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<p> This thesis presents a strategy for documenting real-time control systems, and the work products that result from its application to the development of an alternate fuel injection controller. In doing so, this document contributes technically to the areas of automotive control, and control systems documentation. The strategy was not developed independently of the control system, but in a manner which reflects its size and complexity.</p> <p> The controller is used to generate and transmit appropriately timed and sized pulses to an alternative fuel injector array, and switch auxiliary devices including a fuel heater, and an injector lock-off. Such a controller, when used to inject natural gas or propane into a gasoline burning engine, provides a reduction in both engine operating costs and harmful engine emissions.</p> <p> The controller stores a fuel map that relates the amount of energy released by the combustion of petroleum to that released by the combustion of an alternate fuel, over a range of varying environmental conditions. The fuel map is used to calculate the length of alternate injection pulses. These maps have been designed by, and are the property of Cosimo's Garage Ltd. and thus will not appear in this document.</p> <p> At present, nearly all large engine car conversion technology is more rigid than the solution provided here. Conversion costs are often prohibitive and problems requiring professional service are frequent. Should the controller described here, help to curb conversion costs and reduce the need for frequent service as is expected, the controller will be a viable candidate for production and sale.</p> / Thesis / Master of Applied Science (MASc)

A flush-wall injector model and a strut injector model representative of state of the art scramjet engine combustion chambers were experimentally studied in a cold-flow (non-combusting) environment to determine their fuel-air mixing behavior under different operating conditions. The experiments were run at nominal freestream Mach numbers of 2 and 4, which simulates combustor conditions for nominal flight Mach numbers of 5 and 10. The flush-wall injector model consists of sixteen inclined, round, sonic injectors distributed around the wall of a circular duct. The strut injector model has sixteen inclined, round, sonic injectors distributed across four struts within a circular duct. The struts are slender, inclined at a low angle to minimize drag, and have two injectors on each side. The experiments investigated the effects of injectant molecular weight, freestream Mach number, and jet-to-freestream momentum flux ratio on the fuel-air mixing process. Helium, methane, and air injectants were studied to vary the injectant molecular weight over the range of 4-29. All of these experiments were performed to support the needs of an integrated experimental and computational research program, which has the goal of upgrading the turbulence models that are used for Computational Fluid Dynamics predictions of the flow inside a scramjet combustor. The primary goals of this study were to use injector models that represent state of the art scramjet engine combustion chambers to provide validation data to support the development of turbulence model upgrades and to add to the sparse database of mixing results in such configurations. The main experimental results showed that higher molecular weight injectants had approximately the same amount of penetration in the far field as lower molecular weight injectants at the same jet-to-freestream momentum flux ratio. Higher molecular weight injectants also demonstrated a mixing rate that was the same as or slower than lower molecular weight injectants depending on the flow conditions. A comparison of the experimental results for the two different injector models revealed that the flush-wall injector mixed significantly faster than the strut injector in all of the experimental cases. / Ph. D.

Active control of combustion instabilities through secondary fuel injection is a control method that has gained a lot of attention in the past decade. Previous control schemes with acoustic loudspeakers are not practical in full-scale gas turbines due to the extreme temperatures and acoustic power requirements. Much work has gone into controlling these thermoacoustic instabilities with secondary fuel control. Control of a laminar premixed tube combustor through secondary fuel actuation is the concentration of this work. It is the first known published attempt to control a laminar premixed tube combustor through secondary fuel actuation. Due to the low flow rates within the tube combustor an innovative injection technique had to be constructed to perform the secondary fuel actuation. The gaseous fuel is injected only one millimeter above the location of the flame through one, two, or four injectors. These injectors were designed to overcome the serious problem of pulse diffusion. This technique enabled the tube combustor to be controlled through secondary fuel injection. Accompanying the innovative fuel injection technique is a duty cycle modulation technique that was a prime contributor to the success of the control system. This method enabled the system to be controlled at conditions that were uncontrollable with a fixed duty cycle. The overall result was a 35 dB suppression of the limit cycle amplitude with 20% secondary fuel injection. / Master of Science

O motor a álcool pré-vaporizado tem potencial para ser uma alternativa mais eficiente e menos poluente aos motores a álcool convencionais. Nele, o combustível é vaporizado com calor rejeitado pelo próprio motor e admitido na fase gasosa, aproveitando-se das vantagens dos motores com combustíveis nessa fase sem alguns dos seus inconvenientes. O projeto foi aperfeiçoado buscando viabilidade técnica e econômica para sua instalação em veículos automotores. Água do sistema de arrefecimento cede calor para a ebulição do combustível. As novas tecnologias para injeção de combustíveis gasosos contribuem para esse objetivo, bem como o desenvolvimento de um sistema sustentável e auto-ajustável de geração de vapor de etanol que usa a água do sistema de arrefecimento. Conseguiu-se maior eficiência em quase todos os regimes de funcionamento estudados, bem como meios de reduzir as principais emissões automotivas indesejáveis. / Pre-vaporized ethanol engine (PVEE) has potential to be more efficient and less pollutant than conventional ethanol-powered engines. In it, fuel is vaporized with heat rejected by engine itself and intook in gaseous form, taking advantage of this kind of fuel but without some of its inconveniences. The PVEE project was polished looking for economical and technical liability to future use in automotive vehicles. New gaseous fuel injection technologies contribute to this goal, together the development of a sustainable and self-adjustable ethanol vapor generating system who uses water from engine\'s cooling systems. Better efficiency was achieved in almost all investigated regimes, as well as were found ways to reduce the main undesirable automotive emissions.

