Design, Implementation, and Testing of a High-Power Electrified

Design, Implementation, and Testing of a High-Power Electriﬁed Powertrain for an American Muscle Car DESIGN, IMPLEMENTATION, AND TESTING OF A

HIGH-POWER ELECTRIFIED POWERTRAIN FOR AN

AMERICAN MUSCLE CAR

BY ROBERT LAU, B.Tech.

a thesis submitted to the department of mechanical engineering and the school of graduate studies of mcmaster university in partial fulfilment of the requirements for the degree of Master of Applied Science

TITLE: Design, Implementation, and Testing of a High-Power Electriﬁed Powertrain for an American Muscle Car

AUTHOR: Robert Lau B.Tech., (Automotive & Vehicle Technology) McMaster University, Hamilton, Canada

SUPERVISOR: Dr. Ali Emadi

NUMBER OF PAGES: xvi, 126

ii Lay Abstract

Until recently, hybrid electric vehicles have tended to be available in a fairly limited market segment with few offerings for performance-oriented vehicle customers. The introduction of high performance hybrid vehicles suggests that this trend is likely to change. Increasingly more stringent fuel economy and emissions standards means that performance vehicle segments such as American muscle cars must adopt new technologies to retain their performance characteristics. Hybrid powertrains are one solution to providing and improving on the iconic performance of American muscle while meeting future regulatory changes. The addition of a number of electrified components to a gasoline powertrain can assist in achieving desired performance while reducing fuel economy. This thesis investigates the detailed design process adopted to make these modifications while maintaining the functionality expected by muscle car owners. After the design and assembly of the hybrid muscle car powertrain, a specific testing plan was laid out to ensure that the system is capable of sustaining the expected power output. This design and testing process can help introduce new hybrid vehicles to the market which are capable of meeting both the upcoming fuel economy regulations as well as the ongoing performance expectations of the muscle car market.

iii Abstract

This thesis outlines the design and implementation process of an electrified powertrain for use in an American muscle car. Designed as McMaster University’s entrant to the EcoCAR 3 Advanced Vehicle Technology Competition (AVTC), an electrified powertrain was developed to provide a Chevrolet Camaro with the performance expected by the American muscle car market while maintaining ever increasing fuel economy regulations. A background of current trends in vehicle electrification, including the prominent market segments experiencing these trends, will be explored along with the history of the classic and modern American muscle car’s technical specifications. Following an investigation into existing vehicle electrification trends, the selected hybrid architecture will be discussed. The process of converting a conventional combustion powertrain into a series- parallel hybrid electric powertrain will be explored from the component-level through to full system design. Following a review of the design process for the powertrain, a high-level testing plan will be proposed using a number of test cells available within the facility. This plan will begin at the component-level exploring specific areas of potential complication and move up to complete system-level testing of powertrain functionality.

iv Acknowledgements

This research was undertaken, in part, thanks to funding from the Canada Excellence Research Chairs (CERC) program,, the McMaster University Faculty of Engineering, General Motors (GM), the EcoCAR 3 Advanced Vehicle Technology Competition (AVTC), and the Natural Sciences and Engineering Research Council (NSERC). I would like to thank my supervisor, Dr. Ali Emadi, for giving me the opportunity to pursue this research and providing an insightful and enriching graduate experience. I would like to extend my sincere gratitude to members of the McMaster Formula Hybrid team and the McMaster Engineering EcoCAR 3 team for a remarkable four years. You have enriched my university experience far beyond my expectations and have helped ignite my passion for curiosity, learning, and discovery. Thank you to my colleagues and researchers at the McMaster Automotive Re- source Centre (MARC) for your guidance and support throughout my research, and to the machinists of JHE for supporting the development of our prototype vehicle. Finally, I would like to thank my parents, Astor and Anthony Lau, and my family and friends, for their continued encouragement throughout this incredible journey. This would not have been possible without you.

v Notation and Abbreviations

AVTC Advanced Vehicle Technology Competition

AWD All-Wheel Drive

BEV Battery Electric Vehicle

BSG Belt-driven Starter Generator

CAFE Corporate Average Fuel Economy

CERC Canada Excellence Research Chairs

CVT Continuously Variable Transmission

DOE Department of Energy

DOT Department of Transportation

ECM Engine Control Module eCVT Electronic Continuously Variable Transmission

EPA Environmental Protection Agency

ERS Energy Recovery System

vi EV Electric Vehicle

F1 Formula One World Championship

FIA Federation Internationale de l’Automobile

GHG Greenhouse Gas

GM General Motors

HESS Hybrid Energy Storage System

HEV Hybrid Electric Vehicle

HSD Hybrid Synergy Drive

HV High Voltage

HVAC Heating, Ventilation, and Air Conditioning

ICE Internal Combustion Engine

LMGTE-AM “Le Mans” Grand Touring Endurance - Amateur

LMGTE-PRO “Le Mans”Grand Touring Endurance - Professional

LMP1 “Le Mans” Prototype 1

LMP1-H “Le Mans” Prototype 1 - Hybrid

LMP2 “Le Mans” Prototype 2

LSD Limited Slip Diﬀerential

LV Low Voltage

vii MARC McMaster Automotive Resource Centre

MGU-H Motor Generator Unit-Heat

MGU-K Motor Generator Unit-Kinetic

NHRA National Hot Rod Association

NSERC Natural Sciences and Engineering Research Council

OEM Original Equipment Manufacturer

OPEC Organization of the Petroleum Exporting Countries

PHEV Plug-in Hybrid Electric Vehicle

RDU Rear Drive Unit rpm Revolutions per Minute

RS Rally Sport

RWD Rear-Wheel Drive

SS Super Sport

TCM Transmission Control Module

THS Toyota Hybrid System

VTS Vehicle Technical Speciﬁcations

WEC World Endurance Championship

viii Contents

Lay Abstract iii

Abstract iv

Acknowledgements v

Notation and Abbreviations vi

List of Tables xiii

List of Figures xiv

1 Introduction 1 1.1 Research Objective ...... 3

2 Existing High-Performance Electriﬁed Powertrains 6 2.1 Performance Car Classes ...... 6 2.2 Vehicle Electriﬁcation in Motorsports ...... 7 2.2.1 FIA World Endurance Championship ...... 8 2.2.2 FIA Formula One World Championship ...... 9 2.2.3 FIA Formula E Championship ...... 11

ix 2.3 Performance HEVs ...... 11 2.3.1 Ferrari LaFerrari ...... 12 2.3.2 McLaren P1 ...... 13 2.3.3 Porsche 918 Spyder ...... 13 2.4 Performance EVs ...... 14 2.4.1 Tesla Model S P100D ...... 15 2.4.2 Rimac Concept One ...... 16 2.4.3 Audi R8 e-tron ...... 16

3 American Muscle Cars 18 3.1 Class Deﬁnition ...... 18 3.2 History of American Muscle ...... 19 3.3 Modern Muscle Car Markets ...... 21 3.4 Modern Muscle Car Speciﬁcations ...... 22

4 Hybrid Electric Vehicle Architectures & Selected Powertrain Con- ﬁguration 26 4.1 Types of HEV Architectures ...... 26 4.1.1 Common Motor Position Nomenclature ...... 27 4.1.2 Series Hybrid Architecture ...... 29 4.1.3 Parallel Hybrid Architecture ...... 30 4.1.4 Power-Split Architecture ...... 31 4.1.5 Series-Parallel Architecture ...... 34 4.2 Selected Vehicle Architecture ...... 36 4.3 Powertrain Components ...... 38

x 4.3.1 GM LTG 2.0L Turbocharged Combustion Engine ...... 39 4.3.2 YASA P400 HC Electric Motor ...... 40 4.3.3 GM 8L90 Automatic Transmission ...... 41 4.3.4 Additional Driveline Components ...... 41

5 Powertrain Design 43 5.1 Goals & Limitations ...... 43 5.2 Integrated Starter/Generator (P1 Electric Motor) ...... 45 5.2.1 Chain/Belt Drive (P0) vs. Direct Coupling (P1) ...... 45 5.2.2 Crankshaft Coupling ...... 53 5.2.3 Coupling Failure & Proposed Modifications ...... 56 5.3 Combustion Engine Modifications ...... 58 5.3.1 Auxiliary Component Electrification ...... 59 5.3.2 Front Cover ...... 62 5.3.3 E85 Fuel Conversion ...... 62 5.3.4 Turbocharger Upgrade ...... 63 5.3.5 Dry Sump Oil Pan ...... 64 5.3.6 Belt Driven Oil Pump ...... 66 5.4 Clutch ...... 68 5.4.1 Flywheel ...... 68 5.4.2 Housing ...... 69 5.4.3 Actuation System ...... 72 5.5 Primary Traction Motor (P2 Electric Motor) ...... 73 5.5.1 Housing ...... 74 5.5.2 Motor Drive Shaft ...... 77

xi 5.6 Transmission & Driveline ...... 81 5.6.1 Prop Shaft ...... 82 5.6.2 Diﬀerential & Half Shafts ...... 82

6 Proposed Testing Plan 84 6.1 Electric Motor Testing (AVL Motor Dyno) ...... 85 6.2 Combustion Engine Testing (Horiba Dyno) ...... 86 6.2.1 Engine Start and Idling ...... 88 6.2.2 Integrated Starter/Generator ...... 89 6.2.3 Baseline Operation ...... 91 6.2.4 Turbocharger Upgrade ...... 91 6.2.5 E85 Fuel Maps ...... 92 6.2.6 Conﬁrm Modiﬁed Engine Parameters ...... 93 6.3 3-Axis Driveline Testing (A & D Driveline Dyno) ...... 93 6.3.1 Clutch Testing ...... 95 6.3.2 Speed Matching Logic ...... 96 6.3.3 Transmission Shifting ...... 96 6.3.4 Regenerative Braking ...... 97 6.4 Combined Driving Cycle Testing ...... 98 6.4.1 Investigating Power-Split Logic ...... 99

7 Conclusion 100

A Powertrain Mount Simulation Results 102

References 117

xii List of Tables

2.1 2016 World Endurance Championship LMP1-H Specifications . . . . 9 2.2 Performance HEV Technical Specifications ...... 12 2.3 Performance EV Technical Specifications ...... 15 3.1 2017 Ford Mustang Technical Specifications ...... 23 3.2 2017 Chevrolet Camaro Technical Specifications ...... 23 3.3 2017 Dodge Challenger Technical Specifications ...... 24 3.4 Top Muscle Car Performance Specifications ...... 25 4.1 HEVs Containing Power-Split Powertrains ...... 34 4.2 HEVs Containing Series-Parallel Powertrains ...... 36 5.1 Powertrain Mount Loading Conditions ...... 44 5.2 P1 Motor Loading Conditions ...... 52 5.3 Clutch Housing Loading Conditions ...... 70 5.4 Clutch Actuation Parameters ...... 73 5.5 P2 Motor Static Loading Requirement ...... 75 5.6 P2 Motor Loading Conditions ...... 77 5.7 P2 Shaft Stress Calculations ...... 80

xiii List of Figures

4.1 Motor Position Terminology ...... 27 4.2 Series HEV Architecture ...... 29 4.3 Parallel HEV Architecture ...... 31 4.4 Planetary Gear Set ...... 32 4.5 Toyota Hybrid Synergy Drive ...... 33 4.6 Series-Parallel HEV Architecture ...... 35 4.7 McMaster Engineering EcoCAR3 Camaro Powertrain ...... 37 4.8 McMaster Engineering EcoCAR3 Camaro Completed Powertrain . . . 38 4.9 GM LTG 2.0L Turbocharged Combustion Engine ...... 39 4.10 YASA P400 HC Electric Motor ...... 40 4.11 GM 8L90 8-speed Automatic Transmission ...... 41 5.1 Creaform HandySCAN 3D Scanner ...... 51 5.2 3D Scan (left, center) & Final Modified Design (right) ...... 52 5.3 Final Installation of Front Cover w/ P1 Electric Motor ...... 53 5.4 Modified Crankshaft (left) & P1 Motor Coupler (right) ...... 54 5.5 YASA P400 Temperature De-Rating Curves ...... 55 5.6 Modified Crankshaft with P1 Motor Coupler ...... 56 5.7 Failure of P1 Motor Coupler ...... 57

xiv 5.8 Davies Craig EWP115 Electric Water Pump ...... 60 5.9 Dry Sump Oil Pan ...... 65 5.10 Oil Sprocket Prototype (left), Oil Pump Belt (right) ...... 67 5.11 Custom Flywheel (left) & 2-Plate Clutch (right) ...... 69 5.12 Clutch Release Bearing (left) & Clutch Installed in Housing (right) . 71 5.13 Completed P2 Motor Housing Rear (left) & Front(right) ...... 76 5.14 Motor Drive Shaft Stress (left) & Topological Optimization (right) . . 78 5.15 Completed Motor Drive Shaft ...... 81 6.1 AVL DynoSpirit for e-Motor Testing ...... 85 6.2 Horiba Engine Test System ...... 87 6.3 Single A&D Dyno Unit ...... 94 A.1 Front Cover Longitudinal Loading - Constraints ...... 102 A.2 Front Cover Longitudinal Loading - Simulated Displacement . . . . . 103 A.3 Front Cover Longitudinal Loading - Simulated Von Mises Stress . . . 103 A.4 Front Cover Lateral Loading - Constraints ...... 104 A.5 Front Cover Lateral Loading - Simulated Displacement ...... 104 A.6 Front Cover Lateral Loading - Simulated Von Mises Stress ...... 105 A.7 Front Cover Vertical Loading - Constraints ...... 105 A.8 Front Cover Vertical Loading - Simulated Displacement ...... 106 A.9 Front Cover Vertical Loading - Simulated Von Mises Stress ...... 106 A.10 Clutch Housing Actuation Force - Constraints ...... 107 A.11 Clutch Housing Actuation Force - Simulated Displacement ...... 107 A.12 Clutch Housing Actuation Force - Simulated Von Mises Stress . . . . 108

xv A.13 Clutch Housing Actuation Force - Simulated Von Mises Stress (alternate view) ...... 108 A.14 Clutch Housing Static Installation Loading - Constraints ...... 109 A.15 Clutch Housing Static Installation Loading - Simulated Displacement 109 A.16 Clutch Housing Static Installation Loading - Simulated Von Mises Stress110 A.17 P2 Motor Housing Longitudinal Loading - Constraints ...... 110 A.18 P2 Motor Housing Longitudinal Loading - Simulated Displacement . 111 A.19 P2 Motor Housing Longitudinal Loading - Simulated Von Mises Stress 111 A.20 P2 Motor Housing Lateral Loading - Constraints ...... 112 A.21 P2 Motor Housing Lateral Loading - Simulated Displacement . . . . . 112 A.22 P2 Motor Housing Lateral Loading - Simulated Von Mises Stress . . . 113 A.23 P2 Motor Housing Vertical Loading - Constraints ...... 113 A.24 P2 Motor Housing Vertical Loading - Simulated Displacement . . . . 114 A.25 P2 Motor Housing Vertical Loading - Simulated Von Mises Stress . . 114 A.26 P2 Motor Housing Torque Converter Loading - Constraints ...... 115 A.27 P2 Motor Housing Torque Converter Loading - Simulated Displacement115 A.28 P2 Motor Housing Torque Converter Loading - Simulated Von Mises Stress ...... 116

xvi Chapter 1

Introduction

Since the advent of the internal combustion engine (ICE), the automotive industry has remained unchanged in its reliance on fossil fuels. Increasing public awareness of global climate change has prompted ever greater investigation into alternative fuel sources [1]. Greater public awareness of the impact of greenhouse gas (GHG) emissions caused by the personal transportation industry has seen governments and environmental regulatory bodies pushing the automotive industry to reduce fossil fuel consumption through the development of ever more stringent fuel economy and emissions regulations. These regulatory changes have resulted in an increase in the automotive industry’s research into improving overall vehicle efficiency as well as the development of alternative fuel vehicles. One solution to meeting the upcoming regulations is the improvement of vehicle fuel efficiency obtained through increased levels of vehicle electrification [2]. Traditionally, the car has been more than simply a means of transportation, with many owners having a very personal connection with their vehicle. Many buyers

1 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

choose their vehicle for a number of reasons, from utility; a work truck, to statements on fuel economy; the newest hybrid electric vehicle (HEV) or electric vehicle (EV), to status; a new luxury sedan, or simply for fun; a sports compact. Enthusiasts of various vehicle types often express themselves through their vehicles, making modifications to tweak them to their specific preferences. Until recently, this desire to express a personality through a vehicle has caused resistance to the widespread adoption of electrified vehicles. For the most part, the HEV market has only provided vehicles for those individuals valuing fuel efficiency and environmental responsibility. The market has had very few options for owners tending to prefer performance features and luxury. Taking part in EcoCAR 3, the current Advanced Vehicle Technology Competition (AVTC), the McMaster Engineering EcoCAR 3 team is working to electrify the powertrain of a Chevrolet Camaro, improving fuel economy while simultaneously offering the performance expected from an American muscle car. This effort, combined with recent HEV offerings in the high performance vehicle market, will go towards showing the public that electrified vehicles are not limited to the economy focused daily driver. The U.S. Department of Transportation (DOT) and U.S. Environmental Protec- tion Agency (EPA) have developed a schedule agreed upon by 13 automakers who make up 90% of vehicles sold in the United States to improve fuel economy targets up to the 2025 model year. This agreement outlines the annual Corporate Average Fuel Economy (CAFE) targets required for each automakers vehicle fleet with a projected target of 54.5 mpg by the 2025 model year [3]. These fuel economy targets will serve to both decrease the environmental impact of the automotive industry by limiting GHG emissions as well as reduce vehicle fuel costs and the reliance on oil imported

2 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

from Organization of the Petroleum Exporting Countries (OPEC).

