Design Report for the Trike in EFFICYLE 2013 SAE India

8/10/2019 Design Report for the Trike in EFFICYLE 2013 SAE India

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EFFICYCLE SAE INDIA 2013

Design Report

PHOENIX

Rajiv Gandhi Instituteof Technology,

Kottayam

KERALA

South-2 Zone


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PHOENIX

E-COZI


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3

eam structure

FACUTY ADVISOR

Mr. Antony JK

TEAM CAPTAIN

Zahir Ummer Zaid

VICE CAPTAIN

Kevin Sebastian

Thoompunkal

STEERING

Jithu KS

Kiran Kumar C

Anuvind SurendranDESIGNING AND

TESTING TEAM

Zahir Ummer Zaid

Anwar Naseef

BRAKE

SYSTEM

Jithu KS

Jeeva Mathew

POWER TRAIN

Zahir Ummer Zaid

Anuvind Surendran

SUSPENSION

Mareena Antony

Kevin Sebastian Thoompunkal

Vinu Krishna

ELECTRICALArun Mohan

Mareena Antony


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Introduction

PHOENIX E-COZI is a recumbent tadpole trike with side-by-side

seating which incorporates modern technology so as to make it

passenger friendly . The complete designing process was based on

the theme of Safety and Comfort. Tadpole design is preferred to

delta design since tadpole has advantages of better driver safety,

dimensional stability, aerodynamics and ergonomics. An innovative

Kinetic Energy Recovery System (KERS) has also been incorporated

for better performance and easiness. With strong chassis designed

to withstand impacts and covering to protect the rider from debris,

wind current and rain, PHOENIX E-COZI makes sure that no

where it compromises safety and comfort.

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Design Methodology

The vehicular design and the subsystem designs are performed after

profound research into the particular field. The subsystems are separately designed, validated and accepted after

rigorous comparisons and market analysis.

The components to be procured such as the differential, electric motor

drive system, electronic components like sensors and switches are selected

based on the market availability. The companies have been contacted to

know the feasibility of availing us with the components, the following are

the companies which had provided us with the specifications regarding the

components:

1.) Samagaga Industries, Taiwan (DIFFERENTIAL)

2.) Falbrook Technologies, USA (NUVINCI HUB)

3.) Tachometric Controls, India (BLDC MOTOR,DRIVE SYSTEM and

EPICYCLIC GEARS)

4.) Keltron Ltd. (ELECTRONIC COMPONENTS)

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The Gantt chart was prepared to aid us in arriving at ourfinal vehicle design and specifications.

The duration for the event was speculated from 11th

February to 8th June, allocating considerations for the

academics and activities

Our design methodology of designing the chassis with

reference to the requirements of the subsystems like

steering , suspension etc. was adhered while preparing the

plan

Project Plan

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Gantt Chart for Project Plan


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Gantt Chart for the Vehicular Design

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Chassis

Designed with priority for Safety and Comfort

Vehicle configuration:Recumbent Tadpole design

Thedesign is justified

for the following reason:

1. Recumbent seating position is more ergonomic than the upright position.

2. Recumbent design aids in obtaining a low center of gravity, which in turn increase the

stability of the vehicle.

3. The tadpole design has reduced chances of toppling when executing turns.

Technical Specifications

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Geometric views of the completed chassis

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The Chassis design imparts the following specification for the vehicle:

Wheelbase: 1650 mm

Track: 1200 mm

Chassis Exoskeleton figures

Chassis Exoskeleton is fabricated from Nominal Pipe Size NPS) 1 Schedule 5

pipe,with the following specs:

O.D= 48.26 mm , thickness= 1.65 mm


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The strengthening members are fabricated from NPS 1 Schedule 5,with the

following specs: O.D = 26.67 mm , thickness = 1.65 mm

The utility box of the prescribed dimensions is position in the front of the vehicle to

balance the load distribution

A metal sheet will be provided on the underbelly of the vehicle for the safety and

comfort of the passengers, which helps in developing a neat floor space 12


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Analysis of the Chassis

1.) Deformation analysis under an frontal impact load of 2000N


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2.) Equivalent stress under the frontal impact load of 2000N

The stress value is within the limits of the tensile strength of SS 202.


