engine.The combustion pressure in the cylinder was used as the load to obtain the engine torque and engine surface vibration speed.2.Dynamic characteristics analysis of the coupling mechanism.Using ADAMS and ANSYS,the rigid-flexible coupling dynamic model of the double-row planetary gear dynamic coupling mechanism was established.The high-speed condition was selected as the simulation condition,and the motor speed and torque obtained from the experiment were used as the load,and the engine torque fluctuation was considered.Through dynamic solution,the characteristics of gear meshing force and bearing restraint force of the coupling mechanism were obtained.3.Vibration response analysis of the coupling mechanism shell.Establish a coupling mechanism shell model,use ANSYS Workbench to perform constrained modal analysis on the coupling mechanism shell based on modal theory,extract the first sixteen natural frequencies and vibration modes of the shell.At the same time,the vibration response of the shell was analyzedwith the bearing restraint force as the excitation,and the vibration displacement of the surface node of the shell was obtained.4.Radiated noise simulation.Based on the acoustic theory and acoustic boundary element method,the prediction models of the engine and the dynamic coupling mechanism shell radiated noise were established respectively.Using the vibration response of the engine and the coupling mechanism shell as boundary conditions,the radiated noise of the main components of the hybrid vehicle power system was calculated,and the field point sound pressure level and sound power level spectrum were obtained.Optimize the shell design of the coupling mechanism and calculate the optimization effect.