The Impact of a Microturbine Power Plant on an Off-Road Range
Total Page:16
File Type:pdf, Size:1020Kb
The Impact of a Microturbine Power Plant On an Off-Road Range-Extended Electric Vehicle Andrew Wyatt Zetts Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering Alfred L. Wicks, Chair Douglas J. Nelson Walter F. O‘Brien February 11, 2015 Blacksburg, VA Keywords: Microturbine, HEV, Autonomy Copyright © 2015 by Andrew W Zetts The Impact of a Microturbine Power Plant On an Off-Road Range-Extended Electric Vehicle Andrew Wyatt Zetts ABSTRACT The purpose of this thesis is to examine the feasibility of using a microturbine to power an off-road Series Hybrid Autonomous Vehicle (SHEV), and evaluate the benefits and drawbacks inherent in using a microturbine rather than an Internal Combustion Engine (ICE). The specific power plant requirements for a low speed hybrid vehicle that must operate extensively as an Electric Vehicle (EV) and run on JP-8 (a diesel equivalent) are unusual; few options can adequately address all of these needs. Most development of Hybrid Electric Vehicles (HEVs) has focused on gasoline ICE power plants, but Diesel ICEs are heavier, which has an adverse effect on EV range. While mechanically-linked turbine vehicles failed to have the same performance abilities of their ICE counterparts, a microturbine generator-powered SHEV can take advantage of its battery pack to avoid the issues inherent in its mechanical predecessors. A microturbine generator is mechanically decoupled from the powertrain, allowing for an incredibly power dense power plant that lightens the weight of the vehicle. This weight reduction directly correlates to an increased EV operational range, enhancing mobility, stealth, and the tactical effectiveness of the squad that the vehicle is intended to support. To determine the full impact that a microturbine might have on this specific SHEV, modeling of the vehicle was conducted to directly compare a microturbine and an ICE power plant using two drive cycles that were designed to simulate the typical operation specific to the vehicle. Drive cycle analysis revealed that the improved EV performance and design flexibility offered by the microturbine’s weight justifies the selection of a microturbine over an ICE for this specific case. This decision is dependent upon several factors: a microturbine with fuel efficiency comparable to an ICE, the selection of a large battery pack, and an emphasis on EV operations. ACKNOWLEDGEMENTS I would like to use this opportunity to express my gratitude to everyone who supported me throughout the course of writing this thesis, in an educational capacity, and during the writing process. I am deeply grateful to my advisor Al Wicks, who took me on as a graduate student after giving me a chance to prove myself based upon my hard work rather than grades alone. The research work I have done in the past few years has made me many times the engineer I ever was as an undergraduate. I would also like to thank the rest of my committee, Doug Nelson and Walter O’Brien, for serving on my committee. My thesis is stronger as a result of working with professors who are respected in their fields, both through their suggestions and my attempts to write to their standards. I would be unable to write a thesis with quantitative information if not for the help of TORC Robotics and Electric Jet of Blacksburg, VA. By providing me with localization data and Turbine efficiency data, I was able to construct drive cycle modeling based upon actual data, moving beyond hypothetical scenarios to demonstrate that this design has merit. As there is very little data publically available for either of these very specific applications, I truly could not have done this work without them, and I am truly thankful. The work ethic and passion of both of these growing companies is contagious. I have had the pleasure of working side-by-side with TORC for several years now, which has made me a more efficient and professional engineer. Electric Jet has been more than happy to meet with me whenever I have had questions about microturbines operation and design. Their hard work in the development of a small lightweight microturbine is very apparent and I have benefitted immensely as a result. I have been blessed to have worked with some of the best masters students in the world in the Applied Autonomy lab. My work with Chuck and David during my senior year on developing a proof of concept hybrid GUSS vehicle helped me enormously in the development of this thesis. Along with incredible guidance from John, the skills I learned from working on that project helped me in my work, both in the garage and at my desk. Phillip did much of the ground work for developing the concept of a hybrid GUSS, and my work builds off of his thesis. I am thankful for everyone who I’ve worked with in the GUSS program. I have had the pleasure of designing and developing the ITV-GUSS alongside several other talented engineers. The working relationship that I have developed with the engineers from the many entities involved in the project has prepared me for the professional world, and I hope that this thesis can benefit them a fraction as much as I have benefitted from them. In the past year I’ve struggled alongside Philip to finish building and maintaining the ITV-GUSS fleet, and I would never have been able to meet GUSS deadlines (let alone finish this thesis) if not for him. Finally, I would like to thank my friends and family for their support. My mother and father have demonstrated an unwavering belief in me, and I am thankful for the work ethic they iii instilled in me as a child. I hope I have made you proud. Special thanks go to Sarah for helping me edit when my grammatical skills were lacking. Last but not least, my years in graduate school would have been much harder if not for the dedication and love of my girlfriend Kelley. You have always supported me when my research has required long hours. Your dedication and assistance, even when this thesis shortened my winter break to a couple of days, is truly humbling. iv TABLE OF CONTENTS Acknowledgements .................................................................................................................... iii Table of Contents ........................................................................................................................ v List of Figures .......................................................................................................................... viii List of Tables ............................................................................................................................... x Acronymns and Abbreviations ................................................................................................... xi CHAPTER 1 PROBLEM DEFINITION AND APPROACH .............................................. 1 1.1 Introduction ...................................................................................................................... 1 1.2 Thesis Statement .............................................................................................................. 2 1.3 Background of Turbines Powered Vehicles ..................................................................... 4 1.4 Background of the Ground Unmanned Support Surrogate Program ............................... 5 1.4.1 GUSS Mission Goals ............................................................................................ 5 1.4.2 Previous GUSS Vehicles ....................................................................................... 5 1.4.3 HEV-GUSS Performance Standards ..................................................................... 7 1.5 Thesis Content .................................................................................................................. 7 CHAPTER 2 TECHNOLOGY REVIEW........................................................................ 9 2.0 Chapter Introduction ........................................................................................................ 9 2.1 Hybrid Vehicles................................................................................................................ 9 2.1.0 Section Summary .................................................................................................. 9 2.1.1 Theory of Hybrid Vehicles .................................................................................... 9 2.1.2 Power Plant to Energy Storage relationship ........................................................ 10 2.2 Microturbines ................................................................................................................. 16 2.2.1 Section Summary ................................................................................................ 16 2.2.2 Basic Turbine Overview...................................................................................... 16 2.2.3 Microturbine Overview ....................................................................................... 17 CHAPTER 3 DEFINING A MODEL TO BENCHMARK VEHICLE PERFORMANCE ....24 3.0 Chapter Summary ........................................................................................................... 24 3.1 Drive Cycle Analysis ..................................................................................................... 24 3.1.1 Drive Cycle Design ............................................................................................