Dissertations / Theses on the topic 'Compression Ignition'
To see the other types of publications on this topic, follow the link: Compression Ignition.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Compression Ignition.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
SANCHEZ, FERNANDO ZEGARRA. "COMPRESSION IGNITION OF ETHANOL-POWERED IN RAPID COMPRESSION MACHINE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29324@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Com o passar do tempo, a humanidade tem uma maior dependência na geração de energia, utilizada para promoção de conforto, transporte e outros. Com a finalidade de resolver este aumento de demanda, novas fontes eficientes, de preferência renováveis, estão sendo pesquisadas. O transporte é uma das atividades que tem maior dependência dos combustíveis fósseis, além de ser também um dos maiores geradores de gases de efeito estufa. É por isso, que em diversas partes do mundo, o homem pesquisa novas fontes de energia renováveis que possam ser substitutas dos atuais tradicionais usados no transporte. Sabe-se, que os motores Diesel são mais eficientes com relação aos motores Otto. Devido a este fato, há mais 30 anos pesquisam-se e desenvolvem-se sistemas de ignição por compressão, movidos com combustíveis renováveis, o qual permita a diminuição da dependência dos combustíveis fósseis e garanta a redução de gases de efeito estufa. O etanol é um candidato para substituir o oleo Diesel, mas tem que se levar em conta algumas alterações (aumento da relação de compressão, adição de melhoradores da autoignição, etc.) antes de ser utilizado nos motores Diesel. Com base nisto, a presente tese apresenta uma nova proposta, utilizar como melhorador da autoignição do etanol o n-butanol. Para tal propósito se desenvolveu diversos testes com diversas relações de compressão, percentuais em massa de aditivo na mistura de etanol e diversos avanços da injeção. Os testes foram realizados em uma máquina de compressão rápida (MCR) com misturas de etanol e polietilenoglicol 400 e 600, n-butanol, além dos testes refenciais com óleo Disel e ED95. Os resultados mostram que o n-butanol, com uma participação de 10 por cento na mistura, pode ser utilizado como melhorador da autoignição do etanol em sistemas de ignição por compressão.
Over time, humanity has developed a greater reliance inpower generation, used to promoter comfort, transport and others. In order to address this increased demand new efficient sources are being searched, in preference, renewable sources. Transportation is one of the activities that have greater reliance on fossil fuels as well as being one of the largest generators of greenhouse gases. Therefore, in many parts of the world men are engaged in the search of new renewable energy sources that can substitute the current one used in transport. It is known that diesel engines are more efficient in comparison to the Otto engime. Due to this fact, for more than 30 years research has been conducted in order to develop ignition systems by compression, powered with renewable fuels, which reduces the dependence on fossil fuels and the emission of greenhouse gases. Ethanol is a viable candidate to replace diesel oil, but some improvements have to be accounted for before it s used in diesel engines, improvements such as the increase in compression ratio, adding auto-ignition improves, etc. Based on the facts presented, this thesis offers a new proposal, the use of n-butanol as an auto-ignition improver for ethanol. For this purpose several tests have been executed with various compression ratios, mass percentage of additive in the mixture off ethanol and many start of injections. The tests were performed in a rapid compression machine (RCM) with mixtures of ethanol and polyethylene glycol 400 and 600, and n-butanol inaddition to the reference test with diesel oil and ED95. The results show that n-butanol with a 10 per cent share of the mixture, can be used as an auto ignition improver for ethanol in compression ignition systems.
2
Hahn, Tairin. "Ignition study in rapid compression machine." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46641.
Full textAbstract:
Thesis (Mech. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (leaves 79-81).
As it becomes more and more difficult to find "easy" oil, various alternative fuels are introduced to the markets. These fuels have chemical properties that are different from the traditional gasoline and diesel fuels so that engine efficiency and other engine behaviors may be affected To improve engine efficiency and to identify which alternative fuel is the cleanest fuel solution, it is necessary to compile information about the ignition delay, which governs auto-ignition in spark-ignition (SI), compression-ignition (CI) and homogeneous charge compression-ignition (HCCI) engines. In this study, we measured ignition delay on the Rapid Compression Machine (RCM). RCM is a single-stroke device, which compresses uniform mixtures to engine-like condition. We can interpret from the pressure the detailed heat release process. A comprehensive ignition delay database of toluene/n-heptane mixtures and gasoline/ethanol mixtures was established The data allow us to calculate the auto-ignition behavior in engines. Depending on application the correct choice of alternative fuels may be made.
by Tairin Hahn.
Mech.E.
3
Roberts, Philip John. "Fuel and residual effects in spark ignition and homogeneous charge compression ignition engines." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530821.
Full text
4
Zeraati, Rezaei Soheil. "Experimental investigation of a premixed compression ignition engine." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7037/.
Full textAbstract:
Premixed compression-ignition (PCI) combustion techniques using low-cetane fuels, including Dieseline (mixture of diesel-gasoline) and naphtha, were investigated in a light-duty multi-cylinder CI-engine focusing mainly on reducing emissions while maintaining or improving the brake-thermal-efficiency. Different fuel-injection and intake/exhaust handling strategies were investigated in a wide engine operating load range from 1.4 to 17.3 bar BMEP. Moreover, an out-cylinder emission reduction technique through using a diesel-oxidation-catalyst (DOC) was investigated. Hot (uncooled) exhaust-gas-recirculation (EGR) combined with low fuel-injection-pressure (as low as 150 bar) significantly enhanced combustion-performance (COV < 5%) and reduced carbon-monoxide and hydrocarbon emissions at lower loads, when using low-cetane fuelled PCI techniques. At 1.4 to 6 bar BMEP, particulate emissions were reduced by >99% with respect to the diesel-CI baseline, in terms of number and mass, while maintaining brake-specific-NOx below 0.4 g/kWh. At loads more than 6 bar BMEP, double-injection strategy advanced combustion-phasing, where the first injection-event was shown to be significantly influential. Due to narrower boiling-range of naphtha compared to Dieseline, naphtha PCI resulted in high-COV at low loads, while it resulted in rapid-combustion at medium/high loads. Utilisation of the hot-EGR is a “win-win” strategy to enhance the combustion-process of the PCI-engine and reduction of the volatile/semi-volatile compounds using the DOC.
5
LOAIZA, JUAN CARLOS VALDEZ. "REACTIVITY CONTROLLED COMPRESSION IGNITION OF DIESEL FUEL AND ETHANOL IN RAPID COMPRESSION MACHINE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35559@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Serão necessários muitos anos para que os biocombustíveis sejam capazes de substituir integralmente os derivados fósseis. Este trabalho visa estudar formas alternativas de conversão de energia contida nos combustíveis utilizados em motores de combustão interna. Maiores eficiências na conversão da energia contida no combustível e uma menor emissão dos gases de exaustão são benefícios associados à ignição por compressão de reatividade controlada, RCCI, onde dois fluidos com diferentes reatividades são introduzidos na câmara de combustão em instantes diferentes. Optou-se pelo uso de uma máquina de compressão rápida, MCR, capaz de controlar parâmetros relevantes, como taxa de compressão, pressões, tempos de injeção, que foi adaptada para receber dois sistemas de injeção direta na câmara de combustão. Como segundo combustível, que substitui parcialmente o óleo diesel, que é empregado tradicionalmente em motores de ignição por compressão, optou-se pelo etanol hidratado. Os estudos revelaram que diferentes formas de injeção dos dois combustíveis produzem processos muito diferentes, para as mesmas quantidades de combustíveis injetados. Os resultados são apresentados na forma de pressão indicada como função do ângulo equivalente, bem como calor liberado e atraso de ignição. Experiências foram conduzidas para uma ou duas injeções de etanol por ciclo, em diferentes tempos. Altas razões de substituição do combustível fóssil foram obtidas, quando comparadas com a técnica de fumigação, onde o segundo combustível é misturado externamente ao ar de combustão.
