Torsional Vibration

Abstract

The construction of an internal-combustion engine is such as to make it susceptible to resonant torsional oscillation of the crankshaft.

When an engine is operated near a critical speed, that is, a speed at which the pulsations produced by each cylinder excite the natural frequency of the crankshaft, excessive torsional amplitudes are developed which may seriously damage the engine. Unless measures are taken to introduce damping into the system the engine cannot be run continuously in critical speed zones. Restriction of running speeds is generally inconvenient and vibration dampers have to be applied to limit torsional vibration amplitudes and stresses to safe values.