1.1 Research Objective

This research project was completed in part due to McMaster University’s involve- ment in the EcoCAR 3 competition. The AVTCs program, sponsored by the U.S. Department of Energy (DOE), has partnered with the North American automotive industry since 1988 to provide realistic training scenarios for both graduate and un- dergraduate students interested in the automotive industry. Each competition series challenges a number of North American universities to incorporate advanced vehicle technologies and alternative fuels into donor vehicles to improve energy efficiency while maintaining the safety, performance, and customer acceptability of the vehicles. Launched in the fall of 2014, the EcoCAR 3 competition marked the 26th anniver- sary of the AVTC program. This iteration of the competition tasked 16 universities with replacing the powertrain of a 2016 Chevrolet Camaro LT with an electrified powertrain to meet future requirements for fuel efficiency while maintaining the mar- ketability of the vehicle. In order to achieve this, the performance of top level Amer- ican muscle cars were used as a benchmark for the competition vehicle while keeping in mind the projected fuel economy requirements of the future automotive market. The objective of this thesis was to design and assemble a powertrain capable of providing the performance expected from American muscle cars while maintaining the fuel economy targets outlined by the EcoCAR 3 competition. The McMaster Engineering EcoCAR 3 Team is developing the powertrain for Camaro E/28 to achieve these targets. The direct contributions to the Camaro E/28 vehicle powertrain as a result of this

3 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

research include the following topics:

1. Design of the P1 electric motor mounting and coupling system. 2. Combustion engine oil system modiﬁcation. 3. Electriﬁcation of auxiliary engine bay components. 4. Integration of a manual clutch pack for drive mode switching. 5. Design of the P2 electric motor mounting and coupling system. 6. Overall powertrain packaging. 7. Preliminary setup of assorted dynamometer test cells and development of high level testing plan for powertrain components.

Additional modifications to the vehicle driveline and fuel system mentioned throughout this thesis were made in cooperation with the McMaster Engineering EcoCAR 3 team and outside engineering companies but should be considered outside the scope of this research. This thesis begins with an investigation into the current state of the automotive market with regards to performance-oriented HEVs. This will include an overview of commonly used vehicle classifications along with their respective consumer market segments. This chapter also reviews the recent introduction of electrified vehicle technologies in various arenas of motorsport as well as a comparison of current performance HEVs and EVs. Following this, a history of the American muscle car as a vehicle class will be discussed. The origins of the vehicle class and terminology will be covered along with its evolution to the modern muscle car models. The current specifications for top performing modern muscle cars will be compared, providing benchmark performance figures for the proposed electrified powertrain.

4 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Various types of HEV architectures will be described next, including common architectures and their vehicle applications. This chapter also describes the benefits of each type of architecture and moves on to describe the particular architecture selected for the purposes of this research. This description will include specific powertrain components selected for this project. The next chapter will discuss, in detail, the design process used to develop the proposed powertrain. This will include discussion into the newly designed systems required to implement the two electric motors, as well as the required modifications ot the conventional powertrain used as a basis for this project. Upgrades to various stock components in order to support the additional power output of the powertrain will also be included. Finally, a high-level testing plan is outlined for the powertrain and each of its subsystems and components. This plan begins with testing at the component level for each major electrified powertrain component making use of a number of specialized dynamometer test cells part of the McMaster Automotive Resource Centre (MARC) facility. The testing plan increases in system complexity and scope and culminates in full powertrain testing including driving cycles and power-split logic.

5 Chapter 2

Existing High-Performance Electriﬁed Powertrains

2.1 Performance Car Classes

A wide array of vehicle classification schemes are defined by various parties involved in the automotive market. Organizations ranging from governmental bodies, vehicle manufacturers, and various consumer groups, have created classification conventions to aid in regulatory definitions, functional comparisons, and marketing and sales. A common classification scheme accepted by many consumers revolves around defining vehicles as a function of both size; indirectly related to passenger and cargo capacity; and power or performance. Generally, economy, mid-size, and sedan or full-size vehicles are classes used to describe various non-performance based vehicles. These classes of vehicles often produce enough power to comfortably drive at highway speeds, with less focus on dynamic driving capabilities such as rapid acceleration, braking, and heavy cornering, in exchange for improved comfort, fuel-efficiency, and

6 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

lower purchase prices and operating costs. The performance vehicle market also contains various generally accepted classes. This market also contains various sub-classes based on size and vehicle shape, such as the hot hatch, sport sedan, and coupe. Performance oriented vehicles are often also sold at higher price points, therefore overlapping luxury-based vehicle categories such as compact, mid-size, and full size executive vehicles. At the extreme end of performance vehicles, the supercar label is often given to luxury vehicles which exhibit very high performance characteristics, often built in limited quantities by automakers specializing in performance vehicles. These vehicles differ from consumer level performance vehicle models mainly by rarity and price. During recent times, the exclusive title hypercar has often been used to describe ultra-rare vehicles with performance exceeding that of even the supercar class. For the purposes of this thesis, the term supercar will be used collectively to refer to both supercar and hypercar class vehicles. The classes listed above are very vaguely defined, with class definitions, and even the classification of specific vehicles, changing based on market trends and the opin- ions of general consumers, review groups, and enthusiasts.

2.2 Vehicle Electriﬁcation in Motorsports

As with many automotive technologies which are currently commonplace, such as aerodynamic bodywork, rear-view mirrors [4], and disc brakes [5], electriﬁed powertrain technologies are being developed, tested, and improved in the world of motorsport. Top-tier international racing series overseen by Federation Internationale de l’Automobile

7 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

(FIA) such as the World Endurance Championship (WEC), Formula One World Championship (F1), and Formula E Championship, explore a wide range of vehicle electriﬁcation systems as they continue to push the boundaries of vehicle technology and strive to develop more fuel-eﬃcient and sustainable vehicles.

2.2.1 FIA World Endurance Championship

The WEC racing series overseen by the FIA is one of many international racing series with classifications involving hybrid vehicle technologies. This championship series includes 4 vehicle classifications ranging from production road-legal vehicles competing in the “Le Mans”Grand Touring Endurance - Professional (LMGTE-PRO) and “Le Mans” Grand Touring Endurance - Amateur (LMGTE-AM) classes, to prototype vehicles with no production minimum requirements in the “Le Mans” Prototype 1 (LMP1) and “Le Mans” Prototype 2 (LMP2) classes. Of these two prototype classes, LMP1 class vehicles have the option to compete in the “Le Mans” Prototype 1 - Hybrid (LMP1-H) class with integrated energy recovery systems (ERSs) [6]. In addition to physical vehicle dimension requirements, each “Le Mans” Prototype class contains regulations regarding minimum vehicle weight, fuel capacity, instanta- neous fuel flow rate, and fuel energy available per lap. The 2016 race season saw three constructors compete in the LMP1-H class, with Toyota, Porsche, and Audi each entering the endurance race series. With very similar specifications to each other, these prototype vehicles are some of the most powerful hybrids built by any vehicle manufacturer. The technical specifications for the vehicle entered by each LMP1-H competitor is shown in Table 2.1 [7, 8, 9]

8 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

While the FIA WEC facilitates the construction and testing of hybrid powertrain technologies, it also allows constructors to test their hybrid systems in demanding endurance situations, with vehicles pushed to performance limits for races ranging from 6 to 24-hour continuous driving events, with limited stops for tire changes, refueling, and vehicle repairs. Motorsport championships involving hybrid technologies, many of which limit total onboard fuel and electrical energy, also promotes the development of improved powertrain eﬃciency. The Audi WEC team, for example, has reduced the fuel consumption of the V6 ICE in the R18 by 32% since 2011, while simultaneously improving lap times by 3.8% [9]. Various improvements to energy recovery systems have also been made to further improve both vehicle eﬃciency and performance.

2016 WEC LMP1-H Vehicles Toyota Gazoo Porsche Audi Speciﬁcation TS050 Hybrid 919 Hybrid R18 Hybrid Engine Engine Type 2.4 L twin-turbo V6 2.0 L turbo V4 4.0 L turbo V6 Engine Power 368 kW 373 kW 378 kW Fuel Capacity 62.5 L 62.3 L 49.9 L Fuel Type Gasoline Gasoline Diesel Hybrid System Electric Power 368 kW 298 kW 350 kW Combined Power 736 kW 671 kW 728 kW Battery Lithium-ion Lithium-ion Lithium-ion Dimensions Length 4650 mm 4650 mm 4650 mm Width 1900 mm 1900 mm 1900 mm Height 1050 mm 1050 mm 1050 mm Min Weight 875 kg 875 kg 875 kg

Table 2.1: 2016 World Endurance Championship LMP1-H Speciﬁcations

2.2.2 FIA Formula One World Championship

The Formula One World Championship is another race series overseen by the FIA which includes hybrid technologies in each race vehicle. Unlike the WEC, with varying

9 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

vehicles classes competing in endurance races, the F1 series consists of a number of vehicles, each built to the same regulations, competing in a series of races to crown an annual World Driver Champion and World Constructor Champion. Since the early 2000s, a series of F1 regulation changes have progressively limited both the cylinder count and maximum engine displacement in an attempt to both limit engine power output and increase fuel economy. These progressions eventually led to the introduction of energy recovery systems to improve both overall vehicle efficiency and performance and has led to the development of current hybrid F1 power units. The 2006 race season saw an update to the engine specifications reducing the previous V10 3.0L displacement engine, to a V8 2.4L displacement engine. This reduction in engine size resulted in a loss of approximately 110kW (670kW V10 to 560kW V8) [10]. The 2014 season saw a further reduction in engine size from the 2.4L V8 engines to a significantly smaller 1.6L V6. In addition to the reduction in engine capacity, however, this race season introduced the inclusion of an ERS in the form of two electrified components to the vehicle. The motor generator unit-kinetic (MGU-K) and motor generator unit-heat (MGU-H) were systems designed by F1 constructors to recover and store energy from the car to be made available for vehicle propulsion or for the operation of any auxiliary systems for proper vehicle functionality [11]. The MGU-H is defined as an electric machine linked to the exhaust turbine of the engine turbocharger, while the MGU-K is defined as an electric machine mechanically linked to the vehicle drivetrain. These systems are intended to recover energy from the vehicle and supplement

10 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the mechanical power produced from the engine. The inclusion of the ERS led the Mercedes AMG Petronas F1 engineering team to achieve over 47% thermal eﬃciency in their 2016 F1 W07 Hybrid vehicle [12], compared with 29% thermally eﬃciency engines of the V8 F1 era.

2.2.3 FIA Formula E Championship

The Formula E Championship is the newest racing series overseen by the FIA and consists of formula-style, open wheel, electric-only vehicles. The series, started in 2014, has had stages of vehicle development to ensure proper electrical safety considerations are met. The ﬁrst season saw each team supplied with electric race vehicles built by a single manufacturer. Since then, additional constructors have been allowed to develop powertrains to place in a common chassis, with each vehicle having a limited power output of 170kW, although additional energy boosts are allowed given various race requirements designed to increase viewer engagement [13].

2.3 Performance HEVs

The global automotive market for high performance vehicles has seen a recent trend in the development of hybrid supercars for the consumer market. Vehicle manufacturers with a history of performance and luxury vehicle production such as Ferrari, Porsche, McLaren, and Mercedes-Benz, among others, have produced hybrid vehicles with supercar performance characteristics for the performance vehicle consumer market. The market segment looking to purchase vehicles from manufacturers such as Ferrari, Porsche, and McLaren, expect a certain level of performance and luxury. In

11 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

general, vehicles from these manufacturers are expected to perform in the supercar class, and the hybrid architectures selected by each manufacture reflect this. This section will investigate the vehicle specifications of existing HEVs, plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs) available on the luxury vehicle market. A technical specification table of some of the foremost performance HEVs is shown in Table 2.2 [14] followed by a more detailed description of each. The HEVs detailed below are considered the flagship hybrid supercars, with vehicles produced by Ferrari, McLaren, and Porsche. These three vehicles are very often compared in the automotive review and enthusiast industry and, with similar overall vehicle performance, present a good metric for the state of performance HEV and PHEV technology.

Vehicle Speciﬁcation Ferrari LaFerrari McLaren P1 Porsche 918 Spyder Hybrid Type HEV PHEV PHEV Engine Size 6.3 L V12 3.8 L twin-turbo V8 4.6 L V8 Engine Power 588 kW 542 kW 453 kW Electric Motor Power 120 kW 132 kW 213 kW Vehicle Power 708 kW 674 kW 661 kW Vehicle Torque 899 Nm 900 Nm 1279 Nm Battery Capacity 2.3 kWh 4.7 kWh 6.8 kWh Electric Range 0 km 10 km 29 km 0-100km/h 2.9 sec 2.8 sec 2.5 sec Top Speed 351 km/h 349 km/h 344 km/h Fuel Economy 16.8 L/100km 13.8 L/100km 10.7 L/100km Curb Weight 1255 kg 1547 kg 1675 kg

Table 2.2: Performance HEV Technical Speciﬁcations

2.3.1 Ferrari LaFerrari

The LaFerrari, Ferrari’s first hybrid vehicle, contains a parallel hybrid powertrain configuration with two electric motors with relatively limited power output. As Ferrari’s first foray into hybrid vehicle design, the LaFerrari has a limited level of electrification,

12 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

with the electric motors serving a very similar function to the F1 MGU-K system on which it is based. One electric motor is used for starter and generator functionality, while the other is used for regenerative braking and traction. The large V12 engine in the LaFerrari has a displacement of 6.3L and is capable of producing 588kW. With a 2.3kWh battery pack, the rear-wheel drive (RWD) LaFerrari is designed as fairly traditional supercar with no electric-only mode of operation (drive mode), with mild hybrid functionality; primarily regenerative braking and power assist, particularly low-end torque ﬁlling.

2.3.2 McLaren P1

The McLaren P1, like the LaFerrari, is a RWD hybrid supercar. The McLaren, however, has a single electric motor mounted to the engine to function as an engine starter motor and generator, and to provide both regenerative braking and tractive torque. With a signiﬁcantly larger 4.7kWh battery capacity [15] compared to the LaFerrari, the P1 can be driven in an electric only operation mode with a range of 10km [16]. The McLaren sits in the middle of the pack with regards to both weight, fuel economy, and power. With a greater level of electriﬁcation than the LaFerrari, and expected weight increase, likely due to additional battery storage, results, along with an improvement in fuel consumption.

2.3.3 Porsche 918 Spyder

The Porsche 918 Spyder is the last of the high-proﬁle hybrid supercars examined in this section. Unlike the Ferrari and McLaren, the Porsche 918 contains a parallel

13 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

all-wheel drive (AWD) hybrid powertrain conﬁguration, allowing it to achieve a sig- niﬁcantly better 0-100km/h acceleration time even though it is the heaviest vehicle of the three. The 918’s powertrain consists of an electric motor acting as a starter and generator, but also contains a second electric motor connected to the front wheels to provide AWD functionality. At 6.8kWh [17], the 918 has the largest battery capacity of the three hybrid supercars and resulting in the longest EPA electric only driving range of 19km .

2.4 Performance EVs

In addition to the development of hybrid vehicles in the supercar class, a number of automakers have also developed EVs capable of competing in the high performance classes of vehicles. Although this particular vehicle market is still in its infancy, a number of new companies focused on performance EVs are beginning to produce prototypes, along with some well-known production EVs. This section will investigate some of the production and prototype EVs with a focus on performance rather than purely energy efficiency. The technical specifications of a number of production EVs are presented in Table 2.3. Of the three EVs discussed in this section, the Rimac Concept One is the highest performance of the group. With performance numbers matching the supercar class vehicles produced by McLaren, Ferrari, and Porsche, and even conventional combustion vehicles, the Rimac is one of the few EV supercars. The Tesla Model S P100D and Audi R8 e-tron are more competitive in the performance luxury class vehicles, with lower power and top speed figures.

14 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Vehicle Speciﬁcation Tesla Model S P100D Rimac Concept One Audi R8 e-Tron Vehicle Power 507 kW 913 kW 340 kW Vehicle Torque 1072 Nm 1600 Nm 921 Nm Battery Capacity 100 kWh 90 kWh 90 kWh Range 507 km 350 km 450 km 0-100km/h 2.5 sec 2.5 sec 3.9 sec Top Speed 249 km/h 355 km/h 249 km/h Curb Weight 2219 kg 1900 kg 1841 kg

Table 2.3: Performance EV Technical Speciﬁcations

2.4.1 Tesla Model S P100D

The Tesla Model S may easily be the most well known production EV currently on the market. With aggressive performance and styling, the Model S has succeeded in making it clear to the public the ability of electric vehicles to compete with traditional combustion vehicles regarding range and performance. The performance based P100D’s 507km range and the more modest 100D’s 539km go to show that modern EVs can compete with the range of combustion vehicles [18]. Although the performance trim level of the Model S cannot compete with vehicles in the supercar class, it sits strongly within the performance luxury vehicle class. The newest trim level of the Model S, the P100D, contains a 100kWh battery pack powering an AWD system with a high-eﬃciency motor driving the front wheels and a high performance motor driving the rear [19]. The front electric motor produces 193kW and 276Nm while the rear motor produces 375kW and 712Nm, resulting in a total vehicle output of 507kW and 1072Nm. The Model S P100D’s two electric motors allow it to reach a top speed of 249km/h and accelerate from 0-100km/h in 2.5s [20, 21]. In addition to it’s impressive performance ﬁgures, the Model S is able to comfortably seat 5 adults, all with a price well within the range of luxury performance vehicles.

15 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

2.4.2 Rimac Concept One

The Rimac Concept One is a true supercar class EV. With limited production numbers and an electric AWD system producing 913kW and 1600Nm, the Concept One compares to the supercars discussed in section 2.3 very well [22]. The electric AWD system allows the Concept One to achieve a 0-100km/h acceleration time of 2.5 seconds which is comparable to the Model S [22]. The main diﬀerence between the Rimac and Tesla, however, come from the intended vehicle class and market. While the Tesla is designed as an aﬀordable luxury performance vehicle, the Concept One is targeted to the supercar market. With a limited production numbers and a two-seat design, the Rimac is in a separate vehicle class more focused on performance than practicality. It is more evident when comparing the range of each vehicle that the Rimac is built as an electric racecar more than the Tesla. With similar battery ca- pacities and weighing approximately 300kg less, the Rimac has a range of only 350km compared to the Tesla’s 507km.

2.4.3 Audi R8 e-tron

The short-lived Audi R8 e-tron is another performance EV which does not quite reach the performance characteristics of the HEV and PHEV oﬀerings from supercar manufacturers like Ferrari and McLaren, but remains competitive within the performance luxury class. Unlike the EV oﬀerings from Tesla and Rimac, the R8 e-tron was not built exclusively as an EV, but rather an EV variation built into a existing vehicle model, the Audi R8. In this regard, there are possible design limitations due to the nature of the particular EV development process. While the R8 e-tron produces a

16 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

relatively modest 340kW, the 921Nm torque output is higher than combustion vehicles of comparable power, as is characteristic of electric powertrains [23]. The RWD system results in an expectedly longer 0-100km/h acceleration time of 3.9 seconds when compared to the Tesla and Rimac discussed above, even though it is the light- est vehicle of the three at 1841kg [24]. The range of the R8 e-tron is a comfortable 450km driven by it’s 90kWh battery system [24].

