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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.
1

Determinação do rendimento na barra de tração de tratores agrícolas com tração dianteira auxiliar (4x2 Tda)

Masiero, Fabrício Campos [UNESP] 05 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-05Bitstream added on 2014-06-13T18:52:25Z : No. of bitstreams: 1 masiero_fc_me_botfca.pdf: 638059 bytes, checksum: abfe7790012d582df70c55bce95376dd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O trator agrícola é a principal fonte de potência utilizada na agricultura e a maioria dos novos modelos disponíveis no mercado apresenta tração dianteira auxiliar (TDA). A preferência pelos tratores com tração dianteira auxiliar é devido à sua maior capacidade de tração, principalmente em condições trativas adversas e, sobretudo pela relação benefício e custo ser positiva e maior que os outros modelos. Esse trabalho foi realizado com o objetivo de avaliar o rendimento dinâmico na barra de tração de tratores agrícolas com tração dianteira auxiliar (4x2 TDA) em diferentes condições de superfície trativa comparando-os com os valores teóricos e práticos da bibliografia (“Fator 0,86” de Wendel Bowers e norma D497.4 ASAE, 1999) e determinar o rendimento dinâmico na barra para a superfície de solo com cobertura vegetal, pois existe pouca bibliografia e é uma realidade no Brasil com o plantio direto na palha. Avaliaram-se onze tratores agrícolas em diversas condições de ensaio de campo e condições de superfície, variando-se o tipo construtivo e modelos de conjunto de pneus, pressões de inflação dos pneus, relações entre o peso e potência do motor e velocidade teórica de deslocamento. Os dados de rendimento máximo na barra de tração do trator obtidos nos ensaios foram arranjados em grupos, obtendo-se o rendimento dinâmico médio na barra de tração e desvio padrão para cada condição de superfície. Foram coletados os dados para o cálculo do rendimento na barra de tração do trator, velocidade de deslocamento, patinagem das rodas dianteiras e traseiras do trator, consumo de combustível, força de tração e potência disponível na barra de tração.a realização do experimento, utilizou-se a Unidade Móvel de Ensaio... / The agricultural tractor is the main power source used in the agriculture and the most of available new tractor models in the marketing present auxiliary front drive (4WD). The preference for the 4WD tractors is due to biggest traction capacity, mainly in adverse tractive conditions and, mainly for the relationship benefit and cost to be positive and larger than the other models. This research was accomplished with the objective to evaluate the dynamic drawbar performance of several agricultural tractors 4WD in different surface condition (concrete, firm soil and tilled soil) comparing them with the theoretical and practical values of the bibliography (Wendel Bowers 0.86 Factor and D497.4 ASAE standard, 1999) and to determine the dynamic drawbar performance for the soil surface with vegetable covering, that doesn't exist in the bibliography and it is a reality in Brazil with the minimum cultivate. Eleven agricultural tractors were evaluated all 4WD in several field test conditions and surface conditions, being varied the tire constructive type and models, tire inflation pressures, relationships between the weight and engine power and forward speed. The maximum tractor drawbar performance obtained in the tests was arranged in groups, being obtained the medium dynamic drawbar... (Complete abstract click electronic access below)
2

