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EN
This article presents topics concerning fire hazards during the use of low-speed diesel engines in marine vehicles. The causes and effects of fires in the spaces of scavenge air receivers in marine diesel engines are presented. Methods to prevent and fight these fires are shown, including the operating procedures required from ship engine room operators. The possibility of training personnel to apply the abovementioned procedures during operation using simulations of a Kongsberg MC-90 IVship engine room is presented. Simulations were conducted which included a fire in a scavenge air receiver occurring during the operation of a MAN B&W 5L90MC main engine, with loads corresponding to 50% and 100% of the machine’s recommended setting.
EN
A cylinder liner and piston ring running under starved lubrication near the top dead centre (TDC) and bottom dead centre (BDC) cause abnormal friction and wear during operation of a marine diesel engine. The method of laser texturing is proposed to improve the surface friction property under this condition. Spherical crown pits with different parameters were formed on the surface of samples by femtosecond laser processing. The BDC and TDC conditions of oil starvation were simulated in a reciprocating friction and wear experiment, and a numerical model of Surface texture lubrication based on the Reynolds equation was established. The influence of the distribution density, diameter, and depth parameters of the texture on the surface properties was studied. In the BDC condition, compared with the untextured surface, the average coefficient of friction (COF) can be reduced by up to 24% and the average friction force can be reduced by up to 18%. In the TDC condition, the COF can be reduced by up to 19%, and the average friction force can be reduced by up to 18%. Therefore, the textures with various parameters should be arranged in different positions on the cylinder liner; more attention should be paid to the optimisation of diameter in the texture of the cylinder liner near the BDC, whereas more attention should be paid to the optimisation of distribution density in the texture of the cylinder liner near the TDC
EN
With the implementation and expansion of international sulfur emission control areas, effectively promoted the marine low sulfur diesel fuel (MLSDF) used in marine diesel engines. In this study, a large low-speed, two-stroke, cross-head, common rail, electronic fuel injection marine diesel engine (B&W 6S35ME-B9) was used for the study. According to diesel engine’s propulsion characteristics, experiments were launched respectively at 25%, 50%, 75%, 100% load working conditions with marine low sulfur diesel fuel to analyze the fuel consumption, combustion characteristics and emissions (NOx, CO2 , CO, HC) characteristics. The results showed that: Marine diesel engine usually took fuel injection after top dead center to ensure their safety control NOx emission. From 25% to 75% load working condition, engine’s combustion timing gradually moved forward and the inflection points of pressure curve after top dead center also followed forward. While it is necessary to control pressure and reduce NOx emission by delaying fuel injection timing at 100% load. Engine’s in-cylinder pressure, temperature, and cumulative heat release were increased with load increasing. Engine’s CO2 and HC emissions were significantly reduced from 25% to 75% load, while they were increased slightly at 100% load. Moreover, the fuel consumption rate had a similar variation and the lowest was only 178 g/kW·h at 75% load of the test engine with MLSDF. HC or CO emissions at four tests’ working conditions were below 1.23 g/kW·h and the maximum difference was 0.2 or 0.4 g/kW·h respectively, which meant that combustion efficiency of the test engine with MLSDF is good. Although the proportion of NOx in exhaust gas increased with engine’s load increasing, but NOx emissions were always between 12.5 and 13.0 g/kW·h, which was less than 14.4 g/kW·h. Thus, the test engine had good emissions performance with MLSDF, which could meet current emission requirements of the International Maritime Organization.
EN
Marine engines are very complex technical objects, having many important functional systems, which include, inter alia, injection system, characterized by high unreliability. In this system, there may be different types of defects (damage) that affect the engine parameters, including specific fuel consumption, as well as failures endanger the safety of the ship. The indicator diagrams and analysis of indicated parameters have limited utility in the diagnosis of damages of marine engine, although this is a method commonly used in operational practice. To achieve greater diagnostic effectiveness, when, based on indicator diagrams, are calculated and then the characteristics of heat release is analysed - net of heat release characteristics and the intensity of the heat release, it was demonstrated. This procedure is particularly effective in the diagnosis of damages of marine diesel engine injection system components. It has been shown that the characteristics of heat release contain information about the condition of the injection systems, which enable to diagnose their failures. This is shown on the example of a clogged nozzle holes (their carbonizations). The obtained results allowed selecting the diagnosis symptoms, useful in detecting these faults in the injection system, from the characteristics of heat release: net heat release (Q) and intensity of heat release (q). The object of the research was typical marine medium speed engine Sulzer A25/30.