17 Chapter 3

American Muscle Cars

3.1 Class Deﬁnition

The American muscle car is a vehicle class independent of the standard vehicle classes used in the automotive industry. While most vehicle classes are defined by governmental emissions regulating organizations such as Natural Resources Canada in the Fuel Consumption Guide publication [25], or the U.S. EPA’s Size Class guidelines [26], the American muscle car class is broadly defined by consumers and automotive enthusiasts. These standard size classes used by various government agencies often define vehicle classes based on total combined passenger and cargo volume [27]. While this utility-based class metric is effective at comparing the fuel efficiency options for vehicles affording the same capacity, separate performance and weight classes can help further define vehicle sizes for a number of consumers. American muscle cars are defined as affordable, intermediate sized (often 2-door sports coupes [28]) performance-oriented model, powered by large displacement V8

18 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

engines [29]. In addition to the intermediate-sized muscle car class, larger vehicles are often considered fullsize muscle cars, while smaller compact models are generally referred to as pony cars.

3.2 History of American Muscle

The Oldsmobile Model 88 powered by the Rocket V8 engine is often considered the ﬁrst muscle car. The “Rocket” 88 was built on the same relatively small and light chassis as the Oldsmobile Model 76 which was powered by a smaller inline 6 cylinder engine [30]. The combination of being built on the small and light Oldsmobile chassis of the Model 76 with a powerful, high-compression V8 engine helped the Rocket 88 win the majority of races in the inaugural 1949 NASCAR Strictly Stock series [31], and ultimately win the 1950 NASCAR Grand National Circuit [32]. Following the success of the Rocket 88 in the 1950 NASCAR season, the beneﬁts of combining a light chassis with a large, powerful engine were evident, and other manufacturers began developing vehicles using the same recipe. By the end of the 1950s, the automotive market saw the development of lightweight vehicles powered by large V8 engines like the Chrysler C-300, the Studebaker Golden Hawk, and the AMC Rambler Rebel. The formation of the National Hot Rod Association (NHRA) in 1951 led to an increase in the popularity of drag racing. With the introduction of more technical drag racing procedures in the 1960s, manufacturers such as Ford and Chrysler began developing vehicles with these competitions in mind [33].

19 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

The mid-1960s saw the production of smaller muscle cars, or “Pony cars” such as the Ford Mustang Boss and Shelby Mustang GT variants, along with the Chevrolet Camaro SS, and the Pontiac Firebird Trans Am. These smaller cars were ultimately cheaper to purchase than the offerings of their larger competitors. Many of these small muscle car models are the basis of the modern muscle car revivals. Although the muscle car manufacturers up to this point were effectively competing to produce the largest displacement engines with better peak power figures, the decline of the muscle car market began in the 1970s as a result of the OPEC oil embargo as well as newly developed regulations to limit vehicle emissions and air pollution [34]. This shift in the industry regulations saw the majority of auto manufacturers begin to focus on emissions control rather than simply power production. The oil embargo contributed to the shift in fuel availability in North American away from leaded fuels up to 100-octane, to a reduced 91-octane and the introduction of unleaded fuels [35]. This shift meant that higher compressions engines relying on high octane fuels to avoid pre-ignition would no longer function optimally on the new fuel restrictions. The recent addition of electrified vehicle technologies in a variety of motorsport arenas such as the FIA’s World Endurance Championship, Formula 1, and the recently introduced Formula E series, as well as an increasing trend of vehicle manufacturers producing hybrid vehicles with performance specifications in the supercar category, suggests that an introduction of hybrid technology into the muscle car segment is a natural progression.

20 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

3.3 Modern Muscle Car Markets

North American automakers have begun to revive the muscle car segment in recent years by bringing back notable muscle car models with aesthetics drawing inspiration from classic muscle car styling with a cleaner modern twist. In addition to these aesthetics, modern safety requirements and current combustion technologies such as higher compression ratios as well as waste heat recovery in the form of turbocharg- ers are often incorporated to provide both the power and efficiency required from performance vehicles to conform to progressively stricter emissions regulations. This revival comes at a time where many individuals capable of purchasing vehicles at the present have spent their childhood during the classic muscle car era. This generation grew up surrounded by the original muscle cars, often with parents or relatives who had a passion for vehicles. Due to the re-introduction of a number of modern classic muscle car models, the current generation has the chance to own the muscle car that they dreamed of as a child, or to relive days spent with the vehicle’s predecessor. Although the generation of middle aged or recently retired individuals is expected to be a large portion of the market for modern muscle cars, as a sub-class of the sports car category, many of the individuals likely to purchase sports cars in general will consider modern muscle cars due to their performance characteristics, power and weight figures, as well as the recent introduction of innovative vehicle technologies. Specifically, younger higher-income individuals who are relatively ambitious and career-oriented are found to be more likely to purchase sports cars [36]. These trends, combined with tendencies for higher-income households to purchase PHEVs and HEVs [37], suggest that there may be a growing market for hybrid muscle cars to

21 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the North American market, even given the additional costs of the newer electriﬁed power systems.

3.4 Modern Muscle Car Speciﬁcations

As of the mid-2000s, the modern muscle car market has comprised of a flagship vehicle from each major North American manufacturer: the Chevrolet Camaro, the Dodge Challenger, and the Ford Mustang. Of these three vehicles, only the Ford Mustang has been available continuously since it’s debut in 1965. The Mustang was developed by the Ford Motor Company as a concept car for both 1962 and 1963. Following the display of the concept Mustang models, Ford released the first generation production Mustang just weeks before the start of the 1965 model year releases. Despite the release of the competing Plymouth Barracuda two weeks prior, the popularity of the Mustang ultimately led to it’s attribution to the rise of the small muscle car movement and triggering the adoption of the term “pony car” [38]. The Mustang has since become one of the iconic American muscle cars, with a variety of trim levels to satisfy both budget conscious and performance oriented buyers. The current Mustang trim level specifications are shown in Table 3.1 [39]. The sixth generation Mustang, beginning with the 2015 model year, is available in a number of performance levels, with the top tier production Mustang, the Shelby GT350® producing 392 kW and 582 Nm, capable of a 0-100 km/h acceleration time of 4.3 seconds [40]. The first generation Chevrolet Camaro was released in 1967 as a direct competitor to the hugely popular Ford Mustang. With similarly aggressive styling, the Camaro

22 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

2017 Ford Mustang

Specification V6 EcoBoost® GT Shelby GT350® Engine Type 3.7 L V6 2.3 L turbo I4 5.0 L V8 5.2 L flat plane crank V8 Fuel Consumption City 12.8 L/100km 11.0 L/100km 15.6 L/100km 17.2 L/100km Highway 8.9 L/100km 7.9 L/100km 9.6 L/100km 11.3 L/100km Combined 11.0 L/100km 9.6 L/100km 12.4 L/100km 14.5 L/100km Peak Power 224 kW @ 6500rpm 231 kW @ 5500rpm 324 kW @ 6500rpm 392 kW @ 7500rpm Peak Torque 380 Nm @ 4000rpm 434 Nm @ 3000rpm 542 Nm @ 4250rpm 582 Nm @ 4750rpm Curb Weight 1898 kg 1885 kg 2030 kg 2066 kg Table 3.1: 2017 Ford Mustang Technical Specifications was released with a number of trim options to improve performance and appearance. The base Camaro could be upgraded with a variety of individual and package modifications including the Rally Sport (RS) appearance package, the Super Sport (SS) performance upgrades, as well as the now-iconic Z/28 race-inspired model [41]. The Chevrolet Camaro was temporarily discontinued after 2002, but was brought back as a 5th model generation in 2010. Currently in it’s sixth model generation, the 2016 Chevrolet Camaro is available in a number of trim levels outlined in Table 3.2 [42, 43]. While a Z/28 package has not yet been released for the 2017 Camaro, the top performing ZL1 trim performs well within the same bracket.

2017 Chevrolet Camaro Speciﬁcation LT LT V6 SS ZL1 Engine Type 2.0 L turbo I4 3.6 L V6 6.2 L V8 6.2 L V8 Fuel Consumption City 10.7 L/100km 12.4 L/100km 14.7 L/100km 16.8 L/100km Highway 7.6 L/100km 8.4 L/100km 9.4 L/100km 11.8 L/100km Combined 9.4 L/100km 10.7 L/100km 12.4 L/100km 14.7 L/100km Peak Power 205 kW @ 5600rpm 250 kW @ 6800rpm 339 kW @ 6000rpm 485 kW @ 6400rpm Peak Torque 400 Nm @ 3000-4500rpm 385 Nm @ 5300rpm 617 Nm @ 4400rpm 881 Nm @ 3600rpm Curb Weight 1515 kg 1558 kg 1671 kg 1761 kg Table 3.2: 2017 Chevrolet Camaro Technical Speciﬁcations

The Dodge Challenger experienced the longest hiatus of the three vehicles; having

23 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

been discontinued in 1983 until being brought back for a fourth generation in 2008. The Dodge Challenger was introduced by the Chrysler company as a branch from their previous muscle car offering, the Plymouth Barracuda. The first two generations of Chrysler’s muscle car was sold as the Barracuda, with an introduction of the Dodge Challenger for the 1970 model year [44]. At the time, the large engines offered in the Challenger, particularly the HEMI engines for which Dodge is known, were one the of main selling points. By the early 1970’s however, the decline of the muscle car movement meant that the Challenger would be discontinued shortly before being brought back in 2008. The fourth generation Dodge Challenger was brought back in 2008 during the reintroduction of modern muscle cars, most of which brought back retro styling inspired by the cars of the first muscle car movement. The various performance levels of the current Dodge Challenger are listed in Table 3.3 [45, 46, 47, 48, 49].

2017 Dodge Challenger Speciﬁcation SXT R/T SRT SRT Hellcat Engine Type 3.6 L V6 5.7 L HEMI V8 6.4L HEMI V8 6.2 L super HEMI V8 Fuel Consumption City 12.4 L/100km 15.7 L/100km 16.8 L/100km 18.1 L/100km Highway 7.8 L/100km 10.2 L/100km 10.2 L/100km 11.2 L/100km Combined 10.2 L/100km 13.1 L/100km 13.8 L/100km 14.7 L/100km Peak Power 227 kW @ 6350rpm 277 kW @ 5200rpm 362 kW @ 6100rpm 527 kW @ 6000rpm Peak Torque 363 Nm @ 4800rpm 542 Nm @ 4400rpm 644 Nm @ 4200rpm 881 Nm @ 4000rpm Curb Weight 1766 kg 1901 kg 1941 kg 2018 kg Table 3.3: 2017 Dodge Challenger Technical Speciﬁcations

Given that the modern muscle car models available from each manufacturer can range from the pony car performance range up to the more powerful muscle car category, the performance trim levels of each model were used to determine the target vehicle specifications for the hybrid muscle car designed for this project. The top performance specifications for each major muscle car offering are outlined

24 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

in Table 3.4 along with the target specifications for the hybrid muscle car powertrain. Overall performance specifications of the electrified powertrain were selected to remain competitive with the top performance levels of each production vehicle, with an additional goal of improving overall fuel economy. Given that the vehicle chassis which is to house the electrified powertrain is a 2016 Camaro, the top performance Camaro available at project outset, the 2015 Z/28 Camaro, was used as a target performance benchmark. The powertrain technical specifications were set to compete against the benchmark vehicle, with components selected to produce the desired results, while maintaining overall curb weight below the maximum limit supported by the 2016 Camaro chassis.

Performance Muscle Car Specifications Ford Mustang Chevrolet Camaro Dodge Challenger Target Powertrain Specification Shelby GT350® ZL1 SRT Hellcat PHEV Engine Type 5.2L flat plane crank V8 6.2L V8 6.2L super HEMI V8 2.0L turbo I4 Fuel Consumption City 17.2 L/100km 16.8 L/100km 18.1 L/100km 9.4 L/100km Highway 11.3 L/100km 11.8 L/100km 11.2 L/100km 7.8 L/100km Combined 14.5 L/100km 14.7 L/100km 14.7 L/100km 8.7 L/100km Peak Power 392 kW 485 kW 527 kW 447 kW Peak Torque 582 Nm 881 Nm 881 Nm 1000 Nm 0-100km/h 4.3 sec 3.5 sec 3.6 sec 4.0 sec Top Speed 282 km/h 319 km/h 320 km/h 320 km/h Curb Weight 2066 kg 1761 kg 2018 kg 1890 kg Table 3.4: Top Muscle Car Performance Specifications

25 Chapter 4

Hybrid Electric Vehicle Architectures & Selected Powertrain Conﬁguration

4.1 Types of HEV Architectures

At its root, the electrification of a powertrain can be described as either a series or parallel flow of electrical and mechanical energy. Broadly speaking, the power flow of hybrid vehicles can be described by one of the two configurations, or as a combination of both. In practice, hybrid vehicle powertrains have been designed to address a wide range of vehicle markets, ranging from fuel-economy based subcompact vehicles, to transport trucks, to alternative fuel public transportation. The complexity of the systems along with the flexibility of how to manage power flow is selected based on the required fuel economy, emissions management, and performance demanded by each vehicle’s particular market.

26 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

4.1.1 Common Motor Position Nomenclature

With a number of potential positions to place an electric motor into a powertrain, a naming convention has been adopted to communicate the topological position of electric motors in a given HEV powertrain. Generally, the position designations P0 through P4 are used to indicate the position of the motor [50]. A block diagram illustrating the motor positions is shown in Figure 4.1.

Engine Clutch RDU P3 Transmission P2 P1

P0 P4

Figure 4.1: Motor Position Terminology

The P0 position indicates a belt-driven starter generator (BSG), operating mainly as an ICE starter motor and generator unit with limited torque and power capability. Due to the belted connection rather than a direct shaft connection to the ICE crankshaft, the BSG is often a high speed electric motor with a speed ratio incorporated in the belt interface [50]. The P1 motor position describes a crankshaft mounted motor. Due to the direct

27 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

connection to the ICE crankshaft, the motor is limited to the maximum speed of the ICE, generally around 7000rpm [50]. This motor can, however, often be a higher power motor than one typically installed in the P0 position due to the lack of belted connection. It is important to note that the P0 and P1 designations refer to the differentiation of motor coupling to the ICE, rather than its position forward or aft of the engine. A direct drive electric motor connected to the front of the ICE is still referred to as a P1 electric motor. The P2 motor position indicates a motor connected to the transmission/gearbox input. A motor in the P2 position is often separated from the ICE by a clutch which can be opened under various operating modes (e.g. ICE starting). The P3 position is similar to the P2 motor position, but connected to the transmission output rather than input. This position also limits the speed of the motor, however in this case to that of the vehicle drive shaft. The P3 position may be beneficial in that efficiency losses through the transmission are avoided as the motor power is sent directly to the final drive unit of the vehicle. Finally, the P4 position indicates a motor connected directly to the wheel axles or half shafts, hence often referred to as “axle drive” motors. This motor position requires an electric motor mounted to each driven axle. Vehicles containing motors in the P4 position may make use of high speed motors with a gearbox used to reduce the motor speed to usable wheel speeds.

28 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

4.1.2 Series Hybrid Architecture

A series hybrid vehicle uses an electric motor as the sole source of tractive power. An ICE is used only as the input portion of a generator assembly to maintain battery charge. The lack of mechanical connection between the ICE and wheels results in one of the main beneﬁts of a series hybrid vehicle topology; the engine is able to operate at peak combustion eﬃciency as its operating point is independent of vehicle speed. Figure 4.2 illustrates a schematic outlining the components as well as the type of energy transfer between components.

Fuel Mechanical Electrical

(

10 Tank

Fuel Fuel

gal Engine

)

Electric Motor

Transmission YASA

RDU Transmission Motor400

Generator

Battery

Figure 4.2: Series HEV Architecture

With the engine able to operate at its most eﬃcient point, the conversion of energy stored in the form of fuel into electrical energy stored in the battery can be optimized.

29 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

The energy stored in the battery is then transformed back into mechanical energy by the drive motor when required. This serial energy transfer creates one of the drawbacks of this hybrid topology. The two-stage energy conversion from the ICE to the generator, and again from the generator to the electric motor, causes additional energy losses [51]. Another beneﬁt of a series HEV topology, however, is the simplicity of control. Because the ICE is controlled independently to the traction motors, the power ﬂow analysis is fairly straightforward resulting in simpler control system requirements [52].

4.1.3 Parallel Hybrid Architecture

Unlike the series vehicle topology, the parallel vehicle topology has both the ICE and electric motor mechanically connected to the wheels of the vehicle. The vehicle can therefore be driven solely by the ICE, the electric motor, or by a combination of the two. A schematic illustrating the component connections in a parallel HEV is shown in Figure 4.3. With more flexibility in the distribution of tractive force, selections can be made to have the required output shared amongst the ICE and motor to maximize overall energy efficiency. This topology also solves the multi-step energy conversion issue caused by a series power flow by limiting energy conversion to a single stage for tractive force, reducing energy losses due to conversion [51]. One drawback resulting from this flexibility, however, is the need for a more complex control system [53]. The parallel hybrid architecture is often selected when designing vehicles optimized for performance rather than fuel economy. With a mechanical connection from both the ICE and electric motor to the wheels, the motor can both supply tractive

30 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Fuel Mechanical Electrical

(

10 Tank

Fuel Fuel

gal ) Engine

RDU Transmission

Motor

Battery

Figure 4.3: Parallel HEV Architecture force, as well as provide additional load to the ICE to shift the operating point towards the most eﬃcient range.

4.1.4 Power-Split Architecture

The power-split hybrid architecture is often used in vehicles focused less on performance but rather on fuel eﬃciency. This type of hybrid system involves the inclusion of a planetary gearset into the transmission system. This gearset splits the power produced by the combustion engine into two distinct paths, a mechanical ﬂow coupled directly to the rear drive unit (RDU) and therefore the wheels of the vehicle, and an electrical path incorporating an electric motor/generator and battery system

31 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[52]. A planetary gearset consists of an inner sun gear and outer ring gear, mechanically connected via a set of planet gears mounted to a carrier. The assembly of sun gear, planet carrier, and ring gear, are able to rotate concentrically about a common axis. The nature of the gearset means that controlling any two inputs will dictate the output of the third component. A power-split HEV can therefore provide continuously variable transmission (CVT) functionality in the form of an electronic continuously variable transmission (eCVT) by continually varying one or more of the inputs to the planetary gearset rather than by varying pulley diameters as in a conventional CVT.

