Solar car Design Report

TEAM HORUS| NMIT| ISVC2018044| 1
CHAPTER 1
INTRODUCTION
1.1 About TEAM HORUS
The team is group of 25 enthusiastic engineers who aim to innovate a sustainable technology
by incorporating the infinite source of solar energy into automotive world.
Our vital aim is to design a solar vehicle which sets new standards and breaks existing
records for functionality, efficiency and sustainability for a future in which renewable sources
will represent the façade of automotive industry.
With zeal and spirit, we give rise to reality with our ideas and effectively use technology to
exude creativity utilizing our strengths and knowledge.
The team hopes to show case their hidden talents among international professionals and
universities of india.
Virtual round Obtained marks Max marks
Rule book 18 20
Specs 90 100
Design 46 50
System 45 50
DFMEA 48 50
DVP 37 40
Project plan 28 30
Cost report 70 80
Skills 46 50
Innovation 74 80
Total 542 600
1.2 Renewable Energy
Renewable energy is the energy that is collected from renewable sources or resources which
are naturally replenished on a human time scale such as sunlight, wind, rain and geothermal
heat. Renewable energy often provides energy in four important areas: electricity generation,
air and water heating/cooling, transportation and rural energy services.
Renewable energy plays an important role in reducing greenhouse gas emissions. When
renewable energy sources are used, the demand for fossil fuels is reduced. Unlike fossil fuels,

non-biomass renewable sources of energy (hydropower, geothermal, wind, and solar) do not
directly emit greenhouse gases.
India has the fifth largest power generation portfolio in the world and its current renewable
energy contribution stands at 44.812 GW.
Fig 1.1: Renewable Energy Sources
1.3 Scope of Solar Energy
The quests for a constant, safe, clean, environmental-friendly fuel is never-ending. Carbon-
based fuels, such as fossil fuels are unsustainable and hazardous to our environment. Some of
the alternatives are renewable energy sources which include all fuel types and energy carriers,
different from the fossil ones, such as the sun, wind, tides, hydropower and biomass.
Amongst these elements, solar energy is preferred since it could provide the cleanest
sustainable energy for the longest duration of time – the next few billion years.
Generation of solar energy has tremendous scope in India. The geographical location of the
country stands to its benefit for generating solar energy. The reason being India is a tropical
country and it receives solar radiation almost throughout the year. Thus, India has massive
plan for solar energy generation that may not only fulfil the deficit of power generation but
also contribute largely in green energy production.
Nothing on earth is free of cost, but what if we could find a way to implement free rides?
Indeed, it would be wonderful if our cars could continue to run without us having to spend
billions on fossil fuels every year and to deal with natural hazards that their combustion leave
behind. If we could drive a solar-powered car, that auto dream would come true. Solar cars
would harness energy from the sun via solar panels. A solar panel is a packaged, connected
assembly of solar cells, also called photovoltaic cells which are solid state devices that can
convert solar energy directly into electrical energy through quantum mechanical transitions.
They are noiseless and pollution-free with no rotating parts and need minimum maintenance.
The electricity thus generated would then fuel the battery that would run the car's motors.
Therefore, would obtain an electrically driven vehicle that would travel on sustainable source

of energy with no harmful emissions, that can utilize its full power at all speeds, and would
have very little maintenance cost.
Fig 1.2: Growth of Solar and Wind energy in India
1.4 Principle of PV Cells
Fig 1.3: PV Cells
Conversion of light energy in electrical energy is based on a phenomenon called photovoltaic
effect. When semiconductor materials are exposed to light, the some of the photons of light
ray are absorbed by the semiconductor crystal which causes significant number of free
electrons in the crystal. This is the basic reason of producing electricity due to photovoltaic
effect. Photovoltaic cell is the basic unit of the system where photovoltaic effect is utilized to
produce electricity from light energy. Silicon is the most widely used semiconductor material
for constructing photovoltaic cell.

A typical Silicon PV cell is composed of a thin wafer consisting of an ultra-thin layer of
phosphorus-doped (n-type) silicon on top of a thicker layer of boron-doped (p-type) silicon.
An electrical field is created near the top surface of the cell where these two materials are in
contact, called the p-n junction. When sunlight strikes the surface of a PV cell, this electrical
field provides momentum and direction to light-stimulated electrons, if the intensity of
incident light is high enough, sufficient numbers of photons are absorbed by the crystal and
these photons in turn excite some of the electrons of covalent bonds. These excited electrons
then get sufficient energy to migrate from valence band to conduction band. As the energy
level of these electrons is in conduction band they leave from the covalent bond leaving a
hole in the bond behind each removed electron. These are called free electrons move
randomly inside the crystal structure of the silicon. These free electrons and holes have vital
role in creating electricity in photovoltaic cell. These electrons and holes are hence called
light-generated electrons and holes respectively.
1.5 Applications
KyRa is convenient electric vehicle with augmented range due to its solar modules for
travelling short distances at reasonable speeds. Due to its light weight and crisp handling,
KyRa handles all kinds of roads effortlessly.
The solar panels used in our vehicle is monocrystalline type because:
 Longevity
 Efficiency
 Low installation cost
 Embodied energy
 Great heat resistance
 More electricity

