Interior Sound Quality Refinement Base on Mechanism Study of Crankshaft Impact noise 2019-01-0772
A rumbling noise is audible in a vehicle passenger compartment during acceleration. Mechanism Details of the rumbling noise is studied. A series of transfer path testing investigation on chassis dynamometer shows that the interior rumbling noise is mainly induced by abnormal crankshaft impact at particular crank angle. Spectrum analysis also indicates that high level half order harmonic content significantly affects the rumbling noise. Multi-body dynamics model of the powertrain was developed to further investigating the root cause of the abnormal crankshaft impact. Experimental data was used to validate the theoretical model. Sensitivities analysis of various bearing seat structure, crankshaft parameters, engine flange stiffness and cylinder gas pressures were carried out. High deviation of main bearing forces of bearings No.l, 4 and 5 from crank angle 0 to 90 degrees after No.l cylinder's TDC (Top Dead Center) is considered to fundamentally cause the high level half order harmonic content. The ladder frame, a stiff crankshaft and shorten the front end offset of the crankshaft can significantly reduce the abnormal crankshaft impact and improve interior sound quality.
Zhangming Su, Hanshuang Chen, Qi Yang, Dandan Kong, Weizhe Xing, Yanghui Xu, Xuelu Cao
GAC Automotive Engineering Institute, South China University of Technology