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1
Content available On board recognition of different fuels in SI engines with the use of dimensional and non-dimensional vibration signal parameters
Fabiś P., Flekiewicz B., Flekiewicz M.
Silniki Spalinowe
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2009
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R. 48, nr 1
69-75
EN
Gaseous fuels such as natural gas and propane butane mixtures are currently the most popular fuels for dual fuel internal combustion engines. Gaseous fuels are more resistant to knocking than conventional liquid fuels they mix better with air. There have been many published works on the use of gaseous fuels but the problem of the combustion noise, as a very important source of acoustic discomfort is not getting enough attention. Combustion noise occurs in a direct and indirect form. It is transmitted throughout the engine block as a vibration at a different spectrum of frequencies. In this study an attempt has been made to correlate the combustion noise with the operating parameters of an engine fueled with LPG, CNG and CNG-hydrogen mixtures as compared to petrol fueled engine. Signals of multiple resonance in the combustion chamber and corresponding vibration signals of the cylinder block of engine have been considered for one combustion cycle. A four cylinder, 1.6 dm3 spark-ignition engine converted to run on LPG, CNG and CNG-hydrogen mixtures has been tested in the project. A well known diagnostic parameter was used for comparison of the engine noise for its operation on gasoline and alternative fuels. A new non-dimensional indicator has also been proposed for the engine vibration estimation purposes the Increase Wavelet Ratio precisely described in the paper.
PL
Paliwa gazowe, takie jak mieszanki propanu butanu czy gaz ziemny są obecnie najpopularniejszymi paliwami zasilającymi silniki spalinowe. Paliwa gazowe znane są z większej odporności na spalanie detonacyjne niż paliwa płynne oraz łatwiejszego wymieszania z powietrzem. Wiele prac poświecono zasilaniu silników paliwami gazowymi, lecz problemu hałasu w trakcie spalania, jako bardzo ważnego źródła dyskomfortu, do tej pory nikt nie rozpatrywał. Hałas procesu spalania można podzielić na wewnętrzny i zewnętrzny. Wewnętrzny hałas jest transmitowany przez ścianki bloku silnika przy różnej częstotliwości. W artykule przedstawiono wyniki analiz sygnału drganiowego ścianki bloku silnika przy zasilaniu różnymi paliwami. Silnik o ZI o pojemności 1,6 dm3 przystosowano do zasilania paliwem LPG, CNG oraz mieszankami CNG i wodoru. Przeprowadzono badania wpływu obciążenia i prędkości obrotowej na poziom drgań bloku silnika. Do oceny wyników badań użyto znanego wskaźnika bezwymiarowego. W artykule zaproponowano także nowy wskaźnik bezwymiarowy do oceny drgań bloku silnika. Jest to przyrost współczynnika falkowego.
2
Content available remote Estimation of IC engine fault using wavelet transform
Fabiś P., Flekiewicz B., Flekiewicz M., Sroka R.
Silniki Spalinowe
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2009
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R. 48, SC2
21--26
EN
A fault diagnosis technique for internal combustion engines using time-frequency representations of vibration signal is presented in this paper. Engine block vibration results as a sum of many excitations, mainly connected with engine speed and their intensity increases with the appearance of a fault or in case of higher engine elements wearing. An application of acceleration signals for the purposes of selected faults detection like piston skirt clearance increase by means of excessive wear, inlet system leaks as well as misfire has been described in this paper. Engine management system adaptive algorithms can mask some faults especially in their early progress. Reciprocating machines are difficult to diagnose using traditional frequency domain techniques because of generated transient vibrations. The Wavelet Transform has been chosen in the case of described project.
PL
W artykule przedstawiono wyniki badań silników ZI metodami wibroakustycznymi. Celem badań było określenie przydatności wybranych metod przetwarzania sygnałów wibroakustycznych do wykrywania błędów, takich jak: luz w układzie tłok-cylinder spowodowanym zużyciem eksploatacyjnym, nieszczelność układu dolotowego oraz wypadanie zapłonów. Badania przeprowadzono na hamowni podwoziowej przy stałej prędkości obrotowej i obciążeniu silnika. Z dotychczasowych badań wynika, że adaptacyjne systemy sterowania silników mogą powodować maskowanie niektórych uszkodzeń, zwłaszcza we wczesnych fazach rozwoju. Dlatego w diagnostyce silników spalinowych poszukuje się nowych metod przetwarzania sygnałów wrażliwych na rozwój uszkodzeń. Z przeprowadzonych badań wynika, analiza falkowa jest skutecznym narzędziem umożliwiającym ocenę stanu technicznego i pracy silnika.
3
Content available New diagnostic methods of alternative LPG/CNG injection systems
Flekiewicz B., Flekiewicz M.
Journal of KONES
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2009
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Vol. 16, No. 2
109-116
EN
Diagnostic methods of gas alternative feeding systems were presented in this paper. Methods of validation for properly cooperation between OEM petrol systems and gas injection system were described. Procedures allowing the analysis ofproper operation of both petrol and alternative feeding systems were presented. A detailed study has been done on seąuential injection system, as a solution fulfilling restricted requirements of new SI engines. Obtaining both satisfactory emission reduction level and minimal power drop for alternative engine gas operating is only possible with all diagnostic procedures especially ones connected with system prototyping phase being done with high precision equipment characterized by low inertia of transducers. Sensors output signals reąuire acquisition with the use of more complex and faster systems. Proper choice of test equipment at each step, guarantees repeatability and what results also reliability ofrealized diagnostic procedures. Influence of alternative gas fuelling systems on mixture adaptation, transfer function, diagnostic methods for prototyping phase, diagnostic procedures for alternatively powered vehicle operation, diagnosis of sequential gas injection system during normal system maintenance are presented in the paper.
