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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

Dinâmica longitudinal de veículos pesados = forças resistivas e outros fatores de influência no consumo de combustível / Heavy vehicle longitudinal dynamics : resistive forces and other factors that influence on fuel consumption

Gasparini, Ricardo Ferreira 16 August 2018 (has links)
Orientador: Franco Giuseppe Dedini / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T17:28:53Z (GMT). No. of bitstreams: 1 Gasparini_RicardoFerreira_M.pdf: 3191496 bytes, checksum: 30659cea3db8d634961f1bb5d3fba1fa (MD5) Previous issue date: 2010 / Resumo: O principal objetivo deste trabalho é estudar a interação de veículos comerciais com o meio e a influência de suas características dinâmicas no consumo de combustível. O primeiro passo é o levantamento dos parâmetros influentes na modelagem para o desempenho veicular, seja este baseado em métodos de energia, seja baseado em métodos de forças. As relações do veículo com o ambiente serão tratadas como aspectos influentes e incluídas no modelo de desempenho. As simulações e a modelagem final foram implementadas no programa GTDrive, software comercial. Conhecendo essas interações entre veículo e meio, e a influência destas interações no consumo de combustível, deseja-se propor uma nova abordagem no desenvolvimento de projetos automotivos para futuras aplicações em veículos comerciais, visando a redução do consumo de combustível no Brasil / Abstract: The main focus of this work is the study of interaction between commercial vehicle and the environment and also the influence of their dynamic characteristics in the fuel consumption. The first step of this work is to analyze the types of vehicle dynamic modeling based on energy and based on forces (Newton). The relationship between the vehicle and it.senvironment will be considered as influent aspects and should be included into vehicle dynamic modeling. By understanding this relationships and their influence in the fuel consumption it is possible to propose an approach to develop new automotive projects for future commercial vehicle applications focus on fuel consumption and taking into account the Brazilian reality / Mestrado / Dinâmica / Mestre em Engenharia Automobilistica
32

Valoração de tecnologias fora de ciclo quanto ao consumo de combustível. / Sem título em inglês

Mauricio Leite Mendes 12 April 2018 (has links)
Em um mercado altamente competitivo, como o automobilístico, as empresas dependem de competir com seus concorrentes nas mesmas condições para manterem-se no mercado. Obter incentivos fiscais é uma questão de sobrevivência, pois para manter os preços dos seus produtos competitivos, é obrigatório obter o mesmo nível de incentivos dos concorrentes. Para a obtenção de incentivos, uns dos requisitos considerados pelas legislações é a eficiência energética e consumo de combustível. Dentre as tecnologias a serem empregadas nos veículos com o objetivo de reduzir o consumo de combustível estão as tecnologias ditas como fora de ciclo. Estas quando avaliadas somente com os ciclos padrões de rodagem atualmente utilizados, não apresentam ganhos compatíveis com os verificados em rodagens realizadas por clientes. Para demonstrar o potencial destas tecnologias, foram realizados estudos sobre os trajetos mensurados pela Companhia de Engenharia de Tráfego de São Paulo em termos de volumes, velocidades e altimetria, e foram elencadas rotas que representassem condições de tráfego no município de São Paulo, comuns a grandes cidades brasileiras. Após a escolha das rotas a serem estudadas, foram realizadas rodagens com veículo instrumentado e registradas as informações de consumo de combustível, velocidades, acelerações, regimes do motor entre outras, com e sem a aplicação da tecnologia fora de ciclo. Neste estudo foi utilizada a tecnologia Coasting. Para analisar as variações de consumo de combustível observadas de modo a extrair delas o efeito da tecnologia Coasting, foram utilizadas duas abordagens: comparação dos resultados do consumo total nos trajetos completos como função da velocidade média; e análise do consumo instantâneo em trechos específicos de uma mesma rota com acionamento ou não da tecnologia. Os resultados são comparados com aqueles obtidos em programas de quantificação desenvolvidos na Europa. / In a highly competitive market like the automotive, companies depend on competing with their competitors in the same conditions to stay in the market. Getting tax incentives is a matter of survival because to keep the prices of your products competitive, it is mandatory to get the same level of incentives from competitors. To obtain incentives, one of the requirements considered by the legislations is energy efficiency and fuel consumption. Among the technologies to be used in vehicles with the aim of reducing fuel consumption are the so-called off-cycle technologies. When evaluated only with the standard running cycles currently in use, the obtained values are not compatible with those recorded at customer-driven runs. To demonstrate the potential of these technologies, studies were carried out on routes measured by the Traffic Engineering Company of São Paulo in terms of volumes, speeds and altimetry, and some routes were identified that represent traffic conditions in São Paulo municipality and that are common in large Brazilian cities. After the election of the routes to be studied, vehicleinstrumented taxiing was carried out and information on fuel consumption, speeds, accelerations, engine regimes and others were recorded, with and without the application of off-cycle technology. In the studies, Coasting technology was the one applied. To analyze the observed fuel consumption variations, in order to extract the effect of Coasting technology, two approaches were utilized: comparison of total fuel consumption in the chosen routes as a function of average speed; and analysis of instantaneous fuel consumption on specific stretches of the same route, switching-on and off the technology. The results are compared with the ones obtained from quantification programs developed in Europe.
33