Many years will be needed for biofuels or other renewable sources to be able to fully replace fossil fuels. This work aims to study alternative ways of converting energy contained in fuels used in internal combustion engines. Higher efficiencies in converting the energy contained in the fuel and lower emission of harmful exhaust gases are benefits associated with the Reactivity Controlled Compression Ignition, known for RCCI. In this type of combustion, two fluids with different ignition-reactivity characteristics are introduced into the combustion chamber at different times. To better understand this phenomenon, it was used a RCM, that is able to control, more easily, relevant parameters such as compression ratio, temperatures, pressures, injection times etc. As a second fuel, which partially replaces the diesel, which is traditionally used in compression ignition engines, it was used the ethanol. The RCM was then adapted to receive two systems for direct injection into the combustion chamber. Studies have shown that different forms of injection of the two fuels produce very different processes to the same amount of fuel injected. The results are presented in the form of indicated pressure as a function of position. Heat released and ignition delay are also presented. Experiments were conducted for one or two injections of ethanol per cycle at different times. High substitution rates of the fossil fuel were obtained when compared to injections of external mixtures of diesel and ethanol or fumigation technique, where the second fuel is mixed externally with the combustion air.
6
Alqahtani, Ali Mubark. "Computational studies of homogeneous charge compression ignition, spark ignition and opposed piston single cylinder engines." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7899/.
Full textAbstract:
In this research, possible improvements in engine specifications using the simulations developed on the AVL BOOST™ and Ricardo WAVE™ platforms were investigated. These modelling simulations help the author to predict the effect of any improvements in engine specifications without practical experimental challenges and difficulties. Firstly, HCCI and SI engines were modelled with the intention of maximizing the engine’s efficiency and minimizing the emissions. Changes of valve timing and throttle angle influence emissions’ reduction and the efficiency of the engine. In SI engines, the emissions of NOx can be reduced by using EGR, while only having a little effect on performance. The emissions from the HCCI, due to their intrinsically low emission output, were not improved. The effect of increasing the bore to stroke ratio in an opposed piston engine whilst maintaining a constant swept volume, port geometry and combustion timing, shows an increase of heat losses due to the lower ratio of exposed surface area to volume; an increase in thermal and mechanical efficiency; and most importantly, an improvement in fuel consumption. Also, in this research study, different strategies for opposed piston engines were investigated to increase the engine’s efficiency. The effect of a variable compression ratio on an opposed piston engine’s performance indicates different behaviour at various engine speeds and under different running conditions.
7
Sullivan, Morgen Paul. "Study of lubrication oil ignition in a rapid compression machine under sporadic pre-ignition conditions." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100352.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 95-97).
In recent years, the industry has shifted toward down-sizing and turbo-charging spark ignition (SI) engines in an effort to increase fuel conversion efficiency. However, this has given rise to a destructive phenomenon known as sporadic pre-ignition (SPI). At low cranking speeds and high loads, engines have been observed to knock violently for brief and infrequent intervals. If allowed to continue, these periods of knock will result in a destroyed engine. This study looks at the propensity of lube oil vapor appearing in the cylinder as a cause for this phenomenon. The theory is that a local oil vapor/air mixture pocket may auto-ignite and start a flame in the charge. The pre-ignition would produce extreme knock. A rapid compression machine (RCM) was used to simulate this scenario and determine if oil vapor can cause SPI, and if so, to relate the auto-ignition tendency to the oil properties. The RCM was used to measure the ignition delay of a cloud of oil vapor in a stoichiometric gasoline/air mixture. The ignition delays were then correlated to chemical and physical properties of the oils. Finally, the effect of diluting the mixture was assessed. The results suggest that lube oil is a plausible source of SPI. The oil ignition delay times are sufficiently short to produce extreme pre-ignition consistent with SPI. Further supporting evidence lies in the fact that oil ignition delay times concur with SPI behavior in engines. It was found that the base stock, degradation, and chemical additives all play a role in oil ignition delay times. The results also demonstrate. that dilution significantly slows auto-ignition of the oil.
by Morgen Paul Sullivan.
S.M.
8
Angelos, John P. (John Phillip). "Fuel effects in homogeneous charge compression ignition (HCCI) engines." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50615.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.Includes bibliographical references (p. 209-217).
Homogenous-charge, compression-ignition (HCCI) combustion is a new method of burning fuel in internal combustion (IC) engines. In an HCCI engine, the fuel and air are premixed prior to combustion, like in a spark-ignition (SI) engine. However, rather than using a spark to initiate combustion, the mixture is ignited through compression only, as in a compression-ignition (CI) engine; this makes combustion in HCCI engines much more sensitive to fuel chemistry than in traditional IC engines. The union of SI- and CI-technologies gives HCCI engines substantial efficiency and emissions advantages. However, one major challenge preventing significant commercialization of HCCI technology is its small operating range compared to traditional IC engines. This project examined the effects of fuel chemistry on the size of the HCCI operating region, with an emphasis on the low-load limit (LLL) of HCCI operability. If commercialized, HCCI engines will have to operate using standard commercial fuels. Therefore investigating the impact of fuel chemistry variations in commercial gasolines on the HCCI operability limits is critical to determining the fate of HCCI commercialization. To examine these effects, the operating ranges of 12 gasolines were mapped in a naturally-aspirated, single-cylinder HCCI engine, which used negative valve overlap to induce HCCI combustion. The fuels were blended from commercial refinery streams to span the range of market-typical variability in aromatic, ethanol, and olefin concentrations, RON, and volatility. The results indicated that all fuels achieved nearly equal operating ranges. The LLL of HCCI operability was completely insensitive to fuel chemistry, within experimental measurement error. The high-load limit showed minor fuel effects, but the trends in fuel performance were not consistent across all the speeds studied. These results suggest that fuel sensitivity is not an obstacle to auto-makers and/or fuel companies to introducing HCCI technology.
(cont.) Developing an understanding of what causes an HCCI engine to misfire allows for estimation of how fuel chemistry and engine operating conditions affect the LLL. The underlying physics of a misfire were studied with an HCCI simulation tool (MITES), which used detailed chemical kinetics to model the combustion process. MITES was used to establish the minimum ignition temperature (Tmisfire) and full-cycle, steady-state temperature (Tss) for a fuel as a function of residual fraction. Comparison of Tmisfire and Tss near the misfire limit showed that Tss approaches Tmisfire quite closely (to within ~ 14 K), suggesting that the primary cause of a misfire is insufficient thermal energy needed to sustain combustion for multiple cycles. With this relationship, the effects of engine speed and fuel chemistry on the LLL were examined. Reducing the engine speed caused a reduction in T, which allowed fuel chemistry effects to be more apparent. This effect was also observed experimentally with 2 primary reference fuels (PRFs): PRF60 and PRF90. At 1000 RPM, PRF60 obtained a substantially lower (~30%) LLL than PRF90, but at speeds >/= 1500 RPM, fuel ignitability had no effect on the LLL. Fuel chemistry was shown to influence the LLL by increasing both Tmisfire and Tss for more auto-ignition resistant fuels. However, the extent to which fuel chemistry affects these temperatures may not be equivalent. Therefore, the relative movement of each temperature determines the extent to which fuel chemistry impacts the LLL.
by John P. Angelos.
Ph.D.
9
Bhave, Amit. "Stochastic reactor models for homogeneous charge compression ignition engines." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616153.
Full text
10
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.
Full textAbstract:
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
11
Kawambwa, S. J. M. "Performance and combustion of ethanol in a high-compression, direct-injection, compression-ignition engine." Thesis, University of Surrey, 1993. http://epubs.surrey.ac.uk/981/.
Full text
12
Ayala, Ferran A. (Ferran Alberto) 1976. "Data base generation and modeling of Homogeneous Charge Compression Ignition using a rapid compression machine." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/88882.
Full text
13
Röhl, Olaf [Verfasser]. "Low Temperature Chemistry in Gasoline Compression Ignition Engines / Olaf Röhl." Aachen : Shaker, 2010. http://d-nb.info/1120864054/34.
Full text
14
Hong, Guang. "Feedback control of transient smoke emissions from compression ignition engines." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304278.
Full text
15
Al, Qahtani Yasser. "Particulate matter characterization and control in premixed compression ignition engines." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7187/.
Full textAbstract:
The tests were conducted on a 2.2 L, four-cylinder Ford Puma engine running on a Premixed Compression Ignition (PCI) mode and at steady state. Hot EGR was introduced for fuels, G75 and naphtha and it significantly reduced the total particle number and mass concentrations by about 99% and the mean diameter to a smaller size ~ 10 nm compared to diesel fuel. Single injection reduced the total particle numbers’ concentration and smoke of both fuels G75 and naphtha by about 99%. Also, the total carbon (TC) was reduced by more than 54% for G75 and naphtha fuels compared to diesel fuel. The double injection strategy was flexible than the single injection. It reduced the total particle numbers’ concentration and smoke of G75 and naphtha fuels by about 99.80% at low and medium loads, also the total concentration of PAHs was reduced by more than 90% compared to single injected diesel fuel. For G75 fuel, double injection reduced the total concentration of alkanes by 60%, while single injection reduced the total concentration of cycloalkanes by 54% compared to other fuels.
16
Kontarakis, George A. "Homogeneous charge compression ignition in four-stroke internal combustion engines." Thesis, University of Cambridge, 2001. https://www.repository.cam.ac.uk/handle/1810/272293.
Full text
17
Resor, Michael Irvin. "COMPUTATIONAL INVESTIGATION OF ROTARY ENGINE HOMOGENEOUS CHARGE COMPRESSION IGNITION FEASIBILITY." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1419010366.
Full text
18
Materego, Myeji Chrysostom. "Auto-ignition characterisation of synthetic fuels via Rapid Compression Machine." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/12929/.
Full textAbstract:
Availability and sustainability of fuels for road and air transport is essential for economic development and growth of any nation. New alternative fuels provide an opportunity to limit the use of ever declining conventional petroleum oil reserves as well as offsetting CO2 generation from their use. Liquid fuels have the highest energy density for transportation applications and synthetic liquid fuels, which can be produced from renewable non-food bio feedstock offer an exciting opportunity for partial or even total substitution of remaining fossil fuel supplies. It is therefore of great interest to study the fundamental combustion characteristics of these fuels if they are to be used commercially. This work is aiming at characterising the auto-ignition properties of individual fuel components representative of the chemical families present in the synthetic fuels which in this case are toluene, iso-octane, n-heptane, and bio-alcohols; ethanol and n-butanol. The auto-ignition characterisation was made by measurements of ignition delay times, τ. The time τ for these fuels and their blends were measured after rapidly compressed to an elevated pressure and temperature using a Rapid Compression Machine (RCM). RCM provides good platform to study the fuel auto-ignition process without complicated physical effects in engines which are continually changing. However, they are not without problems, practical applications are usually not within the ideal conditions. Different machines have different extent of deviation from ideal conditions, making comparison of results between rigs difficult. In the present study, a dedicated work was conducted to study the difference between the measurements originated from these rigs and were characterised against their deviations from ideal conditions. These cover chemical reaction during the finite compression time, the effects of heat loss during the ignition delay period, the effects of piston displacement (piston bounce), and non-homogeneous auto-ignition. An interesting aspect of the study is that a plot of the measured different delay times at a given temperature, on the separate machines, against the corresponding degrees of reaction during compression, when extrapolated to zero reaction, yield a more accurate delay time for that condition. As the temperature is increased, so also are the oscillatory pressure amplitudes generated at the auto-igniting hot spots. This is in line with other studies of hot spot auto-ignition. Measurements of ignition delay times of different chemical groups separately and when blended with each other were made. They provided an understanding of how their interaction influences the overall ignition delay times. When blended the change of their τ values do not vary linearly especially when the blended components have large difference in reactivities. Toluene for example, which is commonly known for its long ignition delay times, was made extremely reactive when blended with n-butanol. Comparison of addition of bio-alcohols (ethanol and n-butanol) on gasoline surrogate fuel (TRF) showed that at lower temperatures, they both increased the ignition delay times of TRF, while at high temperatures they reduced TRF delay times to almost the same value. n-butanol started to reduce TRF delay times at lower temperatures compared to ethanol. Development of auto-ignition blending laws offers an opportunity to enable quick methods for choosing an appropriate blend for a particular application. In this work, a Linear by Mole (LbM) auto-ignition blending law was proposed, it uses the measured ignition delay times of individual components in the blend and varies them linearly with the fractional concentration of each component. This was found to be satisfactory only for blends of chemical families without NTC behaviour such as CH4/H2, for fuels with NTC behaviour an empirical based law was generated for the conditions studied. Overall, this study has broadened our understanding in auto-ignition behaviour of selected individual fuel components and their blends at varying conditions of pressure, temperature and concentration. It has also enabled substantial development of Leeds RCM to achieve fast compression with good piston damping.
19
Karagiorgis, Stelios. "Dynamic modeling and transient control of Homogeneous Charge Compression Ignition engines." Thesis, University of Cambridge, 2008. https://www.repository.cam.ac.uk/handle/1810/252072.
Full text
20
Antunes, Jorge Manuel Gomes. "The use of hydrogen as a fuel for compression ignition engines." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1365.
Full textAbstract:
The objective of this research was to investigate the applicability of hydrogen as a fuel for compression ignition engines. The research indicates that hydrogen is a suitable fuel for “compression ignition” (CI) engines, “fumigated diesel” (FD), “homogeneous charge compression ignition” (HCCI) and “direct injection of hydrogen” (DIH2). Peculiarities of the various modes of operation with hydrogen were investigated using a high speed commercial direct injection diesel engine, Deutz 1FL 511 with a compression ratio of 17:1, as well as a simulation model to assist with on the understanding of certain phenomena that were impossible to reproduce due to the engine and transducers physical limitations. Instrumentation with high-speed data acquisition was designed and installed to measure crankshaft speed and position, airflow rate, inlet air pressure and temperature, fuel consumption, brake power, cylinder combustion pressure, and exhaust gas temperature. The design, construction and characterization of a pulse controlled hydrogen injection system for HCCI and DIH2 was carried out and discussed. In this research, special attention was paid to characterize and identify the operating parameters that control the hydrogen combustion in a CI engine. High rates of engine cylinder pressure rise were found when using hydrogen and some form of control solution is required. Simulation and engine tests were carried out to characterize and identify new design approaches to control such high rates of pressure rise, culminating in the proposal of a pulsed injection methodology, and also the use of the Miller cycle to mitigate the observed high rates of pressure rise. A number of possible iv innovative solutions and measures, making the hydrogen engine operation reliable and safe are also presented.
21
CCACYA, ANTHONY OSWALDO ROQUE. "EXPERIMENTAL STUDY OF HOMOGENEOUS MIXTURE COMPRESSION IGNITION IN INTERNAL COMBUSTION ENGINES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2010. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=17159@1.
Full textAbstract:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCom o intuito de reduzir as emissões e melhorar a combustão em uma maior faixa de rotação e carga de um motor, foi proposto o estudo da combustão por compressão de misturas homogêneas (HCCI), este processo apresenta altas eficiências e baixas emissões, principalmente de NOx e fuligem. Assim, o objetivo do presente trabalho é a determinação das faixas de operação estável em um motor diesel, de alta taxa de compressão (20:1). O combustível utilizado foi gasolina tipo A, tendo em vista a sua grande produção, além das características de auto-ignição. Para atingir o objetivo proposto foram controladas a temperatura de entrada do ar e a quantidade de combustível da mistura, o que foi implementado sem modificação estrutural do motor. Os ensaios foram realizados com uma temperatura de alimentação entre 75 e 95 ºC, com rotação entre 1200 e 2200 RPM. Os valores para o fator lambda variaram, em função de um processo de combustão estável, entre 2 e 4. São apresentados os resultados experimentais obtidos em um dinamômetro de bancada, sobre os quais se fez uma análise do rendimento, para a faixa de melhor estabilidade da combustão. Para a mesma faixa foi realizada uma análise das curvas de pressão x tempo, caracterizando a auto-ignição como função da temperatura do ar e da riqueza da mistura. Os melhores rendimentos encontrados situam-se ao redor de 36,5 %, para uma temperatura de ingresso de 85 °C, para as maiores rotações pesquisadas.
The present study of homogeneous mixture compression ignition (HCCI) was proposed in order to reduce emissions and improve combustion at a higher speed range and load, this process has high efficiency and low emissions mainly NOx and soot. Therefore, the aim of this study was to determine the ranges of stable operation in a diesel engine of high compression ratio (20:1), operating in HCCI. The fuel used was gasoline type A, given its large production, besides the good characteristics of auto-ignition. To achieve this purpose were controlled inlet air temperature and the amount of fuel in the mixture, these were implemented without structural modification of the engine. The tests were conducted with a feed temperature between 75 and 95 ° C, with rotation between 1200 and 2200 RPM. The values for the lambda factor varied between 2 and 4, as a function of a stable combustion process. The experimental results here reported were obtained on a dynamometer bench, on which, it was made a performance analysis for the better stability combustion range. Additionally for this range, an analysis of the curves of pressure vs. time was performed, characterizing the auto-ignition as a function of air temperature and the richness of the mixture. The best results found are located around 36.5% at an intake temperature of 85 ° C for the highest speed studied.
22
Park, Pyongwan. "Rapid compression machine measurements of ignition delays for primary reference fuels." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14068.
Full text
23
Fang, Ming. "Analysis of Variability and Injection Optimization of a Compression Ignition Engine." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250532113.
Full text
24
Oak, Sushil Shreekant. "Second law analysis of premixed compression ignition combustion in a diesel engine using a thermodynamic engine cycle simulation." Texas A&M University, 2008. http://hdl.handle.net/1969.1/86040.
Full textAbstract:
A second law analysis of compression ignition engine was completed using a thermodynamic engine cycle simulation. The major components of availability destruction and transfer for an entire engine cycle were identified and the influence of mode of combustion, injection timing and EGR on availability balance was evaluated.
The simulation pressure data was matched with the available experimental pressure data gathered from the tests on the Isuzu 1.7 L direct injection diesel engine. Various input parameters of the simulation were changed to represent actual engine conditions.
Availability destruction due to combustion decreases with advanced injection timing and under premixed compression ignition (PCI) modes; but it is found to be insensitive to the level of EGR. Similarly, trends (or lack of trends) in the other components of availability balance were identified for variation in injection timing, EGR level and mode of combustion. Optimum strategy for efficient combustion processes was proposed based on the observed trends.
25
White, Timothy Ross Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Simultaneous diesel and natural gas injection for dual-fuelling compression-ignition engines." Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/25233.
Full textAbstract:
The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.
26
Wu, Ning. "Autoignition and emission characteristics of gaseous fuel direct-injection compression-ignition combustion." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/357.
Full textAbstract:
Heavy-duty natural gas engines offer air pollution and energy diversity benefits. However, current homogeneous-charge lean-burn engines suffer from impaired efficiency and high unburned fuel emissions. Natural gas direct-injection engines offer the potential of diesel-like efficiencies, but require further research. To improve understanding of the autoignition and emission characteristics of natural gas direct-injection compression-ignition combustion, the effects of key operating parameters (including injection pressure, injection duration, and pre-combustion temperature) and gaseous fuel composition(including the effects of ethane, hydrogen and nitrogen addition) were studied.
An experimental investigation was carried out on a shock tube facility. Ignition delay, ignition kernel location, and NOx emissions were measured. The results indicated that the addition of ethane to the fuel resulted in a decrease in ignition delay and a significant increase in NOx emissions. The addition of hydrogen to the fuel resulted in a decrease in ignition delay and a significant decrease in NOx emissions. Diluting the fuel with nitrogen resulted in an increase in ignition delay and a significant decrease in NOx emissions. Increasing pre-combustion temperature resulted in a significant reduction in ignition delay, and a significant increase in NOx emissions. Modest increase in injection pressure reduced the ignition delay; increasing injection pressure resulted in higher NOx emissions. The effects of ethane, hydrogen, and nitrogen addition on the ignition delay of methane were also successfully predicted by FlameMaster simulation.
OH radical distribution in the flame was visualized utilizing Planar Laser Induced Fluorescence (PLIF). Single-shot OH-PLIF images revealed the stochastic nature of the autoignition process of non-premixed methane jets. Examination of the convergence of the ensemble-averaged OH-PLIF images showed that increasing the number of repeat experiments was the most effective way to achieve a more converged result.
A combustion model, which incorporated the Conditional Source-term Estimation(CSE) method for the closure of the chemical source term and the Trajectory Generated Low-Dimensional Manifold (TGLDM) method for the reduction of detailed chemistry, was applied to predict the OH distribution in a combusting non-premixed methane jet. The model failed to predict the OH distribution as indicated by the ensemble-averaged OH-PLIF images, since it cannot account for fluctuations in either turbulence or chemistry.
27
Constandinides, George. "Thermal management and control of a homogeneous charge compression ignition (HCCI) engine." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4900/.
Full textAbstract:
HCCI is the process which a relatively homogeneous mixture of air and fuel auto ignites through compression. HCCI engines can have high thermodynamic cycle efficiencies, with low levels of emissions of nitrogen oxides (NOx) and particulate matter (PM). However due to the nature of the combustion the operating envelope is quite small compared to conventional internal combustion engines. A powertrain system centred on a supercharged HCCI engine with on-board thermal management was developed that extends the operating envelope of an HCCI engine. To achieve controlled auto-ignition across a wide range of engine conditions, a system for management of flow and temperature was installed at the air intake to enable the necessary regulation of temperatures and pressures at the inlet ports. The system includes a heat exchanger to heat the charge air, a supercharger to boost the charge air pressure, supercharger bypass and finally an intercooler, so that a wide range of combinations of pressures and temperatures can be achieved at the intake ports. In order to facilitate this control, a complete simulation model of the thermal system for a pressure-boosted multi-cylinder HCCI engine was developed. The model implements a dynamic mass and enthalpy balance model running in real time for the air intake system of the multi-cylinder HCCI gasoline engine and auxiliary components. The model is capable to calculate heat flux, mass flow, pressure and gas temperature distribution for the whole engine thermal management system however it does not take into account the turbulent nature of flow especially where hot and cold gas mix. Therefore an elaborate CFD model of the Thermal Management system has been compiled for evaluation of the computed flow field and analysis of the thermal system performance by the use of the CFD tool ANSYS CFX.
28
Su, Haiyun. "Stochastic reactor models for simulating direct injection homogeneous charge compression ignition engines." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608887.
Full text
29
Crawford, Morgan H. "Feasibility and Emissions of Compression Ignition Engines Fueled with Waste Vegetable Oil." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000193.
Full text
30
Islam, Muhammad Aminul. "Microalgae: An alternative source of biodiesel for the compression ignition (CI) engine." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/79551/4/Muhammad%20Aminul%20Islam%20Thesis.pdf.
Full textAbstract:
This thesis is a comprehensive study of microalgae biodiesel for the compression ignition engine. It examines microalgae growing conditions, the extraction process and physiochemical properties with a wide range of microalgae species. It also evaluates microalgae biodiesel with regards to engine performance and emission characteristics and explains the difficulties and potentiality of microalgae as a biodiesel. In doing so, an extensive analysis of different extraction methods and engine testing was conducted and a comprehensive study on microalgae biodiesel is presented.
31
Lin, Wei. "The Ignition of Methane and Coal Dust by Air Compression - The Experimental Proof." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36740.
Full textAbstract:
When a large area of open gob collapses suddenly, a windblast is produced that can cause considerable damage throughout the infrastructure of a mine. In a few cases, the windblast has been accompanied by ignitions of methane and/or coal dust. Analytical and numerical analyses investigated the transient behavior of the air through the small time period during which the roof is falling. This is sufficiently short to allow adiabatic compression of the air, i.e. negligible heat transfer to rock surfaces. Controlled escape of the air via interconnecting entries limits the build-up of air pressure. However, this same phenomenum causes the potential energy of the falling strata to be concentrated into a diminishing mass of air. Computer simulations predicted that the temperature of the air would increase rapidly as the roof descends, reaching values that are capable of igniting either methane or coal dust.
This thesis concentrates on a series of laboratory tests involving the compression of mixtures of air, methane and coal dust under a falling weight and while allowing controlled escape of the mixture. The transient responses on pressure and temperature sensors were recorded. In addition to an analysis of those records, the thesis highlights those conditions in which ignitions occurred.Master of Science
32
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.
Full textAbstract:
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.
33
Birger, Nicholas Joseph. "Flow characteristics of gas-blast fuel injectors for direct-injection compression-ignition engines." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/25752.
Full textAbstract:
Natural gas has a high auto-ignition temperature, therefore natural gas engines use an
ignition source to promote combustion. The high-pressure direction-injection (HPDI)
systems available use small diesel injections prior to the main gas injection. A new series
of HPDI injectors have been developed that inject diesel and gas simultaneously through
the same holes. In order to understand and control injection and combustion behavior in
an engine, it is essential to understand how injection mass is related to the diesel/gas ratio
and injection command parameters.
