Rozprawy doktorskie: „Diesel ignition engine”

1

Wiseman, Marc William. "Spark ignition engine combustion process analysis". Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/11131/.

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Cylinder pressure analysis is widely used in the experimental investigation of combustion processes within gasoline engines. A pressure record can be processed to reveal detail of charge burning, which is a good indicator of combustion quality. The thesis describes the evaluation of an approximate technique for calculating the mass fraction of the charge that has burnt; a novel approach for determining heat loss to the block; the development of a powerful system for combustion analysis; and the investigation of the correlation between the crank angle location of the 50% mass burnt and minimum timing advance necessary to obtain the maximum engine torque. A detailed examination has been carried out into the uncertainties in the determination of the mass fraction burnt as suggested by Rassweiler and Withrow. A revised procedure has been developed which does not require a priori identification of the combustion end point, and a new approach is suggested to calculate the polytropic indices necessary for the pressure processing. This particular implementation of the analysis is able to identify late burning and misfiring cycles, and then take appropriate steps to ensure their proper analysis. The problems associated with the assumption of uniform pressure; alignment of the pressure changes to the volume changes; pressure sampling rate; clearance volume estimation; and calibrating the acquired pressure to absolute are also evaluated. A novel method is developed to ascertain, directly from the pressure history, the heat loss to the cylinder block. Both experimental and simulated data are used to support the accuracy of the suggested heat loss evaluation, and the sensitivity of the method to its inputs is examined. The conversion of procedures for combustion analysis into a format suitable for undertaking high speed analysis is described. The analysis techniques were implemented so that the engine can be considered to be on-line to the analysis system. The system was entitled Quikburn. This system can process an unlimited number of cycles at a particular running condition, updating the screen every 1.5 seconds. The analysis system has been used to study the potentially beneficial correlation between the location of the 50% mass burnt and MBT. The correlation is examined in detail, and found to be valid except under lean fueling conditions, which is seen to be caused by slow flame initiation. It is suggested that the optimum location of the 50% mass burnt can be used as a reference setting for the ignition timing, and as an indicator of combustion chamber performance. An engine simulation was employed to verify that changes in bum shape account for the small variation seen in the optimum 50% bum locations at different operating conditions of the engine. The bum shape changes also account for the range of optimum locations of the 50% mass burnt encountered in different engines.

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2

Newnham, S. K. C. "The combustion of ethanol in a spark-assisted diesel engine". Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/2157/.

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3

Norouzi, Shahrouz. "Interaction of diesel type fuels and engine fuel system components in compression ignition engines". Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5369/.

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Contact of fuels with engine components at low and elevated temperatures for various amounts of time is found to be challenging as this contact has several effects on engine fuel system components and fuels. Also, storage of fuels for a long period of time is found to have almost the same effect on both engine components and fuels upon engine use. In this thesis fuel and engine components’ contact have been studied for four typical metals used in the construction of many engine fuel systems; in form of pure or alloys (copper, aluminium, mild carbon steel and stainless steel), studied after contact with three of the currently available fuels for use in compression ignition engines. Ultra-low sulphur diesel fuel (ULSD) was used as the fossil fuel, rapeseed methyl ester (RME) as the first generation biofuel and finally gas-to-liquid (GTL) as the second generation of biofuel, obtained via the Fischer-Tropsch process. The investigation was performed in different sections: fuels and metals have been studied for any degradation after contact at low and high temperatures for short and long exposure times, and an understanding of the corrosion process and any degradation on both metals and fuels has been achieved; due to the high hygroscopic character of these fuels and the presence of possible impurities in the fuel, the investigation was extended for analysis of the effect of the presence or absence of absorbed water and dissolved air (in the form of Oxygen) in fuels on degradation and corrosion characteristics of these fuels.

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4

Russell, Brian Bailie. "Investigation of combustion systems for a two-stroke cycle diesel engine". Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317118.

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5

Oak, Sushil Shreekant. "Second law analysis of premixed compression ignition combustion in a diesel engine using a thermodynamic engine cycle simulation". Texas A&M University, 2008. http://hdl.handle.net/1969.1/86040.

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A second law analysis of compression ignition engine was completed using a thermodynamic engine cycle simulation. The major components of availability destruction and transfer for an entire engine cycle were identified and the influence of mode of combustion, injection timing and EGR on availability balance was evaluated. The simulation pressure data was matched with the available experimental pressure data gathered from the tests on the Isuzu 1.7 L direct injection diesel engine. Various input parameters of the simulation were changed to represent actual engine conditions. Availability destruction due to combustion decreases with advanced injection timing and under premixed compression ignition (PCI) modes; but it is found to be insensitive to the level of EGR. Similarly, trends (or lack of trends) in the other components of availability balance were identified for variation in injection timing, EGR level and mode of combustion. Optimum strategy for efficient combustion processes was proposed based on the observed trends.

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6

Chen, Xiang-Dong. "Measurement and modelling of diesel engine combustion with particular reference to soot formation". Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333281.

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7

Christodoulou, Fanos. "Hydrogen, nitrogen and syngas enriched diesel combustion". Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9109.

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On-board hydrogen and syngas production is considered as a transition solution from fossil fuel to hydrogen powered vehicles until problems associated with hydrogen infrastructure, distribution and storage are resolved. A hydrogen- or syngas-rich stream, which substitutes part of the main hydrocarbon fuel, can be produced by supplying diesel fuel in a fuel-reforming reactor, integrated within the exhaust pipe of a diesel engine. The primary aim of this project was to investigate the effects of intake air enrichment with product gas on the performance, combustion and emissions of a diesel engine. The novelty of this study was the utilisation of the dilution effect of the reformate, combined with replacement of part of the hydrocarbon fuel in the engine cylinder by either hydrogen or syngas. The experiments were performed using a fully instrumented, prototype 2.0 litre Ford HSDI diesel engine. The engine was tested in four different operating conditions, representative for light- and medium-duty diesel engines. The product gas was simulated by bottled gases, the composition of which resembled that of typical diesel reformer product gas. In each operating condition, the percentage of the bottled gases and the start of diesel injection were varied in order to find the optimum operating points. The results showed that when the intake air was enriched with hydrogen, smoke and CO emissions decreased at the expense of NOx. Supply of nitrogen-rich combustion air into the engine resulted in a reduction in NOx emissions; nevertheless, this technique had a detrimental effect on smoke and CO emissions. Under low-speed low-load operation, enrichment of the intake air with a mixture of hydrogen and nitrogen led to simultaneous reductions in NOx, smoke and CO emissions. Introduction of a mixture of syngas and nitrogen into the engine resulted in simultaneous reductions in NOx and smoke emissions over a wide range of the engine operating window. Admission of bottled gases into the engine had a negative impact on brake thermal efficiency. Although there are many papers in the literature dealing with the effects of intake air enrichment with separate hydrogen, syngas and nitrogen, no studies were found examining how a mixture composed of hydrogen and nitrogen or syngas and nitrogen would affect a diesel engine. Apart from making a significant contribution to existing knowledge, it is 3 believed that this research work will benefit the development of an engine-reformer system since the product gas is mainly composed of either a mixture of hydrogen and nitrogen or a mixture of syngas and nitrogen.

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8

Petersen, Ulf. "Jet mixing in DI diesel engine combustion chamber model under quiescent and swirling conditions". Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306381.

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9

Fang, Ming. "Analysis of Variability and Injection Optimization of a Compression Ignition Engine". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250532113.

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10

Bech, Alexander. "Thermal analysis and fuel economy benefits of cylinder deactivation on a 1.0l spark ignition engine". Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49777/.

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The deactivation of a cylinder on a 1.0litre three cylinder turbocharged gasoline engine has been investigated providing novel information on thermal and fuel consumption effects associated with the technology. This comes in light of providing solutions to reduce fuel consumption and CO2 emissions resulting from internal combustion engines. The investigation has been carried out through the PROgram for Modelling of Engine Thermal Systems (PROMETS). A version of PROMETS was extensively developed to characterise a commercially produced TCE not fitted with cylinder deactivation technology. Developments include an improved gas-side heat transfer expression to account for increased heat transfer to coolant due to the addition of an integrated exhaust manifold; addition of an expression to represent natural convection to model heating of quiescent coolant in the block; and a method to estimate the boosted intake manifold pressure past the throttle due to turbocharging on a gasoline engine. The 0-D approach used in this thesis compared to higher resolution computational tools has allowed for thermal and performance predictions to be made within a couple of minutes compared to several hours or days. In effect, PROMETS has been a time and cost effective tool during the development stages of a prototype engine. The PROMETS model indicated that no adverse changes in engine thermal behaviour arose with cylinder deactivation. The largest temperature change of < 400 occurs in the exhaust valve lower stem for the deactivated cylinder. Temperature changes in other components throughout the engine are an order of magnitude smaller. Although the largest temperature differences between the deactivated and firing cylinders were found to be in the range of < 70 , these remain within normal engine operating temperatures of < 100 . Also, by on-setting deactivation past an oil temperature of 40 , warm-up times were marginally extended compared to operation on all cylinders from key-on. Experimental inputs representing changes in engine gross indicated thermal efficiency and the work loss associated with the motoring of a piston complemented modelling work in predicting fuel consumption changes due to deactivation. Reductions in pumping losses account for the majority of the fuel consumption benefit associated with deactivating a cylinder. The main limitation in the employment of cylinder deactivation stems from the deterioration in the gross indicated thermal efficiency. Modelled results show that fuel consumption improvements are highest on low and part load operation envelopes. As such over the NEDC and FTP-75 benefits are in the range of 3.5%. Applying the technology over dynamically loaded cycles such as the WLTC and ARTEMIS, results in benefits of less than 1.6%. Further to modelling work on cylinder deactivation, experimental work has been carried out with the aim of allowing any engine size to be tested to cover transient drive cycles for future research. Future research could be in the aim of investigating technologies to reduce CO2 and emissions resulting from ICEs. Results show that the control solution implemented has allowed eddy-current dynamometers normally used for constant speed and brake load conditions to operate cycles such as the WLTC or any transient brake torque and engine speed pattern. Benchmark fuel consumption values for two engines of differing swept volume are within a 4g error band equivalent to a 0.36% and 0.67% percentage error band demonstrating the excellence of the control system.

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11

Laforet, Christopher A. "Combustion of natural gas with entrained diesel in a heavy-duty compression-ignition engine". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/17010.

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High-pressure direct-injection of natural gas for use in compression-ignition engines has been found to reduce emissions without sacrificing performance relative to pure diesel operation. In the present work, prototype ‘co-injectors’ which inject a diesel and natural gas mixture from a single injector were tested in a heavy-duty, 6-cylinder Cummins ISX engine with 5 cylinders disabled. One prototype (‘B’) was tested under low-speed, low-load conditions, to determine the effects of fuel flows and in-cylinder conditions on the combustion characteristics of co-injection. Co-injector B, and a second prototype (Co-injector CS: A variation of Co-injector B which mixes the fuels differently) were tested at three engine modes using two injections per cycle to determine the effect of the duration of the first injection on emissions and combustion characteristics. The performance of the co-injectors was compared to Westport Innovation’s High Pressure Direct Injection (HPDI) J36 injector to determine if co-injection can produce comparable emissions. Single injection tests carried out with Co-injector B at 800 RPM over a range of diesel flows, gas flows, injection pressures, and cylinder temperatures & pressures were used to generate response surfaces for knock intensity, ignition delay, and combustion efficiency. It was found that diesel flow and the cylinder pressure at the time of injection had the largest effect of knock intensity and ignition delay, and that the knock/ignition delay relationship in co-injection is inverse. The double injection tests showed that the difference in diesel distributions within the gas plenums of CS and B results in more diesel being injected during the first injection in CS compared to B, which supports previous results. It was found that short first pulses resulted in the lowest emissions for both co-injectors, and that with low first gas pulse widths the performance of the co-injectors is comparable to that of Westport’s HPDI-J36 injector.

