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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

A Plug-in Hybrid Electric Vehicle Loss Model to Compare Well-to-Wheel Energy Use from Multiple Sources

Johnson, Kurt M. 16 July 2008 (has links)
Hybrid electric vehicles (HEV) come in many sizes and degrees of hybridization. Mild hybrid systems, where a simple idle stop strategy is employed, eliminate fuel use for idling. Multiple motor hybrid systems with complex electrically continuously variable transmissions in passenger cars, SUVs and light duty trucks have large increases in fuel economy. The plug-in hybrid electric vehicle (PHEV) takes the electrification of the automobile one step further than the HEV by increasing the battery energy capacity. The additional capacity of the battery is used to propel the vehicle without using onboard fuel energy. Commercial software of great complexity and limited availability is often used with sophisticated models to simulate powertrain operation. A simple method of evaluating technologies, component sizes, and alternative fuels is the goal of the model presented here. The objective of this paper is to define a PHEV model for use in the EcoCAR competition series. E85, gaseous hydrogen, and grid electricity are considered. The powertrain architecture selected is a series plug-in hybrid electric vehicle (SPHEV). The energy for charge sustaining operation is converted from fuel in an auxiliary power unit (APU). Compressed hydrogen gas is converted to electricity via the use of a fuel cell system and boost converter. For E85, the APU is an engine coupled to a generator. The results of modeling the vehicle allow for the comparison of the new architecture to the stock vehicle. In combination with the GREET model developed by Argonne National Lab, the multiple energy sources are compared for well to wheel energy use, petroleum energy use, and greenhouse gas emissions. / Master of Science
2

The standardization of major Well-to-Wheel models : measuring uncertainty on a macro level

El-Houjeiri, Hassan M. January 2011 (has links)
This project concentrated upon the development of the Standardization Transport Model (STM) by assembling the largest possible assessment platform. It combines data from all of the major Well-to-Wheel (WtW) models in the field. The STM was developed for each chain under study by formulating the data in the major databases so that the Well-to-Tank processes covered Feedstock Production, Feedstock Transport, Fuel Production and Fuel Distribution. With the addition of Tank-to-Wheel data, a comprehensive STM was obtained for each chain. For each stage there is a range of values that was characterized by a probability distribution and through the use of Monte Carlo simulation the distribution was sampled and overall values for the total energy consumption, in MJ/km, and total GHG emissions in grams of carbon dioxide equivalent per kilometre (gCO2eq/km) were generated. By statistical means these distributions were compared to assess the risk of debt as well as the likelihood of major savings if they were to be implemented. The scope of the analysis was limited to passenger cars transport and does not include other forms of road transport. Major classic WtW models may account for subjective uncertainty in the input parameters of the model but with a default set of inputs which represents only one database and one set of modelling assumptions and choices. This individualism and determinism in the WtW modelling nowadays explains the significant discrepancies that arise across the results from different models. The level of variation presented poses a major problem in the context of policy making and strategic planning. The generation of the STM rests upon the convection that a synthesis which generates a statistically relevant aggregate of the different WtW results from the different models of the major expert groups would eliminate the present inconsistencies and deliver the reliability required for making robust strategic decisions. Advantage was taken of the richness of the STM outputs to assess the sensitivity of the results and identify the major factors of disagreement within the expert systems. Here the STM presents the largest platform of comparison and the most comprehensive evaluation of the different WtW models in the field. The provision of such a sensitivity analysis was not possible without allowing for variation in the elements of the model as done using the STM. Secondly, the key outputs of the model were compared under the criterion of sustainability from both energy and environmental perspectives. This was done by the synthesis of a first-of-its-kind distribution of the difference between the conventional system and the alternative system for each option under study. The output reflects as complete a population as possible of what may occur in reality in terms of direct impact on sustainability. This method of comparison was not possible without synthesizing an aggregate of possibilities as done using the STM. Thirdly, synergies with the power sector were studied to identify which strategies delay the global reduction in GHG emissions and which are to be preferred from an overall perspective. Here the author lead the transport research community in looking on the global benefits of alternative transport systems, rather than only looking through the window of the transport sector, by redrawing the boundary for the analysis of prospective transport systems. Last and not least, the outcomes of the comparative analyses of the STM results were aggregated into a proposed strategic framework for carbon and energy reduction in passenger cars transport. The strategic framework is placed into perspective by building a set of future scenarios and scaling the effect for the progressive implementation of these scenarios and making a comparison with the business-as-usual forecast. The creation of an energy economy based on hydrogen fuel was found to be a highly questionable objective because electrically driven vehicles are superior with regard to systems that are either nuclear resourced or based on non-biomass renewables. For hydrogen, only the option from waste wood via gasification was found to be very attractive. However because only a minor role for hydrogen is foreseen, it is envisaged that the development of a hydrogen infrastructure would not be feasible. Therefore the use of hydrogen will be constrained to decentral systems or central systems with liquid hydrogen distribution. With regard to cultivated biomass, the sugar ethanol options are the best in terms of land use with sugarcane having the advantage of being economic and available for short-term penetration. The safe implementation of sugar ethanol, which includes avoidance of CO₂ emissions from indirect land use change and low fertilizers use, guarantees significant savings and have a good potential for large CO₂ emissions savings. Generally due to land use limitation cultivated biomass based options cannot be sustained on the long term. Last and not least, the CO2 emissions savings from clean coal technology is questionable without CCS technology and even though with the implementation of CCS no significant savings are certain. On the other hand, besides the transport sector the power sector is another major sector of energy resource consumption and careful consideration of any synergies between the sectors is essential for the completeness of the analysis. The strategy in which the use of alternatives such as NG, nuclear and renewables is not diversified but fed only into the power sector is to be preferred as this avoids possible CO₂ emissions from indirect resource use change, and it also isolates the power market to maintain upstream energy security. Finally, the answer to whether it is still possible to save the World from the disastrous consequences of Global Warming is a preliminary "yes" but requires the development and implementation of a complete technology package including nuclear power which is widely debated at the present.
3

