Wyniki wyszukiwania - BazTech

1

The influence of selected gaseous fuels on the combustion process in the Si engine

Flekiewicz M., Kubica G.

Transport Problems

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2017

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T. 12, z. 3

135--146

EN

This paper presents the results of SI engine tests, carried out for different gaseous fuels. The analysis carried out made it possible to define the correlation between fuel composition and engine operating parameters. The tests covered various gaseous mixtures: methane with hydrogen from 5% to 50% by volume and LPG with DME from 5% to 26% by mass. The first group, considered as low-carbon-content fuels can be characterized by low CO2 emissions. Flammability of hydrogen added in those mixtures realizes the function of the combustion process activator. Thus, hydrogen addition improves energy conversion by about 3%. The second group of fuels is constituted by LPG and DME mixtures. DME mixes perfectly with LPG, and differently than other hydrocarbon fuels, consisting of oxygen as well, which makes the stoichiometric mixture less oxygen demanding. In the case of this fuel an improvement in engine volumetric and overall engine efficiency has been noticed compared with LPG. For the 11% DME share in the mixture an improvement of 2% in the efficiency has been noticed. During the tests, standard CNG–LPG feeding systems have been used, which underlines the utility value of the research. The stand-test results have been followed by combustion process simulation including exhaust forming and charge exchange.

2

The possibilities of using DME (BioDME), as an additive to conventional gaseous fuels in SI engine

Flekiewicz M., Kubica G., Marzec P.

Combustion Engines

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2017

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R. 56, nr 4

150--155

EN

The results of SI engine fueled with blends of LPG and DME are presented in the paper. The range studies submitted includes measurements at varying engine loads, at selected values of speed. The research was conducted on a chassis dynamometer, specifying the engine load by the degree of throttle opening. Value of the mass fraction of DME in the blend with LPG was determined based on previous analyzes. The selected fuel blends containing from 7 to 17% DME (mass fraction). During the study was also performed a series of comparative measurements with pure LPG. Analyses show that of DME can be used as a partial substitute for LPG in SI engines. Its presence does not a negative impact on performance and emissions of the engine. The obtained results indicate that the amount of addition of DME should be varied depending on the engine load. Moreover, the use of this fuel does not require changes to the design fueling system and storage of LPG.

3

Badanie elektromechanicznych właściwości wtryskiwacza gazu

Warczek J., Flekiewicz M.

Przegląd Mechaniczny

|

2016

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nr 10

42--45

PL

Wtryskiwacz gazu jest elektrozaworem dozującym paliwo do silnika. Działanie takiego elementu nie różni się znacząco od sposobu działania wtryskiwaczy benzyny, główne różnice konstrukcyjne wynikają z objętości dawkowanego paliwa w danym stanie skupienia. Dla tej samej masy paliwa w stanie ciekłym i gazowym występują znaczne różnice jego objętości. Z tego względu pola przekroju kanałów paliwowych wtryskiwaczy gazowych są znacznie większe. Zwiększone przekroje kanałów wymusiły zwiększenie wymiarów elementów zamykających przepływ gazu, co powoduje zwiększenie sił inercyjnych. Precyzja dawkowania przy jednoczesnym zachowaniu dużej dynamiki ruchu trzpienia wtryskiwacza jest osiągana za pomocą cewek elektromagnesów, wytwarzających odpowiednio duże siły elektromagnetyczne. Stosunkowo duże masy elementów ruchomych są przyczyną wymuszeń dynamicznych, wywołujących drgania w momencie otwierania i zamykania elektrozaworu. Głównym celem przeprowadzonych badań było określenie zależności pomiędzy sygnałami elektrycznymi wtryskiwacza LPG i drganiami mechanicznymi.

EN

The gas injector is a solenoid valve dispensing fuel to the engine. The principle of operation of such an element is not significantly different from the way the petrol injectors. The main structural differences arise dosed volume of fuel in the state of aggregation. For the same mass of fuel in the liquid and gas state there are significant differences in its volume. Therefore, the channel cross-sectional area of fuel gas injectors are much greater. Increased cross-sections increase in size forced closure elements gas flow and also increase the forces of inertia. Precision dosing while maintaining high dynamics that stem injector is achieved by means of magnetic coils, producing sufficiently large electromagnetic forces. The relative large mass of moving parts are the cause of extortion dynamic vibrating when opening and dosing the solenoid valve. The main objective of the study was to determine the relationship between the electrical signals of the injector LPG and mechanical vibrations.

4

Sterowanie wtryskiem paliwa gazowego w układzie "master-slave"

Flekiewicz M., Szymonik M.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2015

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z. 86

13--20

PL

Artykuł poświęcony został samochodowym systemom zasilania gazowego. Zawiera informacje dotyczące czynników konstrukcyjnych, które mają wpływ na poprawę jakości pracy samochodowej instalacji gazowej, oraz rozwoju samochodowych systemów zasilania gazowego. Głównym nurtem artykułu jest określenie sposobu prowadzenia badań, które umożliwiają poprawę jakości powstających instalacji gazowych. W artykule przedstawiona została możliwość realizacji badań nad poprawą jakości systemów gazowych w warunkach laboratoryjnych, czyli pozasamochodowych. W tym celu skonstruowanourządzenie symulujące pracę samochodowej instalacji gazowej oraz reagujące na zmiany poszczególnych parametrów, które mają wpływ na dawkowanie paliwa gazowego. Omówiono w nim istotę działania skonstruowanego urządzenia sterującego procesem wtrysku paliwa gazowego, a także przedstawiono niektóre z jego możliwości przez wykonanie badań stanowiskowych.

EN

Article was devoted to the automobile gas supply systems. Contains information about the structural factors that have an impact on improving the quality of work car gas system, and the development of automotive power systems of gas. The main subject of the work is to determine how to conduct research for improving the quality produced gas installations. The paper presents the possibility of implementing research on improving the quality of the gas system in the laboratory or outside the car. For this purpose a device simulating car gas installation work, and responding to changes in various parameters affecting the gas dosage. It discusses the nature of the action constructed in the control of gas injection process, and presents some of its features by performing stand tests.

5

Current status and prospects for the use of low-carbon gaseous fuels in transport

Flekiewicz M., Kubica G.

Combustion Engines

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2015

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R. 54, nr 1

62--72

EN

The paper presents a detailed analysis of the issues related to an improvement of the efficiency of energy conversion in SI engines, fueled by low-carbon gaseous fuels. The research was conducted on an engine fueled with natural gas (CNG) and methane/hydrogen blends. The applied gaseous fuels are characterized by a reduced share of carbon, which enables a reduction of the emission of CO2. The object of the research was a 1.6 dm3, 4-cylinder engine originally fitted in Opel Astra F. The engine was equipped with a CNG injection system. The final analysis includes the influence of the ignition advance angle and fuel composition on the engine performance and exhaust gas composition.

PL

W artykule przedstawiono szczegółową analizę zagadnień związanych z poprawą efektywności konwersji energii w silniku ZI, zasilanym niskowęglowymi paliwami gazowymi. W przeprowadzonych badaniach stanowiskowych silnik zasilano gazem ziemnym (CNG) oraz mieszaninami metanu z wodorem. Wykorzystane mieszaniny metanowo-wodorowe cechuje obniżony udział węgla, co daje możliwość zmniejszenia emisji CO2 jako produktu spalania. Obiektem badań był 4-cylindrowy silnik o pojemności 1,6 dm3, zamontowany fabrycznie w samochodzie Opel Astra F. Jednostkę napędową wyposażono w alternatywną instalację zasilania wtryskowego CNG. W analizie końcowej określono wpływ składu paliwa gazowego na podstawowe wskaźniki pracy silnika i skład emitowanych spalin.

6

Ocena wpływu mieszaniny DME i LPG na osiągi silnika ZI

Flekiewicz M., Fabiś P.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2013

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z. 81

31--44

PL

Niniejsze opracowanie jest kontynuacją prowadzonego przez autorów programu badań nad aktywatorami spalania alternatywnych paliw gazowych, wykorzystywanych do napędu pojazdów samochodowych. Zaprezentowano w nim wybrane parametry dynamiczne samochodu napędzanego mieszaniną LPG i eteru dwumetylowego, którego udział masowy zawierał się w zakresie od 5 do 26%. Dla każdej z mieszanin określono również zużycie energii oraz sprawność jej przetworzenia w układzie napędowym badanego pojazdu, napędzanego czterocylindrowym silnikiem o pojemności skokowej 1.6 dm³.

EN

This paper present is continuing of research programme about gaseous fuels combustion activators which are used for vehicle feeding. The article presented chosen vehicle dynamic parameters gained by mixing LPG and DME for range of mixture from 5 up to 30%. The vehicle was powered by 1.6 SI engine adapted to gaseus fuels feeding. The work presents results of used energy and it convert efficiency at the driveline system fitted four cylinders SI engine with 1.6 cm³ capacity.

7

The effects of blending dimethyl ether with LPG on the engine operation and its efficiency

Flekiewicz M., Kubica G.

Combustion Engines

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2013

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R. 52, nr 3

86--95

EN

The paper presents a continuation of a research program related to the activators for gaseous fuels used in modern vehicles. Selected vehicle dynamic parameters obtained by the application of a mixture of LPG and DME for the mass share of 0 to 26 % have been presented. The object of the research was a 1.6 SI engine adapted to a combustion of gaseous fuels. The authors present the results of the energy conversion efficiency in a four cylinder SI 1.6 cm3 engine.

PL

Artykuł prezentuje wybrane wyniki badań nad aktywatorami spalania alternatywnych paliw gazowych, wykorzystywanych do napędu pojazdów samochodowych. Określono wpływ udziału DME w mieszaninie DME-LPG na sprawność przetwarzania energii w silniku ZI. Obiektem badań był czterocylindrowy silnik napędzający samochód Opel Astra, wyposażony w dodatkowy układ zasilania, typu PFI. W badaniach wykorzystano mieszaniny DME-LPG o udziale masowym DME od 0 do 26 %. Dla każdej z mieszanin zrealizowano kilka serii pomiarowych, w ustalonych warunkach pracy silnika. Wyjaśniono wpływ udziału DME w mieszaninie na osiągi silnika, a także podstawowe parametry charakteryzujące proces spalania. Stwierdzono, że masowy udział DME nieprzekraczający 11 % wpływa na zwiększenie sprawności przetworzenia energii, przyrost ciśnienia, stopień wypalenia ładunku i ilość wydzielanego ciepła.

8

An influence of methane/hydrogen proportion in fuel blend on efficiency of conversion energy in SI engine

Flekiewicz M., Kubica G.

Journal of KONES

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2012

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Vol. 19, No. 3

117-124

EN

The relations between methane/hydrogen proportions in fuel blend are presented in this paper. The research cycle carried out contains results of dynamometer chassis tests complemented with mathematical model calculations. An object of X16SZR engine installed in Opel Astra I was investigation. The engine has been equipped with additional CNG feeding system where fuel is being injected into intake manifold under low pressure. 8 fuel blends were tested with variable methane/hydrogen volume proportion (%): 100/0, 95/5, 90/10, 85/15, 80/20, 70/30, 60/40 and 50/50. The feeding and ignition systems were controlled by nominal drivers. In every measuring series engine was tested in the following steady states: on idle, high speed without load and full power at discrete variable speed in range 1500…3500 rpm. The main aspect of the analysis was to identify the influence of hydrogen share on engine parameters such power, fuel consumption, in-cylinder pressure, temperature and exhaust gas composition. Very significant ecological fact possibility of CO2 emission reduction has been identified. Result of increasing content of hydrogen in fuel mixture is engine knocking. Analysis carried out on the basis of results allowed it to the point on methane/hydrogen proportion in fuel blend considering a total efficiency, emission and heat flux in parts of combustion chamber in engine.

9

Applying experts methods in the selection procedures of foresight development programs

Markusik S., Cieśla M., Gąska D., Krawiec S, Flekiewicz M., Janecki R.

Logistics and Transport

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2011

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Vol. 12, No. 1

75-82

EN

Foresight method is gaining support around the world as a powerful tool that creates common views on future development strategies. It is characterized by a unique feature, which is the maximum participation of stakeholders and experts. The paper presents examples of the results of research carried out based upon the expert methods of foresight procedures. Special attention was paid to different methods of identification and involvement of experts in implementing the projects. The methodology of foresight projects was brought closer, with particular emphasis on those methods which are based on expert knowledge - such as the Delphi technique, panel discussion, brainstorming, STEEP and SWOT analysis methods, public consultation and the scenarios formulation. The result of foresight exploration based on knowledge of experts is the formation of a wide vision of the future development of economy and technology, which helps to make decisions on an effective, long-term strategy of the government, enterprises and scientific institutions.

10

Wykorzystanie DME do napędu pojazdów samochodowych. Cz. II

Flekiewicz M.

Czysta Energia

|

2011

|

Nr 2

25-27

11

Wykorzystanie DME do napędu pojazdów samochodowych. Cz. I

Flekiewicz M.

Czysta Energia

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2011

|

Nr 1

17-20

12

Combustion temperature and exhaust gas composition in si engine fuelled with gaseous hydrocarbon fuels

Flekiewicz M., Kubica G.

Journal of KONES

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2010

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Vol. 17, No. 3

105-111

EN

This paper presents the issues connected with the process of combustion of natur al gas and methane-hydrogen blend in SI engine. Enriching methane with hydrogen is the way to make the combustion process more efficient and gives possibilities of CO 2 emission reducing. The detailed analysis focused on changes in temperature profile and their impact on thermal charge and composition of the emitted exhaust gas. All the range of investigation is divided into threeparts. First part is dedicated to comparison of combustion temperatures of LPG, CNG and Petrol. In the middle part are presented the results of investigation of influence ignition advance on combustion temperatures of CNG. The third part includes the results of research project aimed at opportunities of efficient combustion of gaseous fuels, whose main constituent is methane. The selected group of fuels included: CNG, and methane-hydrogen blends (with volumetric hydrogen shares - 5%, 10%, 15%, 20% and 30%). The tested engine was an Opel Astra naturally aspirated four-cylinder 1.6 l petrol engine with power output of 55 kW at 5200 rpm and torque of 128 Nm at 2600 rpm. This engine was modified in a way allowing its CNG propulsion without compression ratio variations. The investigations were carried out on chassis dynamometers and were the basis for analysis by means of mathematical simulation model, in this paper. The obtained results were compared to measurements for fuelling with unleaded petrol (95-octane) as a base fuel for this drive unit. Fuelling of engine with blend of methane and hydrogen opens up opportunities for considerable reduction in CO 2. For blend contains 30% of hydrogen the emission of CO 2 was 35% lesser than in petrol case.

13

Ignition timing advance in the bi-fuel engine

Flekiewicz M.

Transport Problems

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2009

|

T. 4, z. 2

117-127

EN

The influence of ignition timing on CNG combustion process has been presented in this paper. A 1.6 liter SI engine has been tested in the special program. For selected engine operating conditions, following data were acquired: in cylinder pressure, crank angle, fuel mass consumption and exhaust gases temperatures. For the timing advance correction varying between 0 to 15 deg crank angle, the internal temperature of combustion chamber, as well as the charge combustion ratio and ratio of heat release has been estimated. With the help of the mathematical model, emissions of NO, CO and CO ₂ were additionally estimated. Obtained results made it possible to compare the influence of ignition timing advance on natural gas combustion in the SI engine. The engine torque and in-cylinder pressure were used for determination of the optimum engine timing advance.

PL

W artykule przedstawiono wpływ kąta wyprzedzenia zapłonu na przebieg spalania mieszaniny powietrza i gazu ziemnego. Program badań przeprowadzono na stanowisku wyposażonym w silnik ZI, o pojemności skokowej 1.6 dm3. Dla wybranych warunków pracy silnika rejestrowano między innymi takie parametry jak: ciśnienie wewnątrz cylindra, położenie wału korbowego, zużycie paliwa. Korygując kąt wyprzedzenia zapłonu w zakresie od 0 do 15 stopni w stosunku do nastaw ustalonych przez producenta dla paliwa benzynowego wyznaczono stopień wypalenia ładunku, temperaturę ładunku oraz współczynnik wydzielania ciepła. Za pomocą modelu matematycznego opisującego proces spalania wyznaczono również stężenia produktów spalania, tj.: NO, CO i CO ₂. Uzyskane wyniki umożliwiły porównanie wpływu kąta wyprzedzenia zapłonu na przebieg spalania gazu ziemnego w silniku ZI. Na podstawie analizy położenia maksymalnej wartości ciśnienia oraz maksymalnej wartości momentu obrotowego wyznaczono najkorzystniejsze dla gazu ziemnego wartości zmian kąta wyprzedzenia.

14

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.

15

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.

16

Uwarunkowania prawne adaptacji pojazdów samochodowych do zasilania paliwem gazowym

Flekiewicz M.

