Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: CNG–DIESEL DUAL FUEL.
Rozprawy doktorskie na temat „CNG–DIESEL DUAL FUEL”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „CNG–DIESEL DUAL FUEL”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Königsson, Fredrik. "On Combustion in the CNG-Diesel Dual Fuel Engine". Doctoral thesis, KTH, Förbränningsmotorteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151188.
Pełny tekst źródłaStreszczenie:
Currently there is a large interest in alternative transport fuels. There are two underlying reasons for this interest: the desire to decrease the environmental impact of transports and the need to compensate for the declining availability of petroleum. In the light of both these factors, the CNG-diesel dual fuelengine is an attractive concept. The primary fuel of the dual fuel engine is methane, which can be derived both from renewables and from fossil sources. Methane from organic waste, commonly referred to as biomethane, can provide a reduction in greenhouse gases unmatched by any other fuel. Furthermore, fossil methane, natural gas, is one of the most abundant fossil fuels.Thedual fuelengine is, from a combustion point of view, a hybridof the diesel and theOtto-engineand it shares characteristics with both. From a market standpoint, the dual fuel technology is highly desirable; however, from a technical point of view it has proven difficult to realize. The aim of this project was to identify limitations to engine operation, investigate these challenges, and ,as much as possible, suggest remedies. Investigations have been made into emissions formation, nozzle-hole coking, impact of varying in-cylinder air motion, behavior and root causes of pre-ignitions, and the potential of advanced injection strategies and unconventional combustion modes. The findings from each of these investigations have been summarized, and recommendations for the development of a Euro 6 compliant dual fuel engine have been formulated. Two key challenges must be researched further for this development to succeed: an aftertreatment system which allows for low exhaust temperatures must be available, and the root cause of pre-ignitions must be found and eliminated.QQC 20140915
2
Königsson, Fredrik. "Advancing the Limits of Dual Fuel Combustion". Licentiate thesis, KTH, Förbränningsmotorteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96945.
Pełny tekst źródłaStreszczenie:
There is a growing interest in alternative transport fuels. There are two underlying reasons for this interest; the desire to decrease the environmental impact of transports and the need to compensate for the declining availability of petroleum. In the light of both these factors the Diesel Dual Fuel, DDF, engine is an attractive concept. The primary fuel of the DDF engine is methane, which can be derived both from renewables and from fossil sources. Methane from organic waste; commonly referred to as biomethane, can provide a reduction in greenhouse gases unmatched by any other fuel. The DDF engine is from a combustion point of view a hybrid between the diesel and the otto engine and it shares characteristics with both. This work identifies the main challenges of DDF operation and suggests methods to overcome them. Injector tip temperature and pre-ignitions have been found to limit performance in addition to the restrictions known from literature such as knock and emissions of NOx and HC. HC emissions are especially challenging at light load where throttling is required to promote flame propagation. For this reason it is desired to increase the lean limit in the light load range in order to reduce pumping losses and increase efficiency. It is shown that the best results in this area are achieved by using early diesel injection to achieve HCCI/RCCI combustion where combustion phasing is controlled by the ratio between diesel and methane. However, even without committing to HCCI/RCCI combustion and the difficult control issues associated with it, substantial gains are accomplished by splitting the diesel injection into two and allocating most of the diesel fuel to the early injection. HCCI/RCCI and PPCI combustion can be used with great effect to reduce the emissions of unburned hydrocarbons at light load. At high load, the challenges that need to be overcome are mostly related to heat. Injector tip temperatures need to be observed since the cooling effect of diesel flow through the nozzle is largely removed. Through investigation and modeling it is shown that the cooling effect of the diesel fuel occurs as the fuel resides injector between injections and not during the actual injection event. For this reason; fuel residing close to the tip absorbs more heat and as a result the dependence of tip temperature on diesel substitution rate is highly non-linear. The problem can be reduced greatly by improved cooling around the diesel injector. Knock and preignitions are limiting the performance of the engine and the behavior of each and how they are affected by gas quality needs to be determined. Based on experiences from this project where pure methane has been used as fuel; preignitions impose a stricter limit on engine operation than knock.QC 20120626
Diesel Dual Fuel
3
Park, Talus. "Dual fuel conversion of a direct injection diesel engine". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=460.
Pełny tekst źródłaStreszczenie:
Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 96 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 61-62).
4
CASADO, MAURICIO LADEIRA. "DEVELOPMENT OF A DIESEL-GAS MECHANICAL DUAL FUEL KIT". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7741@1.
Pełny tekst źródłaStreszczenie:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRONeste estudo foi desenvolvido um sistema de alimentação mecânico para conversão de um motor do ciclo Diesel para operar como um motor dual dieselgás natural, com campo de aplicação em embarcações fluviais de pequeno e médio porte. Primeiramente foram executados ensaios no modo original, diesel puro, e em seguida com controle manual de injeção diesel- gás. Os resultados experimentais foram utilizados para comparação entre os dois modos de operação e como base para elaboração do sistema de conversão reversível, sempre mantendo os mesmos níveis de torque e potência do motor. Numa segunda etapa criou-se uma metodologia para construção do sistema de controle de alimentação dual, para um regime de funcionamento simulando a operação do motor com uma hélice acoplada. O controle foi projetado, construído e montado no motor para realização dos testes de desempenho e validação do sistema. O motor foi testado novamente nos dois modos de operação e os resultados comparados em termos de desempenho global, eficiência e nível de emissões (particulados). Os resultados obtidos confirmam a viabilidade econômica e técnica de se operar o motor no modo dual com os mesmos níveis de torque e potência do motor diesel original e validaram o sistema de controle projetado. Foram observadas reduções significativas das emissões (particulados) com um rendimento satisfatório para todo o regime de operação avaliado. As taxas de substituição (diesel-gás) impostas são da ordem de 70%, limitadas pelo sistema de controle, para minimizar os riscos de possíveis danos ao motor em termos de superaquecimento dos bicos injetores e pela detonação.
In this work a mechanical system of fuel supply was developed to convert a Diesel engine for dual fuel diesel-gas Dual operation in small and medium size fluvial boats. First assays, in the original way, pure diesel operation had been executed. After that, the dual fuel operation was conducted with manual control of diesel and gas injection. The experimental results had been used for comparison between the two ways of operation and as a base line for elaboration of the system of reversible conversion, always keeping the same levels of torque and power of the engine. In a second stage, a methodology for construction of the system of control for dual fuel supplying was created. A specific curve of functioning, simulating the operation of the engine connected to a propeller, was used for that. The control was projected, constructed and adapted in the engine for the realization of performance tests and system validation. The engine was tested again in the two modes of operation and the results compared in terms of overall performance, efficiency and emission levels (particulates). The acquired results confirm the economic viability and technique of the dual fuel operation of the engine with the same levels of torque and power of the original diesel engine, validating the projected system of control. Significant reductions of the emissions (particulates) with a satisfactory performance for all the evaluated points of operation was observed. The imposed substitution (diesel-gas) rate is around 70%, limited by the control system, to minimize the risks of possible damages to the engine in terms of overheating of the injector atomizers and knocking occurrence.
5
MOUTELLA, FELIPE LEAL DA COSTA. "NUMERICAL SIMULATION OF DUAL-FUEL DIESEL-NATURAL GAS ENGINES". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15407@1.
Pełny tekst źródłaStreszczenie:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROA adaptação de um simulador numérico para a simulação da operação bicombustível Diesel-gás em motores com ignição por compressão foi realizada. O código-fonte em questão foi desenvolvido ao longo dos últimos anos pelo IFP, e uma modificação ao modelo da auto-ignição nele contido foi concluída neste estudo. As diversas etapas necessárias para a adaptação são apresentadas. Considerações foram feitas em relação à literatura existente para o assunto, e as hipóteses realizadas foram verificadas numericamente sempre que possível. Uma equação que relaciona os números de octanas do Diesel e do gás natural com a qualidade da auto-ignição de sua combinação resultante é proposta. Foi construída uma extensa base de dados necessária ao funcionamento do modelo, contendo as taxas de reação em função dos parâmetros físicos da mistura. Por fim, foi feita uma análise qualitativa de simulações bicombustível para um motor Diesel.
The adaptation of a numerical simulator for the dual fuel Diesel-gas combustion in compression ignition engines was accomplished. The referred source code has been developed for the past years by the IFP, and a modification of its auto-ignition model was concluded during this study. The various steps needed for this adaptation are presented. All hypotheses were numerically verified when possible. A relation between auto-ignition quality and the combination of the octane numbers of Diesel and natural gas is proposed. A comprehensive reaction rates database required by the model was constructed. Finally, a qualitative analysis of dual fuel simulations in a Diesel engine was conducted.
6
FILHO, FERNANDO FERRARI. "EVALUATION OF DIESEL CYCLE ENGINE OPERATING IN THE DUAL FUEL MODE: DIESEL / ETHANOL". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19636@1.
Pełny tekst źródłaStreszczenie:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROEste trabalho avaliou o comportamento de um motor do ciclo Diesel, operando no modo original (Diesel puro) e no modo bicombustível (Diesel / etanol), em dois modos de hidratação do álcool (70 e 93 graus INPM). A rotação foi mantida fixa em 1800 rpm. A finalidade foi estudar os parâmetros de desempenho do motor e analisar a liberação de calor pela combustão, como também, o calor trocado com as paredes. Avaliou-se como parâmetros de desempenho, o rendimento térmico, consumo específico de combustível e emissão de poluentes. A fase inicial do trabalho constou de ensaios experimentais realizados no conjunto motor / dinamômetro nos modos mencionados acima. O objetivo foi coletar a variação de pressão no interior do cilindro, consumo de combustível, emissão de gases, temperaturas em pontos estratégicos, entre outros. Em uma segunda etapa foi realizada uma análise dos parâmetros de desempenho e da liberação de calor. Para emissões de poluentes, observou-se uma diminuição de MP em altas taxas de substituição. No entanto, notou-se um aumento elevado de HC. Em baixas cargas e taxas de substituição elevadas houve redução de emissão de NOx. O rendimento térmico apresentou comportamentos similares em 70 e 93 graus INPM. Em altas cargas e altas taxas de substituição houve um sensível aumento do rendimento quando comparado ao modo original. O rendimento foi menor para baixas cargas com altas taxas de substituição, em relação ao modo original. O início da combustão no modo bicombustível foi antecipado em relação ao modo original, nas condições de altas cargas e máximas taxas de substituição. Isto foi devido à liberação de calor que ocorreu mais cedo no modo bicombustível. Ressalta-se que, nas mesmas condições, houve a ocorrência de um maior calor trocado com as paredes do cilindro, em ambos os modos de hidratação (70 – 93 graus INPM), quando comparado ao modo original.
This work aimed to evaluate a Diesel cycle engine operating in the original (only Diesel) and dual-fuel modes (Diesel / ethanol) in two levels of hydration of alcohol (70 and 93 degrees INPM). Speed was kept fixed at 1800 rpm. The purpose was to study the parameters of engine performance and analyze the heat release by combustion and heat exchanged to the cylinder’s walls. For parameters of performance, evaluation of thermal efficiency, specific fuel consumption and emissions were conducted. Initial activities consisted in trial tests on the engine / dynamometer in the two modes as mentioned above. The goal was to collect the variation of indicated cylinder pressure data, as well as fuel consumption, emissions and temperatures at strategic points. Secondly, performance parameters and heat release analysis was performed. For emissions, a decrease in PM was found at higher replacement rates; however, in the same condition a large increase in HC was obtained. At low loads and at higher replacement rates, NOx emissions were reduced. Thermal efficiency showed similar behavior at 70 and 93 degrees INPM. At high loads and at higher replacement rates a significant increase in thermal efficiency compared to the original mode and for low loads with higher replacement rates thermal efficiency was decreased. In high loads and at higher replacement rates conditions, the process of combustion occurred before in the dual fuel mode, due to earlier heat release compared to original mode (only Diesel). In the same conditions an increase of heat exchanged to the cylinder’s wall in both modes of hydration of alcohol (70 and 93 degrees INPM) compared to the original mode was obtained.
7
Júnior, Roberto Freitas Britto. "Experimental analysis of a diesel engine operating in diesel-ethanol dual-fuel mode". Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3043.
Pełny tekst źródłaStreszczenie:
A significant part of the world economy depends on stationary or vehicular Diesel engines. Such engines are fed mainly by fossil fuels, among these, the standard diesel. The growing interest in renewable energy sources makes the use of ethanol in these engines a real technological demand. From the existing concepts to meet this goal the Diesel-Ethanol in the Dual-Fuel mode has demand for published experimental data. Such concept brings a greater degree of freedom, but implications in technological challenges. It works through a PFI (Port Fuel Injection) system to prepare a pre-mixture of air and ethanol in the intake port which is compressed in the combustion chamber and ignited by pilot injection of diesel. In this work a single cylinder research engine with 100% electronically controlled calibration was used. The engine control parameters were set to maximize diesel substitution rate by ethanol with a limited indicated efficiency loss. Comparisons were made among different working conditions. Initially, the flow structure in the combustion chamber was tested in both quiescent and high swirl modes. Compression ratios were adjusted at 3 different levels: 14:1, 16:1 and 17:1. Two injectors were tested, the first one with mass flow of 35 g/s and another of 45 g/s. Regarding pressure diesel injection, 4 levels were investigated namely 800, 1000, 1200 and 1400 bar. The experiments discussed in this work were able to achieve up to 65% of diesel energy substituted by hydrated ethanol energy with an indicated efficiency of 49%. In comparison with the diesel only running condition, the NOx emissions was improved by up to 60%. But the HC, CO and aldehydes emissions had a penalty, showing a trade-off that shall be further investigated with a final design engine in the beginning of product development process.
8
EGUSQUIZA, JULIO CESAR CUISANO. "EXPERIMENTAL INVESTIGATION OF A DIESEL CYCLE ENGINE OPERATING ON DUAL-FUEL MODE: DIESEL / ETHANOL AND DIESEL / GAS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=17103@1.
Pełny tekst źródłaStreszczenie:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRONo presente trabalho, ensaios experimentais de um motor do ciclo Diesel consumindo etanol hidratado ou gás natural em substituição parcial ao óleo diesel, foram realizados. Os objetivos principais foram verificar as influências dos combustíveis alternativos e avaliar as técnicas do avanço da injeção do diesel e da restrição parcial do ar de admissão, em relação aos parâmetros característicos da combustão, desempenho e emissões. Com base nos dados do diagrama pressão-ângulo de virabrequim, foi possível analisar alguns parâmetros característicos da combustão, tais como o início da combustão, a máxima taxa de elevação de pressão e o pico de pressão. Os parâmetros do desempenho e emissões do motor foram analisados através do rendimento térmico e as concentrações de monóxido de carbono, hidrocarbonetos, material particulado e óxidos de nitrogênio. Os resultados obtidos mostraram que as técnicas avaliadas no modo bicombustível junto com as elevadas taxas de substituição do óleo diesel favoreceram a melhor queima dos combustíveis alternativos, refletindo-se favoravelmente em menores emissões de CO e MP, além de um pequeno aumento no rendimento térmico do motor. No entanto, houve também um acréscimo nas emissões de NOX e, no caso específico do avanço da injeção, foi notado um maior ruído gerado pelo motor.
In this report, experimental tests of a Diesel cycle engine running with hydrous ethanol or natural gas with partial substitution for diesel fuel were performed. The main objectives were to verify the influence of alternative fuels and evaluate the advancing of diesel injection timing and the air partial restriction, regarding the characteristic parameters of combustion, performance and emissions. Based on data from the pressure-crank angle diagram, it was possible to analyze some characteristic parameters of combustion, such as the start of combustion, the maximum rate of pressure rise and peak pressure. The parameters of the engine performance and emissions were analyzed through the thermal efficiency and the concentrations of carbon monoxide, hydrocarbons, particulate matter and nitrogen oxides. The results showed that the techniques evaluated in dual fuel mode with higher rates of substitution of diesel fuel favored a better burning of the alternative fuels, reflecting favorably in lower emissions of CO and PM, and also in a small increase in the engine thermal efficiency. However, there was also an increase in NOX emissions and, in the specific case of the advanced injection timing, it was noted a louder noise generated by the engine.
9
Mirmohammadsadeghi, Mahmoudreza. "Investigation of diesel-ethanol and diesel-gasoline dual fuel combustion in a single cylinder optical diesel engine". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17436.
Pełny tekst źródłaStreszczenie:
Ever growing population and increased energy consumption across all industries has resulted in higher atmospheric concentration of the greenhouse gases (GHG) and therefore an increase in the planet's average temperature, which has led to increasingly demanding and more strict legislations on pollutant sources, and more specifically, the automotive industry. As a consequence of all this, the demand for research into alternative energy sources has greatly increased. In this study combustion characteristics, engine performance, and exhaust emission of diesel-ethanol and diesel-gasoline are investigated in an optical direct injection diesel engine. In particular, effects of different substitution ratios and diesel injection strategies are studied when the total fuel energy is kept constant. The three main substitution ratios used in this study include 45% (45% of fuel energy from port-injected ethanol/gasoline and 55% from direct injection diesel), 60%, and 75%. The engine used for this investigation is a Ricardo Hydra single cylinder optical engine running at 1200 rpm. In-cylinder pressure measurement is used for calculating all engine parameters, heat release rate, and efficiency. In addition to the thermodynamic analysis of the combustion parameters, high speed camera was used alongside with a copper vapor laser or the high speed image intensifier in the high speed video imaging for the optical analysis of the effect of the above-mentioned parameters on autoignition and combustion processes, while Horiba particulate analyser and AVL smoke meter were utilized in monitoring and recording emissions for every tested condition. Depending on the testing conditions, such as injection strategy and intake conditions, both dual-fuel operations were able to deliver high efficiency and improved emissions compared to that of a pure diesel engine operation, with the diesel-gasoline operation offering more consistency in improved thermal efficiency, and the diesel-ethanol operation delivering lower emission output. The optical analysis of the combustion represents the main difference in the flame propagation, distribution and quality for each substitute fuel and its substitution percentage, as well as the condition under examination.
10
Belizário, Adenilson Cristiano. "Avaliação da confiabilidade do motor diesel com a adição de sistemas de injeção de gás na câmara de combustão". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-24092012-171716/.
Pełny tekst źródłaStreszczenie:
Visando a redução de poluentes emitidos pelos motores de combustão interna com ignição por compressão, que operam conforme o ciclo diesel, foram desenvolvidos nos últimos anos dispositivos para a operação destes motores com novos combustíveis, que além da redução de poluentes barateariam o custo de operação, devido à oportunidade de utilização de alguns combustíveis com boa disponibilidade. No presente estudo analisa-se a operação do motor diesel utilizando gás natural como combustível. Neste caso utiliza-se o óleo diesel apenas como combustível piloto, que será responsável pela ignição do segundo combustível, o gás natural. Em diversas publicações constata-se o ganho ambiental e econômico desta aplicação, porém nada é comentado em relação à alteração de índices de confiabilidade e surgimento de novos modos de falha. Neste trabalho verifica-se através de ferramentas de análise de confiabilidade, tais como a análise do tipo FMEA e Árvore de falhas, quais os principais modos de falha que serão inseridos no motor de combustão interna do tipo diesel quando este passa a operar como bi-combustível, com gás natural. Para tanto, necessita-se subdividir o motor diesel em subsistemas mostrando sua estruturação em árvores funcionais e integrando o kit diesel gás neste sistema. A partir da análise de confiabilidade verifica-se a probabilidade de ocorrência de novos modos de falha, que necessitarão da elaboração de novos planos de manutenção ou mesmo alterações no projeto do subsistema de injeção de gás natural.In order to reduce pollutants emissions from internal combustion engines with compression bend ignition, designed to operate as the Diesel cycle, it has been developed in recent years devices for the addition of new fuels, which in addition to reducing pollutants could lower the cost of operation, due to the possibility of use of some fuels with good availability. In this case it is used only the diesel oil as the pilot flame, which is responsible for the ignition of the second fuel, the natural gas. Many publications discuss the environmental and the economic gain with the use of natural gas as fuel application, however nothing is said about the change of reliability indexes and the appearance of new failure modes in the engine. In this study through system reliability analysis tools such as Faillure Mode Effects and Analisys and Fault tree analysis it is analysed, which are the main failure modes that are inserted into the internal combustion engine when it comes to operate as dual fuel. For that analyses it is necessary to split the engine into subsystems showing its functional trees and integrating diesel gas kit in this system. New failure modes appear with greater severity than the existing in the traditional diesel engine system, leading to new design and maintenance practices. The end user, according to his need, will have one more parameter to choose whether to adopt a Diesel Gas system.
11
Broman, Robert, i Karl Rosenlind. "ESC-analys och studering av knack på en "Diesel Dual Fuel"-motor". Thesis, KTH, Maskinkonstruktion (Inst.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99784.
Pełny tekst źródłaStreszczenie:
A one-cylinder research engine has been used for studies with a Diesel Dual Fuel concept (DDF). DDF is a concept that utilizes a pilot diesel injection to ignite a homogenous natural gas/air mixture. Emissions and engine efficiency have been analyzed in an emission cycle called European Stationary Cycle (ESC) and the knock/pre-ignition problems with this type of engine have been investigated. At low and mid torque levels, an early diesel injection around 60 crank angles degrees (CAD) before top dead center (TDC) was used. At these loads raw NO xemissions was below EURO 6 level (0.2 g/kWh). NOxwas at EURO 5 level over the complete ESC without after treatment and with SCR at high loads it should be possible to reach EURO 6. One issue with DDF is the high HC emission levels. HC was approximately 40 g/kWh without after-treatment and by using an oxidation catalyst it should be lowered to around 10 g/kWh (approximated based on exhaust temperatures). Engine efficiency based on fuel flows and brake torque was within 26 - 40 % at different engine speeds and torque levels, which was lower than the same engine running with only diesel. The lower efficiency can be explained with the high amount of unburned hydrocarbons. Knock and pre-ignition was a problem at high loads and at medium loads when early diesel injection was used. The knock problems with this concept were highly dependent on the intake air temperature. Methods to avoid knock were tested. One way was to move the diesel injection a couple of CAD later. This was only applicable during the first knock cycles since several knock cycles in a row heated up the combustion chamber too much. Adding (more) EGR was also a good method to avoid knock.En encylindrig forskningsmotor har använts till att testa ett Diesel Dual Fuel-koncept (DDF) som ska fungera som en ‖retro fit‖-lösning. Med Diesel Dual Fuel menas att en dieselinsprutning används som tändkälla för att antända en homogen blandning av naturgas och luft. Emissioner och verkningsgrad har analyserats i en emissionscykel kallad European Stationary Cycle (ESC) samt problem med knack och pre-ignition har undersökts. På låg- och mellanlast användes en tidig dieselinsprutning runt 60 vevvinkelgrader före övre dödpunkt (ÖD). På dessa laster låg råemissionerna av NOx under ‖EURO 6‖-nivå (0.2 g/kWh). Över hela ESC-cykeln låg NOx på ‖EURO 5‖-nivå utan efterbehandling och med Selective Catalytic Reduction (SCR) på högre laster finns potential att uppnå ‖EURO 6‖. Ett stort problem med DDF är HC- emissionerna. Utan efterbehandling blev HC ca 40 g/kWh och med oxidationskatalysator skulle det vara möjligt att nå ca 10 g/kWh (uppskattades mha. avgastemperaturer). Motorns verkningsgrad beräknades utifrån bränsleflöden och utgående moment och låg mellan 26 - 40 % beroende på varvtal och last, vilket är lägre än för samma motor vid ren dieseldrift. Den lägre verkningsgraden förklarades med den stora mängden oförbrända kolväten. Knack och pre-ignition har visat sig vara problem med DDF-motorer på hög last samt även vid mellanlast då en tidig insprutning av dieseln användes. Det har visat sig att det här förbränningskonceptet är väldigt känsligt för luftens insugstemperatur. Metoder för att ta sig ur knack har testats i det här arbetet. Det snabbaste och enklaste har varit att flytta dieselinsprutningen några grader senare, men det fungerar endast efter ett fåtal knackcykler då förbränningsrummet värms upp mycket efter många knackcykler i rad. En annan bra metod för att gå ur knack var att tillsätta (mer) EGR.