Ring Gear

Sun Gear

Planets & Planet Carrier

Figure 4.4: Planetary Gear Set

A power split hybrid sees each of the elements of the planetary gear set connected to one of two electric motors, or the ICE. While a number of commercially available HEVs have been based around a power-split hybrid system, the Toyota Hybrid System (THS) was one of the ﬁrst; successfully used in the ﬁrst generation Toyota Prius. The THS has since been renamed the Hybrid Synergy Drive (HSD) system as Toyota now uses the hybrid architecture in a number of non-Toyota vehicles. Figure 4.5 illustrates

32 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the topology of the Toyota HSD.

Electric Motor 1 S Engine C Output R Electric Motor 2

Figure 4.5: Toyota Hybrid Synergy Drive

The HSD makes use of a planetary gear set to connect the ICE and generator and traction motors. The ICE is connected to the planet carrier, C, while the generator and traction motors are connected to the sun gear, S, and the ring gear, R, respectively. In a power split system like this, engine power diverted through the mechanical connection goes directly to the vehicle final drive. The remaining power produced by the ICE is transferred through the electrical path to one of the motor/generator units, which converts it to electricity. From there the electrical energy can be stored in the on board battery system or transferred directly to the main traction motor [52]. The functional properties of the planetary gear set allow the ICE speed to be continuously varied with respect to the vehicle wheel speed via changes to the third component of the gearset, allowing the ICE to operate in an optimally efficient range. A number of more complex hybrid systems employ a power-split architecture to achieve very high fuel efficiency and emissions targets, including some of the more recent Toyota HEV systems. Table 4.1 outlines some of the technical specifications of power-split hybrids on the consumer vehicle market [54].

33 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Speciﬁcation Vehicle Class Engine Engine Main Electric Battery Production Model Size Power Motor Power Capacity Model Years Compact Toyota Prius 1.5 L 57 kW 50 kW 1.3 kWh 2000-2009 Lexus CT200h 1.8 L 73 kW 60 kW 1.3 kWh 2011- Mid-size Toyota Prius 1.8 L 73 kW 60 kW 1.3 kWh 2010- Toyota Avalon Hybrid 2.5 L 116 kW 105 kW 1.6 kWh 2013- Lexus ES300h 2.5 L 116 kW 105 kW 1.6 kWh 2013- Lincoln MKZ Hybrid 2.0 L 105 kW 88 kW 1.4 kWh 2011- Large Ford Escape Hybrid 2.5 L 99 kW 70 kW 1.8 kWh 2005-2012 Lexus RX400h 3.3 L 155 kW 123 kW 1.87 kWh 2006-2009

Table 4.1: HEVs Containing Power-Split Powertrains

4.1.5 Series-Parallel Architecture

The series-parallel architecture is an alternative to the power-split architecture when requiring multiple operating modes. A series-parallel powertrain contains an ICE with a direct mechanical connection to the output shaft of the vehicle via a clutch. This clutch, when disengaged, mechanically uncouples the ICE from the wheels. This clutch, working in conjunction with a minimum of two electric motors, allows the vehicle to eﬀectively operate in both series and parallel architectures. Figure 4.6 illustrates a layout of a RWD series-parallel HEV powertrain. Motor 1 is permanently coupled to the ICE, while Motor 2 is permanently coupled to the wheels. In this conﬁguration, each motor can serve a number of purposes corresponding to each of the vehicle’s modes of operation. Motor 2 acts primarily as as traction motor, but can also function in generator mode when regenerative braking is employed. Motor 1 can serve as an engine starter motor during ICE start conditions, a generator during series operation, and even as a traction motor when the powertrain is operating in parallel mode. The clutch separating the two motors serves to connect and disconnect the ICE/generator components from the transmission to

34 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Fuel Mechanical Electrical

(

10 Tank

Fuel Fuel

gal )

Clutch Engine RDU Transmission Motor 2 Motor 1

Battery

Figure 4.6: Series-Parallel HEV Architecture allow for both series and parallel operation. This powertrain configuration has three main modes of operation. With the clutch engaged, the vehicle can operate in series-parallel mode, with both the electric motors and ICE providing power to the wheels in a parallel power flow. The motor connected to the engine can provide tractive force, for true parallel powertrain operation, or can be placed into generator mode to increase the ICE operating point to a more efficient region. With the clutch disengaged, the ICE/generator components are separated from the traction motor and two different operating modes are available. Series hybrid mode can be used with the ICE/generator turned on and generating power for the battery or directly to the traction motor.

35 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

With the ICE turned off, the vehicle can also operate in electric-only mode, with only the traction motor functional. Due to the relatively greater level of electrification used in a series-parallel powertrain due to a requirement of two motors with one relatively strong traction motor, fewer HEVs use this powertrain topology. Table 4.2 lists some of the limited offerings on the current automotive market [54].

Speciﬁcation Vehicle Class Engine Engine Main Electric Battery Production Model Size Power Motor Power Capacity Model Years Compact BMW i8 1.5 L 170 kW 98 kW 7.1 kWh 2014- Mid-size Toyota Prius PHEV 1.5 L 57 kW 50 kW 4.4 kWh 2012- Ford C-MAX Energi 2.0 L 63 kW 111 kW 6.1 kWh 2013- Honda Accord PHEV 2.0 L 102 kW 124 kW 2.0 kWh 2014- Large Porsche Panamera S E-Hybrid 3.0 L 245 kW 70 kW 9.4 kWh 2014-

Table 4.2: HEVs Containing Series-Parallel Powertrains

4.2 Selected Vehicle Architecture

The powertrain ultimately selected for use in the Camaro E/28 was built upon vehicle technical speciﬁcations (VTS) set out by the EcoCAR 3 competition organizers. The minimum and target VTS as outlined by the competition were used as a baseline when generating vehicle model simulations to select the particular powertrain. The VTS selected for the vehicle achieved similar energy and fuel consumption levels laid out by the competition while also meeting the performance targets set out by the McMaster Engineering EcoCAR 3 team. Given that the goal of this particular project was to design a performance hybrid

36 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Fuel Mechanical Electrical

(

10 Tank

E85 Fuel

gal )

Tilton Clutch 2.0L Turbo YASA YASA LSD 8L90 P400 P400

HESS

Figure 4.7: McMaster Engineering EcoCAR3 Camaro Powertrain powertrain in line with the expectations of the American muscle car market, a series- parallel architecture was selected to achieve the performance desired from the vehicle. The selection of a P1-P2 PHEV architecture shown in Figure 4.7 allows the resulting powertrain to operate in a fuel-efficient mode with enough power for regular driving conditions. The desired efficiency can be achieved while operating mainly in electric- only or series mode. When desired, however, the drive mode can be switched to a parallel mode to provide additional power and torque to satisfy performance driving requirements, using the ICE and both electric motors to provide tractive force. The powertrain configuration selected for the Camaro is illustrated in Figure 4.7 while the completed powertrain is shown in Figure 4.8.

37 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 4.8: McMaster Engineering EcoCAR3 Camaro Completed Powertrain

4.3 Powertrain Components

In order to achieve the target vehicle speciﬁcations outlined in chapter 3, focus was placed on selecting components which would provide the maximum performance output at minimum packaging cost, with particular interest taken to physical packaging volume and power density. The components considered for the powertrain were examined during research conducted by Joel Roeleveld and the McMaster Engineering EcoCAR 3 team using a model-based analysis. The components ultimately selected for the hybrid muscle car powertrain will be discussed below. Roeleveld’s thesis: “On the Electriﬁcation of the American Muscle Car: An Analysis and Model Based Design” can be referenced for further information regarding the component selection process [55].

38 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

4.3.1 GM LTG 2.0L Turbocharged Combustion Engine

The stock vehicle used for this project contained a General Motors (GM) LGX V6 engine capable of producing 250kW and an 8-speed automatic transmission. This powertrain was removed and the system replaced with the newest Ecotec offering from GM, the 2.0L turbocharged I4 engine known as the LTG, shown in Figure 4.9. The turbocharger used on the ICE contains a twin-scroll exhaust flow design to reduce turbo lag and serves to create a wide power band for the engine. The selection of a turbocharged 4 cylinder engine to replace the stock naturally aspirated V6 engine was made in order to satisfy both the power and fuel economy targets defined for the vehicle. A turbocharged engine can provide the fuel economy of a smaller displacement engine when low power is demanded, but can also provide the output required under high power demand situations [56].

Figure 4.9: GM LTG 2.0L Turbocharged Combustion Engine

The engine was also outﬁtted with an upgrade kit from Vermont Tuning containing a new turbocharger with larger turbine and compressor wheels as well as a conversion to operate on E85 fuel. The turbo and fuel kit, along with a matching engine tune

39 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

provided as part of the upgrade package, allows the engine to increase power output to 291kW, an increase of almost 30% over the stock 205kW [57].

4.3.2 YASA P400 HC Electric Motor

In addition to the modiﬁed ICE, two YASA P400 HC electric motors were selected for the P1 and P2 positions, each capable of producing a continuous 90kW at the 400V nominal operating voltage of the vehicle’s hybrid energy storage system (HESS) [58]. These motors were selected in part due to their compatibility with the chosen ICE, as both share a peak speed of approximately 7000rpm, making them optimal to be connected pre-transmission in the P1 and P2 positions.

Figure 4.10: YASA P400 HC Electric Motor

The -HC variant of the YASA P400 motor, shown in Figure 4.10 was selected due to its additional cooling capability when compared to the P400 S and C models. With a liquid cooled stator and air cooled rotor, the -HC provides the greatest power output for the P400 line.

40 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

4.3.3 GM 8L90 Automatic Transmission

The GM Hydra-Matic 8L90 transmission, shown in Figure 4.11, is an electronically controlled eight-speed automatic transmission used in a number of RWD and AWD vehicles. From the same transmission family, the 8L45 eight-speed automatic in the stock vehicle powertrain was removed and replaced with the 8L90 model due to the increased maximum torque capacity of the 8L90’s torque convertor.

Figure 4.11: GM 8L90 8-speed Automatic Transmission

4.3.4 Additional Driveline Components

In order to add series-parallel functionality to the system, a Tilton Engineering, Inc. 2-plate racing clutch was selected for its compact size and ability to handle the 1000Nm maximum torque output of the powertrain. Situated between the P2 electric motor and the ICE, the clutch enables the powertrain to switch operating modes between electric-only and series operation, and parallel and series-parallel operation. With the clutch disengaged, the ICE/generator unit is physically disconnected from

41 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the P2 motor and transmission input, allowing the vehicle to operate in an electric- only drive mode using only the P2 motor, or in series mode, with the ICE/generator unit operating. With the clutch engaged, the powertrain can operate in parallel or series-parallel mode, with both YASA P400 motors and the ICE providing tractive force, or with battery charging capabilities. Finally, the two-piece drive shaft in the stock vehicle was replaced with a larger diameter, single piece driveshaft, as well as an upgrade to larger diameter half shafts, all capable of handling the increased torque produced by the series-parallel powertrain. The open RDU was also replaced with a limited slip model to provide increased performance characteristics under aggressive driving conditions.

42 Chapter 5

Powertrain Design

This chapter examines the various modiﬁcations and additions made to a conventional combustion engine powertrain in order to achieve both the power requirements demanded by the high-end American muscle car market while maintaining the fuel economy targets of a more modest vehicle. Thermal and structural simulations will be discussed for components which were designed or modiﬁed in order to complete the powertrain.

5.1 Goals & Limitations

The EcoCAR 3 competition organizers presented a list of minimum and target VTS for all competing vehicles as part of the competition rules. The VTS includes performance metrics such as acceleration times, passing time, minimum braking distance, lateral acceleration limits, and maximum curb mass, as well as a number of measures of fuel consumption and emissions. Given the competition target VTS, the McMaster Engineering EcoCAR 3 team

43 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

developed a powertrain capable of meeting the fuel consumption and both electric and overall range of the competition target VTS, while maintaining the increased performance specifications expected from an American muscle car. A number of structural areas of the vehicle chassis were outlined to be off limits to any modifications by EcoCAR 3 teams. These areas were selected to ensure that the performance of safety-critical systems of the vehicle such as crash sensors and physical protection in the form of crumple zones and crash bars retain their intended functionality. Aside from crash structures, limitations were placed on which components of steering and suspension were allowed to be modified, and to what extent, to ensure that vehicle dynamics performance is not compromised. With a pre-determined component list consisting of two electric motors, a combustion engine, manual clutch pack, and transmission, the major design requirements were to effectively mount all components within the provided vehicle space with little to no structural modifications on the part of the vehicle chassis. This ensures that any crash-worthiness of the stock vehicle remains as designed by the original equipment manufacturer (OEM).

Direction Longitudinal Lateral Vertical Load Case 20g 20g 8g Safety Factor 1.5 1.5 1.5

Table 5.1: Powertrain Mount Loading Conditions

The competition organizers outlined minimum load case requirements to be used when designing and simulating the mechanical strength of mounting structures for powertrain components. These testing values are listed in Table 5.1. Each powertrain

44 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

mount was required to be designed to withstand the loading conditions listed along with the additional safety factor without entering the region of plastic deformation.

5.2 Integrated Starter/Generator (P1 Electric Mo-

tor)

Of the two electric motors, one was permanently coupled to the combustion engine. This electric motor served to replace the starter motor on the conventional combustion powertrain as well as operating as a generator in select drive modes. In addition to its function as both a starter motor and generator, under signiﬁcant torque request situations, this motor can act to add additional tractive power to the system, limited by the power available from the onboard HESS, as well as the torque capacity of the selected transmission components.

5.2.1 Chain/Belt Drive (P0) vs. Direct Coupling (P1)

The ﬁrst design consideration made in the mounting process of the fore electric motor was to determine the relative position of the motor to the combustion engine. One option to package this motor was to have the motor mounted oﬀset to the engine in a P0 motor position described in section 4.1.1, with parallel rotational axes mechanically coupled to the crankshaft using a belt or chain drive. The other possibility was to mount the motor body directly to the engine, with a common rotational axis for both the motor and engine to simplify the power transmission path. These mounting options were considered in terms of both mechanical robustness as well as space limitations within the engine bay of the vehicle chassis.

45 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Generally, the option to mount the engine with a parallel, offset axis, allows for more flexibility in mounting positions as the motor can be placed relatively distant from the engine and be coupled through a flexible belt or chain drive system. A direct-mount motor, however, suggested a simpler design involving fewer power transmission components to fully couple the motor and engine, at the tradeoff of increased overall powertrain length. An axially aligned motor also allowed for the use of a pancake motor geometry like the selected YASA motor, while a belt driven method would require the use of a longer, narrower motor to satisfy packaging limitations. In order to assess the feasibility of each option, as well as to assist in the final selection of mounting position, a full list of projected modifications and potential failure points was compiled for each mounting method and compared.

Parallel Axis - Required Modiﬁcations

Custom drive pulley Robust mounting bracket for motor to chassis Custom spline shaft for motor (w/ integrated belt/chain sprocket) Belt/chain guides and tensioner

Parallel Axis - Expected Complications

Belt/chain power limitation, failed belt or chain Complex packaging solution for large number of components Additional bending load on motor and engine shafts

Axial Mounting - Required Modiﬁcations

Mounting bracket to interface with both electric motor and engine front

46 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Motor to crankshaft coupling shaft

Axial Mounting - Expected Complications

Extended powertrain length, reduced packaging ﬂexibility Strength of coupling (crankshaft snout not designed for high load transfer)

The option to mount the electric motor in the P0 position and attach a belt drive system posed more design and manufacturing requirements as well as a more extensive list of potential complications. Of the decision to use a belt or chain drive, a belt drive would have been selected to minimize noise and lubrication requirements. In order to integrate the forward electric motor in this fashion, a custom drive pulley would be required to replace the stock crank pulley. The stock pulley, designed for use with a v-belt, has significant potential for slippage and power loss under high loads. This requires that a custom pulley be designed to interface with the taper and keyed crankshaft snout. In addition to this drive pulley, a splined shaft is required to interface with the through-hole drive hub of the electric motor with sprocket geometry to match the drive belt profile. Due to the through hub nature of the YASA motor selected for the application, the inclusion of the motor driveshaft shaft would require an additional mounting system containing bearings to support the motor shaft on both sides of the motor. With the belt interfaces addressed, a tensioner and guide system would also be required to ensure that the belt tracks properly and is under sufficient tension to effectively transmit power. Finally, a mounting bracket would be required to fasten the electric motor to

47 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

a suitably strong portion of the vehicle chassis. The mounting point on the vehicle body as well as the mounting bracket must be robust enough to support the significant weight of the electric motor under normal driving conditions as well as against the reaction forces resulting from the motor drive, which can approach a maximum torque of 400Nm. Given the extensive list of design tasks required to achieve effective motor mounting in the belt driven motor position, a significant list of potential complications arises. A failure of the drive belt would result in non-catastrophic failure of the drive system, as only partial loss of vehicle functionality would occur. Drive modes would become limited if failure were to occur while the vehicle is operating as the series hybrid operation becomes impossible. The vehicle would be limited to electric-only and parallel drive modes, with battery charge regeneration limited to regenerative braking. Aside from belt failure, another complication of this design is the complexity of packaging the numerous components required to create the belt drive and tensioning system. Although belt failure and packaging difficulties are issues which can be addressed and mitigated, the final expected complication indicated that an axially aligned motor is preferred. Communications with the University of Victoria EcoCAR 2 design team showed that a similar decision to mount an electric motor parallel to the engine crankshaft driven by a belt system led to multiple catastrophic failures of the coupling mechanism [59]. An initial design resulted in a sheared shaft key rendering the system inoperable. In an attempt to address this issue, a larger keyway was cut into both the crankshaft

48 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

snout and mating pulley to increase key shear strength. In this case, the key did not fail, but resulted in a catastrophic failure of the crankshaft within the engine block, along with a fracturing of the timing sprocket. A final design was attempted using a tapered crankshaft snout mating with a matching tapered seat in the crankshaft pulley. This connection method was statically tested by applying the maximum output torque of the electric motor to the pulley and passed under test conditions. This design also ultimately failed when a belt drive was applied to the pulley. Based on this report, it was expected that although the crankshaft and connection method were sufficiently strong to support the theoretical maximum torque of the electric motor, the bending moment applied by the drive belt under significant tension caused the failure of the crankshaft. It was therefore anticipated that a similar failure would occur if a belt drive system were to be implemented in the E/28 drivetrain, as a more powerful motor than the one employed by the University of Victoria team was to be used. Given the multiple failures most likely attributed to the additional bending load created by the tension of a belt drive connection, combined with the increased design and analysis work to mount and connect the motor in a belt driven configuration, it was determined that an axially aligned motor position was beneficial. During the component selection phase of the EcoCAR 3 project, the team saw a potential for the electric motor to be directly coupled to the engine, and selected an electric motor and ICE capable of this speed ratio. The motor and ICE have similar top speeds, with the YASA P400 electric motor having a top speed of 8000 rpm [58] and the ICE having a top speed of 7000 rpm [60].

