project – black widow – · web viewhonda dio engine ( finalized decision)28 fuel injected...
TRANSCRIPT
Table of Contents
List of Figures.........................................................................................................................................5
List of Tables..........................................................................................................................................6
1.Executive Summary............................................................................................................................7
2. Design Requirements.........................................................................................................................8
3. Project Management.......................................................................................................................10
3.1 Project Overview.......................................................................................................................10
Project Authorization:..................................................................................................................10
Project Manager Authorization:..................................................................................................10
Key Stakeholders:........................................................................................................................10
Project Goal(s):............................................................................................................................11
Project Priorities matrix:..............................................................................................................11
Scope Statement:........................................................................................................................11
Project Requirements:.................................................................................................................11
Project Constraints & Boundaries:...............................................................................................11
Initial Project Risks:......................................................................................................................11
List of Deliverables.......................................................................................................................12
Task allocation.............................................................................................................................12
Cost Estimates:............................................................................................................................13
Schedule Estimates:.....................................................................................................................13
Success Criteria:...........................................................................................................................13
3.2 Organization of work and timeline............................................................................................14
3.3 Responsibility Matrix.................................................................................................................14
4. Design Selection Process.................................................................................................................15
4.1 Chassis.......................................................................................................................................15
4.1.1 Backbone............................................................................................................................15
4.1.2 Monocoque........................................................................................................................16
4.1.3 Tubular Space Frame – selected design..............................................................................17
Chassis Dimensions......................................................................................................................18
.....................................................................................................................................................18
.....................................................................................................................................................19
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...............................19
4.2 Body Frame................................................................................................................................20
4.3 Engine........................................................................................................................................27
4.3.1 Hatz-Diesel 1B20.................................................................................................................27
4.3.2 Yanmar L48N.......................................................................................................................28
4.3.3 Honda GXH 35 & GXH 50........................................................................................................28
Honda Dio Engine ( Finalized Decision)............................................................................................28
Fuel injected system & Electronic Closed Loop Engine Management (ectrons fuel injected )............29
4.4 Drive Mechanism.......................................................................................................................29
4.4.1 Flat Belt Drive.....................................................................................................................29
4.4.2 Roller Chain – selected........................................................................................................30
4.4.3 VBelt / Conical Pulleys Drive – (Finalized Decision)................................................................30
Steering system ( Compact Rack & Pinion with tie rods) ( Finalized Decision).................................31
Specification................................................................................................................................32
Design Alternatives......................................................................................................................32
Design Evaluation........................................................................................................................33
Assembly.....................................................................................................................................33
Components................................................................................................................................35
4.5 Clutch.........................................................................................................................................36
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4.5.1 CRS Clutch-rotor – selected................................................................................................36
4.5.2 Cone Clutch.........................................................................................................................36
4.5.3 Plate Clutch.........................................................................................................................37
4.5.4 Centrifugal Clutch...............................................................................................................38
4.6 Transmission..............................................................................................................................39
4.6.1 Continuously variable transmission....................................................................................39
4.6.2 Sprocket and Derailleur Transmission................................................................................39
4.7 Brake......................................................................................................................................40
4.7. 1 Hydraulic Rim Brakes.........................................................................................................40
4.7.2 Roller Cam Brakes...............................................................................................................40
4.7.3 Hydraulic Disc Brakes – selected.........................................................................................41
4.8 Auxiliary.....................................................................................................................................44
Electrical components and wiring....................................................................................................44
4.9 Final Design........................................................................................................................45
5. Engineering Design Process.............................................................................................................46
5.1 Engine Modification and Mounting...........................................................................................46
5.2 Fuel System................................................................................................................................46
Conclusion...........................................................................................................................................47
References...........................................................................................................................................48
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List of Figures
Figure 1 Schedule Estimation..............................................................................................................13
Figure 2 Backbone Chassis (Harlo, 2009).............................................................................................15
Figure 3 Monocoque Chassis (Petrol Smell, 2010)...............................................................................17
Figure 4 Tubular Space Frame (sharma, 2012)....................................................................................18
Figure 5 Side View...............................................................................................................................19
Figure 6 Top View................................................................................................................................20
Figure 7 Front view..............................................................................................................................20
Figure 8 Isometric View.......................................................................................................................19
Figure 9 Frame with lofting..................................................................................................................21
Figure 10 Side view..............................................................................................................................22
Figure 11 Top View..................................................................................Error! Bookmark not defined.