1.7 Car Specifications
GENERAL SPECIFICATIONS DESCRIPTION
Overall Length (inch): 143.5”
Wheelbase (inch): 70.866”
Track Width (inch)(front): 55.11”
Weight without Driver (kg): 155 kg
C.G Height (inch) : 16.929”
Ground Clearance (inch): 7”
Drive train Hub motor driven wheel
Steering System Ackerman’s steering mechanism
Electrical System Hub motor controlled using
microcontrollers
Solar System Photovoltaic monocrystalline
cells
Braking System Hydraulic
Tires/Wheels 4 wheels, rear wheel driven.
Material Of Chassis Chrome molybdenum steel 4130
& aluminum
Using Seat Belt & lock nuts Yes

CHAPTER 2
CHASSIS AND BODYFRAME
2.1 Introduction
The chassis of any automotive vehicle has to connect all wheels with a structure, which is
rigid in bending and torsion. It must be capable to support all the components along with the
driver and should absorb all the loads fed into it without deflecting unduly. A well-designed
chassis is designed in a way to accommodate all components in the best possible way and
distribute the loads in the best way possible. To make sure that the safety of the driver is our
main priority, the rules imposed by ISVC are strictly followed while designing the chassis.
2.2 Goals
1. To ensure that all systems fit into the chassis.
2. To minimize the weight to stiffness ratio.
3. To maintain low centre of gravity.
4. To select an appropriate material for the chassis.
5. To create a solid base chassis this will evolve in the years to come.
Fig 2.1 Isometric view
Fig 2.2: Side View
Fig 2.3: Front View

2.3 Chassis Requirements
Material should be certified from any of the recognized material testing laboratories for its
chemical and mechanical properties. The mountings and designing of chassis should be such
that there should be minimum 2 inches clearance between the driver and any component of
the vehicle in static and dynamic condition.
2.4 ISVC Rulebook Requirements
The vehicle can have (4) wheels or (3) wheels but not in a straight line. The wheelbase will
be measured from the centre of contact on ground of the front to rear tires with the wheels
pointed straight ahead. The mountings and designing of chassis should be such that there
should be minimum 2 inches clearances (gap) between the driver and any component of the
vehicle in static and dynamic condition – hands, torso, thigh etc. Holes in chassis are not
permitted.
2.5 Considerations
Maximum surface area, minimum linkages, maximum driver area, tried to cover less weight
and designed in a way that the solar panels have exposure to direct sunlight.
2.6 Dimensions
Decimal values are rounded off to the nearest values for further calculations.
Wheel base 1.8m
Overall length 3.64m
Overall width 1.76m
Front Track
width
1.4m
Rear track width 1.5m
Extensions 0.5m
2.7 Material Selection and Tubing Requirements
The factors contributing to the selection of the material are many but the most important one
is the availability. There is no point in considering those factors if the alloy or grade of
material is not available in the market. So keeping this in mind, a list of materials that are
desirable was prepared.
1) Steel
Steel is the most commonly used material for tubular frames. It retains its strength and
ductility even after welding. It is inexpensive and easy to find and also easy to cut and grind.
The tubing sizes have been met with the rules specified. Because of all these reasons and its
high yield strength, steel has been chosen for our tubular frame. In particular we are selected
chrom-moly steel 4130. It is widely used in the aviation, racing and cycling industries
because it has an excellent strength to weight ratio, it is very malleable and it is very easy to
weld. 4130 chromoly, alloy steel tube, is resistant to scaling and oxidation and has a clean,

smooth finish on both the inside and the outside of the tubing. Properties of this particular
steel are,
2) Mild or Low-Carbon Steel
For extension we used mild steel, also known as plain-carbon steel and low-carbon steel, is
now the most common form of steel because its price is relatively low while it provides
material properties that are acceptable for many applications. Mild steel contains
approximately 0.05–0.25% carbon making it malleable and ductile. Mild steel has a relatively
low tensile strength, but it is cheap and easy to form; surface hardness can be increased
through carburizing.
In applications where large cross-sections are used to minimize deflection, failure by yield is
not a risk so low-carbon steels are the best choice, for example as structural steel. The density
of mild steel is approximately 7.85 g/cm3
(7850 kg/m3
or 0.284 lb/in3
) and the young's
modulus is 200 gpa (29,000 ksi).
Low-carbon steels suffer from yield-point runout where the material has two yield points.
The first yield point (or upper yield point) is higher than the second and the yield drops
dramatically after the upper yield point. If a low-carbon steel is only stressed to some point
between the upper and lower yield point and the surface develop lüder bands. Low-carbon
steels contain less carbon than other steels and are easier to cold-form, making them easier to
handle.
2.8 Chassis Analysis
Structural analysis plays a very important role in comparing the results with theoretical
calculations. The analysis was done in Ansys workbench.
Calculations
Mass of the car: 220 kg
V= 50 kmph= 13.88 m/s, T= 0.1 s
Acceleration= a= 13.88/0.1
F= 300*138.8= 41640 N

