• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 80
  • 15
  • 15
  • 8
  • 7
  • 1
  • 1
  • 1
  • Tagged with
  • 159
  • 159
  • 159
  • 49
  • 47
  • 38
  • 32
  • 28
  • 27
  • 27
  • 25
  • 25
  • 25
  • 24
  • 22
  • 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.
81

Thermal Feasibility and Performance Characteristics of an Air-Cooled Axial Flow Cylindrical Power Inverter by Finite Element Analysis

Tawfik, Jonathan Atef 01 May 2011 (has links)
The purpose of the present study is to determine the thermal feasibility of an air-cooled power inverter. The inverter circuitry layout is designed in tandem with the thermal management of the devices. The cylindrical configuration of the air-cooled inverter concept accommodates a collinear axial air blower and a cylindrical capacitor with inverter cards oriented radially between them. Cooling air flows from the axial fan around the inverter cards and through the center hole of the cylindrical capacitor. The present study is a continuation of the thermal feasibility study conducted in fiscal year 2009 for the Oak Ridge National Laboratory to design a power inverter with a radial inflow cylindrical configuration. Results in the present study are obtained by modeling the inverter concept in computer simulations using the finite element method. Air flow rate, ambient air temperature, voltage, and device switching frequency are studied parametrically. Inlet air temperature was 50°C for all the results reported. Transient and steady-state simulations are based on inverter current that represents the US06 supplemental federal test procedure from the US EPA. The source of heat to the system comes from the power dissipated in the form of heat from the switches and diodes and is modeled as a function of the voltage, switching frequency, current, and device temperature. Since the device temperature is a result as well as an input variable, the steady-state and transient solution are iterative on this parameter. The results demonstrate the thermal feasibility of using air to cool an axial-flow power inverter. This axial inflow configuration decreases the pressure drop through the system by 63% over the radial inflow configuration, and the ideal blower power input for an inlet air flow rate of 540 cfm is reduced from 936 W to 312 W for the whole inverter. When the model is subject to one or multiple current cycles, the maximum device temperature does not exceed 164°F (327°F) for an inlet flow rate of 270 cfm, ambient temperature of 120°C, voltage of 650 V, and switching frequency of 20 kHz. Although the maximum temperature in one cycle is most sensitive to ambient temperature, the ambient temperature affect decays after approximately half the duration of one cycle. Of the parametric variables considered in the transient simulations, the system is most sensitive to inlet air flow rate.
82

Multi-objective Optimization of Plug-in Hybrid Electric Vehicle (PHEV) Powertrain Families considering Variable Drive Cycles and User Types over the Vehicle Lifecycle

Al Hanif, S. Ehtesham 02 October 2015 (has links)
Plug-in Hybrid Electric vehicle (PHEV) technology has the potential to reduce operational costs, greenhouse gas (GHG) emissions, and gasoline consumption in the transportation market. However, the net benefits of using a PHEV depend critically on several aspects, such as individual travel patterns, vehicle powertrain design and battery technology. To examine these effects, a multi-objective optimization model was developed integrating vehicle physics simulations through a Matlab/Simulink model, battery durability, and Canadian driving survey data. Moreover, all the drivetrains are controlled implicitly by the ADVISOR powertrain simulation and analysis tool. The simulated model identifies Pareto optimal vehicle powertrain configurations using a multi-objective Pareto front pursuing genetic algorithm by varying combinations of powertrain components and allocation of vehicles to consumers for the least operational cost, and powertrain cost under various driving assumptions. A sensitivity analysis over the foremost cost parameters is included in determining the robustness of the optimized solution of the simulated model in the presence of uncertainty. Here, a comparative study is also established between conventional and hybrid electric vehicles (HEVs) to PHEVs with equivalent optimized solutions, size and performance (similar to Toyota Prius) under both the urban and highway driving environments. In addition, breakeven point analysis is carried out that indicates PHEV lifecycle cost must fall within a few percent of CVs or HEVs to become both the environmentally friendly and cost-effective transportation solutions. Finally, PHEV classes (a platform with multiple powertrain architectures) are optimized taking into account consumer diversity over various classes of light-duty vehicle to investigate consumer-appropriate architectures and manufacturer opportunities for vehicle fleet development utilizing simplified techno-financial analysis. / Graduate / 0540 / 0548 / ehtesham@uvic.ca
83

ENERGY REDUCTION IN AUTOMOTIVE PAINT SHOPS A REVIEW OF HYBRID/ELECTRIC VEHICLE BATTERY MANUFACTURING

Arenas Guerrero, Claudia Patricia 01 January 2010 (has links)
Automotive industry is facing fundamental challenges due to the rapid depletion of fossil fuels, energy saving and environmental concerns. The need of sustainable energy development has motivated the research of energy reduction and renewable energy sources. Efficient use of energy in vehicle manufacturing is demanded, as well as an alternative energy source to replace gasoline powered engines. In this thesis, we introduce a case study at an automotive paint shop, where the largest amount of energy consumption of an automotive assembly plant takes place. Additionally, we present a summary of recent advances in the area of hybrid and electrical vehicles battery manufacturing, review commonly used battery technologies, their manufacturing processes, and related recycling and environmental issues. Our study shows that energy consumption in paint shops can be reduced substantially by selecting the appropriate repair capacity, reducing the number of repainted jobs and consuming less material and energy. Also, it is seen that considerable effort needs to be devoted to the development of batteries for hybrid and electric vehicles in the near future, which will make this area challenging and research opportunities promising.
84

Modelagem, controle e otimização de consumo de combustível para um veículo híbrido elétrico série-paralelo. / Modeling, control and application of dynamic programming to a series-parallel hydrid electric vehicle.

