EPA testing methods for calculation of fuel economy label ratings, which were revised beginning in 2008, use equations that weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. The equations incorporate effects with varying weightings into the final fuel consumption, which are explained in this thesis paper, including illustrations from testing. Some of the test results used in the computation come from individual phases within the certification driving cycles. This methodology causes additional complexities for hybrid electric vehicles, because although they are required to have charge-balanced batteries over the course of a full drive cycle, they may have net charge or discharge within the individual phases. The fundamentals of studying battery charge-balance are discussed in this paper, followed by a detailed investigation of the implications of per-phase charge correction that was undertaken through testing of a 2010 Toyota Prius at Argonne National Laboratory's vehicle dynamometer test facility. Using the charge-correction curves obtained through testing shows that phase fuel economy can be significantly skewed by natural charge imbalance, although the end effect on the fuel economy label is not as large. Finally, the characteristics of the current 5-cycle fuel economy testing method are compared to previous methods through a vehicle simulation study which shows that the magnitude of impact from mass and aerodynamic parameters vary between labeling methods and vehicle types. / Master of Science

Defining an operation strategy for a Split Parallel Architecture (SPA) Hybrid Electric Vehicle (HEV) is accomplished through calculating powertrain component losses. The results of these calculations define how the vehicle can decrease fuel consumption while maintaining low vehicle emissions. For a HEV, simply operating the vehicle's engine in its regions of high efficiency does not guarantee the most efficient vehicle operation. The results presented are meant only to define a literal strategy; that is, an understanding as to why the vehicle should operate in a certain way under the given conditions. The literature review gives a background of hybrid vehicle control publications, and without the SPA HEV addressed or a hybrid analysis based on loss calculations between engine only and hybrid modes, there is a need for this paper. Once the REVLSE architecture and components are understood, the hybrid modes are explained. Then the losses for each hybrid mode are calculated, and both the conversion and assist efficiencies are detailed. The conversion efficiency represents the amount of additional fuel required to store a certain amount of energy in the battery, and this marginal efficiency can be higher than peak engine efficiency itself. This allows electric only propulsion to be evaluated against the engine only mode, and at low torques the electric motor is more efficient despite the roundtrip losses of the hybrid system. / Master of Science

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

Throughout the past several years, a major push has been made for the automotive industry to provide vehicles with lower environmental impacts while maintaining safety, performance, and overall appeal. Various legislation has been put into place to establish guidelines for these improvements and serve as a challenge for automakers all over the world. In light of these changes, hybrid technologies have been growing immensely on the market today as customers are seeing the benefits with lower fuel consumption and higher efficiency vehicles. With the need for hybrids rising, it is vital for the engineers of this age to understand the importance of advanced vehicle technologies and learn how and why these vehicles can change the world as we know it. To help in the education process, this thesis seeks to define a powertrain model created and developed to help users understand the basics behind hybrid vehicles and the effects of these advanced technologies. One of the main goals of this research is to maintain a simplified approach to model development. There are very complex vehicle simulation models in the market today, however these can be hard to manipulate and even more difficult to understand. The 1 Hz model described within this work aims to allow energy to be simply and understandable traced through a hybrid powertrain. Through the use of a 'backwards' energy tracking method, demand for a drive cycle is found using a drive cycle and vehicle parameters. This demand is then used to determine what amount of energy would be required at each component within the powertrain all the way from the wheels to the fuel source, taking into account component losses and accessory loads on the vehicle. Various energy management strategies are developed and explained including controls for regenerative braking, Battery Electric Vehicles, and Thermostatic and Load-following Series Hybrid Electric Vehicles. These strategies can be easily compared and manipulated to understand the tradeoffs and limitations of each. After validating this model, several studies are completed. First, an example of using this model to design a hybrid powertrain is conducted. This study moves from defining system requirements to component selection, and then finding the best powertrain to accomplish the given constraints. Next, a parameter known as Power Split Fraction is studied to provide insight on how it affects overall powertrain efficiency. Since the goal with advanced vehicle powertrains is to increase overall system efficiency and reduce overall energy consumption, it is important to understand how all of the factors involved affect the system as a whole. After completing these studies, this thesis moves on to discussing future work which will continue refining this model and making it more applicable for design. Overall, this work seeks to provide an educational tool and aid in the development of the automotive engineers of tomorrow. / Master of Science

As the global demand for energy increases, the people of the United States are increasingly subject to high and ever-rising oil prices. Additionally, the U.S. transportation sector accounts for 27% of total nationwide Greenhouse Gas (GHG) emissions. In the U.S. transportation sector, light-duty passenger vehicles account for about 58% of energy use. Therefore incremental improvements in light-duty vehicle efficiency and energy use will significantly impact the overall landscape of energy use in America. A crucial step to designing and building more efficient vehicles is modeling powertrain energy consumption. While accurate modeling is indeed key to effective and efficient design, a fundamental understanding of the powertrain and auxiliary systems that contribute to energy consumption for a vehicle is equally as important if not more important. This thesis presents a methodology that has been packaged into a tool, called VTool, that can be used to estimate the energy consumption of a vehicle powertrain. The method is intrinsically designed to foster understanding of the vehicle powertrain as it relates to energy consumption while still providing reasonably accurate results. VTool explicitly calculates the energy required at the wheels of the vehicle to complete a prescribed drive cycle and then explicitly applies component efficiencies to find component losses and the overall energy consumption for the drive cycle. In calculating component efficiencies and losses, VTool offers several tunable parameters that can be used to calibrate the tool for a particular vehicle, compare powertrain architectures, or simply explore the tradeoffs and sensitivities of certain parameters. In this paper, the method is fully and explicitly developed to model Electric Vehicles (EVs), Series Hybrid Electric Vehicles (HEVs) and Parallel HEVs for various different drive cycles. VTool has also been validated for use in UDDS and HwFET cycles using on-road test results from the 2011 EcoCAR competition. By extension, the method could easily be extended for use in other cycles. The end result is a tool that can predict fuel consumption to a reasonable degree of accuracy for a variety of powertrains, calculate J1711 Utility Factor weighted energy consumption for Extended Range Electric Vehicles (EREVs) and determine the Well-to-Wheel impact of a given powertrain or fuel. VTool does all of this while performing all calculations explicitly and calculating all component losses to allow the user maximum access which promotes understanding and comprehension of the fundamental dynamics of automotive fuel economy and the powertrain as a system. / Master of Science

The purpose of this study was to determine Chinese and U.S. consumers' attitudes and perceptions toward hybrid cars and the likelihood of purchasing one in the future.

Unidades propulsoras híbrido elétricas são uma alternativa em potencial para a redução do consumo de combustível e emissões de poluentes, quando empregadas em veículos de transporte público. A configuração híbrido elétrica de interesse é a série, na qual as fontes de potência, para o motor elétrico de tração, são compostas por um banco de baterias e uma unidade formada pela junção entre um motor à combustão interna e um gerador. Na presente Dissertação foi realizada a modelagem de um veículo elétrico híbrido série na qual diferentes estratégias de gerenciamento de potência foram investigadas. Dentre as estratégias de interesse, duas são fundamentadas em regras e a terceira em sistemas fuzzy. Resultados obtidos comprovaram que a fundamentada em sistemas fuzzy possibilita maior economia de combustível, permitindo que o motor à combustão interna forneça menos potência, face o emprego das baseadas em regras. Dessa forma, a utilização de sistemas fuzzy no gerenciamento de potência do veículo, permite o emprego de um motor à combustão menos potente, de menor custo, sem o comprometimento do desempenho do veículo. As simulações do presente modelo de veículo híbrido foram realizadas no ambiente Matlab/Simulink® 7.3.0. / Hybrid electric propulsion units are a potential alternative to the reduction of fuel consumption and pollutant emissions, when used in public transport vehicles. The electric hybrid configuration of interest is the series, in which the energy supplies to the traction electric motor are composed of batteries and a unit represented by the connection of an internal combustion engine and a generator. This Dissertation presents the modeling of a series hybrid electric vehicle in which different energy management strategies were investigated. Among the strategies of interest, two are based on rules and one on fuzzy systems. The obtained results proved that the strategy based on fuzzy systems improved the fuel economy, allowing the internal combustion engine to supply less power than the use of the strategies based on rules. Therefore, the use of fuzzy systems in the energy management of the vehicle allows for the adoption of a less potent and cheaper internal combustion engine, without compromising the vehicles performance. The simulations of the present model of the hybrid electric vehicle were performed in the Matlab/Simulink® 7.3.0 environment.

Envisagée à partir des 15 à 30 années à venir dans l'industrie aéronautique, la propulsion hybrideélectrique permet d'intégrer de nouvelles briques technologiques offrant des degrés de libertésupplémentaires pour améliorer les performances des aéronefs, limiter l'utilisation de ressourcesfossiles et réduire l’impact environnemental des avions. Aujourd'hui, la technologie hybrideélectrique est principalement appliquée aux transports terrestres, aux voitures, aux bus et auxtrains, mais aussi aux navires. La faisabilité pour le transport aérien doit encore être établie etl'amélioration des performances des aéronefs reste à démontrer. Cette thèse vise à évaluer lesgains énergétiques apportés par l'hybridation électrique d'un avion régional de 70 places. Toutd'abord, les opportunités d'économie d'énergie sont identifiées à partir de l'analyse desrendements propulsifs et aérodynamiques d'un avion bi-turbopropulsé conventionnel. Les gainspotentiels provenant de la variation de la taille des moteurs principaux et de nouvelles gestions depuissance par l'utilisation de batteries sont étudiés. De plus, les possibles améliorationsaérodynamiques émanant de nouveaux positionnements des hélices sont considérées. Pourchaque sujet, des analyses simplifiées fournissent une estimation d'économie d'énergie. Cesrésultats sont ensuite utilisés pour sélectionner quatre systèmes propulsifs électrifiés qui sontétudiés plus en détail dans la thèse: un hybride parallèle, un turboélectrique avec propulsiondistribuée, un turboélectrique partiel à hélices hypersustentatrices, et un tout-électrique.L'évaluation des avions hybrides électriques sélectionnés est d'autant plus difficile que ledimensionnement des différentes composants, les stratégies de gestion d'énergie et les profils demission que l'on peut imaginer sont nombreux et variés. En outre, le processus global deconception de l'avion et les outils d'évaluation doivent être adaptés en conséquence. L'outilinterne de conception par optimisation multidisciplinaire d'Airbus nommé XMDO, qui inclut laplupart des modifications requises, est finalement sélectionné et développé au cours de la thèse.Par exemple, de nouveaux modèles paramétriques de composants (voilure soufflée, moteurélectrique, turbine à gaz, hélice, etc...) sont créés, une formulation générique pour résoudrel'équilibre du système de propulsion est mise en place, et les modèles de simulation de décollageet d'atterrissage sont améliorés. Afin d'évaluer l'efficacité énergétique des avions hybridesélectriques, un avion de référence équipé d'un système propulsif conventionnel est d'abordoptimisé avec XMDO. Différents algorithmes d'optimisation sont testés, et la consistance de lanouvelle méthode de conception est vérifiée. Par la suite, les configurations hybrides électriquessont toutes optimisées selon les mêmes exigences de conception que l'avion de référence. Pourles composants électriques, deux niveaux de technologie sont définis selon la date d'entrée enservice de l'aéronef. Les résultats d'optimisation pour le turbo-électrique et le turbo-électriquepartiel sont utilisés pour mieux appréhender les gains aérodynamiques potentiels identifiés enpremière partie de thèse. Les optimisations pour l'hybride parallèle, comprenant différentsscénarios de recharge batterie, mettent en évidence les meilleures stratégies de gestion d'énergielorsque des batteries sont utilisées comme sources d'énergie secondaire. Tous les résultats sontfinalement comparés à la référence en termes de consommations de carburant et d'énergie, pourles deux niveaux de technologie électrique. La dernière partie de la thèse se concentre sur l'aviontout électrique. Elle vise à identifier l'énergie spécifique minimale requise pour les batteries enfonction de la distance maximale à parcourir. Une étude de sensibilité est également réalisée enfonction de la date d'entrée en service pour les autres composants électriques / Envisioned in the next 15 to 30 years in the aviation industry, hybrid-electric propulsion offers theopportunity to integrate new technology bricks providing additional degrees of freedom to improveoverall aircraft performance, limit the use of non-renewable fossil resources and reduce the aircraftenvironmental footprint. Today, hybrid-electric technology has mainly been applied to groundbased transports, cars, buses and trains, but also ships. The feasibility in the air industry has to beestablished and the improvement in aircraft performance has still to be demonstrated. This thesisaims to evaluate the energy savings enabled by electric power in the case of a 70-seat regionalaircraft. First, energy saving opportunities are identified from the analysis of the propulsion andaerodynamic efficiencies of a conventional twin turboprop aircraft. The potential benefits comingfrom the variation of the size of prime movers and the new power managements with the use ofbatteries are studied. Also, possible aerodynamic improvements enabled by new propellerintegrations are considered. For each topic, simplified analyses provide estimated potential ofenergy saving. These results are then used to select four electrified propulsion systems that arestudied in more detail in the thesis: a parallel-hybrid, a turboelectric with distributed propulsion, apartial-turboelectric with high-lift propellers and an all-electric. Evaluating the selected hybrid-electric aircraft is even more challenging that the sizing of the different components, the energymanagement strategies and the mission profiles one can imagine are many and varied. Inaddition, the overall aircraft design process and the evaluation tools need to be adaptedaccordingly. The Airbus in-house Multidisciplinary Design Optimisation platform named XMDO,which includes most of the required modifications, is eventually selected and further developedduring the thesis. For examples, new parametric component models (blown wing, electrical motor,gas turbine, propeller, etc…) are created, a generic formulation for solving the propulsion systemequilibrium is implemented, and simulation models for take-off and landing are improved. In orderto evaluate the energy efficiency of the hybrid-electric aircraft, a reference aircraft equipped with aconventional propulsion system is first optimised with XMDO. Different optimisation algorithms aretested, and the consistency of the new design method is checked. Then, all the hybrid-electricconfigurations are optimised under the same aircraft design requirements as the reference. Forthe electrical components, two levels of technology are defined regarding the service entry date ofthe aircraft. The optimisation results for the turboelectric and the partial-turboelectric are used tobetter understand the potential aerodynamic improvements identified in the first part of the thesis.Optimisations for the parallel-hybrid, including different battery recharge scenarios, highlight thebest energy management strategies when batteries are used as secondary energy sources. All theresults are finally compared to the reference in terms of fuel and energy efficiencies, for the twoelectrical technology levels. The last part of the thesis focuses on the all-electric aircraft, and aimsat identifying the minimum specific energy required for batteries as a function of the aircraft designrange. A trade study is also carried-out in accordance with the service entry date for the otherelectrical components

Depuis une dizaine d’années, les constructeurs et les grands groupesdu secteur de l’automobile se sont mobilisés autour de la recherche et dudéveloppement de nouveaux prototypes de véhicules économes (moins consommateursd’énergie) et propres (moins de rejets de polluants) tels queles véhicules hybrides et tout électriques. C’est une nouvelle mutation. Ellefait profondément évoluer l’automobile, d’une architecture de propulsionthermique, devenue maîtrisée mais fortement polluante, vers une tractionélectrique ou hybride plus complexe et peu, voire pas du tout, maîtrisée ;le nombre de composants (sources d’énergie, actionneurs, contrôleurs, calculateurs,...) devient important, de nature multidisciplinaire et possédantbeaucoup de non linéarités. De plus, faute de maturité dans ce domaine, àce jour l’industrie de l’automobile ne possède pas encore les connaissancessuffisantes nécessaires à la modélisation, à la simulation et à la conceptionde ces nouveaux véhicules et plus particulièrement les dispositifs relatifs auxsources d’énergie et aux différents actionneurs de propulsion.Les travaux de cette thèse visent à donner des méthodes de conceptiond’une chaine de traction hybride et d’en gérer la gestion de l’énergie. Lathèse s’appuie sur l’exemple de la conception et la gestion de l’énergie d’unvéhicule hybride basé sur une pile à combustible et des batteries.Dans un premier temps, un méthode de dimensionnement des composantsde la chaine de traction est présentée : Elle consiste en l’étude statistique decycle de conduite générés pseudo aléatoirement représentatif de la conduiteen condition réelle de véhicule. Un générateur de cycle de conduite à été créeet est présenté, et la méthode de dimensionnement de la source primaire, iciune pile a combustible, ainsi que le source secondaire de puissance, ici desbatteries, est détaillée. Un exemple est pris pour illustrer cette méthode avecla conception d’un véhicule de type camion poubelle décrivant des cycles deconduites urbains à arrêts fréquents.Dans un second temps, la gestion de l’énergie de la chaine de traction hybridesérie est étudiée : une gestion de l’énergie “offline” est présentée, basé surl’optimisation par programmation dynamique. Cette optimisation permetd’avoir le découpage de la puissance par les deux sources de la chaine detraction de manière optimal pour un cycle précis. De part l’aspect déterministede la programmation dynamique, les résultats servent de référence quant aufuturs développements de gestion temps réel.Un contrôleur temps réel basé sur la logique floue est ainsi exposé et lesrésultats sont comparés par rapport à la gestion “offline”. Le contrôleurest ensuite optimisé et rendu adaptatif par un algorithme génétique et unalgorithme de reconnaissance de type de profil routier.Enfin, une introduction à la gestion de l’énergie dans les véhicules hybrides de type : “plug in” est présentée : Elle repose sur le principe de la déterminationde la distance restante à parcourir par la reconnaissance de la destination àl’aide d’une matrice de probabilité de Markov. / Hybrid electric vehicle have known a quickly grow in the last 10 years.Between conventional vehicles which are criticized for their CO2 emissionand electric vehicles which have a big issue about autonomy, hybrid electricones seems to be a good trade of. No standard has been set yet, and the architecturesresulting of theses productions vary between brands. Nevertheless,all of them are design as a thermal vehicle with battery added which leadsto bad sizing of the component, specially internal combustion engine andbattery capacity. Consequently, the control strategy applied to its componentshas a lot of constraints and cannot be optimal.This thesis investigate a new methodology to design and control a hybridelectric vehicle. Based on statistical description of driving cycle and the generationof random cycle, a new way of sizing component is presented. Thecontrol associate is then determined and apply for different scenarios : firstlya heavy vehicle : A truck and then a lightweight vehicle. An offline controlbased on the optimization of the power split via a dynamic programmingalgorithm is presented to get the optimal results for a given driving cycle.A real time control strategy is then define with its optimization for a givenpatterns and compared to the offline results. Finally, a new control of plug inhybrid electric vehicle based on destination predictions is presented.