Figure 12 Skeleton View......................................................................................................................23
Figure 13 Side view..............................................................................................................................24
Figure 14 Front View...........................................................................................................................25
Figure 15 Front View with complete body...........................................................................................26
Figure 16 Back View.............................................................................................................................27
Figure 17 Back view with skeleton.......................................................................................................28
Figure 18 Hatz Dieself 1B20 (HATZ Diesel, 2013).................................................................................28
Figure 19 Yanmar L48N (yanmar industries, 2013)..............................................................................29
Figure 20 Lombardini 4 cylinder engine (ebooksbrowse, 2011)..........................................................30
Figure 22 Series 15 LD curves..............................................................................................................30
Figure 23 Flat Belt Drive (Bedroom Workshop, 2013).........................................................................31
Figure 24 Roller chain (Mechanical Power, 2013)...............................................................................32
Figure 25 Rack and pinion components...............................................................................................34
Figure 26 Rack and Pinion dimensions................................................................................................35
Figure 27 Rack and Pinion Assembly...................................................................................................36
Figure 28 CRC Cluctch Roto.................................................................................................................38
Figure 29 Cone Clutch (CUCDC.com, 2006).........................................................................................38
Figure 30 Plate Clutch..........................................................................................................................39
Figure 31 Centrifugal Clutch (Dan's Motorcycle Repair Workshop, 2013)...........................................40
Figure 32 Rohloff Speedhub (Wikipedia, 2009)...................................................................................41
Figure 33 Nuvinci Transmission (Drummond, 2009)............................................................................42
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Figure 34 Front (left) and Rear (right) Derailleur Transmission (Wikipedia, 2012)..............................43
Figure 35 Hydraulic Rim Brakes (Togoparts.com, 2013)......................................................................44
Figure 36 Roller Cam Brakes (Bike Stash, 2013)...................................................................................44
Figure 37 Hydraulic Disc Brake (Performance Bicycles, 2013).............................................................45
Figure 38 Hydraulic Disc Brake System................................................................................................46
Figure 39 Final Design Flowchart.........................................................................................................50
Figure 40t Fuel System........................................................................................................................52
List of Tables
Table 1 Priorities..................................................................................................................................11
Table 2 Cost Estimation.......................................................................................................................13
Table 3 Torque Table...........................................................................Error! Bookmark not defined.15
Table 4 Rolling Resistance Coefficient.................................................Error! Bookmark not defined.20
Table 5 Steering Design Evaluation......................................................................................................35
Table 6 Steering System Components.................................................................................................37
Table 7 brake specification..................................................................................................................46
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1.Executive Summary
HCT-Sharjah’s final year’s mechanical engineering students team “THE EMIRATES FALCON”, will participate this year in Shell Eco Marathon “Energy Efficiency” race. The international race will take place in Manila, Philippines during 3rd – 6th March 2016. Over a fast track timeline of 4 months, the team 6 members and their faculty supervisor have worked relentlessly to complete the design and construction of an energy-efficient petrol fuel injected 3-wheeled prototype.
The annual competition challenges students to design, build and drive a vehicle that can travel the furthest distance on the least amount of fuel. In the three-days international competition “THE EMIRATES FALCON” will compete with 17 entries in the Prototype Internal Combustion Engine (ICE) Petrol category, based on measurement units of kilometer per liter of fuel. The HCT team is one of the only two UAE participants in the competition among 182 universities and colleges from Asia North Africa and Australia.
The HCT-SHJ team has the objectives of presenting a vehicle which features an innovative streamlined design blended with the UAE spirit and heritage. The prototype is powered by an efficient Honda engine which has a displacement of 50 cc fitted with a closed-loop electronic engine management system. The car has advanced steering controls and optimized driver ergonomics. To increase the efficiency, low drag ceramic bearing are used on all wheels. The car tires are low friction racing tires installed on robust wheel rims fitted with dual system ventilated brakes for safer braking.
With safety as a core objective in mind, the team made the car frame as a roll-cage constructed from light aluminum pipes with front and rear crumple zones. For increased safety, the driver is restrained using a 6 point quick release racing seat belt. The body is made from light-weight polycarbonate sheets. Without the driver, the “Emirates Falcon” prototype weighs about 80kg and can reach speeds of about 60km/h with expected fuel efficiency more than 350 km/ liter of petrol.
The team and their supervisor are grateful to the SHJ-HCT Director Dr. Muhadditha Al Hashimi, the engineering Program Chair Mr. Arif Al Karrani for their unlimited support and to ZADCO for sponsoring the team.
Engineering faculty Mr. Ayman Ramadan is proud to supervise this innovative HCT engineering team in this professionally rewarding international contest. He said: “The Shell Eco Marathon Race challenged our students to apply engineering knowledge and skills to achieve high transport energy efficiency aiming to sustaining our Nation’s petroleum reserves and mitigating the harmful environmental impacts. We are optimistic that our team will excel as a showcase of the HCT’s and the whole UAE’s strong commitment towards more efficient use of energy and scientific innovation”.
Student team leader; Ali Saeed Al Qaydi has expressed the heartbeat of the team. He said: ”We are keen to represent our great nation the UAE in this international event and we are optimistic that we will perform well in both scoring a high fuel efficiency result as well as to score high against the off-track awards of innovation, safety and communication skills awards which we registered for”.
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2. Design Requirements
The requirements were provided by the competition itself which included the following points:
1. The prototype should have three or four wheels which should be in contact with the road
under all running conditions
2. Aerodynamic appendages which change shape due to the wind pressure while the car is
moving are forbidden. This includes sharp protruding objects which can be harmful to the
other participating teams must have a radius of 5cm and should be made up of soft materials
like Styrofoam etc
3. No objects which can hurt the driver during the competition should be placed inside the
vehicle
4. Windows should be made of a material which doesn’t shatter or break such as any kind of
polycarbonate
5. All energy compartments should be easy to access for inspection
6. All objects must be securely mounted
7. The vehicles chassis must be solid in nature, equipped with an effective roll bar which
extends 5cm around the driver’s helmet while seated in the driving position with seat belts
fastened. Moreover, it should be long and wide enough protecting the driver from front or
lateral collisions
8. The vehicles propulsion and energy storage system must be separate in a permanent
bulkhead which is made to be of a fire retardant material and construction sealing the
driver’s compartment. If the prototype is open it should extend 5cm above the highest
length of either the propulsion and fuel system or the driver shoulders
9. The visibility of the driver should cover the complete front and 90 degrees longitudinal of
each side without the help of any optical or electronically devices such as prisms. Rear view
mirror having a minimum surface area of 25cm2 on each side of the vehicle is necessary
10. Safety belts must be built in having at least five mounting points placed below the driver’s
torso and attached firmly to the vehicles main structure with a single buckle system. The belt
should be worn at all times during the competition when in motion and should withstand a
force of at least 1.5 times the driver’s weight.
11. Vehicle should have a large opening to the cockpit for accessibility at all times including the
drivers position in such a way that he/she can be pulled out in the case of emergency. The
doors can be equipped with a folding, hinged or detachable mechanisms and to open it from
outside is marked clearly with a red arrow and doesn’t require any tools to do so. Use of
adhesive tapes to close the door is strictly forbidden
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12. Each vehicle should contain an electric horn built towards the front where it is easily heard
by other vehicles and marshals having a sound greater than 85dBA when measured 4m
horizontally from the vehicle. Moreover, the pitch should be equal or greater than 420Hz
and a noise capacitor/volume greater than 110dBA
13. Every vehicle must have an onboard fire extinguisher either ABC or BC type having a
minimum extinguisher capacity of 1 kg. the driver should know how to operate this and
should make sure it is full at all times and is valid by ensuring the date of expiry hasn’t
passed. Plumbed in extinguishers must be available in the engine compartment and should
be discharged there in times of emergency. Hand held extinguisher should be available in the
cockpit and easily accessible by the driver
14. Head first driving position is prohibited
15. All vehicles must include a clutch system and if is of centrifugal/automatic in nature, the
starter motor speed must always be below the engagement speed of the clutch. Manual
clutches should have an inoperable starter motor having an interlock facility to compensate
this. It is a must to install an effective transmission chain or belt guard
16. All the components in the exhaust system must be made of metal and should be installed in
such a way that all the gases should be released outside the vehicle. The pipes shouldn’t
extend further than the vehicles body and must comply with the environmental standards.
17. An emergency shutdown operable from inside and outside the vehicle must be installed in
the permanent section of the vehicle and should be clearly marked with a red arrow having a
length of 10cm and width of 3cm.
18. Dimension requirements are as follows:
a. Maximum height should be less than 100cm
b. The maximum height measured from the top of the driver’s compartment must be less
than 1.25 times the maximum track width between the two outermost wheels
c. The width of the track must be at least 50cm measured between the midpoints of where
the tyres touch the ground
d. Wheelbase must be at least 100cm
e. Maximum total vehicle width shouldn’t exceed 130cm
f. Maximum total length shouldn’t exceed 350cm
g. Maximum vehicle weight without the driver is 140kg
19. Front or rear wheel steering is permitted but if organizers are not satisfied by the
effectiveness the vehicle will be removed from the competition. Turning radius should be
enough to allow the driver to overtake other competitors, typically 6m.
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20. The vehicle must be equipped with two individual braking systems; single command control,
command transmission and activators where one will operate all front wheel activities and
the other will operate all rear wheel activities. These both can be activated at the same time
3. Project Management
3.1 Project Overview
Project Authorization:Approved By Job Title Signature Date
Dr. Shakib
Dr. Yu Chan
Project Manager Authorization:The Team Manager is Mr. Khalid Mohamed Al Ali and is responsible for the following:
1- Supervise and manage the overall performance of the dedicated tasks for the team Abu
Dhabi high Tech.
2- Analyzing, reporting, giving recommendations and developing strategies on how to improve
the quality of the product.
3- Achieve team Abu Dhabi high Tech objectives.
4- Working out recognition and rewards.
5- Responsible for the progress and development of the project (finances and earnings).
6- Identifying problems, creating choices and providing alternatives courses of actions.
Key Stakeholders:1- Dr Shakib Engineering department dean - Authorizing payment and following project phases
and taking the responsibility of contacting sponsors.
2- Dr Yw Chan Mechanical engineering tutor - The dedicated tutor responsible for the project
and controlling of phases and end quality.
3- Khalid Mohamed Al Ali is the Project Manager and an engine team member.
4- Ibrahim al Beshir and Mohamed Adel are team members responsible for the chasses frame
and Body.
5- Marwan Al Nuaimi and Ibrahim Al Beshir are team members who are responsible for the
Steering and break systems.
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6- Ahmed Saleh Al Harbi a team member who is responsible for the engine, clutch, and gear
selection.
7- Ali Al Amri is a team member responsible for the auxiliaries and other supporting systems.
Project Goal(s):
To design, build and test energy efficient vehicles. The car should go the furthest distance using the
least amount of energy.
Project Priorities matrix:Table 1 Priorities
Time Scope Cost
Constrain
Enhance
Accept
The priority of the project is that it should end on the 1 st of July with rapid changes to meet the dead
line and the dedicated cost limit.
Scope Statement:
Designing and building a fuel efficient car that will be used in the SEM Asia on the 3-7 of July
2012.The car has to be light and environmental friendly and should be built according to the SEM
organizers’ standards.
Project Requirements:1- Produce a three wheeled vehicle that travel maximum distance, while minimizing
fuel consumption.2- The car must be environmentally friendly.3- The project must meet the time deadline and the cost proposed.4- The vehicle must meet all SEM competition requirements.
Project Constraints & Boundaries:
1- Budget
2- Time constrains
3- SEM Rules
Initial Project Risks:
Not to meet the dead line or fail to achieve the project end with the dedicated budget.