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12

Reiter, Aaron Jesse. "Combustion and emissions characteristics of a compression-ignition engine using dual ammonia-diesel fuel". [Ames, Iowa : Iowa State University], 2009.

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13

Thoo, Wei Jet. "A study of the ignition delay characteristics of combustion in a compression ignition engine operating on blended mixtures of diesel and gasoline". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32843/.

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The interest to study diesel-gasoline fuel mix for CI engine combustion had been motivated by the higher thermal efficiency of CI engine compared to SI engine which gasoline normally runs in and the report of having lower NOx and PM emissions for gasoline combustion in CI engine. The experimental CI engine was unable to run on 100% gasoline but able to run on gasoline blend as high as G80 with default SOI timing setting. 100% gasoline would not run despite it contains only 20% more gasoline than G80 due to its extremely longer ignition delay caused by the exponential increase of gasoline blend’s ID. Engine brake thermal efficiencies of all gasoline blends tested up to G80 were comparable and averaged at 24.2%, 33.8% and 39.8% for engine speed-load conditions of 2000rev/min 2.5bar BMEP, 2000rev/min 5bar BMEP and 2000rev/min 8.5bar BMEP, accordingly. This finding confirmed that gasoline blend could be a new alternative fuel that offers comparable performance to the liquid fuel market for CI engine. In Europe, diesel blended with a small percentage of biodiesel or ethanol has been common to liquid fuel market. The study focused on ID that was closely correlated to NOx and soot formations in engine cylinder instead of NOx and PM emissions at tailpipe. The longer ID of 100% gasoline in relative to diesel could go up to 14CAD resulted in increased proportion of premixed combustion to mixing-controlled combustion at the rate of 40 Joule per CAD increase in ID. This incremental premixed combustion proportion was ideal for low NOx and soot formations in CI engine. ID was able to be discriminated into physical delay, a period dictated by engine speed-load conditions and controlled fuel breakup, fuel vaporisation and fuel-air mixing; and chemical delay, a period dictated by fuel chemical kinetic mechanism and controlled the amount of heat released. This finding gave valuable insight to the fact that proportion of premixed combustion and mixing-controlled combustion were controlled by chemical delay. Zero-dimensional theoretical combustion study with chemical kinetic mechanism confirmed that the exponential increased ID trend of gasoline blends was attributed to chemical delay. Hence a gasoline blend close to 100% gasoline would have very lean premixed combustion and small mixing-combustion which correlated to very low NOx and soot formations in cylinder. In order to understand the NOx and soot formations in cylinder in detail, a 73species reduced chemical kinetic mechanism that could represent gasoline blend combustion in CFD was developed. This reduced chemical kinetic mechanism could be used for future CFD work to understand effect of interactions between physical processes (fuel breakup, fuel vaporisation and fuel-air mixing) and chemical processes (activation of fuel combustion chemistry) on NOx and soot formations in cylinder. This work founded an effective semi-automatic reduction methodology with MATLAB algorithms for developing the 73species CFD-compatible reduced chemical kinetic mechanism of gasoline blends. This platform made building a surrogate fuel’s reduced chemical kinetic mechanism from multiple detailed chemical kinetic mechanisms of single component fuels fast, accessible and friendly to users of all background. DRG reduction technique had been enhanced by the multiple-stage ROP and multiple-step DRG approaches. The multiple-stage ROP and multiple-step approaches increased the species size reduction of chemical kinetic mechanisms by additional 8% and 13.5%, accordingly. The additional species size reduction capability of both approaches would be beneficial for the reduction of chemical kinetic mechanism for CFD use which is practically limited to size of 100species for feasible computational errors and speed. Apart from the limitation for the percentage of gasoline blend that could be used in the experimental CI engine, the lower compressibility of gasoline blends in relative to diesel had caused the SOI timing to be retarded up to 3CAD in this pump-triggered type of injection system. This shift of combustion phase had no significant effect on the ID and heat-release characteristics. The combustion phase shift can be easily compensated by advancing the SOI accordingly.

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14

Shoukry, Ehab F. "Numerical simulation for parametric study of a two-stroke compression ignition direct injection linear engine". Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3071.

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Thesis (Ph. D.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains xxvii, 166 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 121-126).

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15

Rahman, S. M. Ashrafur. "Experimental investigation of essential oils in a diesel engine". Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/121763/2/__qut.edu.au_Documents_StaffHome_StaffGroupH%24_halla_Desktop_S.%20M.%20Ashrafur%20Rahman%20Thesis.pdf.

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The potential use of waste stream essential oils were evaluated as fuel supplements for diesel vehicle/machinery used by producers of these oils. Orange, eucalyptus and tea tree oils were selected; which are native to and/or extensively cultivated throughout Australia. These essential oils are mainly used in the medical and natural therapy sector as well as fragrance and flavouring industry. The high quality of the final product leads to a significant very low value waste stream. Engine performance and emissions evaluation showed that essential oils are comparable to diesel fuel. Their use will help to reduce diesel dependency and fuel costs.

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16

Weall, Adam James. "Characteristics of partially-premixed compression-ignition combustion using diesel, biodiesel and gasoline in a multi-cylinder direct-injection diesel engine". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608565.

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17

Brown, Benjamin Scott. "High-pressure direct-injection of natural gas with entrained diesel into a compression-ignition engine". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5155.

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The high-pressure direct-injection (HPDI) of natural gas in a compression ignition engine has the potential to reduce demand for petroleum derived fuels and significantly reduce the level of pollutants and greenhouse gases emitted from heavy duty transport vehicles. A new HPDI injector was tested where diesel is injected into a gas/diesel reservoir in the injector and the diesel and gas are then co-injected into the combustion chamber. In order to identify interactions between the diesel and gas in the reservoir, two different injector geometries were tested: prototypes A and B. Prototype B had reduced reservoir volume to increase gas velocity inside the injector. A majority of the tests were conducted in a single-cylinder test engine derived from a Cummins ISX diesel engine. As prototype A was being modified to create Prototype B this test engine was moved to a larger test cell. After updating the electrical, mechanical, and safety systems, the test engine in the new test cell was found to run repeatably; however, emissions comparisons between both test cells was not possible due to different analyzers being used. Single gas and double gas injections were conducted for both injector prototypes. The single gas injection tests found that increasing the diesel injection mass reduced the mass of gas injected. Increased diesel injection mass also shortened ignition delay, reduced unburned and partially burned fuel and increased NOx emissions. Holding the diesel injection mass constant and reducing the gas injection mass had the same effect as increasing diesel on ignition delay and gaseous emissions. If the diesel injection mass was kept constant and a second gas injection was added, the heat release due to the first injection decreased and the start of combustion was retarded. This appears to have occurred because some of the diesel was carried into the cylinder by the second injection and less diesel was available in the first injection to promote ignition. Double gas injection tests were conducted where the load, speed, and combustion timing were controlled in order to determine how injector operation affects parameters such as knock intensity, and gaseous emissions. At lower diesel injection masses, retarded combustion timing led to shorter ignition delays and less intense knock and lower unburned fuel emissions at lower loads. Longer relative times between the diesel and gas injections had a similar effect as lower diesel injection mass, especially at advanced combustion timing. For these tests Prototype B exhibited shorter ignition delays but higher knock intensities than Prototype A.

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18

Aksu, Cagdas. "Performance Analysis Of A Compression Ignition Internal Combustion Engine Using Superheated Ethanol Vapor". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613255/index.pdf.

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The aim of this study is to experimentally measure performance characteristics of a compression ignition (CI) internal combustion engine using superheated ethanol vapor. The engine is a 1.3L inline 4 cylinder direct injection (DI) turbocharged compression ignition (CI) engine. While the engine will be fed with superheated ethanol as homogeneous fuel-air mixture through intake manifold, the amount of diesel fuel that the engine requires to run at idle will also be supplied in order to initiate combustion. Ethanol will be superheated using a new patented double heat exchanger has been manufactured by Prof. Dr. Demir Bayka, Dr. Anil Karel and Deniz Ç
akar. The results will indicate if the suggested concept can be applicable.

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19

Whitelaw, David Stuart. "Droplet atomisation of Newtonian and non-Newtonian fluids including automotive fuels". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266620.

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20

Salt, Thomas A. "Evaluation of the Benefits of Oxy-combustion on Emissions from a Compression Ignition Engine". Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2957.pdf.

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21

Estepa, Ruiz Daniel. "Study of different fuel injection and air management strategies as a tool for emissions control in a compression ignition engine (Diesel engine)". Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/113076.

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En la actualidad, la industria del transporte es la encargada de satisfacer las necesidades logísticas del mundo. Los combustibles fósiles continúan siendo la principal fuente de energía de esta industria, y el motor Diésel, una de las tecnologías principales en la transformación de la energía química de estos combustibles en energía mecánica a través del proceso de combustión. Asociado a este proceso de transformación de la energía, un conjunto de efectos indeseados como las emisiones contaminantes o los gases de efecto invernadero han hecho movilizar a la comunidad científica. Dicha comunidad, ha realizado importantes esfuerzos en la investigación de soluciones limpias y eficientes que ayuden a minimizar los efectos indeseados del uso del motor Diésel. Sumado a los esfuerzos en la investigación, diferentes organizaciones gubernamentales han generado normativas que regulan estas emisiones contaminantes y la industria del motor ha reaccionado integrando soluciones tecnológicas que han hecho evolucionar la configuración original del motor Diésel. Debido a razones principalmente geopolíticas, el desarrollo económico a nivel mundial no se ha dado de manera homogénea, y en la actualidad, existe una disparidad global en cuanto a las exigencias en normativa de emisiones y la implementación de tecnologías para su control, siendo estas afectadas principalmente por sus costos. Es en este contexto donde se enmarca esta tesis doctoral, cuyo objetivo principal es el estudio de diferentes estrategias de inyección y de renovación de la carga como herramienta de control de emisiones en motores de encendido por compresión, teniendo en cuenta el costo de su integración. Se busca poder definir los límites de estas estrategias de bajo costo, determinando así su potencial real en la futura normativa de los mercados emergentes. Para abordar dicho objetivo, la tesis se ha desarrollado en tres etapas. En la primera, se ha realizado una aproximación teórico-experimental a las estrategias de inyección mediante modelado 3D-CFD y ensayos paramétricos en motor que permiten establecer como los parámetros de inyección responden al objetivo planteado. En la segunda etapa, se han estudiado las estrategias de renovación de la carga. Primero desde el modelado 1D para luego su posterior evaluación mediante su ensayo experimental en motor definiendo de esta manera las ventajas e inconvenientes de cada estrategia. En la tercera y última etapa, se han combinado todas las estrategias previamente estudiadas desde una aproximación experimental. De esta manera se puede alcanzar el objetivo de la tesis doctoral donde se ha comprobado la viabilidad de estas estrategias de bajo costo y se ha determinado su verdadero potencial como herramientas de control de las emisiones contaminantes.
En l'actualitat, la indústria del transport és l'encarregada de satisfer les necessitats logístiques del món. Els combustibles fòssils continuen sent la principal font d'energia d'aquesta indústria, i el motor Diésel, una de les tecnologies principals en la transformació de l'energia química d'aquests combustibles en energia mecànica a través del procés de combustió. Associat a aquest procés de transformació de l'energia, un conjunt d'efectes indesitjats com les emissions contaminants o els gasos d'efecte hivernacle han fet mobilitzar a la comunitat científica. Aquesta comunitat, ha realitzat importants esforços en la recerca de solucions netes i eficients que ajuden a minimitzar els efectes indesitjats de l'ús del motor Diésel. Sumat als esforços en la recerca, diferents organitzacions governamentals han generat normatives que regulen aquestes emissions contaminants i la indústria del motor ha reaccionat integrant solucions tecnològiques que han fet evolucionar la configuració original del motor Diésel. A causa de raons principalment geopolítiques, el desenvolupament econòmic a nivell mundial no s'ha donat de manera homogènia, i en l'actualitat, existeix una disparitat global quant a les exigències en normativa d'emissions i la implementació de tecnologies per al seu control, sent aquestes afectades principalment pels seus costos. És en aquest context on s'emmarca aquesta tesi doctoral, que el seu objectiu principal és l'estudi de diferents estratègies d'injecció i de renovació de la càrrega com a eina de control d'emissions en motors d'encès per compressió, tenint en compte el cost de la seua integració. Se cerca poder definir els límits d'aquestes estratègies de baix cost, determinant així el seu potencial real en la futura normativa dels mercats emergents. Per a abordar dita objectiva, la tesi s'ha desenvolupat en tres etapes. En la primera, s'ha realitzat una aproximació teòric-experimental a les estratègies d'injecció mitjançant modelatge 3D-CFD i assajos paramètrics en motor que permeten establir com els paràmetres d'injecció responen a l'objectiu plantejat. En la segona etapa, s'han estudiat les estratègies de renovació de la càrrega. Primer des del modelatge 1D per a després la seua posterior avaluació mitjançant el seu assaig experimental en motor definint d'aquesta manera els avantatges i inconvenients de cada estratègia. En la tercera i última etapa, s'han combinat totes les estratègies prèviament estudiades des d'una aproximació experimental. D'aquesta manera es pot aconseguir l'objectiu de la tesi doctoral on s'ha comprovat la viabilitat d'aquestes estratègies de baix cost i s'ha determinat el seu vertader potencial com a eines de control de les emissions contaminants.
Nowadays, the transport industry is responsible for accomplish the world's logistics requirements. Fossil fuels continue to be the main source of energy for this industry, and the Diesel engine, one of the main technologies in the transformation of the chemical energy of these fuels into mechanical energy through combustion. Associated with this process of energy transformation, a set of undesired effects such as pollutant emissions or greenhouse gases have challenged the scientific community that has made significant research efforts aiming clean and efficient solutions. Added to the scientific community efforts, different governmental organizations have created regulations in order to control these pollutant emissions and the engine industry has reacted by integrating technological solutions that have evolved the original configuration of the Diesel engine. Due mainly to geopolitical reasons, economic development worldwide has not occurred in a homogeneous manner, and currently, there is a global disparity regarding the requirements in emission regulations and the implementation of technologies for their control, mainly driven by their costs. It is in this framework where is set this doctoral thesis, with the main objective to study different injection and air management strategies as a tool for emission control in compression ignition engines, taking into account the cost of their integration. The aim is to be able to define the limits of these low-cost strategies, thus determining their real potential in the future regulations of emerging markets. To address this objective, the thesis has been developed in three stages. In the first one, a theoretical-experimental approach to the injection strategies has been carried out using 3D-CFD modeling and parametric engine tests which allow us to establish how the injection parameters help to reach the depicted thesis objective. In the second stage, the air management strategies have been studied. First, from the 1D modeling point of view in order to select the best option for this platform, and later to proceed with the experimental validation of this selection. Through the described approach is possible defining the advantages and disadvantages of each air management strategy. In the third and final stage, all previously studied strategies have been combined from an experimental approach. In this way, the evaluation of these cost-effective strategies has been defined and the fully potential as a tool for emissions control has been determined thus the objective of the doctoral thesis could be achieved.
Estepa Ruiz, D. (2018). Study of different fuel injection and air management strategies as a tool for emissions control in a compression ignition engine (Diesel engine) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113076
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Abuhabaya, Abdullah. "Investigation of engine performance and exhaust gas emissions by using bio-diesel in compression ignition engine and optimisation of bio-diesel production from feedstock by using response surface methodology". Thesis, University of Huddersfield, 2012. http://eprints.hud.ac.uk/id/eprint/14064/.

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Bio-diesel, derived from the transesterification of vegetable oils or animal fats with simple alcohols, has attracted more and more attention recently. As a cleaner burning diesel alternative, bio-diesel claims to have many attractive features including: biodegradability, nontoxicity, renewability and low emission profiles. Free fatty acid (FFA) esterification and triglyceride (TG) transesterification with low alcohols molar ratio are the central reactions for the bio-diesel production. This study presents an experimental investigation into the effects of running biodiesel fuel and its blends on conventional diesel engines. Bio-fuels provide a way to produce fuels without redesigning any of the engine technology present today, yet allowing for green house emissions to decrease. Bio-diesel is one of these types of emerging bio-fuels, which has an immediate alternative fuel, while providing a decrease in green house gas emissions, as well as a solution to recycling used Waste Vegetable Oils which are otherwise disposed. This study shows how by blending bio-diesel with petroleum diesel at intervals of B5, B10, B15, and B20 decrease green house gas emissions significantly while maintaining similar performance output and efficiency with respect to 100% petroleum diesel. The focus of this research is to optimize the biodiesel production from crude sunflower oil. The effect of variables including methanol/oil molar ratio, NaOH catalyst concentration, reaction time, reaction temperature, and rate of mixing on the bio-diesel yield was examined and optimized by response surface methodology (RSM). Besides, a second-order model was deduced to predict the biodiesel yield. Confirmation experiment was further conducted, validating the efficacy of the model. Transesterification of sunflower oil was carried out using low molecular weight alcohols and sodium hydroxide. For sunflower oil, a central composite design with eight factorial, six center and six axial points was used to study the effect of catalyst concentration, molar ratio of methanol to sunflower oil and reaction temperature on percentage yield of the biodiesel. Catalyst concentration and molar ratio of methanol to sunflower oil were the most influential variables affecting percentage conversion and percentage initial absorbance. Maximum percentage yield of 95 % is predicted at a catalyst concentration of 1.1 % (wt/wt) and methanol to sunflower oil molar ratio of 6.8:1 at reaction time of 66 min and temperature of 35°C. In general, the sunflower oil biodiesel exhibited friendly environmental benefits and acceptable stability, demonstrating its feasibility as an alternative fuel.

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Abate, Vito J. "Natural gas ignition delay study under diesel engine conditions in a combustion bomb with glow plug assist". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58696.pdf.

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Zhao, Ming [Verfasser], i Sebastian [Akademischer Betreuer] Kaiser. "Optical diagnostics for spray, ignition, and combustion in a light-duty Diesel engine / Ming Zhao ; Betreuer: Sebastian Kaiser". Duisburg, 2020. http://d-nb.info/1213245540/34.

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PIANO, ANDREA. "Analysis of Advanced Air and Fuel Management Systems for Future Automotive Diesel Engine Generations". Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2709586.

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The increasing stringency of pollutant emissions regulations, aiming to fuel neutral NOx limits, is expected to foster the implementation of new technologies in terms of aftertreatment, air management and fuel injection systems. In this field, modern diesel engines are equipped with electronically-controlled flexible fuel injection systems and air/gas/EGR control valves. The only part in the air system ‘left for revolutionary’ is the valvetrain and a fully flexible Variable Valve Actuation (VVA) is becoming nowadays highly desirable for modern diesel engine. In this context, the purpose of the research activity was, on one hand, to evaluate and identify, through numerical simulation, the best VVA strategies to be implemented in a passenger car diesel engine by quantifying and choosing benefits vs drawbacks of VVA strategies. On the other hand, the definition of the best injection pattern for BSFC, Emission and NVH improvements through the adoption of Genetic Algorithm was performed. The EURO VI medium diesel engine (1.6 l 4L) developed by General Motors Global Propulsion Systems was selected as case study.

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Ghomashi, Hossein. "Modelling the combustion in a dual fuel HCCI engine : investigation of knock, compression ratio, equivalence ratio and timing in a Homogeneous Charge Compression Ignition (HCCI) engine with natural gas and diesel fuels using modelling and simulation". Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7344.

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This thesis is about modelling of the combustion and emissions of dual fuel HCCI engines for design of “engine combustion system”. For modelling the combustion first the laminar flamelet model and a hybrid Lagrangian / Eulerian method are developed and implemented to provide a framework for incorporating detailed chemical kinetics. This model can be applied to an engine for the validation of the chemical kinetic mechanism. The chemical kinetics, reaction rates and their equations lead to a certain formula for which the coefficients can be obtained from different sources, such as NASA polynomials [1]. This is followed by study of the simulation results and significant findings. Finally, for investigation of the knock phenomenon some characteristics such as compression ratio, fuel equivalence ratio, spark timing and their effects on the performance of an engine are examined and discussed. The OH radical concentration (which is the main factor for production of knock) is evaluated with regard to adjustment of the above mentioned characteristic parameters. In the second part of this work the specification of the sample engine is given and the results obtained from simulation are compared with experimental results for this sample engine, in order to validate the method applied in AVL Fire software. This method is used to investigate and optimize the effects of parameters such as inlet temperature, fuels ratio, diesel fuel injection timing, engine RPM and EGR on combustion in a dual fuel HCCI engine. For modelling the dual fuel HCCI engine AVL FIRE software is applied to simulate the combustion and study the optimization of a combustion chamber design. The findings for the dual fuel HCCI engine show that the mixture of methane and diesel fuel has a great influence on an engine's power and emissions. Inlet air temperature has also a significant role in the start of combustion so that inlet temperature is a factor in auto-ignition. With an increase of methane fuel, the burning process will be more rapid and oxidation becomes more complete. As a result, the amounts of CO and HC emissions decrease remarkably. With an increase of premixed ratio beyond a certain amount, NOX emissions decrease. With pressure increases markedly and at high RPM, knock phenomenon is observed in HCCI combustion.

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Monsalve, Serrano Javier. "Dual-fuel compression ignition: towards clean, highly efficient combustion". Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/75109.