Preliminary Turboshaft Engine Design Methodology for Rotorcraft Applications

Suhr, Stephen Andrew 20 November 2006 (has links)
In the development of modern rotorcraft vehicles, many unique challenges emerge due to the highly coupled nature of individual rotorcraft design disciplines therefore, the use of an integrated product and process development (IPPD) methodology is necessary to drive the design solution. Through the use of parallel design and analysis, this approach achieves the design synthesis of numerous product and process requirements that is essential in ultimately satisfying the customers demands. Over the past twenty years, Georgia Techs Center for Excellence in Rotorcraft Technology (CERT) has continuously focused on refining this IPPD approach within its rotorcraft design course by using the annual American Helicopter Society (AHS) Student Design Competition as the design requirement catalyst. Despite this extensive experience, however, the documentation of this preliminary rotorcraft design approach has become out of date or insufficient in addressing a modern IPPD methodology. In no design discipline is this need for updated documentation more prevalent than in propulsion system design, specifically in the area of gas turbine technology. From an academic perspective, the vast majority of current propulsion system design resources are focused on fixed-wing applications with very limited reference to the use of turboshaft engines. Additionally, most rotorcraft design resources are centered on aerodynamic considerations and largely overlook propulsion system integration. This research effort is aimed at bridging this information gap by developing a preliminary turboshaft engine design methodology that is applicable to a wide range of potential rotorcraft propulsion system design problems. The preliminary engine design process begins by defining the design space through analysis of the initial performance and mission requirements dictated in a given request for proposal (RFP). Engine cycle selection is then completed using tools such as GasTurb and the NASA Engine Performance Program (NEPP) to conduct thorough parametric and engine performance analysis. Basic engine component design considerations are highlighted to facilitate configuration trade studies and to generate more detailed engine performance and geometric data. Throughout this approach, a comprehensive engine design case study is incorporated based on a two-place, turbine training helicopter known as the Georgia Tech Generic Helicopter (GTGH). This example serves as a consistent propulsion system design reference highlighting the level of integration and detail required for each step of the preliminary turboshaft engine design methodology.
3

Determinação do rendimento na barra de tração de tratores agrícolas com tração dianteira auxiliar (4x2 Tda) /

Masiero, Fabrício Campos, 1982. January 2010 (has links)
Orientador: Kléber Pereira Lanças / Banca: Alberto Kazushi Nagaoka / Banca: Paulo Roberto Arbex Silva / Resumo: O trator agrícola é a principal fonte de potência utilizada na agricultura e a maioria dos novos modelos disponíveis no mercado apresenta tração dianteira auxiliar (TDA). A preferência pelos tratores com tração dianteira auxiliar é devido à sua maior capacidade de tração, principalmente em condições trativas adversas e, sobretudo pela relação benefício e custo ser positiva e maior que os outros modelos. Esse trabalho foi realizado com o objetivo de avaliar o rendimento dinâmico na barra de tração de tratores agrícolas com tração dianteira auxiliar (4x2 TDA) em diferentes condições de superfície trativa comparando-os com os valores teóricos e práticos da bibliografia ("Fator 0,86" de Wendel Bowers e norma D497.4 ASAE, 1999) e determinar o rendimento dinâmico na barra para a superfície de solo com cobertura vegetal, pois existe pouca bibliografia e é uma realidade no Brasil com o plantio direto na palha. Avaliaram-se onze tratores agrícolas em diversas condições de ensaio de campo e condições de superfície, variando-se o tipo construtivo e modelos de conjunto de pneus, pressões de inflação dos pneus, relações entre o peso e potência do motor e velocidade teórica de deslocamento. Os dados de rendimento máximo na barra de tração do trator obtidos nos ensaios foram arranjados em grupos, obtendo-se o rendimento dinâmico médio na barra de tração e desvio padrão para cada condição de superfície. Foram coletados os dados para o cálculo do rendimento na barra de tração do trator, velocidade de deslocamento, patinagem das rodas dianteiras e traseiras do trator, consumo de combustível, força de tração e potência disponível na barra de tração.a realização do experimento, utilizou-se a Unidade Móvel de Ensaio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The agricultural tractor is the main power source used in the agriculture and the most of available new tractor models in the marketing present auxiliary front drive (4WD). The preference for the 4WD tractors is due to biggest traction capacity, mainly in adverse tractive conditions and, mainly for the relationship benefit and cost to be positive and larger than the other models. This research was accomplished with the objective to evaluate the dynamic drawbar performance of several agricultural tractors 4WD in different surface condition (concrete, firm soil and tilled soil) comparing them with the theoretical and practical values of the bibliography (Wendel Bowers "0.86 Factor" and D497.4 ASAE standard, 1999) and to determine the dynamic drawbar performance for the soil surface with vegetable covering, that doesn't exist in the bibliography and it is a reality in Brazil with the minimum cultivate. Eleven agricultural tractors were evaluated all 4WD in several field test conditions and surface conditions, being varied the tire constructive type and models, tire inflation pressures, relationships between the weight and engine power and forward speed. The maximum tractor drawbar performance obtained in the tests was arranged in groups, being obtained the medium dynamic drawbar... (Complete abstract click electronic access below) / Mestre
4