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Power Transmission

For better ease in motoring, an all-wheel drive system is implemented in the vehicle

The drive-train layout is as illustrated below:

For the ease of interpretation, the drive-train layout has categorized into two:

1.) Pedal Drive-train 2.) Motor Drive-train

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The calculated pitches of the chains are compared with ISO 2403-1991 standards of

chains.

Chain 1- 06 B (pitch=9.525 mm)

Chain 2- 12 B (pitch=19.05 mm)

Chain Drive Design Procedure Chain 1 )

Step 1- Approximating the velocity ratio of the sprockets as 2

/ = 2 /= 2

Step 2- From the reference table( table 21.5, bibliography: A Textbook of Machine

Design by J.K. Gupta) ,which tabulates the minimum number of teeth against velocity

ratio,No. of teeth in the driven sprocket(Sprocket 2)= 27

Step 3- From the approximated velocity ratio,

= 227 54

Step 4-

Designed power = rated power service factor

The rated power to be calculated is obtained from the following graph , which was

plotted for an experiment concerning the electric power generated by using a pedaled-

dynamo performed by Pedal-Power Generators LLC

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the maximum power developed is estimated

at 175W.

The service factor( ) is given as follows

= 1

where,

1=load factor( 1.25,for variable load )

=lubricating factor( 1.5,for periodic lubrication )

=rating factor( 1,for operations up to 8 hours per day )

Here, =1.875

Designed power 175 1.875 = 328.125W

Step 5- Power rating-vs-rotational speed of driven sprocket is used to obtain the

rotational speed of the driven sprocket, which is interpolated at 150 r.p.m

pitch line velocity of driven sprocket()= DN /60

where, D= pitch diameter of sprocket and N= rotational speed

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Pitch Diameter is given by the following equation

D= (pitch)cosec(180/no.of teeth)

= 82.04 mm

= 163.815 mm

Considering the market availability of these sprocket the following specifications are

fixed

= 80 mm and =160 mm

3.1482.014150/60 = 0.64 m/s

Calculating the length( L ) of chain required

L(no. of chain links)(pitch of the chain) = K p

The center-to-center distance( x ) is given by the following equation

=

4 ( ( 1 /2) (

+

8((1)/2))]

Solving the above equation for the value of K , as the values of x, p ,1 and are known.

Chain 1- K= 139.804~140

Length of Chain 1 = 1.33m


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Chain 2- K=124.9 ~ 125

Length of Chain 2 = 2.37 m

Layout Diagram of the Chain Drive

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Electric-motor drive

A 400W BLDC motor is used to power the front wheels via a differential unit.

The BLDC and PMDC motors were compared

Based on the above criteria Brush Less DC (BLDC) Motor was selected.

Analyzing our requirements of providing 400W and motoring the estimated 350 kgvehicle( fully loaded with two passenger each weighing 115 kg), the motor with thefollowing performance curve was selected

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BLDC MOTOR PMDC MOTOR

Higher speed range Low speed range

(due to limitations imposed by the brushes)

Power loss at brushes can be avoided Power loss at brushes

High Output Power and Efficiency Moderate values

Maintain or increase torque at various speeds As speed increases torque decreases

(due to increased brush friction)

Longer life ShorterCompact size and low noise operation Electromagnetic Interference (EMI) is generated

by brush arcing

Low rotor inertia

Improves dynamic response

Higher rotor inertia which limits dynamic

characteristics

Less or sometimes no maintenance required

(due to absence of brushes)

Periodic maintenance required

(brush cleaning and replacement is essential)

Higher cost of construction

(Total cost becomes comparable)

Lower construction cost

Maintenance cost is higher


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Operating power of the Battery-pack:

Pack rating- 48V,35Ahr

Motor rating- 400W

Current drawn by the motorMotor rating/ Battery voltage = 400W / 48V

= 8.333 A

Theoretical Runtime Battery Ampere-hour rating / motor current = 35 Ahr/ 8.333 A

= 4.2 hours

At 40 % loss,

Actual runtime 4.2 - (4.2(40/100)) = 2.52 hours

Differential unit is employed with two universal joints on each half-axle tocompensate for the independent suspension and steering system of the front wheels

Contrary to the figure shown above the differential unit would have a direct drive

from the motor in order reduce the complexities of a derailleur gear system.


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The layout of the front-wheel power system is as illustrated

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Given layout has ergonomic advantages as the torso rests on a section which is

inclined at an angle of 30 degs with the vertical and the thigh rests on the section

which is inclined at 6 degs with the horizontal

The H-point is determined at 661.954 mm above ground, which is within the limit

prescribed in the rulebook.

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The seat is mounted on to the chassis by suitably placing it on the cross members

and exoskeleton of the chassis

As per the rulebook instruction, 3-point seat belts are provided in the seating

arrangement.

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Steering System Based on the fact that by implementing the steering system on the front wheels,

the tractive force available for steering( cornering traction ) is increased when

compared to a single steerable-wheel(rear-wheel steering),the vehicle is designed

front wheel steering system based in Ackermann geometry. The Steering system is designed to achieve 100% Ackermann geometry, with the

specifications as shown in the figure

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Handle bars will be used as the steering ratio is 1:1

Adhering to the rulebook, the steering system has been designed to possess a minimum turning

radius of 3.9 m in the outer wheel

The steering mechanism employed is the Articulated Steering Mechanism, which

is illustrated in the following figure


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U-joints will be employed to position the steering shaft at a convenient

position, considering the accessibility of the driver

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Allowances had been provided in the chassis exoskeleton to facilitate the steering

angle of upto 35 deg

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B ki t


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Braking system Mechanically actuated disc brakes are provided on all wheels

As 26 MTB tires are used, the commonly available 160mm disc are used

Using a split-cable system, the front-wheels brakes will lock at the same instant, thus

eliminating any of the side-wise erratic movements during braking.Brake Calculation

Stopping Distance(s)=/2 m

where = velocity (m/s)

= coefficient of friction between the tyre and the road

g= acceleration due to gravity(m/s^2)

CASE 1: under top-speed condition (= 40 kph)

normal condition( = 0.8), s=7.9 m

extreme condition(= 0.3), s= 20.9 m

CASE 2: Brake-test Conditions = 2 /

Considering the 5m available for bringing the vehicle to

a complete halt,

=0 m/s , = 5 m

u = 50m/ 15 seconds

= 3.33 m/s 37

Acceleration (d) during the braking of the vehicle= -1.10 /


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( ) g g /Acceleration in g-units(D) | d |/g = 0.112g

Braking force required( ) = mass of the vehicle*deceleration N= 3501.10 = 384.5 N

Braking Torque( )=

N.m

where is the static laden radius of the tire andis the ratio of the radius of the brakedisc to the static laden radius of the wheel.

here,

= 0.3302 m and = 0.08 m / 0.3302 m 0.242 = 524.6 Nm

Friction force()= mass of the vehicle= 622.22

Real-life deceleration & Stopping distance

The deceleration used in calculations is a steady state one called MFDD (mean fullydeveloped deceleration). It assumes the vehicle is either braking or not. In practice it

takes a time for the system pressure to rise and the friction to build up. This is not thedriver reaction time but the system reaction time. Where a calculation requires astopping distance or an average stop deceleration then this delay must be taken intoaccount. For calculations a linear build up over 0.6 second is used i.e 0.3 second delay.

=/(/ 0.3)where is the average deceleration for the whole stop( in g-units ), is the test

speed(m/s), is the deceleration(MFDD)(in g-units) 38

Here under given conditions,


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Here under given conditions,

= 0.177 g -1.15 m/s

Stopping distance (s) = /(2 )= 4.8 m ( which is within the limit prescribed in the rulebook)

Weight Transfer during braking()

=

where, is the weight of the vehicle, is the coefficient of friction, is the height ofthe center of gravity and is the wheelbase.

for the vehicle, = 114 kg

Suspension system


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Suspension system with passenger comfort as the top priority, the vehicle features the following

suspension systems

front wheels- Double Wishbone suspension

rear wheel- Double-sided Swing-arm suspension

The reasons for providing the suspension systems are:

1.) Passenger comfort

2.) Roll stability in execution of turns and thus the safety of the passengers

3.) Reduce the undesirable shocks on the vehicular frame, thus increasing its

reliability and durability

Front Suspension

- features the following illustrated geometry

- unequal wishbones in non-parallel arrangement

- geometry is designed to have the lowest possible distance between the roll-centre

and the CoG, thereby reducing the roll-angle of the vehicle when under the action

cornering forces

In the suspension geometry, the distance between the roll-center and CoG is 0.38 m

i.e, the roll-force creates a torque with an arm of radius 0.38 m.

