Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Alexander H. Levis, Paul K. Houpt, Stamatios K. Andreadakis. / Bibliography: p. 26. / "June 1984"

Report submitted to the Office of Energy R & D Policy, National Science Foundation

Report submitted to the Office of Energy R & D Policy, National Science Foundation

Report submitted to the Office of Energy R & D Policy, National Science Foundation

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.

O trabalho apresenta uma análise técnica de desempenho dos motores de combustão interna ciclo Diesel, operando com combustível biodiesel em relação à operação com óleo diesel automotivo do tipo B. Busca-se neste trabalho definir uma relação tecnológica entre o antigo (óleo diesel) e o novo (biodiesel), demonstrando-se formas e processos de operação com ambos, a fim de enfatizar a garantia de eficiência da aplicação do biodiesel nos motores que hoje operam com óleo diesel automotivo. O desempenho foi avaliado em relação ao torque, potência, consumo específico de combustível e emissões de fumaça. A aplicação do biodiesel como uma nova forma de energia alternativa, sem alterações em projetos originais dos motores de combustão interna ciclo Diesel, motivou a realização deste trabalho. O motor utilizado nestes ensaios foi um motor Agrale M93 ID, monocilíndrico, com cilindrada de 668 cm³ e relação de compressão de 20,0:1. Neste motor foram ensaiados três tipos diferentes de biodiesel: o de soja, mamona e dendê. Todos os ensaios foram realizados utilizando-se percentuais específicos de adição de biodiesel ao óleo diesel. Utilizou-se inicialmente o B25 (adição de 25% de biodiesel ao óleo diesel tipo B), e posteriormente concentrações de B50, B75 e B100. Todo o sistema motriz foi instalado em uma bancada dinamométrica e instrumentado, a fim de permitir a coleta de informações e avaliações do torque, potência, consumo específico, emissões de fumaça, temperaturas e rotações operação. Os ensaios foram desenvolvidos em velocidades de rotação de 2600, 2400, 2200, 2000 e 1800 min-¹, para cada uma das concentrações de biodiesel e óleo diesel, coletando-se posteriormente todos os dados necessários para aplicar no programa de correção, conforme normatização vigente. Os resultados apresentaram pequenas variações nos parâmetros torque e potência, com variações mais significativas para o consumo específico e emissões de fumaça. Observa-se ao final dos ensaios que a aplicação de biodiesel destas três oleaginosas não altera o funcionamento do motor até percentuais próximos a 25%. Para misturas acima de 50%, verifica-se que o motor ensaiado apresenta reduções mais significativas nos parâmetros torque e potência, com aumento considerável no consumo específico de combustível e redução expressiva nas emissões de fumaça. / This study presents a Diesel cycle internal combustion engine technical analysis of performance operating on biodiesel fuel compared to the operation using type B automotive diesel oil. The aim of the study is to define the technological relationship between the long-standing diesel oil and the new biodiesel, demonstrating ways and processes of operation with both of them, so as to emphasize the guarantee of efficient application of biodiesel in engines which presently operate on automotive diesel oil. The performance was evaluated in relation to torque, power, specific fuel consumption and smoke emissions. The application of biodiesel as a new form of alternative energy, with no alterations in original cycle Diesel internal combustion engine projects, motivated this study. The engine used for the tests was a single-cylinder Agrale M93 ID, with 668 cc and 20,0:1 compression ratio. Three different types of biodiesel were tested in that engine: from soybeans, from castor oil plant (mamona) and from dende palm tree. All tests were carried out using specific percentages of biodiesel addition to the diesel oil. Initially, B25 (addition of 25% of biodiesel to the B type diesel oil) was tested, and then concentrations of B50, B75 and B100 were used. The whole engine system was installed and instrumented on a dynamometric bench, so as to allow the data collecting to record information and evaluations on torque, power, specific fuel consumption, smoke emissions, temperature and operating rotations. The tests were performed on rotation speeds of 2600, 2400, 2200, 2000 and 1800 min-¹, for each of the concentrations of biodiesel and diesel oil, obtaining all the necessary data to apply in the correction program, according to the present norms. The results presented little variation for the torque and power parameters and more significant variations for specific fuel consumption and smoke emissions. After testing, we observed that the application of biodiesel from those three oleaginous plants does not alter engine operation with percentages around 25%; for mixtures above 50%, the engine tested presented more significant reductions in torque and power parameters, with a considerable increase in specific fuel consumption and a substantial reduction in smoke emissions.

