Provides technical details and developments for all automotive power transmission systems
The transmission system of an automotive vehicle is the key to the dynamic performance, drivability and comfort, and fuel economy. Modern advanced transmission systems are the combination of mechanical, electrical and electronic subsystems. The development of transmission products requires the synergy of multi-disciplinary expertise in mechanical engineering, electrical engineering, and electronic and software engineering.
Automotive Power Transmission Systems comprehensively covers various types of power transmission systems of ground vehicles, including conventional automobiles driven by internal combustion engines, and electric and hybrid vehicles. The book covers the technical aspects of design, analysis and control for manual transmissions, automatic transmission, CVTs, dual clutch transmissions, electric drives, and hybrid power systems. It not only presents the technical details of key transmission components, but also covers the system integration for dynamic analysis and control.
Key features:
- Covers conventional automobiles as well as electric and hybrid vehicles.
- Covers aspects of design, analysis and control.
- Includes the most recent developments in the field of automotive power transmission systems.
The book is essential reading for researchers and practitioners in automotive, mechanical and electrical engineering.
Table of Contents
Series Preface xi
Preface xiii
1 Automotive Engine Matching 1
1.1 Introduction 1
1.2 Output Characteristics of Internal Combustion Engines 2
1.2.1 Engine Output Power and Torque 2
1.2.2 Engine Fuel Map 4
1.2.3 Engine Emission Map 5
1.3 Road Load, Driving Force, and Acceleration 6
1.3.1 Axle Loads 7
1.3.2 Road Loads 8
1.3.3 Powertrain Kinematics and Traction 9
1.3.4 Driving Condition Diagram 13
1.3.5 Ideal Transmission 15
1.3.6 Power-Speed Chart 17
1.4 Selection of Gear Ratios 18
1.4.1 Highest Gear Ratio 18
1.4.2 First Gear Ratio 19
1.4.3 Intermediate Gear Ratios 20
1.4.4 Finalization of Gear Ratios 23
References 26
Problem 26
2 Manual Transmissions 29
2.1 Introduction 29
2.2 Powertrain Layout and Manual Transmission Structure 30
2.3 Power Flows and Gear Ratios 37
2.4 Manual Transmission Clutches 40
2.4.1 Clutch Structure 40
2.4.2 Clutch Torque Capacity 43
2.4.3 Clutch Design 44
2.5 Synchronizer and Synchronization 45
2.5.1 Shift without Synchronizer 45
2.5.2 Shift with Synchronizer 47
2.6 Dynamic Modeling of Synchronization Process 52
2.6.1 Equivalent Mass Moment of Inertia 53
2.6.2 Equation of Motion during Synchronization 55
2.6.3 Condition for Synchronization 56
2.7 Shifting Mechanisms 59
References 62
Problems 62
3 Transmission Gear Design 65
3.1 Introduction 65
3.2 Gear Design Fundamentals 66
3.2.1 Conjugate Motion and Definitions 66
3.2.2 Property of Involute Curves 67
3.2.3 Involute Curves as Gear Tooth Profiles 68
3.2.4 Characteristics of Involute Gearing 69
3.3 Design of Tooth Element Proportions of Standard Gears 72
3.3.1 Gear Dimensional and Geometrical Parameters 72
3.3.2 Standardization of Tooth Dimensions 72
3.3.3 Tooth Dimensions of Standard Gears 74
3.3.4 Contact Ratio 74
3.3.5 Tooth Thickness and Space along the Tooth Height 76
3.4 Design of Non-Standard Gears 78
3.4.1 Standard and Non-Standard Cutter Settings 78
3.4.2 Avoidance of Tooth Undercutting and Minimum Number of Teeth 79
