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Molecular characterisation and modelling for refining processesLiu, Luyi January 2015 (has links)
The highly competitive market in the oil refining industry forces refiners look for more detailed information of both feedstocks and products to achieve the optimal economic performance. Due to stricter environmental legislations, the molecular level characterisation has been investigated by various researchers and shows promising advantages in modern refinery design and operation. Although various molecular characterisation methods have been developed, there is an unavoidable trade-off between keeping astronomical molecule details and practicality in industrial applications. In the meantime, many of these methodologies have different characteristics and different focuses according to a particular application purpose. Our aim is hence to tackle the problems of developing manageable and practical technical solutions for molecular characterisation of petroleum fractions for vary refinery processes. A pseudo-component based approach is developed within a modified MTHS (Molecular Type Homologous Series) matrix framework (Peng, 1999) to represent the molecular information of a particular refining stream. This proposed methodology incorporates both molecular type and pseudo-component information by the conjunction of homologous series and boiling points in the matrix framework. To increase the usability of this method, a 3-parameter gamma distribution function is introduced to describe the composition of each structural molecular type. Typical PIONA (paraffin, iso-paraffin, olefin, naphthene, aromatic) analysis, ratios between each homologous types and the percentage of particular carbon type are considered as well as the distillation curve and the density of a stream. More strict product specifications and environmental legislations make strong restriction to the benzene and aromatics content in gasoline products, which motivate refiners to understand, characterise and simulate gasoline catalytic reforming on molecular-level. In this work, kinetic and reactor model of naphtha catalytic reforming is developed based on the proposed MTHS method. The naphtha feedstock composition is represented by the MTHS matrix, and a kinetic network is constructed according to conversions among matrix elements. A process model proposed by Wu (2010) is employed for reforming modelling. The proposed model is then applied to a bench-scale semi-regenerative catalytic reforming unit, which contains 3 fixed-bed reactors, for validation. The influences of essential operating conditions, such as reactor inlet temperature, pressure and weight hourly space velocity (WHSV), on the product distribution and quality are explored. The developed characterisation is also applied in gasoline blending modelling. A molecular-level nonlinear gasoline blending model is developed based on proposed MTHS method with validation. Key properties such as Octane Numbers (ONs) and RVP are blended by molecular matrix elements, and the influence of molecular composition on bulk properties is obvious. A case of recipe optimisation is studied to show the applicability of the proposed method. The implementation of the developed MTHS method for catalytic reforming and gasoline blending demonstrates the compatibility when characterising different petroleum streams, and provides a common platform to simulate and optimise refining operations on the same molecular basis.
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Engine stability : A study of the events occurring prior to thecombustion in a small two-stroke engineAlexander, Mattsson January 2017 (has links)
This thesis is a study conducted in collaboration with the engine performance group atHusqvarna AB. The study focuses on engine stability of smaller two stroke handheld enginesrunning on E10 (10% ethanol mixture in gasoline). The reason for the study is the new EUproposition that by 2020 all fuel must have 10 % renewable fuel content. To meet thisproposition Husqvarna has evaluated E10 and found that the engine stability of smaller twostroke engines are affected in a negative way by the fuel.The study focuses on events occurring prior to the combustion and mainly the carburetor. Theobjective for the thesis is to seek what contribution the events occurring prior to thecombustion have to the engine stability and find simple and implantable solution to improvethe stability with regards to the carburetor.The study has been conducted in three different work packages, system understanding to buildknowledge of how the carburetor operates, fault finding to seek potential attributes that canaffect the stability and fault mode analysis to seek why the attributes affect the stability.Furthermore, all the attributes found has been tested and validated on the engine to seek theircontribution to the stability.The conclusion made of the thesis is that with simple and implementable improvements of thecarburetor the engine stability could be increased with 40 %. A total of five differentattributes were found to affect the stability of the engine. Furthermore, a very detailedexplanation of how the carburetor operates and components inside the carburetor has beenestablished during the thesis.
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Analýza závislostí stanovování cenových hladin a objemu prodaného množství benzínu u vybraného distributora v České republice a Polsku / Analysis of the price level and gasoline quantum sold at a chosen distributor in the Czech Republic and in PolandHlůšek, Jakub January 2013 (has links)
The aim of the thesis was to analyse dependency between setting of the price level and gasoline quantum sold at a chosen distributor in the Czech Republic and in Poland. In the first part of the thesis, there are characterized price theory, tax theory, theory of state interventions, supply, demand and price elasticity of demand. In the second part, first, there is analysed whole market with fuels in both countries with their comparison. These markets have had slightly different development and they do have different market structure, because of the existence of the market leader in Poland. Second, there are analysed the data of the chosen distributor and analysed dependencies between price and quantum sold. Research showed that there is an existence of dependencies of quantum sold on both change of the absolute price and change of the relative price. These dependencies and the impact of the relative price change is more significant in the Czech Republic than in Poland.
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Fischer-Tropsch refiningDe Klerk, Arno 28 July 2008 (has links)
Energy carriers, such as coal, natural gas and biomass, can be converted by Fischer-Tropsch technology into synthetic crude (syncrude). Fischer-Tropsch derived syncrude can then be refined to transportation fuels, such as motor-gasoline, jet fuel and diesel fuel. These fuels meet the same specifications as crude oil derived transportation fuels. Conventional refining technologies have to be adapted to deal with Fischer-Tropsch syncrudes, because they differ significantly from crude oil with respect to composition. Some of the key differences are the high concentration of oxygenates and olefins and absence of sulphur in Fischer-Tropsch syncrude. Imposing a crude oil refining methodology on syncrude can lead to unwieldy and expensive refineries. Yet, despite an abundance of literature of Fischer-Tropsch synthesis, there is little literature that deals with the refining of Fischer-Tropsch syncrude. The present study investigated current refining practice for both crude oil and Fischer-Tropsch syncrude in order to identify fundamental differences in their refining focus and conversion behaviour. This was followed by a critical evaluation of the compatibility of syncrudes from high temperature Fischer-Tropsch (HTFT) and low temperature Fischer-Tropsch (LTFT) synthesis with the chemistry and catalysis of various conversion processes. The conversion processes that were evaluated include isomerisation, oligomerisation, etherification, alkylation, metathesis, hydrogenation, hydroisomerisation, hydrocracking, catalytic cracking, coking, thermal cracking, catalytic reforming and dehydration. The recommendations from the technology evaluation provided the foundation for the development of Fischer-Tropsch syncrude based refinery designs. Refinery designs were developed to determine configurations that would maximise the production of on-specification motor-gasoline, jet fuel and diesel fuel respectively. It could be shown that less complex refinery designs were required to refine Fischer-Tropsch syncrude to motor-gasoline and jet fuel, than were required for crude oil refining. It was also shown that on a molecular level Fischer-Tropsch syncrude is unsuited for maximising the production of Euro-4 type diesel fuel. The present study illustrates the advantage of considering fundamentals in developing refineries specifically for Fischer-Tropsch syncrude, rather than imposing crude oil design practises on Fischer-Tropsch syncrude refinery designs. / Thesis (PhD (Chemical Engineering))--University of Pretoria, 2008. / Chemical Engineering / unrestricted
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Desenvolvimento de um fotometro portatil NIR para determinação do teor de agua no alcool combustivel e do teor de etanol na gasolina / Development of a portable near infrared photometer for determination of quality parameters of gasoline and alcohol fuelChagas, Ismael Pereira 18 July 2006 (has links)
Orientador: Jarbas Jose Rodrigues Rohwedder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T20:00:15Z (GMT). No. of bitstreams: 1
Chagas_IsmaelPereira_D.pdf: 2025832 bytes, checksum: 8e2e4a99a15486f48f4aae44dfd6f183 (MD5)