Projeção e avaliação do consumo de combustíveis fósseis para a geração de eletricidade na Venezuela : Projection of fossil fuels consumption for electricity generation in Venezuela / Projection of fossil fuels consumption for electricity generation in Venezuela

Vidoza Guillen, Jorge Alejandro, 1988- 24 August 2018 (has links)
Orientador: Waldyr Luiz Ribeiro Gallo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T19:50:08Z (GMT). No. of bitstreams: 1 VidozaGuillen_JorgeAlejandro_M.pdf: 6817089 bytes, checksum: a261816320a3076eeb75253558a35d02 (MD5) Previous issue date: 2014 / Resumo: O objetivo principal deste trabalho é analisar os impactos futuros da aplicação de políticas energéticas mais eficientes no consumo de combustíveis fósseis para a geração de eletricidade na Venezuela. Os recursos principais utilizados na indústria elétrica são: gás natural, óleo diesel e óleo combustível. Esta análise foi feita projetando o desenvolvimento a médio prazo do setor elétrico em um horizonte de tempo de quinze anos. Diferentes cenários de crescimento econômico e mudanças tecnológicas foram assumidos a fim de realizar essas projeções. A ferramenta de simulação usada foi o programa de planejamento energético LEAP. Após simular um esquema de demanda e fixar as características de desenvolvimento de cada cenário, obtiveram-se os resultados de consumo e disponibilidade. O cenário de alto crescimento econômico e baixa eficiência (CRE) apresenta uma importação de gás natural de 15% da demanda total. Por outro lado, o cenário de baixo crescimento econômico e baixa eficiência (BAS), além de importações de gás natural, apresenta uma importação direta de eletricidade de 8% da demanda total. Estes cenários com baixa eficiência deixariam a Venezuela vulnerável em termos de segurança energética. Devido ao grande risco que apresentam esses cenários, é mais provável que ocorra maior investimento na produção e exploração interna de recursos energéticos, que investimentos em infraestrutura para importação. O óleo diesel apresenta cenários menos divergentes e mais independentes das hipóteses utilizadas. O consumo de óleo combustível depende em grande parte da disponibilidade dos outros dois e da conjuntura econômica, porque, para deixar de utilizar este recurso são necessárias mudanças mais estruturais nas usinas de geração e refinarias. Deve-se alcançar uma utilização mais eficiente dos combustíveis líquidos, que atenue também o déficit temporário de gás natural. O incremento da eficiência nesses processos é vital para a economia venezuelana já que poderia incrementar a quantidade de petróleo cru disponível para a exportação / Abstract: The main goal of this work was to make a prospective analysis on the impacts of efficient energy policies application, regarding the fossil fuel consumption for electricity generation in Venezuela. The main fossil resources used for the electric power industry are: natural gas, diesel and fuel oil. The analysis was done by projecting the middle-term development of the electrical sector in a fifteen year time horizon. Different conditions of economic growth and technology were assumed in order to carry out these projections. Energy planning software LEAP was the simulation tool used in this study. Results on consumption and availability were finally obtained after simulating a demand scheme and fixing the development characteristics of every scenario. The high-economic growth and low-efficiency scenario (CRE) results in gas imports that correspond to 15% of total demand. The low-economic growth and low-efficiency scenario (BAS), besides of resulting in natural gas imports, also presents electrical energy imports of 8% of the total demand. These low-efficiency scenarios would make Venezuela vulnerable in terms of energy security. Because of the high risks presented in these scenarios, investments in the inner production and exploitation of energy resources are more likely to happen, rather than investments in imports infrastructure, such as ports, piping or power transmission connections. Diesel oil presents less divergent and more independent scenarios, for the chosen hypotheses. Consumption of fuel oil depends on the availability of the other analyzed fuels. To reduce the consumption of this resource, more structural changes would be needed, such as retrofitting of oil refineries and power generation units. A more efficient use of liquid fossil fuels must be achieved, also helping to reduce the temporary natural gas shortage. Efficiency increase in these processes is vital to Venezuelan economy as it could increase the available quantity of petroleum for exports / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos
34

Modelling real-world driving, fuel consumption and emissions of passenger vehicles : a case study in Johannesburg

Goyns, Philip Hugh 16 November 2009 (has links)
D. Phil. (Energy Studies) / Quantifying energy consumed and emissions produced by transport is essential for effective policy formulation and urban environmental management. Current first-world methods for determining vehicle emissions factors are technology and resource intensive, and results cannot be applied directly to cities in other parts of the world. There is a need for alternative cost-effective and accurate methods for determining real-world fuel consumption and emissions from vehicles in cities of the developing world. In this thesis, a new emissions simulation and inventory model is developed and implemented as a software tool. A novel application of low cost on-board diagnostics equipment and Global Positioning System sensors is devised to survey engine-operating parameters, driving conditions and vehicle usage profiles needed by the model. An emissions inventory is produced for the City of Johannesburg using the software tool and surveying method to demonstrate the overall process. The core contribution of this thesis is the logical development of data structures and software tools which link base engine-operating patterns (of engine speed and engine load), derived from the literature, to measured engine-operating patterns and vehicle activity from real-world driving. A range of real-world driving cycles and emission factors published by the Swiss Institute of Materials Science and Technology are transformed to produce the base engine-operating patterns and their corresponding emissions factors. The calculation of emission factors for real-world driving involves matching measured engineoperating patterns to combinations of the base engine-operating patterns using numerical methods. The method is validated using a cross validation technique. The emissions inventory application integrates measured engine-operating patterns, vehicle activity, fleet structure, fuel sales and the emissions simulation procedure to calculate total emissions. Fuel consumption and emissions of interest are CO2, CO, HC, NOx. Measurements of engine operating parameters and vehicle usage patterns were recorded for 30 privately owned passenger vehicles from the Johannesburg fleet. The selection included Euro-0 (a mixture of pre Euro-1 vehicles), Euro-2 and Euro-3 petrol vehicles, and Euro-2 diesel private passenger vehicles. Fifteen billion vehicle kilometres were driven in Johannesburg by private passenger vehicles per year consuming 325 million litres of diesel and 1 524 billion litres of petrol. iv Total emissions were estimated to be 4.13 Mt CO2, 82.77 kt CO, 9.15 kt HC, and 24.49 kt NOx. Between 88 and 93% of the total emissions were from vehicles which fall into the Euro-0 petrol category. Diesel vehicles did not make a significant contribution to CO and HC emissions but contributed 14% of the NOx and 19% of the CO2 emissions. During weekdays, 28 to 31% and 25 to 27% of the total fuel consumption and emissions were due to the morning commute and the evening commute periods respectively. Although minibus taxis, buses, freight and vehicle age significantly impact on total fuel consumption and emissions in cities they were not considered within the scope of this study. Vehicle usage patterns are analysed to produce spatial maps and diurnal charts of congestion on suburban roads, streets and highways within the Johannesburg municipal area. Times and locations of congestion are presented in terms of a standard congestion index, and suggestion given on how and where congestion problems could be addressed. This study shows that vehicle emissions inventories can be cost effectively produced by surveying engine-operating parameters and vehicle usage profiles using on-board diagnostics and Global Positioning System sensors and simulating emissions factors using a new emissions simulation and emissions inventory model.
35

