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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.
221

Controle de tensão terminal e potência reativa de um grupo motor gerador diesel conectado à rede de distribuição / Terminal voltage control and reactive power of a powerplant diesel generator connected to the distribution network

Rodolpho Vilela Alves Neves 19 March 2013 (has links)
Este trabalho apresenta uma estratégia de controle coordenado para potência reativa e tensão terminal de um grupo moto gerador (GMG) para uso em um sistema de geração distribuída (GD). A partir da construção de uma superfície fuzzy, baseada no comportamento do erro e da derivada do erro de uma malha de controle, foi realizada a sintonia de controladores fuzzy PD+I para potências ativa e reativa e tensão terminal. O controlador coordenado fuzzy PD+I ajusta automaticamente a tensão nos terminais da máquina e a potência reativa fornecidas à rede de distribuição. A estratégia coordenada é dada através de um parâmetro que regula a malha de potência reativa a partir do erro de tensão terminal, priorizando o ajuste da tensão e ponderando a malha de controle de potência reativa. Para avaliar o desempenho do sistema de controle, a GD é conectada a uma rede de distribuição e submetida a eventos como entrada e saída de cargas locais. O conjunto de cargas locais é composto por um motor de indução, uma carga RLC e um retificador trifásico não controlado. Sete cenários foram simulados para avaliar a estratégia de controle em diferentes regimes de operação do GMG. Resultados para tensão terminal, fator de potência e fluxo de potências entre o sistema, as cargas e a rede, ilustram a eficiência da estratégia de controle apresentada. A estratégia de controle coordenado para potência reativa e tensão terminal se mostrou capaz de melhorar os índices de fator de potência controlando o fluxo de potência do barramento em que a GD estava conectada, sem prejudicar a tensão terminal do gerador, mantendo a GD em limites seguros de operação. / This work presents a coordinated control strategy to terminal voltage and reactive power for a diesel generation set used as a distributed gerenation system (DG). From desired control actions, a fuzzy surface was designed for fuzzy PD+I controllers. Fuzzy PD+I controllers automatically adjust the terminal voltage and the reactive power delivered to the grid. The coordinated control strategy weighs the control action for the reactive power through a variable parameter, prioritizing the terminal voltage adjustment. To illustrate the system control performance, the DG is connected to a grid dynamic model and the system is subjected to connection and disconnection of loads at the local bus. The local loads set was composed of an induction machine, a RLC load and an uncontrolled three-phase rectifier. Seven scenarios were simulated to evaluate the control strategy in different DG regime of operation. Results for terminal voltage, power factor and reactive power among the DG, the local loads and the grid, illustrates the control strategy efficiency improved the power factor by regulating the reactive power injected at the bus, maintaining the DG terminal voltage in safe operation limits.
222

Méta-modèles réduits et séparés du comportement de balayage d'un moteur Diesel 2-temps pour l'exploration évolutionnaire des espaces de solutions / Reduced and separated meta-models of the scavenging by ports in 2-stroke Diesel engines to use evolutionary algorithms in search space

Cagin, Stéphanie 09 December 2015 (has links)
L’utilisation de techniques numériques lors de la conception d’un produit s’est largement généralisée au cours des 30 dernières années. Pourtant, la lenteur des calculs et la spécialisation des modèles numériques restent problématiques.Nous avons donc choisi de développer des modèles réduits du comportement de balayage sur un moteur Diesel 2-temps à lumières. Ces modèles sont analytiques, génériques, rapides d’utilisation et permettent d’éliminer les problématiques de traitement numérique. Ils sont aussi des instruments performants dans la recherche de solutions de conception. Une modélisation CFD 2D a tout d’abord été développée pour servir de bases de données, avec la définition des paramètres primordiaux à suivre pour quantifier un balayage optimal.Le travail de recherche a dévoilé une méthodologie nouvelle fondée sur un méta-modèle du comportement dit « neuro-séparé » comprenant un modèle neuronal d’état, un modèle neuronal pseudo-dynamique et un modèle à variables séparées. Ensuite, un processus d'aide à la décision exploitant les modèles précédents a été mis en place au travers d’un processus d’optimisation évolutionnaire (fondé sur les algorithmes génétiques) puis de la simulation comportementale rapide des solutions optimales de conception par un krigeage.La démarche de conception multipoints de vue, multi-critères et multi-physiques appliquée au moteur intègre aussi une dimension cognitive : l’exploration évolutionnaire des espaces de solutions a été menée de façon libre et forcée. Afin de valider notre approche, nous avons mis en place des critères de qualification appliqués à chacun de nos modèles, permettant de quantifier les écarts visà-vis de la base initiale CFD qui a fondé nos modèles réduits.Notre démarche a mené à la création d’un outil d’aide à la modélisation et à la décision exploitant les modules Python et Matlab développés. / The use of numerical methods to design a product became more and more commonover the past 30 years. However, numerical models are still specialized and they do not run fastwhich make their use problematic. So some reduced models of scavenging have been developed. These models are analytical andgeneric; they run quickly and avoid the numerical treatment problems. They are also some efficienttools in the search of design solutions.The work carried out has led to a new methodology based on a behavioral meta-model called“neuro-separated” including a neuronal model of state, a pseudo-dynamic neuronal model and amodel with separated variables. Then, a process of decision aids exploiting the models previouslydeveloped in evolutionary algorithms (genetic algorithms) and the fast behavioral simulation of theoptimal design solutions thanks to the kriging approach.This design approach is multi-viewpoints, multi-criteria and multi-physics. It also includes acognitive dimension: both free and controlled evolutionary explorations of solution spaces have beendone. To validate the method, some qualification criteria have been evaluated for each model. Theyallow to understand and to assume the gap between the reduced models and the initial CFD base(where the model are coming from). Our approach has led to the development of a tool of model and decision aids using Python and Matlab software programs.
223

