Automotive Chassis Engineering

✍ Scribed by David C. Barton, John D. Fieldhouse

• Publisher: Springer
• Year: 2024
• Tongue: English
• Leaves: 377
• Edition: 2
• Category: Library

✦ Synopsis

Written for students and practising engineers working in automotive engineering, this book provides a fundamental yet comprehensive understanding of chassis systems and requires little prior knowledge on the part of the reader. It presents the material in a practical and realistic manner, using reverse engineering as a basis for examples to reinforce understanding of the topics. The specifications and characteristics of vehicles currently on the market are used to exemplify the theory’s application, and care is taken to connect the various topics covered, so as to clearly demonstrate their interrelationships. This second edition is fully updated and revised throughout and includes a new chapter on vehicle deceleration behaviour. The book opens with a chapter on basic vehicle mechanics, which includes the forces acting on a vehicle in motion, assuming a rigid body. The new chapter on vehicle deceleration behaviour introduces the basic concepts of a conventional foundation braking system before considering means of optimising the deceleration performance of any wheel-braked vehicle based on the tyre-road adhesion characteristics. The next chapter focuses on vehicle dynamics by considering suspension systems and how the important components of the system, the tyres, linkages, springs, dampers, etc., interact to give the required peformance characteristics for the vehicle. The book then proceeds to a chapter on steering systems, which provides readers with a firm understanding of the principles and forces involved under static and dynamic loading. The chapter on chassis structures and materials outlines analysis tools (typically, finite element analysis) and design features that are used to reduce mass and increase occupant safety in modern vehicles. The final chapter on noise, vibration and harshness (NVH) includes a basic overview of acoustic and vibration theory and makes use of extensive research investigations and practical experience asa means of addressing NVH issues. In all subject areas, the authors take into account the latest trends, anticipating the move towards electric vehicles, on-board diagnostic monitoring, active systems and performance optimisation. The book features a number of worked examples and case studies based on recent research projects. All students, including those on Master level degree courses in automotive engineering, and professionals in industry who want to gain a better understanding of vehicle chassis engineering, will benefit from this book.

✦ Table of Contents

Preface to the Second Edition
Preface to the First Edition
Contents
1 Vehicle Mechanics
1.1 Modelling Philosophy
1.2 Co-ordinate Systems
1.3 Tractive Force and Tractive Resistance
1.3.1 Tractive Force or Tractive Effort (TE)
1.3.2 Tractive Resistances (TR)
1.3.3 Effect of TR and TE on Vehicle Performance
1.4 Tyre Properties and Performance
1.4.1 Tyre Construction
1.4.2 Tyre Designation
1.4.3 The Friction Circle
1.4.4 Limiting Frictional Force Available
1.5 Rigid Body Load Transfer Effects for Straight Line Motion
1.5.1 Vehicle Stationary or Moving at Constant Velocity on Sloping Ground
1.5.2 Vehicle Accelerating/decelerating on Level Ground
1.5.3 Rear Wheel, Front Wheel and Four Wheel Drive Vehicles
1.5.4 Caravans and Trailers
1.6 Rigid Body Load Transfer Effects During Cornering
1.6.1 Steady State Cornering
1.6.2 Non-Steady State Cornering (Acceleration or Braking is Included)
1.7 Concluding Remarks
2 Deceleration Behaviour
2.1 Overview of the Brake System
2.1.1 Introduction
2.1.2 Functions and Requirements of a Brake System
2.2 Conventional Hydraulic Foundation Brake System
2.2.1 Brake System Components
2.2.2 Hydraulic Circuit Configurations
2.3 Kinetic Analysis of a Braking Vehicle
2.3.1 Equation of Motion
2.3.2 Constant Deceleration Braking
2.3.3 Limits of Deceleration Achieved Purely by  Wheel Braking
2.4 Brake Proportioning and Adhesion Utilisation
2.4.1 Calculation of Static Axle Loads
2.4.2 Dynamic Axle Loads (Load Transfer Effects)
2.4.3 Front Axle Locks First
2.4.4 Rear Axle Locks First
2.4.5 Variation of Braking Force B with Brake Function Z
2.4.6 Braking Efficiency
2.5 Braking with a Variable Braking Ratio
2.6 Effect of Wheel/Axle Locking
2.7 Pitch Motion of the Vehicle Body Under Braking
2.8 Anti-lock Braking Systems (ABS)
2.9 Concluding Remarks
3 Suspension Systems and Components
3.1 Introduction to Suspension Design
3.1.1 The Role of a Vehicle Suspension
3.1.2 Definitions and Terminology
3.1.3 What Is a Vehicle Suspension?
3.1.4 Suspension Classifications
3.1.5 Defining Wheel Position
3.1.6 Tyre Loads
3.2 Selection of Vehicle Suspensions
3.2.1 Factors Influencing Suspension Selection
3.3 Kinematic Requirements for Dependent and Independent Suspensions
3.3.1 Examples of Dependent Suspensions
3.3.2 Examples of Independent Front Suspensions
3.3.3 Examples of Independent Rear Suspensions
3.3.4 Examples of Semi-Independent Rear Suspensions
3.4 Springs
3.4.1 Spring Types and Characteristics
3.4.2 Anti-roll Bars (Roll Stabilisers)
3.5 Dampers
3.5.1 Damper Types and Characteristics
3.5.2 Active Dampers
3.6 Kinematic Analysis of Suspensions
3.7 Roll Centres and Roll Axis
3.7.1 Roll Centre Determination
3.7.2 Roll Centre Migration
3.8 Lateral Load Transfer Due to Cornering
3.8.1 Load Transfer Due to Roll Moment
3.8.2 Load Transfer Due to Sprung Mass Inertia Force
3.8.3 Load Transfer Due to Unsprung Mass Inertia Forces
3.8.4 Total Load Transfer
3.8.5 Roll Angle Gradient (Roll Rate)
3.9 Spring Rate and Wheel Rate
3.9.1 Wheel Rate Required for Constant Natural Frequency
3.9.2 The Relationship Between Spring Rate and Wheel Rate
3.10 Analysis of Forces in Suspension Members
3.10.1 Longitudinal Loads Due to Braking and Accelerating
3.10.2 Vertical Loading
3.10.3 Lateral, Longitudinal and Mixed Loads
3.10.4 Limit or Bump Stops
3.10.5 Modelling Transient Loads
3.11 Suspension Geometry to Combat Squat and Dive
3.11.1 Anti-dive Geometry
3.11.2 Anti-squat Geometry
3.12 Vehicle Ride Analysis
3.12.1 Road Surface Roughness and Vehicle Excitation
3.12.2 Human Perception of Ride
3.13 Vehicle Ride Models
3.13.1 Vibration Analysis of the Quarter Vehicle Model
3.14 Concluding Remarks
4 Steering Systems
4.1 Steering Requirements/Regulations
4.1.1 General Aims and Functions
4.1.2 Statutory Requirements
4.1.3 Steering Ratio
4.1.4 Steering Behaviour
4.2 Steering Geometry and Kinematics
4.2.1 Basic Design Needs
4.2.2 Ideal Ackermann Steering Geometry
4.3 Review of Common Designs
4.3.1 Manual Steering
4.3.2 Rack and Pinion System
4.3.3 Steering Box Systems
4.3.4 Hydraulic Power Assisted Steering (HPAS)
4.3.5 Electric Power Assisted Steering (EPAS)
4.3.6 Steer-by-Wire
4.4 Steering “Errors”
4.4.1 Tyre Slip and Tyre Slip Angle
4.4.2 Compliance Steer—Elastokinematics
4.4.3 Steering Geometry Errors
4.5 Important Geometric Parameters in Determining Steering Forces
4.5.1 Front Wheel Geometry
4.5.2 Kingpin Inclination Angle (Lateral Inclination Angle)
4.5.3 Castor Inclination Angle (Mechanical Castor)
4.6 Forces Associated with Steering a Stationary Vehicle
4.6.1 Tyre Scrub
4.6.2 Jacking of the Vehicle
4.6.3 Forces at the Steering Wheel
4.7 Forces Associated with Steering a Moving Vehicle
4.7.1 Normal Force
4.7.2 Lateral Force
4.7.3 Longitudinal Force—Tractive Effort (Front Wheel Drive) or Braking
4.7.4 Rolling Resistance and Overturning Moments
4.8 Four Wheel Steering (4WS)
4.9 Developments in Steering Assistance—Active Torque Dynamics
4.9.1 Active Yaw Damping
4.9.2 Active Torque Input
4.10 Concluding Remarks
5 Vehicle Structures and Materials
5.1 Review of Vehicle Structures
5.2 Materials for Light Weight Car Body Structures
5.3 Analysis of Car Body Structures
5.3.1 Structural Requirements
5.3.2 Methods of Analysis
5.3.3 Simple Structural Surfaces (SSS) Method
5.3.4 Finite Element Analysis (FEA)
5.4 Safety Under Impact
5.4.1 Legislation
5.4.2 Overview of Frontal Impact
5.4.3 Energy Absorbing Devices and Crash Protection Systems
5.4.4 Case Study: Crashworthiness of Small Spaceframe Sports Car
5.5 Durability Assessment
5.5.1 Introduction
5.5.2 Virtual Proving Ground Approach
5.5.3 Case Study: Durability Assessment and Optimisation of Suspension Component
5.6 Concluding Remarks
6 Noise, Vibration and Harshness (NVH)
6.1 Introduction to NVH
6.2 Fundamentals of Acoustics
6.2.1 General Sound Propagation
6.2.2 Plane Wave Propagation
6.2.3 Acoustic Impedance, z
6.2.4 Acoustic Intensity, i
6.2.5 Spherical Wave Propagation-Acoustic Near- and Far-Fields
6.2.6 Reference Quantities
6.2.7 Acoustic Quantities Expressed in Decibel Form
6.2.8 Combined Effects of Sound Sources
6.2.9 Effects of Reflecting Surfaces on Sound Propagation
6.2.10 Sound in Enclosures (Vehicle Interiors)
6.3 Subjective Response to Sound
6.3.1 The Hearing Mechanism and Human Response Characteristics
6.4 Sound Measurement
6.4.1 Instrumentation for Sound Measurement
6.5 General Noise Control Techniques
6.5.1 Sound Energy Absorption
6.5.2 Sound Transmission Through Barriers
6.5.3 Damping Treatments
6.6 Automotive Noise—Sources and Control
6.6.1 Internal Combustion Engine (ICE) Noise
6.6.2 Transmission Gear Noise
6.6.3 Intake and Exhaust Noise
6.6.4 Aerodynamic Noise
6.6.5 Tyre Noise
6.6.6 Brake Noise
6.7 Automotive Noise Assessment
6.7.1 Drive-By Noise Tests (ISO 362)
6.7.2 Noise from Stationary Vehicles
6.7.3 Interior Noise in Vehicles
6.8 The Sources and Nature of Automotive Vibration
6.9 The Principles of Vibration Control
6.9.1 Control at Source
6.9.2 Vibration Isolation
6.9.3 Tuned Vibration Absorbers
6.9.4 Vibration Dampers
6.10 Engine-Induced Vibration
6.10.1 Single Cylinder Engines
6.10.2 Multi-cylinder Engines
6.10.3 The Isolation of Engine-Induced Vibration
6.11 Braking Systems NVH
6.11.1 Introduction
6.11.2 Brake Noise and Vibration Terminology
6.11.3 Disc Brake Noise—Squeal
6.11.4 Brake Noise Theories and Models
6.11.5 Brake Noise Solutions or “Fixes”
6.11.6 Disc Brake Vibration—Judder and Drone
6.12 Concluding Remarks
Appendix: Summary of Vibration Fundamentals
A.1 Mathematical Models
A.2 Formulating Equations of Motion
A.3 Single Degree of Freedom (SDOF) Systems
A.4 Multi-degree of Freedom (MDOF) Systems
A.4.1 Undamped Systems
A.4 2 Lightly Damped Systems
Bibliography