No description available.

by Luk Shiu-fai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 234-240). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / Electronic engine control systems utilise tables, or maps, of data to determine the set-points of the various actuators on the engine and to calculate the values of variables that cannot be directly measured. To ensure accurate control of the engine processes the values in these maps have to be accurately calibrated for the particular engine being controlled. Due to the complex interaction of the various systems in the engine it is becoming more and more difficult for human calibration engineers to be able to take all the effects of changes to a particular parameter into account. This problem is made worse by increasingly strict emissions regulations and performance demands from the customer. The process of calibrating the maps in an Electronic Control Unit (ECU) is also very resource intensive since it involves taking a test engine installed in an engine test cell to every operating point on the various maps and adjusting the map values until the desired response is achieved. The aim of this project was to develop a solution to this problem in the form of a simulation based calibration system. The proposed system would use an accurate model of the engine to simulate the effect of various map values on the engine response. This data would then be used to find the map values that would enable the engine to deliver a desired torque curve. In the case where it is not practical to use engine simulation the system would be able to process a database created by testing an actual engine. This testing could also be automated. To achieve this aim the AutoCal program was created. This program can manage a commercial engine simulation code to create a database of the effect of various calibration values on the engine response. It can then evaluate the created database subject to user defined operating constraints and find calibration values that will deliver a desired torque curve. It can also be used to evaluate and process databases created by engine testing. To provide the data required for the development and testing of the AutoCal program, a naturally-aspirated engine was turbo-charged and tested at various operating points. The resulting data was used to calibrate and validate a model of the engine created and simulated with the WAVE software package from Ricardo. The project was focused on finding calibration values for the maps used to control the turbo-charger wastegate and ignition timing of the test engine. Work was limited to the full load operating region and fixed Air/Fuel Ratio (AFR) values were used. The project showed that simulation based calibration can be used to calibrate control system maps once an accurate model of the engine being controlled has been created. Very useful insight was gained into the process of building, testing and modelling a turbo-charged internal-combustion engine and calibrating modern electronic engine control systems. The end result is a useful engineering tool with the following functions: ² Automatically simulating the effect of various control inputs on engine performance. ² Determining the correct calibration settings to deliver the desired performance subject to user-definable constraints. This can be done using results from simulation or physical engine testing in the case of simulation tools not being available. ² Providing the data required when calibrating the engine model used during simulation by processing and displaying the outputs of the simulation program compared to test data. ² Plotting any test or simulation results in a format configured by the user. Using this tool facilitates a more structured and less resource intensive approach to engine control system calibration. / Imported from http://etd.sun.ac.za April 2010. / np2010

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Transport Policy and Planning / Master / Master of Arts

No description available.

The impacts of emissions sources of carbon monoxide and particulate matter pollution levels for projected level conformity assessment and National Environmental Policy Act (NEPA) analyses are usually estimated through computer-aided models. Because of the involvement and interaction of a large number of variables that affect formation of CO and PM hot spots, exhaustive impact assessment studies can be time consuming. This is especially true for complex urban projects consisting of numerous roadways whose potential CO and PM impacts on surrounding neighborhoods must be disclosed. A highway project may consist of hundreds of roadway links, therefore undertaking project level conformity analysis without screening tools can be computationally resource intensive. CALINE4, a line source emission modeling tool, is used to predict downwind CO and PM concentrations for various receptors to generate a learning dataset for development of screening rules. This research has developed statistical screening criteria based on Classification and Regression Tree modeling that can be used to eliminate those links from the CALINE4 analysis whose contribution of pollutant concentration to a particular receptor site are insignificant. For the purpose of this study, any link that contributes a concentration of 0 ppm of CO or 0 µg/m3 of PM to a particular receptor site is termed insignificant for the corresponding pollutant. The model uses seven predictor variables, namely wind speed, wind directional variability, linear emission flux, link length and receptor polar coordinates. Response vector has two classes of pollutant concentrations namely significant and insignificant which are obtained by conversion of numerical values of pollutant concentration according to above mentioned criterion, thereby converting a regression problem into categorical or classification problem. The developed rules based on constructed model were validated through test samples and can be applied to future dataset to classify and screen out the insignificant links in highway planning analyses. The screening tool also allows analysts to prepare gridded pollution concentration predictions for use in environmental justice analyses.