Bewertung von alternativen Antriebskonzepten in Fahrzeugen mit unterschiedlichen Einsatzcharakteristiken / Evaluation of alternative propulsion concepts of vehicles with different characteristics

Ahmed, Mohamed 20 November 2004 (has links) (PDF)
Der weltweit steigende Mobilitätsbedarf führt in der Zukunft zur weiteren Zunahme des Primärenergiebedarfs. Die Rohstoffvorräte unserer Erde sind begrenzt. Rohstoffe, die heute verbraucht werden, stehen zukünftigen Generationen nicht mehr zur Verfügung. Die sparsame und effiziente Nutzung der Ressourcen stellt deshalb den Schlüssel zu einer nachhaltigen Entwicklung dar. Im Mittelpunkt steht dabei der Energieverbrauch. Vor allem die Industrieländer stehen vor der Herausforderung, ihren Verbrauch an begrenzten Energierohstoffen Schritt für Schritt zurückzufahren. Der Wirtschaftsbereich der Europäischen Union kann dabei eine positive Bilanz vorweisen. Eingeschlossen in diese Bilanz ist der Verkehrsbereich. Die modernen Fahrzeugflotten konnten durch die ständige Weiterentwicklung den Streckenkraftstoffverbrauch und die Abgasemissionen erheblich absenken. Eine Entwicklung, die noch nicht am Ende ist. Trotz dieser positiven Tendenz gerät die globale Bilanz durch eine dramatische Zunahme der Fahrzeugflotten, besonders in den Entwicklungsländern, kontinuierlich in eine Schieflage. Die Energieverbräuche steigen und die Ressourcen der Energieträger Öl, Gas und Kohle nehmen ab. Es ist bekannt, dass weltweit besonders in hochentwickelten Industrieländern dieser Entwicklung durch Alternativ-Konzepte entgegengesteuert wird. Im Verkehrsbereich sind dies unter anderem veränderte Fahrzeugkonzepte (z. B. Hybridfahrzeuge) sowie die mittel- und längerfristige Substitution der konventionellen, mineralölstämmigen Kraftstoffe durch Erdgaskraftstoffe (SynFuel, nach der Shell-Mittel-Destillat-Synthese, SMDS, hergestellt) oder Kraftstoffe (Sun Fuel) aus regenerativen Energieträgern wie Restholz, Energiepflanzen oder Biomüll. Diese Entwicklungen werden durch eine permanente Reduzierung der Abgasemissionen von verbrennungsmotorisch angetriebenen Fahrzeugen begleitet. Insbesondere sind dies einerseits die limitierten Schadstoffe, welche in den einzelnen Ländern gesetzlich verankert sind, und andererseits die CO2-Emission, die z. B. noch auf einer freiwilligen Selbstverpflichtung der Automobilindustrie (in Deutschland 140 g/km CO2 – Ausstoß) basieren. Kapitel 1: Einführung 2 Alle diese Entwicklungen gilt es im Voraus abzuschätzen bzw. mit fundierten Betrachtungen in den Entwicklungsprozess einzuordnen. Dies gilt besonders für solche Länder, z. B. Ägypten, die den Technikfortschritt aus ökonomischer und ökologischer Betrachtung in sehr kurzer Zeit einzuführen haben. Die Simulationswerkzeuge aller Art werden bekannterweise dazu genutzt, um Fehlentwicklungen zu vermeiden. Je nach Aufgabe und Zielstellung sind diese Werkzeuge fachgerecht anzupassen und zu verifizieren. Im Speziellen werden konventionelle und alternative Antriebskonzepte für Fahrzeuge der verschiedensten Einsatzbedingungen mit einem Simulationswerkzeug bewertet. 1.1 Aufgabenstellung und Zielstellung
5

Desempenho de conjunto motor-gerador utilizando biocombustíveis sob cargas variadas / Performance of engine-generator set using biofuels under varied loads

Rigotte, Marcio Roberto 14 February 2014 (has links)
Made available in DSpace on 2017-07-10T15:14:29Z (GMT). No. of bitstreams: 1 DissertacaoMarcioRRigotte.pdf: 1614115 bytes, checksum: 34d26d4df31cfcd99ebf450c783bee96 (MD5) Previous issue date: 2014-02-14 / The rising demand for energy, coupled with its high cost and the search for sustainability propitiated in recent years an increase in demand for renewable biofuels, including biodiesel. Although Brazil, and specifically Paraná, present agricultural vocation, with diversity of raw materials for biodiesel production, it remains tied to demand compulsory. This work aimed to evaluate the energetic performance of an engine-generator set using diesel oil and biodiesel of different feedstocks. The experiment was conducted in the Experimental Nucleus for Agricultural Engineering (NEEA), State University of West Paraná (UNIOESTE), located in Cascavel - Paraná, using entirely randomized design. The treatments were diesel oil, and three different types of biodiesel (crambe, soybean and waste frying oil) being used pure biodiesel (B100) and the binary blends B10, B20 and B50. The resistive loads used were 1, 2, 3, 4 and 5 kW for each type of fuel, a total of five replications. Among other observations, we evaluated the heating value, specific fuel consumption (CE) and energy efficiency (EE). The best CE was diesel with 0,349 Kg KW h-1 in the load 5 KW, followed by BC20-2 with 0,524 Kg kW h-1 and BC50-3 with 0,433 Kg kW h-1. Biodiesel has the CE nearest of the diesel with increasing resistive load, indicating that its use in operation closest the rated capacity is more efficient. Among the types of biodiesel, the crambe oil showed lower CE, with some values without significant differences (Tukey 5%) of the diesel CE, as BC20-4 with 0,383 Kg kW h-1 and BC10-5 with 0,367 Kg KW h-1. The best EE were DI-5 25,6%, BC100-5 25,5%, BC50-5 25,0%, BS100-5 24,8% and BORF100-5 24,6%. Pure biodiesel (B100) tends to show best EE that the binary blends used. The BC100 showed EE of 9,9 17,8, 21,8, 24,3 and 25,5% respectively for resistive load of 1, 2, 3, 4 and 50 KW. In the range of biodiesel evaluated, crambe oil obtained EE closer to diesel, and the BC100 exceeded diesel EE to the loads 2, 3 and 4 / A crescente demanda por energia, associada a seus elevados custos e a busca por sustentabilidade propiciaram nos últimos anos um aumento na procura por biocombustíveis renováveis, dentre eles o biodiesel. Apesar do Brasil, e especificamente o Paraná, apresentarem vocação agrícola, com diversidade de matérias-primas para obtenção de biodiesel, esta permanece atrelada a demanda compulsória. Este trabalho buscou avaliar o desempenho energético de um conjunto motor-gerador utilizando diesel de petróleo e biodiesel de diferentes matérias primas. O experimento foi conduzido no Núcleo Experimental em Engenharia Agrícola (NEEA), da Universidade Estadual do Oeste do Paraná (UNIOESTE), Cascavel Paraná, utilizando delineamento experimental inteiramente casualizado. Os tratamentos utilizados foram o diesel de petróleo, e três diferentes tipos de biodiesel (crambe, soja e óleo residual de fritura), sendo o biodiesel utilizado puro (B100) e nas misturas binárias B10, B20 e B50. As cargas resistivas utilizadas foram de 1, 2, 3, 4 e 5 KW para cada tipo de combustível, com total de cinco repetições. Entre outras observações, foi avaliado o poder calorífico, o consumo específico (CE) e a eficiência energética (EE). O melhor CE foi o diesel com 0,349 Kg KW h-1 na carga 5 KW, seguido por BC20-2 com 0,524 Kg KW h-1 e o BC50-3 com 0,433 Kg KW h-1. O biodiesel apresenta CE mais próximo do diesel com o aumento da carga resistiva, indicando que sua utilização em operações mais próxima da capacidade nominal é mais eficiente. Dentre os tipos de biodiesel, o de óleo de crambe apresentou menor CE, com alguns valores sem diferenças significativas (Tukey 5%) do CE do diesel, como o BC20-4 com 0,383 Kg KW h-1 e o BC10-5 com 0,367 Kg KW h-1. As melhores EE foram DI-5 25,6%, BC100-5 25,5%, BC50-5 25,0%, BS100-5 24,8% e BORF100-5 24,6%. O biodiesel puro (B100) tende a apresentar melhor EE que as misturas binárias utilizadas. O BC100 apresentou EE de 9,9 17,8 21,8 24,3 e 25,5% respectivamente para as cargas resistivas de 1, 2, 3, 4 e 5 KW. Na gama de biocombustíveis avaliados, o de óleo de crambe obteve EE mais próxima ao do diesel, sendo que BC100 superou EE do diesel nas cargas 2, 3 e 4.
6

