The analysis of a diagnostic informativeness of gas dynamic parameters in a marine diesel engine turbocharging system through an entropy function

The article presents selected elements of the elaborated diagnostic testing method of marine diesel engine working spaces based on the energetic and spectral-correlation analysis of the course of the pulsating exhaust flow process in the channel powering a turbocharger. The investigations have been worked out within the scope of a realization of the research project No. 0T00B02129 funded by the Committee of Scientific Research. Conducting of an analysis of the diagnostic informativeness among the parameters characterizing the observed gas dynamic processes represented an essential methodological question of the project. A mathematical model, enabling simulations of well-known and recognizable engine working spaces failures as well as an entropy functions, as the measure of uncertainty of the set of identified states of the engine unfitness were applied for such a diagnostic purpose. Having evaluated the diagnostic information three diagnostic parameters were selected in the result of experiments of the numerical simulation. Thus, the adequate parameters of a technical state assessment of the marine diesel engine working spaces were chosen while there was no possibility to work out the cylinder indication (to create cylinder indicator diagrams). The conducted simulating investigations represented an introduction to the experimental investigations (to the diagnostic tests) of DETROIT DIESEL and ZVIEZDA engines that had been put into operation on the Polish Navy warships in recent years.

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Experimental Investigations of Marine Diesel Engine Performance Against Dynamic Back Pressure at Varying Sea-States due to Underwater Exhaust Systems

ASME 2019 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2019-7216 ◽

2019 ◽

Author(s):

Harsh D. Sapra ◽

Jaswinder Singh ◽

Chris Dijkstra ◽

Peter De Vos ◽

Klaas Visser

Keyword(s):

Diesel Engine ◽

Thermal Loading ◽

Geographical Location ◽

Engine Performance ◽

Back Pressure ◽

Experimental Investigations ◽

Pressure Waves ◽

Marine Diesel Engine ◽

Marine Diesel ◽

Exhaust Systems

Abstract Underwater exhaust systems are employed on board ships to allow zero direct emissions to the atmosphere with the possibility of drag reduction via exhaust gas lubrication. However, underwater expulsion of exhaust gases imparts high and dynamic back pressure, which can fluctuate in amplitude and time period as a ship operates in varying sea-states depending on its geographical location and weather conditions. Therefore, this research aims to experimentally investigate the performance of a marine diesel engine against varying amplitudes and time periods of dynamic back pressure at different sea-states due to underwater exhaust systems. In this study, a turbocharged, marine diesel engine was tested at different loads along the propeller curve against dynamic back pressure waves produced by controlling an electronic butterfly valve placed in the exhaust line after the turbine outlet. Engine performance was investigated against single and multiple back pressure waves of varying amplitudes and wave periods based on real sea-state conditions and wave data. We found that the adverse effects of dynamic back pressure on engine performance were less severe than those found against static back pressure. Governor control and turbocharger dynamics play an important role in keeping the fuel penalty and thermal loading low against dynamic back pressure. Therefore, a marine engine may be able to handle much higher levels of dynamic back pressures when operating with underwater exhaust systems in higher sea-states.

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Regressive models for condition diagnosing marine diesel engine by torsional vibrations on propulsion shaft-line

International Journal of Modern Physics B ◽

10.1142/s0217979220401268 ◽

2020 ◽

Vol 34 (22n24) ◽

pp. 2040126

Author(s):

Do Duc Luu ◽

Nguyen Tri Minh ◽

Cao Duc Hanh ◽

Nguyen Huy Hao

Keyword(s):

Diesel Engine ◽

Fractional Factorial Design ◽

Vibration Signal ◽

Fractional Factorial ◽

Diagnostic Purpose ◽

Marine Diesel Engine ◽

Shaft Line ◽

Marine Diesel ◽

Diagnostic Signs ◽

Factorial Design Of Experiments

This paper presents results of study in building diagnostic regressive models (RMs) of cylinders in Marine Diesel Engine (MDE) using torsional vibration signal (TVS) on the propulsion shaft-line. For diagnostic purpose, the vectors of diagnostic signs (VDS) were designed and constructed based on the features of the TVS: maxima and minima relatively with [Formula: see text] working cylinders in real-time domain, or amplitudes of [Formula: see text] first harmonics ([Formula: see text] for two-stroke MDE, and [Formula: see text] for four-stroke MDE) in frequency domain. The received RMs are equations showing the relationships between the diagnostic sign [Formula: see text], [Formula: see text] ([Formula: see text] or [Formula: see text]) of the TVS and [Formula: see text] factors [Formula: see text], [Formula: see text] which specify common states of [Formula: see text] DME’s cylinders. The factor [Formula: see text] here was calculated by using firing coefficient Cfi ([Formula: see text] = 2Cfi-1; Cfi = 0 when [Formula: see text]-cylinder is misfired, and Cfi = 1 when [Formula: see text]-cylinder is normally fired) value of each cylinder. The Fractional Factorial Design of experiments (DoE) [Formula: see text] was used to build the mentioned RMs. The MDE on MV.HR.34000 DWT, with [Formula: see text] and [Formula: see text] was observed and analyzed. The calculated linear regressive models were tested based on the [Formula: see text]-distribution standard.

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Physical model of energetic processes in the marine diesel engine

Zeszyty Naukowe Akademii Marynarki Wojennej ◽

10.5604/01.3001.0010.6737 ◽

2017 ◽

pp. 1-1

Author(s):

Artur Bogdanowicz ◽

Tomasz Kniaziewicz ◽

Marcin Zacharewicz

Keyword(s):

Mathematical Model ◽

Energy Efficiency ◽

Diesel Engine ◽

Physical Model ◽

Dynamic Processes ◽

Marine Diesel Engine ◽

Naval Academy ◽

Gas Dynamic ◽

Marine Diesel

The paper describes the preliminary physical model of gas-dynamic processes that take place in the cylinder of marine diesel engine. The model is a part of the work undertaken at the Institute for Construction and Exploitation of Ships at the Polish Naval Academy. The physical model is the basis for the development of a mathematical model of marine diesel engine, which will be useful for determining the energy efficiency of Polish ships, as well as for diagnostic purposes.

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