Frontal loading
Frontal impact has been done considering the car top speed as 50 kmph and undergoing head
on collision with a rigid body. 2g force was considered. Load was equally distributed on each
member. Load of 4500 N was applied on every member.
Rear Impact
The considered speed was 50 kmph and 2g force was considered .the rear impact test was
done by fixing the frontal parts and applying the load at the rear part.
Total load was equally distributed on each member of the chassis at the rear part A load of
3142 N was applied on each member, maximum stress, total deformation, factor of safety ,
stress intensity were determined.
Fig 2.5 Maximum Stress Fig 2.6 Total Deformation
Fig 2.7 Factor of Safety Front Fig 2.8 Stress Intensity Front
Fig 2.11 Factor of Safety Rear Fig 2.12 Stress Intensity Rear

Side Loading
Load was equally distributed on one side of the chassis. Load of 2750 N was applied on
every member in the side. Maximum stress, total deformation, factor of safety and stress
intensity was determined.
2.8.1 Analysis Data
SPECIFICATIONS FRONT REAR SIDE
Load applied 4500 N 3142 N 2750 N
Maximum stress 182.07 M Pa 124.3 MPa 85.798 MPa
Maximum
deformation
1.6887 mm 1.7987 mm 0.41526 mm
Factor of safety 0.47346-15 0.69349-15 1.0047-15
Max Stress
intensity
201.11 MPa 98.811 MPa 138.27 MPa
2.9 Body Frame
2.9.1 Materials used:
1. Outer covering: Aluminium Composite Panels (3mm)
2. Chassis covering: Clear polycarbonate sheets (3mm)
3. Solar Panel Base: Styrofoam
4. Baseplate: Aluminium sheets (3mm)
Fig 2.13 Maximum Stress Side Fig 2.14 Total Deformation Side

Fastening methods: bolt and nut, bending wire and zip ties.
2.9.2 Features:
1. Aluminium Composite Panels: Aluminium composite panels (ACP), made of
aluminium composite material (ACM), are flat panels consisting of two thin coil-
coated aluminium sheets bonded to a non-aluminium core. ACP is mainly used for
external and internal architectural cladding or partitions, false ceilings, signage,
machine coverings, container construction, etc.
Characteristics: The qualities that have produced the rapid growth in the use of ACP
include: cost, durability, efficiency, flexibility, low weight, and easy forming and
processing allow for innovative design with increased rigidity and durability.
2. Polycarbonate sheets: Polycarbonates (PC) are a group of thermoplastic polymers
containing carbonate groups in their chemical structures. Polycarbonates used in
engineering are strong, tough materials, and some grades are optically transparent.
They are easily worked, moulded, and thermoformed.
Properties: Polycarbonate is a durable material. Although it has high impact-
resistance, it has low scratch-resistance. Polycarbonate will hold up longer to extreme
temperature. Polycarbonate is highly transparent to visible light, with better light
transmission than many kinds of glass. It can undergo large plastic deformations
without cracking or breaking. As a result, it can be processed and formed at room
temperature using sheet metal techniques, such as bending on a brake. Even for sharp
angle bends with a tight radius, heating may not be necessary.
3. Styrofoam: Styrofoam is a trademarked brand of closed-cell extruded polystyrene
foam (XPS) manufactured as foam continuous building insulation board used in walls,
roofs, and foundations as thermal insulation and water barrier. It provides cushioning
effect for the solar panels that helps avoid any breakage due to impact.
4. Aluminium sheets: Aluminium is remarkable for its low density, light weight, low
cost, high strength to weight ratio and its ability to resist corrosion. It also has good
machinability for wide range of application. It is used as the baseplate of the chassis.

CHAPTER 3
STEERING SYSTEM
3.1 Introduction
Steering is the collection of components, linkages, etc. which allows any vehicle to follow the
desired course. Type of steering used is Ackerman’s steering as it is simple to construct and it
is widely used in the modern automotive industry
3.2 Basic Design Features
Steering system used for our vehicle is rack and pinion type.
 It provides better precision as it has fewer parts and pivot joints, hence easier to
control.
 Lighter in weight as number of parts are reduced.
 Gives good road feel- quicker and better feedback.
 Easier to repair.
 Cost effective.
Primary factors which we considered were low weight and proper suspension geometry.
Availability, ergonomics, low backlash and chassis constraints were all high priority
secondary considerations.
3.3 Main Components of Steering System:
Steering shaft, steering rack and tie rods. Rack and pinion gear set is enclosed in a metal tube
.tie rods connect to each end of the rack. Pinion gear is attached to steering shaft. When the
steering wheel is turned, gear spins, moving the rack. Tie rods at each end connects to
steering arm.
Rack and pinion gear set:
1. Converts rotational motion of steering wheel into linear motion needed to turn the wheels.
2. Provides gear reduction hence, turning of wheels are easier.
3.4 Goals
 To improve overall handling of the car.
 To provide considerable and appropriate feedback to the driver.
 To incorporate large amount of positive Ackermann geometry for the car.
 To minimize driver effort.
3.5 ISVC Rulebook Specifications:
1. Must be able to control at least two wheels.
2. Must have a positive steering stop that prevents the steering linkages from locking up
either in RH or LH turning.

3. Must prevent the tires from contacting the body or frame members during the dynamic
events.
4. Allowable total steering system free play is limited to 7 degrees, measured at the
steering wheel.
5. Steering wheel must be mechanically connected to the front wheels.
3.6 Steering System Parameters
Parameters Steering system(Ackerman’s steering)
Number of teeth on rack 32
Diameter of pinion 27mm
No of teeth on pinion 12
Pressure angle 20 degrees
Modulus of rack and pinion 1.5
Addendum 1.5mm
Dedendum 1.875mm
Rack shaft length 43 inches
Steering rack location 21inches(from ground)
Rack length 24 inches
Maximum steer angle of inside wheel 40°
Maximum steer angle of outside wheel 35°
Maximum turning radius 2.7 m
Steering wheel diameter 300 mm
Torque on steering wheel 45 N-m
Steering ratio 7:1
3.8 Calculations
Ackerman steering
When the vehicle turns, the inner front wheels and outer wheels turn at different angles as
they turn at different radii. Ackerman steering mechanism is geometric arrangements of
linkages in the steering which helps the inner and outer wheels turn at different angles.
Ackerman results when the steering is done behind the front axle and the steering arms points
the center of the rear axle.
1) Turning radius :
⍬=40ᴼ; α=35ᴼ ; b=1.7m ; k=1.1m ; t=1.4m;
T1 = [b/(sin⍬)] –[(t-k)/2] =2.4 m
T2 =[b/(sinα)] +[(t-k)/2] =3.0 m

2) Average turning radius =2.7m
3) Ackerman angle = tan [(kingpin distance/2)]/ (wheel base)
= tan [(1.1/2)/(1.7 )]
=19.5°
4) Steering wheel torque calculations:
T= kingpin torque
W= axle weight = 2kg
µ= co efficient of friction =0.7
𝐵= width of the tyre =3.5’’
E=kingpin offset=74mm(2.9’’)
T= W µ√[(B2
/8)+ E2
]
=2(0.7)√(88.9)2
/8+(74)2
] =103.70 Nm
5) Gear ratio
=driven/drive =32/12 = 2.66
6) Torque at pinion
= (103.7*1.6)/27 =10.21 N-mm
7) Torque at steering wheel:
T=F*R
F assume 150N
R=0.15 m
T= F 1 r1 +F2r2 =22.5+22.5 =45 N-m

CHAPTER 4
SUSPENSION
4.1 Introduction
Suspension being the most important part of the car, gives a better road holding and better
ride comfort for the driver. The fundamental principle of suspension is to keep the wheels in
contact with the ground and maintain the stability in all kinds of situation.
4.2 Goals
 Design and create a suspension system which satisfies or meets the requirements of
the ISVC rule book.
 To provide good ride and handling performance
– Vertical compliance providing chassis isolation
– Ensuring that the wheels follow the road profile
 To ensure that steering control is maintained during manoeuvring
– Wheels to be maintained in the proper position w.r.t road surface
 To ensure that the vehicle responds favourably to control forces produced by the tires
during
– Longitudinal braking
– Accelerating forces
– Lateral cornering forces and
– Braking and accelerating torques.
4.3 ISVC Rulebook Specifications:
 Suspension system should have minimum travel of 1 inch.
 The suspension system must be rigid.
4.4 Telescopic Suspension:
The telescopic suspension serves a dual purpose: contributing to the vehicle's handling and
braking, and providing safety and comfort by keeping the vehicle's passengers comfortably
isolated from road noise, bumps and vibrations.
A shock absorber is a mechanical or hydraulic device designed to absorb and damp shock
impulses. Hydraulic shock absorbers are used in conjunction with cushions and springs. An
automobile shock absorber contains spring-loaded check valves and orifices to control the
flow of oil through an internal piston. Telescoping shock absorber is a type of hydraulic
shock absorber.
Construction of telescopic shock absorber: -It consists of an outer tube, which is attached
to suspension system of the automobile. Inner tube is placed inside the outer tube which acts

as a working cylinder for the piston that is attached to a piston rod. Other end of this piston
rod is attached to chassis flame. Piston is provided with two-way valve which is also attached
to the base of outer tube. Viscous fluid is filled inside the inner tube. Viscous fluid also filled
in the angular space of inner and outer tube. This viscous fluid is maintained in such a way
that there is air space left above the fluid.
Working of telescopic shock absorber:-When automobile vehicle comes across a bump, the
outer tube moves up which increase the pressure between 2-way valves. This high pressure
opens the valve assembly in the piston thus allowing fluid to moves in upper chamber of
inner tube. Also this pressure opens the valve assembly in base of inner tube thus allowing to
some fluid to moves in angular space.
Similarly, when automobile vehicle comes across from pot hole, outer tube moves down thus
decreasing pressure between both 2-way valves. This low pressure opens the valve assembly
in piston. This allows the fluid to flow from upper chamber to downward. Also this decreases
pressure, opens the valve assembly in base of inner tube and allowing fluid to flow in angular
space. This passing of fluid through valve opening provides damping. This includes the
working of shock absorber.
Advantages of telescopic shock absorber:-
 One of the advantages of a twin-tube gas pressurized shock is that less gas pressure
can be used to prevent the fluid from foaming.
 No need to have a highly polished piston bore with a floating piston which results in
lowers manufacturing costs.
 More latitude in shock valving for a wider range of control compared to a
conventional shock.
 The telescopic shock absorber is also less expensive to manufacture than a
conventional shock absorber.
Fig 4.1: Suspension System

4.5 Tires
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's
load from the axle through the wheel to the ground and to provide traction on the surface
travelled over. Most tires, such as those for automobiles and bicycles,
are pneumatically inflated structures, which also provide a flexible cushion that absorbs
shock as the tire rolls over rough features on the surface. Tires provide a footprint that is
designed to match the weight of the vehicle with the bearing strength of the surface that it
rolls over by providing a bearing pressure that will not deform the surface excessively. In the
rear side, the tires are incorporated with the hub motor.
Tires selected : front tire is 12 inches and rear tire is 10 inches.
Tire size (front): 90/90-r12
Tire size (back):90/100-r10
4.6 Wheel Base
Shorter the wheelbase, more responsive is the car during all dynamic situations. The
minimum wheelbase that would be attainable with the selected power train and taking into
consideration the rules for driver cockpit would be.
Wheel base = 1.8m
4.7 Track Width
Wider track width is better for maximizing cornering g-force without rolling over. Narrow
track width is better for fitting between obstacles, if the criterion involves negotiating a
slalom, the increased cornering g’s allowed by a wide track width may be neglected by the
vehicle having to go much further side to side in order to negotiate the slalom.
Also higher track widths can lead to unusual load transfers in the car while cornering for
higher C.G heights. Thus decided track widths are
Front track width = 1.4m
Rear track width = 1.5m
4.8 Telescopic Forks
Telescopic forks are used for the front suspension. The forks can be most easily understood
as simply large hydraulic shock absorbers with internal coil springs. They allow the front
wheel to react to imperfections in the road while isolating the rest of the car from that motion.
The top of the forks are connected to the car's frame in a triple tree clamp which allows the
forks to be turned in order to steer the motorcycle. The bottom of the forks is connected to the
front wheel's axle.

4.9 Parameters
The parameters involved in suspension system are given below:
Parameters Dimensions Design
Arms
Fig 4.2: Arms
Active fork Length: 10.5”
Diameter: 4.3
cm
Fixed fork Length: 5.5”
Diameter: 3.83
cm
Bearings
Inner ring
diameter
4 cm
Fig 4.3: Bearings
Outer ring
diameter
6 cm
Seal diameter 2 cm
Height 6cm
T fork
Fig 4.4: T Fork
Length 13.5”
Diameter 1”
T plate
Fixed
fork
diameter
1”
Length 11.25”
Width 3”
Depth 1.25”
A arm

Length 9.25”
Fig 4.5:
A Arm
Diameter 1”
Locking
screw
diameter
10 mm
Bushing
diameter
8 mm
Fixture
diameter
25.4
mm
4.10 Dampers and Clamps
Springs and dampers are important elements of suspension and are the key element to
supporting and balancing the forces that the a-arm will be suffering. Shocks will be
connected to the bottom a-arm via a push rod for the front suspension, thus mounting will be
considered while analysing stresses. The rear suspension will use the pushrod style where the
link connects to the upper a-arm. The connection to the a-arm will also determine the travel
of the wheel assembly.
Clamp is a device used to join, grip, support, or compress mechanical or structural parts. U
clamps are used in the suspension. Between the A arm and the suspension fork, U clamps are
connected because to have a degree of freedom (movement) of A arm. If the connection
between the suspension fork and the A arm is welded then, A arm won’t move freely.
4.11 Suspension Travel
Suspension system has a travel of 2 inch.
4.12 Analysis of A -Arm
The car will be travelling on an even terrain therefore while analysing suspension two major
forces will be dealt with: cornering and braking. Lateral force is the force exerted on the tire
contact patch as the vehicle turns and the weight of the vehicle shifts towards one side. The
braking force is the force on the tire contact patch created when the weight distribution of the
car shifts to the forward steering knuckle as the car brakes. To calculate forces due to
cornering, one must understand the forces created as the car pushes against the road, thus
friction comes into play. For the braking force, similar calculations have been done. As the
vehicle brakes, the brake calliper will force the brake pads onto the brake disc so as to stop its
motion.

Properties of chromoly and mild steel are as follows:
Properties Chromoly – a-arms
Density 7850kgm-3
Modulus of elasticity 210gpa
Yield strength 460mpa
Ultimate tensile strength 560mpa
The analysis was carried by considering 2.5g bump force, 1.5g lateral force and 3g brake
force.
Fig 4.6: Total Deformation: Max total deformation: 0.007587 mm
4.12 Why telescopic suspension?
We used telescopic suspension because of the following reasons:
 To reduce the weight of the vehicle
 To protect the solar panel
 For innovation purpose
 To reduce the number of moving parts
 To ensure driver’s safety
CHAPTER 5
BRAKES
5.1 Introduction
Brake is a mechanical device which inhibits motion. It is used for slowing or stopping a
moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of
friction.
Braking system is a vital part of the vehicle that stops the vehicle according to the driver’s
will and also help in manoeuvring the vehicle at an easier rate. It is used for the safety

purpose and helps in avoiding fatal accidents due to high speeds. The efficiency of the
braking system is one of the key parameters of the vehicle performance.
5.2 Goals
The purpose of this project is to design a braking system for the solar vehicle which produces
adequate braking force to meet competition regulations and also being as light weight as
possible. The system should also limit un-sprung weight to help improve maneuverability.
Some of our specific goals are:
 All wheels lock on application of brakes.
 Safe and easy application of brakes by the driver.
 Automatic power kill upon extra pedal travel
5.3 ISVC Rulebook Specifications
 Car must be equipped with a braking system that acts on at least one of the axles either
front or back and brake installed must be capable of stopping the vehicle in a straight
line without losing control during the brake test.
 The vehicle must have hydraulic braking system and the pedal must actuate the master
cylinder through rigid link.
 All brake lines must be securely mounted and not fall below any portion of the vehicle.
 Pedals must never protrude forward of the chassis including bumpers. Pedal footrest
must be provided. Pedals should not tend to bend on the application of force during
dynamic events. Pedal size should be according to the driver’s foot and should have
minimum area of 25 sq. Cm.
 The vehicle must be installed with a brake light red in color which is clearly visible from
the rear. If an led brake light is used, it must be clearly visible in very bright sunlight.
This light must be mounted between the wheel centerline. All the electrical connections
done must be well insulated and should be tied properly.

5.4 Design Specifications
Fig 5.1: Disc Brake Configuration
1. For our design we have chosen to use a front/rear split as it is easier to route and
helps us in calculations.
2. We have also emphasized on using a single tandem master cylinder for easier
bleeding and lesser weight. The bore size of the master we are using is 3/4th inch and its
stroke being 76mm.
3. We are using a disc brake system. Disc brakes are generally considered superior to
drum brakes for several reasons:
i. Disc brakes perform better in wet weather, because centrifugal force tends to fling
water off the brake disc and keep it dry, whereas drum brakes will collect some water on
the inside surface where the brake shoes contact the drums. For our application i believe
disc brakes are going to work much better than drum brakes ever could. We are going to
endure a long, rough, and wet endurance course that will put our braking system through
a lot of challenges. From the research it is easy to see that disc brakes will work much
better for this application for many reasons.
ii. The first reason being that disc brakes offer superior braking force to drum brakes.
For our competition the braking system must lock up all four wheels simultaneously on
dry tarmac.
iii. The second reason disc brakes are going to work better for our application is that
disc brakes can dissipate heat better than drum brakes can. This is going to be a key
factor for the
Endurance race because we will have to brake hard and often going through, around the
course as well as all on the corners we will have to turn on.

iv. The third reason disc brakes will be better for our application is that they are proven
to work better in wet situations. If the course is anything like past years there will be a
lot of mud and a lot of water.
Disc brakes will fling the water and mud (if wet enough) off of itself and continue to give us
good braking force. The final reason is the weight and complexity factor. Disc brake systems
are much simpler and weigh less overall which is a big factor when the power of the motor is
set and cannot be modified.
4. For our calliper choice we are using wilwood ps1 callipers with piston area 0.99in2
and of bore size 1.12in. They are single cylinder, light weight and suit our application
perfectly. 5. The calliper pad area is a total of 1321.56mm2 and there are 2 pads. We
have assumed our friction coefficient between the disc and the calliper pad to be 0.35.
6. The brake fluid we have planned to use is dot4 brake fluid. It is extremely effective
and highly recommended for race cars due to its low compressibility properties.
5.5 Analysis
Load applied: 500N
Fig 5.2: Max Heat Flux: 8.101E5 W/m²
5.6 Brake Calculations
1. Weight distributions on axles
Static axle load distribution – ϕ=mf/m=120/220=0.54
Mf - static rear axle load (kg) =120
M – Total vehicle mass (kg) = 220
Φ – Static axle load distribution
Relative centre of gravity height – x=h/wb=0.233m
H – Vertical distance of cg from ground (m) = 0.420 m
Wb – wheel base (m) = 1.8m

