Mass transportation systems, specifically bus systems, are a key element of the national transportation network. Buses are one of the safest forms of transportation; nonetheless, bus crashes resulting in occupant injuries and fatalities do occur. According to Traffic Safety Facts reports from 1999 to 2003, an average of 40 fatalities and 18,430 injuries of bus occupants have occurred per year, with side impact accounting for 14 % according to type of impact and by initial point of impact it accounts for 36%. A full scale crash test is considered the most reliable source of information regarding structural integrity and safety of motor vehicles. However, the high cost of such tests and difficulties in collecting data has resulted in an increasing interest in the analytical and computational methods of evaluation. With the advancement in computer simulations, full finite element validated vehicle models are being analyzed for different impact scenarios to predict vehicle behavior and occupant response. This thesis research work presents the procedure for development of a finite element (FE) model of a mass transit bus and the results of its crashworthiness and structural integrity analysis. The finite element model is developed by extracting mid-surface from solid cad model. This model is a detailed model with all parts. All parts are connected using different multi point constraints and special links with failure to model actual types of structural connections such as bolts and spot welds. LS-DYNA non-linear, explicit, 3-D, dynamic FE computer code was used to simulate behavior of the transit bus under different side impact scenarios. A parametric study is done to study structural response of transit bus when impacted by vehicles of different masses, sizes and shapes. A multibody analysis is done to study occupant response to different side impact crash conditions. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 129-137).

Em vigência desde Janeiro de 2012, a regulamentação Proconve P7 para veículos comerciais pesados exige que a demonstração de emissões de poluentes do motor seja realizada no ciclo de teste transiente europeu (ETC), desenvolvido de acordo com perfil de condução tipicamente europeu e assim pouco representativo de diversas situações de tráfego no Brasil. Especialmente quanto a aplicações de ônibus urbanos, altamente dinâmicas e submetidas a perfis de baixa velocidade e média carga, não é possível correlacionar plenamente o funcionamento do motor e seus sistemas de controle de emissões baseando-se apenas neste ciclo. Com essa motivação, o principal objetivo deste estudo é desenvolver ciclos de teste compactos para banco de provas de chassis e de motores que representem as condições reais de condução de ônibus urbanos da cidade de São Paulo. Estes ciclos de teste específicos possibilitam avaliações mais precisas não apenas das emissões de poluentes, mas também do consumo de combustível, além de proporcionarem melhor compreensão do real desempenho de motores e novas tecnologias dos sistemas de propulsão usados em frotas de ônibus urbanos no Brasil. A metodologia aplicada para construção dos ciclos utiliza o conceito de potência específica veicular (VSP), variável que apresenta alta correlação com emissões de poluentes e consumo de combustível e é calculada a partir de dados coletados em condições reais de condução de ônibus (velocidade, aceleração e inclinação das vias). A seleção dos veículos e linhas para realização das aquisições de dados considera tanto as especificações de trem-de-força e de chassis disponíveis na frota, como também os índices operacionais e a topografia dos trajetos como métodos para determinação de linhas com perfil operacional mais representativo. Como resultado do estudo foram propostos cinco ciclos de teste, um para cada tipo de ônibus selecionado (miniônibus, midiônibus, básico, padron e articulado), e as análises comparativas com o ciclo ETC quanto ao comportamento do motor mostram claramente a falta de representatividade do ciclo europeu adotado pela regulamentação brasileira. / Since January 2012, the Proconve P7 regulation is mandatory for heavy duty commercial vehicles requiring that the demonstration of pollutant gases emissions must be carried out by submitting the engine to the European transient test cycle (ETC), which has been developed according to European driving patterns and therefore is not representative of several driving situations in Brazil. Particularly for driving patterns of urban buses, which are highly dynamic with low vehicle speed and medium load profiles, it is not possible to fully correlate the operating conditions of the engine and its emission control systems based only on this test cycle. With this motivation, the main objective of this study is to develop compact test cycles for use in both chassis and engine test benches that represent the actual driving pattern of transit buses in São Paulo city. These specific test cycles may allow more accurate assessment of pollutant gases emissions and fuel consumption, as well as provide a better understanding concerning the real performance of engines and new propulsion technologies used in urban bus fleets in Brazil. The methodology used for construction of the cycles is based on the concept of vehicle specific power (VSP), a variable that is highly correlated with pollutant emissions and fuel consumption and is calculated from data collected under real-world driving conditions (vehicle speed, acceleration and road grade). The selection of the buses and routes for the on-board data collection considers the specifications of powertrain and chassis that are available in the bus fleet of São Paulo\'s public transportation system, operational indexes and route topography as a method for determining the bus routes with a more representative operational pattern. As the result of this study five test cycles were proposed, one for each bus type (minibus, midibus, basic, padron and articulated), and an analysis of the engine\'s operating behavior in comparison to the ETC cycle clearly shows the lack of representativeness of the European cycle adopted by the Brazilian regulation.

<div>Plug-in hybrid electric vehicles (PHEVs) are being considered as an alternative to conventional medium-duty (MD) and heavy-duty (HD) commercial vehicles to reduce fuel consumption and tailpipe emissions. Lithium ion batteries, which are used in PHEVs due to their high energy density, are expensive. The battery contributes significantly towards the life-cycle cost of MD/HD PHEVs, as these vehicles, due to high mass and aggressive battery usage, require multiple battery replacements over their lifetime. Smaller batteries increase the fuel consumption and need more replacements, while bigger batteries increase the initial system cost. Powertrain design from a life-cycle cost perspective is required to explore this trade-off and maximize the economic gains obtained from PHEVs. </div><div><br></div><div>Powertrain design entails component sizing, control strategy selection as well as architecture selection. Different powertrain designs yield different lifetime economic gains. A variety of applications exist for MD/HD vehicles, which differ in their ways of powertrain usage, due to variations in required acceleration, available braking, and average and maximum speeds. Therefore, different powertrain designs are needed depending on the application and usage scenario. The powertrain design space needs to be explored, and solutions that maximize the economic gains within the specified constraints need to be chosen.</div><div><br></div><div>This dissertation compares the economic viability of two PHEV applications (MD Truck and HD Transit Bus), with options of series and parallel hybrid architectures, over multiple drivecycles, for four economic scenarios (years 2015, 2020, 2025 and 2030). It is shown that hybridizing the transit bus achieves payback sooner than hybridizing the truck. Further, the results for the transit bus application, over the Manhattan drivecycle, show that implementation of the parallel architecture is economically viable in the 2015(present) scenario, while the series architecture becomes viable in 2020, due to significantly lower initial costs involved in the parallel architecture.</div><div><br></div><div>A methodology to select a solution out of the explored design space that maximizes the economic gains is demonstrated. Variations in the economic and vehicle usage conditions for which this solution is designed, can be expected. It is therefore necessary to check the robustness of this solution to change in external factors such as vehicle mass, annual vehicle miles travelled (AVMT), component and fuel costs. It is shown that the economic gains are affected by the battery cost, fuel cost, AVMT and vehicle mass, while the number of battery replacements are affected by AVMT and vehicle mass. </div><div><br></div><div>A probability-based approach is demonstrated to obtain confidence in the economic and battery life predictions. Specifically, probability-based variations are provided to variables such as miles traveled between recharge, recharge C-rate and battery temperature. It is shown that battery life is affected the most by battery temperature.</div><div><br></div><div>A battery heating/cooling system is required to maintain constant battery temperature of operation during all seasons, but these systems incur additional fuel costs. A framework that utilizes just the Coefficient of Performance (COP) of the heating/cooling system to calculate the excess fuel cost is proposed and demonstrated. An increase of 0.9-1.8\% in fuel consumption is shown, depending on the drivecycle and ambient temperature.</div><div><br></div><div>Further, the well-to-wheel (WTW) fuel-cycle emissions from conventional and PHEV transit buses operating in Indiana and California are assessed using the ``Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation'' (GREET) Model 2017, developed by Argonne National Labs. It is shown that 59% and 63% greenhouse gas (GHG) reductions can be achieved in Indiana and California respectively, along with reduction in carbon monoxide (CO), nitrogen oxides NOx, particulate matter with diameter less than 2.5 microns PM2.5 and volatile organic compounds (VOC) emissions for both the states. However, an increase in sulfur oxides SOx emissions for both the states, and particulate matter with diameter less than 10 microns PM10 increase for Indiana, are observed. </div><div><br></div>