Previous issue date: 2006 / Resumo: Neste trabalho, foi desenvolvido um fotômetro NIR portátil para determinar o teor de água em álcool combustível hidratado combustível (AEHC) e o teor de etanol (Álcool etílico anidro carburente) em gasolina. Foram realizados inicialmente estudos espectroscópicos empregando um espectrofotômetro comercial para avaliar quais as melhores regiões do espectro NIR que poderiam ser empregadas para a determinação das espécies de interesse. No desenvolvimento do instrumento foram avaliados detetores baseados em um foto resistor de PbS e um fotodiodo de InGaAs. Dentre os detectores empregados o que apresentou melhores resultados foi o detector de InGaAs. Foram construídos diversos fotômetros sendo que aqueles que apresentaram as melhores performance utilizaram filtro de interferência em 1480 nm e celas cilíndricas com caminho óptico de 2 mm e 5 mm. Para o caminho óptico de 2 mm, foi utilizada como fonte de radiação uma lâmpada de 6 watts, enquanto que para a cela com 5 mm foi utilizada uma lâmpada de tungstênio de 20 watts e uma lente colimadora. Em ambos os casos, a fonte de radiação foi pulsada a uma freqüência de 25 Hz. Como transdutores de saída do instrumento foram empregados um microcontrolador PIC acoplado à um display de cristal líquido e também dois LEDs (vermelho e verde) indicando se o combustível estava dentro ou fora da especificação. O instrumento foi avaliado com amostras comerciais de álcool combustível e gasolina. Para a determinação do teor alcoólico em álcool combustível, a resposta é linear na faixa de concentração de 88 a 98% m/m, com um erro médio de 3,6 % para um total de 30 amostras analisadas, quando comparada ao seu respectivo método de referência. Na análise de amostras de gasolina foi obtida uma resposta linear para o teor de etanol entre 20 % e 30 %, com um erro médio de 3,0% para um total de 40 amostras analisadas. A ANP considera até 4% de erro médio e desta forma o instrumento classifica corretamente 100 % das amostras / Abstract: In this work a portable Near Infrared Photometer to determine the quantity of water in alcohol fuel and the quantity of ethanol in gasoline was developed. Initially, several spectroscopy analysis using a comercial spectrophotometer was made to select the best wavelenghts to determine those fuel quality parameters. The wavelengths of 1480 nm and 1920 nm were selected after preliminary study. The instrument was evaluated using two types of detectors: a PbS photoresistive detector and a InGaAs photodiode. The detector with best performance was the InGaAs photodiode. Different prototypes were built using a interference filter working in 1480 nm and path length with 2 mm and 5 mm. With the 2 mm path length was used a 6 watt tungsten lamp as radiation source and with 5 mm path length was used a 20 watts tungten lamp. This interference filter can be used to determine water in alcohol fuel and ethanol in gasoline without any changes in the instrument. The final version of the prototype showing the best results for both determinations uses a cilindric cell with 5 mm diameter and can be employed for flow or batch measurements, radiation source of a 20 watts tungsten lamp pulsed at 25 Hz and a lens to focus the infrared radiation into the detector. The output transducers of the instrument was a PIC microcontroller with a liquid crystral display and light emission diodes (LEDs) green and red. The instrument was tested using comercial fuel alcohol and gasoline samples. In the determination of water in alcohol it was obtained a linear response in the concentration range from 98 to 88 % (m/m) and in gasoline, it was 20 % to 30 %(v/v). Thirty alcohol samples were analysed showing a standard error of 3,6 % while for the gasoline, a standard error of 3,0% for a total of 40 samples analysed was found. Considering the tolerance of 4%, recommended by the National Pretoleum Agency (ANP), the instrument can classify normal and adultered samples with confidence of 100% / Doutorado / Quimica Analitica / Doutor em Quimica
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A solution to misfuelling and a new experience in car refueling.Stefou, Stefanos January 2020 (has links)
The purpose of this thesis is to clarify to the reader the problem of misfuelling, which is the insertion of the wrong fuel in an engine, incompatible with the fuel inserted. Additionally, it contains research about the causes of this problem, current solutions in the market and a suggested solution according to the prior research and the findings of this thesis.
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Study of Organic Rankine Cycles for Waste Heat Recovery in Transportation VehiclesRoyo Pascual, Lucía 29 June 2017 (has links)
Regulations for ICE-based transportation in the EU seek carbon dioxide
emissions lower than 95 g CO2/km by 2020. In order to fulfill these
limits, improvements in vehicle fuel consumption have to be achieved. One
of the main losses of ICEs happens in the exhaust line. Internal combustion
engines transform chemical energy into mechanical energy through
combustion; however, only about 15-32% of this energy is effectively used
to produce work, while most of the fuel energy is wasted through exhaust
gases and coolant. Therefore, these sources can be exploited to improve the
overall efficiency of the engine. Between these sources, exhaust gases show
the largest potential of Waste Heat Recovery (WHR) due to its high level of
exergy. Regarding WHR technologies, Rankine cycles are considered as the
most promising candidates for improving Internal Combustion Engines.
However, the implementation of this technology in modern passenger cars
requires additional features to achieve a compact integration and controllability
in the engine. While industrial applications typically operates in
steady state operating points, there is a huge challenge taking into account
its impact in the engine during typical daily driving profiles.
This thesis contributes to the knowledge and characterization of an
Organic Rankine Cycle coupled with an Internal Combustion Engine using
ethanol as working fluid and a swash-plate expander as expansion machine.
The main objective of this research work is to obtain and quantify the
potential of Organic Rankine Cycles for the use of residual energy in
automotive engines. To do this, an experimental ORC test bench was
designed and built at CMT (Polytechnic University of Valencia), which can
be coupled to different types of automotive combustion engines. Using
these results, an estimation of the main variables of the cycle was obtained
both in stationary and transient operating points. A potential of increasing
ICE mechanical efficiency up to 3.7% could be reached at points of high
load installing an ORC in a conventional turbocharged gasoline engine.
Regarding transient conditions, a slightly simple and robust control based
on adaptive PIDs, allows the control of the ORC in realistic driving profiles.
High loads and hot conditions should be the starting ideal conditions to
test and validate the control of the ORC in order to achieve high exhaust
temperatures that justify the feasibility of the system.
In order to deepen in the viability and characteristics of this particular
application, some theoretical studies were done. A 1D model was developed
using LMS Imagine.Lab Amesim platform. A potential improvement
of 2.5% in fuel conversion efficiency was obtained at the high operating
points as a direct consequence of the 23.5 g/kWh reduction in bsfc. To
conclude, a thermo-economic study was developed taking into account
the main elements of the installation costs and a minimum Specific Investment
Cost value of 2030 €/kW was obtained. Moreover, an exergetic
study showed that a total amount of 3.75 kW, 36.5% of exergy destruction
rate, could be lowered in the forthcoming years, taking account the maximum
efficiencies considering technical restrictions of the cycle components. / Las normativas anticontaminantes para el transporte propulsado por
motores de combustión interna alternativos en la Unión Europea muestran
límites de emisión menores a 95 g CO2/km para el año 2020. Con el fin
de cumplir estos límites, deberán ser realizadas mejoras en el consumo
de combustible en los vehículos. Una de las principales pérdidas en los
Motores de Combustión Interna Alternativos (MCIA) ocurre en la línea de
escape. Los MCIA transforman la energía química en energía mecánica
a través de la combustión; sin embargo, únicamente el 15-32% de esta
energía es eficazmente usada para producir trabajo, mientras que la mayor
parte es desperdiciada a través de los gases de escape y el agua de refrigeración
del motor. Por ello, estas fuentes de energía pueden ser utilizadas
para mejorar la eficiencia global del vehículo. De estas fuentes, los gases de
escape muestran un potencial mayor de recuperación de energía residual
debido a su mayor contenido exergético. De todos los tipos de Sistemas de
Recuperación de Energía Residual, los Ciclos Rankine son considerados
como los candidatos más prometedores para mejorar la eficiencia de los
MCIA. Sin embargo, la implementación de esta tecnología en los vehículos
de pasajeros modernos requiere nuevas características para conseguir una
integración compacta y una buena controlabilidad del motor. Mientras que
las aplicaciones industriales normalmente operan en puntos de operación
estacionarios, en el caso de los vehículos con MCIA existen importantes
retos teniendo en cuenta su impacto en el modo de conducción cotidianos.