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The more and more stringent emissions regulations, together with the greater fuel economy demanded by vehicle users, impose a clear objective to researchers and engine manufacturers: look for the maximum efficiency with the minimum pollutant emissions levels. The conventional diesel combustion is a highly efficient process, but also leads to high levels of NOx and soot emissions that require using aftertreatment systems to reduce the final levels released to the environment. Since these systems incur in higher costs of acquisition and operation of the engine, the scientific community is working on developing alternative strategies to reduce the generation of these pollutants during the combustion process itself. The literature shows that the new combustion modes based on promoting low temperatures during this process, offer high efficiency and very low NOx and soot levels simultaneously. However, after years of investigation, it can be concluded that these techniques cannot be applied in the whole engine operating range due to, among others, factors like the low control of the combustion process. In recent years, it has been demonstrated that the dual-fuel combustion technique allows to overcome this limitation thanks to the additional degree of freedom provided by the capacity of modulating the fuel reactivity depending on the engine operating conditions. This characteristic, together with the near-zero NOx and soot levels obtained with this technique, has encouraged the scientific community to deeply investigate the dual-fuel combustion. In this sense, former works confirm the advantages previously described, concluding that still exist some limitations to be tackled, as well as some margin for improving the potential of this combustion concept. The general objective of the present Doctoral Thesis is to contribute to the understanding of the dual-fuel combustion mode, with the particular aim of exploring different ways to improve its efficiency. For this purpose, it has been experimentally evaluated different options such as the modification of the engine operating parameters, specific designs of the piston geometry or the use of alternative fuels. With the aim of answering some of the questions found in the literature, the first part of each study has been dedicated to perform a detailed analysis of the influence of each particular strategy on the dual-fuel operation at low load. Later, it has been checked the ability of each option to extend the dual-fuel operating range towards higher engine loads. It is interesting to note that the analysis of some results has been supported by CFD calculations, which have allowed to understand some local phenomena occurring during the dual-fuel combustion process, which cannot be confirmed only from the experimental point of view. Finally, taking into account the knowledge acquired during the different studies performed, the last chapter of results has been devoted to evaluate the ability of the dual-fuel concept to operate over the whole engine map, as well as to identify the possible limitations that this technique presents from the technological point of view.
Las cada vez más restrictivas normativas anticontaminantes, junto con la demanda de motores con menor consumo de combustible por parte de los usuarios, imponen un claro objetivo a investigadores y fabricantes de motores: la búsqueda de la máxima eficiencia con los mínimos niveles de emisiones contaminantes. La combustión diésel convencional ofrece una alta eficiencia, pero a su vez da lugar a elevadas emisiones de NOx y hollín que requieren del uso de sistemas de postratamiento para reducir los niveles finales emitidos al ambiente. Dado que estos sistemas incurren en mayores costes de adquisición y operación del motor, la comunidad científica está trabajando en el desarrollo distintas estrategias para reducir la generación de estos contaminantes durante el propio proceso de combustión. La literatura demuestra que los nuevos modos de combustión basados en promover bajas temperaturas durante este proceso, ofrecen simultáneamente una elevada eficiencia y muy bajos niveles de NOx y hollín. Sin embargo, tras años de investigación, se puede llegar a la conclusión de que estas técnicas no pueden ser aplicadas en todo el rango de operación del motor debido a, entre otros, factores como el escaso control sobre el proceso de combustión. En los últimos años, se ha demostrado que la técnica de combustión dual-fuel permite superar esta limitación gracias al grado de libertad adicional que supone la capacidad de modular la reactividad del combustible en función de las condiciones de operación del motor. Esta característica, junto con los casi nulos niveles de NOx y hollín que proporciona, ha despertado un gran interés sobre la comunidad científica. En este sentido, trabajos precedentes confirman las ventajas que este modo de combustión ofrece, demostrando a su vez que aún existen una serie de limitaciones por abordar, así como cierto margen por explotar para mejorar el potencial de este concepto. La presente Tesis Doctoral plantea como objetivo general el contribuir a la comprensión del modo de combustión dual-fuel, y de manera particular explorar distintas vías con objeto de mejorar su eficiencia. Para ello, se han evaluado de manera experimental diferentes opciones que van desde la modificación de los parámetros de operación del motor, hasta diseños específicos de la geometría del pistón o el uso de combustibles alternativos. Tratando de responder algunas de las cuestiones encontradas en la literatura, en cada uno de los estudios se ha realizado un análisis detallado de la influencia del parámetro en cuestión sobre la operación del motor a baja carga, y a su vez se ha comprobado la capacidad de cada una de estas opciones de extender la operación del motor hacia cargas más elevadas. Cabe destacar que el análisis de ciertos resultados se ha apoyado en cálculos numéricos CFD, los cuales han permitido entender ciertos fenómenos locales que ocurren durante el proceso de combustión dual-fuel, y que no pueden ser confirmados únicamente desde el punto de vista experimental. Finalmente, teniendo en cuenta el conocimiento adquirido en los diferentes estudios realizados, el último capítulo de resultados se ha dedicado a evaluar la capacidad de operación del concepto dual-fuel en todo el rango de funcionamiento del motor, así como a identificar las posibles limitaciones que esta técnica presenta desde el punto de vista tecnológico.
Les cada vegada més restrictives normatives anticontaminants, juntament amb la demanda de motors amb menor consum de combustible per part dels usuaris, imposen un clar objectiu a investigadors i fabricants de motors: la cerca de la màxima eficiència amb els mínims nivells d'emissions contaminants. La combustió dièsel convencional ofereix una alta eficiència, però al seu torn dóna lloc a elevades emissions de NOx i sutge que requereixen de l'ús de sistemes de postractament per a reduir els nivells finals emesos a l'ambient. Aquests sistemes incorren en majors costos d'adquisició i operació del motor, per la qual cosa de forma paral·lela, la comunitat científica està treballant en el desenvolupament de diferents estratègies per a reduir la generació d'aquests contaminants durant el propi procés de combustió. La literatura demostra que les noves tècniques de combustió basades a promoure baixes temperatures durant aquest procés, ofereixen simultàniament una elevada eficiència i molt baixos nivells de NOx i sutge. No obstant açò, després d'anys de recerca, es pot arribar a la conclusió que aquestes tècniques no poden ser aplicades en tot el rang d'operació del motor a causa de, entre uns altres, factors com l'escàs control sobre el procés de combustió. En els últims anys, s'ha demostrat que la tècnica de combustió dual-fuel permet superar aquesta limitació gràcies al grau de llibertat addicional que suposa la capacitat de modular la reactivitat del combustible en funció de les condicions d'operació del motor. Aquesta característica, juntament amb els quasi nuls nivells de NOx i sutge que proporciona, ha despertat un gran interès sobre la comunitat científica. En aquest sentit, treballs precedents confirmen els avantatges que aquesta tècnica de combustió ofereix, demostrant al seu torn que encara existeixen una sèrie de limitacions per abordar, així com cert marge per explotar per a millorar el potencial d'aquest concepte. La present Tesi Doctoral planteja com a objectiu general el contribuir a la comprensió de la tècnica de combustió dual-fuel, i de manera particular explorar diferents vies a fi de millorar la seua eficiència. Per a açò, s'han avaluat de manera experimental diferents opcions que van des de la modificació dels paràmetres d'operació del motor, fins a dissenys específics de la geometria del pistó o l'ús de combustibles alternatius. Tractant de respondre algunes de les qüestions trobades en la literatura, en cadascun dels estudis s'ha realitzat una anàlisi detallada de la influència del paràmetre en qüestió sobre l'operació del motor a baixa càrrega, i al seu torn s'ha comprovat la capacitat de cadascuna d'aquestes opcions d'estendre l'operació del motor cap a càrregues més elevades. Cal destacar que l'anàlisi de certs resultats s'ha recolzat en càlculs numèrics CFD, els quals han permès entendre certs fenòmens locals que ocorren durant el procés de combustió dual-fuel, i que no poden ser confirmats únicament des del punt de vista experimental. Finalment, tenint en compte el coneixement adquirit en els diferents estudis realitzats, l'últim capítol de resultats s'ha dedicat a avaluar la capacitat d'operació del concepte dual-fuel en tot el rang de funcionament del motor, així com a identificar les possibles limitacions que aquesta tècnica presenta des del punt de vista tecnològic.
Monsalve Serrano, J. (2016). Dual-fuel compression ignition: towards clean, highly efficient combustion [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/75109
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Pak, Sun. "Adaptation, combustion et limites pauvres d'un moteur à allumage commandé au gaz naturel obtenu par conversion d'un diesel faible puissance". Valenciennes, 1994. https://ged.uphf.fr/nuxeo/site/esupversions/1d663861-db36-4829-9d80-aa7826a05ebe.

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Un moteur diesel faible puissance a était converti en A. C. Puis alimenté au gaz naturel. Les caractéristiques générales de la combustion (délais, durées de combustion, dispersion cyclique) ont été étudiées en fonction du rapport air-gaz, de l'avance à l'allumage, et du type de bougie ainsi que les performances du moteur. Pour le comportement en mélange très pauvre, nous avons déterminé les limites opératoires, analyse le déroulement de la combustion et observe les variations de pression. En utilisant un générateur de turbulence en forme de cône, nous avons reculé les limites pauvres et réduit la dispersion cyclique et la pollution estimée en fonction de la richesse du mélange, de l'avance à l'allumage, de la vitesse et de la charge du moteur. A la fin de l'étude, nous donnons les conditions opératoires optimum pour différentes charges et vitesses.

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Paolucci, Lorenzo. "High efficiency low temperature combustion in compression ignition engines for automotive and aeronautical applications". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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Internal combustion engines are increasingly subject to ever more stringent and severe Euro-legislations about pollutants emissions in terms of nitrogen oxide, carbon monoxide, unburned hydrocarbons and soot. In last years, thanks to advanced after treatment systems and technological innovations, emission have been improved but, due to even higher costs and complexity of such systems and in a view of further emissions restrictions, advanced combustion methods leading to cleaner and improved efficiency combustion are under investigation. A possible path to follow in order to met requirements on lower emissions, is relative to so called low temperature combustion: a group of innovative combustion methods which by exploiting lean and premixed combustion decreases significantly flame temperature which is mainly responsible for nitrogen oxide production. This work of thesis focus on preliminary study, development and experimental testing of a low temperature combustion strategy, namely "gasoline direct compression ignition" also known as "GDCI".

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Pinazzi, Pietro Matteo. "Potential of ozone to enable the low load operation of a Gasoline Compression Ignition engine". Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2011.

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Le moteur essence à allumage par compression (GCI), reposant sur la combustion partiellement prémélangée de l'essence (GPPC), peut potentiellement assurer des opérations efficaces et propres. Le moteur GCI s'est avéré efficace à forte charge, mais l'indice d'octane élevé de l'essence limite considérablement les opérations à faible charge. Le présent travail étudie le potentiel de l'utilisation de l'ozone, fort agent oxydant, pour améliorer la réactivité de l'essence et permettre le fonctionnement à faible charge de GCI. L'ozone peut être produit on board en équipant le moteur d'un générateur d'ozone, sans impact dramatique sur le coût du moteur et sur la complexité du contrôle du moteur. Les essais effectués avec un moteur monocylindre ont montré que l'ozone favorise la combustion HCCI de l'essence, permettant d'étendre la limite d’auto-inflammation et de réduire la température minimale nécessaire de celle-ci. Les diagnostics optiques ont montré que ces propriétés sont liées à une prolifération radicale accrue, amenées par des réactions à basse température induites par l'ozone. En parallèle, le processus de combustion GCI a été étudié dans des conditions de faible charge. Sans ozone, la température d'admission doit être considérablement augmentée pour permettre l'auto-inflammationdes mélanges essence-air pauvres. De plus, les résultats indiquent que le monoxyde d’azote (NO) contenu dans les gaz brûlés résiduels peut, dans certaines conditions, favoriser fortement la combustion GCI. Ensuite,l'effet de l'ozone a été étudié dans des conditions d'injection directe GCI. Les résultats démontrent qu’une stratégie avec double injection est nécessaire pour maximiser l’effet promoteur de l’ozone et pour contrôler le processus de combustion GCI. Enfin, l'utilisation d’une forte concentration d’ozone a permis d’atteindre des opérations à faible charge en mode GCI, avec des faibles émissions de NOx et de suie, et cela, sans avoir besoin d'augmenter la température ou la pression d'admission
Gasoline Compression Ignition (GCI) engine, relying on Gasoline Partially Premixed Combustion (GPPC) has potential for efficient and clean operations. GCI engine showed to be effective at high load, however, the highoctane number of gasoline dramatically limits low load operations. The present work investigates the potential of using ozone, a strong oxidizing agent, to improve gasoline reactivity and enabling low load GCI operation.Ozone can be produced in-situ and on-demand by equipping the engine with an ozone generator, without a dramatic impact on the engine cost and the engine control complexity. Experiments in a single cylinder engine showed that ozone promotes gasoline HCCI combustion, making possible to extend the lean limit and reducing the minimum temperature needed for autoignition. Optical diagnostics showed that these properties are related to an increased radical proliferation related to ozone-induced low temperature reactions. In parallel, GCI combustion process was investigated under low load conditions. Without ozone, the intake temperature should be considerable increased to enable auto ignition of lean gasoline-air mixtures. Moreover, results indicated that the NO contained into residual burnt gases can strongly promote GCI low load combustion. Finally, the effect of ozone was investigated under GCI direct-injection conditions, demonstrating that low load GCI operation with low NOx and Soot emission can be achieved by seeding the intake of the engine with ozone without needing of increasing the intake charge temperature or boosting the intake pressure

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Milovanović, Nebojša. "A study of controlled auto ignition (CAI) combustion in internal combustion engines". Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/19906.

