Study Optimization Of Vibration Isolation Rate For Automobile Engine Powertrain Mounting System

Engine is one of the main excitation sources of vehicle vibration, therefore, the research on engine powertrain mounting system vibration isolation rate optimization has great significance to improve the car comfort. In design, when the basic data of powertrain and body frame structure has been determined, by adjusting the mounting element’stiffness of powertrain mounting system, installation site, installation angle and damping etc., make each order natural mode of vibration of the powertrain mounting system to achieve reasonable allocation, reduce the delivery from powertrain to frame vibration as far as possible and improve the vibration isolation rate of the system.This paper takes school bus as the object of study, first of all, expounding the research progress of powertrain mounting system’s correlation technique; secondly, evaluating the inertial parameters of the engine’s powertrain which measuring by three wire twist method, rationality simply,establishing the equivalent finite element model of the powertrain mounting system and analysis the modal and decoupling; again, analysis engine excitation force; then, setting up the finite element model of body frame according to the data provided by enterprise and carrying out the free modal analysis for it; finally, establishing the composite pattern which is made up by engine powertrain mounting system, body frame and simplified model of equivalent axle, applying load, analysis the vibration isolation rate, and carry out the automatic optimization of vibration isolation rate for system, the value of integrated vibration isolation rate from-0.33dB to17.9dB after optimization.Combined with practice closely, this paper has good theory and application value.