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The geometry provides neutral camber, which was validated given the 1.95 width ofthe tire and also the increased rate of wear and tear if camber angle was non-

neutral.

The Kingpin inclination of 3.938 deg. is provided to produce a scrub radius of

0.07m,which helps in achieving appreciable self-centering ability of the steering

linkages and the directional stability of the vehicle

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the upright is designed so as to facilitate a caster angle of 3 degs ,further increasingthe returnability of the steering system

. The wishbones are fabricated from NPS 1 schedule 5 pipes

The coilover-springs of the suspension system will be attached to the upper

wishbone, rather than attaching it in the lower wishbone with an offset from the

center; the reason been that itll be compromise the efficient operation of the system

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Wishbones and uprights are fabricated in the below illustrated geometries


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p g g

The Upright is manufactured from 0.01m thick steel plates and the geometry is

fabricated by welding. The wishbone attachments are positioned to facilitate the 3.98 deg. Kingpin

inclination.

The coil-over springs are selected on the basis market availability and vehicle

requirement.

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Analysis of the Upright under a vertical bump-force of 4g(considering a

static loading of 500N)

1.) Deformation

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2.) Equivalent Stress


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Rear Suspension System


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Rear Suspension System

-a double-sided swingarm with a monoshock suspension is employed for the rear

suspension

-the monoshock coil-over spring provides exceptional ride quality

-the coil-over unit is attached to the swingarm at a distance calculated by considering

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the motion ratio and the deflection of the spring at different attachment points.


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p g p

- the coil-over spring for the rear suspension is that of Honda Unicorn with spring

travel of 3 inch.

Tire Specifications

Based on the market survey, cost analysis and reliability, the 26 MTB tire with

1.95 tread are used in the vehicle

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Double-sided Swing-arm


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Ergonomic Features


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Ergonomic Features

The recumbent design facilitates a very comfortable riding position with

zero-strain developed by the body in supporting itself.

The pedaling position is carefully determined to extract maximum power

with minimum exhaustion for the passenger

The innovative and simple rear gear system( NuVinci CVT ) relieves the

driver from the complexities of the derailleur gear system.

As the electric motor is directly connected with the differential, the motor

operation doesnt require any gear selection, but just the press on thethrottler.

The chassis design provides a good line-of-sight for the occupants.

The metal-sheet floor and the front fairing augments the comfort of the

passengers.

The KERS used in the vehicle aids in reducing the effort applied by thedriver on the brake lever, as the reversal of the motoring action itself helps

in decelerating the vehicle.

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INNOVATIONS


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INNOVATIONS

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An innovative Kinetic Energy Recovery System is employed, which utilizes the4th quadrant operation of the BLDC motor.

-apart from the BLDC motor, its controller drive and the battery, the other main

components involved are:

Power conditioner

Change-over switch

Brake lever position sensor and twist-throttler sensor

Power-conditioner: is a high gain amplifier, which instantly multiplies the voltage

induced by the motor operating with 4th quadrant characteristics. Its operation iscontrolled by signals from the brake-lever sensor and twist-throttler sensor.

Change-over switch: is an electronic switching device which operates in

accordance with the signal from the brake-lever sensor.

Brake-lever position sensor and twist-throttle sensor: are highly sensitive

electromagnetic-position sensors with reed switches and magnets.

WorkingUnder normal motoring conditions, the device connects the terminal of the BLDC

controller unit with the terminal of the BLDC motor. When braking or

decelerating, the brake-lever sensor/twist throttle sensor sends signal to the

switching device, which cuts the supply of battery voltage to the BLDC motor.


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The BLDC motor would be operating in the 4th quadrant due to the

braking / deceleration, the voltage so induced is directed to the

power conditioner, which in turn charges the battery. Thusharnessing the energy dissipated during braking and deceleration,

constituting the KERS.

Fabrication Plan


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Fabrication Plan The Gantt chart was prepared for the fabrication of the vehicle, considering the

market availability of the components and the duration for synchronizing the

different systems.

