Vehicle Dynamics

Course objectives:
To understand a foundation of engineering principles and analytical method to explain the performance of an automotive vehicle, concerning acceleration performance, braking performance, aerodynamics and rolling resistance, ride, tire dynamics, suspension system, steerability, stability, cross country ability and smoothness running of an automotive vehicle

1. Fundamentals of a motor vehicle(4 hours)
1. History of vehicle dynamics
2. Modeling of a vehicle
3. Modeling approaches: lumped mass, vehicle coordinate system, earth fixed coordinate system
4. Forces acting on a motor vehicle
5. Tractive forces on the driving wheels
6. Transmission efficiency
7. Traction characteristics of a motor vehicle
8. Road resistance (total road loads), air resistance, rolling resistance
9. Equation of a motion of a motor vehicle
10. Tractive forces according to conditions of tire road grip
11. Normal reactions of the road


2. Traction dynamics of a motor vehicle(4 hours)
1. Force and power balance
2. Dynamic axle loads
3. Load transfer during acceleration, braking, constant velocity motions, conditions of traction
4. Layout analysis as front engine, rear engine
5. Front wheel and rear wheel drive


3. Aerodynamics of a motor vehicle(2 hours)
1. Mechanics of air flow and pressure distribution on a vehicle
2. Aerodynamic forces, drag components
3. Aerodynamic aids
4. Drag side force, lift force
5. Pitch, yawing and rolling moment
6. Crosswind sensitivity


4. Dynamic performance of a motor vehicle(4 hours)
1. Dynamic factor, dynamic characteristic of motor vehicle
2. Power limited acceleration based on: engines, power train & final drive ratio, automatic transmission
3. Traction limited acceleration (transverse weight shift due to drive torque, traction limits)
4. Acceleration due to traction force
5. Gradient climbing, coasting, overtaking


5. Fuel economy of a motor vehicle(2 hours)
1. Fuel economy characteristics
2. Fuel consumption equation
3. Effect of operating factors on fuel economy
4. Fuel consumption rate


6. Braking dynamics of a motor vehicle(6 hours)
1. Introduction to braking dynamics
2. Basic equations of motion of a motor vehicle: constant deceleration with wind resistance
3. Braking properties of a motor vehicle, braking forces on wheels
4. Equation of motion of a motor vehicle during braking
5. Characteristics of a motor vehicle braking dynamics :braking deceleration, braking time and braking distance
6. Braking force distribution between the wheels
7. Brakes factor
8. Tyre road friction
9. Requirements for braking performance, braking proportioning
10. Rear wheel lock up, pedal force gain
11. Braking methods, braking efficiency
12. New features in the design of brake systems


7. Stability of a motor vehicle(3 hours)
1. Lateral stability characteristics
2. Body lateral rolling
3. Effect of operating factors on lateral stability
4. Longitudinal stability


8. Steerability of a motor vehicle(6 hours)
1. Steerability characteristics, force analysis during steering
2. Rolling of the steerable wheels without slipping
3. Wheel lateral slip and ability of a motor vehicle to turn
4. Four wheel steer: low speed turning, high speed cornering
5. Relation between angles of turn of steerable wheels
6. Oscillations and stabilisation of the steerable wheels


9. Tyre dynamics(4 hours)
1. Tyre construction
2. Size and load rating
3. Tyre axis system
4. Tire forces and moments
5. Longitudinal and lateral force at various slip angle, rolling resistance
6. Tractive and cornering properties of tyre
7. Performance of tyre on wet surfaces
8. Ride properties of tyre
9. Road friction
10. Test on various surfaces
11. Effect of various parameters on tractive properties


10. Suspension system(6 hours)
1. Human response to vibration, sources of vibration
2. Design and analysis of passive, semi active and active suspension using quarter car, bicycle model, half car and full car model
3. Independent suspension
4. Influence of suspension stiffness, suspension damping and tire stiffness
5. Air suspension system and their properties
6. Roll centre analysis


11. Cross country ability of a motor vehicle(2 hours)
1. Cross country
2. Trafficability requirements, trafficability test
3. Geometrical and tractive characteristics of trafficability
4. Effect of a motor vehicle design on its cross-country ability


12. Smooth running of a motor vehicle(2 hours)
1. Smooth running and its testing
2. Characteristics of the smoothness of run
3. Oscillations of a motor vehicle
4. Effect of design factors on smooth running
5. Future developments of motor vehicle design

Practical

1. Term paper on vibration applied to vehicle
2. Vehicle Power test by Chasis Dynamometer
3. Case Study on vehicle dynamics test

References:

1. M. D. Artamonov, V. A. Ilarionov, M. M. Morin, Motor Vehicles, Fundamentals and design, Mir Publishers, Moscow, 1976.
2. Dr. Thomas Gillespie, SAE Publications.
3. William H. Crouse, Donald L. Anglin, Automotive Mechanics, McGraw Hill education Private Limited.
4. Reza N. Jazar, “Vehicle dynamics Theory and application”, Springer
5. Wong, Jo Yung, “Theory of ground vehicle”, John Wiley & Sons.
6. N. K. Giri, “Automotive Mechanics”, Khanna Publishers
7. Anil Chikara, “Automobile System”, Satya Prakashan
8. Stead, “Mechanics of road vehicles”, TMH

Evaluation scheme
The questions will cover all the chapters of the syllabus. The evaluation scheme will be as indicated in the table below: