Internal Combustion Engine Crank Shaft Torsional Vibration Of Multi-body Dynamics Analysis

Endlessly emerging of new technology gradually fulfilled low energy-waste and exhaust target in internal-combustion engine research and manufacture industry. At the same time, the strict request was brought forward at structure reliability design, vibration and noise reduction of internal-combustion engine. As one of all the problems, the crankshaft torsional vibration problem was very outstanding. And now NVH (Noise, Vibration and Harshness) has been paid more attention to in distribution market. Pursuing perfect torsional vibration theoretics and seeking methods to solve torsional vibration is emergent. This paper summarized some methods of researching the shafting torsional vibration before. And based on the virtual prototyping(VP) technology, by using multi-body system simulation(MSS) method, combined with finite element analysis(FEA),the torsional vibration of automotive engine crankshaft is analyzed in this paper. This paper, based on ADAMS, involves five aspects: the components VP modeling, the natural frequency analysis, the dynamic characteristic simulation, the validation experiment and the dynamic characteristic simulation when some cylinders don't work. They are listed as follow.1. This paper take one 6-cylinder turbo charger engine as the research object. First this components were modeling and assembling in UG. Then the multi-body dynamics model for the crankshaft assembly including flexible crankshaft is established by importing the three-dimensional models into the ADAMS and creating the modal neutral file.2. Make the natural frequency analysis of the crankshaft assembly, considering the change of the main bearing and the fixing of the vibration damper.3. Make the dynamic characteristic simulation of the crankshaft assembly at different rotate speed.4. Measure the torsional vibration characteristic parameter of the engine and estimate the validity of the model by comparing the results of the test with the results of the simulation.5. Make the dynamic characteristic simulation when some cylinders don't work and choose the better working project when some cylinders don't work.Through the research we can find that the multi-body dynamics model coincides well with the real crankshaft assembly. And the multi-body dynamics model is convenient to simulate different situation of the crankshaft assembly. As a whole, the multi-body dynamics model is very suitable for the research and exploiture of the engine.