Experiments and Analysis of Crankshaft Three-Dimensional Vibrations and Bending Stresses in a V-Type Ten-Cylinder Engine: Influence of Crankshaft Gyroscopic Motions

Torsional dampers have been attached to engine crankshafts only for the control of the crankshaft torsional vibrations. However, a torsional damper is a mass-spring system of three-dimensions, so the torsional damper could exert some influence on the three-dimensional vibrations of the crankshaft system. Since the inertia ring of the torsional damper has moments of inertia and it rotates with the crankshaft, gyroscopic vibrations of the inertia ring can also be generated.

For a V-type ten-cylinder diesel engine (V- 10, ϕ119 × 150), the three-dimensional vibrations of the crankshaft system were calculated by the dynamic stiffness matrix method, taking account of the influence of the gyroscopic vibrations of the inertia ring of the torsional damper. The dynamic bending stresses were measured at the fillets of both the No.1 crank journal and the No.1 crank pin in the No.1 crank throw plane.

From the comparison of the experimental and calculated results, we investigated the influence of the three-dimensional mass-spring system of the torsional damper and the influence of gyroscopic vibrations of the torsional damper inertia ring on the bending stresses of the crankshaft.