49 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Based on this decision, a mounting bracket was required to fasten the electric motor to the engine block along with a coupling shaft to allow torque transmission between the electric motor and crankshaft. Considering that one of the identified complications of this motor mounting method was the increase in overall powertrain length, any modifications which served to minimize the number of additional mounting brackets between components was preferred. The decision was made to connect the electric motor to the front of the engine rather than the rear for a number of reasons. One primary concern was regarding the availability of stock features required for mounting the clutch flywheel. The output side of the engine already contained a crankshaft flange designed to interface with a flywheel. Placing an electric motor here would require that this flywheel interface be replicated behind the motor to allow the manual clutch to be installed. Additionally, the downward slope of the vehicle hood meant that moving the engine even further forward would cause clearance issues at the top of the engine. Placing the motor at the front of the engine would allow the ICE to remain as far back as possible allowing the hood to close without additional changes. The limitation to minimize powertrain length lead to the decision to design and machine a modified front cover for the engine. This new cover retained all of the stock features which interfaced with the engine block while including a motor mounting profile along with the required shaft seals to allow the motor to be mounted as closely as possible to the engine. Due to limited support from the OEM for the selected ICE, the reverse engineering process began with generation of the 3D model of the existing front cover geometry. Figure 5.1 shows the Creaform Handyscan 3D scanner used to generate the initial

50 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

geometry of the stock component prior to modiﬁcation [61]. This handheld 3D scanner uses reﬂective markers placed on the component along with a projected laser grid and camera system to orient the relative position of the part and scanner in space. A point cloud model representing the part surface is then created by the accompanying scanning software which is then imported into Siemens NX 3D modelling software to produce a component matching the stock front cover.

Figure 5.1: Creaform HandySCAN 3D Scanner

From here, any additional features required to mount the electric motor were added to the generated model, with care taken to ensure that any features interfacing with components on the engine maintain their stock function. Images of the surface geometry generated by the 3D scanner as well as the final geometry of the modified component are shown in Figure 5.2. Due to the stock component being a cast aluminum part, certain features were simplified to facilitate the machining process intended for the newly designed part. In general, thin walled sections were replaced with thicker sections less likely to deform during machining, and exterior rounded corners were generally left square, or replaced with a chamfer. Once the modified geometry was completed, structural analysis within the Siemens NX environment was conducted to confirm that the new front

51 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 5.2: 3D Scan (left, center) & Final Modiﬁed Design (right) cover met the loading conditions outlined in section 5.1. The loading conditions and resulting peak stress values found using Siemens NX are shown in Table 5.2 and show that the front cover is more than capable of supporting the P1 motor while staying well below the yield stress of the selected material. Simulation results for the loading conditions can be seen in Appendix A.

Direction Longitudinal Lateral Vertical Load Case 20g 20g 8g Safety Factor 1.5 1.5 1.5 Load 8093 N 8093 N 3237 N Peak Stress (Sim) 59.08 MPa 40.10 MPa 7.904 MPa Supported Mass: 27.5 kg Yield Strength: 503 MPa

Table 5.2: P1 Motor Loading Conditions

The mounting interface for the electric motor was designed to the profile specified by the installation datasheet provided by the motor manufacturer. The motor bolting interface was also designed to mount the motor while maintaining the required concentricity and angular alignment of the motor and ICE crankshaft axes. The final

52 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 5.3: Final Installation of Front Cover w/ P1 Electric Motor installation of the front cover and P1 electric motor to the ICE is shown in Figure 5.3.

5.2.2 Crankshaft Coupling

With mounting of the electric motor completed, a shaft to connect the motor drive hub to the combustion engine crankshaft was required. The P1 electric motor position required an axial coupling solution to connect the female spline hub of the motor to the crankshaft front snout. The stock geometry of the front snout is designed to mate with the front crank pulley for auxiliary loads including the air conditioning compressor, alternator, and engine water pump, via a keyed shaft. Discussions with various organizers of the competition as well as technical engineers assigned to support the project brought to light the possibility that the design of the front snout would not support the potential full output load of the P1 electric motor. This limitation was taken into account when designing both the mechanical coupler as well as during the control system design. Based on the crankshaft failures experienced by the University of Victoria vehicle

53 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

design team, it was decided that a simple keyway shaft coupling would result in component failure as the two projects share the same motor-engine coupling challenge. Instead, an internal spline was cut into the end of the crankshaft to accept a coupler shaft whose opposite end contains a male spline matching the electric motor drive hub profile. The crankshaft modification as well as the additional coupler shaft can be seen in Figure 5.4. This spline coupling was designed in coordination with Rapid Precision Machining & Gearing Ltd., who were contracted in the final engineering of the spline details as well as the machining of the shafts.

Figure 5.4: Modiﬁed Crankshaft (left) & P1 Motor Coupler (right)

Crankshaft material information provided by GM was used to determine that a de-rated motor peak torque would allow the selected spline proﬁle to support the required loads. This motor de-rating value fell in line with the maximum torque ﬁll required to reach the transmission torque limit as well as the expected maximum generator power rating under various driving conditions. CarTech® Aermet® 100 Alloy was selected as the material for the coupling shaft due to its hardness, strength, and ductility, making it an ideal material for shaft components. A number of applications for Aermet® 100 include aerospace and military

54 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

use in landing gear, armor, fasteners, actuators, jet engine shafts, and drive shafts [62]. Additional considerations in the P1 coupler design were made with regards to thermal conditions applied to the electric motor drive hub. The P1 coupler shaft design effectively extends the engine crankshaft into the hub of the motor. It was ultimately decided that the temperature of the coupling shaft would not pose any significant issue for the motor. The crankshaft was expected to maintain the same temperature as the engine oil due to its distance from the combustion chamber as well as the volume of oil flowing over and past the crankshaft to reach the oil pan outlet ports. Engine oil operating temperatures are expected to remain within the range of 90°C and 105°C. The final expected temperature of the coupling at the motor hub location is lower than the internal crankshaft temperature, and falls within the operating range of temperatures for the motor rotor and stator, illustrated in Figure 5.5.

Figure 5.5: YASA P400 Temperature De-Rating Curves

55 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

The ﬁnal details for this coupling shaft include a retention mechanism for the shaft, which was achieved via the existing internal thread of the crankshaft snout. A through hole was designed in the coupling shaft and an extended M10 bolt was used to secure the coupling shaft against axial movement from the crankshaft. The external dimensions for the coupling shaft were also designed to interface with a shaft seal pressed into the custom front cover where the crankshaft protrudes. The use of a shaft seal was also implemented on the original front cover interface with the stock crank pulley.

Figure 5.6: Modiﬁed Crankshaft with P1 Motor Coupler

The complete modiﬁed crankshaft can been seen in Figure 5.6 with the P1 motor coupler extension installed.

5.2.3 Coupling Failure & Proposed Modiﬁcations

Even given the considerations made to the coupling mechanism following discussions with the University of Victoria, the shaft designed for the P1 motor experienced a failure during testing of the assembled P1 motor and combustion engine. Removal of the failed shaft showed that the failure occurred on the smaller diameter end of the

56 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

shaft, at the point where the spline major diameter meets the solid shaft.

Figure 5.7: Failure of P1 Motor Coupler

The “starburst” fracture pattern of the shaft, shown in Figure 5.7, is indicative of a reversed torsional fatigue failure [63]. Considering that the coupling was only loaded in a single direction and for a short period of time, this fracture pattern suggests failure due to torsional vibration. Torsional vibration is a likely cause of the failure given that combustion engines inherently produce high torsional vibration due to the periodic nature of the piston ﬁring. The design of this shaft was also not optimal as no relief was included in the shaft design to minimize the stress concentration at the tool lead-out of the spline teeth. Considerations for a new shaft should include the addition of a relief cut at the end of the spline teeth cut to a diameter smaller than that of the spline minor diameter. This relief should have a smooth transition to the remainder of the shaft to more evenly distribute stresses during operation. Further analysis into the state of the material stock regarding hardness should be conducted to determine what eﬀect, if any, machining had to the material properties. This should also include an analysis as to what type of further hardening process

57 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

would help improve the performance of the shaft, including investigation into both through and case hardening of the shaft. Case hardening of this component could be achieved through a nitriding process, a common hardening process used for gearing. If no acceptable solutions can be found to include a removable coupling shaft of this nature, another option to help improve the eﬀectiveness of this motor coupling would be to have a custom crankshaft made, a common practice for competition race vehicles. A new crankshaft could include all the stock geometry of the original crank while including an integrated spline to interface with the electric motor. This solution, although the most costly, would yield the strongest motor and ICE combination as the reduced diameter shaft would be removed from the system.

5.3 Combustion Engine Modiﬁcations

A number of modifications to the stock combustion engine were required to facilitate both the addition of electric motors to the powertrain as well as to allow the extended powertrain length of fit within the limited engine bay space of the vehicle chassis. Packaging issues were addressed through a number of changes including reverse engineered engine closures to prevent mounting and packaging interference as well as auxiliary system electrification. Aside from modifications to allow for proper component integration and packaging, certain engine subsystems were changed to produce additional power and achieve better fuel economy figures. These targets are primarily achieved by changing the combustion fuel type as well as the turbocharger parameters.

58 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

5.3.1 Auxiliary Component Electriﬁcation

The stock crankshaft pulley along with all belt driven auxiliary components must be moved to accommodate the P1 electric motor mounted directly to the front of the engine. Nearly all auxiliary functions driven by the accessory belt were either electrified and relocated to operate independently of the engine, or were made redundant and replaced by functionality provided by one of the electric motors. In addition to allowing the vehicle to operate with accessory functions available while the engine is off which may be required during various drive modes, accessory electrification also serves to remove a number of parasitic loads from the engine which can directly improve fuel economy and available power output.

Starter Motor & Alternator

The addition of the P1 electric motor directly mounted to the front of the crankshaft means that both the engine starter motor and alternator become redundant as the electric motor can be used to start the combustion engine as well as operate in generator mode to recover kinetic energy into the HESS, which can in turn charge the vehicle low voltage (LV) (12V) battery. Both stock components were removed to maximize available engine bay space. Any resulting mounting opening for these components were sealed with a cover plate to maintain environment sealing of the powertrain interior.

59 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Water Pump

The water pump which manages engine coolant ﬂow is another component generally driven by the accessory belt. In this case, a Davies Craig EWP 115 was used instead. This allowed coolant ﬂow to be controlled independent of engine speed and may in some cases improve engine operation as full pump speed control is available to the vehicle controller. The selected pump, shown in Figure 5.8, is capable of pumping 115L/min to replace the stock engine water pump.

Figure 5.8: Davies Craig EWP115 Electric Water Pump

Vacuum Pump

The LTG engine making up the combustion portion of the powertrain contained a camshaft mounted vacuum pump which, while not reliant on an accessory belt for operation, provided vacuum pressure which in turn operated the brake booster for power braking. Because brake power is required during all drive modes, even with the engine oﬀ, it was not possible to have the vacuum pump dependent on engine operation as certain drive modes operate with the engine oﬀ. In order to maintain brake power during driving conditions where the engine is

60 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

not running, an electrically driven vacuum pump was selected and mounted in the vehicle in cooperation of the design team, with the power pickup oﬀ of the camshaft simply capped to maintain sealing of the engine interior. This vacuum pump is driven oﬀ the LV electrical system and is connected to a vacuum reservoir which serves to maintain vacuum under repeated braking actuations.

A/C Compressor

The air conditioning compressor is another component which is generally driven directly by the engine accessory belt. Because the design goal of the vehicle was to retain as many functions as possible in order to maintain all aspects of consumer acceptability, all heating, ventilation, and air conditioning (HVAC) system functionality was maintained. With the loss of the accessory belt driving the stock A/C compressor, the team selected and integrated an electric A/C compressor into the vehicle. A

220-400 VDC compressor with integrated inverter used in the Azure Dynamics Electric Ford Transit as well as the factory Hybrid Ford Escape was selected. This compressor, manufactured by Mitsubishi, is able to support full A/C functionality and operates as part of the high voltage (HV) electrical system.

Power Steering Pump

Although power steering pumps are often driven oﬀ the accessory belt, the 2016 Camaro used as the vehicle platform for this project came equipped with an electric power steering pump making this potential modiﬁcation no longer required.

61 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

5.3.2 Front Cover

The engine front cover required replacement with a custom cover with an integrated electric motor mount. The cover was required to retain the original component’s ability to seal the timing chain compartment from the environment, as this area is lubricated by various oil jets. In addition to sealing against the remaining stock engine components, it must also contain the requisite electric motor mounting geometry as outlined in the motor installation guide. As a mounting point for the motor, the front cover was therefore required to be strong enough to support the motor under the test cases outlined in Table 5.1. Details of the front cover with integrated P1 motor mount are outlined in section 5.2.1.

5.3.3 E85 Fuel Conversion

The ICE selected for this project was modiﬁed by the design team using an E85 inline fuel sensor and engine map. This modiﬁcation was made to improve both the fuel sustainability and performance potential of the ICE under various conditions. Ethanol fuel blending has been increasingly approved for vehicle use by the U.S. EPA. The EPA began approving the use of E15 fuel, up to 15% ethanol blended with gasoline, in 2011 for vehicles of the 2001 model year and newer [64]. These regulatory changes towards fuel blending is a result of pushes to reduce oil dependence and GHG emissions through the use of ethanol as a renewable fuel produced from corn, sugar cane, and grasses [64]. Although ethanol, which can make up anywhere from 51% to 85% of E85 fuel

62 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

available at the pump, yields approximately 30% less energy than an equivalent volume of gasoline, the E85 fuel sensor monitors the current ethanol percentage and the modified fuel maps can adjust engine operating parameters to compensate for the difference. Benefits of the conversion to E85 fuel, aside from reducing the overall GHG emissions of the vehicle, include a significant increase in fuel octane rating when compared to regular pump gas, as well as improved air charge cooling properties. Both of these properties can serve to improve the combustion engine performance when desired. The improved octane rating of E85 fuel can significantly reduce detonation of fuel, especially given the turbocharged operation of the ICE. Furthermore, the increased heat of evaporation of E85 fuel helps to cool the air charge entering the combustion chamber to further increase potential power output [65]. These characteristics work well with a performance-oriented forced-induction engine to produce improved power and torque output while maintaining stable combustion and minimizing detonation.

5.3.4 Turbocharger Upgrade

To further raise the performance limit of the combustion engine, the Vermont Tuning turbocharger upgrade was selected to replace the stock turbocharger on the ICE. The turbocharger on the stock LTG engine is an LD04 unit manufactured by Mitsubishi. The stock unit contains a cast 19T compressor wheel and relatively small L sized turbine wheel [66]. A smaller turbine helps to limit turbo lag, the delay between throttle application and boost pressure generation, as less turbine mass requires less time to accelerate to operating speed. The turbo upgrade kit from Vermont Tuning replaces the cast 19T compressor

63 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

with a proprietary machined 67mm diameter compressor wheel to increase boost pressure capability. In order to drive the larger compressor, the turbine wheel is also upgraded from an L turbine to a larger 9 blade HL wheel [66]. The larger turbine can support higher power production from the turbocharger unit at the cost of increased turbo lag required to accelerate the larger wheel. This lag is less of an issue for an electriﬁed powertrain as the electric motor, with peak torque production at low speed, can supply the requested torque as the turbocharger spools.

5.3.5 Dry Sump Oil Pan

The added clutch pack and P2 electric motor between the ICE and transmission caused the transmission to move towards the rear of the vehicle while the engine moved towards the front. Although adequate clearance in the transmission tunnel posed no issues regarding the transmission repositioning, the engine relocation posed some packaging challenges. The new forward engine position caused the stock wet sump oil pan to interfere with the front subframe and steering rack of the vehicle. If the engine were to be raised to clear these systems, the engine would sit higher in the engine bay causing collisions with the hood, as well as raising the center of gravity of the vehicle, which would negatively impact vehicle dynamics and handling characteristics. In order to overcome the oil pan collision issue, a low-proﬁle oil pan was designed to allow the engine to remain in the same vertical position while resting above the subframe and steering rack. The new oil pan also converted the engine oil system from wet sump to dry. This served a secondary purpose of improving the robustness of the engine oil system under aggressive dynamic driving situations. The new dry

64 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

sump oil pan with minimal depth is shown in Figure 5.9. The additional clearance gained by the shortened pan can be seen when compared to the bottom of the front cover and electric motor, which reach a low point similar to that of the stock oil pan.

Figure 5.9: Dry Sump Oil Pan

A conventional wet sump oil system has a large oil pan at the bottom of the engine where oil collects and is drawn up from an intake submerged in the standing oil. This system, while adequate for regular driving conditions, poses some problems for performance driving situations. One such problem is an issue of oil starvation within the engine. With a conventional oil pickup point located in a shallow pan of oil, any prolonged lateral or longitudinal acceleration, often seen during wide, long corners at high speeds, or aggressive braking or acceleration, will cause the majority of the engine oil in the pan to be forced against the side of the oil pan, away from the oil pickup point. As these prolonged acceleration events are common during performance driving cycles and tracks, this causes the engine to go unlubricated for extended periods of time.

65 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Another issue present in a wet sump system is an issue of “windage”. This is essentially the drag caused by the lobes of the crankshaft being repeatedly forced through the oil in the pan, causing power losses due to the restriction to engine rota- tion, as well as a potential to aerate the oil, causing further issues with oil pumping. These issues are more pronounced during high-RPM operation, an uncommon engine speed range during typical driving conditions, but a frequent range for performance driving. Both of these issues are solved with a dry sump system, as a shallow pan at the base of the engine serves only to collect the oil towards pickup points where it is pulled into an external oil reservoir. This reservoir contains an air-oil separator to ensure that any oil ﬂowing to the reservoir outlet contains no air mixed in during the pumping process, as well as allowing for a stable oil source for the engine. With no oil standing at the base of the engine, the crankshaft is free to rotate in air, reducing drag and minimizing power losses. Many dry sump pumps can in fact produce enough suction signiﬁcantly reduce the air pressure within the crankcase to further reduce crankshaft drag as it is not rotating through a partial vacuum. In general, a dry sump oil system solves both the issues of packaging an extended powertrain as well as increasing the vehicle drivability during performance driving cycles.

5.3.6 Belt Driven Oil Pump

A dry sump oil system required that the stock oil pump, internal to the oil pan, be removed and replaced with an external oil pump. For this application, a Moroso 3-stage external oil pump was used. Because the oil pump was required to operate

66 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

only when the engine was running, a belt drive system was designed to couple the crankshaft to the oil pump input shaft. This ensured that the oil pump was driven as a function of the engine speed, a common driving method for these pumps. A mounting plate was designed to hold the oil pump to the engine block, with a lightweight pump sprocket designed by the team to produce the speed ratio suggested by Moroso. The prototype pump sprocket manufactured using an Orion 3D printer for testing purposes can be seen in Figure 5.10 in purple. With the geometry testing and alignment conﬁrmed, the component was contracted to Rapid Precision Machining & Gearing Ltd..

Figure 5.10: Oil Sprocket Prototype (left), Oil Pump Belt (right)

The stock oil pump was chain driven from the crankshaft by a combination timing chain and oil pump sprocket. This design was replicated in the belt-driven external oil pump through the reverse engineering of the combination drive sprocket in concert with Rapid Precision Machining & Gearing Ltd. to produce a sprocket with the stock timing geometry combined with the belt proﬁle required by the pump drive. The oil

67 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

pump belt connection along with a closeup of the combination timing and oil pump sprocket can be seen in Figure 5.10.

5.4 Clutch

In order to change between series and parallel drive modes, a 2-plate manual clutch pack was added between the ICE and P2 electric motor. Rather than a conventional driver operated clutch release bearing, the clutch master cylinder was driven by an electric actuator controlled directly by the vehicle control system. The selected Tilton Engineering, Inc. clutch pack can support the full powertrain torque to ensure that clutch slippage does not occur during performance driving cycles and high-torque request situations.

5.4.1 Flywheel

As ICE starter functionality had been taken over by the P1 electric motor, the engine flywheel no longer required the larger outer ring gear for interfacing with the stock starter motor. This allowed the flywheel to be redesigned to interface with the aftermarket 2-plate clutch pack selected for the powertrain, as well as to minimize rotational inertia. In the stock configuration, the flywheel for the manual clutch variant of the LTG engine served both as the friction surface for the clutch coupling, acting as the primary mechanical coupling interface, as well as the connection point for the starter motor, which normally drives a toothed ring at the periphery of the flywheel. With the starter motor interface no longer required, the flywheel was required only to provide a friction

68 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

surface for the clutch pack to couple the crankshaft to the adjacent component.

Figure 5.11: Custom Flywheel (left) & 2-Plate Clutch (right)

Working with Tilton Engineering, Inc. engineers, a flywheel was designed to act as the friction surface for the 2 plate racing clutch designed to switch operating modes for the powertrain, while matching the crankshaft bolt pattern. The modified clutch design can be seen in Figure 5.11 along with the installed clutch pack. Cooperation with Tilton Engineering, Inc. during the design process ensured that any design requirements for effective operation of the clutch pack were maintained and verified. The flywheel designed in cooperation with Tilton Engineering, Inc. matches as closely as possible to the flywheels available directly from them for operation with the clutch pack, with modifications made only to fit the LTG engine selected for the powertrain.

5.4.2 Housing

The clutch housing is one of two structural members required to extend the powertrain to accommodate the addition of components between the engine and transmission. The clutch pack and P2 electric motor are each enclosed within a housing designed to support the components of their respective systems while also bridging the gap

69 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

formed by separating the transmission bell housing from the transmission ﬂange of the engine.

Direction Clutch Actuation Static Installation Load Case 2491 N 1.5g Safety Factor 1.5 1.5 Load 3737 N 6456 N Peak Stress (Sim) 93.43 MPa 44.68 MPa Supported Mass: 292.5 kg Yield Strength: 503 MPa

Table 5.3: Clutch Housing Loading Conditions

The housing directly connected to the engine served to fully enclose the button flywheel and dual-plate clutch pack ensuring that no intrusion of dust, debris, or liquid from the vehicle exterior compromises the friction characteristics of the clutch pack. It also supported a hydraulic release bearing used to engage and disengage the clutch in order to change drive modes. The rear wall of the housing was designed to support the full actuation and holding force of the release bearing when the clutch is disengaged. The release bearing with hydraulic lines passing through the housing wall is shown in Figure 5.12 as well as a view of the clutch housing and clutch in position for test fitting, before installation on the engine. Locating pins between the engine and clutch housing ensure that alignment is maintained between all rotating components. Due to a number of factors affecting the final design and manufacturing method for the housing, a single large billet was used as the raw material for the components. One reason for choosing a billet machined component was to maintain accuracy of all locating pin and bolt hole locations. With locating pins between adjacent housings being the sole means of registration between a number of rotating components, a

70 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 5.12: Clutch Release Bearing (left) & Clutch Installed in Housing (right) welded housing was determined to have a high risk of deflection and deformation during and after the welding process. Another reason welding was not selected as a method of manufacture is due to material selection. Aluminum and steel alloys were both considered as a material for this housing. Steel, although tougher and stronger than aluminum, would have resulted in a housing weighing significantly more while being more difficult and time consuming to machine. With aluminum selected as the material of choice, an option of alloys presented itself. The main considerations for the selection were overall strength and toughness properties, along with manufacturability. 6061-T6 and 7075- T6 aluminum alloys were considered as the two main options for the component. 7075-T6 was the preferred material in this case due to the its significant increase in fatigue and yield strength over 6061-T6. As a main structural member of the powertrain, the housing is expected to operate under a number of conditions where vibrations are present and the improvement in fatigue strength is beneficial for the longevity of the powertrain. With a material selected, it was determined that a billet component would be

71 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the best manufacturing method due to the limited weldability of 7075-T6 aluminum. Concerns arose with the ability to effectively simulate and validate a welded design. A single machined component meant that an analysis of heat affected zones and other heat effects due to the welding process would not need to be simulated and assessed, to minimize the sources of potential error. The results of the simulation for the housing design are outlined in Table 5.4 and Table 5.3, and shown in more detail in Appendix A.

5.4.3 Actuation System

The use of an automatic transmission in this powertrain means that the manual clutch pack was not necessary for shifting. Rather than having an operator controlled clutch release bearing as in a conventional manual transmission, an electric actuator was used to allow the vehicle control system to use the clutch for the primary purpose of switching drive modes. An electric actuator capable of supplying the required linear force to the clutch master cylinder was controlled directly by the control system to allow the powertrain to switch from parallel to series hybrid operation. Table 5.4 shows the parameters used during the selection process for the clutch actuation components. The required actuation force and distance of the clutch release spring were used along with the eﬀective hydraulic area of the release bearing in order to determine the required line pressure in the clutch hydraulic system. This requirement was then used to select an appropriate master cylinder, taking into consideration the resulting input force and stroke distance. These parameters were then used in the selection of the ﬁnal actuator, whose stroke and force values are shown in

72 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Release Bearing Eﬀective Hydraulic Area 1.215 in2 Clutch Actuation Distance 0.308 in Clutch Actuation Force 560 lbf Minimum Line Pressure 461 psi Displaced Fluid Volume 0.374 in3

Master Cylinder Eﬀective Hydraulic Area 0.442 in2 Max Stroke 1.1 in

Actuation Requirement Stroke Distance 0.847 in Required Force 204 lbf

Linear Actuator Max Stroke 3 in Output Force 400 lbf

Table 5.4: Clutch Actuation Parameters

Table 5.4 to satisfy the requirements.

5.5 Primary Traction Motor (P2 Electric Motor)

During a variety of drive modes, the P2 electric motor, located between the clutch and automatic transmission, is the primary traction motor in the powertrain. The P2 motor is permanently coupled to the input shaft of the transmission, meaning that it is always rotating while the vehicle is driven. A lockup clutch within the torque convertor of the 8L90 transmission can be com- manded to close by the vehicle controller provided that a number of conditions set within the ﬁrmware of the transmission control module are met. One such condition is that the vehicle speed be above 13km/h. When engaged, the lockup clutch mechanically couples the input and output sides of the ﬂuid coupling in the torque converter allowing torque transmission in both directions. This clutch allows the P2 motor to

73 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

perform regenerative braking capabilities to improve overall vehicle energy efficiency. The 13km/h speed requirement may not have significant effect on the regenerative capability of the vehicle as braking is completely performed by friction brakes at low vehicle speeds due to limitations of the motor at low speed [67]. Regenerative braking capability for this powertrain will be limited, however, due to its RWD configuration. Front brakes typically produce the majority of the braking power due to a number of factors including front-biased static loading, with engine and transmission components generally housed in the front of the vehicle, as well as due to forward load transfer during vehicle deceleration. These factors can cause front brakes to perform up to 90% of the total braking force [68]. This means that energy recovery will be limited to a small fraction of the total recoverable braking force without the addition of a regenerative braking unit connected to the front wheels of the vehicle.

5.5.1 Housing

The housing for the P2 electric motor is the second structural housing designed to support the extended powertrain. In line with the production method for the clutch housing, the P2 motor housing was also designed as a single machined component from a block of 7075-T6 aluminum. The same analysis and manufacturing considerations were made for the two relatively similar housing components. Unlike the clutch housing, completed sealing of the interior of the housing from dust and liquid ingress was not required as the YASA P400-HC motor contains IP67 rated electrical components and IP55 rated mechanical components. This meant that all electrical components were already protected from all dust ingress and liquid

74 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

immersion to a depth of 1m while the mechanical components are, to a limited extent, protected from dust ingress as well as from low power water jets, conditions which are sufficient for wet driving. The design of the P2 motor housing was therefore mainly to act as a structural connection between the clutch housing and transmission bell housing, as well as a support structure for the motor itself. One design requirement for the motor housing was to sufficiently support the mass of the transmission, engine, and P1 electric motor during powertrain installation in the vehicle. This loading condition meant that the housing must support the load of all powertrain components in a vertical orientation when loaded between the front and rear flanges. Table 5.5 shows this loading condition and the resulting simulated peak stress within the housing. Further results for the simulation are shown in Appendix A.

Static Installation Load Case 1.5g Safety Factor 1.5 Load 6456 N Peak Stress (Sim) 44.32 MPa Supported Mass: 292.5 kg Yield Strength: 503 MPa

Table 5.5: P2 Motor Static Loading Requirement

With ingress protection a secondary concern, priority was given to eﬀective access to all motor connection points including electrical connections, liquid and air cooling ports, and instrumentation and sensor data lines. With all connection requirements accessible, protection from impacts and liquid intrusion from the environment was added where feasible, to add a secondary level of protection. The housing also served to align the drive axis between adjacent components. Alignment to the clutch housing and to the transmission bell housing was achieved

75 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

through locating pins present at each pair of mating flanges. Alignment of the motor to the housing was achieved both through spring pins located at the motor bolting holes, as well as a motor profile machined into the housing to provide further stability in motor mounting and alignment. As with the mounting for the P1 electric motor, the P2 housing and mount was designed to withstand the same loading conditions as prescribed in the competition loading requirements. In order to maintain minimal powertrain length, as well as to minimize size and weight, the P2 motor housing was designed such that the motor body itself added structural strength to the powertrain. With the motor installed in the housing, it was no longer a hollow housing bridging the gap between the clutch and transmission, but a rather more solid component, with the motor body nearly filling the entire space within the housing shown in Figure 5.13.

Figure 5.13: Completed P2 Motor Housing Rear (left) & Front(right)

The ﬁnal loading consideration for the P2 motor housing was to support the axial thrust load produced by the torque converter under certain loading conditions. The thrust value was determined through conﬁdential communications with GM engineers.

76 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

This load will be transmitted to the motor housing through a ﬂange on the motor drive shaft discussed in the next section. With shaft speeds ranging from 500 to 7000 rpm, a thrust needle-roller bearing was selected along with hardened steel thrust washers to support the load at the housing and shaft. The rear wall of the P2 motor housing was designed to support the full thrust load of the torque converter. The NX simulation results for the expected stress and displacement of the rear motor housing wall due to the torque converter thrust load can be seen in Figure 5.13. The peak stress values obtained from the NX simulation are shown in Table 5.6 for all three speciﬁed load cases along with the torque converter thrust load. The simulation results for each of the load cases can be seen in more detail in Appendix A.

Direction Longitudinal Lateral Vertical Load Case 20g 20g 8g Safety Factor 1.5 1.5 1.5 Load 8093 N 8093 N 3237 N Peak Stress (Sim) 39.67 MPa 10.62 MPa 4.747 MPa Supported Mass: 27.5 kg Yield Strength: 503 MPa

Table 5.6: P2 Motor Loading Conditions

5.5.2 Motor Drive Shaft

A shaft used to connect the motor spline drive to the ﬂex plate on the torque convertor was designed to permanently couple the two components. As with the P1 motor coupler, the motor drive shaft is manufactured from CarTech® Aermet® 100. This drive shaft is the sole carrier for all load input to the torque convertor. As the only input shaft to the transmission, this component was designed to carry the

77 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

full torque produced by the powertrain. The P2 motor shaft was designed to interface with both the clutch plates and YASA motor hub allowing the shaft to be driven by the P2 electric motor as well as by the engine.

Figure 5.14: Motor Drive Shaft Stress (left) & Topological Optimization (right)

The shaft geometry was imported into solidThinking Inspire to complete both structural loading analysis as well as topological optimization. The torque converter mounting flange was fixed and the expected peak powertrain torque applied to the length of shaft coupled to the motor and clutch. The stress in the shaft was calculated along with a topological analysis to determine an optimal internal diameter. The shaft was ultimately left solid to minimize unnecessary manufacturing costs and improve the safety factor of the shaft. The analyses results can be seen in Figure 5.14 Shaft geometry was determined primarily based on the dimensions required to interface with the spline hub of the YASA motor and the bolt pattern of the transmission flex plate. To corroborate the topological optimization of the shaft produced by solidThinking Inspire, manual shaft stress calculations were carried out to determine the maximum inner diameter allowable to carry the full load required by the

78 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

shaft.

T r τ = (5.1) zx J

π(r4 − r4) J = o i (5.2) 2

With no expected signiﬁcant loading of the P2 shaft in bending or tension, only torsional stress was addressed in the following calculations. Equation 5.1 was used to determine the torsional stress, τzx, of the shaft at a point a radial distance r from the center of the shaft, for a given applied torque, T [69]. The equation also sees a relationship with the polar moment of inertia, J, of the given shaft. The polar moment of inertia of a hollow cylinder is shown in Equation 5.2, where ro and ri represent the respective outer and inner radii of the shaft [69].

0 2 2 1/2 σ = (σx + 3τzx) (5.3)

The resulting Von Mises stress, σ0, caused by the 1000Nm torque expected to be carried by the coupling shaft was then found using Equation 5.3 [69]. Given that no bending or tensile loading is considered in this calculation, the normal stress, σx, can be omitted from this equation. The resulting equation was used to determine the expected peak stress due to the maximum torque load of the powertrain, along with the maximum allowable inner diameter of the shaft if the decision were made to machine a hollow shaft. The outer diameter of the shaft used in the calculation was determined as the root diameter of the required spline, while two diﬀerent shaft inner diameters were investigated.

79 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Constraints T 1000 Nm ro 16.5 mm

Case 1

ri 12.5 mm τzx 0.211 GPa J 78 078 mm4 σ0 0.366 GPa SF 4.70

Case 2

ri 15.5 mm τzx 0.641 GPa J 25 761 mm4 σ0 1.11 GPa SF 1.55 Yield Strength: 1.72 GPa

Table 5.7: P2 Shaft Stress Calculations

The results of the stress calculations are outlined in Table 5.7. The two cases selected for the analysis included a conservative inner diameter of 25mm representing the dimension suggested as a result of the topological optimization performed in solidThinking Inspire. The second case was selected to determine the maximum allowable inner diameter of the shaft while maintaining the 1.5 safety factor desired in the component. It was found that a 31mm inner diameter would still support the peak torque of the powertrain with a safety factor of 1.55 if bending and tension forces are not present. In addition to transmitting the full powertrain load, the motor drive shaft ﬂange was designed both to bolt the shaft to the ﬂex plate of the torque converter, as well as transfer the axial thrust load produced by the torque converter to the P2 motor housing. This was accomplished via a thrust needle-roller bearing designed to allow the thrust to be carried by the P2 housing even while the motor drive shaft rotates up to peak engine and motor speeds of 7000rpm. The recess to receive the needle-roller

80 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 5.15: Completed Motor Drive Shaft bearing can been seen on the right end of the completed motor drive shaft shown in Figure 5.15.

5.6 Transmission & Driveline

One speciﬁc requirement regarding the selection of a transmission for this vehicle was that it must not be driver controlled. A manual transmission was allowed provided that it be actuated by a vehicle control strategy rather than the driver directly. In this case, an automatic transmission was selected to simplify the control system as well as integration complexity. The selected transmission was available in particular trim levels of the vehicle chassis. This simpliﬁed the communication between the transmission and vehicle control system as stock wiring harnesses as well as an OEM transmission control module could be used to communicate with the transmission itself. The GM 8L90 transmission selected for the powertrain is the variant of the 8- speed automatic transmission supporting the highest torque capacity. This allows the combined combustion and electric powertrain to make use of its entire torque

81 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

output. As an automatic transmission used in multiple vehicles, two different torque con- verters interfacing with the transmission were available. Of the two, one exhibited less slip for a given torque transfer across the converter, meaning that the converter was more efficient but would result in less torque multiplication. This particular torque converter was selected for this powertrain as the cumula- tive torque output of the ICE and electric motors was more than sufficient for all applications. The benefits of the marginal efficiency improvement of the converter can provide benefits in efficiency energy usage without concern for lack of torque.

5.6.1 Prop Shaft

The stock vehicle provided as a chassis platform for the project contained a powertrain capable of producing 250kW and 385Nm. With power output increasing by nearly a factor of 2 and torque output by 2.5, to 447kW and 1000Nm, a driveshaft capable of supporting greater torque ﬁgures was required. In order to accomplish this, the two piece stock driveshaft was replaced with a 3 inch diameter, one-piece driveshaft in cooperation with SPi Performance Tuning.

5.6.2 Diﬀerential & Half Shafts

The final portion of the stock driveline which required modification was the replacement of the stock open differential and half shafts with components from the more powerful SS trim level of the Camaro. The new limited slip differential (LSD) provided a more favourable gear ratio given the power and torque characteristics of the modified powertrain. The differential and new half shafts were also capable of higher

82 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

torque limits given the increased output of the electriﬁed powertrain. The LSD also improved performance during aggressive driving conditions.

