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1
EN
The study concerns numerical tests of an internal combustion engine operating according to the over-expanded cycle carried out in the AVL Fire software. The research covered the modelling of a full working cycle of a conventional engine operating in accordance with the classic Otto cycle and an engine operating on the basis of an over-expanded cycle – the Atkinson cycle. As part of the work, three cases of Atkinson’s cycle were analysed, by closing the inlet valve before BDC (21º before BDC) and closing the valve after BDC (41º and 75º after BDC). As a result of modelling, space-time distributions of velocity, pressure and temperature in the cylinder of the modelled engine were obtained. Optimizations of the analysed cycles were carried out, finding the best ignition timing, at which it is possible to obtain the highest efficiency and the highest indicated mean effective pressure. The calculations showed that the engine operating according to the over-expanded cycle in order to obtain the best operating parameters requires earlier ignition timing compared to the conventional engine. In addition, in the engine operating according to the Atkinson cycle, there is a drop in the indicated mean effective pressure and an increase in the indicated thermal efficiency compared to the engine operating by the classical cycle.
EN
Paper presents results of experimental investigation of combustion process of diesel-gasoline blend in compression ignition direct injection engine. The researches were conducted for constant load of engine at constant rotational speed. Operating parameters of engine powered with diesel-gasoline blend were at the same level as for engine powered by pure diesel fuel. The preliminary study was conducted using CFD modelling. Based on encouraging modelling results preliminary experimental research was carried out. It turned out that it is possible to co-burning diesel with the gasoline as a blend. A mixture of 20, 40 and 60% of gasoline with diesel was used. It was concluded that an increase in gasoline fraction in blend causes delay of start of the combustion process. The homogeneity of the fuel-air mixture was improved due to longer ignition delay, which is accompanied by higher values of pressure rise rate. With 20 and 40% of gasoline fraction causes higher peak pressure compared to reference fuel-burning ware obtained. Up to 40% of gasoline fraction, the BSFC was kept at the same level as for reference fuel. It was observed that with the increase in gasoline fraction up to 40% NOx emission increased as well. Based on the carried out tests it can be stated that it is possible to co-burn gasoline with diesel in a compression ignition engine while maintaining the invariable engine operating parameters and exhaust emissions.
3
EN
The main goal of this research was to analyze the heat release in a compression ignition (CI) engine. Work contains description of the combustion process in the combustion chamber of CI engine with an explanation of the combustion stages. The research was conducted for wide range of load. At full load of engine achieved the highest value of pressure rise, temperature, fuel consumption and indicated mean effective pressure. The lowest values of these parameters were obtained for the smallest load. The full load of engine was characterized by the highest value of the heat release, and the longest combustion period due to the large share of diffusion combustion phase. The lowest load was characterized by 3.5 times less in value of heat release than in case of maximum load and heat release rate course was without visible diffusion combustion phase.
PL
Głównym celem badań było przeprowadzenie analizy wydzielania ciepła w silniku o zapłonie samoczynnym. Badana jednostka to sześciocylindrowy silnik z zapłonem samoczynnym o mocy 80 kW, poddany obciążeniom w szerokim zakresie. Dla obciążenia maksymalnego uzyskano największy przyrost ciśnienia, temperatury, godzinowego zużycia paliwa oraz ciśnienia indykowanego. Najmniejsze wartości powyższych parametrów zostały uzyskane dla najmniejszego obciążenia. Obciążenie maksymalne charakteryzuje się najwyższą ilością wydzielonego ciepła, a także najdłuższym procesem spalania za sprawą dużego udziału spalania dyfuzyjnego. Przy obciążeniu minimalnym wydzielania ciepła było 3,5- krotnie mniej niż dla maksymalnego, ponadto proces spalania trwał najkrócej, bez widocznego udziału spalania dyfuzyjnego.
EN
This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD - AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions.
EN
The results of CFD modelling a dual fuel diesel engine powered with both methanol and diesel fuel is presented in the paper. Modelling was performed with 20 and a 50% energetic share of methanol in the entire dose. The analysis was conducted on both the thermodynamic parameters and exhaust toxicity of dual fuel engine. It was found that the various share of methanol influences the ignition delay of the combustion process and after start of main phase of combustion, the process occurs faster than in case of the diesel engine. It was found that the time of 10-90% burn of the fuel is much shorter than it is in the diesel engine. The dual fuel engine was characterized by higher indicated mean pressure in the whole range of diesel fuel injection timings. While analysing toxic exhaust emission from the dual fuel engine powered with methanol, it was found that the rate of NO formation was significantly higher than from the diesel engine. The combustion process in the dual fuel engine occurs more rapidly than in the conventional diesel engine, which contributes to form areas with high temperature, and in combination with presence of oxygen from the air and oxygen bonded in the methanol, promotes the NO formation. In the case of the dual fuel engine, it was found that soot emission was reduced. The engine running with diesel injection start at 8.5 deg before TDC, the soot emissions were more than twice lower in the dual fuel engine, while the emission of NO was much higher.
Logistyka
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2014
|
nr 6
10737--10744
EN
Results of modelling of thermal cycle of dual fuel compression ignition (IC) engine are presented. The object of investigation is a three cylinders CI internal combustion engine powered by diesel oil and bioethanol fuel E85. The simulations of the combustion process have provided information on the spatial and time distributions of flame spread within the combustion chamber of the test engine. The numerical analysis results have been juxtaposed with the results of indicating the engine on the test stand. Modeling of the thermal cycle of IC engine in the AVL FIRE was carried out within the study. With the increase in the share of bioethanol E85, it can be seen that the greatest intensification of the combustion process takes place in the final stage of combustion. The increase in the share of E85 fuel, ignition delay increases. On the basis of these cross sections can be seen that a dual fuel engine, the flame front propagates at a higher speed. And the initial phase of the combustion starts in a different location of the combustion chamber than in the classic CI engine.
PL
W pracy przedstawiono wyniki modelowania CFD dwupaliwowego silnika o zapłonie samoczynnym zasilanego olejem napędowym i paliwem bioetanolowym E85. Symulacja komputerowa pozwala na zobrazowanie przestrzennych oraz czasowych rozkładów frontu płomienia rozprzestrzeniającego się w komorze spalania silnika. Wyniki modelowania zestawiono z wynikami badań eksperymentalnych. Modelowanie przeprowadzono w programie AVL Fire. Na podstawie badań modelowych stwierdzono, że wraz ze wzrostem udziału E85 następowała intensyfikacja procesu spalania, szczególnie w końcowej jego fazie. Wzrost udziału E85 powodowało wzrost opóźnienia zapłonu. Na podstawie przekrojów komory spalania stwierdzono, że w silniku dwupaliwowym spalanie inicjowane jest w innym miejscu komory spalania niż jest to w silniku klasycznym o zapłonie samoczynnym.
EN
The results of research conducted on a supercharged spark ignition gaseous engine are exposed in the paper. The engine was modified to work as an engine with the Miller cycle. Modification of the engine, that allowed it to work in the Miller cycle, dealt particularly with the camshaft. This modification allows changing both intake and exhaust timings independently with limitations of ±20 deg. During the research, the engine was fuelled with compressed natural gas or hydrogen optionally. It was for making comparison between selected engine parameters, while the engine was working on two significantly different fuels. Both fuels were delivered to intake manifold close to intake valve through a fuel mixer. During the research, pressure data was collected with various both spark ignition timings and equivalence ratios, and boost pressures. On the basis of obtained data the parameters as follows: indicated mean effective pressure, coefficient of variance from the indicated mean effective pressure, Normalized Mass Fraction Burn and Heat Release Rate were calculated and discussed. As observed optimal ignition, timing is advanced for the engine working on hydrogen or natural gas as fuel with the Miller cycle when compared to the classic Otto cycle applied to this engine. In all tests of the engine with the Miller cycle coefficient of variance from the indicated mean effective pressure indicates good stability of engine work. Finally, the engine working on hydrogen is characterized by shorter combustion period that resulted from higher laminar flame speed compared to the natural gas fuelled engine.
EN
The results of theoretical analysis of a mixture formation process during the compression stroke in a prechamber of the IC (internal combustion) gas engine with the stratified mixtures two-stage combustion system were presented in the paper. The course of excess air-fuel ratio changes in prechamber at ignition time λkz in function of degree of the mixture condensation during the compression stroke φ expressing quotient of a temporary cylinder and prechamber volume and maximal value of the volume were estimated. Research concerning λkz sensitivity on changes of rich combustible mixture composition delivered to the prechamber by the additional fuel supply system λko, mixture composition in cylinder _c and degree of filling a prechamber with the rich combustible mixture ξ were performed. According to numerical calculations it was proved that the real gas engine with the two stage combustion system at equal degree requires exact regulation of the three analysed values.
PL
W pracy przedstawiono wyniki modelowania CFD obiegu cieplnego tłokowego silnika spalinowego o zapłonie samoczynnym. Przedstawiono proces generacji siatki obliczeniowej oraz jej optymalizacji. Scharakteryzowano wykorzystany model spalania. Zaprezentowano wyniki walidacji modelu. Pozytywnie zweryfikowany model został następnie wykorzystany do optymalizacji pracy silnika badawczego. Modelowanie obiegu cieplnego silnika przeprowadzono w programie AVL Fire.
EN
Modeling of thermal cycle of turbocharged compression ignited internal combustion engine is presented. The simulations of the combustion process in the IC engine have provided information on the spatial and time distributions of selected quantities within the combustion chamber of the engine. The numerical analysis results have been juxtaposed with the results of indicating the engine on the test stand. Modeling of the thermal cycle of an auto-ignited IC engine in the AVL Fire was carried out within the study.
EN
Results from tests conducted in several RTD centers lead to conclusion that biogas as a potential fuel for the internal combustion (IC) spark ignited (SI) engine features with its satisfactory combustion predisposition causing smooth engine run without accidental misfiring or knock events. This good predisposition is obtained due to carbon dioxide (CO2) content in the biogas. On the other hand, carbon dioxide as incombustible gas contribute to decrease in the brake power of the biogas fueled engine. To analyze mutual CO2 and CH4 content on biogas burning the combustion parameters as follows: adiabatic combustion temperature, laminar flame speed and ignition delay of biogas with various methane content were determined and presented in the paper. Additionally, these parameters for pure methane were also included in order to make comparison between each other. As computed, ignition delay, which has is strongly correlated with knock resistance, can change several times with temperature increase, but does not change remarkably with increase in methane content. Adiabatic combustion temperature does not also ought to influence on engine performance or increase in engine cooling and exhaust losses due to its insignificant changes. The largest change was observed in laminar flame speed, that can influence on development of the first premixed combustion phase.
PL
Wyniki badań przeprowadzonych w różnych centrach badawczych świadczą o tym, iż biogaz można traktować jako potencjalne paliwo do silników spalinowych o zapłonie iskrowym. Zastosowanie tego paliwa sprawia, że silnik pracuje płynnie bez wypadania zapłonów i spalania stukowego. Dobre predyspozycje biogazu jako paliwa spowodowane są z jednej strony zawartością dwutlenku węgla (CO2). Z drugiej jednak strony dwutlenek węgla jako gaz niepalny przyczynia się do obniżenia mocy silnika zasilanego biogazem. W artykule przedstawiono analizę wzajemnej zależności CO2 i CH4 zawartych w biogazie i ich wpływ na następujące parametry procesu spalania: temperaturę adiabatycznego spalania, szybkość rozprzestrzeniania się płomienia laminarnego oraz opóźnienie zapłonu dla biogazu o zmiennej zawartości metanu. Parametry te porównano z parametrami procesu spalania dla czystego metanu. Zgodnie z obliczeniem, opóźnienie zapłonu, które jest ściśle związane z odpornością na spalanie stukowe, może się zmieniać znacząco wraz ze wzrostem temperatury, ale nie zmienia się w istotny sposób wraz ze wzrostem zawartości metanu. Niewielkie zmiany temperatury adiabatycznego spalania nie powinny również wpływać na parametry pracy silnika oraz na wzrost strat chłodzenia lub strat wylotu. Największe zmiany zaobserwowano w szybkości rozprzestrzeniania się płomienia laminarnego, co może mieć wpływ na rozwój kinetycznej fazy spalania.
EN
The results of modeling of thermal cycle of spark ignition internal combustion engine with exhaust gas recirculation are presented. Results of the impact of EGR on the ignition delay and the combustion duration are presented. The optimization of thermal cycle was carried out in terms of ignition advance angle in order to obtain the possible highest value of efficiency and the least NO emission. The results indicated a significant impact of EGR on the ignition delay and combustion duration.
PL
W pracy przedstawiono wyniki modelowania obiegu cieplnego tłokowego silnika spalinowego z recyrkulacją spalin. Przedstawiono wyniki wpływu EGR na zwłokę zapłonu oraz na długość spalania. Przeprowadzono optymalizację obiegu silnika pod względem kąta wyprzedzenia zapłonu w celu osiągnięcia największej wartości sprawności obiegu przy niskiej emisji NO. Wyniki wykazały znaczny wpływ EGR na opóźnienie zapłonu i na długość spalania.
