Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 122

Liczba wyników na stronie
first rewind previous Strona / 7 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  silnik okrętowy
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 7 next fast forward last
EN
The article discusses methods for determining top dead center, based on the analysis of pressure diagrams of a marine engine. The advantages and disadvantages of different methods are shown. Diagnostics of marine engines during operation and the selection of optimal operating conditions is based on the analysis of gas pressure diagrams, as well as fuel supply and gas distribution diagrams. As a result of the analysis of the pressure diagrams, the indicator engine power is calculated, which is further used in the management of engine operation modes, in the calculation of specific indicators, as well as in the calculation of energy efficiency coefficients of marine vessels according to International Maritime Organization recommendations. The influence of the accuracy of determining the position of the top dead center on the calculation of the mean indicated pressure and indicator power is shown. The authors considered a method for determining top dead center, based on the solution of the equation P’= 0, which provides the required accuracy in calculating the mean indicated pressure and indicator power of the engine during operation. It is shown that the method can be applicable in marine engine working process monitoring systems as an alternative to hardware methods for determining the top dead center.
PL
W artykule przedstawiono metodę, która pozwala w przybliżony sposób wyznaczyć względną moc okrętowego silnika głównego w warunkach eksploatacji na podstawie standardowego pomiaru ciśnienia powietrza doładowującego w kanale dolotowym. Metoda oparta jest na określaniu współczynników aproksymującej funkcji liniowej, przy znanym ciśnieniu doładowania oraz rodzaju i mocy nominalnej silnika. Jest ona uzupełnieniem innych metod pośredniego wyznaczania mocy efektywnej silnika głównego, wymienionych we wstępie niniejszego artykułu.
EN
The SOx emissions of the marine engine are regulated by international maritime conventions. In this paper, the effect of various parameters, including SO2 partial pressure, liquid to gas ratio (L/G), alkalinity and pH, was investigated by seawater scrubbing experiment in a turbulent contact absorber (TCA) and a spray absorber (SA) on a laboratory scale. The experimental data showed that the desulfurization efficiency of TCA was mainly dependent on the value of L/G and irrelevant to the changing way of L/G; the appropriate L/G of TCA was 2.3 dm3/m3 and pH of effluent water was 2.4–2.8 at the L/G of 1.1–2.8 dm3/m3. Comparatively, the desulfurization efficiency of increasing liquid flow rate was better than that of decreasing gas flow rate in the SA experiment. At the gas velocity of 1.58 m/s and L/G of 2.3 dm3/m3, the desulfurization efficiencies and drop pressures of TCA and SA were 75.9% and 42.4%, 690 and 260 Pa, respectively. The results indicate that TCA chosen as an absorber is likely to be a competitive desulfurization technique for controlling marine diesel emission.
EN
The paper presents a results of vibration tests of common rail injectors operating in diesel engines. The most common methods of diagnosing common rail injectors (CR) as well as the most common damage of injectors of this type have been described. The results and analyzes of tests obtained during measurements on two different test stands were presented. Obtained results allowed for the preliminary determination of diagnostically sensitive parameters, which may allow the development of the injector diagnostics method without the need to stopping the engine.
PL
W artykule przedstawiono wyniki badań drganiowych wtryskiwaczy Common Rail pracujących w silnikach o zapłonie samoczynnym zasilanych. Opisano najpowszechniej stosowane metody diagnozowania wtryskiwaczy Common Rail (CR), jak również najczęstsze uszkodzenia wtryskiwaczy tego typu. Zaprezentowano wyniki i analizy badań uzyskane podczas pomiarów na dwóch różnych stanowiskach testowych. Uzyskane wyniki pozwoliły na wstępne określenie parametrów wrażliwych diagnostycznie, co może pozwolić na opracowanie metody diagnostyki wtryskiwaczy bez potrzeby zatrzymywania silnika.
EN
The measurement of combustion pressure relies on connecting a pressure sensor to a four-stroke marine engine cylinder by a channel led out from the engine cylinder. The geometry of the channel distorts the results of combustion pressure measurements. The purpose of the work is to create a model of combustion processes in engine cylinders. The model uses a mathematical description of the indicator channel on one of the engine cylinders. The input data to the model and the data necessary for its verification came from the direct measurements on the research facility. The test object was a four-stroke Sulzer 3AL25/30 engine loaded by an electric power generator. During calculations, different diameters and lengths of measurement channel were simulated. The obtained results allowed to formulate the conclusion that the geometry of the measurement channel has a significant impact on the measurement results. The increase of the length of the measuring channel as well as the diameter of the channel causes disturbances in the measurement of the maximum pressure.
EN
The lubricating oils are a liquid substance, consisting of a base (mineral, synthetic or vegetable) and selected additives. They can used for lubricate internal combustion engines, so they called – engine oils. For proper functioning of the engine, lubricating oil have to fulfil basic requirements: the main function is to enable the formation of a film of oil between the moving parts which reduces friction and wear, assisting in cooling, keeping the compression ratio, reducing corrosion, filling in all micro ridges on the surface of cooperating components, sealing the combustion chamber etc. The most significant property of any lubricating oil is viscosity, which is the measure of its resistance to gradual deformation by shear stress or tensile stress. The important feature is that property of viscosity changes during the exploitation process of oil, it may increase and decrease. That is why, for engines it is important not only to choose the type of oil correctly but also to frequent monitor the viscosity. In the article, the author shows how the viscosity of marine engine oils changes after working in different types of engines. The experiments were conducted using the method of the rheometer Haake Mars III of Thermo Scientific. The samples of engine oil – Marinol RG 1240 were collected after various periods of use in three different engine types Cegielski- Sulzer.
EN
The paper presents experimental research on a 4-stroke, 3-cylinder, turbocharged AL25/30 Diesel engine. Research consisted in investigating the effect of the geometry of the fuel injectors on the exhaust gas composition from the engine. During measurements, the engine was operated with a regulator characteristic of a load range from 40 kW to 280 kW, made by electric water resistance. The engine was mechanically coupled to the electric power generator. Three observations were made for each engine load, operating with fuel injectors of varying geometry. All considered types of injectors were installed on all engine cylinders. Mentioned injectors differed in the size of the nozzle holes diameters, holes numbers and angles measured between the holes axis. Engine performance data were recorded with a sampling time of 1 s. Cylinder pressure and fuel injection pressure on the front of each injector were collected also. The composition of the exhaust gas was measured using an electrochemical analyzer. According to the results, the change of fuel nozzle geometry results in a change in fuel spraying and evaporation and consequently changes in the course of the combustion process. The effect of this is the change of the composition of the exhaust gas.
EN
In recent years, diagnostics of marine reciprocating engines devote more and more attention. In principle, all methods for the diagnostics of marine engines can be divided into based on the measurement of work parameters (mostly changes in internal cylinder pressure), and measuring the residual energy. For this study the authors focused on the measurement of vibration parameters and their analyzes. Acceleration of vibration measurements was carried out on the engine head. During the tests, fatigues to the injection installation were simulated, it had affected to the value and the course of the gas pressure inside the cylinders. The results of research proving the usefulness of the proposed method.
PL
W ostatnich latach zagadnieniu diagnostyki okrętowych tłokowych silników spalinowych poświęca się coraz więcej uwagi. Zasadniczo wszystkie metody diagnostyczne dotyczące tych urządzeń można podzielić na bazujące na pomiarach procesów roboczych (głownie zmian ciśnienia wewnątrz cylindrowego) oraz na pomiarowych procesów resztkowych. W przypadku niniejszego opracowania autorzy skupili się na pomiarach parametrów drganiowych i ich analizie. Pomiary przyspieszeń drgań realizowano na głowicy silników. W trakcie badań symulowano uszkodzenie aparatury paliwowej mające wpływ na wartość oraz przebieg ciśnienia wewnątrz cylindrowego. Przedstawiono wyniki badań dowodzące użyteczności przyjętej metody.
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
The paper presents an analysis of the influence of the fuel spray geometry on the combustion and emission characteristic of the marine 4-stroke Diesel engine. Presented analysis was prepared based on computational fluid dynamic model (CFD). Initial and boundary conditions of the model as well as data used to model validation were collected during the laboratory study. Calculations were conducted for two different fuel injectors with changed nozzle holes diameters, the number of nozzle holes and the angle between holes axis. The increase of the fuel nozzle holes diameter causes the decrease of the fuel spray tip penetration, but simultaneously the decrease of holes number causes that auto-ignition delay is not changed. The increase of the angle between holes axis from 150° to 158° causes fuel ingintion near cylinder head wall. Result of this is the increase of CO fraction. The deterioration of fuel combustion causes the decrease of NOx mass fraction in the cylinder also.
EN
The article presents the stages of fuel injection modeling of the four-stroke marine diesel engines as a set of functional blocks the of the fuel waves flow. The elaborated model includes the values of changing pressures in the combustion chamber and the course of changes of the pressure in spaces of the injection pump, injection pipe and the injector. Linear and local losses, as well as the conditions for the functioning were taken into account in stages of the fuel flow. The influence of different values of the engine load on the pressure course of the in individual spaces of injection apparatus and in the engine cylinder during the working cycle depending on the crank angle of rotation of the crankshaft have been simulated. The mathematical relationships were selected and the structural and experimental data are used, allowing the calculation of the parameters of interest for the simulated process.
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
In the paper a comprehensive model of a piston ring pack motion on an oil film has been presented. The local thickness of the oil film can be compared to height of the combined surface roughness of a cylinder liner and piston rings. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been combined and used in this paper. In addition a model of gas flow through the labyrinth seal of piston rings has been developed. The main parts of the model and software have been experimentally verified abroad by the author at the marine engine designing centre. For the selected two-stroke marine engine, the influence of the number of piston rings used and the type of the top ring lock (straight or overlapped) on blowby to piston underside and on friction losses of the piston-ring-cylinder (PRC) system have been investigated. The developed model and software can be useful for optimization of the PRC system design.
PL
W artykule przedstawiono rozwój napędów zarówno w transporcie lądowym, jak i morskim, począwszy od pierwszych napędów parowych, motorowych i skończywszy na najmniej rozpowszechnionym napędzie atomowym. Następnie opisano rozwój silników spalinowych w kontekście coraz surowszych przepisów dotyczących dopuszczalnych wartości emisji szkodliwych związków do atmosfery. W kolejnej części artykułu zaprezentowano coraz bardziej zaostrzane przepisy dotyczące emisji związków toksycznych przez silniki okrętowe, ze szczególnym uwzględnieniem Obszarów Emisji Kontroli. Kolejna część artykułu przedstawia stosowane paliwa, zarówno ropopochodne, jak i alternatywne, z których największy rozwój dotyczy paliw odnawialnych. W ostatniej części artykułu omówiono napędy alternatywne, z których najbardziej rozwinięte są napędy elektryczne i hybrydowe. Poza tym uwagę zwrócono nad innymi napędami, nad którymi trwają prace nad ich rozwojem i zastosowaniem w lądowych i morskich środkach transportu. Należą do nich ogniwa paliwowe, panele słoneczne, a nawet niewielkie turbiny wiatrowe. Artykuł zakończono wnioskami, z których najważniejszy jest ten, że coraz trudniej będzie spełnić surowe wymagania stawiane silnikom spalinowym dotyczące emisji szkodliwych substancji, w związku z tym, powszechne wprowadzenie paliw i napędów alternatywnych, będą jedyną szansą na rozwiązanie tego problemu.
EN
The article presents the development of drives, both in land and sea transport, from the first drive of steam, motor and ending with the least widespread nuclear-powered. Then, the development of internal combustion engines in the context of increasingly stringent regulations concerning emission limit values of harmful substances into the atmosphere was presented. Another part of the article presents the used fuel, both petroleum and alternative, with the largest development concerns renewable fuels. In the last part of the article discusses alternative drives, the most developed are electric drives and hybrid. The article was completed conclusions, of which the most important is the only chance to solve the problem of air pollution by combustion engines is the use of alternative fuels.
PL
W artykule omówione zostały sposoby określenia obciążenia cieplnego i mechanicznego silnika okrętowego pracującego w normalnych warunkach oraz z wybranymi niesprawnościami. Badanie polegało na pomiarze parametrów pracy silnika z symulowaną uszkodzoną turbosprężarką oraz symulowaną nieszczelną pompą wtryskową i porównanie ich do parametrów pracy silnika technicznie sprawnego. Badania zostały przeprowadzone w warunkach laboratoryjnych na silniku SULZER 3AL25/30.
EN
The article explains how to determine the thermal and mechanical loads on the marine engine working with normal operating conditions and with selected technical failures. The survey has been based on comparison between the parameters of the engine operating with simulated damaged turbocharger and leaking simulated injection pump, and the engine working in a proper technical condition. The research has been conducted SULZER 3AL25/30 engine, under laboratory conditions
EN
This paper presents the application of modern methods to reproduce a model of selected features of the complex geometric components of present medium-speed marine diesel engines. Geometrical data was obtained in experimental investigations of new objects operating in natural conditions, where measurements of some structural features are very difficult and burdened with great uncertainty. To obtain data for modelling, the analyses of two-dimensional images were used. The aim was to study the geometrical features of the main elements of fuel injection equipment to develop relationships between diagnostic signals to determine the technical state. Such examinations are also useful for the evaluation of the wear and damages of elements when operating in extremely difficult conditions. As a result of geometric measurements, it was possible to get a set of points and to produce digital images of objects.
PL
W pracy ukazano zastosowanie nowoczesnych metod do odtworzenia modelu wybranych cech geometrycznego złożonych elementów konstrukcyjnych współczesnych średnio-obrotowych okrętowych silników spalinowych. Dane geometryczne pozyskano w badaniach eksperymentalnych obiektów nowych i eksploatowanych w naturalnych warunkach, których pomiary niektórych cech konstrukcyjnych są bardzo trudne lub obarczone dużą niepewnością. Do pozyskania danych do modelowania wykorzystano również analizę obrazów dwuwymiarowych. Celem było ukazanie cech geometrycznych głównych elementów aparatury wtryskowej do opracowania relacji sygnał diagnostyczny - stan techniczny w diagnostyce. Badania takie również są przydatne do oceny zużycia i uszkodzeń obiektów pracujących w wyjątkowo trudnych warunkach eksploatacji. W wyniku pomiarów geometrycznych możliwe było pozyskanie zbioru punktów i na ich podstawie opracowanie obszarów cyfrowych obiektów. Stosując program do modelowania w przestrzeni trójwymiarowej możliwe jest odwzorowanie badanych elementów.
EN
The paper presents an analysis of the influence of the fuel injector nozzle holes diameter on parameters of the brake-up, evaporation and combustion process in the cylinder of the marine 4-stroke Diesel engine. Presented analysis was prepared in the basis on computational fluid dynamic model. Initial and boundary conditions of the model as well as data used to model validation were collected during the laboratory study. Calculations were conducted for nominal fuel holes diameter equals 0.375mm and diameters increased and decreased by 50μm and 100μm respectively. According to presented results the increase of the diameter of fuel nozzle holes causes the increase of fuel Sauter’s mean diameter in the initial stage of the injection process and the decrease of fuel process evaporation. The result of this phenomenon is the slowdown of the initial stage of the combustion process and the decrease of both pressure and temperature of combustion.
EN
The article presents an analysis of the use of gas turbine engine in the propulsion and marine power plant of vessels, taking into account environmental aspects. The preliminary results of emission tests of harmful exhaust emissions of the laboratory gas turbine engine were presented. Also an analysis was also undertaken on the possibility of carrying out measurements of concentrations of pollutants in the marine gas turbine engine propulsion systems in terms of its operation on the vessel.
EN
The paper presents the case study of use the artificial neural network to predict the main propulsion marine engine load. Mentioned load of the engine is important parameter to assess the emission level of toxic compounds into the atmosphere according to ISO standard and MARPOL convention. The engine load depends on the ship speed, rotational speed of the engine, propeller blades settings, the direction and the speed of wind, the condition of sea and the direction and the speed of sea currents and construction parameters of the ship. The realization of the aim of the work requires the direct measurement of presented parameters and measurement of exhaust gas composition. The experiment was carried out onboard STS “Pogoria”. Obtained results are enough to use the ANN to predict engine load to measure the emission level of toxic compounds.
EN
The article presents results of a laboratory study on exhaust gas emission level from a marine diesel engine. The object of the laboratory study was a four-stroke marine diesel engine type Al 25/30 Sulzer, operated at a constant speed. The examination on the engine was carried out according to regulations of the Annex VI to MARPOL 73/78 Convention. The laboratory study consisted of 3 observations: the engine assumed to be operating without malfunctions, delay of the fuel injection by 5° of crankshaft angle in the second engine cylinder, and the leakage of the fuel pump on the second engine cylinder. Additionally, parameters of fuel consumption and thermodynamic parameters of the marine engine were measured during the research. Simulated malfunctions caused changes in total weighed NOx, CO, and CO2 emissions for all considered engine loads. All simulated malfunctions caused a small change in measured thermodynamic parameters of the engine. The engine operation with the delayed fuel injection and the fuel leakage in the fuel pump in one cylinder caused a decrease of NOx and CO emission level. Fuel leakage in the fuel pump causes the CO2 emission to decrease only at low engine load. Calculations of the weighed specific fuel consumption present a 1-2% change in the engine efficiency.
first rewind previous Strona / 7 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.