Orientador: Auteliano Antunes dos Santos Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T15:41:43Z (GMT). No. of bitstreams: 1 Idehara_AnneliseYuiko_M.pdf: 2161496 bytes, checksum: 55c604cc3cef545df951f0fbb8f2af19 (MD5) Previous issue date: 2009 / Resumo: Este trabalho tem como objetivo a análise do fenômeno de vibração na direção longitudinal de árvore de manivelas em motores de combustão interna, o cálculo de esforços sobre o mancal e o cálculo dos deslocamentos causados pela dinâmica do virabrequim. Essa vibração é apontada como uma das causas de desgaste precoce dos componentes acoplados ao virabrequim e do próprio componente. Reduzir essa vibração contribui para o aumento da vida útil e eficiência. A formulação proposta para estudo da dinâmica da estrutura é o modelo de múltiplos graus de liberdade com massas e inércias concentradas. Para o cálculo dos esforços de reação dos mancais, a equação de Reynolds é resolvida por diferenças finitas. Além disso, o programa comercial Excite (AVL) é utilizado para aferir resultados e fazer comparações. Os resultados são apresentados para diferentes condições de operação em um virabrequim comercial. Analisa-se de forma simples o efeito da redução de massa de 5% e de 10%. Por fim, conclui-se que a árvore de manivelas simulada não apresenta desgaste por contato metal-metal. / Abstract: This paper aims to analyze the phenomenon of vibration in the longitudinal direction of the crankshaft in internal combustion engines, the calculation of loads on the bearing and the calculation of displacements caused by the dynamics of the crankshaft. This vibration is identified as a cause of premature wear of the components coupled to the crankshaft and the component itself. Reduction in this vibration contributes to increased efficiency and life service time. The proposed formulation to study the dynamics of the structure is the model of multiple degrees of freedom with concentrated masses and inertias. The Reynolds equation is solved by Finite Differences Method to calculate the supported load of the bearing. In addition, the commercial program Excite (AVL) is used to evaluete results and make comparison. The results are presented for different operating conditions in a commercial crankshaft. A simple analysis of a crankshaft mass reduction of 5% and 10% is done. Finally, a conclusion that the crankshaft does not present a metal-metal contact is done. / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Traffic-related air pollution harms health, so whilst it would be advantageous to improve air quality, the socioeconomic impact of air pollution mitigation in Scotland is not fully understood. Evidence from research literature, current regulatory and policy directives and a socioeconomic analysis are required to assess the true health impact. This thesis presents the first health and socioeconomic analysis of traffic-related air pollution and health for Scotland. A critique of the literature was undertaken to determine the evidence base and the strength of evidence in terms of association and causation, between air pollution and ill health. The evidence was subsequently applied in epidemiological studies of Scottish residents, to assess the actual impact on health in Scotland. The perception of barriers and incentives for change were investigated to understand behavioural influences. Recent policy development in Scotland was reviewed, and a socioeconomic analysis of a proposed air pollution strategy in Scotland, was undertaken. The evidence from 30 cohort studies and nine literature reviews demonstrated a link between poor air quality, mortality and respiratory ill health, but the results for other health conditions were inconsistent. The links were associative rather than causal and therefore might be attributable to other factors other than air pollution. Furthermore, epidemiological studies on Scottish populations did not show health effects from traffic-related air pollution. The socioeconomic analysis suggested that an initial investment of between £27m and £44m to introduce Low Emission Zones (LEZ), and an effective active travel programme, might result in a saving of £38m in terms of Years of Life Lost (YLL) and reduction in sickness absence. It is unlikely that the Clean Air For Scotland Strategy will deliver improved air quality and health without substantial investment, better alignment of planning, and a greater public engagement to support public and active transport options.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning