With the introduction of electronic control units to automotive vehicles, system complexity has increased. With this change in complexity, new standards have been created to ensure safety at the system level for these vehicles. Furthermore, vehicles have become increasingly complex with the push for electrification of automotive vehicles, which has resulted in the creation of hybrid electric and battery electric vehicles. The goal of this thesis is to provide an example of a hazard and operability analysis as well as a hazard and risk analysis for a hybrid electric vehicle. Additionally, the safety standards developed do not align well with educational prototype vehicles because the standards are designed for corporations. The hybrid vehicle supervisory controller example within this thesis demonstrates how to define a system and then perform system-level analytical techniques to identify potential failures and associated requirements. Ultimately, through this analysis suggestions are made on how best to reduce system complexity and improve system safety of a student built prototype vehicle. / Master of Science / With the introduction of electronic control units to automotive vehicles, system complexity has increased. With this change in complexity, new standards have been created to ensure safety at the system level for these vehicles. Furthermore, vehicles have become increasingly complex with the push for electrification of automotive vehicles, which has resulted in the creation of hybrid electric and battery electric vehicles. There are different ways for corporations to demonstrate adherence to these standards, however it is more difficult for student design projects to follow the same standards. Through the application of hazard and operability analysis and hazard and risk analysis on the hybrid vehicle supervisory controller, an example is provided for future students to follow the guidelines established by the safety standards. The end result is to develop system requirements to improve the safety of the prototype vehicle with the added benefit of making design changes to reduce the complexity of the student project.

With automobile propulsion energy sources turning away from petroleum, the evolution of technology naturally lends itself to electrical hybrid vehicle architectures relying on alternatives as a primary electrical energy source. This thesis presents a design solution of a direct-drive and drive-by-wire prototype of a hybrid extended range electric vehicle (EREV) based on a dune buggy test bed. The developed setup eliminates nearly all mechanical inefficiencies in the rear wheel drive transaxle drivetrain. All controls have been purposely designed as a duplicate set to allow for full independent control of both rear wheels in a truly independent architecture. Along with the controls supporting the design, the motors have been mounted in a near wheel fashion to adequately replace a true hub motor setup. In addition, by-wire throttle and by-wireless brakes in a servomechanical fashion have been developed. The by-wireless braking system is used to control regenerative braking for the rear of the vehicle only allowing for the front brakes to be the primary means of braking as well as a mechanical safety redundancy. This design allows for developments in the areas of truly independent electronic differential systems and studies of the effect of near wheel motor setup. The efficiencies gained by the design solutions implemented in this thesis project have shown their ability to be used in a functioning motor vehicle. Direct gains in mechanical efficiency as well as the removal of a non eco-friendly gasoline powertrain have been attained. In addition, an electric architecture has been developed for further research in future studies such as vehicle stability control, traction control and all-wheel-drive architectures.

Following the Model-Based-Design (MBD) development process used presently by the automotive industry, the control systems for a new Series-Parallel Multiple-Regime Plug-in Hybrid Electric Vehicle (PHEV), UVic EcoCAR2, have been developed, implemented and tested. Concurrent simulation platforms were used to achieve different developmental goals, with a simplified system power loss model serving as the low-overhead control strategy optimization platform, and a high fidelity Software-in-Loop (SIL) model serving as the vehicle control development and testing platform. These two platforms were used to develop a strategy-independent controls development tool which will allow deployment of new strategies for the vehicle irrespective of energy management strategy particulars. A rule-based energy management strategy was applied and calibrated using genetic algorithm (GA) optimization. The concurrent modeling approach was validated by comparing the vehicle equivalent fuel consumption between the simplified and SIL models. An equivalency factor (EF) of 1 was used in accounting for battery state of charge (SOC) discrepancies at cycle end. A recursively-defined subsystem efficiency-based EF was also applied to try to capture real-world equivalency impacts. Aggregate results between the two test platforms showed translation of the optimization benefits though absolute results varied for some cycles. Accuracy improvements to the simplified model to better capture dynamic effects are recommended to improve the utility of the newly introduced vehicle control system development method. Additional future work in redefining operation modes and mode transition threshold conditions to approximate optimal vehicle operation is recommended and readily supported by the control system platform developed. / Graduate / 0540 / 0548 / 0790 / d.e.prescott@gmail.com