Analýza technicko-ekonomických parametrů traktorových souprav v dopravě / Analysis of technical-economic parameters of the tractor kits in transport

Krátký, Martin January 2014 (has links)
This thesis deals with the use of the tractor in agricultural transport. The first part describes the current status in construction of tractor engines, transmissions and chassis that are used in tractors suitable for transport. The theoretical section includes an overview of the legislative requirements that must be followed for the tractor kits in transport on the road. The main objective of this thesis was to evaluate a measuring of fuel consumption and efficiency of the tractor JCB Fastrac 185-65 with two flatbed trailers. For this purpose was created the methodics off terrain measurement, which were carried out for different operation modes of the engine. The results were tabular and graphical processing including determining the accuracy of the method by calculating the relative error of measurement. For comparison a theoretical calculation of the consumed fuel was made. The aim of the measurements was to demonstrate fuel-saving during operation engine in the economic field and get an overview about fuel consumption and efficiency kits.
7

Bewertung von alternativen Antriebskonzepten in Fahrzeugen mit unterschiedlichen Einsatzcharakteristiken

Ahmed, Mohamed 17 December 2004 (has links)
Der weltweit steigende Mobilitätsbedarf führt in der Zukunft zur weiteren Zunahme des Primärenergiebedarfs. Die Rohstoffvorräte unserer Erde sind begrenzt. Rohstoffe, die heute verbraucht werden, stehen zukünftigen Generationen nicht mehr zur Verfügung. Die sparsame und effiziente Nutzung der Ressourcen stellt deshalb den Schlüssel zu einer nachhaltigen Entwicklung dar. Im Mittelpunkt steht dabei der Energieverbrauch. Vor allem die Industrieländer stehen vor der Herausforderung, ihren Verbrauch an begrenzten Energierohstoffen Schritt für Schritt zurückzufahren. Der Wirtschaftsbereich der Europäischen Union kann dabei eine positive Bilanz vorweisen. Eingeschlossen in diese Bilanz ist der Verkehrsbereich. Die modernen Fahrzeugflotten konnten durch die ständige Weiterentwicklung den Streckenkraftstoffverbrauch und die Abgasemissionen erheblich absenken. Eine Entwicklung, die noch nicht am Ende ist. Trotz dieser positiven Tendenz gerät die globale Bilanz durch eine dramatische Zunahme der Fahrzeugflotten, besonders in den Entwicklungsländern, kontinuierlich in eine Schieflage. Die Energieverbräuche steigen und die Ressourcen der Energieträger Öl, Gas und Kohle nehmen ab. Es ist bekannt, dass weltweit besonders in hochentwickelten Industrieländern dieser Entwicklung durch Alternativ-Konzepte entgegengesteuert wird. Im Verkehrsbereich sind dies unter anderem veränderte Fahrzeugkonzepte (z. B. Hybridfahrzeuge) sowie die mittel- und längerfristige Substitution der konventionellen, mineralölstämmigen Kraftstoffe durch Erdgaskraftstoffe (SynFuel, nach der Shell-Mittel-Destillat-Synthese, SMDS, hergestellt) oder Kraftstoffe (Sun Fuel) aus regenerativen Energieträgern wie Restholz, Energiepflanzen oder Biomüll. Diese Entwicklungen werden durch eine permanente Reduzierung der Abgasemissionen von verbrennungsmotorisch angetriebenen Fahrzeugen begleitet. Insbesondere sind dies einerseits die limitierten Schadstoffe, welche in den einzelnen Ländern gesetzlich verankert sind, und andererseits die CO2-Emission, die z. B. noch auf einer freiwilligen Selbstverpflichtung der Automobilindustrie (in Deutschland 140 g/km CO2 – Ausstoß) basieren. Kapitel 1: Einführung 2 Alle diese Entwicklungen gilt es im Voraus abzuschätzen bzw. mit fundierten Betrachtungen in den Entwicklungsprozess einzuordnen. Dies gilt besonders für solche Länder, z. B. Ägypten, die den Technikfortschritt aus ökonomischer und ökologischer Betrachtung in sehr kurzer Zeit einzuführen haben. Die Simulationswerkzeuge aller Art werden bekannterweise dazu genutzt, um Fehlentwicklungen zu vermeiden. Je nach Aufgabe und Zielstellung sind diese Werkzeuge fachgerecht anzupassen und zu verifizieren. Im Speziellen werden konventionelle und alternative Antriebskonzepte für Fahrzeuge der verschiedensten Einsatzbedingungen mit einem Simulationswerkzeug bewertet. 1.1 Aufgabenstellung und Zielstellung
8