The GDI engine has a number of practical advantages over the more traditional port-fuel injection strategy, however a number of challenges remain the subject of continued research in an attempt to fully exploit the advantages of the GDI engine. These include complex in-cylinder flow fields and fuel-air mixing strategies, and significant temporal variation, both through an engine cycle and on a cycle-by-cycle basis. Despite advances in experimental techniques, the relative difficulty and cost of taking detailed measurements remains high, thus computational techniques are an integral part of research activities. The research work presented in this thesis has focused on the use of detailed 3D-CFD techniques for investigating physical phenomena of the in-cylinder flow field and fuel injection process in a single cylinder GDI engine with early injection event. A detailed validation of the numerical predictions of the in-cylinder flow field using both the RANS RNG k-ε turbulence model and the Smagorinsky LES SGS turbulence model was completed with both models showing good agreement against available experimental results. A detailed validation of the numerical predictions of the fuel injection process using a Lagrangian DDM and both RANS RNG k-ε turbulence model and Smagorinsky LES SGS turbulence model was completed with both models showing excellent agreement against experimental data. The model was then used to investigate the in-cylinder flow field and fuel injection process including research into: the three dimensional nature of the flow field; intake valve jet flapping, characterisation, causality and CCV, and whether it could account for CCV of the mixture field at spark timing; the anisotropic characteristics of the flow field using both the fluctuating velocity and turbulence intensity, including the increase in anisotropy due to the fuel injection event; the use of POD for quantitatively analysing the in-cylinder flow field; investigations into the intake valve, cylinder liner and piston crown spray plume impingement processes, including the use of a multi-component fuel surrogate and CCV of the formed liquid film; characterisation and CCV of the mixture field though the intake and compression strokes up to spark timing. Finally, the predicted turbulence characteristics were used to evaluate the resultant premixed turbulent combustion event using combustion regime diagrams.

O trabalho apresenta uma análise técnica de desempenho dos motores de combustão interna ciclo Diesel, operando com combustível biodiesel em relação à operação com óleo diesel automotivo do tipo B. Busca-se neste trabalho definir uma relação tecnológica entre o antigo (óleo diesel) e o novo (biodiesel), demonstrando-se formas e processos de operação com ambos, a fim de enfatizar a garantia de eficiência da aplicação do biodiesel nos motores que hoje operam com óleo diesel automotivo. O desempenho foi avaliado em relação ao torque, potência, consumo específico de combustível e emissões de fumaça. A aplicação do biodiesel como uma nova forma de energia alternativa, sem alterações em projetos originais dos motores de combustão interna ciclo Diesel, motivou a realização deste trabalho. O motor utilizado nestes ensaios foi um motor Agrale M93 ID, monocilíndrico, com cilindrada de 668 cm³ e relação de compressão de 20,0:1. Neste motor foram ensaiados três tipos diferentes de biodiesel: o de soja, mamona e dendê. Todos os ensaios foram realizados utilizando-se percentuais específicos de adição de biodiesel ao óleo diesel. Utilizou-se inicialmente o B25 (adição de 25% de biodiesel ao óleo diesel tipo B), e posteriormente concentrações de B50, B75 e B100. Todo o sistema motriz foi instalado em uma bancada dinamométrica e instrumentado, a fim de permitir a coleta de informações e avaliações do torque, potência, consumo específico, emissões de fumaça, temperaturas e rotações operação. Os ensaios foram desenvolvidos em velocidades de rotação de 2600, 2400, 2200, 2000 e 1800 min-¹, para cada uma das concentrações de biodiesel e óleo diesel, coletando-se posteriormente todos os dados necessários para aplicar no programa de correção, conforme normatização vigente. Os resultados apresentaram pequenas variações nos parâmetros torque e potência, com variações mais significativas para o consumo específico e emissões de fumaça. Observa-se ao final dos ensaios que a aplicação de biodiesel destas três oleaginosas não altera o funcionamento do motor até percentuais próximos a 25%. Para misturas acima de 50%, verifica-se que o motor ensaiado apresenta reduções mais significativas nos parâmetros torque e potência, com aumento considerável no consumo específico de combustível e redução expressiva nas emissões de fumaça. / This study presents a Diesel cycle internal combustion engine technical analysis of performance operating on biodiesel fuel compared to the operation using type B automotive diesel oil. The aim of the study is to define the technological relationship between the long-standing diesel oil and the new biodiesel, demonstrating ways and processes of operation with both of them, so as to emphasize the guarantee of efficient application of biodiesel in engines which presently operate on automotive diesel oil. The performance was evaluated in relation to torque, power, specific fuel consumption and smoke emissions. The application of biodiesel as a new form of alternative energy, with no alterations in original cycle Diesel internal combustion engine projects, motivated this study. The engine used for the tests was a single-cylinder Agrale M93 ID, with 668 cc and 20,0:1 compression ratio. Three different types of biodiesel were tested in that engine: from soybeans, from castor oil plant (mamona) and from dende palm tree. All tests were carried out using specific percentages of biodiesel addition to the diesel oil. Initially, B25 (addition of 25% of biodiesel to the B type diesel oil) was tested, and then concentrations of B50, B75 and B100 were used. The whole engine system was installed and instrumented on a dynamometric bench, so as to allow the data collecting to record information and evaluations on torque, power, specific fuel consumption, smoke emissions, temperature and operating rotations. The tests were performed on rotation speeds of 2600, 2400, 2200, 2000 and 1800 min-¹, for each of the concentrations of biodiesel and diesel oil, obtaining all the necessary data to apply in the correction program, according to the present norms. The results presented little variation for the torque and power parameters and more significant variations for specific fuel consumption and smoke emissions. After testing, we observed that the application of biodiesel from those three oleaginous plants does not alter engine operation with percentages around 25%; for mixtures above 50%, the engine tested presented more significant reductions in torque and power parameters, with a considerable increase in specific fuel consumption and a substantial reduction in smoke emissions.

