Thèses sur le sujet « CNG Engines »
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Königsson, Fredrik. « On Combustion in the CNG-Diesel Dual Fuel Engine ». Doctoral thesis, KTH, Förbränningsmotorteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151188.
Texte intégralQQC 20140915
Šmerda, Ondřej. « Návrh koncepce leteckého motoru na CNG ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401574.
Texte intégralRahimi, Najmeh. « NOx reduction in a compressed natural gas (CNG) engine with humid air intake ». Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10011272.
Texte intégralOne of the major environmental challenges facing our planet and living beings is the global warming. This phenomena, known as the gradual increase in the overall temperature of earth's atmosphere is mostly caused by the greenhouse eect which is a result of increased levels of greenhouse gases. Major constitutes of these gases are Carbon Dioxide (CO2) and Nitrogen Oxides (NOx). Transportation sector is responsible for releasing a signicant portion of these gases into the atmosphere. In recent decades, many endeavors such as using alternative fuels and modications in engine cycles have been made to control the amount of pollutants emitted from internal combustion engines. In this work, the impact of adding humidity to the input Oxidizer stream on reduction of NOx and Carbone Dioxide (CO2) of a CNG engine has been studied. With the addition of the humidity, the combustion temperature will be reduced which improves the engines lifespan. Non-Premixed combustion process in a single cylinder is simulated using the STAR CCM+ software from CD-Adapco company, using the Presumed Probability Density Function (PPDF) combustion model which is an accurate model for combustion. Simulation results indicate with 10% humid air, signicant reductions in NOx and CO2 are obtained, with a moderate increase in CO output. Adding humidity results in total emission reduction.
Wojcik, Rudolf. « Sací potrubí zážehového motoru na CNG o výkonu 140kW ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-231036.
Texte intégralHillstrom, David Roger. « Light Duty Natural Gas Engine Characterization ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408967285.
Texte intégralHan, Yuwei. « Ultra-Low NOx Measurement and Emission Factors Evaluation of a Compressed Natural Gas (CNG) Heavy-Duty Engine ». Thesis, University of California, Riverside, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10194518.
Texte intégralHeavy duty on-road vehicles represent one of the largest sources of NO x emissions and fuel consumption in North America. Heavy duty vehicles are predominantly fueled with diesel, with the recent interest in natural gas (NG) systems. As emissions and greenhouse gas regulations continue to tighten new opportunities for advanced fleet specific heavy duty vehicles are becoming available with improved fuel economy. NOx emissions have dropped 90% for heavy duty vehicles with the recent 2010 certification limit. Additional NOx reductions of another 90% are desired for the South Coast Air basin to meet its 2023 NOx inventory requirements and the California optional low NOx standard in 2015.
One of the difficulties in quantifying NOx emissions at the levels proposed in this research (90% of the 2010 certification level ~ 0.02 g/bhp-hr) is the measurement methods are approaching their detection limit to sufficiently quantify NOx emissions. Three upgraded NO x measurement methods were considered which include a raw NOx measurement integrated with real time exhaust flow, a real-time ambient correction approach, and a trace level ambient analyzer for accurate bag analysis. In summary the improved methods varied in their success where the raw sampling approach showed to be the most accurate and precise over the rage of conditions tested.
The ISL G NZ 8.9 liter NG engine met and exceeded the target NO x emissions of 0.02 g/bhp-hr. This engine significantly reduced 97%–100% of NOx emissions compared with previous ISL G 8.9 engines. The NOx emissions decreased as the duty cycle was decreased which was the opposite trend for the diesel vehicles. It is expected NG vehicles could play a role in the reduction of the south coast NOx inventory problem given their near zero emission factors demonstrated.
Tenora, Tomáš. « Racionalizace výroby součásti zemědělského stroje ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318724.
Texte intégralRingenson, Josefin. « Efficiency of CNN on Heterogeneous Processing Devices ». Thesis, Linköpings universitet, Programvara och system, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-155034.
Texte intégralJelínek, Petr. « Obrobení náboje kola formulového vozu na CNC obráběcím centru ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229749.
Texte intégralMorgan, Jolvani. « TÉCNICAS DE SEGMENTAÇÃO DE IMAGENS NA GERAÇÃO DE PROGRAMAS PARA MÁQUINAS DE COMANDO NUMÉRICO ». Universidade Federal de Santa Maria, 2008. http://repositorio.ufsm.br/handle/1/8071.
Texte intégralO presente trabalho descreve uma ferramenta para extração de características em imagens 2D aplicado à automação industrial. O método implementado utiliza técnicas de segmentação de imagens em peças modelo, como detecção de bordas, na extração das coordenadas espaciais da imagem e importação em aplicativos CAD (Computer-Aided Design) para a geração de programas de Comando Numérico Computadorizado (CNC). Este trabalho consiste em copiar um determinado modelo (imagem) partindo de um objeto já existente, o que caracteriza um processo de engenharia reversa. Um protótipo inicial foi desenvolvido usando a linguagem Java com o IDE Eclipse e a biblioteca para manipulação de imagens complexas, o API Java Advanced Image (JAI). Para a aquisição das peças a serem usinadas, foi elaborado um ambiente de iluminação a fim de ressaltar áreas de interesse melhorando a luminância das mesmas e viabilizando a aplicação das técnicas desenvolvidas nesse protótipo. Diferentes operadores de detecção de bordas foram explorados, a fim de aplicar a melhor técnica e que melhor representasse a peça real. Uma nova técnica de segmentação foi adaptada ao protótipo, a partir da integração da tecnologia Java/MatLab e com a aquisição de imagens através da técnica Multi-flash. Após a aplicação de diferentes técnicas de processamento, um arquivo texto contendo as coordenadas da imagem (peça) é gerado e importado no CAD. No ambiente CAD, é executado o cálculo da trajetória da ferramenta que identifica a geometria da peça e define o caminho da ferramenta na geração do programa CNC para reprodução da mesma. Resultados apresentados e a avaliação da ferramenta demonstram a viabilidade de aplicação do sistema desenvolvido como parte automatizada para reprodução de peças em máquinas de comando numérico.
Garg, Manish. « Studies On Fuel-Air Stratification And Combustion Modelling In A CNG-Fuelled Engine ». Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2593.
Texte intégralRezapour, Kambiz, Byron A. Mason, Alastair S. Wood et Kambiz M. Ebrahimi. « Bi-fuel SI Engine Model for Analysis and Optimization ». 2014. http://hdl.handle.net/10454/10983.
Texte intégralThe natural gas as an alternative fuel has economical and environmental benefits. Bi-fuel engines powered by gasoline and compressed natural gas (CNG) are an intermediate and alternative step to dedicated CNG engines. The conversion to bi-fuel CNG engine could be a short-term solution to air pollution problem in many developing countries. In this paper a mathematical model of a bi-fuel four-stroke spark ignition (SI) engine is presented for comparative studies and analysis. It is based on the two-zone combustion model, and it has the ability to simulate turbulent combustion. The model is capable of predicting the cylinder temperature and pressure, heat transfer, brake work , brake thermal and volumetric efficiency, brake torque, brake specific fuel consumption (BSFC), brake mean effective pressure (BMEP), concentration of CO2, brake specific CO (BSCO) and brake specific NOx (BSNOx). The effect of engine speed, equivalence ratio and performance parameters using gasoline and CNG fuels are analysed. The model has been validated by experimental data using the results obtained from a bi-fuel engine. The results show the capability of the model in terms of engine performance optimization and minimization of the emissions. The engine used in this study is a typical example of a modified bi-fuel engine conversion, which could benefit the researchers in the field.
Boddez, Jason Bradley. « Evaluation of SI-HCCI-SI mode-switching using conventional actuation on a CNG engine ». Master's thesis, 2011. http://hdl.handle.net/10048/1825.
Texte intégralHUANG, TIAN-LIN, et 黃天麟. « A Multi-vendor CNC Tool Holder Search Engine with Standardized Metadata ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4pq544.
Texte intégral國立暨南國際大學
資訊管理學系
106
Searching holders manually in catalogs to make a pair of CNC holder and tool is time wasting and inefficient. As there are no standards for the parameters of holders, this searching can even ineffective in multi-vendor environment. In this thesis, we design and implement a search engine for multi-vendor tool holder based on standardized metadata. The search engine has following advantages: ・CNC tool holders can be searched with standardized data. ・Using metadata to render input view and to generate an exclusive data structure of a CNC tool holder. ・Showing original parameters’ name at input and result views to prevent confusion between the detail images of CNC tool holder and the standardized parameters. ・The scalability of metadata makes it easy to add properties for new processes without modifying code. ・Providing Web API that can be integrated to related services such as Inventory Control System or Interference Prevention System.
Lourenço, Carlos Eduardo Ribeiro. « Contribuição para o fabrico de motor de ciclo sobre-expandido ». Master's thesis, 2012. http://hdl.handle.net/1822/22676.
Texte intégralDesde o aparecimento dos primeiros motores de combustão interna, estes têm sido constantemente alvo de evoluções em função das necessidades do meio ao qual se destinam, seja a procura por melhor fiabilidade, por maiores potências ou mesmo pela otimização dos mesmos de modo a tornar o seu custo de produção mais sustentável. Atualmente existe uma crescente preocupação pelos problemas ambientais, bem como pela escassez das reservas de petróleo, o que associado à crise económico-financeira vivida torna a procura por uma maior eficiência energética dos motores de combustão interna, o principal campo de evolução dos mesmos. Neste contexto, surge o conceito de motor sobre-expandido, sendo este um tipo de motor que apresenta rendimentos superiores aos motores convencionais, permitindo deste modo registar valores de consumos e emissões de poluentes francamente inferiores aos dos motores convencionais. O presente trabalho tem como finalidade o fabrico de um motor de combustão interna, mais concretamente o UMotor. Este é um motor de ciclo sobre-expandido que vem sendo desenvolvido há já alguns anos no Departamento de Engenharia Mecânica da Universidade do Minho e que se destina a equipar o EconomicUM. O trabalho apresentado faz inicialmente um enquadramento teórico acerca dos motores de ciclo sobre-expandido, dando a conhecer a sua origem, o seu principio de funcionamento e o seu papel na sociedade atual. Posteriormente, o trabalho é focado no desenvolvimento e fabrico de alguns componentes do UMotor, tais como o cárter, a árvore de cames, os balanceiros, a cambota e o coletor de admissão. Ao longo do trabalho apresentado são dadas a conhecer as diferentes fases no desenvolvimento dos componentes, desde o projeto dos mesmos utilizando ferramentas CAD/CAM, aos processos de fabrico utilizados bem como os procedimentos a ser adotado de modo a que no futuro se concretize a realização de um protótipo funcional do motor.
Since internal combustion engines made their early appearance, continuous evolutions took place in order to fulfill the requests of their application domains, whether pursuing reliability improvement, higher engine power or even manufacturing optimization and cost sustainability. Nowadays there is a growing concern about environmental issues, including oil reserves shortage, economic and financial crisis impact, so driving critical increase of energetic efficiency in internal combustion engines, as a field of study. In this context arises the concept of over-expanded engine, for it shows higher efficiency, allowing less fuel consumption and lower polluting emissions than conventional engines. The present work describes the manufacturing constraints and solutions of an experimental internal combustion engine, the UMotor. This is an over-expanded cycle engine under development in the Department of Mechanical Engineering of University of Minho, to equip the EconomicUM, a formula Shell® prototype vehicle. A theoretical overview is presented about the over-expanded cycle engines, describing its principles of operation and their possibilities in the society. The work is focused on the development and manufacturing of components of the engine, including the crankcase, the camshaft, the rocker arms, the crankshaft and the intake manifold. The work presents an overview of the actual stage in the development of components, including modifications to the project using CAD/CAM tools, and describes the manufacturing processes and procedures to be undertaken in the near future to achieve a fully functional prototype engine.