2. To find stopping distance
Stopping distance=v2
/2*µ*g
=8.33^2/2*0.8*9.81 =4.4m
3. To find deceleration
V2
=u2
+2*a*s
(8.33)^2=(0^2)+(2*a*4.4)
a=7.88m/s2
4. To find stopping time
V=u+a*t
8.33=0+7.88*t
t=1.05 seconds
5. Braking force
Maximum brake force can be defined as the force experienced by the vehicle when the
vehicle comes to a halt
F=1/2(mv^2)
F=1/2(220*30^2) = 7.63KN
6. Braking torque
The torque induced on the wheels in order to lock them is known as the brake torque.
T=braking force*radius of wheel
=7.63*0.18= 1373.4Nm

CHAPTER 6
ELECTRICAL AND ELECTRONICS
6.1 Transmission:
Brushless DC Gearless Motors: They are also known as electronically commutated motors.
The controller provided along with the motor provides pulses of current to the motor
windings that control the speed and torque of the motor.
The advantages of a brushless motor over brushes motors include high power to weight ratio,
high speed and electronic control. They are found in computer peripherals, hand-held power
tools and vehicles.
The wheel hub motor is the brushless DC gearless motor incorporated into the hub of the rear
wheels.
Fig 6.1: Wheel Hub Motor
6.1.1 ISVC Rule Book Specifications:
1. Battery to be of nominal 48V or maximum of 60V.
2. Maximum number of motors allowed is 2 and should be BLDC or PMDC or hub motors. It
can be either geared or non-geared.
3. Maximum wattage rating including both motors is 2000W. Power source for the motor are
solar panels and battery.
4. Maximum current rating of battery permitted is 60A.
6.1.2 Motor Specifications:
Position: Rear
Rated Voltage: 48V
Rated Power: 1000W
No load Speed: 400-500 rpm

Rated Speed: 600 rpm
Rated Torque: 15N.m
Brake: Disc brake
Maximum speed which can be achieved: 45-60km/hr
Constant current at ideal load: 25 Ampere
Tire Width: 83mm
Length of motor cable: 50 cm
Rated efficiency: >85%
6.2 Solar Panels:
Monocrystalline PV cells have been the go-to choice for many years. They are among the
oldest, most efficient ways to produce electricity from the sun. This type of solar cells is
unique in their use of a single, very pure crystal of silicon. Using a process, similar to making
semi-conductors, silicon dioxide of quartzite gravel or crushed quartz is placed in an electric
arc furnace.
The major advantages of monocrystalline PV cells are longevity, efficiency, low installation
cost, greater heat resistance, and bankability.
Each panel was made by individually procured solar cells. Tabbing wire made of tin coated
with solder was used to connect the solar cells together to make 28 panels of 3x2 and 3x1
sizes. To clean the solar cell surface, isopropyl alcohol was used. After the cleaning process,
acid flux was dabbed before soldering.
Fig 6.2: Solar Panels
6.2.1 ISVC Rule Book Specifications:
1. Any kind of solar panels can be used. Fabrication of solar panels is allowed.
2. No solar panel should exceed the bumper of the vehicle.
3. Solar design and specification must be presented during technical inspection.

6.2.2 Solar Panel Specifications:
Type: Monocrystalline Silicon
Total number of cells: 144
Dimensions: 156 x 156 mm
Voltage per 3x2 panel: 3.28V
Voltage per 3x1 panel: 1.67V
6.3 Electrical:
The solar panel are mounted on the body of the vehicle and is connected in series and a
nominal voltage is obtained. The solar panels are further connected to the MPPT which is a
DC-DC converter that extracts maximum available power from the solar cells. It is a
technique commonly used in the case of wind turbines and photovoltaic solar systems to
maximize power extraction. The MPPT also ensures that the load receives optimum current
to be used.
The MPPT is connected to the battery via the BMS (Battery Management System). The BMS
has a discharge and charge MOSFET. Since Lithium Ion batteries get damaged when they are
subjected to overcharge, the BMS provides protection against overcharging. The BMS also
has the ability to manage energy and suggest how long the battery is going to last depending
on the rate of consumption.
The BLDC (Brush-Less Direct Current) motors are powered up through the motor
controllers. The motors are connected to the battery via the MPPT.
6.3.1 ISVC Rulebook Specifications:
1. Battery capacity should not exceed 100Ah and 48V.
2. Secondary battery voltage to not exceed 5V and 10Ah.
3. Proper insulation and covering is to be provided for the battery.
6.3.2 Battery Specifications:
Type: Lithium-Ion
Maximum voltage: 48V
Current discharge rate: 50Ah
Battery dimensions: 7 x 24.5 x 36.5 cm
6.3.3 Motor Controller Specifications:
Number of controllers: 2
Rated voltage: 48V
Rated power: 1000W