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Controlled Auto Ignition (CAI) combustion is a new combustion principle in internal combustion engines which has in recent years attracted increased attention. In CAI combustion, which combines features of spark ignition (SI) and compression ignition (CI) principles, air/fuel mixture is premixed, as in SI combustion and auto-ignited by piston compression as in CI combustion. Ignition is provided in multiple points, and thus the charge gives a simultaneous energy release. This results in uniform and simultaneous auto-ignition and chemical reaction throughout the whole charge without flame propagation. CAI combustion is controlled by the chemical kinetics of air/fuel mixture with no influence of turbulence. The CAI engine offers benefits in comparison to spark ignited and compression ignited engines in higher efficiency due to elimination of throttling losses at part and idle loads. There is a possibility to use high compression ratios since it is not knock limited, and in significant lower NOx emission (≈90%) and particle matter emission (≈50%), due to much lower combustion temperature and elimination of fuel rich zones. However, there are several disadvantages of the CAI engine that limits its practical application, such as high level of hydrocarbon and carbon monoxide emissions, high peak pressures, high rates of heat release, reduced power per displacement and difficulties in starting and controlling the engine. Controlling the operation over a wide range of loads and speeds is probably the major difficulty facing CAI engines. Controlling is actually two-components as it consists of auto-ignition phasing and controlling the rates of heat release. As CAI combustion is controlled by chemical kinetics of air/fuel mixture, the auto-ignition timing and heat release rate are determined by the charge properties such as temperature, composition and pressure. Therefore, changes in engine operational parameters or in types of fuel, results in changing of the charge properties. Hence, the auto-ignition timing and the rate of heat release. The Thesis investigates a controlled auto-ignition (CAI) combustion in internal combustion engines suitable for transport applications. The CAI engine environment is simulated by using a single-zone, homogeneous reactor model with a time variable volume according to the slider-crank relationship. The model uses detailed chemical kinetics and distributed heat transfer losses according to Woschini's correlation [1]. The fundamentals of chemical kinetics, and their relationship with combustion related problems are presented. The phenomenology and principles of auto-ignition process itself and its characteristics in CAI combustion are explained. The simulation model for representing CAI engine environment is established and calibrated with respect to the experimental data. The influences of fuel composition on the auto-ignition timing and the rate of heat release in a CAI engine are investigated. The effects of engine parameters on CAI combustion in different engine concepts fuelled with various fuels are analysed. The effects of internal gas recirculation (IEGR) in controlling the auto-ignition timing and the heat release rate in a CAI engine fuelled with different fuels are investigated. The effects of variable valve timings strategy on gas exchange process in CAI engine fuelled with commercial gasoline (95RON) are analysed.

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De, Lima Moradell Daniela Andreina. "Analysis of combustion concepts in a poppet valve two-stroke downsized compression ignition engine designed for passenger car applications". Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/68502.

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[EN] The research work presented on this thesis has been performed in the framework of the development and optimization of the combustion system of a novel two-stroke CI engine, with a scavenging configuration through poppet-valves, which has been specifically designed for a light-duty vehicle application. The main objective of this investigation is to improve the existing understanding about two-stroke poppet-valves engines, and assess the main relationships between the gas exchange and combustion processes in this type of architecture, with the aim of evaluating their impact on the exhaust emissions formation processes and on final engine efficiency. Then, the performance of this two-stroke engine is going to be optimized while operating in conventional diesel mixing-controlled controlled combustion; and in a second step, two advanced premixed combustion concepts will be evaluated to identify their potential for decreasing NOx and soot emissions compared to CDC as well as its main technological limitations. The methodology proposed on this thesis combines both a theoretical and experimental approach, that allows maximizing the available information about the basic phenomena involved in the various processes under study, while also keeping an efficient optimization approach to reduce as much as possible the number of necessary experimental tests. Additionally, to analyze in detail the physical relationships between the local cylinder gas conditions (such as the oxygen concentration, the combustion temperature and the equivalence ratio) and the formation of exhaust emissions, particularly NOx and soot, it was necessary to develop and setup different theoretical tools to complement and support the experimentally measured trends. To achieve these objectives, the research work has been divided in two sequential stages: first, the conventional diesel combustion is studied and optimized, based on a proper combination of engine settings that have a strong influence over the characteristics of the mixing-controlled combustion; and in a second step, two advanced combustion concepts are implemented and analyzed, the highly-premixed combustion (HPC) of diesel and the partially premixed combustion (PPC) using a fuel with higher resistance to autoignition (in this case it has been used a RON95 gasoline). In this phase of the research, special emphasis has been made to the gasoline PPC concept, since this combustion mode showed the highest potential and most promising results during the initial implementation studies. Accordingly, the last stage of the research was mainly focused on the detailed study of the effect of different injection settings over the characteristics of the gasoline PPC concept. Finally, the main results obtained with the gasoline PPC concept have been compared against the optimized points found in CDC, in regards to the final exhaust emissions levels, specific fuel consumption and indicated efficiency.
[ES] El trabajo de investigación presentado en esta tesis doctoral está enmarcado en el desarrollo y optimización del sistema de combustión de un novedoso motor de dos tiempos de encendido por compresión, que presenta una arquitectura de barrido por válvulas en culata, y que ha sido diseñado para aplicaciones de automoción dentro de la gama de coches compactos. El objetivo principal de esta investigación ha consistido en mejorar el conocimiento existente sobre los motores dos tiempos con arquitectura de barrido por válvulas, y a la vez identificar los principales vínculos entre los procesos de renovación de la carga y de combustión, con el fin de cuantificar su impacto sobre la formación de emisiones contaminantes y el rendimiento térmico del motor. Adicionalmente, se desea optimizar las prestaciones de este motor de dos tiempos operando con el proceso de combustión diésel convencional controlada por mezcla, así como evaluar el potencial de distintos conceptos avanzados de combustión de baja temperatura con fase de premezcla extendida, con el fin de reducir los niveles de emisiones contaminantes y mejorar el consumo específico de combustible del motor. La metodología utilizada en esta tesis ha sido concebida combinando un enfoque teórico-experimental, que permite maximizar la información que se puede obtener acerca de los fenómenos físicos involucrados en los diferentes procesos objeto de estudio, y a la vez conservar un enfoque de optimización eficiente reduciendo en la medida de lo posible el número de ensayos experimentales requeridos. Con la finalidad de analizar en detalle la relación que existe entre las condiciones en el cilindro (como lo es la concentración de oxígeno, la temperatura de combustión y el dosado local) y el proceso de formación de emisiones contaminantes, especialmente de NOx y hollín, se desarrollaron y utilizaron distintas herramientas teóricas para complementar y sustentar los comportamientos y tendencias observadas mediante los ensayos experimentales, tanto para el modo de combustión diésel convencional como para los conceptos avanzados de combustión. Para la consecución de dichos objetivos se ha seguido una estructura secuencial en la cual el trabajo de investigación ha sido desarrollado en dos grandes bloques: primero, se analizó y optimizó el proceso de combustión diésel convencional, mediante la combinación adecuada de parámetros de operación del motor que modifican apreciablemente las características del proceso de combustión controlada por mezcla; y segundo, se logró implementar y evaluar el desempeño de dos conceptos avanzados de combustión, específicamente el modo combustión altamente premezclado de tipo HPC utilizando diésel como combustible (acrónimo de "Highly-Premixed Combustion") y el modo de combustión parcialmente premezclada de tipo PPC ("Partially Premixed Combustion") utilizando un combustible con mayor resistencia a la auto-ignición (en este caso se utilizó gasolina de octanaje 95). En esta segunda fase, se hizo énfasis en el análisis del concepto de combustión PPC con gasolina, ya que este arrojó los resultados más prometedores durante la fase inicial de implementación. Consecuentemente, la última etapa de la investigación se centró en el estudio detallado del efecto de distintos parámetros de inyección sobre las características del proceso de combustión de tipo PPC. Finalmente, se ha comparado críticamente dicha operación en modo PPC con los resultados obtenidos operando con el modo de combustión diésel convencional, en cuanto al nivel final de emisiones contaminantes, al consumo de combustible y rendimiento indicado y al desempeño general del motor.
[CAT] El treball d'investigació presentat en esta tesi està emmarcat en el desenvolupament i optimització del sistema de combustió d'un nou motor dos temps d'encesa per compressió, amb configuració d'escombratge per vàlvules, i que ha estat dissenyat per a aplicacions d'automoció dins de la gamma de cotxes compactes. L'objectiu principal d'esta investigació ha consistit a millorar el coneixement existent sobre els motors dos temps amb configuració d'escombratge per vàlvules, així com també identificar els principals vincles entre els processos de renovació de la càrrega i de combustió, a fi de quantificar el seu impacte sobre la formació d'emissions contaminants i el rendiment tèrmic del motor. Addicionalment, es desitja optimitzar les prestacions d'este nou motor operant amb el mode convencional de combustió dièsel per difusió, així com avaluar el potencial de noves maneres de combustió de baixa temperatura amb fase de premescla extesa, per a controlar el nivell d'emissions i el consum de combustible. La metodologia utilitzada en esta tesi s'ha plantejat des d'un punt de vista teóric experimental, que permet maximitzar la informació que es pot obtindre sobre els fenòmens basics involucrats en els diferents processos objecte d'estudi, i al mateix temps conservar un enfocament d'optimització eficient reduïnt en la mesura del possible el nombre d'proves experimentals requerit. Amb la finalitat d'analitzar en detall la relació que existeix entre les condicions en el cilindre (com ho és la concentració d'oxigen, la temperatura de combustió i el dosatge local) i el procés de formació d'emissions contaminants, especialment de NOx i sutge, es van desenvolupar i van utilitzar distintes eines teòriques per a complementar i sustentar els comportaments i tendències observades per mitjà dels assajos experimentals, tant per al mode de combustió dièsel convencional com per als conceptes avançats de combustió. Per a abordar eixe objectiu, s'ha seguit una estructura seqüencial, en la qual el treball d'investigació s'ha desenvolupat en en dos grans blocs: en primer lloc, es va analitzar i va optimitzar el procés de combustió dièsel convencional, per mitjà de la combinació adequada de paràmetres d'operació del motor que modifiquen apreciablement les característiques del procés de combustió controlada per difusió; i en segon lloc, es va aconseguir implementar i avaluar les prestacions de dos conceptes avançats de combustió de baixa temperatura premesclats, específicament el mode combustió altament premesclat HPC (acrònim de "Highly-Premixed Combustion") utilitzant dièsel com a combustible i el mode de combustió parcialment premesclat PPC ("Partially Premixed Combustion") utilitzant un combustible amb major resistència a l'autoignició (en aquest cas s'ha utilitzat gasolina d'octanatge 95). En esta segona etapa, es va fer èmfasi en l'anàlisi del concepte de combustió PPC amb gasolina, ja que aquest va presentar els resultats més prometedors durant la fase inicial d'implementació. Conseqüentment, l'última etapa de la investigació es va centrar en l'estudi detallat de l'efecte de distints paràmetres d'injecció sobre les característiques del mode de combustió PPC. Finalment, s'ha comparat críticament la dita operació en mode PPC amb els resultats obtinguts operant amb el mode de combustió dièsel convencional, quant al nivell final d'emissions contaminants, al consum de combustible i rendiment indicat, i a les prestacions generals del motor.
De Lima Moradell, DA. (2016). Analysis of combustion concepts in a poppet valve two-stroke downsized compression ignition engine designed for passenger car applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68502
TESIS

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Surawski, Nicholas C. "An investigation of gaseous and particulate emissions from compression ignition engines operated with alternative fuels, injection technologies, and combustion strategies". Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/54194/1/Surawski_Thesis_2011.pdf.

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Whilst the compression ignition (CI) engine exhibits many design advantages relative to its spark ignition engine counterpart; such as: high thermal efficiency, fuel economy and low carbon monoxide and hydrocarbon emissions, the issue of Diesel Particulate Matter (DPM) emissions continues to be an unresolved problem for the CI engine. Primarily, this thesis investigates a range of DPM mitigation strategies such as alternative fuels, injection technologies and combustion strategies conducted with a view to determine their impact on the physico-chemical properties of DPM emissions, and consequently to shed light on their likely human health impacts. Regulated gaseous emissions, Nitric oxide (NO), Carbon monoxide (CO), and Hydrocarbons (HCs), were measured in all experimental campaigns, although the major focus in this research program was on particulate emissions...

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Duszynski, Marek. "Measurement of lubricant film thickness in reciprocating engines". Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8268.

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Prášek, Ondřej. "Návrh a posouzení alternativ přeplňování vznětového motoru s recirkulací". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228084.

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The object of this thesis was Proposal and Examination of Supercharging Alternatives of CI-engine with Exhaust Gas Recirculation according required engine power parameters. This goal was meet by use of Turbocharger with Variable Nozzles and Air-Air intercooler.

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Aklouche, Fatma Zohra. "Etude caractéristique et développement de la combustion des moteurs Diesel en mode Dual-Fuel : optimisation de l'injection du combustible pilote". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2018. http://www.theses.fr/2018IMTA0072/document.

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La dégradation de l’environnement ainsi que l’épuisement progressif des énergies fossiles devient très inquiétant et incite les états à définir des limites d’émission polluantes plus strictes. Ceci a conduit les constructeurs automobiles à poursuivre leurs recherches dans le développement de conception propre et efficace des moteurs en utilisant des combustibles alternatifs dans les moteurs à combustion interne.Dans le présent travail, on s’intéresse à l’étude des moteurs fonctionnant en mode DF afin d’améliorer ses performances tout en minimisant les émissions polluantes, en particulier les HC et les CO. Pour ce faire des études expérimentales ont été menées. Une réduction de 77% des émissions de HC a été observée en passant d’une richesse de 0,35 à 0,7. Par ailleurs, Il a été noté aussi qu’une diminution de 20% à 50% des émissions de CO avec une amélioration de 30% du rendement peut être visualisée en variant l’avance à l’injection de 4,5 °V à 6 °V. Concernant la mise en place de la pré-injection, une baisse de 30% des émissions de NOx a été observée avec un gain de 12% à 30% de rendement par rapport à une seule injection. En dernier terme, un modèle thermodynamique à une zone a été développé afin de prédire la température et la pression dans le cylindre. Une bonne concordance a été notée entre les deux résultats avec une erreur moyenne relative inférieure à 5%
Currently, the environmental degradation due to pollutant emissions and the gradual depletion of fossil fuels, becoming very worrying, are prompting European directives to set pollutant emission limits. These have led manufacturers to continue research in the development of clean and efficient engine designs using alternative fuels in internal combustion engines.In this work, we focus on the study of engines operating in dual-fuel mode to improve its performance while minimizing pollutant emissions, particularly HC and CO. For this, experimental studies were conducted. A reduction of about 77% in the HC emissions was observed as the equivalence ratio was varied from 0.35 to 0.7. Regarding the effect of injection timing, it was noted that the CO emissions decreased about 20% to 50% with an improvement in the brake thermal efficiency by 30% upon varying the injection advance from 4,5 °CA to 6 °CA. On the other hand, the introduction of pre-injection strategy led to a decrease by 30% in NOx emissions with an amelioration of brake thermal efficiency of 12% to 30% compared to a single injection. Lastly, a single zone thermodynamic model was developed to predict the in-cylinder temperature and pressure. A good agreement was noted between the predicted and experimental results. The average relative error was less than 5%

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Bennett, Guy Malcolm. "CFD modelling of ignition and combustion in diesel engines". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408413.

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Mbarawa, MM. "A correlation for estimation of ignition delay of dual fuel combustion based on constant volume combustion vessel experiments". The SA Mechanical Engineer, 2003. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001053.

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One method of using alternativefuels in diesel engines is by adopting amixed combustion process called dualfu elling w h er e alt ernativ e fu eI s uc h as natural gas (Ir{ G) is induc e d into the cylinder as a primary fuel with air and is subsequently isnited with a pilot injection of dieselfuel. The ignition delay in a dualfuel (DF) engine is differentfrom that in a diesel engine because the primaryfuelalters the properties of the charge, r e duc e o xy g e n av ailable and under go e s pr e -ignitio n r e ac tio n s durin g c o mp r e s s io n. V ario u s c o nclu sio n s of DF ignition delay have beenreachedusing different engines. In the presentwork a constantvolume combustionvessel (CVCV) has beenusedto study the ignition delay of aDF combustionpFocess. E xp erim e nt s hav e b e e n p e rform e d to inv e s tigat e th e i gniti o n d e lay p e rio d at dffi r e nt initial t e mp e r atur e s andpressures. The results obtainedwere usedto modify the Hu and Milton'ss DF ignition delay correlation. The proposed coruelation predicts a delay periodfor a wide range of initialtemperatures andpressures. The trends exhibitedby the correlation are consistentwith DF ignition delay engine tests datafrom other researchersl'2. In particular, it explains why some reported tests results show that ignition delay is always rising while others show that it decreases temporarily before rising againto very highvalues. The rising of ignition delay occurs withlow pilot diesel quantities and the latter with high one s.

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White, Timothy Ross Mechanical &amp Manufacturing Engineering Faculty of Engineering UNSW. "Simultaneous diesel and natural gas injection for dual-fuelling compression-ignition engines". Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/25233.

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The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.

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PRADELLE, FLORIAN ALAIN YANNICK. "USE OF BIOFUELS IN COMPRESSION IGNITION ENGINES: POTENTIAL OF DIESEL-BIODIESEL-ETHANOL BLENDS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29914@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
PROGRAMA DE EXCELENCIA ACADEMICA
BOLSA NOTA 10
Para substituir parcialmente a demanda em óleo diesel de origem fóssil, reduzir os elevados custos de importação e respeitar as normas ambientais, políticas sustentáveis já levaram a substituir parcialmente óleo diesel por biodiesel. Entretanto, outras tecnologias, como as misturas diesel-biodiesel-etanol, estão sendo investigadas. O principal desafio dessas misturas consiste em melhorar a miscibilidade e a estabilidade do álcool no óleo diesel. No presente trabalho, formulou-se um aditivo original, a partir de compostos renováveis, que permitiu melhorar a faixa de concentração de etanol anidro dentro de óleo diesel com 15 por cento em volume de biodiesel e de temperatura onde observa-se misturas estáveis. Diversas propriedades físico-químicas das misturas aditivadas foram medidas em uma larga faixa de concentração de etanol para avaliar os aspetos de consumo, qualidade da combustão, comportamento a baixa temperatura, interação entre fluido e superfície, e segurança. Os resultados obtidos mostraram que misturas com, pelo menos, 1,0 por cento em volume de aditivo e até 20 por cento em volume de etanol anidro são estáveis para temperaturas superiores a 10 graus Celsius e respeitam a maioria das especificações brasileiras atuais para óleo diesel. Ensaios experimentais em um motor de ignição por compressão MWM 4.10 TCA (Euro III) foram realizados com estas misturas. Os resultados obtidos mostraram que a substituição do óleo diesel altera as características da combustão: o crescente teor de etanol leva ao aumento do atraso de ignição, à liberação de calor mais rápida e à diminuição da pressão máxima. Mesmo nessas condições não otimizadas de injeção e de combustão, os resultados mostraram uma melhor conversão da energia química no etanol para produzir potência efetiva, comparado com os valores encontrados nos motores flex fuel de ciclo Otto, além de um pequeno aumento no rendimento térmico do motor.
In order to partially replace the demand of fossil diesel fuels, to reduce high import costs and to comply with environmental standards, sustainable policies have led to partially replace diesel fuel by biodiesel. However, other technologies, such as diesel-biodiesel-ethanol mixtures, are being investigated. The major challenge of these mixtures is to improve the miscibility and the stability of alcohol in diesel fuel. In this study, an original additive, from renewable compounds, improved the miscibility of anhydrous ethanol in diesel fuel with 15 per cent by volume of biodiesel and temperature in which stable mixtures were observed. Several physicochemical properties of the additivated mixtures were measured in a large range of ethanol concentration to evaluate aspects of consumption, combustion quality, behavior at low temperature, interaction between the fluid and the surface, and safety. The results showed that blends with, at least 1.0 per cent, by volume of additive and 20 per cent by volume of anhydrous ethanol are stable at temperatures above 10 degrees Celsius and respected most of the current Brazilian specifications for diesel fuel. Experimental tests on a compression ignition engine MWM 4.10 TCA (Euro III) were performed with these mixtures. The results showed that the diesel fuel substitution alters the characteristics of combustion: the increased ethanol content implied an increase of the ignition delay, a faster heat release and a decrease of maximum pressure. Despite these non-optimized conditions for injection and combustion, results showed a better conversion of ethanol chemical energy into brake power, in comparison to the values found in flex fuel spark ignition engine, in addition to a small increase in the indicated efficiency of the engine.

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Fayad, Mohammed Ali. "Particulate Matter (PM) characteristics from compression ignition diesel engines operated by renewable fuels". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7919/.

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Diesel engine emission of particulate matter (PM) is one of the most critical issues which have a large impact on the environmental and human health. The use of renewable fuels (biodiesel and butanol blend) and aftertreatment systems in diesel engines are the main requirements for reducing and controlling the pollutant emissions. To understand the effect of alternative fuels on PM characteristics and a diesel oxidation catalyst (DOC), rapeseed oil methyl ester (RME) biodiesel and an alcohol blend (butanol-diesel blend) were used for various engine operating conditions. The results revealed that the combustion of alternative fuels produces lower emissions of unburnt hydrocarbons (UHC), carbon monoxide (CO), and PM number concentration, which enhanced the catalyst activity at lower temperatures. Studying the effect of oxygenated fuel and fuel injection strategies on the combustion characteristics and PM characteristics, and hence the catalyst’s performance, can unveil synergies that can benefit vehicle emissions and fuel economy, as well as guide the design of the next generation of sustainable fuels. It was found that post-injection incorporation with a butanol blend produced lower PM concentration and modified the soot’s morphological parameters by reducing number of primary particles (npo), the radius of gyration (Rg), and the fractal dimension (Df).