12
Zastavniouk, Oleg. "Study of mixing phenomena in a dual fuel diesel engine air intake manifold". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq22695.pdf.
Pełny tekst źródła
13
Kersting, Lee Allan. "Characterizing the operation of a dual-fuel diesel-hydrogen engine near the knock limit". Thesis, North Dakota State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1568051.
Pełny tekst źródłaStreszczenie:
A CAT C6.6 turbocharged diesel engine was operated in dual-fuel diesel-hydrogen mode. Hydrogen was inducted into the intake and replaced a portion of the diesel fuel. Hydrogen was added across multiple engine speeds and loads until reaching the knock limit, identified by a threshold on the rate of in-cylinder pressure rise. In-cylinder pressure and emissions data were recorded and compared to diesel-only operation. Up to 74% H2 substitution for diesel fuel was achieved. Hydrogen addition increased thermal efficiency up to 32.4%, increased peak in-cylinder pressure up to 40.0%, increased the maximum rate of pressure rise up to 281%, advanced injection timing up to 13.6°, increased NOx emissions up to 224%, and reduced CO 2 emissions up to 47.6%. CO and HC emissions were not significantly affected during dual-fuel operation. At 25% load an operating condition was observed with low NOx and nearly 0 CO2 emissions, which however exhibited unstable combustion.
14
Kersting, Lee. "Characterizing the Operation of a Dual-Fuel Diesel-Hydrogen Engine near the Knock Limit". Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27572.
Pełny tekst źródłaStreszczenie:
A CAT C6.6 turbocharged diesel engine was operated in dual-fuel diesel-hydrogen mode. Hydrogen was inducted into the intake and replaced a portion of the diesel fuel. Hydrogen was added across multiple engine speeds and loads until reaching the knock limit, identified by a threshold on the rate of in-cylinder pressure rise. In-cylinder pressure and emissions data were recorded and compared to diesel-only operation. Up to 74% H2 substitution for diesel fuel was achieved. Hydrogen addition increased thermal efficiency up to 32.4%, increased peak in-cylinder pressure up to 40.0%, increased the maximum rate of pressure rise up to 281%, advanced injection timing up to 13.6?, increased NOx emissions up to 224%, and reduced CO2 emissions up to 47.6%. CO and HC emissions were not significantly affected during dual-fuel operation. At 25% load an operating condition was observed with low NOx and nearly 0 CO2 emissions, which however exhibited unstable combustion.
15
Reiter, Aaron Jesse. "Combustion and emissions characteristics of a compression-ignition engine using dual ammonia-diesel fuel". [Ames, Iowa : Iowa State University], 2009.
Znajdź pełny tekst źródła
16
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.
Pełny tekst źródłaStreszczenie:
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
TESIS
17
May, Ian Alexander. "An experimental investigation of lean-burn dual-fuel combustion in a heavy duty diesel engine". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16398.
Pełny tekst źródłaStreszczenie:
Natural gas is currently an attractive substitute for diesel fuel in the Heavy-Duty (HD) diesel transportation sector. This is primarily attributed to its cost effectiveness, but also its ability to reduce the amount of CO2 and harmful engine pollutants emitted into the atmosphere. Lean-burn dual-fuel engines substitute natural gas in place of diesel but typically suffer from high engine-out methane (CH4) emissions, particularly under low load operation. In response to this issue, this work set out to improve upon the efficiency and emissions of a lean-burn dual-fuel combustion system in an HD diesel/natural gas engine. Thermodynamic experimental engine testing was performed at various steady-state operating points in order to identify the most effective methods and technologies for improving emissions and efficiency. Low Temperature Combustion (LTC) along with several valvetrain and injection strategies were evaluated for benefits, with special attention paid to low load operating conditions. LTC was proven to be a useful method for decreasing methane emissions while simultaneously improving engine efficiency. The benefits of LTC were a function of load with the greatest advantages experienced under medium load operation. Additionally, the low load strategies tested were determined to be effective techniques for reducing methane emissions and could possibly extend the dual-fuel operating regime to lighter load conditions. Overall, no operating condition tested throughout the engine map resulted in a brake engine-out methane emissions level of less than 0.5 g/kWh at gas substitutions greater than approximately 75%. It is suggested that the limits of this particular lean-burn dual-fuel design were reached, and that it would likely require improvements to either the combustion system or exhaust after-treatment if Euro VI emissions levels for methane were to be achieved.
18
Hockett, Andrew. "A computational and experimental study on combustion processes in natural gas/diesel dual fuel engines". Thesis, Colorado State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=3746141.
Pełny tekst źródłaStreszczenie:
Natural gas/diesel dual fuel engines offer a path towards meeting current and future emissions standards with lower fuel cost. However, numerous technical challenges remain that require a greater understanding of the in-cylinder combustion physics. For example, due to the high compression ratio of diesel engines, substitution of natural gas for diesel fuel at high load is often limited by engine knock and pre-ignition. Additionally, increasing the natural gas percentage in a dual fuel engine often results in decreasing maximum load. These problems limit the substitution percentage of natural gas in high compression ratio diesel engines and therefore reduce the fuel cost savings. Furthermore, when operating at part load dual fuel engines can suffer from excessive emissions of unburned natural gas. Computational fluid dynamics (CFD) is a multi-dimensional modeling tool that can provide new information about the in-cylinder combustion processes causing these issues.
In this work a multi-dimensional CFD model has been developed for dual fuel natural gas/diesel combustion and validated across a wide range of engine loads, natural gas substitution percentages, and natural gas compositions. The model utilizes reduced chemical kinetics and a RANS based turbulence model. A new reduced chemical kinetic mechanism consisting of 141 species and 709 reactions was generated from multiple detailed mechanisms, and has been validated against ignition delay, laminar flame speed, diesel spray experiments, and dual fuel engine experiments using two different natural gas compositions. Engine experiments were conducted using a GM 1.9 liter turbocharged 4-cylinder common rail diesel engine, which was modified to accommodate port injection of natural gas and propane. A combination of experiments and simulations were used to explore the performance limitations of the light duty dual fuel engine including natural gas substitution percentage limits due to fast combustion or engine knock, pre-ignition, emissions, and maximum load. In particular, comparisons between detailed computations and experimental engine data resulted in an explanation of combustion phenomena leading to engine knock in dual fuel engines.
In addition to conventional dual fuel operation, a low temperature combustion strategy known as reactivity controlled compression ignition (RCCI) was explored using experiments and computations. RCCI uses early diesel injection to create a reactivity gradient leading to staged auto-ignition from the highest reactivity region to the lowest. Natural gas/diesel RCCI has proven to yield high efficiency and low emissions at moderate load, but has not been realized at the high loads possible in conventional diesel engines. Previous attempts to model natural gas/diesel RCCI using a RANS based turbulence model and a single component diesel fuel surrogate have shown much larger combustion rates than seen in experimental heat release rate profiles, because the reactivity gradient of real diesel fuel is not well captured. To obtain better agreement with experiments, a reduced dual fuel mechanism was constructed using a two component diesel surrogate. A sensitivity study was then performed on various model parameters resulting in improved agreement with experimental pressure and heat release rate.
19
Bianchi, Zarco. "Sviluppo ed analisi di un sistema dual-fuel diesel/benzina per combustioni di tipo RCCI". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8571/.
Pełny tekst źródłaStreszczenie:
Nel presente lavoro è progettato e sviluppato un sistema dual-fuel diesel/benzina per combustioni di tipo RCCI, e sono esposti i risultati sperimentali in termini di prestazioni ed emissioni. E' inoltre descritto e implementato un algoritmo di stima dell'MFB50 a partire dalla sola misura della velocità motore.
20
Bernardes, Pedrozo Vinícius. "An experimental study of ethanol-diesel dual-fuel combustion for high efficiency and clean heavy-duty engines". Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15850.
Pełny tekst źródłaStreszczenie:
Higher atmospheric concentration of greenhouse gases (GHG) such as carbon dioxide and methane has contributed to an increase in Earth's mean surface air temperature and caused climate changes. This largely reflects the increase in global energy consumption, which is heavily dependent on oil, natural gas, and coal. If not controlled, the combustion of these fossil fuels can also produce high levels of nitrogen oxides (NOx) and soot emissions, which adversely affect the air quality. New and extremely challenging fuel efficiency and exhaust emissions regulations are driving the development and optimisation of powertrain technologies as well as the use of low carbon fuels to cost-effectively meet stringent requirements and minimise the transport sector's GHG emissions. In this framework, the dual-fuel combustion has been shown as an effective means to maximise the utilisation of renewable liquid fuels such as ethanol in conventional diesel engines while reducing the levels of NOx and soot emissions. This research has developed strategies to optimise the use of ethanol as a substitute for diesel fuel and improve the effectiveness of dual-fuel combustion in terms of emissions, efficiency, and engine operational cost. Experimental investigations were performed on a single cylinder heavy-duty diesel engine equipped with a high pressure common rail injection system, cooled external exhaust gas recirculation, and a variable valve actuation system. A port fuel injection system was designed and installed, enabling dual-fuel operation with ethanol energy fractions up to 0.83. At low engine loads, in-cylinder control strategies such as the use of a higher residual gas fraction via an intake valve re-opening increased the combustion efficiency (from 87.7% to 95.9%) and the exhaust gas temperature (from 468 K to 531 K). A trade-off between operational cost and NOx reduction capability was assessed at medium loads, where the dual-fuel engine performance was less likely to be affected by combustion inefficiencies and in-cylinder pressure limitations. At high load conditions, a Miller cycle strategy via late intake valve closing decreased the in-cylinder gas temperature during the compression stroke, delaying the autoignition of the ethanol fuel and reducing the levels of in-cylinder pressure rise rate. This allowed for the use of high ethanol energy fractions of up to 0.79. Finally, the overall benefits and limitations of optimised ethanol-diesel dual-fuel combustion were compared against those of conventional diesel combustion. Higher net indicated efficiency (by up to 4.4%) combined with reductions in NOx (by up to 90%) and GHG (by up to 57%) emissions can help generate a viable business case of dual-fuel combustion as a technology for future high efficiency and clean heavy-duty engines.
