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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.
51

Methods for advancing automobile research with energy-use simulation

Geller, Benjamin M. 22 October 2014 (has links)
<p> Personal transportation has a large and increasing impact on people, society, and the environment globally. Computational energy-use simulation is becoming a key tool for automotive research and development in designing efficient, sustainable, and consumer acceptable personal transportation systems. Historically, research in personal transportation system design has not been held to the same standards as other scientific fields in that classical experimental design concepts have not been followed in practice. Instead, transportation researchers have built their analyses around available automotive simulation tools, but conventional automotive simulation tools are not well-equipped to answer system-level questions regarding transportation system design, environmental impacts, and policy analysis. </p><p> The proposed work in this dissertation aims to provide a means for applying more relevant simulation and analysis tools to these system-level research questions. First, I describe the objectives and requirements of vehicle energy-use simulation and design research, and the tools that have been used to execute this research. Next this dissertation develops a toolset for constructing system-level design studies with structured investigations and defensible hypothesis testing. The roles of experimental design, optimization, concept of operations, decision support, and uncertainty are defined for the application of automotive energy simulation and system design studies. </p><p> The results of this work are a suite of computational design and analysis tools that can serve to hold automotive research to the same standard as other scientific fields while providing the tools necessary to complete defensible and objective design studies.</p>
52

Evaluation of power-assist hydraulic and electric hybrids for medium- and heavy-duty vehicle applications

Wagner, Justin Taylor 23 October 2014 (has links)
<p> Under pressure from rising fuel costs, emissions constraints, and new government regulations on medium- and heavy-duty vehicles, hybrid technologies for these classes of vehicles are becoming more prevalent. A variety of technologies have been proposed to meet these requirements including power-assist hybrid electric and hybrid hydraulic systems. Although there has been great discussion about the benefits surrounding each of the technologies individually, no direct comparisons are available on the basis of economics and fuel economy. This study focuses on comparing these power-assist technologies on these bases as well as determines the ability of these technologies to fulfill the newly adopted fuel economy regulations. </p><p> In order to accomplish this goal, three computational models of vehicle dynamics, thermal behavior and fuel economy were created and validated to simulate the conventional vehicle and hydraulic and electric hybrids. These models were simulated over the Heavy-Duty Urban Dynamometer Driving Schedule, the HTUF Class 4 Parcel Delivery Cycle, and the Orange County Bus cycle. These drive cycles were chosen on their ability to characterize the variety of operating conditions observed in medium- and heavy-duty vehicles. Using these models, cross technology comparisons were constructed comparing commercially available systems, systems with a fixed mass, and systems with a fixed incremental cost. </p><p> The results of the commercially available systems showed that the Azure Dynamics HEV provided greater fuel economy improvement than the Lightning Hybrids HHV for drive cycle kinetic intensities less than 3.19 miles<sup> -1</sup>. Although this system showed a cost of fuel savings over the HHV, it was seen that the incremental cost of the HEV exceeded the cost of fuel savings over the HHV. The fixed mass comparison case, which compared vehicles with equal cargo carrying utility, showed similar results to that of the commercially available case. Although the increase in incremental cost for the varying HEV systems designed for the fixed mass case correlated to an improvement in fuel savings, the cost associated with the systems surpassed the savings seen. Lastly, the fixed cost case provided results which were also similar to the commercially available case. Due to the fixed system cost, it was seen that for these systems, the fuel economy benefits and associated cost showed the greatest benefits for the HEV. </p><p> This study concluded that given the evaluation, the HEV was the only power-assist hybrid technology which could fulfill the regulated fuel economy improvement of 15%. Although the HEV was the only technology which could fulfill the requirements, the HHV showed an improvement upwards of 7% greater than the HEV for the Orange County Bus Drive Cycle.</p>
53

Reverse Logistics in Automotive Indusrty : A multiple case study in automotive industry

Mao, Zhaoanjian, Jin, Yang January 2014 (has links)
No description available.
54

Technology and human resource strategy in their national context

Harding, Rebecca Adrienne January 1991 (has links)
No description available.
55

A study of the effects of current and proposed restraint concepts on the child occupants of vehicles

Paton, Ian Patrick January 2000 (has links)
This research evaluates the performance of automotive child restraint systems (CRS) that conform to international proposals for a universal restraint concept to be adopted by both restraint and vehicle manufacturers. The concept is known as Isofix (International Standards Organisation FIXing), and is intended to ensure optimum compatibility and coupling between vehicle and CRS. In order to quantify the benefits of the proposed Isofix concept it has been necessary to establish the performance limits and benefits offered by current commercially available adult belt retained CRS. A considerable body of knowledge existed on the performance and limitations of the then current CRS. However, during 1995 a significant amendment was introduced affecting ECE R44, the compliance standards applicable to CRS in Europe to which most rnanufacturers require their products to conform (separate national standards also exist). In 1995 amendment 03 was added to ECE R44 and became a catalyst for considerable development activity by manufacturers of child restraints, that resulted in new or revised product ranges. These new products, in particular forward facing Group 1 (9-15 kg) child restraints have significantly improved dynamic performance in frontal impacts, notably in modern vehicles whose seat belt anchorage positions have been optimised for restraint of adults, but are commonly less effective in restraining framed CRS. It was important therefore to re-assess existing systems as the baseline for a realistic evaluation of the proposed Isofix concepts (chapter 10). It was evident that, of the different Isofix concepts being proposed, no overall evaluation of their relative performance had, to that date, been undertaken. A programme involving the design and manufacture of not only suitable test equipment but, in a number of cases, prototype devices, was undertaken. The resulting data have formed the basis of input to the ISO Working Group 1, the body responsible for the evolution of the Isofix concept. This programme also highlighted a number of shortfalls in the proposed concepts. The major results of this test programme have been published at international level, and were used to inform the Isofix discussions. During the programme of comparative evaluation of not only the Isofix but the current belt retained devices, it became clear to the writer that in a frontal impact the orientation of the occupant with respect to the direction of travel had significance. A literature survey produced evidence of minimal research in this area. Hence it was decided by the writer to include a programme of parametric tests to investigate the significance of occupant orientation, given that commercially available CRS often include a feature to vary the recline angle of the seat. The Isofix set-up was particularly suitable for this exercise in that it eliminated many of the variables associated with belt retained devices. The results of this work have been published at intemationallevel. A review of the available accident data indicates that side impacts are potentially more life threatening than the more common frontal impacts due to the proximity of the occupant to an intruding vehicle or object. However, current European certification standards do not require the evaluation of CRS in a side impact. This is considered to be an area where improvements, particularly aided by an Isofix type attachment concept, can be made. Therefore the final area of research undertaken by the writer was to develop and propose a test to evaluate CRS in a realistic side impact scenario. This involved the simulation of not only the acceleration imparted to the target vehicle occupant but in addition the intrusion component. This work, which again has been presented at international level, contributed towards a proposal to amend the European certification standard for CRS to include a side impact evaluation. This thesis commences with a review of the accident data currently available, and looks at how the physiological and anatomical properties of the child, vehicle design, and the inherent potential for misuse and mis-installation of the current generation of CRS, impact upon child safety. This is followed by an overview of the lsofix proposal before the results of the writer's detailed testing of both current belt retained and proposed Isofix CRS concepts (chapters 10 and 11) are reported. The subsequent chapters (12 and 13) detail the results of the writer's investigation into CRS orientation in a frontal impact and the development of a representative side impact test, based on a single sled, for inclusion in the European certification procedure. The document concludes with discussion and conclusions relating to the future of CRS design and evaluation. The major findings of this research were: • contrary to initial expectations, significant CRS recline angle in a forward facing device has been proven to be undesirable; • Isofix CRS with rigid lower anchors have been shown to be beneficial, particularly in side impacts, their efficacy in a forward impact being compromised by rotation in devices that do not incorporate an anti-rotation device; • a side impact test has been developed which more accurately represents the input to a CRS seen in a rear vehicle incident. Such a test is not only desirable but essential to drive CRS manufacturers into improving side impact protection for occupants.
56

The development of African road transport in western Nigeria, 1919-1939 /

Gutkind, Alice January 1977 (has links)
No description available.
57

Travel characteristics of urban freight vehicles and their effects on air quality

Protopapas, Annie, January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Tennessee, Knoxville, 2004. / Vita. Includes bibliographical references. Includes bibliographical references (p. 48-52).
58

Low-temperature combustion in a small-bore high-speed direct injection optically accessible diesel engine /

Fang, Tiegang, January 2007 (has links)
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4777. Adviser: Chia-Fon F. Lee. Includes bibliographical references (leaves 434-447) Available on microfilm from Pro Quest Information and Learning.
59

Investigation of clean diesel combustion with oxygenated fuels in a constant-volume combustion chamber using forward illumination light extinction technique /

Xu, Yi, January 2006 (has links)
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4792. Adviser: Chia-Fon Lee. Includes bibliographical references (leaves 196-205) Available on microfilm from Pro Quest Information and Learning.
60

Transportation problems faced after big earthquakes /

Manchikalapudi, Lakshminarayana, January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 126-127). Also available via the Internet.

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