Engine and Vehicle Design and Performance

Engine and Vehicle Design and
Performance
Done by:
Contents
TASK 8..........................................................................................................................................................1
TASK 9..........................................................................................................................................................4
TASK 10........................................................................................................................................................7
TASK 11.....................................................................................................................................................11
References:................................................................................................................................................13

TASK 8
A. Write an equation for Performance loss terms of a Vehicle:
The Performance of an Automobile depends upon various factors such as vehicle
resistance, coefficient of friction, the contact area of the wheel to the surface, engine
capacity, gearbox ratios, etc.
In this session the Vehicle Resistance characteristic of a vehicle and the terms
associated with it will be explained:
The Vehicle Resistance comes into play while designing a transmission system for
Automobiles. In general, the Vehicle Resistance Characteristics depends upon the four
terms such as (Hooftman, et al, 2018):
1. FL : Air Resistance.
2. Fst : Gradient Resistance.
3. FR : Rolling Resistance of the wheel.
1. FL Air Resistance:
The Air resistance Force can be calculated as:
FL=0.5 ρ Cd A v2
Where,
FL is the Air drag in N
ρ is the Density of the fluid (air) in Kg/m3
Cd is the Coefficient of drag
A is the frontal area of the moving object. In m
V is the Velocity of the car in m/s
2. Fst, Gradient Resistance:

The Gradient Resistance can be mathematically expressed as:
Fst=M v . g .sin Gst
Where,
Mv is the Mass of the Vehicle in Kg
g is the Acceleration due to gravity in m/s2
Gst is the slope of the track in degrees.
3.Rolling Resistance of a vehicle:
Mathematically Rolling resistance can be termed as:
FR =C . Mg
Where,
C is the Rolling resistance coefficient
M is the mass of the vehicle in Kg
g is the Acceleration due to gravity in m/s2
B.
1. Air Resistance:
Whenever an object moves in a fluid medium, the Fluid medium will excert an opposing
friction force on that object. This opposing friction force is known as air resistance or air
drag. The drag force increases the Fuel consumption of a car, it is important to design
the car in a most aerodynamic way (tendency to withstand drag force and to avoid
turbulent end conditions). The air drag of a vehicle must be taken into consideration
while designing the vehicle (Hooftman, et al, 2018).

2. Gradient Resistance:
Whenever an automobile moves uphill or downhill, a resistive force is acted on the
vehicle, which is known as force due to gravity or Gradient Resistance. It occurs due to
the weight acting at the centre of gravity of the vehicle (Bian and Qiu, 2018) (Babu,
2015).
3. Rolling Resistance:
The rolling resistance is the amount of force that resists the motion of a body when it
rolls on a surface. In case of a car rolling resistance acts on the wheel, the tire must be
capable of overcoming the resistance offered by the road surface to set the vehicle in
motion (Hu, et al, 2017) (burns, et al, 2017)
TASK 9
Given data:
First Gear Ratio: 2.95
2nd Gear Ratio: 2.50
3rd Gear Ratio: 1.99
4th Gear ratio: 1.42
5th Gear ratio: 0.9
Differential Ratio: 3.48
Overall Transmission efficiency: 87 %
Wheel Radius: 0.36 m
The different Torque can be found at: