Design of High Performance Hybrid Transmissions by Daniel S. Dorsch S.B., Massachusetts Institute of Technology (2012) S.M., Massachusetts Institute of Technology (2015) Submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY September 2019 © Massachusetts Institute of Technology 2019. All rights reserved. Author.................Signatureredacted Department of Mechanical Engineering August 23, 2019 Certified by........ Signatureredacted ...... Amos G. Winter, V Associate Professor of Mechanical Engineering Signature redactedThesis Supervisor Accepted by.......... MASSACHETS INSGTITUTE OF TECHNOLOGY Nicolas Hadjiconstantinou Professor of Mechanical Engineering SEP 19 2019 Graduate Officer m LIBRARIES Ml j 2 Design of High Performance Hybrid Transmissions by Daniel S. Dorsch Submitted to the Department of Mechanical Engineering on August 23, 2019, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering Abstract This thesis explores the design, development, and evaluation of transmission systems for integration into high-performance hybrid (internal combustion engine (ICE) and electric motor) vehicles. Traditional hybrid vehicle designs often fall into one of two categories. Every day road vehicles typically utilize hybridization for increased drivetrain efficiency, including traits such as low speed electric drive and regenerative braking. Alternatively, performance cars have typically utilized the electric motor functionality for increased performance. By using a new framework for analyzing the elements and their function within a propulsion system architecture, advanced hybrid architectures that allow for both high efficiency and increased performance are presented. A two-motor, clutchless hybrid transmission concept was developed. An analysis of driving modes available demonstrates the utility in a high-performance vehicle, increasing the performance and efficiency of the drivetrain. A second, dual- shaft, single motor, clutchless transmission concept is presented, with the benefits and drawbacks of this architecture compared to the two-motor architecture, and a traditional ICE only transmission. The final part of this thesis presents a novel, two-speed electric motor system that could be integrated within a conventional ICE automated manual transmission. This system utilizes custom sensors for tracking the position of the dogteeth within the two-speed shift synchronizer. Electric motor control is used to synchronize mo- tor speed during a shift event, as the inertia of the electric motor is too large for friction synchronization alone to be sufficient. This strategy removes the tradeoff that currently exists for optimal shift actuator design (larger pistons result in faster speed synchronization but slower actuation motion during other phases of a shift) and results in overall faster gearshifts. Dogtooth tracking allows for firing of the shift actuator at the proper moment, ensuring no collision between dogteeth and allow- ing for faster shifter motion than with a traditional synchronizer. An experimental setup was developed to characterize shift performance. Full gearshifts can be made successfully utilizing speed matching and dogtooth tracking, validating the described shift control method and allowing for improved, frictionless synchronizer designs. The 3 developments described in this work will lead to a new generation of hybrid vehicles, designed for high-performance and increased efficiency. Thesis Supervisor: Amos G. Winter, V Title: Associate Professor of Mechanical Engineering 4 Acknowledgments I would like to thank the following people and organizations for their contributions to my work: " Natasha Wright - thank you for your help on everything with my research and thesis. Without all of your help this would not have been possible. I have enjoyed our time together in the lab and activities around Boston, and look forward to the many new adventures to come! * Thank you Franco Cimatti, Andrea Canaparo, Fabrizio Favaretto, and Luca Splendi for your information and help during this project. It has been great meeting with you and learning more about high-performance automobiles. " Amos Winter, words cannot really capture how much fun I have had and how much I have learned from you over the last ten years working together. I am sure my next job won't have quite the same adventures with my supervisor, assume we will not get stuck on skis across an international border, fly on a tiny airplane through Guatemala, and hopefully I will not lose any gas caps, but it has been a blast! Thank you for building and running a lab where you care about the students and demonstrate this continuously. As I have seen at MIT, this is not always the case, and I value the amount of time and care you put into each of your students, and their lives. I look forward to talking about engineering projects as we look for topics to work on together in the future, comparing notes on cars we own or want to buy, and updates on life and work. You are always welcome in MN! Thank you for your help getting everything together over the last few weeks, even with your hectic travel schedule. Congrats on tenure and I look forward to hearing about your exciting research projects in the future! " Thank you to my committee, Franco Cimatti, Maria Yang, and Sangbae Kim for your help and guidance through my PhD. Your insight and wisdom has helped me think about day-to-day issues and to shape my work and broaden the scope beyond designing for a single vehicle. " Thank you Jake Jurewicz, Guillermo Pamanes, Young Suk Jo, Patricia Yen, Joshua Siegel, and Chad Jacoby for the initial development of the first archi- tecture in MIT course 2.76 in Fall 2014. Having as many excellent engineers working on a project together and excited about the challenges is a fun place to be. " Thank you Sahil Shah, Victor Prost, Zackary Eubanks, Paige Reiter, Daria Bondarchuk, and Yu Hua for your work on the second architecture in MIT course 2.76 in Fall 2015. You took the first architecture and the challenges, and improved on it greatly, even when that seemed difficult at the time. 5 * In no specific order, thank you to Simone Gelmini, Shane Pratt, Kameron Conforti, Victor Prost, Sahil Shah, Charlie Wheeler, Dan Gilbert, Julia Sokol, Raghav Aggarwal, Josh Wiens, Murthy Arelekatti, Sebastian Ahling, Michael Buchman, and Tyler Hamer for your technical help with this project. All of you are good friends, and I value your willingness to help me through the challenges of a PhD. " Thank you Joe Teja and Jonathan Tong for your help with the patents. The late nights together and brainstorming about how to best describe my work were fun. Thank you for helping with patents with last minute notice, and for working around my ever changing schedule while finishing my PhD. * Thank you to my family for your support of me as a student starting as a child, and over the last eleven years at MIT. Thank you for everything you have and continue to do for me. I came to MIT with two suitcases and we are coming back with two moving trucks. I look forward to spending more time together now that I will be living closer to home. " Members of GEAR Lab, it has been great getting to know each of you. I have enjoyed working on projects, brainstorming together, traveling with you, and becoming friends. Thank you for putting up with my constant rearranging of lab, working on my car, and storage of stuff everywhere. I will miss the lab, but the people in lab I will miss the most. I look forward to keeping in touch in the future. • Thank you to all of the technical staff in the teaching spaces and shops at MIT. I have learned a lot from each of you and enjoyed spending time together talking about machines, manufacturing techniques, and gaining wisdom from you. I enjoy spending time working together on projects, and look forward to showing you my house shop if you are ever in town. Mark Belanger, I enjoyed working together, and learning to machine in Edgerton Student Shop, talking about machines, life, hobbies, and your family. Pat McAtamney, thank you for everything. It was fun working with you in LMP and the Area 51 shop. * Thank you to all of the students who have worked with me as UROPs. It has been fun getting to know you, learning more about you, and teaching you more about my research. " MIT MakerWorkshop thank you for your support of my research. The ability to machine in a shop where I can work in the evening, work together with peers, and have the ability to do what I need to get a project done is great. Thank you to all of the mentors, it has been great working together, creating new events and programs, and building a better space for students. I am also grateful to the following sources who have provided financial support for this work: 6 " The company partner, for providing funding for this work. " MIT Undergraduate Research Opportunities Program, for funding to cover the UROP students who worked with me. " National Science Foundation Graduate Research Fellowship Program, for the graduate fellowship to cover a portion of my tuition during my graduate work. " Mechanical Engineering, for a graduate fellowship for one semester during my PhD. 7 THIS PAGE INTENTIONALLY LEFT BLANK 8 Contents 1 Introduction 13 1.1 Background ........ ............. 13 1.2 Emissions Regulations Drive the Need for Hybridization 14 1.3 Types of Hybrids ..... ............. 14 1.4 Performance Hybrids. ... .......... 16 1.5 Dual Clutch Transmission .... ....... .. 17 1.6 Outline of thesis ... ... ...... ....... 20 2 A Framework and Case Studies for Designing Novel High-Performance Hybrid Transmissions 21 2.1 Minimum Part Count Design Framework .......... ...... 22 2.2 Two-Motor Clutchless Architecture . ........ ......... 28 2.2.1 Two-Motor Clutchless Architecture Prototype ....