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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Application of Modular Uncertainty Techniques to Engineering Systems

Long, William C 04 May 2018 (has links)
Uncertainty analysis is crucial to any thorough analysis of an engineering system. Traditional uncertainty analysis can be a tedious task involving numerous steps that can be error prone if conducted by hand. If conducted with the aid of a computer, these tasks can be computationally expensive. In either case, the process is quite rigid. If a parameter of the system is modified or the system configuration is changed, the entire uncertainty analysis process must be conducted again giving more opportunities for calculation errors or computation time. Modular uncertainty analysis provides a method to overcome all these obstacles of traditional uncertainty analysis. The modular technique is well suited for computation by a computer which makes the process somewhat automatic after the initial setup and computation errors are reduced. The modular technique implements matrix operations to conduct the analysis. This in turns makes the process more efficient than traditional methods because computers are well suited for matrix operations. Since the modular technique implements matrix operations, the method is adaptable to system parameter or configuration modifications. The modular technique also lends itself to quickly calculating other uncertainty analysis parameters such as the uncertainty magnification factor, and the uncertainty percent contribution. This dissertation will focuson the modular technique, the extension of the technique in the form the uncertainty magnification factor and uncertainty percent contribution, and the application of the modular technique to different type of energy systems. The modular technique is applied to an internal combustion engine with a bottoming organic Rankine cycle system, a combined heat and power system, and a heating, ventilation, and air conditioning system. The results show that the modular technique is well suited to evaluate complex engineering systems. The modular technique is also shown to perform well when system parameters or configurations are modified.
132

Experimental Investigation of Octane Requirement Relaxation in a Turbocharged Spark-Ignition Engine

Baranski, Jacob A. 30 August 2013 (has links)
No description available.
133

An Improved Model-Based Methodology for Calibration of an Alternative Fueled Engine

Everett, Ryan Vincent 15 December 2011 (has links)
No description available.
134

En jämförelsestudie av fritidsbåtar mellan The Candela Seven och AMT 230 GP / A comparative study of leisure boats between the Candela Seven and AMT 230 GP

