Study On Mechanism Of Automobile Engine Vibration Damping

The traditional passive damping has the advantage of simple structure, reliable operation and low cost. But, it cannot meet the requirements of comfort under complex conditions. The effects of active and semi-active vibration damping are more ideal. However their controllers are complex and they are fragile and high cost. Actuators need to consume a large amount of extra energy. Also need to further improve their performance.Three kinds of stepless variable stiffness mechanism—leveraged-guide mechanism, cam mechanism and the non-circular gears mechanism were proposed.a. Leveraged-guide mechanism. The points of forces of the engine and snubber were placed on the same lever. So, the equivalent dynamic stiffness can be gained to meet the requirements, only need to design institutions to achieve L2 and L1 according to certain dynamic condition. Similarly, the dynamic equivalent damping meeting the requirements also can be gained.b. Cam mechanism. Use of the cam contour surface, transmitting the actual vibration displacement of the engine into the different rise of the puncher, the actual working displacement of the damping and the actual vibration displacement of the engine presents a certain function, which can achieve equivalent linear stiffness and damping.c. Non-circular gears mechanism. Use the characteristics of change transmission ratio of non-circular gear, designing non-circular gear mesh right, the required displacement magnification can be obtained. The required equivalent stiffness and equivalent damping can be obtained also.The equivalent linear stiffness and damping were achieved. Overcoming the shortcomings of not adapt to different use conditions, difficult to obtain good ride comfort and handling stability of the traditional passive vibration isolation. Passive damping technology was used to meet the complex condition of large amplitude, large stiffness and large damping under low frequency and small amplitude when small stiffness, small damping under high frequency.The experimental model was set up based on Non-circular gears for the vibration mechanism. The paper analyzed the engine vibration under self-excitation and external excitation. Two computer simulations for the mathematical models of stepless variable stiffness & damping and changeless stiffness & damping vibration damping mechanisms were tested by MATLAB Simulink software tools. The results of the test revealed that damping effect of stepless variable stiffness & damping institutions were ideal, the damping program was feasible especially for low frequency large amplitude control. Research and simulation came to the conclusion: non-circular gears with the advantages of compact structure, accuracy drive, smooth running, easy to implement dynamic balance and a large range of adjustment ,are the best institutions of the these three programs, as the transmission of shock absorber was feasible and more desirable. As long as the non-circular gear pitch curve accordance with control requirements, damping effect was ideal. Its advantages of low cost and no additional energy consumption were important practical significance.