EN
The change of some parameters of an engine structure affects emission of harmful components in engine’s exhaust. This applies first of all to damages in a charge exchange system as well as in a fuel system and an engine supercharging system. These changes are significantly greater during dynamic states and in the time transient processes. It is possible to talk about different sensitivities of emission factors understood here as diagnostic parameters for the same extortion from the structure of the engine but executed in other load states. The article presents a diagnostic model of the engine in which the diagnostic symptoms are indicators and characteristics of the emission of gaseous exhaust components. The model was supplemented with the results of tests on the real object, which was a marine diesel engine. Propose measures of the sensitivity of the diagnostic parameter during dynamic processes - processes characterized by high variability of waveforms, which variability causes problems not only of measurement nature, but also often interpretive.
PL
Zmiana niektórych parametrów struktury silnika wpływa na zmianę emisji składników szkodliwych w spalinach. Dotyczy to przede wszystkim uszkodzeń następujących w układzie wymiany ładunku a także w układzie paliwowym i układzie doładowania silnika. Zmiany te są zdecydowanie większe podczas trwania stanów dynamicznych i towarzyszących im procesów przejściowych. Można więc mówić o różnej wrażliwości wskaźników emisji rozumianych tutaj jako parametrów diagnostycznych na te same wymuszenia pochodzące od struktury silnika, ale realizowane w innych stanach obciążenia. W referacie przedstawiono model diagnostyczny silnika, w którym symptomami diagnostycznymi są wskaźniki i charakterystyki emisji gazowych składników spalin. Model uzupełniono wynikami badań na obiekcie rzeczywistym, którym był okrętowy silnik spalinowy. Zaproponowano również miary wrażliwości parametru diagnostycznego podczas procesów dynamicznych - procesów charakteryzujących się dużą zmiennością przebiegów, która to zmienność powoduje problemy nie tylko natury pomiarowej, ale również często interpretacyjnej.
EN
The article presents a mathematical model of a marine propulsion system and a computer program based on the LabVIEW environment. For a purpose of model construction, a ship's hull resistance was identified and an approximation equations of the Wageningen institute for ship propellers were used. The ship's motion equations were used to build the propulsion system model. On the basis of conducted tests of Sulzer 6AL20 / 24 marine engine, a map of concentrations harmful compounds was created in various load state and transferred to a computer program.
EN
The operation of a ship's propulsion system is a variable process in time, which is described in both static and dynamic states. The mutual proportions between them depend primarily on a type of ship and tasks to which it was designed. In a case of special units of particular use (e.g. warships) and ships, which operate on narrow waters such as canals or port basins, participation of dynamic states is increasing significantly. Hence a necessity to analyze the dynamic states of marine diesel engines, among others in terms of their increased harmful compounds emission. The paper presents a methodology of engine dynamic state analysis, emission indicators that can be used to assess the dynamic state of a ship have been proposed. As an example of application, the analysis of harmful compounds emissions during dynamic states while a real cruise of navy ship has been carried out. It has been also proposed to use simple dynamics indicators such as single-base and chain indexes to describe the change in concentrations of harmful compounds in dynamic states.
EN
In the article, the concept of technical diagnostics in relation to marine engines was characterized. The compression ignition piston engine was presented as a diagnostic object. The next part of the article discusses the composition of exhaust gases with particular emphasis on compounds harmful to the environment. The available test methods for exhaust composition are also briefly described by means indication of the engine and exhaust gas analyzer. The reduction of emission of harmful compounds in the exhaust gases is also described in the article. The main part of the article presents the research object, i.e. the marine diesel engine piston and the exhaust gases analyzer, as well as tests carried out. The tests were performed for the engine in working order and inefficient condition in order to compare them with the simulated damages of injection pump and turbocharger. The article was completed conclusions.
EN
One of the main problem influencing the combustion process in the cylinder of the marine engine is an fuel spray phenomena. The parameters describing the shape of the fuel spray are named macro parameters. This article presents the research results of the macrostructure parameters of the fuel spray atomized with the marine engine injector. The research were carried out by optical visualization measurement method of Mie scattering. The diameter of nozzle injector was 0.375 mm and L/D coefficient 8.3. In these research were considered different parameters of injection opening pressures and backpressures in the constant volume chamber. Generally conlusions are: the opening pressure influence on maximum spray tip penetration, spray cone angle and influence on speed of the injected fuel. The increase of backpressure into the constant volume chamber causes the reduction of spray tip penetration and the increase of the spray cone angle.