Effect of Pavement-Vehicle Interaction on Highway Fuel Consumption and Emission

Jiao, Xin 13 November 2015 (has links)
Vehicle fuel consumption and emission are two important effectiveness measurements of sustainable transportation development. Pavement plays an essential role in goals of fuel economy improvement and greenhouse gas (GHG) emission reduction. The main objective of this dissertation study is to experimentally investigate the effect of pavement-vehicle interaction (PVI) on vehicle fuel consumption under highway driving conditions. The goal is to provide a better understanding on the role of pavement in the green transportation initiates. Four study phases are carried out. The first phase involves a preliminary field investigation to detect the fuel consumption differences between paired flexible-rigid pavement sections with repeat measurements. The second phase continues the field investigation by a more detailed and comprehensive experimental design and independently investigates the effect of pavement type on vehicle fuel consumption. The third study phase calibrates the HDM-IV fuel consumption model with data collected in the second field phase. The purpose is to understand how pavement deflection affects vehicle fuel consumption from a mechanistic approach. The last phase applies the calibrated HDM-IV model to Florida’s interstate network and estimates the total annual fuel consumption and CO2 emissions on different scenarios. The potential annual fuel savings and emission reductions are derived based on the estimation results. Statistical results from the two field studies both show fuel savings on rigid pavement compared to flexible pavement with the test conditions specified. The savings derived from the first phase are 2.50% for the passenger car at 112km/h, and 4.04% for 18-wheel tractor-trailer at 93km/h. The savings resulted from the second phase are 2.25% and 2.22% for passenger car at 93km/h and 112km/h, and 3.57% and 3.15% for the 6-wheel medium-duty truck at 89km/h and 105km/h. All savings are statistically significant at 95% Confidence Level (C.L.). From the calibrated HDM-IV model, one unit of pavement deflection (1mm) on flexible pavement can cause an excess fuel consumption by 0.234-0.311 L/100km for the passenger car and by 1.123-1.277 L/100km for the truck. The effect is more evident at lower highway speed than at higher highway speed. From the network level estimation, approximately 40 million gallons of fuel (combined gasoline and diesel) and 0.39 million tons of CO2 emission can be saved/reduced annually if all Florida’s interstate flexible pavement are converted to rigid pavement with the same roughness levels. Moreover, each 1-mile of flexible-rigid conversion can result in a reduction of 29 thousand gallons of fuel and 258 tons of CO2 emission yearly.
36

A preliminary study of configuration effects on the drag of a tractor-trailer combination

Wacker, Thomas January 1985 (has links)
The effect of configuration changes and add-on devices on the drag reduction of a tractor-trailer is studied through wind tunnel tests using two 1/12-scale models. The configuration changes involve ground clearance, tractor-trailer gap, roof angle and back inclination while add-on devices include flow deflectors, skirts and gap seals. Moving surface boundary layer control as a means of drag reduction is also attempted. Both drag and pressure data are obtained to help identify local contributions. Results suggest that an optimum combination of configuration parameters can reduce drag up to 17% while the add-on devices resulted in a further decrease by a modest amount. The results with moving surface boundary layer control proved to be inconclusive. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate
37

Combustion of natural gas and gasoline in a spark-ignition engine

Baets, Jozef Eduard January 1982 (has links)
This thesis presents the results of an investigation of the differences in combustion between gasoline and natural gas in a spark-ignition engine. Combustion development is influenced by calorific value, specific heat, flame speed and the gaseous or liquid state of the fuel. Simple simulation programs were set up to investigate the effects of low flame speed and higher specific heat of the fuel-air mixture. Actual performance was measured on a single cylinder test engine using ionization probes as flame detectors and a pressure pick-up. The experimental results show that longer ignition delay and limited flame speed at high pressure and temperature are the main reasons for' the power loss of natural gas at high engine speed; this is in addition to the basic loss due to the replacement of air by gaseous fuel in the cylinder. From calculations, it was learned that specific heat and dissociation differences had little effect on power. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate
38

Microscopic Fuel Consumption and Emission Modeling

Ahn, Kyoungho 06 January 1999 (has links)
Mathematical models to predict vehicle fuel consumption and emission metrics are presented in this thesis. Vehicle fuel consumption and emissions are complex functions to be approximated in practice due to numerous variables affecting their outcome. Vehicle energy and emissions are particularly sensitive to changes in vehicle state variables such as speed and acceleration, ambient conditions such as temperature, and driver control inputs such as acceleration pedal position and gear shift speeds, among others. Recent empirical studies have produced large amounts of data concerning vehicle fuel consumption and emissions rates and offer a wealth of information to transportation planners. Unfortunately, unless simple relationships are found between fuel consumption and vehicle emission metrics, their application in microscopic traffic and macroscopic planning models becomes prohibitive computationally. This thesis describes the development of microscopic energy and emission models using nonlinear multiple regression and neural network techniques to approximate vehicle fuel consumption and emissions field data. The energy and emission models described in this thesis utilized data collected by the Oak Ridge National Laboratory. The data include microscopic fuel consumption and emission measurements (CO, HC, and NOx) for eight light duty vehicles as a function of vehicle speed and acceleration. The thesis describes modeling processes and the tradeoffs between model accuracy and computational efficiency. Model verification results are included for two vehicle driving cycles. The models presented estimate vehicle fuel consumption within 2.5% of their actual measured values. Vehicle emissions errors fall in the range of 3-33% with correlation coefficients ranging between 0.94 and 0.99. Future transportation planning studies could also make use of the modeling approaches presented in the thesis. The models developed in this study have been incorporated into a microscopic traffic simulation tool called INTEGRATION to further demonstrate their application and relevance to traffic engineering studies. Two sample Intelligent Transportation Systems (ITS) application results are included. In the case studies, it was found that vehicle fuel consumption and emissions are more sensitive to the level of vehicle acceleration than to the vehicle speed. Also, the study shows signalization techniques can reduce fuel consumption and emissions significantly, while incident management techniques do not affect the energy and emissions rates notably. / Master of Science
39

Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities

Tu, Ran 20 June 2016 (has links)
The environmental impact of a transportation system is critical in the assessment of the transportation system performance. Eco-Cooperative Adaptive Cruise Control (Eco-CACC) systems attempt to minimize vehicle fuel consumption and emission levels by controlling vehicle speed and acceleration levels. The majority of previous research efforts developed and applied Eco-CACC systems on either freeway or signalized intersections independently on simple and small transportation networks without consideration of the interaction among these controls. This thesis extends the state-of-the-art in Eco-CACC evaluation by conducting a comprehensive evaluation on a complex network considering Eco-CACC control on both freeways and arterials individually and simultaneously. The goal of this study is to compare Eco-CACCs on arterial facilities (Eco-CACC-A), freeway facilities (Eco-CACC-F) and both facilities (Eco-CACC-F+A). The effects of Eco-CACC are evaluated considering various Measures of Effectiveness (MOEs), including: average vehicle delay, fuel consumption, and emission levels using simulated results from INTEGRATION, a microscopic traffic assignment and simulation software, considering different freeway speed limits, traffic demand levels and system market penetration rates. In total, 19 traffic scenarios for each of the four different cases (Eco-CACC-A, Eco-CACC-F and Eco-CACC-F+A plus a base no control case) were tested. In total 760 simulation runs were conducted (4 cases * 19 scenarios * 10 repetitions). T-tests and pairwise mean comparison (Tukey HSD) were conducted to identify any statistical differences between control cases and the base case from the simulation results. This thesis shows that arterial and freeway Eco-CACCs can work well together and their effects will be largely influenced by network characteristics. / Master of Science
40

Fuel optimal rendezvous including a radial constraint

Vasudevan, Gopal January 1986 (has links)
Fuel-optimal rendezvous in orbit is examined using thrust-impulses and coasting arcs. Necessary conditions for the optimality of fuel-optimal rendezvous with and without radial constraints are derived. These conditions are then used to verify the optimality of trajectories obtained from a parameter-optimization technique. For rendezvous problems with radial constraint, locally optimal trajectories include constrained arcs or touch-point arcs. Numerical procedures to compute the costates and the jumps in the costates at the touch point and at the entry point to the constraint arc are provided. Locally optimal solutions for non-optimal trajectories with a minimum radius-constraint are obtained using criteria due to Lion and Handelsmann. Numerical solutions show that multiple-impulse trajectories almost always result in a lower cost function than the corresponding two impulse trajectories. It is also observed that trajectories comprised of only touch-point arcs can often be improved by using an additional impulse. / M. S.

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