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1

Research of combustion system with semi-open combustion chamber in a commercial spark ignition engine

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2016

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Vol. 23, No. 4

283--290

EN

During the research of a new combustion system with semi-open combustion chamber for SI engines with use of the rapid compression machine (RCM) and visualisation experimental engine (VEE) it was proved that the application of this system results in shortening of the combustion time, increasing of the maximum cycle pressure and, in effect, increase of the combustion efficiency. The aim of the research using a commercial spark ignition engine was to prove that the similar results (as in RCM and VEE) could be obtained in a wide range of automotive engine operating parameters. In this research the two cylinder, four-stroke air-cooled SI engine, with volume displacement 650 cm³ from Fiat 126 motorcar was used. This engine was fitted with a modified cylinder head and ignition distributor. Two types of prechamber with different shape were installed in different locations into the cylinder head but the ignition distributor had fixed, preadjusted, ignition advance angle in the full range of engine speed. The wide-open throttle characteristics including power, specific fuel consumption and exhaust emission versus engine speed and load characteristics including: specific fuel consumption and exhaust emission versus engine torque were determined for different ignition advance angles. In the lower range of the ignition advance angle the engine showed stable operation at lower speed but unstable at high speed and, inversely, if the ignition advance angle was high the engine operation was stable at the higher speed and unstable at the lower. The engine characteristics during unstable operation were deteriorating. The research results show that improvement of the engine characteristics can be obtained in the full range of operating parameters if the ignition advance angle is varied continuously with the variation of engine speed. The ignition advance angle for the engine fitted with the new combustion system, which was subject of this research, was different form the ignition advance angle for standard engine.

2

Influence of compression ratio on combustion, turbulence, swirls into model combustion chamber of SI engines

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2015

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Vol. 22, No. 4

179--186

EN

The results of the visualization researches, with the pressure measurement results are presented in the paper. Researches deal with the combustion system with semi-open combustion chamber for spark ignition engines. This system was elaborated in Aircraft Engine Department of Heat Engineering Institute of Warsaw University of Technology. During researches the influence of CR on a flame front propagation and turbulences into combustion chamber, when CR and ignition advance are varied, was determined. The model combustion chamber was made with the constant volumes ratio (the prechamber volume to the prechamber plus main combustion chamber volumes) of 28%. The CR were varied: 6:1, 8:1, 10:1 and 12:1, by changing of combustion chamber length and establish high. The researches were performed using rapid compression machine (RCM). The combustion sequences were recorded using high-speed digital camera with speed of 5000 frames per second. Simultaneously with combustion sequences recording, the high-speed pressure courses were registered. The research results show that the growth of compression ratio causes an improvement of combustion system performances; an increase of maximum cycle pressure and useful work field. The improvement of the performances is caused mainly by shortening of the combustion time and intensification of the turbulences and approaching of supposed combustion course.

3

Research effects of novel combustion system with semi-open combustion chamber using rapid compression machine

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2014

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Vol. 21, No. 4

297--310

EN

The combustion system with semi open combustion chamber (SOCC) was originally elaborated in Aircraft Engine Department of Warsaw University of Technology. In this system the original combustion chamber of the standard SI engine, was divided by partition in prechamber and main combustion chamber, but yet this division exists only when the piston is close to TDC, on the contrary by the rest of the cycle the chambers are fully open. The system operation mechanism, the visualization research results, the high speed changed of the pressure measurements, was presented in this paper. The influence on the system performances of the different combustion systems parameters: the prechamber volume, the nozzle hole diameter in the partition, the ignition place, the compression ratio, and the ignition advance angle (IAA), on the basis of the research results, using rapid compression machine was presented in this paper. All research results show, that the best results of the system operation can be obtained if the stream outflow from prechamber to main combustion chamber starts when the piston is at TDC, and if the stream energy will be so big to displace all main combustion chamber before the clearance between partition and piston crown was opened. If the system operated correctly, the combustion time shortening, the growth of the maximum cycle pressure, and the combustion efficiency increase were obtained.

4

Flame front propagation in combustion system with semi - open combustion chamber with different compression ratio

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2013

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Vol. 20, No. 4

227--235

EN

Researches of the combustion system with semi-open combustion chamber for spark ignition engines. This system was elaborated in Aircraft Engine Department of Heat Engineering Institute of Warsaw University of Technology. The researches concern the determination of influence CR on a flame front propagation into combustion chamber when CR and ignition advance are varied. The model combustion chamber make up with the constant volumes ratio of the prechamber volume to the prechamber plus main combustion chamber volumes, of 28%, but the CR were varied: 6:1, 8:1, 10:1 and 12:1, by changing of combustion chamber length. The researches were performed using rapid compression machine (RCM). The combustion sequences were recorded using high-speed digital camera with speed of 5000 frames per second. Simultaneously with combustion sequences recording, the high-speed pressure measurements were performed. The results of the visualization researches, with the pressure measurement results are presented in the paper. The research results show that the growth of compression ratio caused an improvement of combustion system performances; an increase of maximum cycle pressure and useful work field. The improvement of the performances is caused mainly by shortening of the combustion chamber length and approaching of supposed combustion course.

5

Combustion process visualisation in rapid compression machine modelling combustion in spark ignition engines

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2013

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Vol. 20, No. 4

219--226

EN

Mixture preparation and combustion processes in internal combustion engines are very complex and very difficult to investigate. These processes run very quickly and their parameters are changed quickly and in wide ranges. Therefore, the interpretation of measurement results is very difficult and uncertain. The visualization methods applied in the combustion researches can help to interpret the results. For many years, the visualization methods have been developed at the Aircraft Engine Department of Heat Engineering Institute of Warsaw University of Technology, in the field of combustion in engines, detonation and gas dynamics research. In these researches, different method of registration of very fast changes of combustion were applied. The combustion experiments have been performed in constant volume bomb, rapid compression machines and experimental visualisation engines. In the last case, the electronic digital camera of Photram SA 1.3 has been used. This paper refers to the experiments, which were conducted using rapid compression machine. Their goal was explanation the combustion mechanism in combustion system with semi-open combustion chamber under different parameters of this system. The obtained results show a strong influence of combustion system parameters on combustion mechanism, especially on a compression ratio and ignition timing. The strong swirls were registered at all sharp edges on combustion chamber during compression stroke. These swirls had a strong influence on the combustion system operation.

6

Combustion process control in system with semi-open combustion chamber for spark ignition engines

Leżański T., Sęczyk J., Wolański P.

Combustion Engines

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2013

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R. 52, nr 3

434--441

EN

A few operation examples of combustion system with semi open combustion chamber for spark ignitron engines has been presented in this paper. This system has been designed in Aircraft Engine Department of Heat Engineering Institute of Warsaw University of Technology. The principal problem of operation this system is to assure that jet-stream commences to outflow from prechamber to main combustion chamber when the piston is at TDC and that it will have a sufficient energy quickly to displace all main chamber. This is a task for combustion control system. This can be obtained by correct selection of the system operating parameters: the volume ratio of prechamber to total combustion chamber, the hole diameter in partition, the igniter locations, the ignition advance angle. If this system has operate correctly it was obtained the shortening of combustion time about 2.2 time, growth of maximum cycle pressure 1.9 time and increase of combustion efficiency 1.4 time, in comparison to standard combustion chamber. This research results concern the test conducted using rapid compression machine.

PL

W artykule przedstawiono kilka przykładów pracy systemu z półotwartą komora spalania przeznaczonego dla silników o zapłonie iskrowym. System ten został opracowany w Zakładzie Silników Lotniczych Instytutu Techniki Cieplnej Politechniki Warszawskiej. Podstawowym problemem pracy tego systemu jest zapewnienie, że początek wypływu strumienia z komory wstępnej do zasadniczej nastąpi wówczas, kiedy tłok znajduje się w GMP i że energia strugi będzie wystarczająca, aby szybko przebyć całą komorę zasadniczą. Takie jest zadanie układu sterowania. Może to być osiągnięte przez właściwy dobór parametrów pracy systemu: proporcji objętości komory wstępnej do całej objętości komory spalania, średnicy otworu w przegrodzie, miejsca zapłonu oraz kąta wyprzedzenia zapłonu. Jeśli ten system działał prawidłowo, to uzyskiwano: skrócenie czasu spalania około 2.2 razy, zwiększenie ciśnienia maksymalnego cyklu 1,9 razy i wzrost sprawności spalania 1,4 razy, w porównaniu ze standardową komorą spalania. Wyniki te dotyczą badań, które były prowadzone z zastosowaniem maszyny pojedynczego sprężu.

