Possibilities of using the free-end of crankshaft in diagnosis of slow speed marine diesel engines (original) (raw)

In this article there are discussed possibilities in diagnosis of large marine diesel engines by utilization the freeend of crankshaft in gaining information about engine load in particular cylinders on the basis of course of crankshaft’s transient rotational speed overlapped by torsional vibration. There is defined and calculated crankshaft’s transfer function for torsional vibration being crankshaft’s response to exciting force caused by crank pin efforts. There is presented methodology of reconstruction of crank pin efforts’ course on the basis of calculated transfer function and measured in any given condition course of crankshaft’s speed. There are indicated that similarities between courses of torsional vibration in time and frequency domain for slow and medium speed marine diesel engines will allow to apply the presented methodology of reconstruction of crank pin efforts’ course in large marine diesel engines.