81 Torsional Frequency Analysis of Multi-Cylinder Inline Diesel Engine Generator System

The main purpose of this paper is to analyze the four stroke multi-cylinder diesel engine coupling generator system for torsional vibration. In this work the modified Holzer method is used for free and forced vibration analysis of mass-elastic system and to determine the natural frequencies of torsional vibration of a multi-cylinder inline diesel engine generator set. The natural frequency of a system is important as it is the main cause of various types of failures. The high level harmonic forcing torque developed in engine can produce large torsional stress levels resulting in early fatigue failure in crankshaft. Therefore by knowing the natural frequencies and frequency modes of the engine the limitations in use of the engine working speeds can be fixed (i.e. for present case 1317.00rpm). From further torsional vibration analysis it is found that the calculated vibratory stresses are well within the allowable stress limit.