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Wyszukujesz frazę "HCCI" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
HCCI engine - idea and expectations. Case study
Autorzy:
Kowalewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/244203.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
HCCI engine
auto-ignition control
Opis:
Internal combustion engines yet have not exhausted their development possibilities in the range of economy and ecology demands. Development of SI and CI engines, which several years ago proceeded individually in-parallel, now becomes likely in common: one type of engine shares some features with the other one, e.g. direct injection, electronically controlled injectors, electronic control unit etc. However, type of ignition and mixture formation are still different (spark assisted ignition versus auto ignition and homogeneous mixture versus heterogeneous). HCCI engine overcomes this difference. At present HCCI engine uses both type of ignition modes and both types of mixture in different ranges of operational parameters. Direct injection during compression stroke and stratified charge are characteristics for low and mild power resulting in low emission of CO and HC as well as NOx. Combustion is initiated by spark when mixture is very poor. For maximum load and speed, auto-ignition of homogeneous stoichiometric mixture takes place in the whole volume of combustion chamber. Due to the absence of flame and low temperature, nitrogen oxides, of which molecules arise in post flame zone, are low. Also emission of CO and HC are low due to stoichiometry of the mixture. The key problem is controlled auto-ignition as a function of speed and load (fully HCCI engine). Several methods of auto-ignition control (CAI) are discussed in this paper.
Źródło:
Journal of KONES; 2008, 15, 2; 217-224
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the ignition control in the HCCI system using dose of monoatomic inert gas
Autorzy:
Postrzednik, S.
Przybyła, G.
Żmudka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/248032.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
IC engine
HCCI system
ignition control
charge compression
Opis:
The subject of the analysis presented in the paper is the idea and implementation method of the ignition point of homogeneous air-fuel mixture, used in the IC engine with HCCI system. Autoignition of the combustible mixture can occur only upon reaching the characteristic self-ignition temperature Tz. It should take place during (near end) the load compression. In order to achieve the fuel mixture ignition temperature Tz in the system, usually it is proposed adjusting the engine compression ratio, epsilon. However, it is quite cumbersome especially in case of frequent changes of engine load (there are also difficulties with the precise advance angle adjusting of fuel mixture ignition). According to our conception, the other method of autoignition adjustment can be successfully applied. The essence of the new idea consists in proper selection, according to engine load, of the exponent k of charge polytropic compression. Introducing the defined dose of monoatomic gas (e.g. argon Ar,k almost equal 1.667) to air-fuel mixture, the higher values of the polytropic compression exponent .. of working medium can be achieved. It will result in significant increase of the temperature rise Delta Tmax of the compressed charge and accordingly progressive increase of the advance angle of the mixture ignition.
Źródło:
Journal of KONES; 2012, 19, 1; 319-326
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduction of pressure rise rates in boosted HCCI engine using advanced valve actuation strategies
Autorzy:
Hunicz, J.
Rybak, A.
Gęca, M.
Powiązania:
https://bibliotekanauki.pl/articles/243727.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
low temperature combustion
HCCI
valve actuation
combustion harshness
Opis:
Homogeneous Charge Compression Ignition (HCCI) is a promising low temperature combustion technology which offers high fuel efficiency and extremely low exhaust emissions. However, there are still some pending issues to be resolved before the technology will achieve mass production level. Namely, combustion controllability should be improved and HCCI operating range should be widen. The latter is constrained by excessive combustion rates under high loads. In this study, advanced variable valve actuation strategies were applied to control auto-ignition timings and combustion rates. The examinations were conducted using single-cylinder research engine fuelled with directly injected gasoline. The HCCI combustion was achieved using negative valve overlap technique. The engine was run under boosted conditions, in an operation regime where acceptable pressure rise rate (PRR) level is usually exceeded. Selected valve timing sweeps were carried out within a scope of the experiments to evaluate PRR reduction potential. The obtained results manifested superior combustion controllability. Late exhaust valve closing enabled reduction of the amount of internally re-circulated exhaust, which propagated to the main event combustion. From the intake side, two effects were observed, i.e. variability of the intake air aspiration and variability of the apparent compression ratio. Both phenomena were found to affect combustion timings and rates.
Źródło:
Journal of KONES; 2018, 25, 4; 369-376
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of work of an engine working with combustion initiation from ignition dose of fuel
Autorzy:
Sendyka, B.
Mitianiec, W.
Noga, M.