Three prototype injectors are examined. “Prototype B” most closely resembles a standard
J36 HPDI injector, but has a modified diesel needle that injects diesel internally into a
common diesel/gas reservoir. Prototypes “CS & CSX” have the diesel needle eliminated
and replaced with a flow restrictor. The pressure difference between the diesel and the
gas controls the quantity of diesel injected. A single pulse width (GPW) for the gas
needle controls the fuel quantities.
An injection visualization chamber (IVC) was developed for flow measurements and
optical characterization of injections into a chamber at pressures up to 80 bar. Diesel and
natural gas are replaced by VISCOR® and nitrogen to study non-reacting flows. A novel
feature of the IVC is a retracting shroud that allows the injector to reach steady-state prior
to imaging.
For low commanded injection duration (GPW less than 0.60 ms), the relation between
GPW and injected mass is non-linear, for all injectors tested. For gas pulse widths greater
than 0.65 ms the Co-injectors exhibit approximately linear behavior with higher diesel
fuelling quantities lowering gas flow quantities. All Co-injectors are compared to
baseline gas flow quantities of a standard J36 to show design difference effects on flow
quantities. The sensitivity of gas flow to diesel in injection quantities, as well as the
discharge coefficient are computed and theoretically modeled for each prototype. Results
suggest differing diesel/gas distributions, dependent on method of diesel introduction and
actuator response.
Imaging indicates the mechanical delay of the injectors is independent of chamber
backpressure but dependent on fuel supply pressure. However, gas injection quantities
are increased by higher chamber backpressure. Changes in the gas/liquid ratio are
reflected in different jet image characteristics. These results are compared to theory using
an AMESim model developed for an existing production injector.
34
Namasivayam, Ashand Mitra. "Combustion, performance and emissions characteristics of compression-ignition engines fuelled by sustainable fuels." Thesis, Queen Mary, University of London, 2011. http://qmro.qmul.ac.uk/xmlui/handle/123456789/668.
Full textAbstract:
Internal combustion engines are approaching their theoretical maximum efficiency, which could indicate limited future technological improvements in performance and exhaust emissions with standard fuels. In addition, fossil fuel dependence can only be reduced by implementing appropriate renewable fuel sources. The experimental investigation in this work only concerns the compression-ignition (CI) engine combustion process both in normal operation and “dual-fuel” operation. The dual-fuel mode allows low-cetane number fuel to be used in CI engines, with a “pilot” fuel spray injection of high-cetane number fuel to provide ignition. Initially, rapeseed methyl ester (RME) and two water-in-RME emulsions were compared with normal diesel fuel during normal operation. Neat RME generally performed similarly to diesel fuel, while giving higher specific fuel consumption (SFC) levels. Both water- in-RME emulsions performed fairly similarly to neat RME. This suggests that the cooling effect of water vapourisation was a negligible factor throughout the operating range. Natural gas dual-fuel operation reduced NOx at certain conditions and overall CO2 emissions while thermal efficiencies were maintained compared with normal operation. However, significantly higher unburnt hydrocarbons (HC) and CO emissions were recorded at low and intermediate engine loads. For the emulsified pilot fuels, better fuel-air mixing (possibly as a result of “microexplosions”) increased NOx after an equivalence ratio of about 0.6. Hydrogen dual-fuel operation generally increased NOx emissions while CO2 emissions were reduced compared with normal operation. Thermal efficiencies remained comparable for all pilot fuels. NOx emissions in the emulsified fuel cases were generally comparable to the neat RME pilot. Lower volumetric efficiency was also recorded, while power output was limited to maintain engine stability and avoid abnormal combustion caused by excessively high pressure-rise rates (called “hydrogen knock”). Overall, significant optimisation is needed to improve combustion efficiency at low and intermediate engine loads during dual-fuel CI engine operation. As these engines are designed specifically for liquid fuels, substantial engine customisation or even complete redesign (particularly in the fuel supply system) is needed to improve the combustion quality on a scale larger than that seen in this work.
35
PRADELLE, FLORIAN ALAIN YANNICK. "USE OF BIOFUELS IN COMPRESSION IGNITION ENGINES: POTENTIAL OF DIESEL-BIODIESEL-ETHANOL BLENDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29914@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
PROGRAMA DE EXCELENCIA ACADEMICA
BOLSA NOTA 10
Para substituir parcialmente a demanda em óleo diesel de origem fóssil, reduzir os elevados custos de importação e respeitar as normas ambientais, políticas sustentáveis já levaram a substituir parcialmente óleo diesel por biodiesel. Entretanto, outras tecnologias, como as misturas diesel-biodiesel-etanol, estão sendo investigadas. O principal desafio dessas misturas consiste em melhorar a miscibilidade e a estabilidade do álcool no óleo diesel. No presente trabalho, formulou-se um aditivo original, a partir de compostos renováveis, que permitiu melhorar a faixa de concentração de etanol anidro dentro de óleo diesel com 15 por cento em volume de biodiesel e de temperatura onde observa-se misturas estáveis. Diversas propriedades físico-químicas das misturas aditivadas foram medidas em uma larga faixa de concentração de etanol para avaliar os aspetos de consumo, qualidade da combustão, comportamento a baixa temperatura, interação entre fluido e superfície, e segurança. Os resultados obtidos mostraram que misturas com, pelo menos, 1,0 por cento em volume de aditivo e até 20 por cento em volume de etanol anidro são estáveis para temperaturas superiores a 10 graus Celsius e respeitam a maioria das especificações brasileiras atuais para óleo diesel. Ensaios experimentais em um motor de ignição por compressão MWM 4.10 TCA (Euro III) foram realizados com estas misturas. Os resultados obtidos mostraram que a substituição do óleo diesel altera as características da combustão: o crescente teor de etanol leva ao aumento do atraso de ignição, à liberação de calor mais rápida e à diminuição da pressão máxima. Mesmo nessas condições não otimizadas de injeção e de combustão, os resultados mostraram uma melhor conversão da energia química no etanol para produzir potência efetiva, comparado com os valores encontrados nos motores flex fuel de ciclo Otto, além de um pequeno aumento no rendimento térmico do motor.
In order to partially replace the demand of fossil diesel fuels, to reduce high import costs and to comply with environmental standards, sustainable policies have led to partially replace diesel fuel by biodiesel. However, other technologies, such as diesel-biodiesel-ethanol mixtures, are being investigated. The major challenge of these mixtures is to improve the miscibility and the stability of alcohol in diesel fuel. In this study, an original additive, from renewable compounds, improved the miscibility of anhydrous ethanol in diesel fuel with 15 per cent by volume of biodiesel and temperature in which stable mixtures were observed. Several physicochemical properties of the additivated mixtures were measured in a large range of ethanol concentration to evaluate aspects of consumption, combustion quality, behavior at low temperature, interaction between the fluid and the surface, and safety. The results showed that blends with, at least 1.0 per cent, by volume of additive and 20 per cent by volume of anhydrous ethanol are stable at temperatures above 10 degrees Celsius and respected most of the current Brazilian specifications for diesel fuel. Experimental tests on a compression ignition engine MWM 4.10 TCA (Euro III) were performed with these mixtures. The results showed that the diesel fuel substitution alters the characteristics of combustion: the increased ethanol content implied an increase of the ignition delay, a faster heat release and a decrease of maximum pressure. Despite these non-optimized conditions for injection and combustion, results showed a better conversion of ethanol chemical energy into brake power, in comparison to the values found in flex fuel spark ignition engine, in addition to a small increase in the indicated efficiency of the engine.
36
Luszcz, Pawel. "Combustion diagnostics in Homogeneous Charge Compression Ignition optical and thermal single cylinder engines." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/524/.
Full textAbstract:
The work presented in this thesis is intended to investigate the effects of fuel properties, injection strategy and timing on autoignition and combustion characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine with a negative valve overlap (NVO) strategy. Conventional (pressure-transducer based) measurements and passive optical research have contributed to understanding of the chemical-physical sites of HCCI autoignition and combustion. This experimental work was undertaken on matching thermal and optical single cylinder research engines in configurations derived from a production Jaguar V8 engine. A thermal engine study using a range of fuels including conventional gasoline and primary reference fuels has been performed to gain insight into autoignition and combustion characteristics of various chemically dissimilar blends or components. This was done at different operating conditions by varying the engine speed and the proportion of residuals trapped. These measurements have shown that the autoignition and combustion characteristic of an HCCI operated engine are highly dependent on fuel blend composition and are also affected by engine operating conditions. It was found that the autoignition process type which the mixture undergoes, whether it is one- or two-step, depends very strongly both on fuel blend composition and on engine operating conditions. More specifically the presence and also proportion of particular chemical compounds in a blend could significantly contribute to the alteration of the process type. Similar experiments using the chosen engine operating points were repeated on the optical engine using passive optical diagnostics such as imaging and spectroscopy. Thereby it was possible to gain insight into the chemistry of one-step and two- step ignition processes. The image analysis of the port fuel injected (PFI) HCCI operation have been carried out for stoichiometric and lean conditions. A crank-angle resolved high-speed imaging technique was employed a piston crown window for optical access to the combustion chamber. The spatial repeatability nature of autoignition occurrence and the directions of combustion progress were evaluated using especially developed image processing technique. The insight into the expansion rates of burned areas and of the spreading velocities of reacting structures fronts was also gained by introducing two new image processing techniques. Various direct injection strategies (single and split injection) and timings, including fuel injection prior to and during the negative valve overlap period were optically investigated. The comprehensive study included the application of three diagnostic instruments: the Complementary Metal-Oxide Semiconductor (CMOS) high-speed colour imager, the intensified Charge Couple Device (CCD) and the imaging spectrograph. Among the other observations the applied passive techniques, the imaging and the spectroscopy in conjunction with adequate image processing techniques have shown that the combustion behaviour and also the colour of the burning mixture are dependent on the fuel injection scheme. With the investigated split (double) injection, when some of fuel is injected prior to TDC NVO the combustion behaviour is significantly different than when it is injected during even at TDC (NVO). There is a strong indication that a form of incandescence occurs during the NVO, which probably comes from the glowing soot. This is further supported by a quantification of the emitted luminescence and spectroscopic measurements during this phase.
37
Fayad, Mohammed Ali. "Particulate Matter (PM) characteristics from compression ignition diesel engines operated by renewable fuels." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7919/.
Full textAbstract:
Diesel engine emission of particulate matter (PM) is one of the most critical issues which have a large impact on the environmental and human health. The use of renewable fuels (biodiesel and butanol blend) and aftertreatment systems in diesel engines are the main requirements for reducing and controlling the pollutant emissions. To understand the effect of alternative fuels on PM characteristics and a diesel oxidation catalyst (DOC), rapeseed oil methyl ester (RME) biodiesel and an alcohol blend (butanol-diesel blend) were used for various engine operating conditions. The results revealed that the combustion of alternative fuels produces lower emissions of unburnt hydrocarbons (UHC), carbon monoxide (CO), and PM number concentration, which enhanced the catalyst activity at lower temperatures. Studying the effect of oxygenated fuel and fuel injection strategies on the combustion characteristics and PM characteristics, and hence the catalyst’s performance, can unveil synergies that can benefit vehicle emissions and fuel economy, as well as guide the design of the next generation of sustainable fuels. It was found that post-injection incorporation with a butanol blend produced lower PM concentration and modified the soot’s morphological parameters by reducing number of primary particles (npo), the radius of gyration (Rg), and the fractal dimension (Df).
38
Scaringe, Robert J. (Robert Joseph). "Extension of the high load limit in the Homogeneous Charge Compression Ignition engine." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50585.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 120-121).
The Homogeneous Charge Compression Ignition (HCCI) engine offers diesel-like efficiency with very low soot and NOx emissions. In a HCCI engine, a premixed charge of air, fuel and burned gas is compressed to achieve autoigntion. Combustion occurs throughout the chamber volume resulting in short overall burn duration. This short burn duration can cause excessively high pressure rise rates which lead to unacceptable engine noise and potentially reduced engine life. To combat this high pressure rise rate the engine must be operating with significant diluent, either excess air or burned exhaust gas. However this high level of dilution limits the specific output of the HCCI engine to levels far below spark ignition or diesel engines. The high load limit is a major challenge for the HCCI engine. This study utilized a single cylinder research to examine the high load limit and possible methods to extend it. The details of the high load limit were first explored across a range of intake temperatures, boost pressures, trapped residual fractions, equivalence ratios and external EGR ratios for a gasoline fueled HCCI engine. A significant finding was that the high load limit always occurs at the misfire limit and that for a given pressure rise rate constraint, the high load limit occurs at lowest possible intake pressure and trapped residual fraction needed to prevent misfire. A possible means to allow operation at higher boost pressures is to utilize cooled external EGR or to reduce the intake temperature. For a given burn fraction, increasing the EGR rate or reducing the intake temperature provided reduced MPRR.
(cont.) However with these changes, the misfire limit also shifted such that the value of the maximum load does not materially change. Thus boosting coupled with EGR or intake temperature reduction can not be used to significantly extend the high load limit. A correlation was developed for the burn duration. Multi-zone combustion simulations were used to confirm the form of this correlation. The multi-zone based correlations were then used to quantitatively examine the potential of thermal stratification as a means to extend the high load limit. It was shown that for a doubling of the width of the in-cylinder temperature distribution, a 30% increase in the high load limit is possible.
by Robert J. Scaringe.
Ph.D.
39
Johns, R. A. "The analysis of the combustion of methanol in lean-burning, high-compression engines using an engine combustion model." Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/847267/.
Full textAbstract:
Alcohol fuels are expected to become an economic/strategic alternative to oil over the next decade as oil reserves are depleted and countries seek to become more energy self-sufficient. Methanol, produced from natural gas deposits, and ethanol, produced locally by distillation of biomass, offer easily transportable alternatives. The use of a wider range of fuels in spark-ignition engines and the quest for fuel economy whilst meeting exhaust emissions legislation are important issues in engine design. The performance of current and proposed combustion chamber designs needs to be assessed with lean mixtures of both conventional and alternative fuels. The parameters defining combustion chamber performance, initial flame development and cycle-to-cycle variations in combustion may be readily determined using computer in-cylinder combustion models in a diagnostic manner to reduce experimentally acquired cylinder pressure data. This thesis develops and applies two analysis techniques to the study of the combustion of methanol in the lean burning regime with experimental results from three engines. The pressure increment technique, in which the pressure rise owing to combustion at constant volume is computed, is suitable for use directly on microcomputer systems. The two-zone equilibrium theory model, in which the mass burnt to give the measured pressure rise is evaluated, provides a more comprehensive analysis but is demanding in computer power. Higher burning rates were achieved using highly turbulent combustion chambers with methanol and equivalence ratios could be leaned to about 0.8 before cycle-to-cycle variations in combustion limited stable operation. The results obtained indicated the significant phases of initial flame development, the influence of early flame development on subsequent burning rates, and the influence of differing chamber geometries on performance. The combustion process was modelled for use in parametric studies of engine performance based on empirical data.
40
Thoo, Wei Jet. "A study of the ignition delay characteristics of combustion in a compression ignition engine operating on blended mixtures of diesel and gasoline." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32843/.
Full textAbstract:
The interest to study diesel-gasoline fuel mix for CI engine combustion had been motivated by the higher thermal efficiency of CI engine compared to SI engine which gasoline normally runs in and the report of having lower NOx and PM emissions for gasoline combustion in CI engine. The experimental CI engine was unable to run on 100% gasoline but able to run on gasoline blend as high as G80 with default SOI timing setting. 100% gasoline would not run despite it contains only 20% more gasoline than G80 due to its extremely longer ignition delay caused by the exponential increase of gasoline blend’s ID. Engine brake thermal efficiencies of all gasoline blends tested up to G80 were comparable and averaged at 24.2%, 33.8% and 39.8% for engine speed-load conditions of 2000rev/min 2.5bar BMEP, 2000rev/min 5bar BMEP and 2000rev/min 8.5bar BMEP, accordingly. This finding confirmed that gasoline blend could be a new alternative fuel that offers comparable performance to the liquid fuel market for CI engine. In Europe, diesel blended with a small percentage of biodiesel or ethanol has been common to liquid fuel market. The study focused on ID that was closely correlated to NOx and soot formations in engine cylinder instead of NOx and PM emissions at tailpipe. The longer ID of 100% gasoline in relative to diesel could go up to 14CAD resulted in increased proportion of premixed combustion to mixing-controlled combustion at the rate of 40 Joule per CAD increase in ID. This incremental premixed combustion proportion was ideal for low NOx and soot formations in CI engine. ID was able to be discriminated into physical delay, a period dictated by engine speed-load conditions and controlled fuel breakup, fuel vaporisation and fuel-air mixing; and chemical delay, a period dictated by fuel chemical kinetic mechanism and controlled the amount of heat released. This finding gave valuable insight to the fact that proportion of premixed combustion and mixing-controlled combustion were controlled by chemical delay. Zero-dimensional theoretical combustion study with chemical kinetic mechanism confirmed that the exponential increased ID trend of gasoline blends was attributed to chemical delay. Hence a gasoline blend close to 100% gasoline would have very lean premixed combustion and small mixing-combustion which correlated to very low NOx and soot formations in cylinder. In order to understand the NOx and soot formations in cylinder in detail, a 73species reduced chemical kinetic mechanism that could represent gasoline blend combustion in CFD was developed. This reduced chemical kinetic mechanism could be used for future CFD work to understand effect of interactions between physical processes (fuel breakup, fuel vaporisation and fuel-air mixing) and chemical processes (activation of fuel combustion chemistry) on NOx and soot formations in cylinder. This work founded an effective semi-automatic reduction methodology with MATLAB algorithms for developing the 73species CFD-compatible reduced chemical kinetic mechanism of gasoline blends. This platform made building a surrogate fuel’s reduced chemical kinetic mechanism from multiple detailed chemical kinetic mechanisms of single component fuels fast, accessible and friendly to users of all background. DRG reduction technique had been enhanced by the multiple-stage ROP and multiple-step DRG approaches. The multiple-stage ROP and multiple-step approaches increased the species size reduction of chemical kinetic mechanisms by additional 8% and 13.5%, accordingly. The additional species size reduction capability of both approaches would be beneficial for the reduction of chemical kinetic mechanism for CFD use which is practically limited to size of 100species for feasible computational errors and speed. Apart from the limitation for the percentage of gasoline blend that could be used in the experimental CI engine, the lower compressibility of gasoline blends in relative to diesel had caused the SOI timing to be retarded up to 3CAD in this pump-triggered type of injection system. This shift of combustion phase had no significant effect on the ID and heat-release characteristics. The combustion phase shift can be easily compensated by advancing the SOI accordingly.
41
Bhari, Anil. "A Rapid Compression Machine with the Novel Concept of Crevice Containment." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1294677850.
Full text
42
Paolucci, Lorenzo. "High efficiency low temperature combustion in compression ignition engines for automotive and aeronautical applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
Internal combustion engines are increasingly subject to ever more stringent and severe Euro-legislations about pollutants emissions in terms of nitrogen oxide, carbon monoxide, unburned hydrocarbons and soot. In last years, thanks to advanced after treatment systems and technological innovations, emission have been improved but, due to even higher costs and complexity of such systems and in a view of further emissions restrictions, advanced combustion methods leading to cleaner and improved efficiency combustion are under investigation. A possible path to follow in order to met requirements on lower emissions, is relative to so called low temperature combustion: a group of innovative combustion methods which by exploiting lean and premixed combustion decreases significantly flame temperature which is mainly responsible for nitrogen oxide production. This work of thesis focus on preliminary study, development and experimental testing of a low temperature combustion strategy, namely "gasoline direct compression ignition" also known as "GDCI".
43
Laforet, Christopher A. "Combustion of natural gas with entrained diesel in a heavy-duty compression-ignition engine." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/17010.
Full textAbstract:
High-pressure direct-injection of natural gas for use in compression-ignition engines has been found to reduce emissions without sacrificing performance relative to pure diesel operation. In the present work, prototype ‘co-injectors’ which inject a diesel and natural gas mixture from a single injector were tested in a heavy-duty, 6-cylinder Cummins ISX engine with 5 cylinders disabled. One prototype (‘B’) was tested under low-speed, low-load conditions, to determine the effects of fuel flows and in-cylinder conditions on the combustion characteristics of co-injection. Co-injector B, and a second prototype (Co-injector CS: A variation of Co-injector B which mixes the fuels differently) were tested at three engine modes using two injections per cycle to determine the effect of the duration of the first injection on emissions and combustion characteristics. The performance of the co-injectors was compared to Westport Innovation’s High Pressure Direct Injection (HPDI) J36 injector to determine if co-injection can produce comparable emissions.
Single injection tests carried out with Co-injector B at 800 RPM over a range of diesel flows, gas flows, injection pressures, and cylinder temperatures & pressures were used to generate response surfaces for knock intensity, ignition delay, and combustion efficiency.
It was found that diesel flow and the cylinder pressure at the time of injection had the largest effect of knock intensity and ignition delay, and that the knock/ignition delay relationship in co-injection is inverse.
The double injection tests showed that the difference in diesel distributions within the gas plenums of CS and B results in more diesel being injected during the first injection in CS compared to B, which supports previous results. It was found that short first pulses resulted in the lowest emissions for both co-injectors, and that with low first gas pulse widths the performance of the co-injectors is comparable to that of Westport’s HPDI-J36 injector.
44
Kevric, Arman. "Combustion characteristics of a compression ignition engine running on biodiesel and gasoline blended fuels." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605993.
Full textAbstract:
An experimental investigation of the effects of fuel composition on the ignition delay and heat release characteristics of a light duty, automotive compression ignition engine has been carried out. The ignition delay is defined as the period between the start of the main fuel injection event and the start of combustion (SOC). The research has covered a range of fuel types and blends to maximise the effects of composition on the ignition delay and heat release. The fuels used were diesel, gasoline and FAME (Fatty Acid Methyl Esters) produced from rapeseed oil, coconut oil and waste cooking oil. All the engine test studies were carried out using a 2.4 litre displacement, direct injection Ford Puma engine, at test conditions representing low load, mid load and high load at 2000rpm, with EGR rates of up to 35%. Single equation, semi-empirical ignition delay models based upon the Arrhenius equation were studied and developed to fit the experimental ignition delay data, and thus incorporate fuel composition effects. Fuel composition is shown to affect the duration of the ignition delay, but after the start of combustion the heat release characteristics, for a given energy supplied in fuel, proved to be relatively insensitive to fuel composition effects. The premixed fraction is shown to be directly proportional to the ignition delay. The ignition delay of biodiesel fuel is up to 15% shorter than diesel while a gasoline blend of 50% gasoline/50% diesel lengthens the ignition delay by up to 30% with respect to diesel. These differences in the ignition delay affect the engine thermal efficiency by up to 2% due to combustion phasing effects. Gasoline fuel blended up to 80% (by volume) with diesel was combusted successfully, resembling PCCI (Premixed Charged Compression Ignition) combustion regimes, while biodiesel fuel types RME (Rapeseed Methyl Esters), CME (Coconut Methyl Esters) and WCO (Waste Cooking Oil Methyl Esters) all showed differences in heat release characteristics due to ignition delay differences. Calibration changes are necessary to compensate for the fuel composition effects on the ignition delay and subsequent combustion characteristics. An engine specific, single equation ignition delay model was developed that successfully described the experimental ignition delay data over the fuel range of fuel composition: rID = 4.32p-l.02/'P-O.2exp (:;) where EA = A.Kevric University of Nottingham , ' )t8186 . Based upon the analysis of combustion characteristics of the experimental CN+ZS) data, the initial form of a universal ignition delay model was developed, composing of a physical delay portion and a chemical delay portion. A.
45
Peucheret, Steven. "Exhaust gas reforming of natural gas to aid homogeneous charge compression ignition engine combustion." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420510.