7

Design of the rapid compression machines for combustion researches in spark ignition engines

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2012

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Vol. 19, No. 4

379-391

EN

The rapid compression machines (RCM) are extensive applied to combustion process researches and mixture process preparation research in the internal combustion engines (ICE). The principal advantage of these arrangements is easy optical access to the inside space of combustion chamber. This enables to observe the course of ignition process and the flame propagation process. There are some RCM designs, which they differ, first of all, the modelling method of piston movement into cylinder. The most known designs use the pneumatic and hydraulic drives. Their concern is that they enable the modelling compression stroke only but combustion is performed in constant volume combustion chamber. It was not relevant for the research of the new combustion system elaborated at Aircraft Engine Department of Warsaw University of Technology (AED). The RCM elaborated at AED has unique form it includes the crank mechanism, speedy operating electromagnetic clutch and flywheel. The applying of this design enables modelling the compression stroke and working stroke (two-stroke from engine cycle). It enables assessment of the system with semi-open combustion chamber what it will be impossible using other RCM designs. The different designs RCM used for combustion research at the research and development centres, on worldwide will be compared with the design of RCM developed at AED. The most known designs of the different RCM were described and the research result examples were given in this paper. The advantages and disadvantages of the different designs were discussed too in this paper.

8

Control strategy combustion of system with semi – open combustion chamber of spark ignition engines

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2012

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Vol. 19, No. 4

367-377

EN

The attempts to increase the engine combustion efficiency of the spark ignition (SI) engines have led to development of the new combustion system with semi-open combustion chamber. This system is similar to flame jet ignition systems, which were applied in many production internal combustion engines. The similar pulsed jet combustion system was elaborated by Professor A. K. Oppenheim. In the system developed at Aircraft Engine Department of Warsaw University of Technology (AED) the standard combustion chamber of SI engine was divided on prechamber and main combustion chamber using partition. The ignition in prechamber is more reliable and repeatable but total burning time in the prechamber and main combustion chamber is shorter than in standard combustion chamber. The principal problem of efficient operation of this system and obtaining of the required performance is securing the relevant control strategy. The performances of this system are dependent from: the rate of this prechamber volume to total combustion chamber volume, the orifice diameter in a partition, the ignition place and the ignition advance angle (ignition timing). Among these parameters the ignition timing only may be varied in the continuous manner during the engine operations without of the engine disassembling. Therefore constant values separate parameters (prechamber volume, orifice diameter, ignition place) should be selected in comprehensive, time consuming researches for different engine operation conditions (engine speed, load and environment conditions) and subsequently the map of ignition advance angles should be determined at state remaining separate parameters. The values of the ignition advance angle should be selected and programmed in electronic control unit, which will be control the ignition advance angle at different engine operating conditions. The dependences between engine operating parameters and the ignition timing are not linear and therefore mechanical control system is not effective. Some research results concerning the best engine operating parameters has been presented in this paper.

9

Efekty zastosowania nowego systemu spalania w produkcyjnym silniku tłokowym o zapłonie iskrowym

Leżański T., Sęczyk J., Wolański P.

Silniki Spalinowe

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2011

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R. 50, nr 3

PL

Wyniki badań przy zastosowaniu maszyny pojedynczego sprężu oraz badawczego silnika wizualizacyjnego, pokazują, że zastosowanie systemu z półotwartą komorą spalania może spowodować: skrócenie czasu spalania w komorze spalania, zwiększenie ciśnienia maksymalnego cyklu oraz zwiększenie sprawności spalania. Celem badań w silniku produkcyjnym było wykazanie, że takie pozytywne efekty można uzyskać również w szerokim zakresie parametrów pracy trakcyjnego silnika spalinowego. Badania prowadzono przy zastosowaniu zmodyfikowanego silnika samochodu Fiat 126p. Określono charakterystyki zewnętrzne i obciążeniowe przy różnych konfiguracjach komory spalania i różnych wartościach kąta wyprzedzenia zapłonu. Uzyskane wyniki pokazują, że dzięki zastosowaniu systemu z półotwartą komorą spalania, o właściwie dobranych parametrach systemu, można uzyskać poprawę osiągów silnika oraz zmniejszenie toksyczności spalin.

EN

The research results of a new combustion system with semi-open combustion chamber for SI engines with use of the rapid compression machine (RCM) and visualisation experimental engine (VEE) shown up that the application of this system could be resulted in shortening of the combustion time, increasing of the maximum cycle pressure and, in effect, higher combustion efficiency. The aim of the research with using a commercial spark ignition engine was to prove that the similar results (as with RCM and VEE) could be obtained at a wide range of automotive engine operating parameters. In this research modified two cylinder, four stroke air cooled SI engine, with volume displacement 650 cm3, from Fiat 126, motorcar was used. This engine was fitted with a modified cylinder heads and ignition distributor. Two types of prechamber with different shape were installed in different locations in the cylinder head but the ignition distributor enabled to keep fixed level, preadjusted, ignition advance angle at the full range of engine speed. The wide open throttle characteristics including: power, specific fuel consumption and exhaust emission versus engine speed and load characteristics including: specific fuel consumption and exhaust emission versus engine torque were determined for different ignition advance angles. The research results show that improvement of the engine characteristics can be obtained in the full range of operating parameters if the ignition advance angle is varied continuously with the variation of engine speed.