83 Chapter 6

Proposed Testing Plan

This chapter discusses the proposed testing phases including which testing apparatus are to be used as well as what functionality is to be tested during each phase. This test plan will be a detailed high-level overview of the testing schedule and will not discuss the detailed test cases developed by the controls system group within the vehicle design team. The testing procedures will be investigated; beginning with component-level testing of all powertrain components, both stock and modiﬁed, and increase in component scope until a full powertrain test is reached. The electric and combustion portions of the powertrain will be tested independently before a combined powertrain test. Baseline data from components will be compared against published data where applicable to verify testing procedures. The facility at McMaster University’s Automotive Resource Center contains three major dynamometer systems with which the powertrain and its components will be tested. The three units proposed for this testing plan include the AVL DynoSpirit e-motor test cell, the Horiba Automotive Test Systems engine test cell, and a driveline

84 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

test cell from A&D Technology.

6.1 Electric Motor Testing (AVL Motor Dyno)

With the P1 electric motor acting as both the engine starter motor and as a generator during series operation, and the P2 electric motor as the primary drive motor connected directly to the transmission input, electric motor testing is the ﬁrst of the component tests conducted for the powertrain. Both of the YASA P400-HC electric motors will be tested on an AVL DynoSpirit system for e-motor testing shown in Figure 6.1.

Figure 6.1: AVL DynoSpirit for e-Motor Testing

This system is capable of conducting steady-state speed and torque testing as well as simulations of road load and gradient. It also allows motors to be run through various driving cycles to test motor driveability [70]. This dyno will allow the controls system group to ensure that the PM150DZR

85 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

motor controllers produced by Rinehart Motion Systems are calibrated to the specific operating parameters to its particular electric motor. Once functionality of the motors can be verified, the dyno will allow the motors to be tested under load to ensure that the controls system developed by the vehicle design team performs as expected. With the electric motor mounted to the AVL test cell, both the ultracapacitor pack and combined HESS can also be tested when directly powering the electric motors. This testing will allow the HESS design team to validate controls systems for the HESS as well as determine whether sufficient thermal management systems are in place for the modules within each portion of the pack. The HESS used to power the E/28 powertrain is the result of joint research between Tyler Stiene and the McMaster Engineering EcoCAR 3 team. Additional information regarding the HESS can be found in Stiene’s thesis: “Analysis of a Hybrid Energy Storage System and Electrified Turbocharger in a Performance Vehicle” [71]. The test cell will also allow the electric motors to be tested in generating mode to provide specific performance data to be used by the controls system team while the vehicles operates in series mode as well as during regenerative braking scenarios. Finally, running the motors on the test cell using the HESS as a power source will allow the controls system team to generate data regarding the actual performance of the motors during different HESS states of charge.

6.2 Combustion Engine Testing (Horiba Dyno)

Having completed the baseline testing of the electric motor, and conﬁrming that the controls system is communicating with the motors and motor controllers properly,

86 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the combustion engine is the next powertrain component to be tested. The engine testing will be conducted on an engine test cell manufactured by Horiba Automotive Test Systems shown in Figure 6.2.

Figure 6.2: Horiba Engine Test System

With modifications made to the engine in the form of both aftermarket conversion kits as well as custom designed engine components, initial startup and idling stability may require significant test bench time. Although certain modifications affect the physical layout of the engine such as repositioning of the oil pump, oil filter relocation, and oil pan modifications, the essential operation of the engine remains stock. The cam timing remains driven by a timing sprocket on the crankshaft, reverse engineered to maintain the original timing and chain profile. The oil pump similarly remains driven by the sprocket but now by belt rather than chain. The engine oil loop has been modified slightly to a dry sump system. While the intended functionality should not pose major issues to engine operation, the test bench will help verify that

87 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

the modified oil system maintains the pressures and flow rates required by the engine, as well as whether engine timing has been affected by the new timing sprocket.

6.2.1 Engine Start and Idling

Considering that the majority of the engine system has undergone only cosmetic or limited functional modifications, the startup and idle stability test is simply to ensure that the engine functions as expected, as the engine was not run prior to modifications. With the modified engine mounted to an engine support stand connected to the Horiba Dyno test cell, the engine crankshaft is connected to the input of the Horiba Dyno. All supporting auxiliary systems required to sustain engine operation are connected to the engine via support arms on the same engine stand. These auxiliary systems include the engine coolant loop and radiator, the oil filter and cooler, as well as an air charge cooler required for the turbocharged intake. The P1 motor will not be connected to the engine for the initial starting and idling test. The Horiba Dyno cell motor will instead be used to drive the crankshaft in order to start the engine. With full control of the Horiba motor, the ability of the engine to be started and maintain idle can be tested independent of the P1 motor functionality. This initial testing phase is simply to determine whether the modified engine is capable of operating properly given the modifications made. Once any potential issues are addressed, further testing of the electrified portion of the powertrain can be tested.

88 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

6.2.2 Integrated Starter/Generator

The first electrified component which is to be tested is the ability of the P1 electric motor to be used as both a starter motor for the engine as well as a generator when the vehicle operates in series hybrid mode. A number of tests are to be conducted to verify the effectiveness of the selected P1 motor coupling mechanism as well as to ensure proper functionality of the vehicle controls system. The first test will be simply to determine that the modified coupling shaft designed to connect the electric motor drive hub to the engine crankshaft will not pose any further problems to the system. One of the main concerns for this coupling shaft is whether its direct connection to the engine crankshaft will cause any thermal issues to the electric motor. In order to determine this, the P1 motor will not be connected to the front cover of the engine, with the coupling shaft simply protruding from the front of the engine. Colour-changing temperature indicating stickers for a range of temperatures will then be applied to the end of the shaft. With the combustion engine again started by the Horiba Dyno motor, it will be run through a range of operating speeds and loads. The shaft will then be monitored by both a laser guided infrared thermometer as well as a thermal imaging camera. This test will determine the expected temperature rise of the coupling shaft as it is directly connected to the crankshaft, and will help determine if damage to the P1 electric motor can be expected due to excess temperature. This monitored test will determine whether the assumption made during the design phase that the crankshaft, and therefore P1 coupler, will reach a steady state

89 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

temperature near that of the engine oil at approximately 95°C. Once the temperature of the motor coupling during continuous operation is determined, the P1 motor can then be attached to the engine and will be safely assumed to operate with no risk of thermal overload due to the coupling shaft proximity to the engine. The startup logic of the controls system can then be applied to the P1 motor and combustion engine combination to ensure that the electric motor can effectively start the engine combustion cycle. This testing phase will allow the controls system team to determine if any changes to motor operating parameters are necessary to facilitate effective engine startup. An important detail includes the ability for the motor to switch to freewheel operation immediately following effective engine combustion in order to minimize potential issues with the electric motor and engine both producing torque when not desired. During this phase, secondary testing can be conducted to help preserve the extended operating health of the engine. The conversion to a dry sump oil system with additional lengths of piping for oil travel may cause the engine to begin the combustion cycle with insufficient lubrication. This is not an expected issue as the engine control module (ECM) should not fire spark plugs until sufficient oil pressure is reached. Various sensors in the oil system can help determine if fuel injection and spark ignition must be delayed for a number of engine crank cycles to allow proper oil pressure to develop and sufficient engine journal lubrication to be established. A range of operating speeds can also be tested to determine if the modified oil system provides sufficient oil pressure, and therefore engine lubrication, under a number

90 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

of operating conditions.

6.2.3 Baseline Operation

A number of standardized driving cycles will be run with limited engine modifications to verify that the engine performs as expected. Driving cycles ranging from standard highway, city, and combined cycles, along with performance driving cycles, can be performed to better understand baseline operation of the specific engine used for the vehicle. This test will again allow the controls system team to verify that the engine is operating as expected given the modified communications to the stock vehicle controller. The team will also be able to compare data from the vehicle controller to determine whether the signals match, or vary as expected, from data recorded during operation of a stock vehicle with no modifications.

6.2.4 Turbocharger Upgrade

Up to this point, the majority of modifications to the engine were simply to satisfy physical packaging demands, such as a lower profile oil pan. The switch to a dry sump oil system was made to improve dynamic driving performance. While these modifications have affects on engine operation, the majority of them function with the engine running under normal operating conditions; that is, operating parameters including fuel flow and ignition timing are not significantly affected. Having tested baseline engine operation using the modified oil system, changes to engine subsystems which affect combustion parameters and behaviours can now be incrementally made and tested.

91 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

The first of these changes is the upgraded turbocharger. This turbocharger upgrade supplied by Vermont Tuning consists of a unit with larger turbine and compressor wheels to increase air charge generated by exhaust gasses and come with a number of modified ECM maps to facilitate the new engine parameters. The swap to a larger turbocharger can now be made with the engine on the test cell and the same driving cycles can be assessed. Data from the new operating behaviours will then be logged and any desired modifications to the Vermont Tuning engine tunes can be made. This new operating data can be used to fine-tune the controls system, which was designed and written with no actual test data, but solely based on the engine tune supplied by Vermont Tuning.

6.2.5 E85 Fuel Maps

The second major modification which will affect the operating parameters of the engine was the conversion to allow the engine to burn an E85 fuel blend (gasoline blended with up to 85% ethanol). This modification was made simply with the addition of an inline ethanol fuel sensor added to the fuel sending line between the fuel tanks and engine. In addition to an ethanol sensor, a number of fuel lines were changed from the stock materials to those capable of withstanding the effects of a higher ethanol concentration. In particular, certain aluminum alloys and seal materials may be negatively affected by ethanol over time. The fuel maps required for the engine to operate on this new fuel mixture were also provided by Vermont Tuning as a part of their E85 fuel upgrade kit. These maps

92 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

can again be veriﬁed by running a number of driving cycles with the combustion engine on the test cell to validate their eﬀectiveness.

6.2.6 Conﬁrm Modiﬁed Engine Parameters

At this point, the combustion engine has been incrementally tested with progressive additions of modified systems, both custom designed, and available as kits from manufacturers. All modifications have been added to the engine and any potential issues have been assessed in the process. The controls system team is now free to test a range of combustion driving cycles, or the combustion portion of hybrid driving cycles, to determine if the engine is behaving as expected. Data from the dyno test cell will be logged and assessed to determine if modifications to the controls system logic is required, or if any lookup tables for various operating modes require updating. A completed engine build also allows the team to log actual performance data points to inform the controls system logic regarding torque limits of various components in a number of drive modes, as well as determining if any mechanical connections throughout the powertrain are insufficient to carry the required loads.

6.3 3-Axis Driveline Testing (A & D Driveline Dyno)

The ﬁnal test setup designed to test powertrain sub-systems prior to full powertrain testing is the 3 input driveline test cell. The facility at McMaster University contains a dyno test cell from A&D Technology capable of providing power to 3 locations of a driveline. One input/output unit is shown in Figure 6.3.

93 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure 6.3: Single A&D Dyno Unit

Having tested the engine and electric motors independently on both the AVL and Horiba dyno test cells, the drivetrain rearward of the engine can be tested on the 3- axis dyno. This test cell will operate with the clutch and clutch housing, P2 electric motor, transmission, prop shaft, RDU, and half shafts, mounted to a t-slot table set into the test cell floor. The rear portion of the driveline will be supported by removing the rear subframe from the vehicle and mounting it directly to the t-slot tables. This allows the existing subframe to act as a mounting system for the RDU, half shaft, and rear uprights. This simplifies the setup as only the transmission and extended bell housings must be supported, along with the effective height of the wheel hubs, given that the rear suspension will remain on the vehicle.

94 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

6.3.1 Clutch Testing

The manual clutch pack is the forward component in the driveline test cell, and is the first component to undergo testing on this cell. With an adapter designed to allow the button flywheel to be mounted to the input drive of the dyno unit, the clutch operation can be tested under a number of operating conditions. The linear actuator selected for this application was available in limited stroke lengths. In order to fully actuate the release bearing for the clutch, the master cylinder and release bearing combination requires a specific stroke distance to ensure complete actuation with no overtravel under various wear conditions of the clutch plates. To achieve the required stroke distance, the selected linear actuator was disassem- bled and modified, with the shaft shortened and the travel limit switches relocated. This modified actuator can now be tested on the dyno test cell to ensure that the required stroke is produced, as well as determining the resulting actuation time for the clutch system. Without an assembled test stand with the clutch pack installed, the clutch engagement and disengagement duration is based only on actuator speed figures published by the manufacturer as well as unloaded speed testing of the actuator. The rated static and dynamic load of the actuator can then be confirmed with a fully connected hydraulic clutch release system. Completion of actuator testing will be followed with testing the ability of the clutch actuation system to engage and disengage the drive shaft from the engine flywheel. As this testing phase is designed to run in parallel with, or following the completion of engine dyno cell testing, engine parameters logged from the test cell can be used to realistically replicate the flywheel output dynamics of the clutch system.

95 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

6.3.2 Speed Matching Logic

A fully operational clutch actuation system will allow the controls system team to evaluate the eﬀectiveness of the speed matching logic of the vehicle controller. When switching between series and parallel drive modes, the clutch is required to couple the ﬂywheel, driven by the engine, with the P2 motor drive shaft, driven by the electric motor. As both components coupled by the clutch pack are powered, speed matching logic is required to bring the ICE and motor speeds together, minimizing any potential component damage due to additional torque transmitted during the clutch engagement process..

6.3.3 Transmission Shifting

One of the final components which is controlled by the vehicle controls system is the transmission. The 8-speed automatic transmission has been outfitted with a stock transmission control module (TCM) reflashed by GM specifically to support this vehicle build, allowing for more direct control of the requested gear position. The driveline test cell will allow a number of torque and shift request tests to be conducted, with the input unit replicating engine output and the mounted P2 electric motor producing torque as well. A number of test scenarios laid out by the controls system team can be conducted, ranging from economy drive cycle shift maps to performance driving shift points. This transmission shifting test phase can provide feedback as to whether the selected shift points are adequate or require modification, as well as to verify the transmission behaviour under various conditions.

96 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

6.3.4 Regenerative Braking

One final test which will be conducted on the driveline dyno test cell is the behaviour of the transmission during a regenerative braking request. The transmission used in the vehicle is a conventional automatic transmission which uses a fluid coupling torque convertor to allow the vehicle to stop while the engine continues to rotate. Generally, a torque converter is directional in its transmission of torque, meaning that while the coupling will transmit power when driven by the input side of the unit, providing power to the output side of the converter may cause unexpected behaviours. While this does not pose a major issue in a combustion based powertrain, the ability to implement regenerative braking in a HEV requires that the fluid coupling be able to transmit torque in both directions. The 8L90 transmission selected for the powertrain has a feature which can be used to allow this behaviour. In order to improve driveline efficiency, the transmission contains a torque converter lockup clutch which, when engaged, directly couples the input and output shafts of the torque converter. Additional control over this lockup clutch is one feature enabled by the custom TCM reflash provided to support this project. This clutch can therefore be engaged during a regenerative braking request to allow the P2 electric motor to be driven in generator mode when braking is required. Although control over the clutch is enabled by the modified TCM firmware, there are still questions regarding the limitations of the lockup clutch. It is possible that the original limitation remains of a minimum rpm under which the clutch will auto- matically disengage. Testing on the driveline dyno will allow issues such as these to be tested to determine if modifications to regen braking logic must be revised in the vehicle controller.

97 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

6.4 Combined Driving Cycle Testing

Up to this point in the testing plan, the focus of the testing phases has been to progressively increase the complexity and scope of the powertrain subsystem testing beginning with individual component level testing of parts such as electric motors, clutch actuators, and the combustion engine. With each test cell containing a portion of the powertrain, each subsystem within the powertrain is tested on one or more of the dyno cells. At this point, the powertrain has not been tested as a whole, but rather each section has been tested using data logged from one or more of the other test cells as a virtual connections between the components. With satisfactory results from the separate test cells, the powertrain can be fully reassembled and installed in the vehicle chassis for the ﬁnal testing phase. This test portion will allow the powertrain to be tested with components directly coupled, rather than the number of virtual connections created by using data logged from one test cell as inputs for another. In order to run this phase of the test plan, the vehicle should be mounted to a chassis dyno to allow the vehicle wheels to operate as if it were being physically driven. The selected chassis dyno should be capable of supporting vehicles with power outputs equal to the theoretical maximum of the designed powertrain. A rolling chassis dyno at the McMaster Automotive Resource Center is a potential testing unit for the assembled vehicle, provided the power output of the powertrain can be supported by the unit. If the required power levels cannot be tested on the particular chassis dyno, outside dyno test centers can be selected for this process. SPi Performance Tuning who has supported various aspects of the driveline redesign, is a potential

98 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

candidate for this testing, as their experience with testing and tuning high-powered vehicles suggests that their chassis dyno is capable of supported the power output of the powertrain. A number of driving cycles selected for this testing phase will be run on the chassis dyno and the actual power and torque values produced at the wheels can be recorded. In addition to power and torque ﬁgures, a chassis dyno capable of measuring emissions will also allow the team to verify the theoretical emissions produced by the powertrain. These number can then be compared to the torque and power ﬁgures, as well as the combined fuel economy and emissions values generated by the vehicle model created by the system modeling and simulation team to select the powertrain components and test controls strategies.

6.4.1 Investigating Power-Split Logic

A fully assembled powertrain tested in the vehicle chassis will facilitate further investigation of power-split logic options to test which strategies will result in the desired performance. A physically assembled powertrain will allow the controls system team to develop alternative power-split logic to determine if the selected vehicle control logic is optimal for either power or eﬃciency, as required. The in-chassis testing will also allow for a comparison to the control logic which has been tested on the previous dyno test cells to determine if there were factors which were overlooked in the virtual connections between powertrain subsystems. Issues regarding both the translation of data from one test cell output to the input of another can be evaluated, along with any potential driveline eﬃciency losses, whether electrical or mechanical.