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Moscato, André Luiz Salvat [UNESP]. "Otimização ecológica dos ciclos ar-padrão Otto e Diesel". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/115886.

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Made available in DSpace on 2015-03-03T11:52:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-13Bitstream added on 2015-03-03T12:06:10Z : No. of bitstreams: 1 000801083.pdf: 1280442 bytes, checksum: 6dcfc6fb20131fddca0a32bff15754cf (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Nestre trabalho é desenvolvida uma modelagem matemática para os ciclos irreversíveis Otto e Diesel. Os ciclos são analisados entre dois reservatórios com taxa de capacidade térmica infinita, com os processos de troca de calor ocorrendo em trocadores de calor entre o fluido de trabalho e os reservatórios térmicos. As irreversibilidades são decorrentes dos processos de troca de calor ocorrendo em tempo finito, da taxa de perda de calor do reservatório de alta temperatura para o reservatório de baixa temperatura e dos processos de compressão e expansão não-isoentrópicas. São utilizados três critérios de otimização: função ecológica, coeficiente ecológico de desempenho e potência máxima de saída. Estas funções são otimizadas com relação à temperatura de entrada no processo de adição de calor. São analisados as otimizações ecológicas e então comparadas com a potência máxima. Os resultados são apresentados através das curvas de potência e critério ecológico, eficiência térmica ecológico e taxa de geração de entropia e critério ecológico. São analisados os comportamentos de potência líquida, eficiência térmica e taxa de geração de entropia otimizadas ecologicamente através dos quais são avaliadas as influências de alguns parâmetros nos seus comportamentos. Por fim, são analisadas as razões entre a potência otimizada por critérios ecológicos e a potência máxima, eficiência térmica otimizada por critérios ecológicos e a eficiência térmica na condição de potência máxima, a taxa de geração de entropia otimizada por critérios ecológicos e a taxa de geração de entropia na condição de potência máxima. A análise dos resultados comprova que as otimizações ecológicas apresentam o melhor compromisso entre potência líquida e o ambiente. Os resultados poderão ser utilizados como critério relevante no aperfeiçoamento de projetos dos motores de combustão interna
In this work is developed a mathematical model for the irreversible Otto and Diesel cycles. The cycle is analyzed between two reservois with infinite thermal capacitance, where the processes of heat exchange occuring in the heat exchangers between the working fluid and the thermal reservoir at constant temperatures. The irreversibilities follow from the heat exchange processes occurring in finite time, the loss of heat from the hot source to the cold source and the noisentropic compression and expansion processes. Three optimization criteria are used: ecological function, ecological coefficient of performance and maximum power output. These functions are optimized with respect to the inlet temperature of heat addition process. Ecological optimizations are analyzed and compared to maximum power. The results are presented through the power and ecological creteria, thermal efficiency and ecological criteria and entropy generation rate and ecological criteria curves. The results are presented though the power curves and ecological criteria, thermal efficiency and ecological and entropy generation rate and ecological criteria. Analyzes the behavior of power, efficiency and rate of entropy generation ecologically optimized through which they are evaluated the influences of some parameters on their behavior. Finally, we analyze the ratio between ecological criteria for optimum power and maximum power, optimized thermal efficiency by ecological criteria and the maximum power efficiency, the ratio between the entropy generation rate optimized for ecological criteria and entropy generation rate of maximum power. The results show that the ecological optimizations present the best compromisse between power and environment. The results can be used as an important criterion in developing projects of internal combustion engines

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GUEDES, ANDREW DAVID MENDES. "EXPERIMENTAL STUDY ABOUT ETHANOL IMPACT IN DIESEL-BIODIESEL-ETHANOL BLENDS IN COMPRESSION IGNITION ENGINES". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=30923@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
AGÊNCIA NACIONAL DE PETRÓLEO
Há algum tempo biocombustíveis renováveis são potenciais soluções sugeridas às questões de emissão de poluentes e dependência da sociedade aos derivados fósseis. Biodiesel e etanol são combustíveis comerciais renováveis candidatos à substituição das fontes fósseis, especialmente, em motores de ignição por compressão, os quais são tipicamente mais eficientes do que aqueles de ignição por centelha. Misturas ternárias de diesel, biodiesel e etanol formam estratégias de substituição parcial do diesel aplicáveis em motores de ignição por compressão sem a necessidade de grandes adaptações. Nesta dissertação realizaram-se avaliações experimentais em um motor multi-cilíndrico de ignição por compressão (MWM 4.10 TCA), abastecido com misturas de diesel, biodiesel (até 15 por cento em teor volumétrico) e etanol anidro (até 20 por cento em teor volumétrico). Cada mistura ternária é composta por diferentes proporções do álcool e sempre com a concentração volumétrica de 1 por cento de um aditivo estabilizador da mistura. Portanto, os testes associam substituições parciais do diesel por biocombustíveis a avaliações de desempenho do motor e da combustão das misturas, sob algumas condições de carga, regimes de rotação e instantes de injeção de combustível. Os testes realizados indicam que misturas com 20 por cento em volume de concentração de etanol experimentam inícios de combustão até 4,7 graus CA mais atrasados. Porém, a busca de instantes otimizados na injeção de combustível trouxe melhorias ao desempenho do motor, permitiu conversões energéticas mais vantajosas do etanol na ignição por compressão frente à ignição por centelha, além de minimizar efeitos do etanol em retardar o início da combustão.
Renewable biofuels have been proposed for a long time as an alternative to the issues concerned to pollutants emission and also society s liability to fossil fuels. Biodiesel and ethanol are renewable commercial fuel candidates for fossil fuels substitution, especially, in compression ignition engines, which are typically more efficient than the spark ignition ones. Diesel s partial replacement, such as the substitution by ternary blends formed by diesel, biodiesel and ethanol, is a strategy applicable to compression ignition engines without the need of further modifications. In this dissertation tests were run in a multi-cylinder compression ignition engine (MWM 4.10 TCA), fueled with diesel, biodiesel (up to 15 percent in volumetric content) and anhydrous ethanol (up to 20 percent in volumetric content) blends. Each mixture should be composed by different alcohol s proportions and always containing a 1 percent volumetric concentration of additive in order to ensure ternary s blend stability. Therefore, tests try to ally diesel s partial replacement by biofuels with engine performance and blends combustion assessment, under some combinations of load, engine speed and injection timing conditions. The tests performed indicate that the start of the combustion experienced up to 4.7 degrees CA postponements, when fueled with a 20 percent ethanol volumetric concentration blend. Still, optimized injection timing investigation brought improvements to engine performance, allowed better ethanol energetic conversions through compression ignition when compared to spark ignition and could also minimize delays caused by ethanol s presence in the beginning of the combustion.

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Crawford, Morgan H. "Feasibility and Emissions of Compression Ignition Engines Fueled with Waste Vegetable Oil". [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000193.

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Melhus, Øyvin. "Utilisation of VOC in Diesel Engines. Ignition and Combustion of VOC Released by Crude Oil Tankers". Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-387.

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The emission of VOC (Volatile Organic Compound) has been identified as a significant source of hydrocarbon pollution. It is many sources of VOC emission. A major one in Norway is caused by the offshore oil industry. In the Norwegian part of the North Sea, the contribution from shuttle tankers loading crude oil at the oil fields is about 215000 tons a year (1997). This emission represents both an energy loss and an environmental problem.

Gas tankers have used boil-off gas from the cargo tanks as fuel for some time. However, for the current VOC project a new fuel injection concept is designed for tankers to take advantage of the energy present in the VOC evaporated from crude oil. The VOC is mixed with inert gas in these tankers, and thus the utilisation of this gas represents new challenges. The VOC project uses the concept of «Condensate Diesel Process» with pilot ignition.

An experimental study of ignition and combustion of VOC Fuels reported here was initiated by the time it was decided to start a pilot project converting propulsion engines in shuttle tankers to use VOC Fuel. It is an experimental study carried out at the Marine Technology Centre (MTS). The objective was to study ignition and combustion of the chosen process in comparison with an ordinary diesel process.

The experimental results have been discussed and are compared with theoretical considerations of injection, ignition and combustion.

For experiments on combustion, a rapid compression machine "DyFo", which was developed during the years from 1992 to 1997, was redesigned to use VOC Fuel. The DyFo test rig was initially designed to study ignition and early combustion of spark ignited homogeneous gas/air charges. To study the ignition and early combustion of VOC Fuel injected at high pressure and ignited by pilot diesel fuel, a redesign was necessary. An important feature of the DyFo, is the visualisation of the combustion.

The advantage of the DyFo test rig, compared to an engine, is its simplicity and controllability. All test parameters and variables are better controlled and this makes comparable tests easier to perform. In an engine the visualisation would suffer from combustion deposits disturbing the view through the quartz glasses, making the images more difficult to interpret. The simplicity is on the other side a drawback. Correct thermal conditions inside the cylinder is hard to obtain as the piston only is moved one half stroke (from BDC to TDC) for each test. External heating of the test rig is necessary, and this makes it difficult to obtain correct thermal conditions for other than low load conditions.

An injector of a new, common rail type design is developed for injection of the VOC Fuel. The design, based on a conventional, redesigned diesel fuel nozzle involved a lot of practical problems. Leakages of gas into the combustion chamber have led to some accidents resulting in too high cylinder pressures. However, broken quartz glasses have been the most serious result of the malfunctions.

The main purpose of this investigation has been to study the combustion of alkanes present in the VOC evaporated from crude oil. The primary objective was to verify whether or not the concept of the «Condensate Diesel Process» with pilot ignition can be used to utilise these hydrocarbons as fuel in Diesel engines. VOC Fuels of different composition have been tested.

The experiments carried out have not revealed any problems concerning combustion when using pilot ignited VOC Fuel. Both ignition and combustion seem to follow the traditional diesel scheme. The composition of the VOC Fuel seems not to affect the ignition delay. A study of varying the value of different parameters has not unveiled any surprises regarding the ignition or early combustion.

Separate tests with pure VOC Fuel components, however, show great differences in the ignition delay (both regarding mean value and variance) for different components. The component being most unwillingly and most unstable to ignite is propane. If, for some reason, the pilot ignition should fail, a VOC Fuel with mainly n-butane and higher alkanes will probably give no great operating problems, at least not at medium to high engine load.

These conclusions are mainly based on the analysis of the dynamic signals from the pressure sensor giving the cylinder pressure curves. Where found appropriate, Schlieren images have been included in the discussion. However, the use of Schlieren images has been found to be less valuable for the Diesel process than for the Otto process. The reason for this is mainly that the radiation of visible light from the diffusion combustion of diesel oil and VOC Fuel (i.e. propane, iso-butane and n-butane) are quite different. First, this radiation disturbs the Schlieren image and second, the radiation from the combustion of diesel oil is far more intense than that of the VOC Fuel.

The light VOC fraction of the vent gas – methane and ethane – is not utilised in the concept of «Condensate Diesel Process». This fraction represents about 15 % of the total energy in the VOC release when loading crude oil at the Statfjord field. At other fields as Gullfaks, this fraction can represent up to 50% or more of the total energy. After the VOC Fuel is produced, a residual VOC consisting of methane, ethane, some propane and inert gas is lost.