Pulat, Arpat, Zaierding, Tayierjiang January 2021 (has links)
Detta examensarbete går ut på att utföra en analys i form av en jämförelsestudie av två fritidsbåtar med funktions, ekonomisk samt hållbarhetsaspekter i fokus. Projektet utgår samt är inriktad på en eldrivenbärplansbåt The Candela Seven från elmotorbåtsproducent Candela Speed Boat AB där båten jämförs med motorbåten AMT 230 GP från Advanced Marine Tech Premium Boats och utvärderas dels med hjälp av Havsmiljöinstitutets samarbete mellan olika institutioner i Sverige som referensram. Projektmålen är att genom analys och utvärderingar av jämförelsearbete utse båten som ska prioriteras mellan Candela Seven och AMT 230 GP samt komma med eventuella rekommendationer ur funktions-, ekonomiska samt hållbarhetsperspektiv. Arbetet startade med en nulägesanalys för att skapa insikt i produktfunktionalitet av båtarna, vilka ekonomisk och hållbarhetsfördelar produkten har samt hur marknaden ser ut för elbåtar med kundbehov i fokus. För vidareanalys av insamlade data och fakta för jämförelsearbete genomfördes SWOT- och kvantitativa analysmetoder samt genom matematiska resonemang och analyser identifiera båtens egenskaper och fördelar jämfört med konkurrenten. I jämförelseanalys används jämförelsematris för värdering och sammanställning av olika parametrar mot varandra samt utse båten som ska prioriteras. I jämförelseanalysen med olika parametrar visades Candela Seven är en gynnsammare båt att välja eller köpa och som prioriteras i jämförelse med AMT 230 GP. Fokus kan bli att hitta flera kunder som är intressanta, eller produktanpassa för att uppfylla kunders önskemål. Nulägesanalys genomfördes som visar att en huvudkonkurrent med bensindriven båt identifierades samt är ett substitut som utmanar produkten. Utmärkta egenskaper från SWOT och Kvantitativa-analysen är att Candela Seven är energisparande samt lönsammare att driva med mindre underhåll jämfört med AMT 230 GP. Dessutom är produkten miljövänligare i körning med hållbarhetstänkande egenskaper och design. / This thesis is based on performing an analysis in the form of a comparative study of two leisure boats with functional, economic and sustainability aspects in focus. The project is based and focuses on an electric hydrofoil boat The Candela Seven from electric motorboat manufacturer Candela Speed Boat AB where the boat is compared with the motorboat AMT 230 GP from Advanced Marine Tech Premium Boats and evaluatedpartly with the help of the Institute of Marine Environment's cooperation betweendifferent institutions in Sweden as a reference framework. The project goals are to, through analysis and evaluations of comparative work,designate the boat that will be prioritized between Candela Seven and AMT 230 GP andgive eventual recommendations from a functional, financial and sustainabilityperspective. The work started with a current situation analysis to create insight into the productfunctionality of the boats, what economic and sustainability benefits the product hasand what the market looks like for electric boats with customer needs in focus. Forfurther analysis of collected data and facts for comparative work, SWOT andquantitative analysis methods were performed and through mathematical reasoning andanalyzes to identify the boat's properties and advantages compared to the competitor. In comparison analysis, a comparison matrix is used for valuation and compilation ofdifferent parameters against each other and to designate the boat to be prioritized.In the comparison analysis with various parameters, Candela Seven was shown to be amore favorable boat to choose or buy and which is prioritized in comparison with theAMT 230 GP. The focus can be on finding more customers that are interesting, orproduct adaptation to fulfill customer needs. The current situation analysis was carried out which shows that a main competitor witha petrol-powered boat was identified and is a substitute that challenges the product.Excellent features from the SWOT and Quantitative analysis are that Candela Seven isenergy-saving and more profitable to operate with less maintenance cost compared to the AMT 230 GP. In addition, the product is more environmentally proficient whendriving with sustainability-thinking properties and design.
135

A Wireless Sensor for Fault Detection and Diagnosis of Internal Combustion Engines

Hodgins, Sean 11 1900 (has links)
A number of non-invasive fault detection and diagnosis (FDD) techniques have been researched and have proven to have worked well in classifying faults in internal combustion engines (ICE) and other mechanical and electrical systems. These techniques are an integral step to creating more robust and accurate methods of determining where or how a fault has or will occur in such systems. These FDD techniques have the potential to not only save time avoiding a tear-down of a costly machine, but could potentially add another layer of safety in detecting and diagnosing a fault much earlier than was possible before. Looking at the previous research methods and the systems they used to acquire this data, it is a natural progression to try and make a system which is able to encapsulate all of these ideologies into one inexpensive module capable of integrating itself into the advanced set of FDD. This thesis follows along with the development of a new wireless sensor that is developed specifically for the use in FDD for ICE and other mechanical systems. A new set of software and firmware is created for the system to be able to be incorporated into previously designed algorithms. After creating and manufacturing the sensor it is put to the test by incorporating it into several Artificial Neural Networks (ANN) and comparing the results to previous experiments done with previous research equipment. Using vibration data acquired from a running engine to train a neural network, the wireless sensor was able to perform equally as well as its expensive counter parts. It proved to have the ability to achieve 100% accuracy in classifying specific engine faults. The performance of three ANN training algorithms, Levenberg-Marquardt (LM), extended Kalman Filter (EKF), and Smooth Variable Structure filter (SVSF), were tested and compared. Adding to the feasibility of a standalone system the wireless sensor was tested in a live environment as a method of instant ICE fault detection. / Thesis / Master of Applied Science (MASc)
136

Cyclic variation in the flow field behaviour within a direct injection spark ignition engine : a high speed digital particle image velocimetry study

Justham, Timothy January 2010 (has links)
Currently environmental concerns are driving internal combustion engine manufacturers to seek greater fuel efficiency, more refinement and lower emissions. Cyclic variation is a known obstacle to achieving the greatest potential against these goals and therefore an understanding of how to reduce these is sought. It is widely accepted that cyclic variation in in-cylinder flow motions is a key contributor to overall cyclic variation and therefore the characterisation of factors affecting these is an important step in the process of achieving a better understanding and ultimately control of cyclic variation. This thesis reports the development of a novel optical engine research facility in which high speed digital particle image velocimetry (HSDPIV) has been applied to the study of flow field behaviour within a direct injection spark ignition (DISI) engine. This study investigates the spatial and temporal development of flow structures over and within many engine cycles. Flow field PIV measurements have been captured with a high spatial resolution and temporal frequencies up to 5 kHz from a number of measurement locations at a large range of crank angles. The major contributions from this work have included the use of the novel measurement technique to investigate spatial and temporal flow field development in the intake runner, valve jet, in-cylinder tumble and swirl planes and the pent roof. The gathered data have been used to investigate cycle by cycle variations in both high and low frequency flow structures. Major findings of this work have included the observation of highly varying flow fields throughout the engine cycle. Frequency analysis of these flows has allowed the low frequency bulk motions and higher frequency turbulent components to be studied. The low frequency flow field components are shown to create varying flow field interactions within the cylinder that also affect the manner in which the flow develops over the course of the cycle. The intensity of the turbulence fluctuations, u , has been calculated based upon the high frequency components within the flow and variations within this are shown to correlate with pressure related combustion parameters.
137

Caractérisation expérimentale d’une turbine de suralimentation automobile et modélisation de ses courbes caractéristiques de fonctionnement / Experimental characterization of an automotive turbocharger turbine and modeling of its performance maps

Salameh, Georges 07 December 2016 (has links)
La diminution de la cylindrée ou le downsizing du moteur est potentiellement l'une des stratégies les plus efficaces pour améliorer la consommation de carburant et diminuer les émissions polluantes. Dans le domaine de la suralimentation, la simulation est limitée par les caractéristiques de fonctionnement des turbines fournies par les constructeurs. Une extrapolation précise et fiable des cartographies turbine est donc l’objectif de cette thèse. Une étude expérimentale sur une turbine radiale d’un turbocompresseur est effectuée avec différentes techniques pour mesurer la cartographie turbine la plus large possible. Les mesures sont effectuées sur un banc turbocompresseur classique avec différentes températures d'entrée turbine. Puis une technique de gavage en entrée et en sortie compresseur est testée. Le compresseur est ensuite remplacé par un autre compresseur à roue inversée qui peut aider la turbine à tourner et même l’entrainer. Les débits les plus faibles et même les débits négatifs sont mesurés. Un banc turbine électromécanique a également été développé, mais n’a pas pu donner de résultats satisfaisants à cause de problèmes techniques mais des évolutions à venir restent prometteuses. Les diverses techniques expérimentales testées ont aussi permis de mesurer le rendement isentropique de la turbine et le rendement mécanique du turbocompresseur. Finalement, plusieurs modèles d’extrapolation des courbes caractéristiques turbine ont été testés et confrontés aux résultats expérimentaux. / Engine downsizing is potentially one of the most effective strategies being explored to improve fuel economy and reduce emissions. In the field of turbocharging,simulation is limited by the operating characteristics of turbines supplied by the manufacturers. An accurate and precise extrapolation of the turbine performance maps is the main aim of this study. An experimental study was done on a radial turbine of a turbocharger with different techniques to measure the wider turbine performance map possible. Measurements were done on a classic turbocharger test bench with different turbine inlet temperatures. Then air was blown to the compressor inlet and exit: it is the compressor “gavage”. The compressor is then replaced with another one with are versed rotor: this compressor can help the turbine turn and even drive it itself. The lowest mass flow rates are measured even the negative ones. An electromechanical turbine test bench was developed but did not work correctly because of technical problems but future developments are promising. The various experimental techniques used allowed also the measurement of the turbine isentropic efficiency and the turbocharger mechanical efficiency. Finally, many extrapolation models of the turbine performance maps were tested and compared to the experimental results.
138

"PROCESSAMENTO, USINAGEM E DESGASTE DE LIGAS SINTERIZADAS PARA APLICAÇÕES AUTOMOTIVAS" / "OBTENTION, MACHINING AND WEAR OF SINTERED ALLOYS FOR AUTOMOTIVE APPLICATIONS"

Jesus Filho, Edson Souza de 13 March 2006 (has links)
O objetivo deste trabalho foi desenvolver potenciais materiais para aplicações automotivas, em particular como insertos para assento de válvula em motores de combustão interna à gasolina. O desenvolvimento compreendeu as etapas de processamento dos materiais via metalurgia do pó, tratamento térmico, caracterização microestrutural e mecânica, usinagem e desgaste dos mesmos. O desenvolvimento objetivou principalmente a redução de custo e a aplicação de elementos menos poluentes, excluindo-se, por exemplo, a aplicação do Co devido ao seu alto custo e do Pb devido aos seus efeitos toxicológicos e prejudiciais ao meio ambiente. A realização de uma pesquisa minuciosa na busca de patentes relacionadas indicou que os materiais estudados apresentam composições particulares, e, portanto inéditas. Os resultados encontrados nos ensaios de dureza e de resistência à compressão radial nas amostras tratadas termicamente apresentaram resultados superiores aos da liga comercial atualmente em uso. Testes de usinabilidade em amostras sem tratamento térmico apresentaram comportamento similar ao da liga comercial, indicando que a usinabilidade do material praticamente não foi afetada com a mudança na composição química. Após a etapa de tratamento térmico, as ligas obtidas apresentaram valores de esforços de corte superiores aos do material comercial. Os resultados dos testes de desgaste abrasivo em amostras tratadas termicamente apresentaram menores valores de coeficientes de atrito e perda de massa em todos os casos em relação ao material comercial. Este comportamento é devido aos benefícios introduzidos pelo tratamento térmico executado e pela adição de alguns elementos resistentes ao desgaste na forma de carbonetos de Nb e Ti/W. Os resultados dos esforços de corte apresentaram boa concordância com os resultados dos ensaios de desgaste. Os materiais produzidos apresentam-se como potenciais candidatos para substituir, com vantagens, inserto para assento de válvula a base de Fe-Co em motores de combustão interna a gasolina. / The aim of this work was the development of materials for automotive applications, in particular, valve seat inserts for gasoline combustion engines. The development involved the following activities: processing by powder metallurgy techniques, heat treatment, mechanical and microstructural characterization, machining and wear of materials. This work was undertaken aiming cost reduction of this component by the use of cheaper and less pollutant elements, eliminating the presence of Co and Pb due to their high cost and toxicological effects, respectively. The accomplishment of a thorough research into patents revealed that the materials studied here present particular compositions and were not yet produced. The results of hardness measurements and the transverse radial strength of the studied materials, after heat treatment, revealed superior properties than the commercial alloys applied at the moment. The machining tests of the material without heat treatment indicated a similar behaviour in comparison to the commercial alloy, suggesting that the new alloy chemistry composition was not deleterious in this sense. After heat treatment, the obtained alloys presented a cutting force increase in relation to the commercial alloy. Wear tests results of heat treated materials presented smaller friction coefficient and mass loss than the commercial alloy, in all cases. This was especially achieved due to the advantages offered by heat treatment allied to the addition of NbC and Ti/W carbides. The materials obtained here showed to be potential candidates to substitute with advantages, valve seat inserts made of Fe-Co alloys for gasoline combustion engines.
139

Desenvolvimento de um gerenciador eletrônico para motores tricombustível. / Development of an electronic controller for tri-fuel engines.

Veiga, Michel Robert 10 September 2010 (has links)
O objetivo do desenvolvimento do projeto foi minimizar uma das principais desvantagens no uso do gás natural veicular, que é a perda de potência, e aumentar sua eficiência volumétrica através da construção de um circuito eletrônico capaz de gerenciar de forma eficiente a injeção do gás. O aumento do rendimento é obtido através do gerenciamento eficiente da mistura ar-combustível utilizando um sistema de malha fechada. O gerenciamento da relação de potência e economia é conseguido com o uso simultâneo de gás natural e o combustível líquido. Nos sistemas de conversão atuais e nos veículos originais a gás natural, a perda de potência é compensada desligando o sistema de gás e utilizando somente o combustível líquido, sendo esta seleção feita de forma manual na maioria dos sistemas de conversão e de forma automática no Fiat Siena tetrafuel, não possibilitando o uso simultâneo do gás com o combustível líquido. A exigência de potência é medida através do ângulo do pedal do acelerador. Quando a exigência de potência é baixa, o sistema opera apenas com gás. No momento em que há solicitação de potência intermediária, o sistema opera com diferentes proporções de etanol e gás. Na situação de solicitação de potência máxima, é utilizado apenas o combustível líquido. Foram feitas comparações entre o sistema convencional e o sistema proposto, através de ensaios dinamométricos, rodoviários e emissão de poluentes. O veículo Volkswagen Gol com seu sistema original utilizando somente etanol possui potência máxima de 64,06 cavalos, (47,77 Kilowatts) e consumo de 12,6 quilômetros por litro de etanol. Com o sistema convencional de gás natural aspirado, o consumo foi de 21 quilômetros por metro cúbico e a potência não ultrapassou 51,82 cavalos (38,64 Kilowatts), com o protótipo desenvolvido a eficiência volumétrica aumentou 25% com consumo de 26,4 quilômetros por metro cúbico. O gerenciamento de potência proporciona potências intermediárias acima de 51,82 cavalos (38,64 Kilowatts), até a potência máxima de 64,06 cavalos (47,77 Kilowatts) em situações que uma maior potência é requerida. O sistema desenvolvido proporciona o benefício da flexibilidade no abastecimento disponível nos sistemas atuais, com a flexibilidade na potência não disponível nos sistemas atuais. / This project intended to minimize one of the main disadvantages of using natural gas vehicles, which was the loss of power, and increase their volumetric efficiency by building an electronic circuit able to efficiently manage the gas injection. The increase in volumetric efficiency is obtained through the efficient management of air-fuel mixture using a closed loop system. The management of the power and economy ratio is achieved with the simultaneous use of natural gas and liquid fuel. In the current conversion systems and original vehicles that use natural gas, the power loss is compensated by turning off the gas system and using only the liquid fuel. This selection is done manually in most conversion systems, and automatically at Fiat Siena Tetrafuel, not allowing the simultaneous use of gas to liquid fuel. The demand for power is measured by the angle of the accelerator pedal. When the power demand is low, the system operates only with natural gas. When intermediate power is required, the system operates with different proportions of ethanol and natural gas. For maximum power, only ethanol is used. Comparisons were made between the conventional and the proposed system through dynamometer tests, road tests and emission analyses. The Volkswagen Gol with original system using only ethanol has a maximum power of 64.06 horses (47.77 Kilowatts) and consumption of 12.6 kilometers per liter of ethanol. With conventional aspirated natural gas system, the consumption was 21 km per cubic meter and the power did not exceed 51.82 horses (38.64 Kilowatts). With the prototype, volumetric efficiency increases by 25%, with consumption of 26.4 kilometers per cubic meter. The power management provides intermediate powers up to 51.82 horses (38.64 Kilowatts) until the maximum power of 64.06 horses (47.77 Kilowatts) in situations where more power is required. The developed system provides the benefit of refueling flexibility found in the original system, with power flexibility not available in original systems.
140

Desenvolvimento de um gerenciador eletrônico para motores tricombustível. / Development of an electronic controller for tri-fuel engines.

Michel Robert Veiga 10 September 2010 (has links)
O objetivo do desenvolvimento do projeto foi minimizar uma das principais desvantagens no uso do gás natural veicular, que é a perda de potência, e aumentar sua eficiência volumétrica através da construção de um circuito eletrônico capaz de gerenciar de forma eficiente a injeção do gás. O aumento do rendimento é obtido através do gerenciamento eficiente da mistura ar-combustível utilizando um sistema de malha fechada. O gerenciamento da relação de potência e economia é conseguido com o uso simultâneo de gás natural e o combustível líquido. Nos sistemas de conversão atuais e nos veículos originais a gás natural, a perda de potência é compensada desligando o sistema de gás e utilizando somente o combustível líquido, sendo esta seleção feita de forma manual na maioria dos sistemas de conversão e de forma automática no Fiat Siena tetrafuel, não possibilitando o uso simultâneo do gás com o combustível líquido. A exigência de potência é medida através do ângulo do pedal do acelerador. Quando a exigência de potência é baixa, o sistema opera apenas com gás. No momento em que há solicitação de potência intermediária, o sistema opera com diferentes proporções de etanol e gás. Na situação de solicitação de potência máxima, é utilizado apenas o combustível líquido. Foram feitas comparações entre o sistema convencional e o sistema proposto, através de ensaios dinamométricos, rodoviários e emissão de poluentes. O veículo Volkswagen Gol com seu sistema original utilizando somente etanol possui potência máxima de 64,06 cavalos, (47,77 Kilowatts) e consumo de 12,6 quilômetros por litro de etanol. Com o sistema convencional de gás natural aspirado, o consumo foi de 21 quilômetros por metro cúbico e a potência não ultrapassou 51,82 cavalos (38,64 Kilowatts), com o protótipo desenvolvido a eficiência volumétrica aumentou 25% com consumo de 26,4 quilômetros por metro cúbico. O gerenciamento de potência proporciona potências intermediárias acima de 51,82 cavalos (38,64 Kilowatts), até a potência máxima de 64,06 cavalos (47,77 Kilowatts) em situações que uma maior potência é requerida. O sistema desenvolvido proporciona o benefício da flexibilidade no abastecimento disponível nos sistemas atuais, com a flexibilidade na potência não disponível nos sistemas atuais. / This project intended to minimize one of the main disadvantages of using natural gas vehicles, which was the loss of power, and increase their volumetric efficiency by building an electronic circuit able to efficiently manage the gas injection. The increase in volumetric efficiency is obtained through the efficient management of air-fuel mixture using a closed loop system. The management of the power and economy ratio is achieved with the simultaneous use of natural gas and liquid fuel. In the current conversion systems and original vehicles that use natural gas, the power loss is compensated by turning off the gas system and using only the liquid fuel. This selection is done manually in most conversion systems, and automatically at Fiat Siena Tetrafuel, not allowing the simultaneous use of gas to liquid fuel. The demand for power is measured by the angle of the accelerator pedal. When the power demand is low, the system operates only with natural gas. When intermediate power is required, the system operates with different proportions of ethanol and natural gas. For maximum power, only ethanol is used. Comparisons were made between the conventional and the proposed system through dynamometer tests, road tests and emission analyses. The Volkswagen Gol with original system using only ethanol has a maximum power of 64.06 horses (47.77 Kilowatts) and consumption of 12.6 kilometers per liter of ethanol. With conventional aspirated natural gas system, the consumption was 21 km per cubic meter and the power did not exceed 51.82 horses (38.64 Kilowatts). With the prototype, volumetric efficiency increases by 25%, with consumption of 26.4 kilometers per cubic meter. The power management provides intermediate powers up to 51.82 horses (38.64 Kilowatts) until the maximum power of 64.06 horses (47.77 Kilowatts) in situations where more power is required. The developed system provides the benefit of refueling flexibility found in the original system, with power flexibility not available in original systems.

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