10

Research of flame propagation in combustion system with semi-open combustion chamber for gasoline SI engines

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2011

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Vol. 18, No. 2

251-260

EN

Some results of visualization researches of combustion system with divided, semi - open combustion chamber for SI engines, using rapid compression machine (RPM) and experimental visualization engine (EVE) are presented in his paper. Short description of combustion system operation, description of test stands and research equipment can be found in the paper. The tests were performed at stoichiometric ratio natural gas-air and propane-air mixtures. A few the most characteristic of results are shown; to explain how should be operate the combustion system, to yield the better performance. They are compared the research results (photographs of combustion sequence, diagrams of in-cylinder pressure histories) during visualization testing with using RCM and EVE. During RCM testing we obtained the combustion photographs in the plain pass in cylinder axis but during ECE testing at the plain perpendicular to the cylinder axis. All researches shown that the best performance are yielded when a spark advance angle (ignition timing) is such selected that stream outflow prechamber to main combustion chamber starts when the piston is at TDC and it has adequate energy to travel a main combustion chamber with higher velocity than burning velocity in quiescent chamber. Then the shortest time of combustion, the highest peak pressure in the cycle and bigger useful working are yielded. The impact of spark advance angle on flame propagation process into combustion chamber in extreme cases has been analyzed too.

11

Some problems of combustion system operation with semi-open combustion chamber for spark ignition engine

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2010

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Vol. 17, No. 4

287-294

EN

The some problems concern of the new combustion system operation with semi open combustion chamber, which can be used in spark ignitions internal combustion engines are presented in this paper. These considerations are based on the visualization research results, with using rapid compression machine (RCM). In this researched combustion system the original combustion chamber was divided by partition in prechamber and main combustion chamber. This division of the original combustion chamber exists only when the piston is close to TDC, for the rest of the cycle the chambers arefully open. Ignition is initiated in the prechamber using electric spark plug, but the mixture in main combustion chamber is ignited by the stream of the burned gases injected from prechamber through the orifice in partition, if the ignition advance angle is correct. If the ignition advance angle is incorrect the mixture from prechamber will be outflowing through the orifice in partition and through the slot which is created between the partition and piston crowns. This last stream is swirled on the partition edge, what causes decrease of the stream speed outflowed from the orifice in partition to main combustion chamber. If the ignition advance angle is too big, then a peak pressure and compression work is very big because the burned gases are compressed instead of the fresh air/fuel mixture. This causes that the effective work is small and combustion efficiency is small.

12

Influence of ignition advance angle on combustion in internal combustion spark ignition engines with semi open combustion chamber

Leżański T., Sęczyk J., Wolański P.

Silniki Spalinowe

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2009

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R. 48, SC2

365--370

EN

In this paper the research results of combustion system of spark ignition engines with semi open combustion chamber has been presented. The major stress in this research has been put on determining of influence of the ignition advance angle on combustion. The research with using the rapid compression machine, the high speed photography system and the measuring system of high speed varied pressure has been carried out. The results include the images of combustion courses and the curves of high speed varied pressure. An angle of ignition advance influences the most evidently on engine performance in point of view combustion system with semi-open combustion chamber. Moreover it is the only parameter which may be permanently controlled during engine operation. Three cases of the ignition advance angle values has been considered in this research: a well suited angle, too small angle and too big angle advance. The best angle of ignition advance is if the beginning of the outflow of the burned gases and the radicals, from prechamber occurs when the piston reaches TDC. As results it will obtained high velosity of a flame front travelling through the main combustion chamber, a high maximum cycle pressure and a high combustion efficiency.

PL

W publikacji przedstawiono wyniki badań nowego systemu spalania z półotwartą komorą spalania, który może być stosowany w silnikach o zapłonie iskrowym. Największy nacisk w tych badaniach położono na wyjaśnienie wpływu kąta wyprzedzenia zapłonu na spalanie. W badaniach wykorzystano: maszynę pojedynczego sprężu, system szybkiej fotografii cieniowej, system pomiarów szybkozmiennych ciśnień. Wyniki obejmują: przebiegi spalania oraz przebiegi szybkozmiennych ciśnień. Badania wykazały, że kąt wyprzedzenia zapłonu ma najistotniejszy wpływ na przebieg spalania w systemie z półotwartą komorą spalania. Ponadto trzeba stwierdzić, że jest to jedyny parametr, który może być w sposób ciągły zmieniany podczas pracy silnika. Rozpatrzono trzy przypadki wartości kąta wyprzedzenia zapłonu: kiedy kat jest dobrze dobrany, kiedy jest zbyt mały i kiedy jest zbyt duży. Najkorzystniejsza wartość kąta wyprzedzenia zapłonu jest taka przy której początek wypływu strumienia palących się gazów i rodników z komory wstępnej do zasadniczej następuje wówczas kiedy tłok znajduje się w położeniu GMP.