4
Content available An attempt of exhaust gases composition prediction in si engines powered by petrol and gaseous fuels
Flekiewicz M., Kubica G., Flekiewicz B.
Journal of KONES
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2009
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Vol. 16, No. 4
105-113
EN
Optimization procedure of the si engines feeding systems requires the application of newer and more sophisticated tools, as an addition to well known but expensive experimental methods. Numerical methods can be considered nowadays as once playing the most important role in the combustion process analysis. Paper describes the application of the dual zone model, allowing the analysis of the combustion process in an SI engine with the possibility of estimating 10 different exhaust gases i.e.: CO2, CO, H2O O2, NO, N2, H2, H, O and OH. The research has been carried on a 1.6 litr es four cylinder SI engine, fed with petrol and alternatively with LPG and CNG. In-cylinder pressure for the 4th cylinder of the tested engine has been acąuired for several engine speeds. registered in-cylinder pressure traces p=p((fi), together with the volume variation nii=nii((fi) infunction ofcrank angle, were used in the combustion process simulating calculations. Obtained results made it possible to compare selected parameters describing the combustion process. Obtained results do also prove recognized fact related to the higher temperature necessary to initiate gaseous fuel combustion.
5
Content available The possibility of the SI engine CO2 emission reduction with the application of CNG-hydrogen blends
Flekiewicz M., Kubica G., Flekiewicz B.
Journal of KONES
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2008
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Vol. 15, No. 3
139-146
EN
The influence of hydrogen-methane blends application in SI engines on their CO2 emission is the main goal of this paper. The 1.6 litre engine alternatively fed with either petrol, CNG and with methane-hydrogen blends has been tested in the research program. The possibility of passenger car engine operation on H2-CH4 mixtures has been demonstrated in the paper, with the underlining of the potential of those mixtures in the increasing of the engine efficiency. Necessary changes in strategy of engine regulation, especially in air/fuel ratio, ignition advance and EGR rate, were noticed and prepared. The methane-hydrogen blends, which were used in the research programme featured ratios as follows: 5%, 10% and 15% of hydrogen. For selected engine operating points, following data has been acquired: in cylinder pressure variation, crank angle, manifold pressure and finally mass fuel consumption. On the basis of registered data for all fuels - burned temperature in cylinder has been estimated, as well as the charge combustion ratio, and the heat release rate. With help of mathematical model describing the exhaust gases formation it has been possible to estimate the NO, CO and CO2 emission level. Obtained results made it possible to compare the combustion process for all tested fuels and pointed on the significant influence of hydrogen percentage for the methane-hydrogen blends, on the CO2 emission reduction up to 20%. Negative aspects of chosen blends application have been also describe in the paper, especially of increasing engine thermal load.
6
Content available Recognition of fuel feeding SI engines with use of dimensional and nondimensional vibration parameters
Flekiewicz M., Fabiś P., Flekiewicz B.
Journal of KONES
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2007
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Vol. 14, No. 3
153-162
EN
The availability of gaseous fuels like natural gas and propane butane mixtures has lead to worldwide popularity of internal combustion engines running dual fuel or alternatively gas powered. They are known as fuels more resistant to knocking than conventional liquid fuels and as ones less pollutant, their better mixing with air is also well recognized. There have been many published works on the use of gaseous fuels but actually the problem of the combustion noise, as a very important source of acoustic discomfort is not receiving attention. Combustion noise occurs in two forms, direct and indirect. It is transmitted throughout the engine block as a vibration at a different spectrum of frequencies. In this study an attempt is made to correlate the combustion noise to the operating parameters for LPG and CNG powered engine as compared to petrol fuelled engine. Combustion pressure and vibration of cylinder block data are measured and presented for engine running on LPG/CNG and compared to the results obtained for engine fed by petrol. Signals of multiple resonances in combustion chamber and corresponding vibration signals of cylinder block of engine were considered for one combustion cycle. A four cylinder, 1.6 dm3 spark-ignition engine converted to run on LPG and CNG was tested in the project. The engine test stand was fully computerized and the cylinder pressure data, acceleration of vibration of engine block, crank angle data was stored on a PC. The influence of engine speed, load on combustion and engine block vibration was examined for all fuels. A few of well know diagnostic parameters were used for comparison of the engine noise for operation on petrol, LPG and CNG.
7
Content available remote Funkcja przejścia w systemach sekwencyjnego fazowanego wtrysku paliwa gazowego
Flekiewicz B., Flekiewicz M.
Czasopismo Techniczne. Mechanika
|
2004
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R. 101, z. 6-M/1
225--232
PL
W artykule przedstawiono rolę funkcji przejścia w systemie sekwencyjnego fazowanego zasilania paliwem gazowym oraz zasadnicze czynniki decydujące o prawidłowości jej konstrukcji.
EN
The role of transfer function in sequential gas injection system, and main factors describing its proper construction has been presented in this paper.
8
Content available remote Zasilanie paliwami gazowymi a systemy OBD - część II
Flekiewicz B.
Zeszyty Naukowe. Transport / Politechnika Śląska
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2003
|
z. 48
143-148
PL
Celem niniejszego opracowania jest określenie wpływu alternatywnego zasilania paliwem gazowym na pracę systemu diagnostyki pokładowej - OBD. Przedstawiono wpływ konstrukcji funkcji przejścia na prawidłowe działanie układów diagnostyki pokładowej - OBD.
EN
Determining the influence of alternative gas fuelling on onboard diagnostic system was the main goal of this study.
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