Abstract

The torque fluctuation due to the intermittent combustion pressure and inertia effect of the reciprocating parts generates torsional excitation on the crankshaft of all internal combustion engines. This excitation imposes considerable amount of torsional vibration on the crankshaft. Therefore the torsional vibration modeling and design of an auxiliary absorbing mechanism are very crucial, especially in locomotive diesel engines where the crankshaft is under excitation with high amplitude coupled with large inertia forces due to generators, compressors or fans.

In this research, the capability of centrifugal pendulum vibration absorbers (CPVA) commonly used in rotating machinery to attenuate the torsional vibration in a Locomotive V-type diesel engine crankshaft is investigated. First, an advanced torsional modeling of the locomotive crankshaft has been carried out. This is followed by the development of an accurate excitation torque of a real locomotive engine to the 8th order. The torsional response of the crankshaft under the derived excitation torque has then been investigated.

Finally, the model of the crankshaft incorporating the CPVA (auxiliary system) has been developed and then capability of CPVA to attenuate the torsional vibration of the crankshaft (main system) at resonance frequencies has been investigated. Moreover, the effect of pendulum parameters such as length and mass on the torsional vibration response of the crankshaft in both time and frequency domains has been studied.