99 Chapter 7

Conclusion

The global automotive market has begun to see a significant push to reduce fuel consumption through regulatory changes to limit manufacturer fleet-wide average fuel economy figures. This target has been addressed by manufacturers through a number of changes including the design of vehicles using alternative fuel sources such as ethanol fuel blends, as well as the implementation of electrified powertrain technologies. Historically, electrified vehicles have been limited to utility based vehicles with limited performance characteristics which are simply focused on improved everyday fuel economy. The introduction of high performance electrified vehicles in the automotive market suggests that hybrid powertrains are capable of powering more than just fuel efficient vehicles. The recent resurgence of the American muscle car market is a prime target for the development of performance-oriented electrified powertrains while still fulfilling the ever increasing fuel economy requirements. Through the development of a performance based PHEV as a competitor in Eco- CAR 3, the most recent AVTC, McMaster University has shown that it is possible to

100 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

develop an electrified powertrain capable of competing with current PHEV offerings by major automotive manufacturers while also providing the performance characteristics of top-level American muscle cars. A series-parallel hybrid configuration with electric motors in the P1 and P2 position provides adequate power for daily driving and achieves excellent fuel economy, while providing ample performance when desired on a racetrack. The inclusion of a HESS provides electrical energy capacity desired for reasonable all-electric range while also providing the extreme power levels desired for aggressive driving situations. The design and implementation process outlined in this thesis has resulted in a hybrid electric powertrain capable of meeting both upcoming fuel economy regulations as well as the performance expectations of American muscle car buyers. Future research on the topic of performance oriented hybrid electric vehicles includes the execution of a testing plan similar to that which is laid out in this thesis. Individual components can be tested to define their performance characteristics and assess their viability in a relatively unconventional powertrain, followed by system level testing to determine control strategies to optimize both fuel economy and power output as required, along with effective power management.

101 Appendix A

Powertrain Mount Simulation Results

Figure A.1: Front Cover Longitudinal Loading - Constraints

102 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.2: Front Cover Longitudinal Loading - Simulated Displacement

Figure A.3: Front Cover Longitudinal Loading - Simulated Von Mises Stress

103 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.4: Front Cover Lateral Loading - Constraints

Figure A.5: Front Cover Lateral Loading - Simulated Displacement

104 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.6: Front Cover Lateral Loading - Simulated Von Mises Stress

Figure A.7: Front Cover Vertical Loading - Constraints

105 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.8: Front Cover Vertical Loading - Simulated Displacement

Figure A.9: Front Cover Vertical Loading - Simulated Von Mises Stress

106 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.10: Clutch Housing Actuation Force - Constraints

Figure A.11: Clutch Housing Actuation Force - Simulated Displacement

107 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.12: Clutch Housing Actuation Force - Simulated Von Mises Stress

Figure A.13: Clutch Housing Actuation Force - Simulated Von Mises Stress (alternate view)

108 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.14: Clutch Housing Static Installation Loading - Constraints

Figure A.15: Clutch Housing Static Installation Loading - Simulated Displacement

109 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.16: Clutch Housing Static Installation Loading - Simulated Von Mises Stress

Figure A.17: P2 Motor Housing Longitudinal Loading - Constraints

110 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.18: P2 Motor Housing Longitudinal Loading - Simulated Displacement

Figure A.19: P2 Motor Housing Longitudinal Loading - Simulated Von Mises Stress

111 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.20: P2 Motor Housing Lateral Loading - Constraints

Figure A.21: P2 Motor Housing Lateral Loading - Simulated Displacement

112 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.22: P2 Motor Housing Lateral Loading - Simulated Von Mises Stress

Figure A.23: P2 Motor Housing Vertical Loading - Constraints

113 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.24: P2 Motor Housing Vertical Loading - Simulated Displacement

Figure A.25: P2 Motor Housing Vertical Loading - Simulated Von Mises Stress

114 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.26: P2 Motor Housing Torque Converter Loading - Constraints

Figure A.27: P2 Motor Housing Torque Converter Loading - Simulated Displacement

115 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

Figure A.28: P2 Motor Housing Torque Converter Loading - Simulated Von Mises Stress

116 References

[1] Ali Emadi, Mehrdad Ehsani, and John M. Miller. Vehicular Electric Power Systems: Land, Sea, Air, and Space Vehicles. CRC Press, 2003.

[2] Berker Bilgin, Pierre Magne, Pawel Malysz, Yinye Yang, Vera Pantelic, Matthias Preindl, Alexandre Korobkine, Weishend Jiang, Mark Lawford, and Ali Emadi. Making the case for electriﬁed transportation. IEEE Transactions on Trans- portation Electriﬁcation, 1(1):4–17, 2015.

[3] Office of the Press Secretary. Obama Administration Finalizes His- toric 54.5 MPG Fuel Efficiency Standards, August 2012. URL https://obamawhitehouse.archives.gov/the-press-office/2012/08/28/ obama-administration-finalizes-historic-545-mpg-fuel-efficiency-standard. Accessed 20 April 2017.

[4] Marmon Holdings, Inc. The Marmon Wasp, n.d. URL http://www.marmon. com/the marmon wasp.html. Accessed 1 January 2017.

[5] Jaguar Heritage. 1950s - Grave, Space and Pace, n.d. URL http://www. jaguarheritage.com/t/history 1950. Accessed 1 January 2017.

117 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[6] World Endurance Championship. Classes, n.d. URL http://www.ﬁawec.com/ presentation/classes.html. Accessed 1 January 2017.

[7] TOYOTA Motorsport GmbH. TOYOTA GAZOO Racing HANDBOOK, Jan- uary 2016. URL https://www.racingbytmg.com/en/wec/wec-ts050-hybrid/. Ac- cessed 2 April 2017.

[8] Porsche. Technical Specs 919 Hybrid, n.d. URL http://www.porsche.com/ canada/en/eventsandracing/motorsport/worksracing/racingcars/919-hybrid/ featuresandspecs/. Accessed 2 April 2017.

[9] Audi. Audi in the 2016 WED, July 2016. URL https://www.audi-mediacenter. com/en/audi-in-the-wec-2016-5806. Accessed 2 April 2017.

[10] Steven De Groote. F1 rules and stats 2000-2009, January 2009. URL http: //www.f1technical.net/features/27. Accessed 3 January 2017.

[11] F´ed´erationInternationale de l’Automobile. 2014 FORMULA ONE TECHNICAL REGULATIONS, July 2011. Accessed 3 January 2017.

[12] Mercedes. Mercedes’ Andy Cowell on more power, more noise and more races, February 2016. URL https://www.formula1.com/en/latest/interviews/2016/ 2/mercedes -andy-cowell-on-more-power--more-noise-and-more-races.html. Ac- cessed 3 January 2017.

[13] F´ed´erationInternationale de l’Automobile. 2016-2017 FIA Formula E Champi- onship Technical Regulations, September 2016. Accessed 3 January 2017.

[14] Tom Ford, Charlie Turner, and Ollie Marriage. LaFerrari vs McLaren P1

118 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

vs Porsche 918, November 2014. URL https://www.topgear.com/car-news/ supercar/laferrari-vs-mclaren-p1-vs-porsche-918. Accessed 16 March 2017.

[15] Máté Petrány. This Is How The Techno Fabulous McLaren P1 Makes 903 Horsepower, February 2013. URL http://jalopnik.com/ this-is-how-the-techno-fabulous-mclaren-p1-makes-903-hy-294642750. Accessed 20 March 2017.

[16] Tom Burkart. 2014 McLaren P1, June 2016. URL http://www.topspeed.com/ cars/mclaren/2014-mclaren-p1-ar153561.html. Accessed 20 March 2017.

[17] Porsche. Introducing the Porsche 918 Spyder, May 2013. URL http://press. porsche.com/news/release.php?id=787. Accessed 21 March 2017.

[18] Steve Dent. Tesla’s latest 100D models focus on range, not power, January 2017. URL https://www.engadget.com/2017/01/20/ teslas-latest-100d-models-focus-on-range-not-power/. Accessed 25 March 2017.

[19] The Tesla Team. New Tesla Model S Now the Quickest Production Car in the World, August 2016. URL https://www.tesla.com/en CA/blog/ new-tesla-model-s-now-quickest-production-car-world. Accessed 22 March 2017.

[20] Frank Markus, Brian Brantley, and Cory Lutz. 2017 Tesla Model S P100D First Test: A New Record - 0-60 MPH in 2.28 Seconds!, February 2017. URL http://www.motortrend.com/cars/tesla/model-s/2017/ 2017-tesla-model-s-p100d-ﬁrst-test-review/. Accessed 22 March 2017.

119 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[21] Bob Sorokanich. The Tesla Model S P100D Is Not the ”Fastest Car in the World”, August 2016. URL http://www.roadandtrack.com/new-cars/news/ a30536/tesla-model-s-p100d-quickest-not-fastest/. Accessed 22 March 2017.

[22] Rimac Automobili. Concept One The Supercar of The Future, Today, n.d. URL http://www.rimac-automobili.com/en/supercars/concept one/. Accessed 25 March 2017.

[23] Jens Meiners. 2016 Audi R8 e-tron: The Electriﬁed R8 Finally Arrives, March 2015. URL http://www.caranddriver.com/news/ 2016-audi-r8-e-tron-photos-and-info-news. Accessed 25 March 2017.

[24] Mark Kane. Audi R8 e-tron In Detail, 2015. URL http://insideevs.com/ audi-r8-e-tron-detail/. Accessed 25 March 2017.

[25] Natural Resources Canada. Most fuel-eﬃcient vehicles, February 2017. URL http://www.nrcan.gc.ca/energy/eﬃciency/transportation/cars-light-trucks/ buying/7479. Accessed 1 February 2017.

[26] U.S. Environmental Protection Agency. Search by EPA Size Class, n.d. URL https://www.fueleconomy.gov/feg/byclass/2016ClassList.shtml. Accessed 1 February 2017.

[27] U.S. Environment Protention Agency. Frequently Asked Questions, n.d. URL http://www.fueleconomy.gov/feg/info.shtml. Accessed 8 February 2017.

[28] Merriam-Webster.com. muscle car, n.d. URL https://www.merriam-webster. com/dictionary/muscle%20car. Accessed 21 December 2016.

120 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[29] MuscleCarClub.com. Muscle Car Deﬁnition, n.d. URL http://www. musclecarclub.com/muscle-car-deﬁnition/. Accessed 1 February 2017.

[30] Robert Benz. Muscle Cars Explained: History, Evolution & Buyer’s Guide, July 2013. URL https://www.gentlemansgazette.com/ muscle-cars-explained-history/. Accessed 8 February 2017.

[31] Racing-Reference.info. 1949 NASCAR Strictly Stock Results, n.d.. URL http: //racing-reference.info/raceyear/1949/W. Accessed 8 February 2017.

[32] Racing-Reference.info. 1950 NASCAR Grand National standings for 1950, n.d.. URL http://www.racing-reference.info/yeardet/1950/W. Accessed 8 February 2017.

[33] PBS History Detectives Special Investigations. Drag Racing, n.d. URL http:// www.pbs.org/opb/historydetectives/feature/drag-racing/. Accessed 13 February 2017.

[34] James B. Treece. 10 ways the 1073 oil embargo changed the industry, October 2013. URL http://www.autonews.com/article/20131014/GLOBAL/ 131019959/10-ways-the-1973-oil-embargo-changed-the-industry. Accessed 13 February 2017.

[35] Environmental and Energy Study Institute. Fact Sheet: A Brief History of Octane in Gasoline: From Lead to Ethanol, March 2016. URL http://www. eesi.org/papers/view/fact-sheet-a-brief-history-of-octane. Accessed 13 February 2017.

121 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[36] Sangho Choo and Patricia L. Mokhtarian. The Relationship of Vehicle type Choice to Personality, Lifestyle, Attitudinal, and Demographic Variables. Re- search Report UCD-ITS-R-02-06, Institute of Transportation Studies, University of California, Davis, 2002.

[37] Sashank Musti and Kara M. Kockelman. Evolution of the household vehicle ﬂeet: Anticipating ﬂeet composition, PHEV adoption, and GHG emissions in Austion, Texas. Transportation Research Part A, 45(8):707–848, October 2011.

[38] Edmunds.com. Ford Mustang History, n.d.. URL https://www.edmunds.com/ ford/mustang/history/. Accessed 28 March 2017.

[39] Ford Motor Company. 2017 mustang speciﬁcations, n.d. URL http://www.ford. ca/cars/mustang/speciﬁcations/view-all/. Accessed 25 March 2017.

[40] Car and Driver. Ford Mustand Shelby GT350 / GT350R, n.d. URL http: //www.caranddriver.com/ford/mustang-shelby-gt350-gt350r. Accessed 18 April 2017.

[41] Edmunds.com. Chevrolet Camaro History, n.d.. URL https://www.edmunds. com/chevrolet/camaro/history/. Accessed 26 March 2017.

[42] Chevrolet. 2017 Camaro Models & Specs, n.d.. URL http://www.chevrolet.com/ camaro-sports-car/specs/trims.html. Accessed 26 March 2017.

[43] Chevrolet. 2017 Camaro ZL1 Models & Specs, n.d.. URL http://www.chevrolet. com/camaro-zl1/specs/trims.html. Accessed 26 March 2017.

[44] Edmunds. Dodge Challenger History, n.d. URL https://www.edmunds.com/ dodge/challenger/history/. Accessed 29 March 2017.

122 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[45] Motor Trend. Buyer’s Guide 2017 Dodge Challenger, n.d. URL http:// www.motortrend.com/cars/dodge/challenger/2017/#speciﬁcations. Accessed 28 March 2017.

[46] U.S. News & World Report. Dodge Challenger SXT Coupe Specs, n.d.. URL https://cars.usnews.com/cars-trucks/dodge/challenger/2017/specs/ challenger-sxt-coupe-385998. Accessed 30 March 2017.

[47] U.S. News & World Report. Dodge Challenger R/T Coupe Specs, n.d.. URL https://cars.usnews.com/cars-trucks/dodge/challenger/2017/specs/ challenger-rt-coupe-385997. Accessed 30 March 2017.

[48] U.S. News & World Report. Dodge Challenger SRT 392 Coupe Specs, n.d.. URL https://cars.usnews.com/cars-trucks/dodge/challenger/2017/specs/ challenger-srt-392-coupe-386001. Accessed 30 March 2017.

[49] U.S. News & World Report. Dodge Challenger SRT Hellcat Coupe Specs, n.d.. URL https://cars.usnews.com/cars-trucks/dodge/challenger/2017/specs/ challenger-srt-hellcat-coupe-386000. Accessed 30 March 2017.

[50] Dr. W. Hackmann. BU HEV Electrical Traction Drives: HEV E-Drive Develop- ment and Products, November 2012.

[51] Ali Emadi, Kaushik Rajeshekara, Sheldon S. Williamson, and Srdjan M. Lukic. Topological Overview of Hybrid Electric and Fuel Cell Vehicular Power System Architectures and Conﬁgurations. IEEE Transactions on Vehicular Technology, 54(3):763–770, May 2005.

123 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[52] Jinming Liu. Modelling, Conﬁguration and Control Optimization of Power-Split Hybrid Vehicles. Ph.d. dissertation, The University of Michigan, 2007.

[53] Ali Emadi, Young Joo Lee, and Kaushik Rajashekara. Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug-In Hybrid Electric Vehicles. IEEE Transactions on Industrial Electronics, 55(6):2237–2245, 2008.

[54] Yinya Yang, Kamran Arshad-Ali, Joel Roeleveld, and Ali Emadi. State-of-the- art electriﬁed powertrains - hybrid, plug-in, and electric vehicles. International Journal of Powertrains, 5(1):1–29, 2016.

[55] Joel Roeleveld. On the Electriﬁcation of the American Muscle Car: An Analysis and Model Based Design. Master’s thesis, McMaster University, August 2015.

[56] Thomas Grissom. Turbocharging for Improved Engine Performance & Reduced CO2 Emissions. SAE International, 2013.

[57] Vermont Tuning. Cadillac ATS 2.0T 390 HP E85 Package, n.d.. URL http:// www.vermonttuning.com/product/cadillac-ats-2-0t-390hp-package/. Accessed April 2016.

[58] YASA Motors. P400 Series Compact Axial Flux Motors And Generators, n.d.

[59] University of Victoria EcoCAR 2 Team. UVic Integration Issues - LE9 Engine and TM4 BAS+. Personal Communication, May 2015.

[60] General Motors. 2.0l turbo ltg the turbo with teeth, 2017. URL http://www. gmpowertrain.com/engines/2l-ltg.html. Accessed 13 July 2017.

124 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[61] creaform3d.com. handyscan-feature 5.png, n.d. URL https://www.creaform3d. com/sites/default/ﬁles/styles/image-feature-title/public/assets/metrology/ handyscan/handyscan-feature 5.png?itok=WBZ-TsSV. Accessed 15 April 2017.

[62] Service Steel Aerospace Corp. AerMet® 100 alloy data sheet, April 2016.

[63] Thomas Brown. Torsional Fatigue Failures: Identiﬁcation, Diagnosis and Pre- vention. Magazine, October 2014.

[64] www.fueleconomy.gov. Ethanol, n.d. URL https://www.fueleconomy.gov/feg/ ethanol.shtml. Accessed 16 April 2017.

[65] Andre Simon. Knowledge Boost: Ethanol Explained, April 2015. URL http:// www.speedhunters.com/2015/04/everything-you-need-to-know-about-ethanol/. Accessed 16 April 2017.

[66] Vermont Tuning. Camaro 2.0T 67mm Turbo Upgrade, n.d.. URL http://www. vermonttuning.com/product/ltg-20t-67mm-turbo-upgrade/. Accessed 13 April 2017.

[67] Porio Fajri, Venkata Anand K. Prabhala, Nima Lotﬁ, Mehdi Ferdowsi, and Pourya Shamsi. Emulating Electric Vehicle Regenerative and Friction Braking Eﬀect Using a Hardware-in-the-Loop (HIL) Motor/Dynamometer Test Bench. In Conference: Industrial Electronics Society, IECON 2014 - 40th Annual Con- ference of the IEEE. IEEE, 2014.

[68] James D. Halderman. Automotive Technology: Principles, Diagnosis, and Ser- vice. Prentice-Hall, fourth edition edition, 2012.

125 M.A.Sc. Thesis - Robert Lau McMaster - Mechanical Engineering

[69] Richard G. Budynas and J. Keith Nisbett. Shigley’s Mechanical Engineering Design. McGraw-Hill Education, tenth edition edition, 2015.

[70] AVL. AVL DynoSpirit, n.d. URL https://www.avl.com/ load-unit-for-e-motor-testing/-/asset publisher/gYjUpY19vEA8/content/ avl-dynospirit?uj=932542-931574&ujName=AVL%20DynoSpirit. Accessed 5 January 2017.

[71] Tyler Stiene. Analysis of a Hybrid Energy Storage System and Electriﬁed Tur- bocharger in a Performance Vehicle. Master’s thesis, McMaster University, Jan- uary 2017.

126