Em vigência desde Janeiro de 2012, a regulamentação Proconve P7 para veículos comerciais pesados exige que a demonstração de emissões de poluentes do motor seja realizada no ciclo de teste transiente europeu (ETC), desenvolvido de acordo com perfil de condução tipicamente europeu e assim pouco representativo de diversas situações de tráfego no Brasil. Especialmente quanto a aplicações de ônibus urbanos, altamente dinâmicas e submetidas a perfis de baixa velocidade e média carga, não é possível correlacionar plenamente o funcionamento do motor e seus sistemas de controle de emissões baseando-se apenas neste ciclo. Com essa motivação, o principal objetivo deste estudo é desenvolver ciclos de teste compactos para banco de provas de chassis e de motores que representem as condições reais de condução de ônibus urbanos da cidade de São Paulo. Estes ciclos de teste específicos possibilitam avaliações mais precisas não apenas das emissões de poluentes, mas também do consumo de combustível, além de proporcionarem melhor compreensão do real desempenho de motores e novas tecnologias dos sistemas de propulsão usados em frotas de ônibus urbanos no Brasil. A metodologia aplicada para construção dos ciclos utiliza o conceito de potência específica veicular (VSP), variável que apresenta alta correlação com emissões de poluentes e consumo de combustível e é calculada a partir de dados coletados em condições reais de condução de ônibus (velocidade, aceleração e inclinação das vias). A seleção dos veículos e linhas para realização das aquisições de dados considera tanto as especificações de trem-de-força e de chassis disponíveis na frota, como também os índices operacionais e a topografia dos trajetos como métodos para determinação de linhas com perfil operacional mais representativo. Como resultado do estudo foram propostos cinco ciclos de teste, um para cada tipo de ônibus selecionado (miniônibus, midiônibus, básico, padron e articulado), e as análises comparativas com o ciclo ETC quanto ao comportamento do motor mostram claramente a falta de representatividade do ciclo europeu adotado pela regulamentação brasileira. / Since January 2012, the Proconve P7 regulation is mandatory for heavy duty commercial vehicles requiring that the demonstration of pollutant gases emissions must be carried out by submitting the engine to the European transient test cycle (ETC), which has been developed according to European driving patterns and therefore is not representative of several driving situations in Brazil. Particularly for driving patterns of urban buses, which are highly dynamic with low vehicle speed and medium load profiles, it is not possible to fully correlate the operating conditions of the engine and its emission control systems based only on this test cycle. With this motivation, the main objective of this study is to develop compact test cycles for use in both chassis and engine test benches that represent the actual driving pattern of transit buses in São Paulo city. These specific test cycles may allow more accurate assessment of pollutant gases emissions and fuel consumption, as well as provide a better understanding concerning the real performance of engines and new propulsion technologies used in urban bus fleets in Brazil. The methodology used for construction of the cycles is based on the concept of vehicle specific power (VSP), a variable that is highly correlated with pollutant emissions and fuel consumption and is calculated from data collected under real-world driving conditions (vehicle speed, acceleration and road grade). The selection of the buses and routes for the on-board data collection considers the specifications of powertrain and chassis that are available in the bus fleet of São Paulo\'s public transportation system, operational indexes and route topography as a method for determining the bus routes with a more representative operational pattern. As the result of this study five test cycles were proposed, one for each bus type (minibus, midibus, basic, padron and articulated), and an analysis of the engine\'s operating behavior in comparison to the ETC cycle clearly shows the lack of representativeness of the European cycle adopted by the Brazilian regulation.

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