Esta Tesis contribuye al conocimiento y caracterización de un Ciclo
Rankine Orgánico acoplado con un Motor de Combustión Interna Alternativo
utilizando etanol como fluido de trabajo y un expansor tipo Swash-plate
como máquina expansora. El principal objetivo de este trabajo de investigación
es obtener y cuantificar el potencial de los Ciclos Rankine Orgánicos
(ORC) para la recuperación de la energía residual en motores de automoción.
Para ello, una instalación experimental con un Ciclo Rankine
Orgánico fue diseñada y construida en el Instituto Universitario "CMT -
Motores Térmicos" (Universidad Politécnica de Valencia), que puede ser
acoplada a diferentes tipos de motores de combustión interna alternativos.
Usando esta instalación, una estimación de las principales variables del
ciclo fue obtenida tanto en puntos estacionarios como en transitorios. Un
potencial de mejora en torno a un 3.7 % puede ser alcanzada en puntos
de alta carga instalando un ORC en un motor gasolina turboalimentado.
Respecto a las condiciones transitorias, un control sencillo y robusto basado
en PIDs adaptativos permite el control del ORC en perfiles de conducción
reales. Las condiciones ideales para testear y validar el control del ORC
son alta carga en el motor comenzando con el motor en caliente para conseguir
altas temperaturas en el escape que justifiquen la viabilidad de
estos ciclos.
Para tratar de profundizar en la viabilidad y características de esta
aplicación particular, diversos estudios teóricos fueron realizados. Un
modelo 1D fue desarrollado usando el software LMS Imagine.Lab Amesim.
Un potencial de mejora en torno a un 2.5% en el rendimiento efectivo del
motor fue obtenido en condiciones transitorias en los puntos de alta carga
como una consecuencia directa de la reducción de 23.5 g/kWh del consumo
específico. Para concluir, un estudio termo-económico fue desarrollado
teniendo en cuenta los costes de los principales elementos de la instalación
y un valor mínimo de 2030 €/kW fue obtenido en el parámetro de Coste
Específico de inversión. Además, el estudio exergético muestra que un total
de 3.75 kW, 36.5 % de la tasa de destrucción total de exergía, podría ser
reducida en los años futuros, teniendo en cuenta las máximas eficiencias
considerando restricciones técnicas en los componentes del ciclo. / Les normatives anticontaminants per al transport propulsat per motors
de combustió interna alternatius a la Unió Europea mostren límits
d'emissió menors a 95 g·CO2/km per a l'any 2020. Per tal d'acomplir aquests
límits, s'hauran de realitzar millores al consum de combustible dels
vehicles. Una de les principals pèrdues als Motors de combustió interna
alternatius (MCIA) ocorre a la línia d'escapament. Els MCIA transformen
l'energia química en energia mecànica a través de la combustió; però, únicament
el 15-32% d'aquesta energia és usada per produir treball, mentre que
la major part és desaprofitada a través dels gasos d'escapament i l'aigua
de refrigeració del motor. Per això, aquestes fonts d'energia poden ser
utilitzades per millorar l'eficiència global del vehicle. Considerant aquestes
dues fonts d'energia, els gasos d'escapament mostren un potencial major
de recuperació d'energia residual debut al seu major contingut exergètic.
De tots els tipus de Sistemes de Recuperació d'Energia Residual, els Cicles
Rankine són considerats com els candidats més prometedors per millorar
l'eficiència dels MCIA. No obstant, la implementació d'aquesta tecnologia
en els vehicles de passatgers moderns requereix un desenvolupament
addicional per aconseguir una integració compacta i una bona controlabilitat
del motor. Mentre que les aplicacions industrials normalment operen
en punts d'operació estacionaris, en el cas dels vehicles amb MCIA hi
han importants reptes a solucionar tenint en compte el funcionament en
condicions variables del motor i el seu impacte en la manera de conducció
quotidiana del usuari.
Aquesta Tesi contribueix al coneixement i caracterització d'un Cicle
Rankine Orgànic (ORC) acoblat amb un motor de combustió interna alternatiu
(MCIA) utilitzant etanol com a fluid de treball i un expansor tipus
Swash-plate com a màquina expansora. El principal objectiu d'aquest
treball de recerca és obtenir i quantificar el potencial dels ORCs per a la
recuperació de l'energia residual en motors d'automoció. Per aconseguir-ho,
una instal·lació experimental amb un ORC va ser dissenyada i construïda
a l'Institut "CMT- Motores Térmicos" (Universitat Politècnica de València).
Esta installació pot ser acoblada a diferents tipus de MCIAs. Mitjançant
assajos experimentals en aquesta installació, una estimació de les principals
variables del cicle va ser obtinguda tant en punts estacionaris com
en punts transitoris. Un potencial de millora al voltant d'un 3.7% pot ser
aconseguida en punts d'alta càrrega instal·lant un ORC acoblat a un motor
gasolina turboalimentat. Pel que fa a les condicions transitòries, un control
senzill i robust basat en PIDs adaptatius permet el control del ORC en
perfils de conducció reals. Les condicions ideals per a testejar i validar
el control de l'ORC són alta càrrega al motor començant amb el motor en
calent per aconseguir altes temperatures d'escapament que justifiquen la
viabilitat d'aquests cicles.
Per tractar d'aprofundir en la viabilitat i característiques d'aquesta
aplicació particular, diversos estudis teòrics van ser realitzats. Un model
1D va ser desenvolupat usant el programari LMS Imagine.Lab Amesim.
Un potencial de millora al voltant d'un 2.5% en el rendiment efectiu del
motor va ser obtingut en condicions transitòries en els punts d'alta càrrega
com una conseqüència directa de la reducció de 23.5 g/kWh al consum
específic. Per concloure, un estudi termo-econòmic va ser desenvolupat
tenint en compte els costos dels principals elements de la installació i
un valor mínim de 2030 €/kW va ser obtingut en el paràmetre del Cost
Específic d'Inversió. A més, l'estudi exergètic mostra que un total de 3.75
kW, 36.5% de la taxa de destrucció total d'exergia, podria ser recuperat en
un pròxim, considerant restriccions tècniques en els components del cicle i
tenint en compte les màximes eficiències que es poden aconseguir. / Royo Pascual, L. (2017). Study of Organic Rankine Cycles for Waste Heat Recovery in Transportation Vehicles [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84013 / TESIS
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System Simulation of Combustion in Direct-Injection Spark-Ignition Engines / Simulation système de la combustion dans les moteurs à allumage commandé à injection directePellegrino, Federico 17 October 2019 (has links)
La présence de contraintes de plus en plus strictes sur les émissions de polluants on poussé les contruteurs vers l'injection directe essence (IDE), afin d'améliorer les performances et réduire la consommation de carburant et les émissions des moteurs à combustion interne. Par conséquent, de nouveaux défis sont introduits en termes d'optimisation de la combustion, en raison d'une plus complexe phénomenologie tandis que les modéles système demande des paramètres de calibration supplémentaires.Cette thèse présente le développement et la validation d'un modèle zéro-dimensionnel (0D) de combustion en IDE pour application en simulation système. Le modèle proposé détaille la physique de l'atomisation, et évaporation des gouttes, de la préparation du mélange air/carburant, de la propagation de flamme dans un mélange non-homogène ainsi que l'intéraction entre ces phénomènes.La phase liquide est discretisés en paquets groupant des gouttes de la même taille.Un modèle d'atomisation empirique basé sur la vitesse d'injection, les propriétés du carburant et les conditions thermodynamiques fournit les diamètres initiaux. Un modèle Lagrangien détaillant une dynamique de trainée/inértie, échange thermique et convection forcée décrit la pénétration liquide et l'evaporation des paquets. La formation du mélange air/carburant est décrite avec une PDF qui discretise la charge en un mécanisme de classes intéragissant les unes avec les autres et avec les paquets de gouttes. La propagation de flamme prend en compte les effets de l'hétérogéneité du mélange sur la vitesse de flamme et la formation des polluants.Le modèle proposé a été implémenté dans la plateforme Simcenter Amesim, dédiée á la modélisation de systémes multi-physiques, et intégrée dans le modèle de combustion essence CFM1D, de la librairie IFP-Engine.Des approche de modélisation de l'evaporation de carburant, de la dynamique de spray et de la formation du mélange, inspirés de la literature sur les moteurs Diesel, ont été adaptés aux conditions IDE.Le modèle a initialement été validé sur des mesures et des simulations RANS 3D réalisées avec le code IFP-C3D, d'une bombe d'injection à volume constant.Un vortex de tumble, dans un premier temps, et des variations rapides du voulume de la chambre ensuite, ont été ajoutés aux expériments numériques afin d'évaluer la réponse du modèle à l'aérodynamique dans la chambre de combustion et à des conditions thermodynamiques variables, en termes d'évaporation, développement du spray et distribution de la richesse. Des simulations d'injections dans un moteur entraîné,dont les résultats ont été comparés avec des mesures et des calculs CDF,complètent la validation du modèle avec à la fois des conditions thermodynamiques variable et de l'aérodynamique. / Future constraints on pollutant emissions pushed car manufacturers towards gasoline direct injection (GDI) technologies to improve engine performances and reduce fuel consumption and emissions. New challenges are then introduced in terms of combustion optimization due to a more complex phenomenology while system models require additional calibration parameters.This PhD work presents the development and validation of a Zero-Dimensional (0D) model of GDI combustion for system simulation. The proposed model focuses on physics of atomization and drop evaporation, fuel/air mixing, flame propagation in heterogeneous charge and mutual interaction between these phenomena.The liquid phase is discretized in parcels grouping drops of the same size. An empirical atomization model based on injection velocity, fuel characteristics and thermodynamic conditions provides initial diameters. A Lagrangian model including drag-inertia dynamics, heat-up and forced convection describes drop parcel penetration and evaporation. Fuel / air mixing is described using a discrete Probability Density Function (PDF) approach, based on constant-mixture-fraction classes interacting with each other and with the drop parcels. Flame propagation takes into account mixture heterogeneity effects on flame speed and pollutant production is modelled.The model was implemented in the Simcenter Amesim platform for multi-physical modelling and integrated in a generic Spark Ignition (SI) combustion chamber submodel, CFM1D, from the IFP-Engine library.Fuel evaporation, spray dynamics and mixture formation modelling approaches, inspired by literature on Diesel engines, were adapted to GDI operating conditions. The model was first validated on a constant-volume vessel with quiescent gas in different thermodynamic conditions by means of experiments and 3D RANS CFD simulations performed with IFP-C3D. A tumble vortex in a constant volume vessel, in a first time, and rapid variations of the vessel volume, in a second time, were then added to the numerical experiment in order to test the model response to in-cylinder flow aerodynamics and variable thermodynamic conditions, respectively, in terms of fuel evaporation, spray development and fuel/air mixing and equivalence ratio distribution. Computations of fuel injections in a motored engine complete the model validation campaign in variable thermodynamic conditions and with realistic aerodynamics and the results were compared to both experiments and CFD computations.
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PRODUCTION OF HYDROCARBONS FROM PLANT OIL FOR RENEWABLE GASOLINE AND DIESEL FUELS / 再生可能ガソリン及びディーゼル燃料のための植物油からの炭化水素製造Kiky, Corneliasari Sembiring 24 September 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第22085号 / エネ博第393号 / 新制||エネ||76(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 河本 晴雄, 教授 石原 慶一, 教授 川那辺 洋 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM
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Model-Predictive Control of Gas Exchange in a Gasoline EngineJajji, George January 2021 (has links)
The process to induct air into engine cylinders, via the air inlet system and cylin-der port valves, is referred to as the "gas-exchange". Control is achieved by theturbo-charger, the intake throttle plate and the variable valve timing (VVT) sys-tem. These actuation systems traditionally use separate control with indepen-dent SISO feedback. There are however physical couplings that affect the con-trol performance. This thesis work looks at MPC control methods for a robustcontrol strategy. MPC methods are typically used for systems with slow dynam-ics, due to computational limits. But new advances in CPU performance shouldallow for real-time implementations for engine control. / <p>Redan framlagt exjobbet</p>
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