O trabalho apresenta uma análise técnica de desempenho dos motores de combustão interna ciclo Diesel, operando com combustível biodiesel em relação à operação com óleo diesel automotivo do tipo B. Busca-se neste trabalho definir uma relação tecnológica entre o antigo (óleo diesel) e o novo (biodiesel), demonstrando-se formas e processos de operação com ambos, a fim de enfatizar a garantia de eficiência da aplicação do biodiesel nos motores que hoje operam com óleo diesel automotivo. O desempenho foi avaliado em relação ao torque, potência, consumo específico de combustível e emissões de fumaça. A aplicação do biodiesel como uma nova forma de energia alternativa, sem alterações em projetos originais dos motores de combustão interna ciclo Diesel, motivou a realização deste trabalho. O motor utilizado nestes ensaios foi um motor Agrale M93 ID, monocilíndrico, com cilindrada de 668 cm³ e relação de compressão de 20,0:1. Neste motor foram ensaiados três tipos diferentes de biodiesel: o de soja, mamona e dendê. Todos os ensaios foram realizados utilizando-se percentuais específicos de adição de biodiesel ao óleo diesel. Utilizou-se inicialmente o B25 (adição de 25% de biodiesel ao óleo diesel tipo B), e posteriormente concentrações de B50, B75 e B100. Todo o sistema motriz foi instalado em uma bancada dinamométrica e instrumentado, a fim de permitir a coleta de informações e avaliações do torque, potência, consumo específico, emissões de fumaça, temperaturas e rotações operação. Os ensaios foram desenvolvidos em velocidades de rotação de 2600, 2400, 2200, 2000 e 1800 min-¹, para cada uma das concentrações de biodiesel e óleo diesel, coletando-se posteriormente todos os dados necessários para aplicar no programa de correção, conforme normatização vigente. Os resultados apresentaram pequenas variações nos parâmetros torque e potência, com variações mais significativas para o consumo específico e emissões de fumaça. Observa-se ao final dos ensaios que a aplicação de biodiesel destas três oleaginosas não altera o funcionamento do motor até percentuais próximos a 25%. Para misturas acima de 50%, verifica-se que o motor ensaiado apresenta reduções mais significativas nos parâmetros torque e potência, com aumento considerável no consumo específico de combustível e redução expressiva nas emissões de fumaça. / This study presents a Diesel cycle internal combustion engine technical analysis of performance operating on biodiesel fuel compared to the operation using type B automotive diesel oil. The aim of the study is to define the technological relationship between the long-standing diesel oil and the new biodiesel, demonstrating ways and processes of operation with both of them, so as to emphasize the guarantee of efficient application of biodiesel in engines which presently operate on automotive diesel oil. The performance was evaluated in relation to torque, power, specific fuel consumption and smoke emissions. The application of biodiesel as a new form of alternative energy, with no alterations in original cycle Diesel internal combustion engine projects, motivated this study. The engine used for the tests was a single-cylinder Agrale M93 ID, with 668 cc and 20,0:1 compression ratio. Three different types of biodiesel were tested in that engine: from soybeans, from castor oil plant (mamona) and from dende palm tree. All tests were carried out using specific percentages of biodiesel addition to the diesel oil. Initially, B25 (addition of 25% of biodiesel to the B type diesel oil) was tested, and then concentrations of B50, B75 and B100 were used. The whole engine system was installed and instrumented on a dynamometric bench, so as to allow the data collecting to record information and evaluations on torque, power, specific fuel consumption, smoke emissions, temperature and operating rotations. The tests were performed on rotation speeds of 2600, 2400, 2200, 2000 and 1800 min-¹, for each of the concentrations of biodiesel and diesel oil, obtaining all the necessary data to apply in the correction program, according to the present norms. The results presented little variation for the torque and power parameters and more significant variations for specific fuel consumption and smoke emissions. After testing, we observed that the application of biodiesel from those three oleaginous plants does not alter engine operation with percentages around 25%; for mixtures above 50%, the engine tested presented more significant reductions in torque and power parameters, with a considerable increase in specific fuel consumption and a substantial reduction in smoke emissions.