Well-to-wheel greenhouse gas emissions and energy use analysis of hypothetical fleet of electrified vehicles in Canada and the U.S.

Maduro, Miguelangel 01 December 2010 (has links)
The shift to strong hybrid and electrified vehicle architectures engenders controversy and brings about many unanswered questions. It is unclear whether developed markets will have the infrastructure in place to support and successfully implement them. To date, limited effort has been made to comprehend if the energy and transportation solutions that work well for one city or geographic region may extend broadly. A region's capacity to supply a fleet of EVs, or plug-in hybrid vehicles with the required charging infrastructure, does not necessarily make such vehicle architectures an optimal solution. In this study, a mix of technologies ranging from HEV to PHEV and EREV through to Battery Electric Vehicles were analyzed and set in three Canadian Provinces and 3 U.S. Regions for the year 2020. Government agency developed environmental software tools were used to estimate greenhouse gas emissions and energy use. Projected vehicle technology shares were employed to estimate regional environmental implications. Alternative vehicle technologies and fuels are recommended for each region based on local power generation schemes. / UOIT
4

The role of methane and hydrogen in a fossil-free Swedish transport sector

Larsson, Mårten January 2015 (has links)
Drastic reductions of greenhouse gas emissions are required to limit the severe risks associated with a changing climate. One measure is to disrupt the fossil-fuel dependency in the transport sector, but it appears difficult and costly in comparison to other measures. Vehicles and fuels are available, but no single alternative can replace petrol and diesel in all parts of the transport system. None of them are ideal regarding all of the following aspects: vehicle performance, fuel production potential, sustainability, infrastructure, technology development and economy. Instead, several fuels are needed. In this thesis, the aim is to investigate the role of methane and hydrogen in a fossil- free vehicle fleet in Sweden, and compare them with other fuels in terms of well-to-wheel energy efficiency and economy. Processes for producing methane from biomass, waste streams from pulp mills and electricity are studied with techno-economic methods. Furthermore, well-to-wheel studies and scenarios are used to investigate the fuel chains and the interaction with the energy and transport systems. Effects of policy instruments on the development of biogas in the Swedish transport sector are also analysed and policy instruments are suggested to increase the use of methane and to introduce hydrogen and fuel cell electric vehicles. The results reveal that tax exemptions and investment support have been and will continue to be important policy instruments, but that effective policy instruments are needed to develop fuelling infrastructure and to support alternative vehicles. Electricity will be an important transport fuel for several reasons; the electric powertrain enables high energy efficiency and electricity can be produced from various renewable energy sources. Nevertheless, other fuels will be needed as complements to electricity. The results reveal that methane and hydrogen and associated vehicles may be necessary to reach a fossil-free vehicle fleet in Sweden. These fuels have several advantages: -        The function of the vehicles resembles conventional vehicles but with lower local and global emissions. -        Methane is a well proven as a transport fuel and hydrogen infrastructure and FCEVs, are commercial or close to commercialisation. -        They enable high well-to-wheel energy efficiency. -        They can be produced from renewable electricity and act as energy storage. / <p>QC 20150929</p>
5