3.4.3 Systems of Non-standard Gears 81
3.4.4 Design of Long-Short Addendum Gear System 82
3.4.5 Design of General Non-Standard Gear System 83
3.5 Involute Helical Gears 86
3.5.1 Characteristics of Involute Helical Gearing 87
3.5.2 Design Parameters on the Normal and Transverse Sections 87
3.5.3 Tooth Dimensions of Standard Involute Helical Gears 89
3.5.4 Minimum Number of Teeth for Involute Helical Gears 89
3.5.5 Contact Ratio of Involute Helical Gears 90
3.5.6 Design of Non-standard Involute Helical Gears 91
3.6 Gear Tooth Strength and Pitting Resistance 91
3.6.1 Determination of Gear Forces 91
3.6.2 AGMA Standard on Bending Strength and Pitting Resistance 93
3.6.3 Pitting Resistance 93
3.6.4 Bending Strength 94
3.7 Design of Automotive Transmission Gears 95
3.8 Planetary Gear Trains 103
3.8.1 Simple Planetary Gear Train 106
3.8.2 Dual-Planet Planetary Gear Train 107
3.8.3 Ravigneaux Planetary Gear Train 107
References 108
Problems 109
4 Torque Converters 111
4.1 Introduction 111
4.2 Torque Converter Structure and Functions 112
4.2.1 Torque Multiplication and Fluid Coupling 114
4.2.2 Torque Converter Locking up 115
4.3 ATF Circulation and Torque Formulation 116
4.3.1 Terminologies and Definitions 116
4.3.2 Velocity Diagrams 119
4.3.3 Angular Momentum of ATF Flow and Torque Formulation 122
4.4 Torque Capacity and Input-Output Characteristics 124
4.4.1 Torque Converter Capacity Factor 125
4.4.2 Input-Output Characteristics 127
4.4.3 Joint Operation of Torque Converter and Engine 128
4.4.4 Joint Operation of Torque Converter and Vehicle Powertrain 129
References 133
Problem 134
5 Automatic Transmissions: Design, Analysis, and Dynamics 137
5.1 Introduction 137
5.2 Structure of Automatic Transmissions 139
5.3 Ratio Analysis and Synthesis 153
5.3.1 Ford FWD Six-Speed AT 153
5.3.2 Ford six-speed RWD Ravigneaux AT 160
5.3.3 ZF RWD Eight-Speed AT 162
5.4 Transmission Dynamics 164
5.4.1 Ford FWD Six-Speed AT 165
5.4.2 Ford RWD Six-Speed AT 170
5.4.3 ZF RWD Eight-Speed AT 172
5.5 Qualitative Analysis on Transmission Shifting Dynamics 175
5.6 General Vehicle Powertrain Dynamics 186
5.6.1 General State Variable Equation in Matrix Form 187
5.6.2 Specific State Variable Equation 188
5.6.3 Solution of State Variables by Variable Substitution 192
5.6.4 Vehicle System Integration 193
5.7 Simulation of Vehicle Powertrain Dynamics 195
References 198
Problems 198
6 Automatic Transmissions: Control and Calibration 201
6.1 Introduction 201
6.2 Components and Hydraulic Circuits for Transmission Control 203
6.3 System Circuit Configurations for Transmission Control 216
6.3.1 System Hydraulic Circuitry for the Previous Generation of ATs 216
6.3.2 System Hydraulic Circuitry for ATs with Independent Clutch Pressure Control 218
6.3.3 System Hydraulic Circuitry for ATs with Direct Clutch Pressure Control 223
6.4 Transmission Control Strategy 225
6.4.1 Transmission shift schedule 225
6.4.2 Torque Converter Lock Control 228
6.4.3 Lock-Release Schedule 229
6.4.4 Lock-Release Operation 231
6.4.5 Engine Torque Control During Shifts 233
6.4.6 Shift Process Control 236
6.4.7 Initial Clutch Pressure Profiles 238
6.4.8 Initial Piston Stroke Attributes 239
6.4.9 Feedback Shift Control 239
6.4.10 Torque Based Shift Control 241
6.4.11 System Diagnosis and Failure Mode Management 245
6.5 Calibration of Transmission Control System 245