Electric Discharge Plasma Promoted Adsorption/Catalysis, For Removal Of NOx, HC And CO From An Actual Diesel Engine Exhaust

Srinivasan, A D 08 1900 (has links) (PDF)
No description available.
224

Dielectric Barrier Discharge Initiated NOx Abatement In Diesel Engine Exhaust : Towards Achieving Higher Removal Efficiency

Mohapatro, Sankarsan 07 1900 (has links) (PDF)
In the last few decades India has advanced socioeconomically due to the rapid growth of industries and automobile sector. This in turn increases the use of fossil fuel and diesel. The atmosphere gets polluted due to the harmful substances, which comes from the burning of fuel. These pollutants can be in the form of gaseous, liquid or solid particulate. Diesel engines, the major source of power in industries and automobiles, play a significant part in causing air pollution. The major pollutants in diesel exhaust are oxides of nitrogen (NOX), sulphur dioxide (SO2), carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), volatile organic compounds (VOC), aldehydes and alcohols. Due to the heavy consumption of diesel as a fuel there is an urgent need to control diesel exhaust. Diesel exhaust is a complex mixture of several gases and fine particles (commonly known as soot) that contains more than 40 toxic air contaminants. Amongst the gaseous pollutants in diesel exhaust, the major concern and a challenging task is to control oxides of nitrogen, commonly referred to as NOX as it is the major contributor for acid rain, photochemical smog etc. Successful control of emissions from diesel engines is yet to be achieved. The conventional techniques which are available to control emission now are either difficult to operate or does not satisfy the stringent emission standards. This has made the researchers throughout the world to find an alternative and effective non-conventional after treatment technique to reduce diesel engine emission. The failure of conventional techniques lead to the development of non-conventional techniques such as high voltage electric discharge based plasma which has already been proved to be economical and highly efficient in industrial electrostatic precipitators. Electric discharge plasma or non-thermal plasma produce energetic electrons which react with background molecules in flue gas leading to active species such as radicals. These radicals being chemically active selectively react with the harmful pollutants facilitating their removal/reduction. The present thesis work is an attempt to provide a technical solution to achieve higher removal efficiencies of oxides of nitrogen in the backdrop of shortcomings that exist in conventional technologies to do so. The current thesis describes the research in four stages: (i) studies on NOX removal from diesel exhaust by cross-flow DBD reactor, where design and fabrication of cross-flow DBD reactor, exhaust treatment using cross-flow DBD reactor and exhaust treatment with cascaded plasma-adsorbent technique is described (ii) studies on NOX removal from diesel exhaust by compact discharge plasma sources, where design and fabrication of high frequency high voltage AC (HVAC) using old television flyback transformer, Design and fabrication of high voltage pulse (HVPulse) using automobile ignition coil, exhaust treatment with both HVPulse and HVAC and exhaust treatment with cascaded plasma-adsorbent technique is described (iii) studies on NOX removal from diesel exhaust using solar powered discharge plasma source is described (iv) studies on the NOX removal from diesel exhaust using red mud, where exhaust treatment with red mud and Exhaust treatment cascaded plasma-red mud is covered. The results have been discussed in light of enhancing the NOX removal efficiency for stationary and automobile engine exhausts.
225

Silikonový tlumič torzních kmitů šestiválcového vznětového motoru / Silicone torsional vibration damper for a six-cylinder diesel engine

Kovář, Lukáš January 2017 (has links)
The aim of this thesis is to design crankshaft for in-line six-cylinder diesel engine and to design viscous torsional vibration damper for the cranktrain of specified parameters. The thesis includes the creation of a dynamic torsional model of cranktrain and calculation of forced vibrations of mechanism with and without damper. Part of this thesis is also strength analysis of the designed crankshaft with damper using the Finite Element Method (FEM).
226

Návrh a posouzení alternativ přeplňování vznětového motoru s recirkulací / Proposal and Examination of Supercharging Alternatives of CI-engine with Recirculation

Prášek, Ondřej January 2008 (has links)
The object of this thesis was Proposal and Examination of Supercharging Alternatives of CI-engine with Exhaust Gas Recirculation according required engine power parameters. This goal was meet by use of Turbocharger with Variable Nozzles and Air-Air intercooler.
227

Modální vlastnosti klikového ústrojí šestiválcového traktorového motoru / Modal Properties of 6-cylinder Tractor Engine Powertrain

Poláček, Milan January 2011 (has links)
Tato diplomová práce uvádí dynamiku klikového mechanismu šestiválcového řadového motoru za účelem návrhu klikového hřídele v CAD programu Pro/Engineer. Následuje popis vibrací klikového mechanismu a analytický výpočet jeho torzních vibrací. Hlavní část diplomové práce se pak zabývá konverzí hřídele do konečno-prvkového modelu v programu ANSYS a jeho importem do prostředí Adams/Engine. V tom je provedena modální analýza klikového ústrojí pro získání vlastních frekvencí a tvarů. Na konec práce je porovnán výstup z analytického řešení a výsledky z multi-body systému.
228

Vývoj těsnících zátek pro testování vysokocyklové únavové pevnosti tlakového zásobníku paliva systému Common-Rail / Seal Plugs Design for Common-Rail System Pressure Reservoir High-Cyclic Fatigue Testing

Skrutek, Ivo January 2011 (has links)
Tato diplomová práce je zaměřena na řešení problému praskání těsnících kuželů na tělesech railů při zkoušce dlouhodobé životnosti pomocí pulzního vysokotlakého testu. Hlavní částí je analýza vlivu těsnících zátek na namáhání těsnícího kuželu s následným návrhem nové zátky, která bude tvořit stejné nebo podobné zatížení všech komponent při pulzním testu jako vysokotlaká trubka, která se používá v sériové produkci. Další částí je ověření vlastností nové zátky pomocí vysokotlakého pulzního testu.
229

Konstrukce vznětového leteckého jednoválcového motoru s protiběžnými písty / Design of Diesel Aircraft Engine One-cylinder Engine with Contra Rotating Pistons

Svoboda, Tomáš January 2013 (has links)
Diploma thesis deals with design of crankshaft for two stroke opposed piston diesel engine. In the theoretical research part a history, comparison with competitive engines in nowadays light aircrafts and the advantages of opposed piston engines are mentioned. In the practical part the balancing is chosen and CAD model of crankshaft is designed. Geometry of this model is than checked for fatigue damage fallout. In the final part was chosen the propeller and appropriate reduction gearbox.
230

Injector Waveform Monitoring of a Diesel Engine in Real-Time on a Hardware in the Loop Bench

Farooqi, Quazi Mohammed Rushaed 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents the development, experimentation and validation of a reliable and robust system to monitor the injector pulse generated by an Engine Control Module (ECM) and send the corresponding fueling quantity to the real-time computer in a closed loop Hardware In the Loop (HIL) bench. The system can be easily calibrated for different engine platforms as well. The fueling quantity that is being injected by the injectors is a crucial variable to run closed loop HIL simulation to carry out the performance testing of engine, aftertreatment and other components of the vehicle. This research utilized Field Programmable Gate Arrays (FPGA) and Direct Memory Access (DMA) transfer capability offered by National Instruments (NI) Compact Reconfigurable Input-Output (cRIO) to achieve high speed data acquisition and delivery. The research was conducted in three stages. The first stage was to develop the HIL bench for the research. The second stage was to determine the performance of the system with different threshold methods and different sampling speeds necessary to satisfy the required accuracy of the fueling quantity being monitored. The third stage was to study the error and its variability involved in the injected fueling quantity from pulse to pulse, from injector to injector, between real injector stators and cheaper inductor load cells emulating the injectors, over different operating conditions with full factorial design of experimentation and mixed model Analysis Of Variance (ANOVA). Different thresholds were experimented to find out the best thresholds, the Start of Injection (SOI) threshold and the End of Injection (EOI) threshold that captured the injector “ontime” with best reliability and accuracy. Experimentation has been carried out at various data acquisition rates to find out the optimum speed of data sampling rate, trading off the accuracy of fueling quantity. The experimentation found out the expected error with a system with cheaper solution as well, so that, if a test application is not sensitive to error in fueling quantity, a cheaper solution with lower sampling rate and inductors as load cells can be used. The statistical analysis was carried out at highest available sampling rate on both injectors and inductors with the best threshold method found in previous studies. The result clearly shows the factors that affect the error and the variability in the standard deviations in error; it also shows the relation with the fixed and random factors. The real-time application developed for the HIL bench is capable of monitoring the injector waveform, using any fueling ontime table corresponding to the platform being tested, and delivering the fueling quantity in real-time. The test bench made for this research is also capable of studying injectors of different types with the automated test sequence, without occupying the resource of fully capable closed loop test benches for testing the ECM unctionality.

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