Optimization Design And Research Of Mounting System For Power Assembly Of Light Passenger Car

Powertrain is one of the most principal noise sources and vibration sources of automobiles,while the mounting system which is composed of several mounting cushions connecting thepowertrain and frame of bus (or automobile body) is the most primary approach to decrease andisolate the transmission of vibration from engine to the automobile body. A reasonable enginemounting system can not only extend the life of engine and other components, but the mostimportant is that it can improve the ride comfort. It is the most effective way to solve the enginevibration．Traditional rubber engine mounting system playing an important part in isolating thevibration from engine possesses advantages of simple construction, low cost, long service life,stable performance, and so on, so it is used widely nowadays. This paper makes a comprehensivestudy of the performance of vibration isolation of a light business bus which is researched anddeveloped independently by a motor corporation. It analyses the working principle of vibrationisolation and addresses in detail the modeling mathematical methods of engine rubber enginemount. Six and twelve degrees of freedom ADAMS dynamical model of powertrain mountingsystem are built after the inertial parameter of the powertrain is measured and the parameter tobuild model of the automobile body is calculated, then the accuracy of the models are verified bythe MATLAB program.In the previous research about the powertrain mounting system，experiment and simulationare separated, and the purpose of the former is only to verify the accuracy of the latter，but rarelyto combine them to study of the performance of vibration isolation of mounting system under theengine idle excitation. This paper presents a practical and effective method to determine engineidle excitation which combines test and theoretical calculation, and then the stiffness of themounting cushions of the ADAMS dynamical model of powertrain mounting system isoptimized from the different objective functions and idle vibration isolation rate of thepowertrain mounting system is simulated, calculated and analysed with this excitation. The bus’sidle vibration isolation rate, the level of the vibration of seats and rearview mirrors are test,whose test result shows the bus possesses a good performance of NVH, besides, the idlesimulation results of powertrain mounting system and test results agree well.