21
Boccadamo, Danilo. "Analisi preliminare di combustioni innovative su un motore diesel di piccola cilindrata". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7288/.
Pełny tekst źródłaStreszczenie:
Analisi delle emissioni di inquinanti per combustioni innovative Dual-Fuel e Premixed Charge Compression Ignition (PCCI) operate su un motore Diesel, nel laboratorio di propulsione e macchine della Scuola d'Ingegneria e Architettura con sede a Forlì. Tale studio è stato realizzato in quanto la riduzione delle emissioni e dei consumi sono caratteristiche di primo impatto per la competitività sul mercato di un motore e poiché le emissioni di inquinanti sono regolate da standard europei che ne esigono la continua riduzione. L'obiettivo della ricerca è quello di definire un pattern di combustioni, variando il valore e la sincronizzazione dei parametri delle attuazioni, che consenta la riduzione di inquinanti senza compromettere le prestazioni. Capire come ottenere minori emissioni di inquinanti significa poter far rientrare anche i motori diesel nelle future normative EURO 6 (già definite ed in vigore da Settembre 2014), e di seguire studi paralleli sulla riduzione dei consumi sui quali sono già stati riscontrati risultati positivi.
22
Rosa, Josimar Souza. "Estudo de um motor ciclo diesel monocilíndrico bi-combustível". Universidade do Vale do Rio dos Sinos, 2014. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3459.
Pełny tekst źródłaStreszczenie:
Submitted by Maicon Juliano Schmidt (maicons) on 2015-05-07T16:35:35Z
No. of bitstreams: 1
Josimar Souza Rosa.pdf: 2316699 bytes, checksum: 10b8be8bf5285234719e629c53ebeb82 (MD5)Made available in DSpace on 2015-05-07T16:35:35Z (GMT). No. of bitstreams: 1 Josimar Souza Rosa.pdf: 2316699 bytes, checksum: 10b8be8bf5285234719e629c53ebeb82 (MD5) Previous issue date: 2014-03-21
Nenhuma
Este trabalho buscou analisar o funcionamento de um motor de combustão interna (ciclo Diesel) operando com misturas parciais de óleo diesel com gás natural veicular, e óleo de soja com gás natural veicular. Os ensaios foram realizados em um motor Agrale modelo M90, monocilíndrico, acoplado a um alternador, tendo como carga um banco de resistências. A análise realizada contemplou o desempenho em termos de consumo de combustível, potência e emissões gasosas de óxidos de nitrogênio, dióxidos de enxofre, monóxido de carbono, entre outros gases, bem como a análise da opacidade da fumaça. Os resultados mostraram que é viável a utilização de gás natural em motores ciclo Diesel sem remoção do sistema de injeção de diesel original, representando uma considerável redução nas emissões específicas dos óxidos de nitrogênio, sem perda de potência, porém resultando em combustão incompleta em altos percentuais de substituição de combustível líquido por gasoso. De maneira geral o melhor resultado em relação à eficiência foi possível com percentual de substituição de 43,7% de diesel por gás natural, no qual o conjunto motor gerador apresentou rendimento aproximado de 33,17%. A opacidade da fumaça emitida pelo motor foi reduzida significativamente quando funcionou em modo bi-combustível tanto com diesel e gás natural como óleo de soja e gás natural.
This study aims to analyze the operation of an internal combustion engine (diesel cycle) with partial mixtures of diesel oil and natural gas, and oil vegetable soybean and natural gas. The tests were carry in an engine Agrale model M90, monocilynder, coupled to alternator, and which charged a bank of resistors load. The analyses include performance fuel consumption, power and gas emissions of nitrogen oxides, sulfur dioxides, carbon monoxide, and other gases, as well the analysis of the smoke opacity. Results showed that it is feasible to use natural gas in diesel cycle engines without removing the original diesel injection system, generating a considerable reduction in specific emissions of nitrogen oxides, without loss of Power, but resulting in incomplete combustion at high percentages replacement of liquid fuel for natural gas. Generally, the Best result for efficiency was possible with replacement percentage of 43,7% of diesel per natural gas, when the generation setting showed efficiency equal at 33,17%. The smoke opacity was reduced significantly when operated in dual fuel both diesel and natural gas as soybean oil and natural gas.
23
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.
Pełny tekst źródłaStreszczenie:
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.
24
Sohail, Aamir. "An experimental investigation of dual-injection strategies on diesel-methane dual-fuel low temperature combustion in a Single Cylinder Research Engine". Thesis, Mississippi State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596101.
Pełny tekst źródłaStreszczenie:
The present manuscript discusses the performance and emission benefits due to two diesel injections in diesel-ignited methane dual fuel Low Temperature Combustion (LTC). A Single Cylinder Research Engine (SCRE) adapted for diesel-ignited methane dual fuelling was operated at 1500 rev/min and 5 bar BMEP with 1.5 bar intake manifold pressure. The first injection was fixed at 310 CAD. A 2nd injection sweep timing was performed to determine the best 2nd injection timing (as 375 CAD) at a fixed Percentage Energy Substitution (PES 75%). The motivation to use a second late injection ATDC was to oxidize Unburnt Hydrocarbons (HC) generated from the dual fuel combustion of first injection. Finally, an injection pressure sweep (550-1300 bar) helped achieve simultaneous reduction of HC (56%) and CO (43%) emissions accompanied with increased IFCE (10%) and combustion efficiency (12%) w.r.t. the baseline single injection (at 310 CAD) of dual fuel LTC.
25
Yeo, Jeff. "Development and application of in-cylinder fuel concentration and pyrometry optical diagnostic tools in diesel-ignited dual-fuel natural gas engines". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62716.
Pełny tekst źródłaStreszczenie:
In recent years, government policies have mandated significant reductions in emissions of greenhouse gases (GHG) and particulate matter (PM) from heavy-duty, on-highway transportation applications. This has necessitated the development of clean engine technologies such as dual-fuel combustion of natural gas (NG) in compression ignition (CI) engines. With these new engine developments, the need to understand and optimize these technologies to meet emission regulations becomes crucial. Traditional engine research relies on thermodynamic methods and exhaust analysis to examine performance and emission trends present across real-world operating conditions – more recently, optical tools have become increasingly accessible and are providing new methods of understanding combustion phenomena. Interpretation however, is often not directly translatable between optical and thermodynamic engines due to the many mechanical differences between the two. This work aims to provide the foundations for a new “thermo-optical” approach which combines conventional thermodynamic analysis with optical insight into combustion phenomenon to bridge the gap between thermodynamic and optical engine studies.
The development and application of an optical probe performing line of sight pyrometry for in-cylinder soot concentration and temperature measurements, as well as the implementation of a probe for in-cylinder local fuel concentration measurements is detailed. The probes are operated in a 2-litre single-cylinder research engine capable of thermodynamic (“all-metal”) and optical configurations and were utilized under two vastly different operating strategies. These strategies used premixed methane with a diesel pilot (DIDF), and High Pressure Direct Injection (HPDI) for non-premixed NG with a diesel pilot. The pyrometry probe demonstrated the effect of HPDI injection parameters on in-cylinder PM concentration while fuel concentration measurements were used to identify the combustion mode under DIDF conditions, and to provide insight to HPDI injection and combustion characteristics. The probes’ performance and capabilities were evaluated under thermodynamic and optical configurations, with high-speed cameras complementing the probes during optical operation. The framework for interpretation in the “thermo-optical” methodology was developed through analysis of the local fuel concentration, soot concentration and temperature, spatially resolved optical results, and conventional apparent heat release rate (AHRR) analysis.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
26
Christodoulou, Fanos. "Hydrogen, nitrogen and syngas enriched diesel combustion". Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9109.
Pełny tekst źródłaStreszczenie:
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.
27
Rochussen, Jeremy. "Thermodynamic and optical investigation of the combustion mechanisms of diesel-ignited dual-fuel natural gas combustion". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/56260.
Pełny tekst źródłaStreszczenie:
Diesel-ignited dual-fuel (DIDF) combustion of natural gas (NG) is a promising, and immediately available strategy to improve heavy-duty compression-ignition (CI) engine performance to meet challenging and evolving emissions regulations. The DIDF concept utilizes a combination of port-injected NG and direct-injected diesel to couple the relatively low-cost and low-emissions characteristics of NG combustion with the operational and performance characteristics that have made diesel CI engines ubiquitous. This combination of fuelling strategies permits a wide range of different operating modes, which are characterized by a number of fundamental combustion mechanisms. Combustion mechanisms specific to particular modes of DIDF operation have previously been addressed, however a comprehensive conceptual description of the combustion processes and modes of DIDF operation is lacking. A clear context for specific observed phenomena and DIDF operating modes is needed to bridge and extend the conclusions of investigations in this field. That need is addressed by this investigation through experimental analysis of thermodynamic and optical measurements of a broad range of DIDF fuelling modes. A 2-litre single-cylinder CI research engine capable of both conventional and optically-accessible operation was commissioned and operated with port-injected methane (CH₄). Fuelling modes were characterized using the global equivalence ratio (φglobal =0.55—0.88) and pilot fuel ratio (Rpilot =0.06—0.61) and were performed with combinations of pilot injection timing and pressure. A novel set of criteria, which used the measured apparent heat release rate (AHRR), defined sequential stages of DIDF combustion and mapped fundamental regimes of DIDF operation in the Rpilot-φglobal space. Flame propagation, and non-flame propagation DIDF operating regimes were distinguished by an apparent lean flame propagation limit observed at a CH₄ equivalence ratio (φCH₄) equal to 0.4. Pilot injection parameters were observed to be critical to combustion and emissions processes across all operating modes except for a unique subset of operating points with Rpilot=0.06. Spatially-resolved broadband visible light and OH*-chemiluminescence measurements supported the identified operating regimes, and indicated that the conventional conceptual model of DIDF combustion is not a complete description of the DIDF combustion process for all operating modes.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
28
Grochowina, Marcus [Verfasser], Thomas [Akademischer Betreuer] Sattelmayer, Georg [Gutachter] Wachtmeister i Thomas [Gutachter] Sattelmayer. "Dieselpilotzündung in Dual-Fuel-Diesel-Gasmotoren / Marcus Grochowina ; Gutachter: Georg Wachtmeister, Thomas Sattelmayer ; Betreuer: Thomas Sattelmayer". München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/122171936X/34.
Pełny tekst źródła
29
Li, Yu. "A Numerical Investigation of Natural Gas-Diesel Dual Fuel Engine Combustion and Emissions Using CFD Model". Thesis, West Virginia University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10845305.
Pełny tekst źródłaStreszczenie:
Natural gas (NG)-diesel dual fuel engines have been highlighted for their fuel flexibility and high thermal efficiency comparable to diesel engines. However, the addition of NG to compression ignition diesel engines was reported to elongate ignition delay and to increase the emissions of carbon monoxide (CO), unburned methane (CH4), and nitrogen dioxide (NO2). Past research on dual fuel engines has focused on the experimental research on the engine performance, combustion process, and exhaust emissions. The research on detailed mechanism dominating the impact of CH4 on formation of CO and NO2 in cylinder, and the mechanism for CH 4 to survive the combustion process and slip through the cylinder is limited. The examinations of these mechanisms require the simulation of dual fuel engine combustion using a CFD model coupled with chemical kinetic mechanism.
