Abstract: In order to analysis the torsional vibration changing law of the 4100QBZL diesel engine crankshaft,a finite element model of crankshaft is built in ANSYS.A model analysis is carried out.On the basis of modal analysis,the crankshaft of the flexible body neutral file is built.The coupled multi-body dynamics model of crankshaft system is established,the motions is cylinder pressure as experiment data under many conditions.After the simulation,the main journal,connecting rod journal load results is got.Then torsional vibration simulation is operated,crankshaft torsional vibration amplitude with the load and speed is obtained.Results show that with the increase of engine speed and load,the torsional vibration of crankshaft are tend to be larger,and speed greater influence on torsional amplitude values,the shafting vibration amplitude under various conditions satisfy engineering demand.The simulated results can be used to improve the NVH of diesel engine in optimum design.

Key words: diesel engine, crankshaft, ADAMS vibration analysis, torsional vibration