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1

Evaluation of the injectors operational wear process based on optical fuel spray analysis

Pielecha I., Skowron M., Mazanek A.

Eksploatacja i Niezawodność

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2018

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Vol. 20, no. 1

83--89

EN

The diagnostics of combustion engine components currently requires the integration of many technical and scientific fields in order to quickly and accurately locate faults or pinpoint the causes of malfunction. This article analyzes the wear of injectors based on the geometric indicators of the fuel spray. Using a number of available parameter data, a selection has been made to best judge the wear of injectors in their operating conditions. Optical fuel spray tests were used to assess the injector wear. Various geometric indicators of the fuel stream have been presented, indicating their diagnostic utility and applicability. In conclusion, it was found that the current injection systems require the combination of mechanical injector diagnostics and advanced optical fuel spray diagnostics.

PL

Diagnostyka elementów silnika spalinowego wymaga obecnie integracji wielu dziedzin techniki i nauki w celu szybkiej i trafnej lokalizacji uszkodzenia lub poszukiwania przyczyn niesprawności. Artykuł dotyczy analizy zużycia wtryskiwaczy na podstawie wskaźników geometrycznych strugi rozpylanego paliwa. Na podstawie kilku dostępnych wielkości badawczych dokonano wyboru pozwalającego najlepiej ocenić zużycie wtryskiwaczy w warunkach ich eksploatacji. Do oceny diagnostycznej zużycia wtryskiwaczy wykorzystano badania optyczne rozpylenia paliwa. Przedstawiono różne wskaźniki geometryczne strugi paliwa, wskazując na ich użyteczność diagnostyczną oraz możliwość zastosowania. W podsumowaniu stwierdzono, że badania obecnych układów wtryskowych wymagają połączenia mechanicznych metod diagnostyki wtryskiwaczy oraz zaawansowanej diagnostyki optycznej rozpylenia paliwa.

2

Optical investigations of alternative fuel combustion in common rail compression ignition engine

Merola S. S., Tornatore C., Valentino G., Marchitto L.

Journal of KONES

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2012

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Vol. 19, No. 3

279-288

EN

The increasing global energy demand and the decreasing fossil-energy resources are enhancing the interest in the combustion characteristics of alternative fuels for diesel engines. Alternative-fuel combustion has been studied in detail in light-duty diesel engines, even if the comparison of test results from different chemical nature fuels obtained by integrated optical methodologies is lacking. Thus, it is the primary objective of the present study to characterize the combustion of selected alternative fuels in an optical common rail compression ignition engine by high-speed luminescence imaging and natural emission spectroscopy. The effects of the fuels on in-cylinder spray combustion and soot formation were investigated through UV-visible digital imaging and natural emission spectroscopy. Experiments were performed in a single cylinder high swirl compression ignition engine. The test engine was optically accessible and equipped with a common rail multi-jets injection system. Several injection pressures and timings at two EGR rates were tested. Digital imaging allowed characterizing the evaporating spray and the combustion process. UV-visible emission spectroscopy was used to follow the evolution of the combustion process chemical markers. Chemiluminescence signal due to OH was identified. The soot spectral feature in the visible wavelength range was correlated to soot engine out emissions. Conventional and optical data related to diesel fuel blended with gasoline and butanol were compared.

3

Diagnostyka optyczna kompozytów zawierających heterofulereny

Oźga K., Szota M., Nabiałek M., Dośpiał M., Rakus P., Kityk I. V.

Przetwórstwo Tworzyw

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2011

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[R.] 17, nr 6

488-492

PL

Eksperymentalnie ustalono, że zamieszczenie dwóch atomów germanu w cząsteczce C60 zwiększa podatność optyczną drugiego rzędu kompozytu polimerowego w porównaniu do podstawienia jednym atomem C59Ge. Efektywnymi dla takich kompozytów są metody badawcze oparte na fotoindukowanej drugiej harmonicznej światła SHG i absorpcji dwufotonowej, którą opisuje się tensorami czwartego rzędu i które nie wymagają niecentrosymetryczności badanego materiału. Poszczególne chromofory C59Ge i C58Ge2 (o stężeniu 7 % w j. wag.) wprowadzono do matrycy oligoeterakrylanu (OEA) i fotoutwierdzono światłem nadfioletowym. Jednocześnie dla takich kompozytów przeprowadzono obliczenia odpowiednich hiperpolaryzowalności i ustalano ich związek z podatnościami drugiego rzędu. Obliczenia teoretyczne dla cząsteczek C59Ge i C58Ge2 wprowadzonych do matrycy fotopolimerowej przeprowadzono metodami molekularnej optymalizacji geometrycznej struktury i dynamiki molekularnej. Zoptymalizowana struktura posłużyła do wyznaczenia hiperpolaryzowalności drugiego rzędu metodą chemii kwantowej.

EN

Using experimental methods it was established that replacement by the two germanium atoms in C60 molecule enhances the second order susceptibility of the polymer composites compared with a one-atom substitution C59Ge. More effective for the such composites are the methods based on the photoinduced second harmonic generation (SHG) and two-foton absorption (TPA) which are described by the fourth rank tensors and which do not need non-centrosymmetry. Different chromphores C59Ge and C58Ge2 (with a concentration of 7% in weight un.) were incorporated into the oligoetheracrylate (OEA) polymer matrix and solidification process was performed by using UV light. Simultaneously for such composites were performed the calculations of the corresponding hyperpolarizabilites and was established the relations with the susceptibilities of the second order. Theoretical calculations are performed using the molecular geometry optimization and molecular dynamics for the C59Ge and C58Ge2 molecules incorporated into the photopolymer matrix. This optimized molecular structure was used for the quantum chemical calculation of second-order hyperpolarisabilities.

4

Effect of butanol blend on in-cylinder combustion process. Part 1: Spark ignition engine

Tornatore C., Marchitto L., Mazzei A., Valentino G.

Journal of KONES

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2011

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Vol. 18, No. 2

427-438

EN

The addition of alcohol to conventional hydrocarbon fuels for a spark-ignition engine can increase the fuel octane rating and the power for a given engine displacement and compression ratio. In this work, the influence of butanol addition to gasoline in a port fuel-injection, spark ignition engine was investigated. The experiments were realized in a single cylinder ported fuel injection SI engine with an external boosting device. The optical accessible engine was equipped with the head of commercial SI turbocharged engine with the same geometrical specifications (bore, stroke, compression ratio) as the research engine. The effect on the spark ignition combustion process of 40% n-butanol blended in volume with gasoline was investigated by cycle resolved visualization. The engine worked at low speed, medium boosting and wide open throttle. Changes in spark timing and fuel injection phasing were considered in order to investigate normal and abnormal combustion. Comparisons between the parameters related to the flame luminosity and to the pressure signals were performed. The duration of injection for butanol blend was increased to obtain stoichiometric mixture. In open valve injection condition, the fuel deposits on intake manifold and piston surfaces decreased, allowing a reduction in fuel consumption. Butanol blend granted the performance levels of gasoline and in open valve injection allowed to minimize the abnormal combustion effects and the formation of ultrafine carbonaceous particles.

5

Effect of butanol blend on in-cylinder combustion process. Part 2: Compression ignition engine

Tornatore C., Marchitto L., Mazzei A., Valentino G., Corcione F. E., Merola S. S.

Journal of KONES

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2011

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Vol. 18, No. 3

473-483

EN

To meet the future stringent emission standards, innovative diesel engine technology, exhaust gas after-treatment, and clean alternative fuels are required. Oxygenated fuels showed tendency to decrease internal combustion engine emissions. In the same time, advanced fuel injection modes can promote further reduction in pollutants at the exhaust without penalty for the combustion efficiency. One of the more interesting solutions is provided by the premixed low temperature combustion (LTC) mechanism jointly to lower-cetane, higher-volatility fuels. In this paper, to understand the role played by these factors on soot formation, cycle resolved visualization, UV-visible optical imaging were applied in an optically accessed high swirl multi-jets compression ignition engine. Combustion tests were carried out using two fuels: commercial diesel and a blend of diesel with n-butanol. The fuels were tested at 70MPa injection pressure and different timings. At late injection timing coupled to high EGR rate (50%), the blends increased the ignition delay allowing operating in partially premixed LTC (PPLTC) regime in which the fuel is completely injected before the start of combustion. Strong reduction in engine out emissions of smoke and NOx were obtained with a little penalty on engine efficiency. This limitation was overcome operating at earlier injection timing in which a mixing controlled combustion (MCC) LTC regime was realized. In this regime, a good compromise between low engine out emissions and efficiency was achieved.

6

Optical diagnostics of the cyclic variation in the kernel development and abnormal combustion: SI boosted engine

Gallardo-Ruiz J. M., Ballais R., Merola S. S., Sementa P., Tornatore C.

Journal of KONES

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2010

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Vol. 17, No. 2

103-111

EN

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

7

Optical diagnostics of the cycle-to-cycle variation in the kernel development and abnormal combustion: SI small engine

Ballais, Gallardo-Ruiz J. M., Merola S. S., Sementa P., Tornatore C.

Journal of KONES

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2010

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Vol. 17, No. 2

17-25

EN

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.

8

Optical diagnostics in a spark ignition engine for two-wheel vehicles

Merola S. S., Sementa P., Tornatore C.

Journal of KONES

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2010

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Vol. 17, No. 4

323-336

EN

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.

9

New methods in optical diagnostics on production engines with only minor modifications

Hentschel W.

Silniki Spalinowe

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2009

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R. 48, nr 2

49-61

EN

The aim of this paper is to demonstrate the performance of micro-invasive optical diagnostics as advanced tools in the development process of modern direct-injection (DI) gasoline engines. The use of endoscopes and optical probes minimise the mechanical modifications on the engine necessary to achieve the optical access to the combustion chamber. No expensive optical engines with large optical windows are required but only small holes of about 10 mm in the cylinder head or in a plate between cylinder head and cylinder liner are used to apply laser diagnostics. Basic in-cylinder phenomena, such as the formation of the flow field, the penetration of the spray at high fuel pressure, the interaction of spray and flow, the formation of an ignitable mixture and the start of combustion are analysed in detail. High-power solid-state pulsed lasers emitting ultraviolet or green light, state-of the-art high-speed colour video cameras, and newly designed optical probes were used for the investigations. Selected results from current research and development work demonstrate the capability of micro-invasive techniques and pinpoint how the design of the combustion process benefits from these experimental investigations.

PL

Celem artykułu jest przedstawienie możliwości małoinwazyjnych metod diagnostyki optycznej jako zaawansowanych narzędzi w rozwoju nowoczesnych silników benzynowych z wtryskiem bezpośrednim (DI). Zastosowanie endoskopów i obserwacji optycznych minimalizuje konieczność mechanicznych modyfikacji w celu uzyskania dostępu optycznego do komory spalania. W takiej sytuacji nie jest konieczne wykorzystywanie kosztownych silników do specjalistycznych badań optycznych (tzw. silników transparentnych), wyposażonych w okna optyczne o dużych rozmiarach, lecz stosowane są jedynie otwory o niewielkiej średnicy, ok. 10 mm, w głowicy cylindrowej lub w płycie umieszczanej pomiędzy głowicą a tuleja do zastosowania diagnostyki laserowej. W ten sposób są szczegółowo analizowane podstawowe zjawiska w cylindrze, jak tworzenie się pola przepływów, rozprzestrzenianie się strugi paliwa przy dużym ciśnieniu wtrysku, wzajemne oddziaływanie pomiędzy strugą paliwa i przepływem czynnika, tworzenie się mieszanki zapłonowej na początku spalania. Do badań wykorzystuje się impulsowe lasery dużej mocy, promieniujące światłem ultrafioletowym lub zielonym na ciele stałym, współczesne kamery kolorowe do szybkiego filmowania i najnowszej konstrukcji sondy. Wybrane wyniki z aktualnych badań i prac rozwojowych wykazują przydatność małoinwazyjnych metod diagnostyki optycznej i wskazują, jak można wykorzystać badania optyczne przy projektowaniu procesu spalania.

10

Effect of the fuel injection splitting on the combustion process in a PFI boosted spark-ignition engine

Merola S. S., Sementa P., Tornatore C., Vaglieco B. M.

Journal of KONES

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2008

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Vol. 15, No. 4

331-339

EN

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.

11

Effect of the fuel injection pressure on the combustion process in a PFI boosted spark-ignition engine

Merola S. S., Sementa P., Tornatore C., Vaglieco B. M.

Journal of KONES

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2008

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Vol. 15, No. 4

341-349

EN

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.

12

Effect of fuel film deposition on combustion process in PFI SI engine

Merola S. S., Sementa P., Tornatore C., Vaglieco B. M.

Journal of KONES

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2007

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Vol. 14, No. 3

395-402

EN

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.