A useful and simple way of utilising even this fraction is to mix it with the charge air at low pressure and feed the mixture into the cylinder where a pilot fuel spray ignites the charge. The method is found to have potential of being a suitable way, at least theoretically, to utilise the light VOC fraction. Some practical difficulties, however, may restrict the use of this fraction to medium and high engine loads. At lower loads the ignition delay increases due to the dilution with great quantities of inert gas.

Another option to utilise the light VOC fraction is by capturing the gas in hydrates. No real study of this concept has been carried out, but an initial survey of possible solutions is described. A final conclusion of the potential of this concept cannot be drawn until more detailed work has been carried out. However, simply using the light VOC fraction extracted by melting the hydrate will be the most likely way.

As a main conclusion it can be stated that the use of VOC Fuel in a «Condensate Diesel Process» is a feasible way of utilising energy otherwise lost. Venting the VOC to the atmosphere when loading crude oil into shuttle tankers represents both an energy loss and an environmental problem. By reducing both, the idea of using VOC as an engine fuel seems to be a good one.

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Peraza, Ávila Jesús Enrique. "Experimental study of the diesel spray behavior during the jet-wall interaction at high pressure and high temperature conditions". Doctoral thesis, Universitat Politècnica de València, 2020. http://hdl.handle.net/10251/149389.

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[EN] The potential of diesel engines in terms of robustness, efficiency and energy density has made them widely used as power generators and propulsion systems. Specifically, fuel atomization, vaporization and air-fuel mixing, have a fundamental effect on the combustion process, and consequently, a direct impact on pollutant formation, fuel consumption and noise emission. Since the combustion chamber has a limited space respect to the spray penetration, wall impingement is considered to be a common event in direct injection diesel engines, having a relevant influence in the spray evolution and its interaction with both surrounding air and solid walls. This makes of spray-wall interaction an important factor for the combustion process that is still hardly understood. At cold-start conditions, the low in-chamber pressures and temperatures promote the deposition of fuel in the piston wall, which leads to a boost in the formation of unburned hydrocarbons. Additionally, modern design trends such as the increment of rail pressures in injection systems and the progressive reduction of the engine displacement, favor the emergence of spray collision onto the walls. In spite of the evident relevance of the comprehension of this phenomenon and the efforts of engine researchers to reach it, the transient nature of injection process, its small time scales and the complexity of the physical phenomena that take place in the vicinity of the wall, make challenging the direct observation of this spray-wall interaction. Even though computational tools have proven to be priceless in this field of study, the need for reliable experimental data for the development of those predictive models is present. This thesis is aimed to shed light on the fundamental characteristics of spray-wall interaction (SWI) at diesel-like chamber conditions. A flat wall was set at different impingement distances and angles respect to the spray. In this way, two different kinds of experimental investigations on colliding sprays were carried out: A transparent quartz wall was employed into the chamber to, in isolation, analyze the macroscopic characteristics of the spray at both evaporative inert and reactive conditions, which have been observed laterally and through the wall, thanks to the use of a high-pressure and high-temperature vessel with optical accesses. This same test rig was used in the second kind of experiments, where instead of the quartz plate, a stainless steel wall was used to capture the effect of the operating conditions on the heat flux between the wall and the spray during the injection-combustion events and to determine how spray and flame evolution are affected by realistic heat transfer situations. This wall was instrumented to control its initial in-chamber surface temperature and to measure its variation with time by using high-speed thermocouples. Tests at free-jet conditions were also performed in order to provide a solid comparative base for those experiments.
[ES] El potencial de los motores diesel en términos de robustez, eficiencia y la densidad de energía los ha hecho ser ampliamente usados como generadores de energía y sistemas propulsivos. Específicamente, la atomización de combustible, vaporización y mezcla de aire y combustible tienen un efecto fundamental en el proceso de combustión y, en consecuencia, un impacto directo en la formación de emisiones contaminantes, consumo de combustible y generación de ruido. Dado que la cámara de combustión tiene un espacio limitado con respecto la capacidad de penetración del chorro, el impacto de la pared se considera bastante común en motores de inyección directa diésel, que tienen una influencia relevante en la evolución del chorro y su interacción con el aire circundante y las paredes sólidas. Esto hace de interacción chorro-pared, un factor importante para el proceso de combustión que aún es dificilmente comprendido. En condiciones de arranque en frío, las bajas presiones y temperaturas en la cámara promueven la deposición de combustible en la pared del pistón, lo que conduce a un aumento en los niveles de formación de hidrocarburos no quemados. Además, las tendencias modernas de diseño como el incremento de las presiones de rail en los sistemas de inyección y la progresiva reducción en la cilindrada de los motores, favorecen la aparición de colisiones entre chorro y pared. A pesar de la evidente importancia en la comprensión de este fenómeno y los esfuerzos de los investigadores para alcanzarla, la transitoria naturaleza del proceso de inyección, sus pequeñas escalas de temporales y la complejidad de los fenómenos físicos que tienen lugar en las proximidades de la pared, hacen que la observación directa de esta interacción chorro-pared sea un desafío. Aunque las herramientas computacionales han demostrado ser invaluables en este campo de estudio, la necesidad de datos experimentales confiables para el desarrollo de esos modelos predictivos está muy presente. Esta tesis tiene como objetivo arrojar luz sobre las características fundamentales de la interacción chorro-pared (SWI por sus siglas en inglés) en condiciones de cámara similares a las de un motor diesel. Se colocó una pared plana a diferentes distancias de impacto y ángulos con respecto al jet. De esta manera, dos tipos diferentes de investigaciones experimentales sobre chorros en colisión se llevaron a cabo: se empleó una pared de cuarzo transparente en la cámara para, de forma aislada, analizar las características macroscópicas del chorro en condiciones evaporativas inertes y reactivas, que pueden observarse lateralmente y a través de la pared, gracias al uso de una instalación de alta presión y alta temperatura ópticamente accesible. Esta misma instalación se utilizó en el segundo tipo de experimentos en los que se introdujo una pared de acero inoxidable para capturar adicionalmente el efecto de las condiciones de operación en el flujo de calor entre ésta y el chorro durante los eventos de inyección y combustión y para determinar cómo la evolución del chorro y la llama son afectadas por una situación realista de transferencia de calor. Esta pared fue instrumentada para controlar la temperatura inicial de su superficie expuesta a la cámara y medir su variación con el tiempo, utilizando termopares de alta velocidad. Ensayos en condiciones de chorro libre también se realizaron para proporcionar una base comparativa sólida para esos experimentos.
[CA] El potencial dels motors dièsel en termes de robustesa, eficiència i la densitat d'energia els ha fet ser àmpliament usats com a generadors d'energia i sistemes propulsius. Específicament, l'atomització de combustible, vaporització i barreja d'aire i combustible tenen un efecte fonamental en el procés de combustió i, en conseqüència, un impacte directe en la formació d'emissions contaminants, consum de combustible i generació de soroll. Atès que la cambra de combustió té un espai limitat pel que fa la capacitat de penetració de l'raig, l'impacte de la paret es considera bastant comú en motors d'injecció directa dièsel, que tenen una influència rellevant en l'evolució del doll i la seva interacció amb el aire circumdant i les parets sòlides. Això fa d'interacció doll-paret, un factor important per al procés de combustió que encara és difícilment comprès. En condicions d'arrencada en fred, les baixes pressions i temperatures a la cambra promouen la deposició de combustible a la paret del pistó, el que condueix a un augment en els nivells de formació d'hidrocarburs no cremats. A més, les tendències modernes de disseny com l'increment de les pressions de rail en els sistemes d'injecció i la progressiva reducció en la cilindrada dels motors, afavoreixen l'aparició de col·lisions entre el doll i la paret. Tot i l'evident importància en la comprensió d'aquest fenomen i els esforços dels investigadors per aconseguir-la, la transitòria naturalesa de l'procés d'injecció, les seves petites escales de temporals i la complexitat dels fenòmens físics que tenen lloc en les proximitats de la paret , fan que l'observació directa d'aquesta interacció doll-paret siga un desafiament. Tot i que les eines computacionals han demostrat ser invaluables en aquest camp d'estudi, la necessitat de dades experimentals fiables per al desenvolupament d'aquests models predictius està molt present. Aquesta tesi té com a objectiu donar llum sobre les característiques fonamentals de la interacció doll-paret (SWI per les seues sigles en anglès) en condicions de cambra similars a les d'un motor dièsel. Es va col·locar una paret plana a diferents distàncies d'impacte i angles pel que fa al jet. D'aquesta manera, dos tipus diferents d'investigacions experimentals sobre dolls en col·lisió es van dur a terme: es va emprar una paret de quars transparent a la cambra per, de forma aïllada, analitzar les característiques macroscòpiques del doll en condicions evaporació inerts i reactives, que poden observar lateralment i a través de la paret, gràcies a l'ús d'una instal·lació d'alta pressió i alta temperatura òpticament accessible. Aquesta mateixa instal·lació es va utilitzar en el segon tipus d'experiments en els quals es va introduir una paret d'acer inoxidable per capturar addicionalment l'efecte de les condicions d'operació en el flux de calor entre aquesta i el dull durant els esdeveniments d'injecció i combustió i per determinar com l'evolució del doll i la flama són afectades per una situació realista de transferència de calor. Aquesta paret va ser instrumentada per controlar la temperatura inicial de la seua superfície exposada a la càmera i mesurar la seua variació amb el temps, utilitzant termoparells d'alta velocitat. Assajos en condicions de doll lliure també es van realitzar per proporcionar una base comparativa sòlida per a aquests experiments.
Peraza Ávila, JE. (2020). Experimental study of the diesel spray behavior during the jet-wall interaction at high pressure and high temperature conditions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149389
TESIS

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Scarpin, Lucas Mendes. "Avaliação experimental do desempenho de um motor de ignição por compressão operando com misturas Diesel-Etanol Anidro ou com sistema eletrônico independente de injeção de Etanol Hidratado /". Ilha Solteira, 2019. http://hdl.handle.net/11449/182010.

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Singh, Devendra. "Experimental investigations on utilization of hydro-processed renewable diesel in a compression ignition engine". Thesis, 2018. http://eprint.iitd.ac.in:80//handle/2074/7944.

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Galligan, Derek T. "Effect of ignition and combustion on diesel engine emissions". 2001. http://www.library.wisc.edu/databases/connect/dissertations.html.

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Spaeth, Christopher Thomas. "Performance Characteristics of a Diesel Fuel Piloted Syngas Compression Ignition Engine". Thesis, 2012. http://hdl.handle.net/1974/7221.

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The performance characteristics of a diesel fuel piloted syngas compression ignition engine are presented in this thesis. A stock Hatz 1D81 engine was converted to operate in dual fuel mode through the elimination of the governor system and addition of an in-cylinder pressure transducer and custom intake system to facilitate the mixing of the gaseous fuel and combustion air. The engine was run on a Superflow water brake dynamometer and benchmarked with diesel to compare against manufacturer specifications. This was followed by dual fuel operation on methane and syngas, with the results being compared through performance characteristics. When operated on methane, the engine attained higher peak in-cylinder pressures along with higher torque, power, and thermal efficiency values for equal equivalence ratios. It was necessary to use greater amounts of syngas to reach comparable results with methane due to the lower energy content of syngas. The ignition delay was greater for syngas, and the onset of knock occurred earlier with syngas in comparison to methane. The heat release, Q, was comparable for both fuels and the exhaust gas emissions were significantly lower for operation with syngas. With emphasis on clean engine operation, syngas operation proved to be viable due to its renewable nature, significantly lower exhaust gas emissions, equal heat release characteristics, and larger useable operating range when compared to methane.
Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-05-28 15:02:49.227

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