6.5.1 Component Level Calibration 246
6.5.2 System Level Calibration 247
References 249
Problem 250
7 Continuously Variable Transmissions 251
7.1 Introduction 251
7.2 CVT Layouts and Key Components 253 7.2.1 Belt Structure 254
7.2.2 Input and Output Pulleys 254
7.2.3 Basic Ratio Equation 255
7.3 Force Analysis for Belt CVT 257
7.3.1 Forces Acting on a Metal Block 257
7.3.2 Forces Acting on Pulley Sheaves 258
7.3.3 Block Compression and Ring Tension 262
7.3.4 Torque Transmitting Mechanism 263
7.3.5 Forces Acting on the Whole Belt 267
7.3.6 Relation between Thrusts on Input and Output Pulleys 268
7.3.7 Ratio Changing Mechanism 272
7.4 CVT Control System Design and Operation Control 273
7.4.1 VBS Based Control System 274
7.4.2 Servo Mechanism Control System 277
7.4.3 Comparison of the Two Control System Designs 285
7.5 CVT Control Strategy and Calibration 287
7.5.1 Line Pressure Control 287
7.5.2 Continuous Ratio Control Strategy 288
7.5.3 Stepped Ratio Control Strategy 292
7.5.4 CVT Control Calibration 293
References 295
Problems 296
8 Dual Clutch Transmissions 299
8.1 Introduction 299
8.2 DCT Layouts and Key Components 300
8.2.1 Dry Dual Clutch Transmissions 301
8.2.2 Wet Dual Clutch Transmissions 306
8.3 Modeling of DCT Vehicle Dynamics 307
8.3.1 Equations of Motion during Launch and Shifts 307
8.4 DCT Clutch Control 313
8.5 Clutch Torque Formulation 322
8.5.1 Correlation on Clutch Torque and Control Variable 322
8.5.2 Case Study on Clutch Torque and Control Variable Correlation 325
8.5.3 Algorithm for Clutch Torque Calculation under Real Time Conditions 327
8.5.4 Case Study for the Clutch Torque Algorithm 328
References 330
Problems 331
9 Electric Powertrains 333
9.1 Basics of Electric Vehicles 333
9.2 Current Status and Trends for EVs 333
9.3 Output Characteristic of Electric Machines 336
9.4 DC Machines 337
9.4.1 Principle of DC Machines 338
9.4.2 Excitation Types of DC Machines 342
9.4.3 Speed Control of DC Machines 343
9.5 Induction Machines 347
9.5.1 Principle of Induction Motors 348
9.5.2 Equivalent Circuit of Induction Motors 349
9.5.3 Speed Control of Induction Machine 352
9.5.4 Variable Frequency, Variable Voltage Control of Induction Motors 354
9.5.5 Efficiency and Losses of Induction Machine 355
9.5.6 Field-Oriented Control of Induction Machine 356
9.6 Permanent Magnet Motor Drives 361
9.6.1 Basic Configuration of PM Motors 361
9.6.2 Basic Principle and Operation of PM Motors 364
9.7 Switched Reluctance Motors 370
9.8 EV Transmissions 372
9.8.1 Single-Speed EV Transmission 372
9.8.2 Multiple Ratio EV Transmissions 374
9.9 Conclusions 379
Bibliography 380
10 Hybrid Powertrains 389
10.1 Series HEVs 390
10.2 Parallel HEVs 391
10.3 Series-Parallel HEVs 394
10.4 Complex HEVs 400
10.4.1 GM Two-Mode Hybrid Transmission 400
10.4.2 Dual Clutch Hybrid Transmissions 407
10.4.3 Hybrid Transmission Proposed by Zhang, et al. 413
10.4.4 Renault IVT Hybrid Transmission 415
10.4.5 Timken Two-Mode Hybrid Transmission 416
10.4.6 Tsai’s Hybrid Transmission 419
10.4.7 Hybrid Transmission with Both Speed and Torque Coupling Mechanism 421
10.4.8 Toyota Highlander and Lexus Hybrid, e-Four Wheel Drive 423
10.4.9 CAMRY Hybrid 424
10.4.10 Chevy Volt Powertrain 425
10.5 Non-Ideal Gears in the Planetary System 427
10.6 Dynamics of Planetary Gear Based Transmissions 427
10.7 Conclusions 428
References 429
Index 431