Full text
46
GUEDES, ANDREW DAVID MENDES. "EXPERIMENTAL STUDY ABOUT ETHANOL IMPACT IN DIESEL-BIODIESEL-ETHANOL BLENDS IN COMPRESSION IGNITION ENGINES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=30923@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROAGÊNCIA NACIONAL DE PETRÓLEO
Há algum tempo biocombustíveis renováveis são potenciais soluções sugeridas às questões de emissão de poluentes e dependência da sociedade aos derivados fósseis. Biodiesel e etanol são combustíveis comerciais renováveis candidatos à substituição das fontes fósseis, especialmente, em motores de ignição por compressão, os quais são tipicamente mais eficientes do que aqueles de ignição por centelha. Misturas ternárias de diesel, biodiesel e etanol formam estratégias de substituição parcial do diesel aplicáveis em motores de ignição por compressão sem a necessidade de grandes adaptações. Nesta dissertação realizaram-se avaliações experimentais em um motor multi-cilíndrico de ignição por compressão (MWM 4.10 TCA), abastecido com misturas de diesel, biodiesel (até 15 por cento em teor volumétrico) e etanol anidro (até 20 por cento em teor volumétrico). Cada mistura ternária é composta por diferentes proporções do álcool e sempre com a concentração volumétrica de 1 por cento de um aditivo estabilizador da mistura. Portanto, os testes associam substituições parciais do diesel por biocombustíveis a avaliações de desempenho do motor e da combustão das misturas, sob algumas condições de carga, regimes de rotação e instantes de injeção de combustível. Os testes realizados indicam que misturas com 20 por cento em volume de concentração de etanol experimentam inícios de combustão até 4,7 graus CA mais atrasados. Porém, a busca de instantes otimizados na injeção de combustível trouxe melhorias ao desempenho do motor, permitiu conversões energéticas mais vantajosas do etanol na ignição por compressão frente à ignição por centelha, além de minimizar efeitos do etanol em retardar o início da combustão.
Renewable biofuels have been proposed for a long time as an alternative to the issues concerned to pollutants emission and also society s liability to fossil fuels. Biodiesel and ethanol are renewable commercial fuel candidates for fossil fuels substitution, especially, in compression ignition engines, which are typically more efficient than the spark ignition ones. Diesel s partial replacement, such as the substitution by ternary blends formed by diesel, biodiesel and ethanol, is a strategy applicable to compression ignition engines without the need of further modifications. In this dissertation tests were run in a multi-cylinder compression ignition engine (MWM 4.10 TCA), fueled with diesel, biodiesel (up to 15 percent in volumetric content) and anhydrous ethanol (up to 20 percent in volumetric content) blends. Each mixture should be composed by different alcohol s proportions and always containing a 1 percent volumetric concentration of additive in order to ensure ternary s blend stability. Therefore, tests try to ally diesel s partial replacement by biofuels with engine performance and blends combustion assessment, under some combinations of load, engine speed and injection timing conditions. The tests performed indicate that the start of the combustion experienced up to 4.7 degrees CA postponements, when fueled with a 20 percent ethanol volumetric concentration blend. Still, optimized injection timing investigation brought improvements to engine performance, allowed better ethanol energetic conversions through compression ignition when compared to spark ignition and could also minimize delays caused by ethanol s presence in the beginning of the combustion.
47
Norouzi, Shahrouz. "Interaction of diesel type fuels and engine fuel system components in compression ignition engines." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5369/.
Full textAbstract:
Contact of fuels with engine components at low and elevated temperatures for various amounts of time is found to be challenging as this contact has several effects on engine fuel system components and fuels. Also, storage of fuels for a long period of time is found to have almost the same effect on both engine components and fuels upon engine use. In this thesis fuel and engine components’ contact have been studied for four typical metals used in the construction of many engine fuel systems; in form of pure or alloys (copper, aluminium, mild carbon steel and stainless steel), studied after contact with three of the currently available fuels for use in compression ignition engines. Ultra-low sulphur diesel fuel (ULSD) was used as the fossil fuel, rapeseed methyl ester (RME) as the first generation biofuel and finally gas-to-liquid (GTL) as the second generation of biofuel, obtained via the Fischer-Tropsch process. The investigation was performed in different sections: fuels and metals have been studied for any degradation after contact at low and high temperatures for short and long exposure times, and an understanding of the corrosion process and any degradation on both metals and fuels has been achieved; due to the high hygroscopic character of these fuels and the presence of possible impurities in the fuel, the investigation was extended for analysis of the effect of the presence or absence of absorbed water and dissolved air (in the form of Oxygen) in fuels on degradation and corrosion characteristics of these fuels.
48
Andreae, Morgan M. (Morgan MacKenzie). "Effect of ambient conditions and fuel properties on homogeneous charge compression ignition engine operation." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35616.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 197-198).
Practical application of Homogeneous Charge Compression Ignition (HCCI) combustion must demonstrate robust responses to variations in environmental conditions. This work examines the impact of ambient conditions and fuel changes on HCCI engine operation, and evaluates cam phasing as a mechanism to compensate for these changes. Experiments were carried out on a modified 2.3 L 14 production engine, and HCCI operation was achieved by the use of residual trapping by negative valve overlap. The first phase of the project examined the impact of changes in intake air temperature and humidity on HCCI operation. Exhaust cam phasing was used to control load, and intake cam phasing was use to produce a change in combustion phasing. Cam timing control was largely able to compensate for changes in combustion due to changes in air temperature and humidity. Higher intake air temperature advanced combustion phasing and resulted in a 1 bar reduction of the net indicated mean effective pressure (NIMEP) at the high load limit for lower engine speeds. Intake air temperature did have more of an impact during lean operation. Higher intake air humidity delayed combustion phasing.
(cont.) During stoichiometric operation, this delay allowed a small extension (a few tenths of a bar in NIMEP) in the high load limit. During lean operation, the delay in combustion timing resulted in a reduction of the high load limit. The second phase of the project examined the impact of market fuel composition variations on HCCI operation. Twelve test fuels were created to vary the composition of 5 fuel properties: Research Octane Number (RON), Reid Vapor Pressure (RVP), olefin content, aromatic content, and ethanol content. The test fuels were blends of different commercial refinery streams and contained hundreds of different hydrocarbons to be representative market gasolines. Fuel type was found to have only a small impact on the HCCI operating range, and cam phasing was largely able to compensate for changes in fuel composition. The main effect of the different fuel composition appeared to be differences in ignition delay.
by Morgan M. Andreae.
Ph.D.
49
Korkmaz, Metin [Verfasser]. "Experimental Investigation of Advanced Low-Temperature Combustion Concepts for Compression Ignition Engines / Metin Korkmaz." Düren : Shaker, 2021. http://d-nb.info/1229779345/34.
Full text
50
Schönborn, A. "Influence of the molecular structure of biofuels on combustion in a compression ignition engine." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18674/.
Full textAbstract:
This thesis presents an experimental study on the influence of the molecular structure of potential biofuels on combustion in a compression ignition engine. The molecular structure of a fuel is amongst the most fundamental parameter controlling its physical and chemical characteristics, and is thus critical to the combustion process within an engine. The approach employed in this work was to study the combustion of several individual molecules in a series of experiments whilst varying a single feature of the molecular structure at a time. This yielded information about how a particular structural feature of a molecule affects the combustion process. During the course of this project, a special fuel injection system was developed, which allowed the injection of small fuel samples into the engine at high pressure. This allowed tests to be carried out on purposely synthesised fuel samples that were only obtainable in small quantities. Detailed studies on the combustion of fatty alkyl esters (commonly termed biodiesel), acetals, ethers and alcohols were conducted. The combustion chamber pressure of the engine, the energy release of combustion, the engine efficiency, the exhaust gas composition and the emission of particulate matter were measured and analysed. It was observed that in the diffusion combustion of biofuels, the emission of nitrogen oxides from the engine depend primarily on the ignition delay of the fuel, which governs the combustion stoichiometry and peak cylinder pressures and temperatures within the combustion chamber, and secondly on the adiabatic flame temperature of the biofuels. It was found that the number of double bonds present in biofuel molecules correlated with the amount of particulate mass emitted from the engine. It was further observed that oxygenated biofuels such as fatty acid alkyl esters, acetals, ethers and alcohols produced much lower levels of particulate mass from their combustion than petroleum-derived diesel fuel. The emission of particulates depended on the fuel oxygen content, as well as on the boiling point of the fuel. Combustion experiments conducted in homogeneous charge compression ignition combustion demonstrated that ethers of low molecular mass could be amongst the most-suited liquid fuel molecules for this type of combustion method.