O sistema de gerenciamento dos motores automotivos tem se tornado um avançado sistema de controle. Seu objetivo é fazer com que o nível de emissões de gases poluentes gerados esteja dentro dos padrões exigidos pela legislação de cada país e ao mesmo tempo manter os níveis de desempenho e dirigibilidade. Apresenta as principais características de um típico sistema de gerenciamento de motores a combustão interna, descreve os modos de controle e aponta tendências futuras. Descreve o sistema de controle desenvolvido, o qual servirá de ferramenta de pesquisa para trabalhos que envolvam o estudo de técnicas de controle aplicadas neste contexto e pesquisas envolvendo otimização do rendimento dos motores automotivos / The automotive engine management system has become an advanced control system. Its objective is to maintain the pollutants gas emissions according to legislations and to maintain the performance and driveability, at the same time. It presents the main features of a tipical internal combustion engine management system, it describes the control modes and it point out the future tendencies. It describes the control system developed, which one will be usefull as a tool for research involving control applied in this context and engine automotive efficiency optimization researchs

A scramjet inlet was designed for use on a small scale, Mach six, ethylene-fuelled vehicle. The inlet used strut-based cantilevered fuel injectors and a well-defined mixing duct to mix fuel prior to the combustor. Designed using theoretical and numerical analyses, the resulting inlet configuration consisted of a single body shock inlet with vertical fuel injector struts and four cantilevered injectors per strut side. This inlet was 80 cm long and 42 cm high. Numerical analysis of the vehicle was conducted with computational fluid dynamics by solving the Favre-Averaged Navier-Stokes equations; turbulence was simulated using the Wilcox k-ω model. Multispecies simulations in two and three dimensions were used to evaluate the design. Analysis of the simulated flow features, thrust potential and mixing efficiency demonstrated favourable vehicle performance. In particular, the inlet allowed for complete combustion when lean equivalence ratios of less than 0.7 were used.

A scramjet inlet was designed for use on a small scale, Mach six, ethylene-fuelled vehicle. The inlet used strut-based cantilevered fuel injectors and a well-defined mixing duct to mix fuel prior to the combustor. Designed using theoretical and numerical analyses, the resulting inlet configuration consisted of a single body shock inlet with vertical fuel injector struts and four cantilevered injectors per strut side. This inlet was 80 cm long and 42 cm high. Numerical analysis of the vehicle was conducted with computational fluid dynamics by solving the Favre-Averaged Navier-Stokes equations; turbulence was simulated using the Wilcox k-ω model. Multispecies simulations in two and three dimensions were used to evaluate the design. Analysis of the simulated flow features, thrust potential and mixing efficiency demonstrated favourable vehicle performance. In particular, the inlet allowed for complete combustion when lean equivalence ratios of less than 0.7 were used.

The aim of this research is to develop an optimisation tool to support the preliminary design of gas turbine combustors by providing a partial automation of the design process. This tool is to enable better design to be obtained faster, providing a reduction in the development costs and time to market of new engines. The first phase of this work involved the analysis of the combustor design process with the aim of identifying the critical tasks that are suitable for being automated and most importantly identifying the key parameters describing the performance of a combustor. During the second phase of this work an adequate design methodology for this problem was defined. This led to the development of a design optimisation Toolbox based on genetic algorithms, containing the tools required for it's proper integration into the combustor preliminary design environment. For the development of this Toolbox, extensive work was performed on genetic algorithms and derived techniques in order to provide the most efficient and robust optimisation method possible. The optimisation capability of the Toolbox was first validated and metered on analytical problems of known solution, where it demonstrated excellent optimisation performance especially for higher-dimensional problems. In a second step of the testing and validation process the combustor design capability of the Toolbox was demonstrated by applying it to diverse combustor design test cases. There the Toolbox demonstrated its capacity to achieve the required performance targets and to successfully optimise some key combustor parameters such as liner wall cooling flow and NOx emissions. In addition, the Toolbox demonstrated its ability to be applied to different types of engineering problems such as wing profile optimisation.

<p>The thermodynamic conditions for the behaviour of silicon in the lower part of the blast furnace have been the focus of the thesis. More specifically, the influences of temperature, carbon activity, total gas pressure and Fe reoxidation on silicon have been studied.</p><p>Calculations show that an increased temperature gives higher equilibrium ratio between silicon in hot metal and slag. Furthermore, laboratory reduction studies shows that the carbon activity in the cohesive zone increase with an increased reduction time. Increased carbon activity will increase the equilibrium silicon content in liquid metal.</p><p>Equilibrium calculations based on tapped hot metal and slag shows that the equilibrium silicon content of the liquid metal phase is higher than measured at tapping. Around the raceway area the equilibrium silicon content is very high. The high equilibrium silicon content makes it important to differ between the conditions under operation and the conditions of samples taken out of the blast furnace before studied. The equilibrium silicon content is strongly correlated to the CO gas partial pressure. Often this partial pressure is changed during sampling and cooling of samples. At tapping the equilibrium partial pressure of CO has been calculated to higher values than the total gas pressure inside the blast furnace.</p><p>Metal droplets found in tapped slags are probably formed by reduction of FeO. In the periphery part of the lower part of the blast furnace, it is believed that mainly FeO oxidises silicon in hot metal. It is not expected that the metal droplets in the slag is formed if FeO oxidises dissolved silicon. Instead, the iron droplets may form at reactions with gas, coke carbon or coal powder carbon. Around some droplets increased magnesium content has been found. This may be due to reactions with gaseous magnesium that, according to thermodynamic conditions, is easy to form. It has been reported that much FeO may be formed in the raceway area. The metal droplets may indicate how much FeO that reacts with other components than liquid iron. The iron found in metal droplets in the slag corresponds to between 0.02 and 0.2 wt-% FeO in the slag.</p>