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Wyszukujesz frazę "Sementa, P." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
Optical diagnostics in a spark ignition engine for two-wheel vehicles
Autorzy:
Merola, S. S.
Sementa, P.
Tornatore, C.
Powiązania:
https://bibliotekanauki.pl/articles/247811.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark ignition engine
gasoline
2-wheel vehicle
optical diagnostics
digital imaging
spectroscopy
Opis:
Different optical techniques were applied to describe the thermal and chemical processes that occur in a SI small engine from the ported fuel injection and in-cylinder mixture formation to the combustion process and the exhaust emission. In PFI SI engines, the atomized fuel is sprayed towards the intake valves, where it may evaporate, puddle or rebound. Furthermore, a portion of the fuel may flow directly into the cylinder or impinge upon the port walls. These phenomena occur in varying degrees and depend upon the engine design, injector location and engine operation. Potentially the fuel can enter the cylinder in a poorly atomized state, leading to an increased unburned hydrocarbon emissions. This is particularly true during cold operation, when evaporation is low. In the small-motorcycle and scooter engines the fuel injection occurs in smaller intake manifold than light-duty vehicle engines, increasing the criticism of the fuel-wall interaction. The experimental investigations were performed in a single cylinder engine constituted by an elongated optically accessible piston and equipped with the head and injection system of a reference 4-stroke engine for small vehicles. High spatial resolution imaging was used to characterize the fuel injection phase. The cycle resolved visualization was performed to follow the flame propagation from the intake spark ignition to the exhaust phase. Natural emission spectroscopy measurements were applied in the ultraviolet-visible wavelength range to identify the chemical species that are markers of the combustion process and to follow the formation of pollutants.
Źródło:
Journal of KONES; 2010, 17, 4; 323-336
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of fuel film deposition on combustion process in PFI SI engine
Autorzy:
Merola, S. S.
Sementa, P.
Tornatore, C.
Vaglieco, B. M.
Powiązania:
https://bibliotekanauki.pl/articles/246434.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Overboosting
spark ignition engine
optical diagnostics
fuel film deposition
Opis:
The present paper discusses the experimental investigations on the flame induced by fuel film deposition ignition in a single cylinder, ported fuel injection, four-stroke, over-boosted spark-ignition engine with a four-valve production head. The engine was optically accessible and equipped with a transparent quartz window in the bottom of the combustion chamber. 2D-digital imaging and UV-visible natural emission spectroscopy were used to follow the flame propagation in the combustion chamber. Two colour pyrometers were applied to evaluate flame temperature and soot concentration. Particulate matter and soot primary particles diameters were measured and correlated with the soot amount produced in the combustion chamber. The effect of the intake air pressure and injection phasing was investigated. Optical setup for spectroscopic measurements and visible digital imaging, visible flame emission detected in the chamber for the selected operating conditions, visible emission spectra measured at 60 CAD ASOS in the chamber, soot concentration measured at the selected operating conditions, integral soot concentration measured at the selected operating conditions, particulate mass concentration measured by the Opacimeter and particles number concentration measured by LII at the engine exhaust are presented in the paper.
Źródło:
Journal of KONES; 2007, 14, 3; 395-402
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the fuel injection splitting on the combustion process in a PFI boosted spark-ignition engine
Autorzy:
Merola, S. S.
Sementa, P.
Tornatore, C.
Vaglieco, B. M.
Powiązania:
https://bibliotekanauki.pl/articles/244873.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
PFI SI engine
boosting
double injection strategies
fuel deposits
optical diagnostics
Opis:
Future stringent legislation on emissions in combination with the market request of an increase in engine efficiency and optimization poses a great challenge to the engine and components manufacturers. The technologies developed in the last years for Spark Ignition (SI) engines such as turbocharging and variable valve actuation are not able to totally satisfy the future normative. More progress still has to be made in terms of in-cylinder combustion process and efficiency. The aim of this paper is the optimisation of a boosted SI engine in terms of performances, fuel consumption and pollutants emissions with low costs. The experimental activity was carried out on a port fuel injection SI optical engine, equipped with a commercial four-valve head. Innovative injection strategies were tested: in particular, single and double injections were performed when the intake valves were open. Optical techniques based on 2D-digital imaging were used to follow the fuel injection in the intake manifold and simultaneously the flame propagation in the combustion chamber. Conventional measurements of engine parameters and exhaust emissions completed the experimental investigations. The tests demonstrated that the double injection strategies were characterized by higher combustion process efficiency than single injection on. The injection splitting resulted a suitable solution for the reduction in pollutants concentration in the combustion chamber and at the exhaust with a good compromise between performance and fuel consumption.
Źródło:
Journal of KONES; 2008, 15, 4; 331-339
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the fuel injection pressure on the combustion process in a PFI boosted spark-ignition engine
Autorzy:
Merola, S. S.
Sementa, P.
Tornatore, C.
Vaglieco, B. M.
Powiązania:
https://bibliotekanauki.pl/articles/244891.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
PFI SI engine
boosting
fuel injection
fuel deposition
optical diagnostics
Opis:
In this paper, low-cost solutions were proposed to reduce the fuel consumption in a boosted port fuel injection spark ignition (PFI SI) engine, taking into account the engine performances and the pollutants emission. To this purpose, the optical characterization of the fuel injection and of the combustion process was carried out in a PFI SI engine. The experiments were performed on a partially transparent single-cylinder SI engine, equipped with a four-valve head and an external boost device. The intake manifold was optically accessible through three holes that allowed the introduction of an endoscope and of optical fibres. The standard injection condition planned by the engine manufacturer was investigated; it consisted in the fuel injection at 3.5 bar when the intake valves were closed. Moreover, the fuel injection with open intake valves was tested; 3.5 and 6.5 bar fuel pressures were studied for open and closed valves conditions. Optical techniques based on 2D-digital imaging were used to follow the fuel injection spray in the intake manifold and the flame propagation in the combustion chamber. The results of in-cylinder optical investigations were correlated with the engine performances and with the exhaust emissions.
Źródło:
Journal of KONES; 2008, 15, 4; 341-349
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical diagnostics of the cyclic variation in the kernel development and abnormal combustion: SI boosted engine
Autorzy:
Gallardo-Ruiz, J. M.
Ballais, R.
Merola, S. S.
Sementa, P.
Tornatore, C.
Powiązania:
https://bibliotekanauki.pl/articles/246898.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
optical diagnostics
cycle-to-cycle variation
flame kernel
abnormal combustion
SI boosted engine
Opis:
The combustion stability of a spark ignition engine significantly influences its performances. The cyclic variation is generally evaluated by the fluctuation of in-cylinder peak pressure which changes in both magnitude and position measured from TDC. In this work the cyclic variation of combustion process were analysed as function of crank angles. The different SI engine process phases were investigated. The pressure related data were correlated with cycle resolved visualization measurements. The cycle resolved digital imaging was applied to follow the kernel inception and growth and to study the flame front propagation until the exhaust phase. A custom numerical post-detection procedure was applied to correlate the optical data from the integral luminous signal measured in the combustion chamber with the pressure related parameters .The flame kernel and the abnormal combustion due to the fuel deposits burning resulted particular relevant for the cycle-to-cycle variations. Optical measurements outlined better than pressure related analysis the role of the early andfinal stages of the combustion process. The experiments were performed in a 400 cm3 single cylinder, port fuel injection, four-stroke spark ignition engine. The engine was optical accessible with the same geometrical parameters as a 1600 cm3 passenger car engine. The head and the injection system of a commercial engine mounted on a passenger car were used. Standard EURO IV gasoline was used
Źródło:
Journal of KONES; 2010, 17, 2; 103-111
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical diagnostics of the cycle-to-cycle variation in the kernel development and abnormal combustion: SI small engine
Autorzy:
Ballais, R.
Gallardo-Ruiz, J. M.
Merola, S. S.
Sementa, P.
Tornatore, C.
Powiązania:
https://bibliotekanauki.pl/articles/950078.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
optical diagnostics
cycle-to-cycle variation
flame kernel
abnormal combustion
SI engine
Opis:
The combustion stability and more in details the cyclic variability significantly influences the performance and the pollutant emissions of a spark ignition engine. In this work, an experimental research activity was carried out to investigate the influence of the different combustion phases on the cycle-to-cycle variation. In particular the flame kernel development and the fuel deposits burning were investigated by in-cylinder pressure measurements and optical investigations. Engine cycle resolved visualization was applied to characterize the spatial evolution of the flame front from the spark ignition until the exhaust phase. A numerical custom post-detection procedure was used to correlate the optical data with the pressure related parameters during the combustion process. The simultaneous use of optical diagnostics and pressure related analysis demonstrated the fundamental role of the first stage and late phase of the combustion on the spark ignition engine process. Flame kernel and diffusion controlled flame due to fuel deposits burning dominated the cyclic variability of in-cylinder combustion. The experiments were realized in a 250 cm3 single cylinder, port fuel injection, four-stroke spark ignition engine. The engine was optically accessible and it was equipped with the head, injection system and exhaust device of a commercial engine mounted on small motorcycles and scooters. Standard EURO IVgasoline was used.
Źródło:
Journal of KONES; 2010, 17, 2; 17-25
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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