13

Using of high speed photography to research of ignition process in SI engines with semi open combustion chamber

Leżanski T., Sęczyk J., Siwiec S., Wolański P.

Journal of KONES

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2009

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Vol. 16, No. 4

277-286

EN

The results of the research into visualisation of the ignition process in a combustion system with divided, semi open combustion chamber, for SI engines are presented in this paper. In this combustion system the original combustion chamber was divided, by partition, into prechamber and the main combustion chamber. Initiation of the ignition had place in the prechamber using electric spark plug. Expected results of the research of this combustion system were: shortening ofcombustion time in all combustion chambers, reduction of exhaust emission and increased engine efficiency. The research was focused on experimental study of flame propagation during ignition and combustion into the prechamber when the point of ignition was placed in the wali of the prechamber opposite to the ońfice in the prechamber, in the middle of the prechamber and in the orifice in the partition. The rapid compression machine (RCM) was used in the experimental research to facilitate visualisation of the process. This high speed Schlieren photography system and high speed pressure measurement system were used to record path of combustion and pressure variation in the combustion chamber. The best results were obtained when the point of ignition was placed at the wali of the prechamber, it was probably caused by flame front turbulisation immediately after ignition initiation. In this case the shortest time of combustion and the highest maximum cycle pressure were achieved resulting in the maximum combustion efficiency and minimum exhaust emission. If the point of ignition was placed in the middle of the prechamber or in the orifice in the partition, immediately after ignition initiation the laminar flame front was observed. This flame front was turbulised after some time from ignition initiation, however, the time to turbulisation was shortened in the case of the ignition in the middle of the prechamber. As a result, the combustion time after ignition initiation in the orifice in the partition was close to one in the original combustion chamber. Pictures in the paper present black-white high speed photography of the flame front development after ignition initiation for different ignition placements and the curves of flame front travel after the ignition.

PL

W publikacji przedstawiono wyniki badań wizualizacyjnych procesu zapłonu w systemie spalania z dzieloną, półotwartą komorą spalania przeznaczonego dla silników o zapłonie iskrowym. System charakteryzuje się podziałem standardowej komory spalania na komorę wstępną i zasadniczą. Inicjacja zapłonu od świecy elektrycznej ma miejsce w komorze wstępnej. Przedmiotem badań był przebieg zapłonu i spalania mieszaniny w komorze wstępnej, w przypadku umieszczenia elektrod świecy zapłonowej: na ściance, w środku komory wstępnej, w otworze w przegrodzie łączącym komorę wstępną z komorą zasadniczą. Badania prowadzono przy zastosowaniu maszyny pojedynczego sprężu co pozwoliło ułatwić wizualizację procesu. Wraz z rejestracją przebiegu spalania na taśmie filmowej rejestrowano przebieg zmian ciśnienia w komorze spalania. Najlepsze efekt uzyskano w przypadku miejsca inicjacji zapłonu na ściance komory wstępnej. Wówczas czas spalania był najkrótszy, ponieważ spalanie miało charakter turbulentny. W przypadku zapłonu w środku komory wstępnej i zapłonu w otworze spalanie, bezpośrednio po zapłonie, miało charakter laminarny i dopiero po pewnym czasie następowała turbulizacja płomienia, z tym, że l w przypadku zapłonu w otworze czas ten był bardzo długi. W efekcie czas spalania, w przypadku zapłonu w otworze, j był bardzo zbliżony do czasu spalania w komorze standardowej. Najkrótsze czasy spalania uzyskiwano w przypadku zapłonu na ściance, co wyraźnie można ocenić na wykresach i fotografiach przebiegu spalania.

14

Research of influence of design parameters on combustion system operation for SI engines

Leżanski T., Sęczyk J., Wolański P.

Journal of KONES

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2009

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Vol. 16, No. 4

265-276

EN

The summary of the investigation performed with a new combustion system with divided semi-open combustion chambers for SI engines while using rapid compression machine (RCM) is presented in this paper. Division of the combustion chamber with partition to the prechamber and the main combustion chamber exists only when the piston is close to the TDC, for the rest of the cycle the chambers are fully open. Variable parameters of the combustion system during the tests were: ratio of the prechamber volume to the sum of the prechamber and main combustion chamber volumes, diameter of the orifice in the partition, point of the ignition and ignition advance angle (ignition timing). Constant parametr es were: RCM speed — 1800 rpm, and stoichometric mixture of air to natural gas- it contained 96% ofmethane. research results show that the ignition advance angle, which ensures the optimal results, has to be adjusted for each configuration of the RCM design parameters. The influence of prechamber volume, orifice diameter, point of ingnition and ignition advance angle on combustion process in the combustion chamber was analysed. If the prechamber volume is too small the energy of the stream is small and the stream has a small range. Its energy is too small to travel through all the main combustion chamber with the speed greater than the combustion speed. The partition orifice diameter influences on the time from the start of the ignition to the beginning of the stream outflow.from prechamber to the main combustion chamber and the stream energy. The biggest influence on stream formation process has the placement of the ignition and the best results are obtained when the ignition occured on the prechamber wall. The high speed Schilieren photographs of the combustion process of the most characteristic cases and of the travel of the flame front curves are shown in this paper. The research results show the direction of the trade - off investigation of commercial SI engine for a wide range of engine speed and loads.

PL

W publikacji podsumowano wyniki badań prowadzonych nad nowym systemem spalania dla silników o zapłonie iskrowym, w którym dokonano podziału standardowej komory spalania na komorę wstępną i komorę zasadniczą. Przy tym podział ten występuje wyraźnie tylko wówczas, kiedy tłok znajduje się w pobliżu GMP. Badania prowadzono przy zastosowaniu maszyny pojedynczego sprężu. Zmiennymi parametrami konstrukcyjnymi były: stosunek objętości komory wstępnej do całkowitej objętości komory spalania, średnica otworu w przegrodzie łączącego komorę wstępną z komorą zasadniczą, miejsce zapłonu. Badania prowadzono przy różnych wartościach kąta wyprzedzenia zapłonu, przy stałej prędkości obrotowej wału korbowego 1800 obr./min. Paliwem była stechiometryczna mieszanina powietrza z gazem ziemnym zawierającym 96% metanu. Wyniki badań wskazują, że dla uzyskania pozytywnego efektu konieczne jest dobranie odpowiedniego kąta wyprzedzenia zapłonu dla każdej konfiguracji parametrów konstrukcyjnych (objętość komory wstępnej, średnica otworu w przegrodzie, miejsce zapłonu). W pracy przeanalizowano wypływ: stosunku objętości komór spalania wstępnej do zasadniczej, średnicy otworu w przegrodzie oraz miejsca zapłonu na przebieg spalania i stwierdzono, że przy zbyt małej objętości komory spalania energia strugi jest zbyt mała, aby przemieścić się z dużą prędkością przez całą zasadniczą komorę spalania, większą niż prędkość spalania w komorze standardowej. Średnica otworu w przegrodzie wpływa zarówno na czas od początku zapłonu do początku wypływu jak i energię strugi. Miejsce zapłonu najsilniej wpływa na proces tworzenia się strugi. W publikacji przedstawiono fotografie z przebiegiem spalania w najbardziej charakterystycznych przypadkach oraz wykresy przemieszczeń czoła płomienia w przypadku różnych fotografii parametrów badań

15

Research of combustion system with semiopen combustion chamber in a commercial spark ignition engine

Leżanski T., Sęczyk J., Wolański P.

Journal of KONES

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2009

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Vol. 16, No. 3

203-211

EN

During the research of a new combustion system with semi-open combustion chamber for SI engines with use of the rapid compression machine (RCM) and visualisation experimental engine (VEE) it was proved that the application of this system results in shortening of the combustion time, increasing of the maximum cycle pressure and, in effect, increase of the combustion efficiency. The aim of the research using a commercial spark ignition engine was to prove that the similar results (as in RCM and VEE) could be obtained in a wide range of automotive engine operating parameters. In this research the two cylinder, four stroke air cooled SI engine, with volume displacement 650 cm3 from Fiat 126 motorcar was used. This engine was fitted with a modified cylinder head and ignition distributor. Two types ofprechamber with different shape were installed in different locations into the cylinder head but the ignition distributor had fixed, preadjusted, ignition advance angle in the full range of engine speed. The wide open throttle characteristics including power, specific fuel consumption and exhaust emission versus engine speed and load characteristics including: specific fuel consumption and exhaust emission versus engine torque were determined for different ignition advance angles. In the lower range of the ignition advance angle the engine showed stable operation at lower speed but unstable at high speed and, inversely, if the ignition advance angle was high the engine operation was stable at the higher speed and unstable at the lower. The engine characteristics during unstable operation were deteriorating. The research results show that improvement of the engine characteristics can be obtained in the full range of operating parameters ifthe ignition advance angle is varied continuously with the variation of engine speed. The ignition advance angle for the engine fitted with the new combustion system, which was subject of this research, was different form the ignition advance angle for standard engine.

PL

W badaniach prowadzonych przy zastosowaniu maszyny pojedynczego sprężu oraz badawczego silnika wizualizacyjnego, stwierdzono, że zastosowanie systemu z półotwartą komorą spalania może spowodować: skrócenie czasu spalania w komorze spalania, zwiększenie ciśnienia maksymalnego cyklu oraz zwiększenie sprawności spalania. Celem badAn w silniku produkcyjnym było wykazanie, że takie pozytywne efekty można uzyskać również w szerokim zakresie parametrów pracy trakcyjnego silnika spalinowego. Badania prowadzono przy zastosowaniu silnika samochodu Fiat 126p. W badaniach stosowano dwie różne głowice, w których zainstalowano w różnych miejscach i o różnym kształcie wstępną komore spalania oraz zmodernizowany aparat zapłonowy. Określono charakterystyki zewnętrzne i obciążenlowe przy różnych konfiguracjach komory spalania, różnych wartościach kąta wyprzedzenia zapłonu dla dwóch wartości współczynnika nadmiaru powietrza. W przypadku małych wartości kąta wyprzedzenia zapłonu uzyskiwano poprawę osiągów oraz zmniejszenie toksyczności spalin w zakresie niskich prędkości obrotowych, natomiast silnik pracował niestabilnie w zakresie wysokich prędkości obrotowych i odwrotnie, kiedy stosowano wysokie wartości kąta wyprzedzenia zapłonu uzyskiwano poprawę osiągów w zakresie wysokich prędkości obrotowych, natomiast silnik pracował niestabilnie w zakresie niskich wartości prędkości obrotowych. Uzyskane wyniki pokazują, że dzięki zastosowaniu systemu z półotwartą komorą spalania, o właściwie dobranych parametrach systemu, można uzyskać poprawę osiągów silnika oraz zmniejszenie toksyczności spalin w całym zakresie pracy silnika trakcyjnego

16

Some problems of improvement of fuel efficiency and emissions in internal combustion engines

Jankowski A., Sandel A., Sęczyk J., Siemińska-Jankowska B.

Journal of KONES

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2002

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Vol. 9, No. 1-2

333-356

EN

Analysis of some design for both compression ignition and spark ignition engines which give improvement from point of view fuel efficiency and pollutant emission including CO2 are presented in the paper. Actual and future standards requirement for pollutant emissions and CO2 as well test procedures, generally for light duty car for Californian standards and European standards are overviedwed. Especially common rail system for compression ignition and spark ignition engines were presented. Air assist system which can be applied for four stroke and two stroke engines was described too. Gasoline direct injection system which operate in 2 modes: lean burn mixture when engine run with a part load and homogeneous charge with stoichiometric mixture when engine run with high load is presented. Lean stratified mixture is realized as a late fuel injection during compression stroke but homogenous charge is realized as a early fuel injection during induction stroke. Lean mixtures require to apply special de - NOx catalytyst which joined with three way catalytyst (TWC) enable meet of standard requirements concerning exhaust emission. Investigation concerning some solutions of mixture preparation process and combustion were conducted. Mixture preparation process investigations were conducted with laser Doppler equipment LDV (3D) and PDPA. Combustion processes ware conducted in constant volume chamber. During combustion process testing the flow field, fuel droplet dimension and structure of fuel spray profitable for ignition process close to spark plug was determined. If velocity of the droplet in spark plug was near zero and droplet dimension were small repeatable ignition for lean mixture was obtained.

17

Analysis of fuel spray preparation for internal combustion engines

Jankowski A., Sandel A., Sęczyk J., Siemińska-Jankowska B.

Journal of KONES

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2002

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Vol. 9, No. 1-2

323-332

EN

In this paper the results of the drop size and its distribution in fuel spray produced by common rail and air assist systems of injection have been presented. Measuring equipment and testing have been described. The laser systems: LDV, PDPA and RSA have been applied to perform of the measurements. The results show that by applying the common rail system and air assist system can be obtain similar size dimension of droplet in injected fuel spray. Introduction of very high pressure direct injection in CI engines, GDI and air - assist systems in SI engines were beneficial from the view point of emission and fuel consumption.

18

Measurement of drop size distribution in fuel sprays by laser methods

Jankowski A., Sandel A., Jankowska-Siemińska B., Sęczyk J.

Journal of KONES

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2001

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Vol. 8, No. 3-4

334-345

EN

Results of atomized fuel spray parameters measurement are presented in this paper, for an injector applied in common rail systems of CI engines as well as for an air-assist type petrol atomizer compared with a conventional petrol one. The measurements were carried out with the use of a dynamic, laser Doppler particle size and velocity analyzer (LDV and PDPA). It is shown that the both injection systems examined are capable of producing very fine atomization. The measuring set-up and equipment are described.

19

Badania strugi paliwa rozpylanej przez układ wtryskowy common rail

Jankowski A., Sęczyk J., Zbierski K.

Journal of KONES

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2000

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Vol. 7, No. 1-2

228-236

PL

Układy wtryskowe - Common Rail - są od kilku lat wprowadzane do samochodów osobowych z silnikami o zapłonie samoczynnym i bezpośrednim wtrysku paliwa. Jest ich jeszcze stosunkowo niewiele na rynku, ale już dzisiaj wydaje się, że powoli będą one wypierać konwencjonalne układy wtryskowe. Stąd, między innymi, wynika potrzeba prowadzenia obszernych badań, co czynione jest w wielu ośrodkach badawczych na świecie. W artykule, po scharakteryzowaniu takiego układu, opisano stanowisko do badań rozpylonej strugi paliwa, składające się z oprzyrządowanego układu wtryskowego systemu "Common Rail" oraz urządzeń pomocniczych a także urządzenie pomiarowe w postaci dopplerowskiego, dynamicznego analizatora wymiarów i prędkości kropel paliwa. Badania parametrów charakteryzujących rozpyloną strugę paliwa przeprowadzono w funkcji różnych wartości ciśnienia w kolektorze układu wtryskowego, w różnych miejscach strugi. W oparciu o uzyskane wyniki pomiarów ustalono między innymi zależności między zastępczymi średnicami kropel a ciśnieniem paliwa.

EN

The Common Rail injection systems have been introduced in the Diesel and gasoline direct injection engines for light duty vehicles and passanger cars for several years. Although at present they are not too numerous it seems that they will slowly conque the market. For this reason there is a vast amount of associated research carried out in research and development centers throughout the world. This paper, after an introduction into the subject, presents a description of a laboratory set-up for measuring sprays of atomized fuel. The set-up comprises the Common Rail injection system with accessories, auxiliary equipment and a laser doppler analyzer of sizes and velocities of droplets. Some results of the measurement have been quoted including the variation of atomization parameters as a function of pressure in Common Rail at various locations along the fuel spray. A correlation between droplet mean diameters of various definitions and fuel supply pressure has been worked from the measurement results.

20

Tłokowe silniki spalinowe zasilane mieszaniną gazu ziemnego i wodoru

Jankowski A., Sęczyk J.

Journal of KONES

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1998

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Vol. 5, No. 1

119-130

PL

W artykule przedstawiono wyniki badań silników zasilanych mieszaniną sprężonego gazu ziemnego i wodoru, z punktu widzenia toksyczności spalin. Wyniki badań wskazują, że zasilanie silników mieszaniną gazu ziemnego i wodoru powoduje rozszerzenie granic stabilnego spalania, szczególnie w zakresie ubogiej mieszanki, w stosunku do silników zasilanych samym gazem ziemnym, co umożliwia zmniejszenie zawartości wszystkich składników toksycznych w spalinach. Wyniki badań prowadzonych przez różnych badaczy są na ogół zgodne w odniesieniu do CO i HC nie są natomiast jednoznaczne w odniesieniu do emisji tlenków azotu. W zakresie emisji tlenków azotu uzyskiwano zarówno mniejsze wyniki przy zasilaniu mieszaniną gazu ziemnego i wodoru jak i w odniesieniu do samego gazu ziemnego. Wprowadzenie zasilania silników mieszaniną gazu ziemnego i wodoru jest procesem przejściowym prowadzącym do zasilania silników czystym wodorem.

EN

The results of exhaust emission testing of the engines with a mixture of compressed natural gas and hydrogen fuelled, are presented in this paper. As may be concluded the lean stability limit for this type of mixture is shifted in comparison with the one obtained for engines fed with pure compressed natural gas, allowing a reduction of all toxic constituent of the exhaust. Reports by various authors are in good agreement as far as the CO and HC emissions are concerned, but they show some discrepancies with reference to NOX emissions. Some authors report lower NOX contents for compressed natural gas / hydrogen mixture while others indicate lower NOX for pure natural gas. The investigation of the natural gas / hydrogen mixture as fuel is a prelude to the future use of the pure hydrogen.