Fig 6.3: Controller and MPPT
6.4 Electronic Differential
There is a high complexity and bulkiness associated the commonly used mechanical
differential system for the rear shaft. This system while suited to heavier vehicles only adds
unnecessary costs and weight to the electric/solar electric vehicle. This is the reason why
KyRa uses an electronic differential system which dynamically detects the steering angle
input during a turn and uses empirical equations to determine the optimal speed difference
between the rear wheels to take a skid free turn. This system uses an Arduino microcontroller
running out in house developed algorithm to send signals to the motor controller which then
instantaneously changes the speed of the rear hub motors enabling the vehicle to safely
traverse very sharp turns without any mishaps.
6.5 Safety precautions taken to avoid electrical /electronic failures
There are a number of safety subsystems in the vehicle to prevent any component failures.
They are:
1) Fuses:
A must has in any circuit with sensitive components and high-power ratings, KyRa’s
electrical systems are provided with multiple fuses at strategic high current pathways to break
the circuit in case of a short circuit or excessive/unsafe current draw. Components protected
by fuses include the motor controllers, main power lines and the microcontroller.
2) Kill switches:
In case of serious emergency scenarios where there is an immediate necessity to cut the main
power circuit to avoid danger, kill switches are an integral part of the safety subsystem. There
are two kill switches mounted on the vehicle, one on the driver’s dashboard and the other is
on the right side of the body of the vehicle in case the driver is unable to kill the circuit on his
own facilitating the need for an urgent emergency stop by a person on the outside.

CHAPTER 7
DESIGN FAILURE MODE AND EFFECT ALALYSIS

7.1 DESIGN VALIDATION PROCEDURE

CHAPTER 8
DESIGN SAFETY AND PRECAUTIONS
• A car must have a strong structure to absorb crash energy while keeping the driver’s
compartment intact.
• Seat safety refers to the ability to prevent vehicle accidents effectively and to reduce
the damage of occupant to a minimum at the time of the accident.
• The components of seat are usually constructed from foam to provide comfort to the
rider. When choosing this product, foam manufacturers must consider the most
suitable foam for balancing comfort, support, safety, and recycling properties.
• Foam properties
Density 35 to 55 kg/m3
Tensile strength 145 KPa
Elongation at break 140 %
Tear Strength 200 to 300 N/m
• Tracks of the seat are welded and bolted to the floor.
• Fabricated new tracks, featuring - Vertical risers, to provide clearance for the power
seat equipment under the driver’s seat.
• Spacers, to maintain the correct height/angle, with a square or triangular cross-section
for strength.
• Seat belt.
• Fuses to protect the wiring and sensitive electronics from power surges.
• Two kill switches one on the inside and the other on the right side of the vehicle body
placed for switching the circuits off externally.
• The battery is well packaged inside a housing to avoid damage due to shocks.
• There are two fire extinguishers in the vehicle in case of fire arising due to short
circuits or battery damage.

CHAPTER 9
CONCLUSION
With emerging technological advancements in the use of renewable energy resources, team
Horus has designed and developed KyRa. Solar energy is available and cheap in the natural
resources where technology plays important and significant roles to use the tools of solar
energy. The Solar cars will be in need to support solar panels and the different instruments
for mechanical and technical design. The project is considered a challenge point that will use
the advantages of awareness which will have sustainable industrial methods in the field of
alternative energy. The car was designed in every aspect to the guidelines dictated in the rule
book. Every component has been tested analysed based on vehicle dynamics and knowledge
on mechanics. The team has used innovative technologies to improve its advancement in the
field of aerodynamics and electronics in the automotive industry, the team has innovated the
electronic differential which is the first of its kind in this field of solar vehicle racing and has
incorporated all the innovations mentioned. The team has thrived to develop technology and
hopes to continue to implement it in the future and succeed in the dynamic event.
REFERENCES
1) Google Scholar
2) NMIT Library
3) Hub motor: https://gogoa1.com/products/48v-800watt-motor
4) MPPT:
https://www.amazon.in/gp/aw/d/B01GV2UORY/ref=mp_s_a_1_2?ie=UTF8&qid=15
10763982&sr=8-
2&pi=AC_SX118_SY170_FMwebp_QL65&keywords=48v+mppt&dpPl=1&dpID=5
19do8z%2BQhL&ref=plSrch
5) Motor controller: https://robokits.co.in/e-bike/e-bike-motor-controller/motor-electric-
speed-controller-box-48v-800w-for-e-bike-scooter?cPath=235&
6) Software used: ANSYS Workbench 15, CATIA V5 R20
7) www.wikipedia.com, www.google.co.in
8) Reference journals and articles

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