The Automotive Transmission Book (eBook)

Dr. Robert Fischer, AVL List GmbH, Graz, Austria Prof. Dr. Gunter Jürgens, Technical University Graz, Austria Prof. Dr. Ferit Küçükay, Technical University Braunschweig, Germany DI Rolf Najork, Heraeus Holding GmbH, Hanau, Germany Dr. Burkhard Pollak, pi3 GmbH, Weinheim Germany.

Preface 6
Table of Contents 8
Symbols, Indices and Abbreviations 15
Chapter 1 21
Core Task of Vehicle Transmissions 21
1.1 Traction Demand and Torque Supply at Constant Speed 22
1.1.1 Traction Demand at Constant Speed 22
1.1.2 Torque Supply at Constant Velocity 24
1.2 Traction Demand and Torque Supply for Transient Driving States 26
1.2.1 Traction Demand for Vehicle Acceleration 26
1.2.2 Torque Supply for Vehicle Acceleration 28
1.2.3 Fuel Economy Map of a Combustion Engine 28
1.2.4 Possibilities of Power Supply 29
1.2.5 Traction Force Diagram 30
1.2.6 Response Characteristics 31
1.2.7 Electric Motors for Hybrid and Electric Propulsion 33
1.3 Fuel Economy Optimization 35
1.3.1 Fuel Consumption Investigation 36
1.3.2 Shifting Operational Points 38
1.3.3 Optimization of the Internal Combustion Engine 41
1.3.4 Potential of Combined Shifting Operational Points and Optimization of the ICE 43
1.3.5 Efficiency 44
1.3.6 Trade-Off between Fuel Consumption and Driving Pleasure 47
1.4 Launch and Synchronizing Speeds 51
1.4.1 Clutches 52
1.4.2 Vehicle Launch 55
1.5 Gear Ratios and their Design 58
1.5.1 Gear Ratio 58
1.5.2 Requirements Imposed on Gear Ratio Design 59
1.5.3 Design Options for the Gear Ratio to Achieve Top Speed 61
1.5.4 Design of the Smallest Transmission Ratio as Overdrive 62
1.5.5 Design of the Largest Transmission Ratio 63
1.5.6 Design of the Number and Staging of the Gears 64
1.5.7 Trade-Offs in Gear Ratio Selection 67
1.5.8 Practical Design Comments 68
Chapter 2 69
Shift Dynamics and Shift Comfort 69
2.1 Fundamentals of Gear Ratio Change and Synchronization 69
2.1.1 Classification of Shift Sequences 69
2.1.2 Power Upshift as Powershift without Engine Torque Control 71
2.1.3 Power Upshift as Powershift with Engine Torque Control 74
2.1.4 Sensitivities for Power Upshifts as Powershifts 75
2.1.5 Power Downshift as Powershift 79
2.1.6 Power Upshift with Traction Force Interruption 80
2.1.7 Power Downshift with Traction Force Interruption 83
2.1.8 Operational Points During Shifts in the Engine Map 85
2.2 Power Train Dynamics 86
2.2.1 Power Train Model 88
2.2.2 Reduction of Inertia 91
2.2.3 Reduction of Spring Stiffness 92
2.2.4 Substitute System 93
2.2.5 Eigen Frequencies and Eigen Modes 95
2.2.6 Excitations 100
2.2.7 Forced Oscillation 103
2.2.8 Rotational Vibration Damping on the Transmission Input 105
2.3 Vehicle Acoustics 108
2.3.1 Transmission Caused Noise, Vibration, Harshness (NVH) 108
2.3.2 Transmission in Conjunction with the Acoustic Driving Impression 112
2.4 Vehicle Dynamics and Driver Interaction 114
2.4.1 Vehicle Dynamics 114
2.4.2 Dynamic Coupling 115
2.4.3 Influence of Shifting 116
2.4.4 Physiological Perceptions of the Human Being 117
Chapter 3 119
Power Transfer Elements 119
3.1 Fundamentals and Active Principles 119
3.1.1 Forms and Arrangements for Power Transfer 119
3.1.2 Shifting and Modulating the Power Transfer 122
3.1.3 Clutch Functionalities—Principles of Torque Transfer Through Friction 123
3.2 Simple Gear Stages 124
3.2.1 Design Criteria for Gear Stages 126
3.2.2 The Main Parameters of a Gear Set 127
3.2.3 Tooth Flank Modifications 128
3.2.4 Practical Design Guidelines for Spur Gear Pairs 130
3.2.5 Noise Optimization and Load Capacity Optimization of Meshing Gears 132
3.2.6 Bevel Gear Pairs 132
3.3 Planetary Gear Stages 134
3.3.1 Structure and Kinematics of the Simple Planetary Gear Stage 134
3.3.2 Graphical Determination of Transmission Ratios 136
3.3.3 Forces, Torques, Losses 140
3.3.4 Design Guidelines 140
3.3.5 Production 141
3.3.6 Complex Planetary Gear Sets 142
3.3.7 Power Split 143
3.3.8 Differentials 144
3.4 Sliding Gears and Dog Clutches 146
3.4.1 Active Principle and Areas of Implementation 146
3.4.2 Design Principles 147
3.4.3 Examples of Actual Designs 149
3.5 Dry Clutches 151
3.5.1 Design Characteristics of a Dry Clutch 153
3.6 Wet Clutches 155
3.6.1 Fundamentals of Torque Transfer with Mixed Friction 155
3.6.2 Heat Balance of Wet Clutches 156
3.6.3 Friction Lining Wear 159
3.6.4 Oil Load and Friction Lining Load 160
3.6.5 Drag Torque 161
3.7 Synchronizer Units 161
3.7.1 Abstraction and Motivation 161
3.7.2 Structure and Function of a Synchronizer Unit 162
3.7.3 Synchronization Systems 167
3.7.4 Design and Optimization Guidelines 167
3.8 Fluid-Dynamic Converter and Lock-Up Clutch 168
3.8.1 Function and Curves of Fluid-Dynamic Converters 168
3.8.2 Design Guidelines Torque Converters 172
3.8.3 Function and Principles of the Lock-Up Clutch 172
3.9 Continuously Variable Power Transfer 175
3.9.1 Active Principle 175
3.9.2 Push-Belt and Chain Variators 177
3.9.3 Traction Drive Variator, Friction Wheel Variator 180
3.9.4 Variator of the Cone Ring Transmission 181
3.9.5 Lubrication and Clamping 182
Chapter 4 183
Actuation, Servo, and Auxiliary Systems 183
4.1 Fundamentals and Active Principles 183
4.1.1 Reducing Force Requirements 185
4.2 Transfer Elements 187
4.2.1 Force Transfer from Stationary to Rotating Elements 187
4.2.2 Apply and Release Systems 188
4.2.3 Inner Shift System 188
4.3 Cooling and Lubrication 190
4.4 Requirements for Servo and Actuation Systems 191
4.5 Hydraulic Actuation 192
4.5.1 Pumps 192
4.5.2 Valves for Control and Regulation 197
4.5.3 Further Components 198
4.5.4 Control Subsystems 200
4.5.5 Electrohydraulic Actuation Systems 203
4.6 Pneumatic Actuation 204
4.6.1 Properties of Air as a Medium 204
4.6.2 Pneumatic Components 204
4.6.3 Example of Pneumatic Clutch Control 205
4.7 Electromechanical Actuation 206
4.7.1 Energy Converters 207
4.7.2 Power Transfer 210
4.7.3 Actuator Designs 211
4.8 Energy and Power Balance 214
Chapter 5 216
Controls 216
5.1 Electronic Control Units 216
5.1.1 Overview 216
5.1.2 Interfaces 218
5.1.3 Micro-controller 220
5.1.4 Monitoring Device 220
5.1.5 Current Control 220
5.1.6 Electro-magnetic Compatibility 220
5.1.7 Control Unit Designs 221
5.2 Software Architecture 222
5.2.1 Architecture 223
5.3 Signal Processing 225
5.3.1 Speed Sensors 225
5.3.2 Shift Fork Position Sensors 226
5.3.3 Pressure Sensors 226
5.3.4 Temperature Sensors 227
5.3.5 Shifter Position Sensors 227
5.3.6 Signal Processing and Filtering 227
5.3.7 Failure Detection 229
5.3.8 Onboard Diagnostics 230
5.3.9 Actuators 231
5.4 Selecting the Shift Point 232
5.4.1 Shift Strategy 232
5.5 Shift Execution 236
5.5.1 Controls 237
5.5.2 Adaptation 239
5.6 Safety in Transmission Systems 241
5.7 Calculating Torque Over Pressure 243
Chapter 6 247
Transmission Designs for Passenger Cars 247
6.1 Transmission Type Independent Attributes, Elements and Objectives 248
6.1.1 Power Train Arrangements 248
6.1.2 Transmission Development 249
6.1.3 Components in Transmission Design 252
6.1.4 Housing Development 257
6.1.5 Determination of Transmission Loads 259
6.1.6 Tolerance Analysis 261
6.1.7 Transmission Application and Calibration 261
6.2 Manual Transmissions 262
6.2.1 Layout and Subassemblies 263
6.2.2 Requirements for Manual Transmissions 264
6.2.3 Design of Manual Transmissions 265
6.2.4 Manual Transmission Examples 266
6.3 Automated Manual Transmissions 267
6.3.1 Layout and Sub-assemblies 268
6.3.2 Requirements for Automated Manual Transmissions 269
6.3.3 Design of Automated Manual Transmissions 270
6.3.4 Automated Manual Transmission Example 271
6.4 Dual Clutch Transmissions 273
6.4.1 Layout and Sub-assemblies 273
6.4.2 Requirements for Dual Clutch Transmissions 275
6.4.3 Design of Dual Clutch Transmissions 276
6.4.4 Dual Clutch Transmission Examples 277
6.5 Automatic Transmissions 280
6.5.1 Layout and Subassemblies of Automatic Transmissions 281
6.5.2 Requirements for Automatic Transmissions 282
6.5.3 Design of Automatic Transmissions 284
6.5.4 Automatic Transmission Examples 286
6.6 Continuously Variable Transmissions (CVTs) 287
6.6.1 Layout and Sub-assemblies of CVTs 288
6.6.2 Requirements for CVTs 290
6.6.3 Design of CVTs 290
6.6.4 CVT Example 290
Chapter 7 292
Power Train Electrification 292
7.1 Motivation and Objectives 293
7.1.1 Requirements for Electric and Hybrid Power Trains 294
7.2 Components and Configurations 296
7.2.1 Main Components for Electrification 296
7.2.2 Storage Systems for Electric Energy 299
7.2.3 Further Sub-Systems and Interaction with the Entire Vehicle 301
7.2.4 Series Hybrid 302
7.2.5 Parallel Hybrid 304
7.2.6 Power-Split Hybrid 305
7.2.7 Combinations of Hybrid Configurations 305
7.3 Functions and Strategies for Hybrid Power Trains 306
7.3.1 Start–Stop Function 306
7.3.2 Recuperation 307
7.3.3 Boost 307
7.3.4 Electric Driving 308
7.3.5 Shifting Operational Points 308
7.3.6 Operation Strategies 309
7.3.7 Degree of Electrification and Fuel Economy 311
7.4 Examples of Hybrid and Electric Power Trains 314
7.4.1 Micro Hybrids (Start-Stop Systems) 314
7.4.2 Power-Split Hybrids 315
7.4.3 Parallel Hybrid Examples 316
7.4.4 Combining Power-Split and Parallel Hybrid Architectures 317
7.4.5 Parallel Hybrid Based on DCT 318
7.4.6 Combining Parallel and Series Hybrid 320
7.4.7 Electric Propulsion Enhanced by Series and Parallel Hybrid 321
7.4.8 Transmissions for Electric Vehicles (EV) 323
7.4.9 Range Extender 323
Chapter 8 325
Transmission Applications Beyond the Passenger Car Sector 325
8.1 General Requirements Imposed on Transmissions Beyond the Passenger Vehicle Sector 325
8.2 Truck Transmission 329
8.2.1 Requirements Imposed on Commercial Truck Transmissions 330
8.2.2 Continuous Braking Devices 332
8.2.3 Design Guidelines for Commercial Truck Transmissions 334
8.2.4 Design Examples of Commercial Truck Transmissions 336
8.3 Bus Transmissions 340
8.3.1 Requirements Imposed on Bus Transmissions 340
8.3.2 Design Examples of Bus Transmissions 341
8.4 Tractor Transmissions 344
8.4.1 Requirements Imposed on Tractor Transmissions 345
8.4.2 Transmission as Part of the Chassis 346
8.4.3 Design Examples of Tractor Transmissions 347
8.5 Motorcycle Transmissions 350
8.5.1 Requirements Imposed on Motorcycle Transmissions 350
8.5.2 Design Examples with Foot Actuation 351
8.5.3 Examples of Automated Motorcycle Transmissions 353
8.6 Racing Transmissions 354
8.6.1 Racing Requirements 355
8.6.2 Materials Used in Formula 1 356
8.6.3 Design Example of a Formula 1 Transmission 356
Erratum to: The Automotive Transmission Book 359
References 360
Index 368