Vliv zatížení spalovacího motoru na výstupní parametry traktorových souprav / Effect of engine load on the output parameters of the tractor kits

Paulmichl, Roman January 2013 (has links)
The thesis deals with the current situation in the construction of tractors, particularly engines and accessories. The work includes a methodology for measuring tractor rigs in traffic as well as methodology for plough/plow kits measuring. The measured values were tabulated, graphically presented and analysed. The thesis provides an overview of the issue of the combustion engine load placed on the engine by working conditions in transport, during primary soil tillage with different modes of operation of the tractor set. The thesis aim is to find out the practical effect of the engine load on the monitored parameters and to indicate possibilities for achieving higher efficiency in tractor units with minimum fuel performance
9

Kraftstoffverbrauch durch Entnahme von Zapfluft und Wellenleistung von Strahltriebwerken

Ahlefelder, Sebastian January 2006 (has links) (PDF)
Zapfluft und Wellenleistung wird den Triebwerken entnommen, um die Energie für beispielsweise die Kraftstoffpumpen, das Inflight Entertainment oder die Flügelvorderkantenenteisung zu erzeugen. Diese Energiegenerierung, hat einen Anstieg des Kraftstoffverbrauches zur Folge. Es hat sich herausgestellt, dass die Stelle der Zapfluftentnahme einen starken Einfluss auf den Gradienten des Brennstoffverbrauches hat. Das Projekt beschäftigt sich mit zwei- und dreiwelligen Turbofantriebwerken und untersucht an ihnen, die Effekte der Leistungsnahmen. Als Simulationssoftware wurde GasTurb 8.0 eingesetzt und auf die integrierten Triebwerkskonfigurationen zurückgegriffen. Ziel der Arbeit ist die Ermittlung einer mathematischen Beziehung zur Berechnung des zusätzlichen Kraftstoffmassenstromes infolge einer Zapfluft- oder Wellenleistungsentnahme. So stellt sich die Frage, welche Triebwerksparameter dafür berücksichtigt werden müssen. Eine Wellenleistungsentnahme verursacht beispielsweise einen linearen Anstieg des spezifischen Kraftstoffverbrauches. Ist diese Zunahme, identisch mit der einer Zapfluftentnahme? Am Ende der Kapitel werden die Ergebnisse mit Literaturwerten verglichen und versucht Tendenzen zu erkennen bzw. bestehende zu erhärten.

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