Sustainable Marine Structures

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

DOI: https://doi.org/10.36956/sms.v2i2.330

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Abstract

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.

Keywords: 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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References

[1] Do Duc Luu: Dynamics and diagnostics of marine diesel engine by vibration technique. Publisher “Transport”, Ha Noi (2009).

[2] Do Duc Luu, et all (2020): Regressive models for condition diagnosing marine diesel engine by torsional vibrations on propulsion shaft-line. International Journal of Modern Physis B. ISSN 02179849. (5 pages). © World Scientific Publishing Company. DOI: https://doi.org/10.1142/S0217979220401268.

[3] Do Duc Luu and Cao Duc Hanh (2021). Automatic Calculation of Torsional Vibrations on Marine Propulsion Plant Using Marine Two-Stroke Diesel Engine: Algorithms and Software. Journal of The Institution of Engineers (India): Series C. ISSN 2250-0545 Volume 102 Number 1. pp. 51-58. https://doi.org/10.1007/s40032-020-00626-y.

[4] Do Duc Luu, Cao Duc Hanh, et al. (2021): Smart diagnostics for marine diesel engines using torsional vibrations signals on the ship propulsion shaft – line. Naval Engineer Journal. ISSN: 0028- 1425. March 2021| No 133-1. pp. 143-153 https://www.ingentaconnect.com/contentone/asne/nej/2021/00000133/00000001/art00026.

[5] Luong Cong Nho, Do Duc Luu, et al.: Researching, building simulation of main propulsion plant and main switch-board on the marine cargo ship. National Independent Project on Science and Technology with ID. DTDL.CN-14/15 carried out in Vietnam Maritime University, Hai Phong (2015 -2019).

[6] Hudong heavy machinery Co. Ltd: Torsional Vibration Calculation Report DE 6S46MC–C7860 kW @ 129 r/min 34,000 DWT. PhaRung Shipyard. DNV Approved 2007.

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