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Tasks Start Date Duration (Days) End Date

Virtual Round 7/13/2013

Speculative date for announcing virtual round result 7/31/2013

Raw material procurement 8/1/2013 7 8/7/2013

Construction of the chassis exoskeleton 8/8/2013 15 8/22/2013

Fabrication of the suspension linkages 8/23/2013 7 8/29/2013

Fabrication of the steering linkages 8/23/2013 7 8/29/2013

Fixing suspension 8/30/2013 3 9/2/2013

Fixing steering 9/3/2013 4 9/6/2013

Fixing of strengthening members 9/7/2013 4 9/10/2013

Seats and pedals fixture 9/11/2013 4 9/14/2013

Power train set up 9/15/2013 7 9/21/2013

Miscellaneous electrical works 9/22/2013 4 9/25/2013

Fairing and sheet metal works 9/26/2013 3 9/28/2013

Tyre 9/29/2013 4 10/2/2013

Road Test 10/3/2013 7 10/9/2013

Speculative date for main event 10/16/2013


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Gantt Chart for Vehicle Fabrication

College Facilities


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College Facilities

The mechanical engineering lab at our institute houses a well equipped CAD lab and

all fabrication departments like fitting, welding ,lathe-machining workshops.

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Design Validation PLAN


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Design Validation PLAN

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PROCEDURE NO DESCRIPTION ACCEPTANCE CRITERIA RESPONSIBILITY TEST SOURCE

1 Dimensional Analysis and TolerancesStrict Adherence with the

Engineering Drawings Kevin SebastianProtyping and CAD

modelling

2 Chassis Fabrication Efficient utilisation of raw materials Anuvind Surendran Engineering Drawing

3 Steering System

Ackermann Geometry and specified

mechanism is satisfied Anwar Naseef Software Analysis

4 Suspension SystemPermissible suspension travel is

maintained Kiran Kumar CSoftware Analysis and

UTM machines

5 Powertrain

Proper positioning of sprockets and

chains Zahir Ummer Zaid

Theoretical Analysis

and Protyping

6 Brakes Perfectly timed locking Jeeva Mathew Visual Inspection

7 Tires

Balancing alignment and inflation

rates Mareena Antony Visual Inspection

8 Safety

Proper Installation of bumper,

Fairing Vinu Chandra Visual Inspection

9 Electrical and Electronics Proper Mounting Arun Mohan Prototype

10 Development of KERS Proper Design Jithu K S

Circuit and sample

testing


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COST REPORT

STRUCTURAL

MATERIALS

ELECTRICAL

EQUIPMENTS

POWER TRANSMISSION

EQUIPMENTS

OTHER EQUIPMENTS


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COST REPORT

STRUCTURAL MATERIALS 5000.00

ELECTRICAL EQUIPMENTS 21000.00

POWER TRANSMISSION 45890.00

OTHER EQUIPMENTS 5480.00

TOTAL ESTIMATED COST 77370.00/-


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Potential Markets and


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Potential Markets and

Customers

Large institutions with huge campus area

i) Industries

ii) Educational Institutions

Small scale entrepreneurs

i) It can be used for short distance journeys (with no carbonemission) in towns and cities for delivery purposes without

burning out any fuel in traffic curbs.ii) Carrying goods at low cost thus maximizing profit.

iii) Can replace existing non stable rickshaws with much more stableand safer tri-cycles.

Tourism Department

i) Two men boat riding can be replicated with the PHOENIXE-COZI

ii) Scenic tour in Natural Parks and Sanctuaries without pollutingthe environment.

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Concepts Contribution And


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Concepts ,Contribution And

Why go for Phoenix ECozi

Zero Emission.

High efficiency.

Increased safety , stability, and speed control than ordinarycycle.

Cheaper alternative to scooter for short trips.

Use of recyclable materials and hence eco- friendly.

Increases the battery life with the use of various electrical

systems like the regenerative braking system. Power surge using Kinetic Energy Recovery System (KERS).

Aerodynamic design with ergonomically designed seats.

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Variants


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Variants

Single seated models.

High torque motor models can be added for high inclination

conditions.

Variation in the electrical charging model.

Amphibian version of the vehicle

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Design Report for the Trike in EFFICYLE 2013 SAE India

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