Modeling and real-time optimal energy management for hybrid and plug-in hybrid electric vehicles

Dong, Jian 15 February 2017 (has links)
Today, hybrid electric propulsion technology provides a promising and practical solution for improving vehicle performance, increasing energy efficiency, and reducing harmful emissions, due to the additional flexibility that the technology has provided in the optimal power control and energy management, which are the keys to its success. In this work, a systematic approach for real-time optimal energy management of hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) has been introduced and validated through two HEV/PHEV case studies. Firstly, a new analytical model of the optimal control problem for the Toyota Prius HEV with both offline and real-time solutions was presented and validated through Hardware-in-Loop (HIL) real-time simulation. Secondly, the new online or real-time optimal control algorithm was extended to a multi-regime PHEV by modifying the optimal control objective function and introducing a real-time implementable control algorithm with an adaptive coefficient tuning strategy. A number of practical issues in vehicle control, including drivability, controller integration, etc. are also investigated. The new algorithm was also validated on various driving cycles using both Model-in-Loop (MIL) and HIL environment. This research better utilizes the energy efficiency and emissions reduction potentials of hybrid electric powertrain systems, and forms the foundation for development of the next generation HEVs and PHEVs. / Graduate / laindeece@gmail.com
6

THE POLICY-TECHNOLOGY NEXUS FOR MITGATING PASSENGER ON-ROAD TRANSPORTATION GHG EMISSIONS: E-BUS, E-RIDE-SHARE, OR OTHER ALTERNATIVES / ASSESSMENT OF TRANSPORTATION GHG MITGATING SOLUTIONS

Soukhov, Anastasi January 2021 (has links)
The passenger transportation sector is notoriously difficult to decarbonize. In this thesis, two distinct and novel methodologies to estimate the environmental impact of alternative and conventional transportation technologies are developed. In Chapter 2, a provincial fleet policy-driven linear programming model is developed to minimize the cost of three passenger vehicle electrification policies in Ontario under a 30% GHG reduction target by 2030. Provincial life-cycle emissions and total-cost-of-ownership associated with policy allocation is estimated. The results highlight that electrification of on-road passenger transportation will not be sufficient to meet the 30% reduction target despite Ontario's low-carbon electricity grid. Instead, reductions of between 24% to 26% are forecasted at an annual cost (for ten years) of between CAD 0.29 to 0.3 billion annually indicating that additional policies are necessary to realize a 30% reduction target. In Chapter 3, a trip-level vehicle framework is developed to determine under what operating conditions transit buses and passenger cars will be environmentally beneficial across the dimensions of technology, service mode, and power source pathway. The well-to-wheel energy consumption and GHG emissions are simulated for over 450 operating scenarios. Emissions are then normalized through passenger-trip emission thresholds to facilitate equivalent comparison across all dimensions. The results indicate that the most beneficial solution are fuel-cell electric car-share, battery electric car-share, and battery electric bus all powered by low-carbon intensity power sources at average occupancy (7.9-19.7 gCO2e passenger-service-mode-trip-km-travelled-1). Furthermore, transit bus technologies have the potential to reduce up to 2.3 times more GHG per passenger-trip than comparable ride-share passenger cars at average occupancies. The results of Chapter 2 and 3 highlight that technology alone may not be sufficient to achieve significant GHG reductions; policy which leverage local operating data and target GHG reduction associated with passenger-trips are critical to informing under what conditions a mobility solution is environmentally beneficial. / Thesis / Master of Civil Engineering (MCE) / There is a dire need to evaluate the effectiveness of transportation GHG mitigation policies as alternative mobility solutions are being adopted and the pressure to respond to climate change intensifies. This work evaluates the effectiveness of policy optimization and vehicle-level simulation techniques to inform GHG mitigation decision-making. A two-step approach is adopted herein. At the strategic level, a cost optimization model for passenger vehicle electrification policies in Ontario is calibrated to identify the optimal allocation of provincial policy to achieve a 30% GHG reduction by 2030. Next, a micro level focuses on the energy consumption of eight vehicle technologies over 450 operational scenarios is simulated and trip-level passenger emissions are estimated to reveal the environmentally beneficial mobility option, corresponding passenger thresholds, and extent of variability associated with local operating conditions. Overall, optimization and trip-level vehicle simulation can be used to demystify optimal decision-making related to mobility solutions.
7

External costs of the Dieselgate – Peccadillo or substantial consequences?

Baumgärtner, Frank, Letmathe, Peter 15 August 2022 (has links)
The Dieselgate has changed the public view of diesel powertrains and local authorities have issued first driving bans on diesel cars in Germany. Nevertheless, a systematic calculation of the external costs of the Dieselgate considering different car models and a variety of emissions has not yet been conducted. We compare the results, which reflect emissions under test bench conditions, with those of diesel cars under the assumption that NOX emissions reflect realistic driving behavior. We find that diesel cars with idealized emissions are superior to petrol cars with regard to external costs and that electric cars have only partially lower external costs than diesel cars. However, when realistic driving behaviors are considered, diesel engines constitute the worst powertrain in all cases. Our results show that the Dieselgate has led to substantially higher external costs than cars which would comply with environmental regulations under realistic driving conditions.
8

Electricity load estimation and management for plug-in vehicle recharging on a national scale prior to the development of third party monitoring and control mechanisms

Parry, Emily January 2014 (has links)
In accordance with the main aim of the study, a widely accessible, modifiable tool was created for parties interested in maintaining the national electricity supply network and parties interested in informing policy on plug-in vehicle adoption schemes and recharging behaviour control. The Parry Tool enables the user to incorporate present limits to plug-in vehicle recharging demand scheduling as imposed by the state of present technology (no third party mechanism for monitoring and control of recharging), present human travel behaviour needs and existing patterns in electricity usage; into the investigation of the impacts of recharging demand impacts and the design of mitigation measures for deflecting (parrying) worst case scenarios. The second aim of the project was to demonstrate the application of the Parry Tool. The multidisciplinary/interdisciplinary information gathered by the Parry Tool was used to produce national demand profiles for plug-in vehicle recharging demand, calculated using socioeconomic and travel behaviour-estimated population sizes for plug-in eligible vehicles and vehicle usage patterns, which were added to existing national electricity demand for a chosen test week – this was the first scenario subsequently tested. The information gathered by the Parry Tool was then used to inform the design of two demand management methods for plug-in vehicle recharging: Recharging Regimes and weekly recharging load-shifting – these were the second and third scenarios subsequently tested. Unmitigated simultaneous recharging demand in scenario 1 (all vehicles assumed to recharge at home upon arrival home every day) severely exacerbated peak demand, raising it by 20% above the highest peak in existing demand for the year 2009 over half an hour from 58,554 MW to 70,012 MW – a challenge to the generation sector. This increased the difference between daily demand minima and maxima and made the new total demand have sharper peaks – a challenge for grid regulators. Recharging Regimes in scenario 2 split the estimated national plug-in vehicle populations into groups of different sizes that started recharging at different times of the day, with the word ‘regime’ being applied because the spread of start times changed over the course of the test week from workdays to weekend. This avoided exacerbation of the peak and reduced the difference between daily demand minima and maxima by raising minima, providing a load-levelling service. Scenario 3 embellished the Recharging Regimes with workday-to-weekend recharging load-shifting that therefore took better advantage of the often overlooked weekly pattern in existing demand (demand being higher on workdays than weekends), by allowing partial recharging of a segment of the plug-in vehicle population. Limited consideration of the impact of changing vehicle energy usage (for which distance travelled was assumed to proxy in this study) showed that the more vehicles used their batteries during the day, the better the levelling effect offered by Recharging Regimes. Greater utilisation of battery capacity each day, however, can also be assumed to lessen the potential for workday-to-weekend load levelling, because load-shifting depends upon vehicles being able to partially recharge or defer recharging to later days and still meet their travel needs plus keep a reserve State Of Charge (SOC) for emergency and other unplanned travel. Whilst altering vehicle energy usage did not change the finding that unmitigated simultaneous recharging exacerbated existing peak demand, it was noted that when limited mileage variation was considered this sharpened the profile of total demand – the rise and fall of the new peak far steeper than that of the original peak in existing demand. The Parry Tool combines a series of integrated methods, several of which are new contributions to the field that use UK data archives but may potentially be adapted by researchers looking at energy issues in other nations. It presents a novel fossil-fuel based justification for targeting road transport – acknowledging energy use of fossil fuel as the originator of many global and local problems, the importance of non-energy use of petroleum products and subsequent conflicts of interest for use, and a fossil fuel dependency based well-to-wheel assessment for UK road transport for the two energy pathways: electricity and petroleum products. It presents a method for the recalculation and ranking of top energy use/users using national energy use statistics that better highlights the importance of the electricity industry. It also presents the first publicly documented method for the direct consultation and extraction of vehicle-focused statistics from the people-focused National Travel Survey database, including a travel behaviour and household income-based assessment of plug-in vehicle eligibility, used to scale up to national estimates for battery electric and plug-in electric hybrid vehicle (BEV and PHEV) national population sizes. The work presented here is meant to allow the reader to perceive the potential benefits of using several resources in combination. It details the Parry Tool, a framework for doing so, and where necessary provides methods for data analysis to suit. It should however be noted that methods were kept as simple as possible so as to be easily followed by non-specialists and researchers entering the field from other disciplines. Methods are also predominantly data-exploratory in nature: strong conclusions therefore should not be drawn. Rather, the work here should be seen as a guideline for future work that may more rigorously study these combined topics and the impacts they may have upon plug-in vehicle ownership, usage behaviour, impacts of recharging upon the national network and the design of mitigation measures to cope with this new demand.
9

Analysis of Alternative Fuels in Automotive Powertrains

Gunnarsson, Andreas January 2009 (has links)
<p>The awareness of the effect emissions have on the environment and climate has risen in the last decades. This has caused strict regulations of greenhouse gas emissions. Greenhouse gases cause global warming which may have devastating environmental effects. Most of the fuels commercially available today are fossil fuels. There are two major effects of using fuels with fossil origin; the source will eventually drain and the usage results in an increase of greenhouse gases in the atmosphere. Fuels that are created from a renewable feedstock are often referred to as alternative fuels and under ideal conditions they are greenhouse gas neutral, meaning that the same amount of greenhouse gases is released during combustion as the source of the fuel have absorbed during its growth period. This evaluation method is known as a well-to-wheel analysis which besides emissions also evaluates energy efficiencies during both the production and the combustion phases.</p><p>By evaluating results of well-to-wheel analyses along with fuel properties and engine concept characteristics, this report presents which driving scenario that is suitable for different powertrain configurations. For example, vehicles operating in high populated areas, as cities, have a driving scenario that includes low velocities and multiple stops while vehicles in low populated areas often travel long distances in higher speeds. This implies that different powertrains are suitable in different regions. By matching favorable properties of a certain powertrain to the properties important to the actual driving scenario this report evolves a fuel infrastructure that is suitable in Sweden.</p>
10

Analysis of Alternative Fuels in Automotive Powertrains

Gunnarsson, Andreas January 2009 (has links)
The awareness of the effect emissions have on the environment and climate has risen in the last decades. This has caused strict regulations of greenhouse gas emissions. Greenhouse gases cause global warming which may have devastating environmental effects. Most of the fuels commercially available today are fossil fuels. There are two major effects of using fuels with fossil origin; the source will eventually drain and the usage results in an increase of greenhouse gases in the atmosphere. Fuels that are created from a renewable feedstock are often referred to as alternative fuels and under ideal conditions they are greenhouse gas neutral, meaning that the same amount of greenhouse gases is released during combustion as the source of the fuel have absorbed during its growth period. This evaluation method is known as a well-to-wheel analysis which besides emissions also evaluates energy efficiencies during both the production and the combustion phases. By evaluating results of well-to-wheel analyses along with fuel properties and engine concept characteristics, this report presents which driving scenario that is suitable for different powertrain configurations. For example, vehicles operating in high populated areas, as cities, have a driving scenario that includes low velocities and multiple stops while vehicles in low populated areas often travel long distances in higher speeds. This implies that different powertrains are suitable in different regions. By matching favorable properties of a certain powertrain to the properties important to the actual driving scenario this report evolves a fuel infrastructure that is suitable in Sweden.

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