Study on Torsional Stiffness of Engine Crankshaft

Many empirical formulae are used to calculate torsional stiffness of Engine Crank, but discrepancy exists between these calculation results. In this paper, in order to obtain a more precise result, the modified Ker Wilson formula and Carter formula were employed to calculate torsional stiffness of engine crankthrow in the case of different thickness and width of both sides of crankthrows. Furthermore, the finite element models of crank and free part of crankshaft linked to torsional dynamic models are developed, and then the intrinsic torsional vibration frequency of crank and free part of crankshaft are carried out by finite element method. According to the relationship between torsional vibration frequency and torsional stiffness, torsional stiffness of crank and free part of Crankshaft is figured out.