PL
W niniejszym artykule przedstawiono problematykę wyznaczania stałej czasowej termopary. Wskazano na wagę właściwości dynamicznych termopar podczas eksperymentów. Przedstawiono stanowisko laboratoryjne, na którym przeprowadzono badania, mające na celu wyznaczenie stałych czasowych dwóch rodzajów termopar. Zaprezentowano trzy metody obliczania tego parametru. Określono wartość stałej czasowej, wyznaczonej metodą symulacji numerycznej wymiany ciepła między spoiną termopary a spalinami ją otaczającymi, przy założeniu wolnozmienności procesu, czyli przejścia z jednego stanu ustalonego do drugiego. W kolejnym kroku obliczono ten parametr również dla takiego przejścia, jednak dokonano tego na podstawie rzeczywistej szybkozmiennej temperatury spalin, zarejestrowanej podczas badania na stanowisku laboratoryjnym. Jako trzecią metodę przedstawiono określanie wartości stałej czasowej dla warunków chwilowych, dla szybkozmiennej temperatury rejestrowanej podczas eksperymentu, dla przebiegu pseudo­okresowego w obrębie trwania jednego cyklu roboczego silnika. Dokonano porównania i oceny uzyskanych wyników obliczeń, a co za tym idzie, użyteczności metody wyznaczania stałej czasowej termopar.
EN
The article presents issue of determining the time constant of thermocouple. The importance of dynamic properties of thermocouples during experiments was indicated. This paper presents the laboratory stand where experiments were made to determine the time constants of two types of thermocouples. Three methods of calculating this parameter were presented. The value of the time constant was determined by the numerical simulation of heat transfer between thermocouple’s weld and the surrounding exhaust gases, assuming the slow – changing of the process, namely transition from the steady state to the other. In the next step this parameter was calculated for the same transition but it was based on real and quick – changing temperature of exhaust gases, recorded during the experiment on laboratory stand. As the third method there was shown determining the value of time constant for the temporary conditions, for quick – changing temperature, recorded during the experiment, for the pseudo-periodic process within the duration of the cycle of engine. At the end, a comparison and evaluation of the calculation results was made, and the usefulness of the method of determining the time constant of thermocouples.
PL
Artykuł przedstawia możliwości oceny stanu technicznego okrętowego tłokowego silnika spalinowego z wykorzystaniem do tego celu średniego ciśnienia indykowanego na biegu jałowym. Praca została oparta na szerokim materiale badawczym, zebranym podczas diagnostyki silników na okrętach w latach 1997–2018, w której autor uczestniczył osobiście. W artykule zasygnalizowano problemy związane z tą oceną oraz przedstawiono metodykę badań.
EN
The article presents possibilities of assessment of technical condition of a marine diesel engine using the mean indicated idle pressure. The paper was based on wide research material collected during engine diagnostics operated on naval ships from 1997 to 2018. The author was a member of diagnostic team conducting researches. The article shows problems related to this assessment and presents research methodology.
EN
The paper presents based on literature critical evaluation of commonly known methods for determining the mechanical losses of a piston engine. Their advantages and disadvantages were pointed out also the possibility of their use in a marine propulsion system was assessed.
PL
W artykule przedstawiono krytyczną ocenę powszechnie znanych metod wyznaczania strat mechanicznych silnika tłokowego na podstawie literatury. Wskazano na ich wady i zalety oraz oceniono możliwość ich zastosowania w okrętowym układzie napędowym.
EN
With the rapid development of shipbuilding industry exhaust world is also very harmful one kind of environmental issues, and the ship marine diesel engine exhaust gas is mainly produced, so in recent years it has developed a diesel engine SCR system. SCR system can control emissions of nitrogen oxides in the exhaust of vessel, furthermore air pollution can be reduced. The main goal of article was using fluent software to correct SCR system selection and flue gas flow under different size best deflector arrangement is simulated. Next goal is further optimize the structure of the SCR system.