Nafta-Gaz

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2009

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R. 65, nr 8

609--616

PL

Ujednolicenie wymagań w zakresie bezpieczeństwa eksploatacji pojazdów zasilanych paliwami gazowymi jest jednym z istotnych działań podejmowanych przez Europejską Komisję Gospodarczą ONZ. Niezależnie od działań ogólnoświatowych, władze ustawodawcze wielu krajów wprowadzają w życie wymagania prawne obowiązujące na ich obszarze administracyjnym. W naszym kraju okres ostatniego dwudziestolecia to czas zwiększonego zainteresowania systemami zasilania paliwami gazowymi; tak wśród producentów pojazdów, jak i ich indywidualnych użytkowników. Stale rosnąca liczba pojazdów zasilanych paliwami gazowymi wymaga prawnego uporządkowania całego obszaru działań związanych z procesem przystosowywania pojazdów do zasilania takim rodzajem paliwa, dopuszczaniem ich do ruchu na drogach publicznych i okresową kontrolą ich stanu technicznego. W niniejszym artykule omówiono regulacje prawne przyjęte do stosowania w Polsce, dotyczące wykorzystania paliw gazowych do napędu pojazdów samochodowych. Scharakteryzowano również badania homologacyjne, systemy kontroli zgodności, oraz omówiono elementy systemu kontroli prawidłowego przebiegu montażu instalacji zasilającej. Wykazano również, że wybrane elementy systemu powinny być objęte stałą kontrolą, prowadzoną przez upoważnioną jednostkę techniczną. Odpowiednio nadzorowany system zgodności zapewnia bowiem zarówno racjonalne wykorzystanie energii zawartej w paliwie gazowym, niski poziom emisji składników toksycznych pojazdów, jak i bezpieczeństwo eksploatacji.

EN

The unification of regulations regarding safety of vehicles alternatively powered with gaseous fuels is one of the most important challenges undertaken by UN EEC. Independently from the world tendencies, many countries have already introduced their own regulations. Last twenty years, definitely may be considered as a period of significant increase of gaseous fuels popularity in Europe, both by car manufacturers as well as individual customers – the aftermarket. Increasing all the time number of alternatively gas powered vehicles makes it necessary to arrange form the legal point of view – the entire area regarding the vehicle transformation procedures, their technical approval for circulation, and finally their regular maintenance. Detailed analysis of LPG and CNG containers equipment design has been presented and discussed in this paper. A special attention has been paid to their fire – safety features, especially ones responsible for elimination of tank explosion danger in the vehicles under fire. Homologation procedures has been also briefly described and it has been proved that certain components of LPG/CNG retrofit system have to be regularly controlled by the certified company, what does guarantee the safety of system during its operation.

17

The identification of piston-cylinder clearance using time-frequency methods

Flekiewicz M., Fabiś P., Madej H.

Journal of KONES

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2009

|

Vol. 16, No. 4

93-103

EN

A fault recognition technique for the internal combustion engines using time-frequency representations of vibration signal has been 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 ofhigher engine elements wearing. In this paper an application of acceleration signals for the estimation of the influence of piston skirt clearance on diesel engine block vibrations has been described. Engine body accelerations registered for three simulated cases representing piston skirt clearance variations were an object of preliminary analysis. The presented procedures were applied to vibration and pressure signals acquired for a 0.5 dm3 Ruggerini, air cooled diesel engine. reciprocating machines are difficult to diagnose using traditional frequency domain techniques due to the fact they generale transient vibrations. In the experiments that were conducted Gabor Analysis and Adaptive Spectrogram has been chosen The Gabor spectrogram is a powerful tool for on-line monitoring and diagnosis of combustion process. There are important features of the vibration signal that are sensitive to the change of IC engine condition. For that reason the DWT transform was applied. Based on the results, authors propose detection and piston skirt clearance monitoring algorithm.

18

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.

19

Analysis of operating conditions and emissions of the selected components of exhaust gas during SI engine braking phase

Ubysz A., Łazarz B., Flekiewicz M.

Journal of KONES

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2009

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Vol. 16, No. 4

469-476

EN

This paper presents analysis of conditions of CO2, CO, HC and NOX emissions during engine braking phase invehicles with 1.6 SI engine, based on the results of investigations by Professor Romaniszyn. The analysis aimed to determine the effect of cooling of catalytic converter and engine chamber on emissions of toxins and fuel efficiency in next driving phase. Based on own investigations, the synthesis of fuel consumption under three non-driving conditions of engine operation (i.e. continuous drive, engine braking and drive in neutral) is also presented. Current research centres often carry out extensive investigations of fuel efficiency and emissions of toxic compounds during real use of vehicles. Their results, due to previous assumptions or limitations in the scope of investigations, rarely provide an overall view of the problem. These attempts are typically made in scientific papers and dissertations [1-3]. Selective approach to the problem can be justified by the complexity and varied impact of each phase of engine 's operation on fuel consumption under unsteady heat conditions. Fuel consumption map in speed-acceleration coordinates for vehicle and engine, characteristics of CH emissions, parameters of engine braking phase and temperature characteristics of exhaust gases before catalytic converter are presented in the paper.

20

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.