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1
Content available Possible applications of prechambers in hydrogen internal combustion engines
Matla Jędrzej
Combustion Engines
|
2022
|
R. 61, nr 4
77--82
EN
In order to ensure better control of the combustion process in a internal combustion engine powered by hydrogen, it has been proposed to use a split combustion chamber solution. Following paper contains a description of a hydrogen combustion system that includes an analysis of possible technical solutions. The considerations take into account the issues of the dual nature of hydrogen knocking and the problem of burning a stratified charge of a hydrogen-air mixture in a cylinder.
2
Content available Influences of the pre-chamber orifices on the combustion behavior in a constant volume chamber simulating pre-chamber type medium-speed gas engines
Wakasugi Takuya, Tsuru Daisuke, Tashima Hiroshi
Combustion Engines
|
2022
|
R. 61, nr 4
66--76
EN
The study aims to clarify the influence of pre-chamber (PC) configurations on the combustion process in the main chamber (MC) of medium-speed spark-ignition gas engines equipped with an active PC. A constant volume combustion chamber was prepared to simulate the chamber configurations of the gas engines. A high-speed shadowgraph was applied to visualize the torch flame development and the combustion process in the MC. Experiments were done by changing the charged gas in the MC, the number, and the diameter of the PC orifices. Combustion was most accelerated when the PC orifice configuration was set appropriately so that the adjacent torch flames would combine with each other. It was also found that the unburned mixture in the PC, which ejected prior to the torch flame, supported the penetration of the torch flame.
3
Content available Prechamber optimal selection for a two stage turbulent jet ignition type combustion system in CNG-fuelled engine
Pielecha Ireneusz, Bueschke Wojciech, Skowron Maciej, Fiedkiewicz Łukasz, Szwajca Filip
Combustion Engines
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2019
|
R. 58, nr 1
16--26
EN
Searching for further reduction of fuel consumption simultaneously with the reduction of toxic compounds emission new systems for lean-mixture combustion for SI engines are being discussed by many manufacturers. Within the European GasOn-Project (Gas Only Internal Combustion Engines) the two-stage combustion and Turbulent Jet Ignition concept for CNG-fuelled high speed engine has been proposed and thoroughly investigated where the reduction of gas consumption and increasing of engine efficiency together with the reduction of emission, especially CO2 was expected. In the investigated cases the lean-burn combustion process was conducted with selection of the most effective pre-combustion chamber. The experimental investigations have been performed on single-cylinder AVL5804 research engine, which has been modified to SI and CNG fuelling. For the analysis of the thermodynamic, operational and emission indexes very advanced equipment has been applied. Based on the measuring results achieved for different pre-chamber configurations the extended methodology of polioptimization by pre-chamber selection and the shape of main chamber in the piston crown for proposed combustion system has been described and discussed. The results of the three versions of the optimization methods have been comparatively summarized in conclusions.
4
Content available Experimental comparison of efficiency and emission levels of four-cylinder lean-burn passenger car-sized CNG engines with different ignition concepts
Soltic Patric, Hilfiker Thomas, Hutter Richard, Hänggi Severin
Combustion Engines
|
2019
|
R. 58, nr 1
27--35
EN
Today’s passenger car CNG engines are based on petrol engines which typically have restrictions preventing the exploitation of the full potential of methane based fuels, especially if they have to be operated also on petrol as a second fuel. Additionally, the use of threeway-catalysis limits the engine operation to λ = 1. Here, we present the efficiency potential and the raw emission characteristics for a dedicated four cylinder passenger car CNG engine without sticking to the usual combustion peak pressure and λ limitations. Lean combustion reduces the knocking tendency but, because of the higher pressure levels, increases the ignition energy demand. Therefore, different ignition systems (spark plug, prechamber, Diesel pilot) have been used.
5
Content available Comparative study on combustion characteristics of lean premixed CH4/air mixtures in RCM using spark ignition and turbulent jet ignition in terms of orifices angular position change
Bueschke Wojciech, Skowron Maciej, Wisłocki Krzysztof, Szwajca Filip
Combustion Engines
|
2019
|
R. 58, nr 1
36--41
EN
The increase in ignitability consist a main aim of implementation of the turbulent jet ignition (TJI) in relation to the combustion of diluted charges. Such an ignition system has been introduced to the lean-burn CNG engine in the scope of GasOn-Project (Gas Only Internal Combustion Engines). In this study the impact of TJI application on the main combustion indexes has been investigated using RCM and analyzed on the bases of the indicating and optical observations data. The images have been recorded using LaVision HSS5 camera and post-processed with Davis software. Second part of the study based on indicating measurements consist the analysis of combustion regarding the variation in the geometry of pre-chamber nozzles. It has been noted, that combustion with TJI indicates significantly bigger flame luminescence and simultaneously - faster flame front development, than the combustion initiated with conventional SI. The positive impact of nozzles angular position on engine operational data has been found in the static charge movement conditions, regarding the combustion stability.
6
Content available Theoretical analysis of air-fuel mixture formation in the combustion chambers of the gas engine with two-stage combustion system
Jamrozik A., Tutak W.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2014
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Vol. 62, nr 4
779--790
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.
7
Content available remote Model KIVA-3V jedno- i dwustopniowego systemu spalania w tłokowym silniku ZI
Sosnowski M., Jamrozik A., Kociszewski A., Tutak W.
Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Edukacja Techniczna i Informatyczna
|
2010
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T. 5
17-28
PL
W pracy przedstawiono porównanie wyników modelowania obiegu silnika ZI zasilanego mieszanką homogeniczną i realizującego jednostopniowy system spalania z wynikami modelowania obiegu silnika ZI zasilanego mieszanką heterogeniczną i realizującego dwustopniowy system spalania. Do modelowania obiegu silnika wykorzystano program KIVA-3V. Wyniki modelowania wykazały, że w efekcie zubażania homogenicznej mieszanki palnej w silniku z jednostopniowym systemem spalania powyżej λ=1,2, obniżeniu ulegają maksymalne wartości ciśnienia i temperatury obiegu, a przebieg procesu spalania w tym silniku niekorzystnie odbiega od przebiegu spalania mieszanki heterogenicznej w silniku z dwustopniowym systemem spalania o takim samym średnim współczynniku nadmiaru powietrza. Uzyskane charakterystyki szybkości wydzielania ciepła w procesie spalania i sumarycznej ilości ciepła wydzielonego podczas spalania dowodzą, że pomimo znacznego zubożenia mieszanki palnej, dla λ=2,0, proces spalania w tym silniku z dwustopniowym systemem spalania przebiegał dostatecznie szybko, aby możliwe było osiągnięcie odpowiednich osiągów silnika.
EN
This paper compares numerical modelling results of SI engine work cycle powered by homogeneous mixture with single-stage combustion system and SI engine work cycle powered by heterogeneous mixture with two-stage combustion system. The numerical model of the engine work cycle was built using KIVA 3V code. Numerical modelling results of engine work with single stage combustion system and homogenous mixture of average excess air factor greater than λ = 1,2 show decrease in maximal pressure and temperature values of engine cycle. The combustion phenomenon in this engine unfavourably differs from heterogeneous mixture combustion in two-stage combustion system engine of the same average excess air factor. Characteristics of the heat release rate during combustion and the total amount of heat generated during combustion show that despite a significant depletion of fuel mixture for λ = 2,0, the combustion process in the engine with two-stage combustion system was fast enough to reach a suitable engine performance.
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