Research And Simulation Software Development On Balance Characteristic Of Three-cylinder Engine

Reducing the vibration and noise of the engine is a major research topic in the field of automotive engineering.In recent years,in response to the call of the society for energy conservation and emission reduction,and the control of the cost of the vehicle enterprise,the three-cylinder engine has received more and more attention.The speed unevenness of the three-cylinder engine is usually more obvious than other multi-cylinder engines due to the small number of cylinders.Moreover,the vibration and noise of the three-cylinder engine are prominent due to the structural characteristics of the three-cylinder engine and the wrong design and manufacture.In order to improve the NVH performance of the three-cylinder engine,the main work are listed as follows.First of all,the vibration of the engine mainly comes from the inertial force and torque generated by the crank-link mechanism.Due to its structure,the three-cylinder engine has a more prominent vibration problem.This paper analyzes the kinematics and dynamics of the crank-link mechanism,and then analyzes the unbalanced vibration characteristics of the three-cylinder engine.Through calculation and analysis,it is found that the unbalanced force(torque)of the three-cylinder engine is mainly the rotational inertia moment and the reciprocating inertia moment.The balance of rotating inertia moment and the first-order reciprocating inertia moment is achieved by setting counterweight and balance shaft.Secondly,the transmission mode of the balance shaft of the three-cylinder engine also affects the quality of the engine.In this paper,the gear transmission mode is selected by comparing the characteristics of various transmission modes,and the noise mechanism of the gear transmission is analyzed.The virtual prototype model of the three-cylinder engine was built using ADAMS software to study the meshing characteristics of balance shaft transmission system.The stiffness and damping characteristics of the damping gear with rubber bushing were obtained through experiments.The effects of damping gear and rigid gear on gear pair transmission error,balance shaft speed fluctuation,angular acceleration fluctuation and gear pair meshing force are studied under different crankshaft speed fluctuations.It is found that the damping gear can reduce the meshing force by attenuating the transmission error of the gear pair to reduce the vibration and noise of the three-cylinderengine.Finally,in order to facilitate the simulation analysis of the unbalanced vibration characteristics of the three-cylinder engine and the vibration characteristics of the balance shaft transmission system,and the design of the engine balance scheme,and improve the design and development efficiency of the engine,a three-cylinder engine simulation and analysis software was developed by using Matlab and ADAMS.