Prediction Technique for Vibration of Power-Plant with Elastic Crankshaft System

The vibrations of an engine crankshaft system under firing conditions are investigated using the dynamic stiffness matrix method in the frequency domain in order to know the displacements of the crankshaft journals. Then the excitation forces on cylinder block are calculated by use of both the displacements and model of bearing oil film. After that, the forces are applied to the finite element model of the power-plant and the accelerations of vibration are obtained. This method was applied to a four cylinder in-line diesel engine (bore : 95.4 mm, stroke : 104.9 mm). The predicted results showed good agreement with the experimental results. Furthermore, simulation time and work could be reduced remarkably.