2.0 Vehicle Dynamics
Ashok jhunjhunwala
Indian Institute of Technology, Madras
Chapter 2.0 Vehicle Dynamics
,Driving an ICE or Electric Vehicle
How much Power is required to drive a vehicle?
How much Energy is required to carry out a road-trip?
◦ What is the composite mass of the vehicle (including passenger and goods): Gross Vehicle
Weight (GVW)
◦ What is the condition of the roads (rolling resistance)
◦ What is the aerodynamics of the vehicle (Aerodynamic drag)
◦ What is the incline that it needs to traverse? (Gradient Resistance)
◦ What are the velocities and accelerations at different points of time (Drive Cycle)
◦ What is the maximum speed and maximum acceleration of the vehicle?
Chapter 2.0 Vehicle Dynamics
, What does tractive force overcomes?
◦ Aerodynamic Drag
◦ Rolling Resistance
◦ Uphill Resistance
◦ Acceleration
Aerodynamic
drag 𝟏
Aerodynamic Drag = *ρ*CD*A*v2
𝟐
◦ v = velocity (m/sec)
Rolling ◦ Air density @27°C = ρ = 1.2 (kg/m3)
Resistance ◦ Vehicle Frontal Area or Projected Area =A (s
θ
◦ Drag coefficient = CD
mg
Chapter 2.0 Vehicle Dynamics
, Forces acting on a vehicle in motion
Aerodynamic
drag
Rolling Resistance = m*g*μ*cosθ
◦ Permissible load = m (kg)
◦ Weight = mg (newton or kg.m/s²), where
= 9.80665 m/s²
Rolling
Resistance p ◦ μ = rolling coefficient
θ
b Uphill Resistance or Climbing Force
mg mg sinθ
◦ Maximum grade = θ° = θ*π/180 radians
Grade/Inclination:
Height of grade p
Grade in % = *100 % = *100 %
Base of the grade b
𝑝 Tractive force created by power-train first ov
Grade in Degree = 𝑡𝑎𝑛−1 𝑏
these resistances and then provides accelera
Chapter 2.0 Vehicle Dynamics
Ashok jhunjhunwala
Indian Institute of Technology, Madras
Chapter 2.0 Vehicle Dynamics
,Driving an ICE or Electric Vehicle
How much Power is required to drive a vehicle?
How much Energy is required to carry out a road-trip?
◦ What is the composite mass of the vehicle (including passenger and goods): Gross Vehicle
Weight (GVW)
◦ What is the condition of the roads (rolling resistance)
◦ What is the aerodynamics of the vehicle (Aerodynamic drag)
◦ What is the incline that it needs to traverse? (Gradient Resistance)
◦ What are the velocities and accelerations at different points of time (Drive Cycle)
◦ What is the maximum speed and maximum acceleration of the vehicle?
Chapter 2.0 Vehicle Dynamics
, What does tractive force overcomes?
◦ Aerodynamic Drag
◦ Rolling Resistance
◦ Uphill Resistance
◦ Acceleration
Aerodynamic
drag 𝟏
Aerodynamic Drag = *ρ*CD*A*v2
𝟐
◦ v = velocity (m/sec)
Rolling ◦ Air density @27°C = ρ = 1.2 (kg/m3)
Resistance ◦ Vehicle Frontal Area or Projected Area =A (s
θ
◦ Drag coefficient = CD
mg
Chapter 2.0 Vehicle Dynamics
, Forces acting on a vehicle in motion
Aerodynamic
drag
Rolling Resistance = m*g*μ*cosθ
◦ Permissible load = m (kg)
◦ Weight = mg (newton or kg.m/s²), where
= 9.80665 m/s²
Rolling
Resistance p ◦ μ = rolling coefficient
θ
b Uphill Resistance or Climbing Force
mg mg sinθ
◦ Maximum grade = θ° = θ*π/180 radians
Grade/Inclination:
Height of grade p
Grade in % = *100 % = *100 %
Base of the grade b
𝑝 Tractive force created by power-train first ov
Grade in Degree = 𝑡𝑎𝑛−1 𝑏
these resistances and then provides accelera
Chapter 2.0 Vehicle Dynamics