This thesis describes the development of an electrical system for a solar powered racing vehicle with en emphasis on the Battery Protection System (BPS). This battery protection system was designed for the UTSVT’s (University of Texas Solar Vehicles Team) solar powered vehicle, the Samsung Solorean. The system is required due to the dangers of the lithium-ion cobalt battery chemistry. The system monitors the voltage, temperature, and current of each battery module in the 22 module battery pack and will physically isolate the pack from the rest of the vehicle with a high-current electromechanical contactor if any parameter is outside of the safe range. The system can be expanded to monitor any number of series battery cells. The system uses a master-slave microcontroller architecture with a single master microcontroller that interrogates several slave microcontroller boards for readings over a common serial bus. The system uses a new voltage sensing ASIC to monitor cell voltages, along with an analog current output device to measure temperature and a hall-effect device to measure current. The system was a complete success and has allowed the UT solar car to finish the American Solar Challenge cross-country “Rayce.” / text

The internal combustion engine (ICE) vehicle has dominated the transportation market for nearly 100 years. Numerous concerns with continued use of fossil fuels arise, however, and these concerns have created an impetus to develop more efficient vehicles that release fewer emissions. There are several powertrain technologies that could supplant conventional ICEs as the dominant technology, most notably electric and hybrid powertrains. In order to achieve the levels of performance and cost of conventional powertrains, electric and hybrid powertrain designers must use design techniques and tools such as computer modelling, simulation and optimization. These tools facilitate development of a virtual prototype that allows the designer to rapidly see the effects of design modifications and precludes the need to manufacture multiple expensive physical prototypes. A comprehensive survey of the state of the art of commercialized hybrid vehicle powertrains is conducted, and the term multi-regime in ICE hybrid vehicle (ICEHV) modelling is introduced to describe designs that allow for multiple configurations and operating regimes. A dynamic mathematical model of a power-split architecture with two modes (or configurations) introduced by General Motors Corporation is developed and a steady-state version is programmed into the ADvanced VehIcle SimulatOR (ADVISOR) simulation software package. This ADVISOR model is applied to a commercial delivery vehicle, and the fuel consumption of the vehicle undergoing a variety of drive cycles is determined. The two-mode model is compared to the ADVISOR models for the Toyota Hybrid System (THS), parallel hybrid, and conventional powertrains in the same vehicle. The results show that for this vehicle type, the two-mode design achieves lower fuel consumption than the THS and conventional powertrains, and only slighter greater fuel consumption than the parallel hybrid design. There is also considerable potential for improvement in performance of the two-mode model through the development of an optimal power management strategy. In the medium- to long-term, the necessity for zero-emission vehicles may position fuel cell systems (FCSs) to be commercialized as on-board energy conversion devices. FCSs are currently inordinately expensive with power density and durability issues, among other design problems. Fuel cell hybrid vehicle (FCHV) designers must use the available design techniques intelligently to overcome the limitations and take advantage of the higher efficiency capabilities of the fuel cell. As the first step in creating a virtual prototype of a FCS, a semi-empirical model of the system is developed and further enhancements such as transient response modelling are proposed. An optimization of the operating parameters to maximize average net power and average exergetic efficiency is conducted, and the technique is applied to the FCS model for the prototype fuel cell hybrid scooter (FCHS). The optimizations demonstrate that significant improvements in performance can be achieved, and that optimizations with more design variables are warranted. Models of a conventional battery scooter (BS) and of the FCHS are developed in ADVISOR. Simulations are conducted which compare the performance of the two models. Subsequently, performance tests of the BS and FCHS are conducted using a chassis dynamometer. Despite problems with the prototype FCHS, the tests confirm the theoretical results: the FCHS model achieves higher performance in terms of acceleration and power, while the BS model operates more efficiently and requires less energy. This study provides better understanding on the emerging FCHV and ICEHV technologies; introduced new and improved models for FCHV and multi-regime hybrid powertrains; developed FCHV and ICEHV performance simulation and design optimization methods using the new computer models; explored the methods for validating the computer models using prototype BS and FCHS on a research dynamometer; identified areas of improvements of the new experiment methods; and formed the foundation for future research in related areas.

A series hybrid electric vehicle is a vehicle that is powered by both an engine and a battery pack. An electric motor provides all of the mechanical motive power to the transmission. Engine power is decoupled from the transmission by converting engine power into electricity which powers the electric motor. The mechanical decoupling of the engine from the transmission allows the engine to be run at any operating point (including off) during vehicle operation while the battery back supplies or consumes the remaining power. Therefore, the engine can be operated at its most efficient operating point or in a high-efficiency operating region. The first objective of this research is to develop a dynamic model of a series hybrid diesel-electric powertrain for implementation in Simulink. The vehicle of interest is a John Deere M-Gator utility vehicle. This model serves primarily to test energy management strategies, but it can also be used for component sizing given known load profiles for a vehicle. The second objective of this research is to develop and implement multiple energy management strategies of varying complexity from simple thermostat control to an optimal control law derived using dynamic programming. These energy management strategies are then tested and compared over the criteria of overall fuel efficiency, power availability, battery life, and complexity of implementation. Complexity of implementation is a critical metric for control designers and project managers. The results show that simple point-based control logic can improve upon thermostat control if engine efficiency maps are known. All control method results depend on the load profile being used for a specific application.

Dans le cadre du développement du véhicule électrique hybride, les machines électriques pour la traction sont l’objet d’un effort toujours plus important de recherche et de développement. En particulier, les contraintes d’encombrement allouées à ces machines sont toujours plus sévères et la recherche se porte vers des structures de machines compactes. C’est dans ce contexte que nos travaux se sont portés sur l’étude et le dimensionnement de machine à flux axial pour une application hybridation douce (Mild Hybrid) d’alterno-démarreur monté sur vilebrequin de puissance 50 kW et de couple 205 Nm en régime transitoire. Un état de l’art des machines à flux axial est présenté. Une analyse des configurations de bobinage avec la méthode de l’étoile des encoches est détaillée. Un début d’analyse de la machine à commutation de flux est proposé. La méthodologie de dimensionnement est étayée. Elle repose sur des études de sensibilité, un dimensionnement paramétrique, mais aussi une optimisation de la machine. Les modèles utilisés sont de type éléments finis et surface de réponse par plan d’expériences. Enfin, une étude thermique de la machine est effectuée et des pistes sont données pour l’amélioration de l’échange thermique par refroidissement diphasique. / In the context of development of the hybrid electric vehicle, electric machines for traction are under extensive investigation. In particular, volume constraints are more and more severe and research is carried out towards compact structures. This work is focused on the study and the design of axial flux machine for a mild-hybrid application of an integrated starter generator mounted on the crankshaft. Its ratings in transient mode are 50 kW and 205 Nm. A literature review of axial flux machines is presented. A analysis of winding configurations with star of slots method is detailed. A beginning of analysis of switching-flux machine is proposed. The methodology of design is detailed. It is based on sensitivity analysis, parametric design and optimization of the machine. Utilized models are finite element model and response surface by design of experiments. Finally, a thermal study of the machine is carried out and some ideas are given to improve the thermal exchange by diphase cooling.

Les préoccupations environnementales croissantes et la raréfaction des énergies fossiles amènent les constructeurs automobiles à proposer des véhicules efficients hybridant des chaînes de traction conventionnelles. Ces travaux de recherche sont focalisés sur l'hybridation thermique/électrique. Ils présentent une méthodologie de conception optimale pour identifier des voies de progrès et orienter la définition de futures chaînes de traction à haut rendement énergétique. Ils sont basés sur une démarche d'ingénierie systémique qui s'appuie sur trois principaux leviers: l'architecture de la chaîne de traction, la stratégie de gestion énergétique et la définition des organes électriques de puissance. Différentes architectures de chaînes de traction hybrides électriques sont comparées en se basant sur la consommation minimale atteignable par chacune d'entre elles sur cycles automobiles. Pour déterminer ces seuils de consommation, une stratégie de commande optimale basée sur un algorithme de programmation dynamique est développée. Les résultats montrent l'intérêt de l'hybridation parallèle pour concevoir une chaîne de traction efficiente.Les sollicitations des organes électriques de puissance sont déterminées et analysées pour en spécifier le dimensionnement optimal. Deux structures de machines électriques ont été modélisées par réseaux de réluctances pour établir des cartographies de pertes et comparer la performance en émissions de CO2 du véhicule. Cette approche permet d'identifier des axes d'améliorations et on montre qu'une solution de type alterno-démarreur permettrait des gains d'environ 33% en émissions de CO2 par rapport au véhicule conventionnel. / On-going oil stock depletion and growing environmental concerns lead automakers to develop more efficient powertrains. Today, one of the most promising way forward consists in research on hybrid systems. The present work is focused on thermal/electric hybridization for HEV vehicle and presents an optimal methodology to identify key guidelines and design efficient systems. Defining the most promising efficient powertrain requires a systemic design which is based in this study on three main levers : powertrain architecture, energy management and electric components design. Different powertrains architectures are compared to the lowest fuel consumption that can be reached by each powertrain for a given driving cycle. Their optimal energetic performances are determined by using optimal control strategies and dynamic programming. The simulations results show that the most promising hybrid powertrain is the parallel one. At each step of time of the drivings cycles, the parallel hybrid powertrain behavior is more closely analyzed so as to provide technical specifications for an optimal sizing of the electric components. It points out the operating point and the driving cycles for which the electric machine has to be optimized. Two electric machines topologies derived from a starter-alternator architecture, are modeled by using reluctance network to provide losses map and compare CO2 saving of the vehicle. This approach has both identified areas for powertrain architecture improvement and components design optimization to achieve a better global efficiency of the system. It is shown that a starter-alternator could provide 33% of CO2 saving compared to a conventional car.

The content of this thesis is analysis of energy flows of the propulsion system in plug-in hybrid utility vehicle. Theoretical part of the thesis deals with electrically assisted turbochargers, which can positively influence engine characteristics. The following part analyses given diesel engine and utility vehicle in simulations in GT-Suite software, with simulations being performed on WLTC driving cycle. The results of the simulations demonstrate the relation between the usage of electrical and fuel energies and the driving cycle and show the engine operation points. By using optimal battery capacity, it is possible to save according to driving cycle more than 50 % energy consumed by the engine, directly influencing the fuel consumption. The results are possible to use as a guidance for moving the engine operation points and for sizing of the battery pack of hybrid utility vehicle according to real life application.

Les progrès technologiques augmentent la complexité des systèmes énergétiques, ce qui permet d'avoir variés sources et architectures possibles. Si le contexte économique et écologique est également pris en compte, l'industrie automobile est menée à aligner sa production sur des véhicules hybrides ou électriques qui disposent d'une gestion de l'énergie sophistiquée. Ainsi, les études pour la conception sont orientées à l'optimisation et à la gestion de l'énergie en tenant compte les tendances des constructeurs : i) augmenter les performances des véhicules, ii) avoir des véhicules moins polluants en réduisant la consommation de carburant et iii) diminuer le temps nécessaire à la conception et au processus de validation. Face à ces problèmes, une approche qui aide le concepteur à caractériser le système de gestion de l'énergie d'un VEH est proposée. Cette caractérisation consiste à : i) choisir l'architecture de la chaîne de traction, ii) le dimensionnement des composants (groupes) et iii) le contrôleur de gestion de l'énergie. Pour accomplir ces tâches, une méthode de modélisation énergétique fonctionnelle est proposée. Cette approche proposée à un niveau d'abstraction "juste nécessaire" qui permet d'avoir une analyse énergétique pour une série de cas d'utilisation. La méthode repose sur des boucles de contrôle locales, un contrôleur global et des équations de base et elle permet d'avoir une optimisation modulaire pour tout changement d'architecture. Prochaine étape de la validation est l'adaptation du modèle fonctionnel afin d'obtenir le contrôleur de haut niveau pour le niveau multi-physique avec deux étapes proposées : i) l'ajustement des paramètres des éléments fonctionnels et ii) l'interconnexion les modèles fonctionnels et multi-physiques. Après l'illustration du démonstrateur d'un VEH, trois stratégies de gestion de l'énergie sont proposées : i) fondée sur des règles, ii) fondée sur PFC avec fonctionnement de partage de besoin par priorisation et iii) fondée sur PFC avec fonctionnement boost. Les stratégies de gestion de l'énergie proposées sont ensuite comparées par indicateurs de performance (consommation de carburant, nombre de cycles marche/arrêt du groupe motopropulseur et consommation de carburant corrigée avec variation de l'état de charge du stockage électrique) avec des cas d'usages définis. / Technology advancements increase the complexity of energy systems which bring additional varieties of sources and possible architectures to choose. If the economic and ecological context is also included, the automobile industry is in_uenced to align their production to hybrid or battery electric vehicles that have sophisticated energy management system. Thus, researchers and designers have oriented their studies for system design, optimisation and energy management that take into consideration the constructor tendencies : i) increasing vehicle performances, ii) having less polluting vehicles by reducing fuel consumption and iii) decreasing the time needed for design and validation process. Against these problematics, an approach that assists the system designer to fully characterize the energy management system of a HEV is proposed. This characterization consists : i) choosing powertrain architecture, ii) component (units) sizing and iii) energy management controller. In order to accomplish these tasks, a functional energetic modelling method is proposed. Proposed functional modelling level has a level of abstraction _just necessary_ which permits to have energetic analysis for a series of use case. This method relies on local control loops, a global controller and basic equations and it allows to have a modular optimisation for any architecture changes. The second-stage in the validation is completed by adapting the functional model in order to obtain the high-level controller for the multi-physical level with two offered steps : i) adjustment the functional elements' parameters and ii) interconnection the functional and multi-physical models. After the illustration of the demonstrator of a HEV, three strategies for energy management is proposed : i) based on rules, ii) based on PFC with power sharing function and iii) based on PFC with booster function. The proposed energy management strategies then compared by performance indicators (fuel consumption, number of on/off cycles of engine powertrain and corrected fuel consumption with variation of state of charge of electrical storage) with defined use cases.