This thesis (1) reports the development of simulation tools and control strategies for optimizing hybrid electric vehicle (HEV) energy management, and (2) reports the design and testing of a hydraulic hybrid school bus (HHB) prototype. A hybrid vehicle is one that combines two or more energy sources for use in vehicle propulsion. Hybrid electric vehicles have become popular in the consumer market due to their greatly improved fuel economy over conventional vehicles. The control strategy of an HEV has a paramount effect on its fuel economy performance. In this thesis, backward-looking and forward-looking simulations of three HEV architectures (parallel, power-split and 2-mode power-split) are developed. The Equivalent Cost Minimization Strategy (ECMS), which weights electrical power as an equivalent fuel usage, is then studied in great detail and improvements are suggested. Specifically, the robustness of an ECMS controller is improved by linking the equivalence factor to dynamic programming and then further tailoring its functional form. High-fidelity vehicle simulations over multiple drive-cycles are performed to measure the improved performance of the new ECMS controller, and to show its potential for online application. While HEVs are prominent in the consumer market and studied extensively in current literature, hydraulic hybrid vehicles (HHVs) only exist as heavy utility vehicle prototypes. The second half of this thesis reports design, construction, and testing of a hydraulic hybrid school bus prototype. Design considerations, simulation results, and preliminary testing results are reported, which indicate the strong potential for hydraulic hybrids to improve fuel economy in the school bus vehicle segment.