This research numerically investigates the combustion process and exhaust emissions from two NG-diesel dual fuel engines using a CFD model coupled with a reduced primary reference fuel (PRF) chemistry. The CFD model used is Converge-SAGE model with a maximum of 300000 grid points. The fuel chemistry used is a reduced PRF mechanism with 45 species and 142 reactions including a reduced NOx mechanism with 4 species and 12 reactions. The CFD model with reduced PRF chemistry has been validated against experimental data measured in a single-cylinder compression-ignition engine over a wide range of CH4 substitution ratio. A post-processing tool has been developed to calculate, analyze, and visualize the instantaneous rate of production (ROP) of key species in each cell with the known temperature, pressure, and species concentration exported by CFD code. The simulation results are further post-processed to numerically investigate the combustion process and the formation mechanism of CO, and NO2 in a dual fuel engine. The mechanism for CH4 to survive the main combustion process and post-combustion oxidation process is numerically examined.
The research on NO2 formation identified NO+HO2→NO 2+OH as the key reaction dominating the increased formation of NO 2 in dual fuel engines. The HO2 necessary for the formation of NO2 emitted by the engine is produced through the post-oxidation of CH4 that survived the main combustion process. The CO emitted from the NG-diesel dual fuel engine is formed through the oxidation of CH 4 during the late combustion process and post-combustion CH4 oxidation. The CH4 that survived the main combustion and post-combustion oxidation process is mainly distributed in region far from the spray plume of the pilot fuel and its combustion products.
This research also examined approaches capable of significantly reducing the emissions of CH4 from a dual fuel engine. The preliminary results concluded that CH4 emissions can be significantly reduced through optimizing injection timing, and the application of two-pulse fuel injection strategy. Adjusting injector fuel spray angle can also significantly reduce CH4 emissions which should be considered in developing dedicated dual fuel engine.
30
Makkar, Mahesh Kumar. "The effect of quality of gaseous fuels on the performance and combustion of dual-fuel diesel engines". Thesis, University of Surrey, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388983.
Pełny tekst źródła
31
Liu, Benlin. "Experimental and modelling study of reverse flow catalytic converters for natural gas/diesel dual fuel engine pollution control". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0012/NQ59622.pdf.
Pełny tekst źródła
32
Kuyper, Johannes. "Experimental Investigation into the Influence of Piston Crevices on Engine-Out Hydrocarbon Emissions from a Diesel Dual Fuel Engine". Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-184000.
Pełny tekst źródłaStreszczenie:
In today’s society, when the fuel prices are increasing and the climate changes are becoming more and more noticeable, alternative fuels for combustion engines are becoming an important topic for the manufacturers. Two interesting fuels in those perspectives are Biogas and Compressed Natural Gas, CNG. The main constituent of these two fuels is methane. Currently methane is mostly used in spark ignited engines but can also be used in diesel engines since it has a high resistance to knock. An engine concept where methane can be used as fuel in a diesel engine is the Diesel Dual Fuel concept, DDF. In this concept a diesel engine is run with two fuels, diesel and methane, where the methane is injected into the intake runners and the diesel is direct injected into the cylinder. The engine is mainly run on methane and uses a diesel pilot as a liquid spark plug to ignite the homogenous air/methane mixture. The biggest challenge when it comes to emissions for the DDF concept is the HC emissions since the combustion chamber in a diesel engine is not optimized for homogeneous charges, especially noticeable for the piston ring pack crevices. Engine tests are therefore carried out to study the contribution from the piston ring pack crevices to the engine-out HC emissions of a DDF engine. The results show that the flame is not able to burn down into the top land volume and consume the air/fuel mixture there when the standard piston with a top land clearance of 0.6 mm is used. Increasing this clearance to 2.1 mm makes the flame able to burn down into this volume and consume most of the air/fuel mixture there. The contribution to the engine-out HC emissions from the top land volume varies for different lambda values and engine loads. The same trend could be seen for both the light and middle engine loads tested with regards to lambda; however a larger amount of the HC emissions is expected to originate from the top land volume at the higher load. The contribution from the second land volume shows the opposite trend with lambda if compared with the top land volume.I dagens samhälle, då bränslepriserna ökar och klimatförändringarna blir mer och mer märkbara, börjar alternativa bränslen för förbränningsmotorer bli ett viktigt ämne för fordonstillverkarna. Två intressanta bränslen ur dessa perspektiv är Biogas och Komprimerad naturgas. Huvudbeståndsdelen i dessa bränslen är metan. Metan används för närvarande mest i tändstifts motorer men kan också användas i dieselmotorer då det har en stor motståndskraft mot knack. Ett koncept där metan kan användas som bränsle i en dieselmotor är Diesel Dual Fuel, DDF. Det är ett koncept där en dieselmotor körs på två bränslen, diesel och metan, där metan sprutas in i insugskanalerna och dieseln är direktinsprutad in i cylindern. Motorn körs till största delen på metan och använder en liten dieselinsprutning för att antända luft/metan-blandningen. Ur emissions synpunkt är oförbrända kolväten den största utmaningen för DDF konceptet eftersom en dieselmotors förbränningsrum inte är optimerat för en homogen luft/bränsle-blandning, speciellt märkbart för skrymslet mellan kolv och cylindervägg. Motortester har därför utförts för att undersöka hur skrymslena mellan kolv och cylindervägg bidrar till utsläppen av oförbrända kolväten på en DDF motor. Resultatet visar att flamman inte kan brinna ner mellan kolv och cylinderväg och förbruka luft/bränsle blandningen där då standardkolven med ett avstånd mellan kolv och cylindervägg på 0.6 mm används. En ökning av detta avstånd till 2.1 mm gör dock att flamman kan brinna ner och konsumera luft/bränsle blandningen där. Bidraget från skrymslet ovanför översta kolvringen till utsläppen av oförbrända kolväten varierar med både lambda och last. Samma trend med avseende på lambda kunde observeras för både låg- och mellan-lasten som testats men ett större bidrag från detta skrymsle noterades vid den högre lasten. Bidraget från skrymslet mellan de bägge kompressions ringarna till utsläppen av oförbrända kolväten visar på ett omvänt förhållande för lambda jämfört med skrymslet ovanför den översta kolvringen.
33
Nilsson, Vinnars Hans-Christian. "The influence of Swirl and Tumble on the combustion, emissions formation and heat transfer in Diesel Dual Fuel engines". Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141326.
Pełny tekst źródłaStreszczenie:
Det allt större fokus som läggs på kopplingen mellan den ökande konsumtionen av fossila drivmedel och stigande koncentrationsnivåer av växthusgasen koldioxid har föranlett en intensifiering av forskningen inom alternativa drivmedel och förbränningsmotorkoncept, där Diesel Dual Fuel är konceptet som avhandlas under det här examensarbetet. Specifikt undersöks inverkan av rotationsrörelserna Swirl och Tumble på förbränningen, emissionsbildningen och värmeöverföringen i en portinsprutad Diesel Dual Fuelmotor. Resultaten visar att Swirl och Tumble i olika grad påverkar flampropageringen och hur formationen av oförbrända kolväten, härstammandes från ofullständig förbränning, kan kopplas till antingen s.k. crevices eller flamutsläckning beroende på testförhållanden och kolvgeometrier. Resultaten visar också att Swirl och Tumble påverkar efter-oxideringen av de oförbrända kolvätena i olika utsträckning och via olika mekanismer beroende på testförhållanden. För crevice-vinklade tester leder avsaknaden av Swirl-rörelse vid Swirl 1 till att oförbrända kolväten förblir längs med cylinder-linern och undgår fullständig efter-oxidering. För alla tester leder den ökande värmeöverföringen med högre Swirl till en minskad efter-oxidering. Vid maximala Swirl 7, Tumble 2 kompenserar den avancerade, stabilare och mer intensiva förbränningen för den minskade efter-oxideringen givet de lägre avgastemperaturerna. För tester vid magrare förhållanden leder den låga turbulensen vid Swirl 3.8, Tumble 1.25 till en lång tändfördröjning, vilket sammanfaller med instabil förbränning och väldigt höga värden av oförbrända kolväten. Betydligt lägre nivåer av oförbrända kolväten ges vid Swirl 2.5, Tumble 1.2 där en något senare samt stabil förbränning gynnas av låga värmeförluster och kraftig efter-oxidering. Ett liknande resultat ses även vid Swirl 3.8, Tumble 4 där en högre Tumble förkortar tändfördröjningen.With the increasing focus on the link between the increasing consumption of fossil fuel and rising concentration levels of carbon dioxide, research into alternative fuels and engine concepts is intensifying, where Diesel Dual Fuel is the concept investigated during this Thesis. Specifically, the impact of the rotational movements Swirl and Tumble on the combustion, emissions formation and heat transfer in a port injected Diesel Dual Fuel is examined. The results show that Swirl and Tumble to varying degree affect the flame propagation as well as how the emissions formation of unburned hydrocarbons, originating from incomplete combustion, depend upon crevices or flame quenching depending on test conditions. The results also show that the Swirl and Tumble movements influences the after-oxidation of unburned hydrocarbons to different extent and its mechanisms depending on the test conditions. For crevice-geared tests the absence of Swirl movement at Swirl 1 leads to unburned hydrocarbons remaining along the liner during the expansion stroke, thus escaping oxidation. For all tests the increasing heat transfer with higher Swirl leads to reduced after-oxidation. At the maximum Swirl 7 the more advanced, stable and intense combustion compensates for the reduced after-oxidation resulting from the lower exhaust gas temperatures. For leaner test conditions, the low turbulence at Swirl 3.8, Tumble 1.25 results in an extended ignition delay, which coincides with an unstable combustion and very high levels of unburned hydrocarbons. Considerably lower levels of unburned hydrocarbons are seen at Swirl 2.5, Tumble 1.2 where a rather late yet stable combustion benefits from the lower cooling losses and thus improved after-oxidation. Similarly low levels are seen at Swirl 3.8, Tumble 4 where the Tumble shortens the ignition delay duration and the after-oxidation is equally beneficial.
34
SCARCELLI, RICCARDO. "Lean-burn operation for natural gas/air mixtures: the dual-fuel engines". Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/468.
Pełny tekst źródłaStreszczenie:
La ricerca nel campo dei motori a combustione interna è sempre più rivolta ad identificare una soluzione alternativa all’utilizzo dei combustibili derivati dal petrolio, per ragioni di carattere ambientale, politico ed economico. Il gas naturale (NG) è un combustibile ideale per motori a combustione interna, essendo caratterizzato da basso impatto ambientale e consumi ridotti rispetto ai combustibili convenzionali (benzina e gasolio). Inoltre esso è particolarmente adatto ad essere utilizzato in motori ad elevato rapporto di compressione volumetrico, ed è caratterizzato da un ampio campo di infiammabilità. Quest’ultimo aspetto promuove la combustione magra di miscele di aria e NG, ottenendo un ulteriore incremento di rendimento ed un’ulteriore diminuzione dei consumi. I motori dual-fuel NG/diesel permettono di estendere il limite magro d’infiammabilità rispetto ai motori ad accensione comandata alimentati a NG, ed allo stesso tempo consentono di ridurre il trade-off NOX-PM di cui soffrono i motori diesel. Tale tecnologia consiste nell’introduzione del NG come combustibile principale in un motore diesel. Una certa quantità di gasolio viene ancora iniettata, ed agisce come sorgente d’accensione per la miscela di aria e NG. La facilità di conversione rende la tecnologia dual-fuel particolarmente allettante come retrofit di motori diesel già esistenti che in futuro si troverebbero a non soddisfare i sempre più stringenti limiti sulle emissioni inquinanti. Nel presente lavoro, la combustione dual-fuel, con la sua inerente complessità, viene analizzata seguendo un approccio misto numerico-sperimentale. L’attività sperimentale ha come obiettivo l’analisi dei vantaggi e dei problemi connessi con la conversione di un motore diesel heavy-duty al funzionamento dual-fuel, sulla base delle prestazioni e delle emissioni inquinanti. L’attività numerica è caratterizza da un approccio misto 1-D/3-D, ed è stata inizialmente condotta per la corretta comprensione del complesso meccanismo di combustione in modalità dual-fuel. L’analisi multi-dimensionale (3-D) dettagliata del sistema cilindro–pistone è stata successivamente effettuata per la corretta rappresentazione dei fenomeni termo-fluidodinamici evolventi in camera di combustione. Una tale strategia permette la completa descrizione del comportamento dell’intero sistema motore e della combustione dual-fuel nel dettaglio.The research activity on internal combustion engines is increasingly cast to find an alternative solution to reduce the wide utilization of petroleum fuels like diesel oil and gasoline, for environmental, political and economic concerns. Natural gas (NG) is an ideal fuel to be operated in internal combustion engines, since its characteristics allow for much lower environmental impact and reduced fuel consumption with respect the conventional fuels. It also is particularly suitable to be operated under high volumetric compression ratio engines, thus providing higher efficiency, and moreover it is characterized by a wide flammability range. This latter aspect promotes the employment of a lean burn strategy, thus further increasing the engine efficiency and reducing the exhaust emissions. The dual-fuel natural gas/diesel concept allows extending the lean flammability limit of NG with respect to SI-NG operations and simultaneously reducing the NOX-PM trade-off affecting diesel combustion. Such a technology consists in introducing NG as main fuel in a conventional diesel engine. A certain amount of diesel pilot injection is preserved to act as the ignition source for the air/NG mixture. The easiness of dual-fuel conversion makes such technology rather inviting especially as a retrofit for the existing diesel vehicles, which could not meet the more and more stringent emission regulations in the future. In the present study, the dual-fuel combustion process with its inherent complexity is investigated both from an experimental and a numerical point of view. The experimental activity has the main target to analyze the problems connected with the conversion of a heavy-duty diesel engine to dual-fuel operation, and to put into evidence the influence of the main engine parameters on performance and pollutants formation. The numerical activity, characterized by a mixed 1-D/3-D approach, has been carried out with the initial target of a correct understanding of the complex dual-fuel combustion mechanism. A detailed multi-dimensional simulation of the whole working cycle of the engine has been subsequently performed, to provide for the correct representation of the fluid-dynamic effect involved in dual-fuel operations. Such an approach allows for the complete description of the engine overall behavior and the dual-fuel combustion in detail.
35
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.
Pełny tekst źródłaStreszczenie:
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%
36
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.
Pełny tekst źródłaStreszczenie:
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 Çakar. The results will indicate if the suggested concept can be applicable.
37
LEGROTTAGLIE, FRANCESCO. "SISTEMI DI PROPULSIONE E DI GENERAZIONE DELL'ENERGIA AD ELEVATA EFFICIENZA E RISPETTOSI DELL'AMBIENTE". Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1277159.
Pełny tekst źródłaStreszczenie:
Il clima e l’ambiente stanno subendo notevoli cambiamenti verso condizioni estreme a causa del calore non riflesso oltre l’atmosfera terrestre, con conseguenze ambientali oramai evidenti a tutti. Le politica dell’Unione Europea include tra gli obiettivi del futuro piani energetici ed ambientali per contenere queste anomalie nel più breve tempo possibile.
I motori a combustione interna a ciclo Diesel hanno ottima efficienza generale ed affidabilità, ma se alimentati in modo tradizionale con il gasolio emettono inquinanti e gas ad effetto serra. E’ possibile sostituire questo combustibile di origine fossile con biodiesel, o parzialmente mediante la combustione in modalità dual-fuel con miscele gassose per una decisa riduzione dell’impatto sull’atmosfera. L’obiettivo è continuare a sfruttare la robustezza e la flessibilità raggiunta con i motori ad accensione per compressione in vari settori del trasporto pesante o marittimo, piuttosto che per la generazione combinata di energia.
In questa tesi è stata studiata la combustione DF ed RCCI (Reactivity Controlled Compression Ignition) nella quale una parte di gasolio, combustibile di origine fossile e ad alta reattività, viene sostituito da un combustibile a bassa reattività da origine non necessariamente fossile, iniettato in maniera indiretta nel collettore di aspirazione e che forma una carica premiscelata omogenea e magra; una piccola quantità di combustibile ad alta reattività è iniettata direttamente nel cilindro per l’accensione del combustibile.
Le analisi sono state svolte mediante simulazioni CFD 3D del processo di combustione che sono state preliminarmente validate sulla base di dati sperimentali ricavati da un motore Diesel modificato per funzionare in modalità Dual Fuel, testato presso la sala prova motori del Dipartimento.
Sono stati studiati diversi combustibili a bassa reattività tra cui benzina, gas naturale, biogas e miscele di gas naturale e idrogeno. Il gas naturale ed il biogas permettono costi di gestione inferiori ed opportunità sul contenimento delle emissioni allo scarico. Inoltre, il biogas è una fonte di energia rinnovabile e può essere prodotto localmente, aspetti che nell’attuale momento storico hanno una importanza fondamentale.
Sia le prove sperimentali che le simulazioni hanno evidenziato la possibilità di sostituire elevate quantità di gasolio (oltre l’80%) con gas naturale o biogas, mantenendo o aumentando l’efficienza del motore. Solamente ai bassi carichi, l’elevato rapporto aria combustibile della carica premiscelata rende critica la combustione Dual Fuel. E’ stata quindi investigata la possibilità di miscelare idrogeno al gas naturale (fino al 50% in volume) al fine di migliorare la qualità della combustione. Questo ha permesso di migliorare la combustione ai bassi carichi, estendendone la zona di funzionamento in modalità Dual Fuel e di riducendo le emissioni ai carichi medio/alti.
Sul biogas è stato fatto, inoltre, un approfondimento specifico per un’applicazione cogenerativa. Il biogas di origine vegetale, ed autoprodotto in loco mediante fermentazione anaerobica, è stato simulato in combustione DF in diverse quote parti di anidride carbonica, fino ad un 50%, ossia frazioni corrispondenti a reali composizioni di questo gas. Per questa variabilità non sono garantite sempre le medesime prestazioni ed occorrono opportune calibrazioni di anticipo di iniezione. E’ stato studiando il caso reale di soddisfacimento del fabbisogno energetico di un’azienda agricola, mediante autoproduzione di energia combinata elettrica e termica da motore endotermico a ciclo diesel in modalità DF. Per questa applicazione sono stati considerati aspetti prestazionali, di emissioni allo scarico, oltre che aspetti economici di fattibilità e rientro dell’investimento.Climate and environment are undergoing significant changes to extreme conditions due to the heat not reflected beyond the Earth’s atmosphere, with environmental consequences now obvious to everyone. European Union policies include energy and environmental plans to contain these anomalies as soon as possible. Diesel internal combustion engines have excellent general efficiency and reliability, but if they are powered in a traditional way with diesel oil they emit pollutants and greenhouse gases. It’s possible to replace this fossil fuel with biodiesel, or partially by burning it in dual-fuel mode with gaseous mixtures to significantly reduce pollutant emissions. The aim is to continue to exploit the robustness and flexibility achieved with compression ignition engines in various sectors of heavy transport or maritime sector, rather than for combined energy generation. In this thesis combustion DF (dual fuel) and RCCI (Reactivity Controlled Compression Ignition) have been investigated in which a part of diesel oil, fuel of fossil origin and high reactivity, is replaced by a fuel with low reactivity from origin not necessarily fossil (for example: biogas, hydrogen ), indirectly injected into the intake manifold and forming a homogeneous and lean premixed charge; a small amount of high reactivity fuel is injected directly into cylinder ignite the charge. The analyses were carried out using 3D CFD simulations of the combustion process which were validated preliminarily on the basis of experimental data obtained from a modified Diesel engine operating In dual fuel mode. The experimental campaign has been carried out at the test bed of Unimore Departement. Various low reactivity fuels including gasoline, natural gas, biogas and mixtures of natural gas and hydrogen have been investigated. Natural gas and biogas ensure lower operating costs and can leads to reduce exhaust emissions. Furthermore, biogas is a renewable source of energy and can be produced locally, aspects that are of fundamental importance in this historical moment. Both experimental tests and simulations have shown the possibility of replacing high quantities of diesel oil (over 80%) with natural gas or biogas, maintaining or increasing the engine efficiency. Only at low load conditions, the high fuel air ratio of the premixed charge makes dual fuel combustion critical. The possibility of mixing hydrogen with natural gas (up to 50% by volume) was then investigated in order to improve the quality of combustion. This has allowed to improve combustion at low loads, extending the operating zone in dual fuel mode and reducing emissions at medium/high loads. On biogas, moreover, a specific deepening has been done for a cogenerative application. The biogas of plant origin, and self-produced on site by anaerobic fermentation, has been simulated in dual fuel combustion in different parts of carbon dioxide, up to a 50%, fractions corresponding to real compositions of this gas. For this variability, the same performances are not always guaranteed and appropriate injection timing tunings are required. The real case of meeting the energy needs of an agricultural holding has been studied, by means of self-handling of combined electric and thermal energy from diesel cycle endothermic engine in dual fuel mode. For this application were considered performance aspects, exhaust emissions, as well as economic aspects of feasibility and return of the investment.
38
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.
Pełny tekst źródłaStreszczenie:
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.
39
ASTORSDOTTER, JENNIFER, JONAS RICKNELL, FIONA YU i Axel Forsgren. "Utformning av avgaskatalysator". Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173552.
Pełny tekst źródłaStreszczenie:
Naturgas är ett alternativ till oljebaserade bränslen. Ur ett miljöperspektiv är naturgasen fördelaktig eftersom den vid förbränning ger mindre utsläpp av miljöfarliga ämnen än olja. I en diesel dual-fuel motor används diesel och naturgas som bränsle. Naturgas består till största delen av metan. För att oskadliggöra den del av metangasen som inte förbränns i motorn krävs en avgaskatalysator som kan bryta ned det relativt stabila metanet vid låga temperaturer. Målet med det här kandidatexamensarbetet är att tillverka och testa tre olika avgaskatalysatorer för nedbrytning av metan. De tre katalysatorer som valdes för tillverkning och testning var Pd/Al2O3, Pd/SnO2 och In2O3/SnO2 (ITO). Valen baserade sig på att katalysatorerna som tillverkades skulle vara aktiva för nedbrytning av metan vid låga temperaturer. ITO sågs som en extra intressant kandidat eftersom In är billigare än ädelmetallen Pd. Pd/Al2O3 tillverkades med en kommersiell support och impregnering av Pd genom ”incipient wetness” (IW). Pd/SnO2 tillverkades på samma sätt. ITO tillverkades genom ”forward co-precipitation”. En monolit testades för varje katalysator. Vid ungefär 315 °C kunde 10 % omsättning av metan detekteras för alla tre katalysatorer. Pd/Al2O3 var den katalysator vars aktivitet förbättrades som mest då temperaturen ökade ytterligare. Katalysatorerna testades bara en gång. För att statistiskt säkerställa resultaten behöver upprepade tester göras. Resultaten överensstämmer delvis med tidigare studier. Slutsatsen av arbetet är att alla tre katalysatorer fungerar och att ITO skulle kunna vara en billigare men i övrigt likvärdig avgaskatalysator för en diesel dual-fuel lean burn motor vid 315 °C. Fler tester måste dock göras för att ta reda på om ITO verkligen är ett mer fördelaktigt alternativ.