Powiązania:
https://bibliotekanauki.pl/articles/245989.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
modelling
simulation
combustion engine
HCCI
two stage injection system
Opis:
The paper presents analysis of fuelling and of the course of combustion process for a two-cycle engine. The main idea of the engine according to patent solution of Prof. B. Sendyka consists in the fact that engine work begins from spark ignition, whereas, at higher load and higher temperature in the cooling system there occurs switching off spark ignition and transition to ignition from an ignition dose injected directly into the combustion chamber. Such an engine possesses two injection systems: one system of multi-point injection which forms homogenous mixture, whereas, the other system of direct injection is used for ignition dose injection only. After injection of the ignition dose of a very small mass combustion is initiated on the basis of formation of auto-ignition centres so as it takes place during knock combustion. Auto-ignition centres initiate combustion of the basic charge. Simulation was carried out in order to perform analysis occurring phenomena of fuel feeding and combustion. Works on it started from elaboration of a computational grid of the engine and subsequently analysis of indicated diagrams of engine work with injection of ignition dose was performed. Analysis was also performed of temperature traces and of traces of charge mass change in the cylinder as well as of participation of the mass of basic fuel dose in the cylinder in function of the crank angle. Moreover visualization of effects of the process of mixture formation and combustion was performed and presented in form of illustrations of charge temperature distribution, fraction of fuel ignition and basic dose vapours in cross-sections of the combustion chamber.
Źródło:
Journal of KONES; 2011, 18, 3; 395-403
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigations of various modes of charging on HCCI engine
Autorzy:
Prasad, A. Renuka
Bhandari, Rakesh
Jagadish, Donepudi
Powiązania:
https://bibliotekanauki.pl/articles/245191.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
HCCI technology
homogeneous mixture
thermal efficiency
combustion rate
emissions
Opis:
Homogeneous Charged Compression Ignition technology is most favourable or suitable for Internal Combustion engines for reducing the exhaust emissions and enhances the Thermal efficiency, improve the fuel consumption, and increase the rate of combustion. This article represents the various charging methods on HCCI technology engine; it improves the engine performance and determines the emission characteristics of HCCI technology engine. The homogeneous mixture prepared with different methods. In –cylinder internal homogeneous mixture preparation method applied in this present work. It reduces the exhaust emissions released from the combustion chamber. However, oxides of nitrogen and soot emissions are significantly reduce, because combustion starts at lower temperatures and various points in combustion chamber. The HCCI technology generates small amount of exhaust emissions and it improves the performance of the engine. In addition, performance and released emissions depends on the quality and quantity of homogeneous mixture.
Źródło:
Journal of KONES; 2019, 26, 1; 119-126
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increase of high load limit in a gasoline HCCI engine
Autorzy:
Hunicz, J.
Kordos, P.
Gęca, M.
Powiązania:
https://bibliotekanauki.pl/articles/242189.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
HCCI engine
negative valve overlap
high load limit
mechanical boost
Opis:
Engine operation in HCCI mode allows for improvement of thermal efficiency and substantial reduction NOX emission. The most production feasible solution for gasoline HCCI engine is application of exhaust gas trapping using a negative valve overlap. This technique increases thermal energy of a mixture, thus allowing for auto-ignition at moderate compression ratios. However, high exhaust gas re-circulation rate decreases volumetric efficiency. As a result, achievable engine loads are also reduced. Supercharging can be applied in order to improve volumetric efficiency and extend high load limit. However, increase of amount of intake air can lead to reduction of start of compression temperature via decrease of residuals in a mixture. In order achieve HCCI mode of combustion, temperature of start of compression must be kept within narrow limits. In this study experimental and modeling investigations were presented. Experiments were carried out using single cylinder research engine. The engine was equipped with fully variable valvetrain and direct gasoline injection. Application of mechanical boosting allowed for widening achievable load range in HCCI mode of operation. Numerical calculations allowed for determination of admissible valvetrain settings and intake pressure, which guarantee proper temperature of start of compression.
Źródło:
Journal of KONES; 2012, 19, 4; 231-238
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary investigations of the HCCI combustion system in a single cylinder research engine
Autorzy:
Motyl, K.
Lisowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/246468.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
thermodynamics
internal combustion engines
HCCI
combustion process
exhaust emission
bio-fuel
Opis:
This paper describes the results of the preliminary experimental research of the HCCI combustion system in a single cylinder research engine fuelled by means of natural gas containing 95% methane. In this research, influence of the initial temperature of the charge and mixture composition on the maximum combustion pressure, maximum speed of pressure growth, selfignition delay time, combustion time, maximum combustion temperature, heat release and combustion efficiency have been studied. The paper contains: description of the engine modification to adopt it for HCCI operation requirements, applied measurements equipment, selected results of the experimental research. The results shows that initial charge temperature and mixture composition (relative air/fuel ratio coefficient) have essential influence on the engine operating results. The experimental research has been conducted for the varied initial charge temperature from 140 centigrade up to 210 centigrade and for varied relative air/fuel ratio coefficient 1=1; 1=1.5; 1=1.7; 1=2. Maximum charge pressure, maximum speed of pressure growth selfignition delay time was rather unaffected on the initial charge temperature increase beyond 200 centigrade. Previous and current author's research works have indicated that extremely low emissions and high combustion efficiencies are possible to reach if homogeneous charge compression ignition is applied.
Źródło:
Journal of KONES; 2007, 14, 3; 429-436
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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