Ivan Miguel Trindade 16 May 2016 (has links)
O principal objetivo dos veículos híbridos é diminuir o consumo de combustível em relação a veículos convencionais. Para isso, existe a necessidade de realizar a integração dos diferentes sistemas do trem-de-força e coordenar o seu funcionamento através de estratégias de controle. Tais estratégias são desenvolvidas e simuladas em conjunto com um modelo computacional da planta do veículo antes de serem aplicadas em uma unidade de controle eletrônica. O presente estudo tem como objetivo analisar o gerenciamento de energia em um veículo híbrido elétrico não-plugin do tipo série-paralelo visando à diminuição de consumo de combustível. O método de otimização global é utilizado para encontrar as variáveis de controle que resultam no mínimo consumo de combustível em um determinado ciclo de condução. Na primeira etapa, um modelo computacional da planta do veículo e da estratégia de controle não-ótima são criados. Os resultados obtidos da simulação são então comparados com dados experimentais do veículo operando em dinamômetro de chassis. A seguir, o método de otimização global é aplicado ao modelo computacional utilizando programação dinâmica e tendo como objetivo a minimização do consumo de combustível total ao final do ciclo. Os resultados mostram considerável redução do consumo de combustível utilizando otimização global e tendo como variável de controle não só a razão de distribuição de torque mas também os pontos de operação do motor de combustão. Os modelos computacionais criados nesse trabalho são disponibilizados e podem ser usados para o estudo de diferentes estratégias de controle para veículos híbridos. / The main goal of hybrid electric vehicles is to decrease engine emission and fuel consumption levels. In order to realize this, one must perform the powertrain system integration and coordinate its operation through supervisory control strategies. These control strategies are developed in a simulation environment containing the plant model of the powertrain before they can be implemented in a real-time control unit. The goal of this work is to analyze the energy management strategy which minimizes the fuel consumption in a series-parallel non-plugin hybrid electric vehicle. Global optimization is used for finding the control variables that result in the minimum fuel consumption for a specific driving cycle. In a first stage, a computational model of vehicle plant and non-optimal control strategy are created. The results from the simulation are compared against experimental data from chassis dynamometer tests. Next, a global optimization strategy is applied using dynamic programming in order to minimize total fuel consumption at the end of the driving cycle. The results from the optimization show a considerable fuel consumption reduction having as control variables not only the torque-split strategy but also the engine operating points. As contribution from this work, the computational models are made available and can be used for analyzing different control strategies for hybrid vehicles.
85

Distributed Model Predictive Control with Application to 48V Diesel Mild Hybrid Powertrains

LIU, YUXING 30 September 2019 (has links)
No description available.
86

Zkoumání teplotních změn olověného akumulátoru v režimu hybridních vozidel / Investigation of temperature changes in the lead-acid battery system for hybrid electric vehicles

Kadrnka, Petr January 2012 (has links)
The lead-acid batteries are most commonly used electrochemical power source. The lead-acid battery is the oldest type of secondary battery cells. This lead-acid batteries have a great use in hybrid electric vehicles (HEVs), which operate in different modes of vehicle operation. This is related to changes in battery temperature, caused by Joule heat taking place during discharging and chargingg the battery in a vehicle operation. The lead-acid batteries in hybrid electric vehicles work in mode PSoC.
87

Zkoumání vlivu přítlaku na životnost olověných akumulátorů pro hybridní elektrická vozidla / Exploring the influence of pressure on the life of lead acid batteries for hybrid electric vehicles

Čech, Tomáš January 2012 (has links)
The goal of the thesis is to study literature and to become familiar with problems of accumulators operating in the mode of hybrid electric vehicles (HEV). To work up problems of a potential impact of the influence on the system of the lead accumulator. Assemble the experimental cells with discontinuous system of parallel fins and to treat them with different operating modes. Then to evaluate the results.
88

THE OPTIMIZATION OF THE ELECTRICAL SYSTEM VOLTAGE RANGE OF MILD HYBRID ELECTRIC VEHICLE

Yansong Chen (7036457) 16 December 2020 (has links)
<p>The optimization of the electrical system voltage range of a mild hybrid electric vehicle is examined in this research study. The objective is to evaluate and propose the optimized vehicle voltage level for the mild hybrid electric vehicle from both technical and economic aspects. The approach is to evaluate the fuel economy improvement from the mild hybrid electric vehicle of various voltage level for the cost benefit study. The evaluation is conducted from the vehicle system level with discussions of components selection for system optimization. Autonomie, a simulation tool widely used by academic and automotive industry, is used for the vehicle simulation and fuel economy evaluation. The cost analysis is based on the system cost factoring in the component cost based forecasted production volume. </p> <p>The driver for this study is to propose an optimized voltage for the mild hybrid electric vehicle for the vehicle manufacturers and suppliers to standardize the implementation to meet the fuel economy and emission requirements and vehicle power demand. The standardization of the vehicle voltage level can improve design and development efficiency, reusability and reduce cost in developing non-standard voltage levels of the mild hybrid vehicle. The synergy in standardized voltage level for the mild hybrid vehicle can accelerate technology implementation toward mass production to meet regulatory emission and fuel economy requirements. </p>
89

A Decomposition-based Multidisciplinary Dynamic System Design Optimization Algorithm for Large-Scale Dynamic System Co-Design

Sherbaf Behtash, Mohammad 25 October 2018 (has links)
No description available.
90

Control of Criteria Emissions and Energy Management in Hybrid Electric Vehicles with Consideration of Three-Way Catalyst Dynamics

Jankord, Gregory J. January 2020 (has links)
No description available.

Page generated in 0.3709 seconds