40
SAVIOLI, TOMMASO. "Analisi numerica e sperimentale di processi di combustione non convenzionali nei motori a combustione interna". Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1277158.
Pełny tekst źródłaStreszczenie:
Oggigiorno le emissioni inquinanti rappresentano il vincolo più importante nello sviluppo dei motori a combustione interna. Il riscaldamento globale in continuo aumento è causato principalmente dalle emissioni di gas serra, principalmente dalla C02. I motori a combustione interna devono necessariamente aumentare l’efficienza e, allo stesso tempo, migliorare le emissioni inquinanti per poter ottemperare ai limiti imposti dalle leggi.
L’alta efficienza, l’affidabilità, e la flessibilità richiesta nei moderni veicoli per trasporto persone specialmente nei motori diesel rende tali propulsori adottabili su utilizzi quasi stazionari ( e.g. aeromotive, autotrasporto, generatori di energia elettrica) mediante l’utilizzo di combustibili alternativi miscelati con Diesel. Il costo di tali propulsori che è ovviamente più alto degli odierni motori industriali utilizzati per la produzione di energia non determina un grande ostacolo, in quanto la re-ingegnerizzazione di tali propulsori per implementare il funzionamento dual fuel sarebbe limitata, ma permetterebbe di aumentare efficienza e prestazioni.
L’obiettivo di questo lavoro di tesi è quello di esplorare il potenziale di un moderno motore diesel alimentato con differenti miscele di combustibili alternativi (Metano e Benzina) pre-miscelati nella aspirazione . Questo processo di combustione viene chiamato RCCI ( Reactive Controlled Compression Ignition) e permette incrementare il rendimento globale e ridurre le emissioni inquinanti.In particolare le emissioni di CO2 possono diminuire con l’utilizzo di questa tecnologia. In questo contesto è stato preso in considerazione un motore due tempi per aerotrazione; questa tipologia di propulsore non ha limitazioni nella realizzazione della geometria della camera di combustione, a differenza dei quattro tempi, inoltre le minori pressioni in fase di combustione rendono questi motori maggiormente adattabili alla combustione RCCI.
Il presente lavoro è concentrato sulla validazione numerico sperimentale supportando i calcoli CFD di combustione mediante l’utilizzo di una sala prova utilizzando un moderno motore diesel installato sul banco prova dell’Univestità di Modena ed equipaggiato con un sistema si analisi della pressione in camera di combustione; i calcoli CFD sono stati effettuati utilizzando una versione modificata di Kiva 3v. Il motore due tempi è stato studiato con una campagna di calcoli CFD per studiare il potenziale della combustione RCCI applicata a questi propulsori.
Questi differenti processi di combustione possono avere significativi vantaggi in termini di efficienza globale del motore e di emissioni inquinanti, questi risultati pero possono essere raggiunti solamente con un attento processo di calibrazione motore e di una importante campagna sperimentale di calcoli.Nowadays pollutant emission represent the main topic in internal combustion engines development. Global warming is increased due to the high emissions of greenhouse gases, in particular Co2 emissions. Internal combustion engines must increase global efficiency and, at the same time, decrease pollutant emissions in order to be compliant to future legislation constraints. The high efficiency, reliability and flexibility of modern passenger car Diesel engines makes these power units quite attractive for steady many quasi-steady application ( e.g. aeromotive, truck ,heavy duty, generators) totally or partially running on fuels blends or different combustion process. The engine cost, which is obviously higher than that of current industrial engines, may not be a big obstacle, provided that the re-engineering work in order to implement dual fuel operation is limited and that performance and efficiency are enhanced. The goal of this work is to explore the potential of a current state of the art turbocharged Diesel engine running on both Diesel Fuel and dual fuel combustion with the use of a premixed charge of Methane or Gasoline. This particular combustion process called RCCI ( Reactive Controlled Compression Ignition) can improve engine global efficiency and reduce pollutant emissions. In particular CO2 emissions decreases because of the different nature of the fuel. In this contest an analysis is made also in a two stroke engine for aircraft application. This kind of engine can be quite attractive for the less constraints in combustion chamber design, instead of four stroke; furthermore low combustion pressures lead to fit better RCCI concepts. The present thesis is focused in experimental and numerical validation supporting CFD combustion calculation with experimental analysis in a modern Diesel Engine by using a test bed equipped with an indicating system for experimental campaign and a custom version of CFD 3D software Kiva 3V. Two stroke engine has been study by several cfd calculation campaign in order to investigate two stroke potential in RCCI application. These different combustion process can have several advantages in terms of global efficiency and pollutant emission, but these results can be achieved only with an accurate combustion process calibration and several CFD combustion calculation.
41
Muca, Sonia. "Implementazione di un modello di controllo per la definizione dei target di iniezione di combustioni innovative". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Znajdź pełny tekst źródłaStreszczenie:
Con il presente lavoro di tesi è stato sviluppato e implementato un modello di controllo in Simulink per la definizione dei target di iniezione e la transizione di un motore ad accensione spontanea in condizioni di alimentazione Dual Fuel.
Il modello è costituito da due sottosistemi con finalità diverse: uno deputato al passaggio in Dual Fuel (diesel/benzina) e l’altro per tornare alla condizione di sicurezza di alimentazione diesel.
Una volta verificato il corretto funzionamento nelle prove numeriche, è stato sperimentato sul motore presente in banco prove e i test sperimentali sul modello sono stati esposti nel presente lavoro.
Questo modello rappresenta uno spunto per potenziali sviluppi sul controllo di combustioni innovative.
42
Alkadee, Dareen. "Techniques de réduction et de traitement des émissions polluantes dans une machine thermique". Phd thesis, Conservatoire national des arts et metiers - CNAM, 2011. http://tel.archives-ouvertes.fr/tel-01005123.
Pełny tekst źródłaStreszczenie:
Cette thèse de doctorat, a consisté, dans une première partie, à introduire d'une part, la notion de l'analyse du cycle de vie " ACV " et celle des biocarburants. D'autre part, à présenter l'intérêt d'appliquer une ACV sur des biocarburants afin de valoriser leurs bilans énergétiques et analyser leurs impacts environnementaux face aux carburants conventionnels. Dans une deuxième partie, nous avons comparé, d'un point de vue énergétique et environnemental, 3 scénarios de production d'électricité : 2 scénarios de cogénération (turbine à vapeur et ORC) pour la production d'énergie électrique et thermique à partir de biomasse, et un scénario de cogénération par moteur diesel. Ces scénarios sont comparés à l'aide de deux méthodes orientées " analyse des dommages ": Eco-indicateur 99 (E) et IMPACT2002+Dans une troisième partie, on a abordé la valorisation du biogaz sous forme de carburant dans des moteurs "dual fuel" pour des engins agricoles dans le but de déterminer l'impact environnemental lié à l'utilisation de ce carburant alternatif au diesel par rapport aux autres biocarburants. Les méthodes Eco-indicateur 99 (E) et CML ont été utilisées ici. On a pu ainsi identifier les principaux polluants générés à chaque étape du cycle de vie de l'agrocarburant et les étapes qui ont les plus grands impacts environnementaux et on a identifié, selon nos critères et par rapport au contexte, le scénario énergétique le plus compatible avec le principe de développement durable.
43
KUMAR, PANKAJ. "PERFORMANCE AND EMISSIONS ANALYSIS OF CNG–DIESEL DUAL FUEL ON A VCR ENGINE". Thesis, 2015. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14370.
Pełny tekst źródłaStreszczenie:
ABSTRACT
The rapidly depletion of petroleum reserves or resources have promoted research for
alternative fuels for internal combustion engines. The C.I. Engine is a very important
prime mover being used in the buses, trucks, locomotives, tractors, pumping sets and
many other applications, small and medium electric power generation and marine
propulsion etc. The running costs of C.I. Engines are much less than S.I. Engines and
hence make them attractive for industrial, transport and other applications.
A dual fuel diesel engine is a diesel engine fitted with a fuel conversion kit to enable use
of clean burning alternative fuel like compressed natural gas. Dual fuel engines have
number of potential advantages like fuel flexibility, lower emissions, higher compression
ratio, better efficiency and easy conversion of existing diesel engines without major
hardware modifications. In view of energy depletion and environmental pollution, dual
fuel technology has caught attention of researchers. It is ecological and efficient
The objective of the present major project work is to investigate the possibility of dual
fuelling of Compression Ignition (C.I.) engine with Diesel and Biodiesel with
Compressed Natural Gas (CNG) in order to reduce engine emissions and enhance its
thermal efficiency. A Direct Ignition, single cylinder 4 stroke 3.5kW Variable
Compression Ratio Diesel Engine was operated in dual fuel mode. The engine was
initially started with Diesel injection and subsequently CNG was supplied with the
incoming air. After self-ignition of diesel and blend of biodiesel fuel, CNG-Air mixture
ignited
The investigation on three different compressions ratio show the use of CNG resulted in
significant reduction of smoke opacity and Nitrogen oxide (NOX) emissions with a slight
penalty on CO and HC exhaust Emissions.
Performance and Emissions Analysis of CNG-Diesel Dual Fuel on A VCR Engine
Mechanical Engineering Deptt. , Delhi College of Engineering, Delhi Page 5
Our study also throws light on present limitations and drawbacks of dual fuel-engines and
proposed methods to overcome these drawbacks. Analysis of recent research activities
carried out to study effect of different parameters affecting performance of diesel - CNG
and Biodiesel - CNG dual fuel engines is also summarized here. Future scope of research
for these engines is also discussed.
44
KUMAR, PARVESH. "EXPERIMENTAL INVESTIGATIONS ON PERFORMANCE OF DUAL FUEL DIESEL ENGINE USING CNG AND BIODIESEL". Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16045.
Pełny tekst źródłaStreszczenie:
The power generation and transportation sectors are heavily dependent on fossil fuels, whose
combustion results in high level of air pollution. However, uncertainties about the long-term
availability coupled with price perturbation of fossil fuels are a key challenge due to which
alternative fuels are getting more attention. Gaseous fuels such as Compressed Natural Gas
(CNG) or hydrogen are very promising for use in Spark Ignition (SI) or Compression Ignition
(CI) Engines. The research on the use of gaseous fuels in CI engines is still underway unlike SI
engines, where it has even been commercialized. The utilization CNG with environmental
friendly liquid biofuels is one of the most promising combustion techniques in dual fuel CI
engine without a reduction in power. Also, application of exhaust gas recirculation (EGR) will
improve the performance of dual fuel engine.
The objective of the present research work is to evaluate dual fuel combustion technique
using a different combination of fuels. The effect of the use of CNG as primary fuel and, diesel,
Jatropha oil methyl ester (JOME), Orange peel oil methyl ester (OPOME) and their blends as
pilot fuel in CI engine, on combustion, performance and emissions characteristics of the engine
was studied and compared with baseline data of diesel engine operation.
A Kirloskar diesel engine (Model-CAF 8) was modified in such a way that it can operate
in both conventional diesel mode as well as dual fuel mode. The engine was run at the rated
speed of 1500 rpm for six loading conditions (i.e. no load, 20%, 40%, 60%, 80% and full load)
for both the modes. During dual fuel combustion mode, the mass flow rate of pilot fuel was kept
constant and mass flow rate of CNG varied with the load. The engine was connected to a
Experimental Investigations on Performance of Dual Fuel Diesel Engine using CNG and Biodiesel P a g e | viii
computer to analyze the in-cylinder pressure data which would further help to calculate the mass
burn fraction, heat release rate, and cumulative heat release. A combustion chamber was also
developed to measure the ignition delay of liquid fuels. An exhaust gas recirculation (EGR) set
up was also developed for the present work.
Response surface methodology (RSM) was used as an optimization tool for biodiesel
production. The evaluation of physicochemical properties (such as density, kinematic viscosity,
cetane number, flash point etc.) of all pilot fuels was carried and found suitable for use. The
auto-ignition temperature of all pilot fuels was also evaluated. The engine trial was conducted by
taking different fuel combinations (i.e. CNG+diesel, CNG+JOME, CNG+J50D50,
CNG+OPOME, CNG+OP50D50) with and without application of EGR and the combustion,
performance and emissions characteristics of dual fuel engine were studied.
It was found that JOME, OPOME and their blends show better results compared to diesel
as pilot fuel in dual fuel engine especially up to higher load. The use of biodiesel shows better
BTE and lower CO emissions than diesel as pilot fuel. However, at full load, diesel as pilot fuel
has highest BTE compared to all another mode of operations. The highest BTE of the
conventional diesel engine was found 28.58%, where the highest BTE for dual fuel mode was
found 30.65%, 30.35%, 30.51%, 30.44% and 30.58% for diesel, JOME, J50D50, OPOME and
OP50D50 as pilot fuel respectively. It was clearly observed that the blending of biodiesel in
diesel improves the BTE of the engine. The utilization of EGR was found to improve the
emissions characteristics of dual fuel engine. At low load and with EGR, NOX emissions reduced
by 18.4%. The application of EGR also reduced the CO and UHC emissions by 3.2% and 6.3%
respectively. Also, at low load, the application of EGR increases the BTE of the engine by 3%.
Experimental Investigations on Performance of Dual Fuel Diesel Engine using CNG and Biodiesel P a g e | ix
It is concluded that dual fuel engines are capable of reducing exhaust emissions without
reducing the power and CO and unburned HC can be reduced with the application of EGR in
dual fuel engine. Further investigations on advancing injection timing of pilot fuel are
recommended in order to meet with emission regulations.
45
Hsien-Cheng, Chen, i 陳憲政. "Benefit Evaluation of the Taiwanese City Bus Converted into Diesel/CNG Dual-Fuel System". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/52435282694560305773.
Pełny tekst źródłaStreszczenie:
碩士大葉大學
機械工程研究所碩士在職專班
96
In order to improve the air quality in the metro area and decrease the dependence on traditional fossil fuels、advanced countries have to legislate the components of car fuels control the standards of automobile exhaust gas and encourage to use a variety of low polluting car substitution fuels. Among these fuels、natural gas is chosen to be the primary substitution fuel due to its high yield、low costs、and low pollution after combustion、high-energy efficiency and safety. This study choose the most used environmental second-stage standard engine HINO EM100-G in the public transport industry of Taiwan region as the object for exploring modifications. Collaborating with KUOZUI diesel bus undercarriage of LRK1MRA model and by modifying in used diesel engine buses into diesel/natural gas dual-fuel system to test and evaluate gas emissions、noise variation、vehicle performance and so on before and after the modification、and further discuss the modification costs and economic effective of CNG dual-fuel System. The results of this study have proved by using natural gas as the fuels for the vehicles、it has immediate effects on decreasing car emissions and decreasing the dependence on the fossil fuel from the society. In overall speaking、buses using CNG dual-fuel System have reduced 22.1% in CO2 emissions、15.5% in NOX emissions and even 43.7% in PM. Under the simulated condition of metro on-road test、its average energy substitution rate of diesel fuel was 62%. A diesel vehicle modifies to a CNG compound combustion system car in has advantages of easy to modify、low modification costs、longer travel distance and suitable in areas where gas stations are not common and so on. However、at the same time it also has the disadvantages of limited improvement in the gas emissions (compared to pure natural gas vehicles)、low efficiency in low loading engines、increased maintenance costs、cut down of loading capacity due to having two combustion systems at the same time and reduced acceleration. The results of this study can be provided as references and applications to the governments and related bus industry to promote natural gas vehicles.
46
De, Robbio Roberta. "CFD study of diesel engine operating in dual fuel mode". Tesi di dottorato, 2020. http://www.fedoa.unina.it/13170/1/PhD_Tesi_Roberta_DeRobbio.pdf.
Pełny tekst źródłaStreszczenie:
In the last years climate change has become an emergency that united countries of the world to make agreements to reduce pollutant emissions. In this context, the diesel engine, whose combustion is characterised by high emissions of particulate matter and nitric oxides, is likely to disappear from the future automotive market. However, the high performances of this well established engine may still represent a resource in terms of power, efficiency and reliability. In this regard, a possible solution is to readapt the engine to operate in Dual Fuel mode. In order to assess the benefits and limits of this technology, it is necessary a deep investigation of the phenomena that characterise the combustion development that results further complicated, due to the interaction of two burning fuels.
To this purpose, Computational Fluid Dynamics is the most powerful tool allowing investigation of the different processes that take place inside the cylinder such as turbulence, fuel atomisation and chemical kinetics. Clearly, major difficulties are encountered in the choice of a combustion model suitable for both fuels. In this regard, kinetics plays a key role in the description of the oxidation process.
This thesis aimed at a progressive improvement of the methodology and more detailed kinetic mechanism were utilised to better comprehend the actual combustion mechanism and pollutants formation. Starting from a simplified kinetics scheme for diesel oil and natural gas oxidation, firstly a new mechanism including 9 reactions was introduced for the ignition of methane (considered as the main component of natural gas), in this way it was possible to release from empirical correlations for the ignition of at least one of the two fuels. Finally, this model was compared with a more detailed scheme consisting of 100 species and 432 reactions.
Further criticalities arise from the wide operating range of the engine, especially for automotive applications. To overcome the typical problem related to the computational cost of the CFD based approach, the utilisation of different tools such as a one-dimensional model demonstrated to be helpful for extending the numerical investigations to multiple cases characterised by either different load levels or changes in the fuel injection settings.
In this framework the experimental activity represented an effective tool for the validation of the numerical outcomes, since experimental data provided important information on the behaviour of three distinct diesel engines, say: a light-duty common rail engine, an optically accessible research engine and a heavy-duty engine. The main point to be highlighted is that the study of three engines with different characteristics allowed a wide investigation on different operating conditions.
47
Figueiral, Carlos Miguel Almeida. "Aplicação do conceito de combustão dual-fuel num motor diesel pesado". Master's thesis, 2016. http://hdl.handle.net/10316/36969.
Pełny tekst źródłaStreszczenie:
Durante as últimas décadas, a combustão Dual-Fuel, com recurso a combustíveis gasosos alternativos, tem sido alvo de uma forte investigação, na medida que constitui uma boa abordagem para a diversificação das fontes energéticas e para a redução das emissões de poluentes.
O objetivo deste estudo consiste no estudo teórico, técnico e prático de um veículo pesado (MAN TGA 18.433 FLS 36LX) equipado com um motor Euro 3 D2066 LF01 convertido para Dual-Fuel a GPL. A configuração inovadora do sistema proposto permite a variação do fornecimento do combustível original (gasóleo) através do controlo da pressão do rail e da pressão de sobrealimentação lidas pelo controlador original do motor. Esta configuração possibilita a aplicação de um sistema Dual-Fuel a um veículo com caixa de velocidades automática sem que as suas características de funcionamento sejam comprometidas, o que não se verifica para os sistemas originais existentes até então no mercado.
O combustível de adição usado para alimentar o sistema instalado durante o estudo foi o GPL, devido essencialmente a fatores como a relativa facilidade de armazenamento deste combustível, o número elevado de postos de abastecimento a nível nacional/internacional e ainda a necessidade de otimização dos sistemas que fazem uso desta fonte de energia.
Foi desenvolvida uma metodologia de cálculo com recurso ao software Microsoft EXCEL que permite simular os consumos e as poupanças associadas à utilização deste tipo de sistemas.
Foram feitos testes experimentais em estrada e em banco de potência de forma a calibrar e avaliar todo o sistema. Posteriormente com os dados obtidos foi feita uma análise do desempenho do veículo e dos consumos e poupanças decorrentes do seu funcionamento em Dual-Fuel a GPL.During the last decades, the Dual-Fuel combustion, based on alternative gaseous fuels, has been the target of a deep research, and is a good approach to reducing global dependence for fossil fuels and the reduction of pollutant emissions. The goal of this study consists on a theoretical, technics and practical study of a heavy-duty vehicle (MAN TGA 18.433 FLS 36LX) equipped with a Euro 3 engine D2066 LF01 running on LPG Dual-Fuel operation. The innovative configuration of the proposed system, allows cutting the original diesel fuel by controlling the rail pressure and boost pressure read by the original ECU. This configuration enables the application of a Dual-Fuel system to a vehicle with an automatic gearbox without its performance being compromised, which is not the case for existing original systems on the market. The fuel used to power the system installed during the study was LPG, mainly due to factors such as the relative facility of his storage, the high number of national / international fuelling stations and the need for optimization of the systems that use this energy source. A methodology using the Microsoft EXCEL software was developed to simulate consumptions and savings associated with the use of the Dual-Fuel systems. In order to evaluate and calibrate the entire system, experimental tests have been made on the road and in a dyno. Then with the data obtained was made an analysis of the vehicle performance, consumption and the savings obtained with the LPG Dual-Fuel operation.
48
HUANG, SHIN-SHIANG, i 黃新翔. "Experimental Investigation on Performance and Emission Characteristics of Dual Fuel Common-rail Diesel Vehicle with Hydrogen Fuel". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/wf7hpz.
Pełny tekst źródłaStreszczenie:
碩士國立高雄第一科技大學
機械與自動化工程系碩士專班
105
In recent years, the energy crisis and environmental pollution issues by the world's attention, all actively involved in research and development of alternative energy sources and reduce environmental pollution emissions. Taiwan's diesel passenger car market is open, so that only large commercial vehicles will emit carbon particulate emissions, become a small passenger cars have emissions and an increasing trend. This study uses a common-rail diesel passenger car, adding hydrogen dual-fuel combustion to observe the impact of vehicle emissions and energy saving fuel consumption. According to test results, show that the addition of hydrogen after the exhaust gas NOx increased significantly, while in other exhaust gas and fuel consumption were significantly decreased.
49
Poonia, M. P. "Investigations on combustion and performance optimization of a dual fuel engine using LPG and diesel". Thesis, 1996. http://localhost:8080/iit/handle/2074/5045.
Pełny tekst źródła
50
Govil, Gyan P. "Investigations on a dual fuel engine using diesel and biogas for performance optimization and conversion kits". Thesis, 1999. http://localhost:8080/iit/handle/2074/5088.
Pełny tekst źródła