New Method for Building Vector of Diagnostic Signs to Classify Technical States of Marine Diesel Engine by Torsional Vibrations on Shaft-Line

Do Duc Luu(Vietnam Maritime University, Hai Phong, Vietnam)
Cao Duc Hanh(Vietnam Maritime University, Hai Phong, Vietnam)
Nguyen Xuan Tru(Naval Technical Institute, Hai Phong, Vietnam)


Vector of diagnostic signs (VDS) using torsional vibration (TV) signal on the main propulsion plant (MPP) is the vector of z maxima (or minima) values of the TV signal in accordance with the cylinder firing orders. The technical states of the marine diesel engine (MDE) include R= z+1 classes and are presented in z-dimensional space coordinate of VDS. The presentation of Dk, k=1÷R using z diagnostic signs (Vi, i=1÷z) is nonfigurative and quite complicated. This paper aims to develop a new method for converting VDS from z-dimensional to 2-dimensional space (two-axes) based on the firing orders of the diesel cylinders, as an equivalent geometrical sign of the all diagnostic signs. The proposed model is useful for presenting a technical state Dk in two-dimensional space (x, y) for better visualization. The paper verifies the simulation of the classification illustration of the 7–state classes for the MDE 6S46-MCC, installed on the motor vessel (MV) 34000DWT, using the new above mentioned method. The seven technical state classes (for 6-cylinder MDE,z=6) are drawn separately and visually in the Descartes. The received results are valuable to improve smart diagnostic system for analyzing normal/misfire states of cylinders in operation regimes.


Two-dimensional vector of diagnostic signs of torsional vibration signal; New model of VDS for misfiring diagnostics of MDE; Vision diagnostics of MDE by torsional vibration signal

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