1,791 research outputs found
Multi-Level Energy Management for Hybrid Electric Vehicles—Part I
Full text linkThe fuel economy of a hybrid electric vehicle (HEV) is improved, by taking the energy relevant system states into account in the energy management system (EMS). With an increasing number of states and decision variables, energy optimizing algorithms in the EMS can be prohibitive for real-time implementation. In part I of this work, a model-based, multi-level approach is taken to subdivide the original (large) optimization problem into computational efficient sub-problems, based on optimal control techniques using a preview. The resulting EMS solves the problem of power-split between engine and motor/generator, mode and gear switching including switching costs, with battery energy constraints. The superior energy efficiency of the multi-level EMS is simulated on a representative heavy duty drive cycle, where it saves 7.0% fuel, compared to a conventional vehicle, where the baseline EMS for the HEV saves 5.8%. In part II, real-world validation of the EMS is performed
Multi-Level Energy Management—Part II: Implementation and Validation
Full text linkIn hybrid electric vehicles, energy management systems (EMS) using optimization show superior fuel efficiency compared to rule-based strategies. However, little research shows its real-life applicability. In Part II of this work, the multi-level, model-predictive EMS from Part I is implemented on a heavy-duty parallel hybrid electric vehicle, using GPS and map data as preview. The power split, hybrid mode, and gear selection, including switching costs, are optimized in real time, thereby proving the feasibility of optimal control techniques for hybrid driveline control. Functional validation of the EMS on a test track confirm the fuel-saving mechanism as simulated in Part I. In addition to a fuel saving of 36%, the EMS also improves the drivability, by reducing the amount of open driveline events
Battery-Electric Powertrain Design Analysis for an Efficient Passenger Vehicle
Full text linkIn this paper, different battery-electric powertrain designs have been investigated for a passenger hatchback vehicle. Specifically, the energetic effect of technological and topological choices in the powertrain design is analyzed. Thereto, a feasible set of battery electric powertrain configurations, varying in topology, machine technology, and transmission architecture is considered. For each configuration, the electric machine size(s), gear ratio value(s), and controls are jointly optimized in an integrated (bi-level) fashion using the particle swarm optimization (PSO) algorithm. The results showcase that the combined component and topological choices can lead to a maximum reduction of 17.61% in the vehicle’s energy consumption and can significantly influence the total electric machine sizing in the powertrain. Furthermore, it has been shown that the energy consumption of the vehicle is lowered by: (i) using two axles (AWD) instead of one axle (RWD) to drive the vehicle (-12.0%); (ii) choosing a distributed drive system, over a central drive system (-6.6%); followed by (iii) using permanent-magnet-synchronous type machine(s) instead of asynchronous induction machines (-3.0%); and, (iv) using multiple electric machines in single-axled topologies (-0.80%). The smallest energetic impact was observed for (v) using two-speed instead of single-speed gear box(es) (-0.38%); however, it resulted in the largest reduction in the (total) electric machine size(s) (-10.3%)
Synchronization Overhead in SOC Compressed Test
No full textTest data compression is an enabling technology for low-cost test. Compression schemes however, require communication between the system under test and the automated test equipment. This communication, referred to in this paper as synchronization overhead, may hinder the effective deployment of this new test technology for core-based systems-on-a-chip. This paper analyzes the sources of synchronization overhead and discusses the different trade-offs, such as area overhead, test time and automatic test equipment extensions. A novel scalable and programmable on-chip distribution architecture is proposed, which addresses the synchronization overhead problem and facilitates the use of low cost testers for manufacturing test. The design of the proposed architecture is introduced in a generic framework, and the implementation issues (including the test controller and test set preparation) have been considered for a particular case
Transmission Ratio Design for Electric Vehicles via Analytical Modeling and Optimization
Full text linkIn this paper we present an effective analytical modeling approach for the design of the transmission of electric vehicles. Specifically, we first devise an analytical loss model for an electric machine and show that it can be accurately fitted by only sampling three points from the original motor map. Second, we leverage this model to derive the optimal transmission ratio as a function of the wheels' speed and torque, and use it to optimize the transmission ratio. Finally, we showcase our analytical approach with a real-world case-study comparing two different transmission technologies on a BMW i3: a fixed-gear transmission (FGT) and a continuously variable transmission (CVT). Our results show that even for e-machines intentionally designed for a FGT, the implementation of a CVT can significantly improve their operational efficiency by more than 3%. The provided model will ultimately bridge the gap in understanding how to efficiently specify the e-machine and the transmission technology in an integrated fashion, and enable to effectively compare single- and multi-speed-based electric powertrains
Fifty Forensic Fables
No full textThis book does for the legal profession in England what George Ade's fables do more broadly. These are enjoyable tales with pleasing caricatures. All the actors are humans. A funny appendix follows The Story of an Ancient Line through twelve generations. The book shows what fable meant earlier in this century.This is a hardbound book (hard cover)This book has a dust jacket (book cover)O (Theo Mathew
Corporate and Public Real Estate managament
No full textIn this book chapter Theo van der Voordt and Monique Arkesteijn discuss the difference between corporate and public real estate management i.e. the perspective of the end users, and real estate management i.e. the perspective of investors and developers. Furthermore an overview is presented of the legacy of the (C)REM section of the Department of Management in the Built Environment of the Faculty of Architecture and the Built Environment, Delft University of Technology, the Netherlands. The chapter discusses various research themes and introduces key topics such as how to create the best possible fit between supply and demand, adding value through corporate and public real estate, managing of university campuses, workplace management, adaptive reuse as a means to cope with (structural) vacancy, preference modeling and willingness-to-pay, and Corporations & Cities. These topics have been elaborated in other chapters of “Dear is Durable”, a Liber Amicorum for prof. Hans de Jonge that was offered to him due to his farewell as professor of Real Estate Management and Development A pdf of this book can be downloaded from the TU Delft research repository: http://resolver.tudelft.nl/uuid:02789dc2-eb6f-41a7-9d64-21212c2a3da8 .Real Estate Managemen
The influence of mode change penalties on the comparison of hybrid drivetrain topologies
No full textHybrid drivetrains are systems with complex behavior of which finding the optimal design is a problem with a large design space. To assess a design on efficiency over a driving cycle, a control strategy is needed. Introducing mode change and engine start penalties in the optimization of the control increases the accuracy of the results at the cost of increased computation time. Yet, due to the large design space of the design problem, computation time is critical. In this work, an extensive case study is presented to analyze the influence of penalizing mode changes and engine starts on the comparison of hybrid drivetrain topologies. Eight different drivetrain topologies are considered, including parallel, series-parallel, and multimode powersplit topologies. For these topologies, the control is optimized over two driving cycles using dynamic programming with and without penalties. The introduction of mode change and engine start penalties reduces the number of mode changes by a factor of three to five, and the number of engine starts by approximately a factor of three. Yet, the influence on the fuel consumption comparison between the topologies is small: the largest change in relative fuel consumption is 0.36 percentage points, with the average absolute change over both cycles being 0.15 percentage points. The computation time is increased by approximately a factor of 26 due to the introduction of the penalties. Therefore, in the context of the system level design of hybrid drivetrains, it can be argued that the additional computation time outweighs the minor increase in accuracy provided by mode change penalties
Partners in Pollution Prevention
No full textThe concept of sustainability increasingly impacts the nature of industry’s operations. Whereas in the past sound economic performance was expected to guarantee success by companies and its shareholders, now increasingly business is led by the so-called triple bottom line. Achieving good economic results needs to be accompanied by minimisation of environmental impacts and increasing attention to social aspects. Over the years, environmental management has therefore developed into a strategic issue for industry. Adopting the triple bottom line implies that environmental management in organisations has to go beyond regulatory compliance and needs to include concepts such as pollution prevention, product stewardship and social responsibility
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