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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.
31

Contribution to the Assessment of the Potential of Low Viscosity Engine Oils to Reduce ICE Fuel Consumption and CO2 Emissions

Ramírez Roa, Leonardo Andrés 02 November 2016 (has links)
[EN] The automotive industry is currently experiencing one of its most rapidly changing periods in recent decades, driven by a growing interest in reducing the negative environmental impacts caused by fossil fuels consumption and the resulting carbon dioxide (CO2) emissions generated during the operation of the internal combustion engine (ICE) which have proven to contribute significantly to Global Warming. Given the fact that a total replacement of the current fleet, dependent of fossil fuels, is unlikely to happen in the immediate future and the urgency to reducing CO2 emissions from transportation in order to tackle Global Warming, it is possible to say that optimizing current ICE technologies and conventional vehicles and engines is a first order priority. Among the technical solutions developed to improve the efficiency of ICE, low viscosity engine oils (LVEO) have emerged as an effective and low-cost method that provides reductions in fuel consumption between 0.5% and 5%. During the development of this thesis, a test plan focused on determining fuel consumption reduction when low viscosity oils are used in light duty vehicles (LDV) and heavy duty vehicles (HDV) were carried out. The test plan has been divided in three parts; the first part was focused on the study of light-duty vehicles (LDV) using one diesel engine representative of the European market. During this part three testing modes were used: comparative motored, fired stationary points and transient homologation cycle tests. All test were performed in the engine test bed. The second part of the study consisted of another comparative test, this time using a different engine oils in a HDV fleet. The study was conducted using the urban buses fleet of the city of Valencia, including 3 buses models , with 2 different powertrain technologies. The third part of the study was focused on the friction coefficient behavior within the engine tribological pairs making comparative tests in two specialized tribometers; one of reciprocating action to simulate the lubrication conditions in the piston ring-cylinder liner contact and a "ball-on-disk" tribometer to simulate the lubrication in the distribution system. The various comparative studies have served to analyze how the friction and fuel consumption responded when LVEO were used both in the ICE and the complete vehicle contexts. The fuel consumption benefit found during the test was used to calculate the carbon footprint reduction when LVEO were used. / [ES] Actualmente la industria de la automoción vive uno de los periodos de cambio más vertiginosos de las últimas décadas, marcado por un creciente interés en reducir los impactos medioambientales negativos generados por el consumo de combustibles fósiles y sus consecuentes emisiones nocivas de dioxido de carbono (CO2) generados durante el funcionamiento del motor de combustión interna alternativo (MCIA). Teniendo en cuenta que el proceso de sustitución de la flota actual por una totalmente independiente de los combustibles fósiles puede tomar varias décadas, y ante la urgencia inmediata de reducir las emisiones de CO2, se puede decir que actualmente es más urgente hacer una optimización de los vehículos con motorizaciones convencionales. Entre las soluciones técnicas que se han desarrollado para mejorar la eficiencia del MCIA destaca la utilización de aceites de baja viscosidad como un método efectivo y de bajo coste de implementación que brinda reducciones del consumo entre el 0.5% y el 5%. Durante el desarrollo de esta tesis se ha llevado a cabo un plan de ensayos enfocado en determinar valores concretos de ahorro de combustible esperados cuando se utilizan aceites de baja viscosidad en vehículos de trabajo ligero y pesado. El plan de estudios se dividió en tres partes; la primera se centró en el estudio de MCIA de vehículos de trabajo ligero, utilizando un motor Diesel representativo del mercado Europeo y llevando a cabo pruebas comparativas en arrastre, puntos de funcionamiento estacionarios y ciclos transitorios de homologación. La segunda parte del estudio consta de otro ensayo comparativo, esta vez utilizando una flota de vehículos de trabajo pesado. El estudio se realizó con la flota de autobuses urbanos de la ciudad de Valencia, incluyéndose 3 modelos de autobuses, con 2 tipos de motorización diferente. La tercera parte del estudio se centró en el comportamiento del coeficiente de friction en los pares tribológicos del motor haciendo ensayos comparativos con tribómetros especializados; uno de movimiento alternativo para simular las condiciones de la interfaz piston-camisa y un "bola y disco" para simular la lubricación en el sistema de distribución, específicamente en la interfaz leva-taqué. Los diversos estudios comparativos han servido para analizar como es la respuesta general de la fricción y el consumo de combustible cuando se usan aceites de baja viscosidad, tanto a nivel de motor como para la totalidad del vehículo, encontrando diferencias de par en los ensayos de arrastre, de consumo específico de combustible en los ensayos de motor en estado estacionario y diferencias totales de consumo de combustible en los ensayos en régimen transitorio y en flota, que a su vez han permitido estimar la reducción esperada en la huella de carbono. / [CA] Actualment la indústria de l'automoció viu un dels períodes de canvi més vertiginoses de les últimes dècades, marcat per un creixent interès en reduir els impactes mediambientals negatius generats pel consum de combustibles fòssils i els seus conseqüents emissions nocives de diòxid de carboni (CO2) generats durant el funcionament del motor de combustió interna alternatiu (MCIA). Tenint en compte que el procés de substitució de la flota actual per una totalment independent dels combustibles fòssils pot prendre diverses dècades, i davant la urgència immediata de reduir les emissions de CO2, es pot dir que actualment és més urgent fer una optimització dels vehicles amb motoritzacions convencionals. Entre les solucions tècniques que s'han desenvolupat per millorar l'eficiència del MCIA destaca la utilització d'olis de baixa viscositat com un mètode efectiu i de baix cost d'implementació que brinda reduccions del consum entre el 0.5% i el 5%. Durant el desenvolupament d'aquesta tesi s'ha dut a terme un pla d'assajos enfocat a determinar valors concrets d'estalvi de combustible esperats quan s'utilitzen olis de baixa viscositat en vehicles de treball lleuger i pesat. El pla d'estudis es va dividir en tres parts; la primera es va centrar en l'estudi de MCIA de vehicles de treball lleuger, utilitzant un motor dièsel representatiu del mercat Europeu i portant a terme proves comparatives en arrossegament, punts de funcionament estacionaris i cicles transitoris d'homologació. la segona part de l'estudi consta d'un altre assaig comparatiu, aquest cop utilitzant una flota de vehicles de treball pesat. L'estudi es va realitzar amb la flota d'autobusos urbans de la ciutat de València, incloent-se 3 models d'autobusos, amb 2 tipus de motorització diferent. La tercera part de l'estudi es va centrar en el comportament del coeficient de friction en els parells tribològics del motor fent assajos comparatius amb tribómetros especialitzats; Un acció reciprocante per simular les condicions del piston camisa i un bola i disc per simular la lubricació en el sistema de distribució. Els diversos estudis comparatius han servit per analitzar com és la resposta general de la fricció i el consum de combustible quan es fan servir olis de baixa viscositat, tant a nivell de motor com la totalitat del vehicle, trobant diferències de bat a els assajos d'arrossegament, de consum específic de combustible en els assajos de motor en estat estacionari i diferències totals de consum de combustible en els assajos en règim transitori i en flota, que al seu torn han permès calcular la reducció en la petjada de carbono. / Ramírez Roa, LA. (2016). Contribution to the Assessment of the Potential of Low Viscosity Engine Oils to Reduce ICE Fuel Consumption and CO2 Emissions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73068
32

Modélisation, dimensionnement et optimisation d'un capteur hybride pour la détection des deux roues motorisées dans le trafic routier / Modeling, optimization and conception of an hybrid sensor for the detection of Powered two wheelers in traffic

Kerbouai, Hamza 02 September 2015 (has links)
Depuis plusieurs années les chiffres de l'insécurité routière montrent la nécessité de développer un outil technologique qui vise à connaitre le comportement de véhicules deux roues motorisés (2RM) afin d'améliorer leursécurité. De cette problématique découle nos travaux de recherche qui s'inscrivent dans le cadre de projet METRAMOTO (MEsure du TRAfic des deux-roues MOTOrisés pour la sécurité routière et l'évaluation des risques)L’objectif principal visé concerne la modélisation, le dimensionnement et l'optimisation d'un capteur hybride constitué d'une part de boucles électromagnétiques et d'autre part de capteurs de chocs piézo-électriques. L’idée consiste à utiliser les boucles électromagnétiques pour discriminer la présence des 2RM de celle des autresvéhicules, associées à des segments piézo-électriques pour détecter le choc produit par le passage des roues desdifférents véhicules, le tout associé à un algorithme de gestion et de traitement de données. Aujourd'hui redimensionnement des systèmes de détection à base de boucles électromagnétiques ou de câble piézo-électriquese fait de manière expérimentale sur des sites contrôlés en utilisant plusieurs types de véhicules. Cette technique gourmande en temps nécessite une série importante d'essais couteux et dangereux. La présente étude a pour butde modéliser les différentes interactions entre le capteur hybride étudié et les véhicules en vue de son dimensionnement. Des modèles électromagnétiques et électromécaniques sont développés pour décrire les différentes interactions se produisant entre les boucles électromagnétiques d'une part, les boucles électromagnétiques et les véhicules d'autre part ainsi que celles des roues de véhicules et le câble piézoélectrique.Sur la base de ces modèles établis, une démarche générale est élaborée conduisant au dimensionnement du capteur hybride pour une route donnée. Nous nous sommes également intéressés au traitement des données issues du capteur hybride pour lesquelles nous proposons une approche d'identification des différentes catégories de véhicules dont les 2RM. Deux configurations de capteurs pour deux routes différentes sont alors proposées.Elles sont associées à des algorithmes de traitement de données permettant l'acquisition des signaux de boucles et de câbles, la distinction des différents types de véhicules, l'estimation de la position des véhicules sur la chaussée ainsi que la mesure de la vitesse de véhicules. / For several years the road safety numbers show the need to develop a technological tool that aims to know thepowered two wheelers vehicles behavior (2PW) to improve their security. From this problematic arise our researchworks that come under the project METRAMOTO (Powered two wheelers traffic measurement for road safety andrisks assessment). The main objective is modeling, sizing and optimization of an hybrid sensor consisted ofelectromagnetic loops and piezoelectric shock sensors. The idea is to use electromagnetic loops to discriminate the2PW presence from the other vehicles, combined with piezoelectric segments to detect the shocks produced by thevehicles wheels passage, all associated with a management algorithm and data processing. Today the sizing of thedetection systems based on electromagnetic loops or piezoelectric cables is done experimentally on controlled sitesusing several vehicles types. This technique requires significant test series which are costly and dangerous. Thisstudy aims to modeling the different interactions between the studied sensor and vehicles in order to its sizing.Electromagnetic and electromechanical models are developed to describe the different interactions that take placebetween electromagnetic loops on the one hand, between electromagnetic loops and vehicles on the other handand those between vehicle wheels and piezoelectric cable. On the basis of established models, a general approachis elaborated driving to sizing the hybrid sensor for any given road. We are also interested to the data processingcoming from the hybrid sensor for which we propose an approach to identifying the different vehicle categoriesincluding the 2PW. Two sensor configurations for two different roads are then proposed. They are associated atdata processing algorithms allowing the acquisition of loops and cables signals, the distinction between the differentvehicles classes, the estimation of the vehicles positions on the road and the measuring of their speed.
33

Evaluating the potential of truck electrification and its implementation from user and agency perspectives

Theodora Konstantinou (5930705) 27 July 2022 (has links)
<p>  </p> <p>The trucking industry seems to be resistant to electrification, even though truck electrification can lead to large societal as well as user benefits. This dissertation develops a framework to inform policy making and enhance electric vehicle (EV) preparedness in the trucking industry through the study of two interrelated elements: (a) the adoption of electric trucks and (b) the appropriate implementation of electric truck technology. These two elements cover the user perspective, which is not adequately studied, and the agency perspective, which is pivotal in the decision-making process. Specifically, this study addressed the following research questions: (i) which factors affect the purchase decisions of truck fleet managers or owners for electric trucks? (ii) what is the ranking of and interrelationships between the barriers to the adoption of electric trucks? (iii) which location criteria should be considered for the strategic implementation of dynamic wireless charging (DWC) in a freight transportation network and where should this technology be located based on these criteria, and (iv) what is the impact of electric truck adoption on highway revenue and potential of alternative funding mechanisms to recover the revenue loss?</p> <p>For the adoption of electric trucks, a stated preference survey was designed and distributed online to truck fleet managers/owners in the U.S., gathering 200 completed responses. Statistical and multi-criteria decision-making approaches were employed to identify the factors that affect the purchase intentions of truck fleet managers and explore the barriers to electric truck adoption. The results showed that the purchase intentions of truck fleet managers are affected by trucking firm and truck fleet characteristics, behavioral factors/opinions regarding electric trucks, and awareness of innovative charging technologies. Furthermore, electric truck adoption would be accelerated if stakeholders focused on the barriers related to the business model, product availability, and charging time. Additionally, electric truck adopters and non-adopters may not be viewed as one homogenous group, since differences were found in the ranking and interrelationships of barriers to electric truck adoption between these two groups. </p> <p>The implementation of electric truck technology was examined based on the truck fleet managers’ survey, secondary data sources and the case of Indiana, U.S. A multi-criteria decision-making spatial approach was proposed to identify the candidate locations for the deployment of DWC. It was concluded that the most suitable locations for DWC lanes were on interstates, near airports and ports and away from EV charging stations. A data-driven framework was also developed to quantify the impact of electric truck adoption and estimate the optimal fee for each truck to recover the revenue loss. Using the market penetration levels estimated based on the survey data collected, the average annual fuel tax revenue loss for Indiana was approximately $349M. To maintain the same tax revenue per vehicle, annual fees ranging from $969 (in 2021) to $1,243 (in 2035) for single-unit trucks and $6,192 to $7,321 for combination trucks would be needed. To address public relations problems of EV fee implementation, this study also discussed alternative mitigation measures: a vehicle-miles-traveled fee and a pay-as-you-charge fee.</p> <p>In summary, this dissertation contributes to the body of literature by providing significant insights regarding the perspectives of truck fleet managers for electric trucks as well as a comprehensive list of all the location criteria for DWC. The proposed frameworks and study findings can be used by policymakers and other major stakeholders of the EV ecosystem to frame certain strategies to accelerate electric truck adoption, identify the most suitable locations for charging infrastructure, better understand the impact of electric trucks on the highway revenue, and provide the groundwork for developing EV roadmaps.</p>

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