EN
In the operational diagnostic of marine engines, the analysis of indicator diagrams is important. In addition to analysing changes in the values of indicated parameters, should be aimed to oriented broader analysis, including the determination on the basis of experimental indicator diagram of heat release characteristics during the combustion process. In the diagnostics of piston engines, including marine engines, special interest arouses to use single-zone model based on indicator diagrams as a source of information. There are calculated heat release characteristics: net heat release (Q) and intensity of heat release (q). The article discusses the impact problem the characteristics of heat release calculated based on experimental indicator diagram various errors – the compression ratio error and the pressure error at the beginning of compression. Based on the results of own research we analysed the impact on the characteristics of heat release the compression ratio error and the pressure error at the beginning of compression. The effect of the errors on the course of characteristics q and Q, to the typical marine medium speed engine Sulzer A25/30 and low speed engine Sulzer RTA 76 shown.
EN
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.
PL
W artykule opisano model fizyczny procesów gazodynamicznych zachodzących w cylindrach okrętowego tłokowego silnika spalinowego o zapłonie samoczynnym. Prezentowany model powstał w wyniku prac badawczych prowadzonych w Instytucie Budowy i Eksploatacji Okrętów Akademii Marynarki Wojennej. Stanowi on podstawę do opracowania modelu matematycznego, który znajdzie zastosowanie w badaniach nad efektywnością energetyczną siłowni okrętowej oraz będzie użyteczny w opracowywanych w Instytucie bezinwazyjnych metodach diagnostycznych silników okrętowych.
EN
This article shows the importance of the diagnostic improvement methods of marine engines to boost the economy and safety of operation of marine cargo ships. The need to implement effective diagnostic methods is justified by presenting statistical data of marine diesel engines failure and the cost of their operation. Based on the own research has been proven, for the chosen example, that indicator diagrams and analysis of indicated parameters have limited utility in the diagnosis of damages of marine engine, although this is a method commonly used in operational practice. To achieve greater diagnostic effectiveness, when, based on indicator diagrams, are calculated and then the characteristics of heat release is analyzed - net of heat release characteristics and the intensity of the heat release, it was demonstrated. This procedure is particularly effective in the diagnosis of damage of injection system components marine diesel engine.
EN
Changing some of the parameters of the engine structure affects the emission of harmful components in the exhaust gases. This primarily concerns damage in the cargo exchange system as well as in the fuel system and engine boost system. Changes in emissions of harmful compounds are often ambiguous, depending largely on the parameters that shape the combustion process. An additional problem is that often simple but undesired interactions occur with the interaction of these parameters. It is therefore possible to speak of different diagnostic parameters' sensitivity to the same extractions from the engine structure, but implemented in other load states. In cases where the set of parameters is numerous and the values of these parameters are similar, there is a real problem with their proper classification, often based on the discretion of the researcher. In the paper the authors propose a methodology for classification of acquired diagnostic parameters. In previous papers [4, 5], Hellwig's method of information capacity index was proposed as a measure of diagnostic parameter sensitivity. This method can be used to build a diagnostic parameter ranking that divides the set of diagnostic variables into stimulators, destimulators and nominators. This normalization of the set seems to be helpful in making a diagnostic decision not influenced by the discretion of the researcher. The zero unitary method can also be helpful in creating diagnostic tests.
EN
A proposal of a new method for marine engine indicated power determination, based on direct piston position, instead of crankshaft angular position measurement, was presented. With the aid of bond graph theory, it was proved, that the new method is equivalent to conventional method. To verify hypothesis, that the new method has potential of determined indicated power uncertainty reduction, simulated calculations were carried out. Results of calculations for two marine diesel engines: medium-speed, four stroke and slowspeed two stroke type, at assumption of engine crankshaft constant speed, were compared with results obtained by a conventional method. Data, collected by means of a typical portable, industrial, digital indicator on engines in service, were used for simulation. The uncertainties of engines indicated power determined by means of two methods were analysed. The indicated power uncertainty, achieved for conventional method, was nearly twice higher than for new proposed method. Finally, uncertainty structure was analysed and evaluated for both: new and conventional method of engine indicated power determination.
EN
The process of the atomization and formation of the fuel spray can be described by macro- and microstructure parameters. Knowledge of these parameters may be a key information to conduct further optimization of the combustion process. This paper presents the research results of the microstructure parameters of the diesel oil spray atomized with marine engine injector. A measurement technique, named Laser Induced Fluorescence (LIF) in the combination with Mie scattering was used to determine LIF/Mie ratio across the spray. The fuel was injected into a constant volume vessel. LIF and Mie signals were recorded by two cameras at the same time. Nd:YAG pulsed laser was used to create light sheet for spray illumination. Wavelength of λ = 266 nm was used in this study.
EN
The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.
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