PL
W pracy przedstawiono wyniki badań eksperymentalnych dotyczących korelacji pomiędzy niepowtarzalnością pracy indykowanej (jednym z głównych parametrów pracy silnika spalinowego), a fluktuacjami prądu elektrycznego wytwarzanego w agregacie prądotwórczym zasilanym LPG. Omówiono stanowisko badawcze, metodykę pomiarów oraz przedstawiono wyniki badań korelacji fluktuacji pracy indykowanej z fluktuacjami natężenia prądu. W przypadku jednocylindrowego agregatu prądotwórczego stwierdzono bardzo wyraźny związek między pracą indykowaną silnika spalinowego, a energią elektryczną obliczoną w przedziale czasowym odpowiednio przesuniętym kątowo względem początku cyklu pracy silnika. Nieco gorsza jest korelacja między amplitudą prądu elektrycznego i pracą indykowaną.
EN
The results of investigation of the correlation between fluctuation of indicated work (one of the main parameters of the work internal combustion engine) and fluctuation of electric current from generating set fueled LPG gas are presents. The test stand, measurement methodology and the results of the correlation between fluctuations of indicated work and current fluctuations are showed. A clear relationship between engine indicated work and an electric energy calculated in time interval angularly shifted regarding the beginning of engine cycle was stated in the case of single-cylinder generating set. A little worse correlation between amplitude of electric current and indicated work was achieved.
EN
The paper presents the results of numerical modeling of the complete thermal cycle of the Andoria 1hc102 test engine. Modeling was carried out in the AVL Fire program. Modeling was used in order to determine the optimal ignition angle of the test IC internal combustion (IC) engine. Model tests were carried out for the spark ignition (SI) engine to operate with excess air ratio equal to λ = 1.2. As a criterion for estimating the quality of engine operation cycle, a value of maximum indicated pressure and indicated efficiency were taken. An additional criterion taken was the so-called knock combustion that limits engine performance. Courses of heat release rate and total heat release as a result were obtained. Modeling results show that the test engine powered by a lean mixture of λ = 1.2, should work with the ignition advance angle equal to 12 deg before top dead centre (BTDC). At this ignition advance angle in the engine knock occurred and the engine reached the indicated pressure and the indicated efficiency and were equal to respectively 0.82 MPa and 34.6%.
EN
Results of modelling of thermal cycle of turbocharged compression ignition IC engine are presented. The object of investigation was a 6CT107 turbocharged auto-ignition internal combustion engine powered by diesel oil, installed on an ANDORIA-MOT 100 kVA/ 80 kW power generating set in a portable version. The performed simulations of the combustion process have provided information on the spatial and time distributions of selected quantities within the combustion chamber of the test engine. The numerical analysis results have been juxtaposed with the results of indicating the engine on the test stand. Modelling of the thermal cycle of an auto-ignition piston engine in the AVL FIRE was carried out within the study. Advanced numerical submodels were used to analysis of combustion process, such as: Extended Coherent Flame Model (ECFM-3Z), turbulence model k-zeta-f, injection submodels with evaporation, collisions, coalescence and other. Intake and exhaust processes were included during modelling. This resulted in a lot of information about the intake, fuel mixing, ignition process and the exhaust process. Results of modelling were compared with results from real engine.
EN
The results of analysis of thermal cycle of the test engine are presented in the paper. The study focused on determining the ignition delay in compression ignition engine. The correlations available in literature, Hardenberg and Hase, Wolfer and Watson and Assanis were used to determine ignition delay. With the increase of the EGR the ignition delay has increased. It turned out that very often it is necessary to determine own ignition delay correlation.
EN
The paper presents the results of investigation conducted by the Institute of Internal Combustion Engines and Control Engineering under the research project R10 019 02 entitled "The internal combustion piston engine combined with the sewage sludge gasification system" sponsored by the Ministry of Science and Higher Education. Legal conditions concerning the storage and utilization of sewage sludge are outlined in the paper. The complete gasification system for power generation is discussed. Several issues concerning the gasification reactor, the gas treatment system, the power generator and the IC engine are described. The results of tests carried out on both the gasification reactor and the engine fueled with the obtained producer gas are also reported.
PL
W referacie przedstawiono wyniki zrealizowanego w latach 2007-2010 w Instytucie Maszyn Tłokowych i Techniki Sterowania Politechniki Częstochowskiej projektu badawczego rozwojowego R10 019 02 nt." Tłokowy silnik spalinowy w instalacji zgazowania osadu ściekowego" sfinansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego w Warszawie. Omówiono uwarunkowania prawne dotyczące składowania i utylizacji osadu ściekowego, omówiono zaprojektowaną i zbudowaną w IMTiTS PCz instalację zgazowania osuszonego osadu ściekowego i oczyszczania gazu generatorowego, agregat prądotwórczy z doładowanym silnikiem tłokowym oraz wyniki badań tej instalacji i doładowanego silnika tłokowego zasilanego pozyskiwanym gazem generatorowym.
EN
The results of numerical analysis the combustion process in turbocharged CI engine 6CT107 are presented in the paper. Engine was installed on the ANDORIA's power generator of l 00 kVA/80 kW The results of modelling the combustion process for different angle setting fuel injection, compared with the results obtained by indicating the real engine. Numerical analysis was performed in two programs, designed for three-dimensional modelling of the thermal cycle the piston internal combustion engine, namely AVL FIRE and the KIVA-3V
PL
W artykule przedstawiono wyniki analizy numerycznej procesu spalania w doładowanym silniku spalinowym 6CT107 o zapłonie samoczynnym, zainstalowanym na agregacie prądotwórczym firmy ANDORIA-MOT o mocy 100 kVA/80 kW Wyniki modelowania procesu spalania dla różnych nastaw kąta wtrysku paliwa porównano z wynikami uzyskanymi podczas indykowania silnika rzeczywistego. Analizę numeryczną wykonano w dwóch programach przeznaczonych do trójwymiarowego modelowania obiegu cieplnego tłokowego silnika spalinowego, a mianowicie AVL FIRE oraz KIVA-3V
EN
The results of modeling of thermal cycle of spark ignition internal combustion engine with exhaust gas recirculation are presented. Results of the impact of EGR on the emission of NO in the exhaust and heat release rate are presented. The optimization of thermal cycle was carried out in terms of ignition advance angle in order to obtain the possible highest value of efficiency and the least NO emission. Optimizing the engine cycle, a compromise between the thermodynamic parameters of cycle and emissions can be reached.
PL
W pracy przedstawiono wyniki modelowania obiegu cieplnego tłokowego silnika spalinowego z recyrkulacją spalin. Przedstawiono wyniki wpływu EGR na emisję NO oraz szybkość wydzielania ciepła. Przeprowadzono optymalizację obiegu silnika pod względem kąta wyprzedzenia zapłonu w celu osiągnięcia możliwie największej wartości sprawności obiegu przy niskiej emisji NO. Optymalizując cykl silnika, uzyskano kompromis między parametrami termodynamicznymi obiegu a osiąganą emisją spalin.
19
Content available remote Analiza numeryczna obiegu cieplnego wieloświecowego silnika ZI
PL
W artykule przedstawiono wyniki trójwymiarowego modelowania procesu spalania w silniku ZI z zapłonem wielopunktowym. Porównano wyniki symulacji dla silnika z jedną, dwoma, trzema i czterema świecami zapłonowymi.
EN
3D modelling of combustion process in multi-spark plug SI engine is presented in the paper. Simulation results of engine with one, two, three and four spark plugs are compared.
EN
The paper presents the results of modelling thermal cycle of internal combustion engine including exhaust gas recirculation. The test engine can not achieve the optimum parameters of work due to occurrence of the knock combustion. The influence of EGR on the limits of the knock occurrence in the engine was studied. It turned out that few percent of exhaust gases in the fresh charge effectively shifts the knock limit to higher ignition advance angles. The values of the limit ignition timing for the test engine was determined in order to avoid combustion knock. Larger share of EGR caused too much slowing the spread of the flame inside the combustion chamber of the test engine. EGR at constant angle of ignition was very effective in limiting the content of NO in the exhaust, but on the other hand it has an adverse effect on the engine parameters. The engine operate with exhaust gas recirculation in order to obtain the possible best parameters the ignition timing should be optimized. However, that with increasing values of the thermodynamic parameters of thermal cycle of engine increased NO content in the exhaust. The paper presents results of modelling thermal cycle of IC engine, including exhaust gas recirculation and knock combustion. The object of researches was the S320ER spark ignition internal combustion engine supplied with petrol. The engine was operated at a constant speed of1000 rpm. Modelling of the thermal cycle of the test SI engine in the FIRE software was carried out.
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