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List of Deliverables
A three wheeler car that can travel the farthest using the least amount of fuel
Task allocation
Work Break down structure
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Car
Vehicle structure
Team
Mohamed
Ibrahime
Khalid
Task One
Chassie
Frame
body
Stering and Break system
Team
Marwan
Mohamed
Ali
Task Two
Stearing
Break
Wheels
Powerterine
Team
Ahmed
Marwan
Khalid
Task three
Engine
Gear
Clutch
Auxiliaries
Team
Ali
Ibrahime
Ahmed
Task four
EMU
comunication
Electrical
Cost Estimates:Table 2 Cost Estimation
Parts Cost NotesChasses frame and body AED 60,000.00
Engine and gear AED 20,000.00 Acquired from previous project
Clutch system AED 9,131.00Brake System AED 9,500.00 Acquired from
previous projectSteering System
Auxiliary and electrical system AED 11,000.00 Acquired from previous project
Air tickets AED 37,000.00Accommodation AED 30,000.00
Shipping AED 90,000.00Estimate increase 30% AED 80,000.00
Schedule Estimates:
Figure 1 Schedule Estimation
Success Criteria:
Ability to deliver promises with first time right
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3.2 Organization of work and timeline
Figure 2 Timeline Gantt chart
3.3 Responsibility Matrix
Table 3 Risponsibility matrix
Responsibility matrix for Echo marathon (black widow)
Khalid
Marwan Ahmed Ali Mohammad Ibrahim Chan
Engine calculation R S R CClutch calculation S S R S CElectrical and Auxiliary interface R S S Chaise design S R S Cbreak design S R S body design R S S Document control R S S Steering design S S R
R ResponsibleS SupportC Consultant
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4. Design Selection Process
4.1 Chassis
The internal framework of any vehicle is called the Chassis. It involves the wheels, frames and other
related equipments and acts as a shield against external damages. Hence, the structure needs to
withstand all stresses and impacts and hence needs to be designed accordingly. Chassis is
categorized into various kinds which is described in this section.
4.1.1 Backbone
Figure 3 Backbone Chassis (Harlo, 2009)
This type of chassis is connected to the front and rear suspension axles via a tabular backbone. The
backbone is what protects the inner components on which the body is placed. The backbone is
found on various sports cars providing protection against side collisions such as the very famous
Lotus Espirit.
The advantages are as follows:
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a. The entire system turns out to be reliable because of the thick tube used to cover the drive
shaft and other sensitive parts
b. Longer lifespan of the vehicle due to strength abilities to withstand torsional twist and other
wear and tear
c. Various configurations are available such as 2,3,4,5 or 6 axle vehicles
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The disadvantages are as follows:
a. The manufacturing cost is expensive because of the complexity involved requiring more
axles
b. It is a heavier structure for a given torsional stiffness
c. It doesn’t provide side impact protection
d. Repairs can be complicated
4.1.2 Monocoque
Figure 4 Monocoque Chassis (Petrol Smell, 2010)
This chassis has an advantage as shown by the figure above that it isn’t just a stress members joined
together, it is actually an integrated body which comes as a single piece. It is manufactured by a
pressing procedure conducted by a large stamping machine followed by welding. This process is very
quick and easy and hence is adopted by many companies especially those which intend to produce
for mass production.
The advantages for the monocoque are as follows:
a. Space Efficient
b. Has a good crash protection
c. Best suitable for mass production
The disadvantages are:
a. Too heavy and bulky
b. Not that strong compared to a few other chassis types
c. Impossible for small volume production
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4.1.3 Tubular Space Frame – selected design
Figure 5 Tubular Space Frame (sharma, 2012)
The best kind of chassis frame amongst the ones mentioned before is the tabular space frame. This
is because it has provides maximum strength by incorporating a system of circular section tubes as
shown in the figure above. The structure turns out to be complex after welding is completed giving a
rise to its strength. However, the frame is extremely expensive and requires a lot of time to
manufacture and assemble. Some examples are the luxurious car category such as Mercedes Benz,
Audi and other famous sport category like Ferrari and Lamborghini.
The advantages for this type of a chassis frame are:
a. Can be applied for various geometric shapes due to various support locations
b. The system comes with prefabricated components which help to shorten the time of
designing, manufacturing or installation.
c. In terms of costs, it turns out to be quite economical in the long run because it is light in
weight
The disadvantages are as follows:
a. Complicated system leading to high cost initially and a lot of time is consumed
b. Impossible for robotised production
c. Once assembled, becomes difficult to access the cabin
Based on these advantages and disadvantages, the tubular space frame is most appropriate and
hence is selected for the CAR model.
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Chassis Dimensions
Figure 5 Isometric View
Figure 6 Side View
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Figure 7 Top View
Figure 8 Front view
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4.2 Body Frame
The images below show the different views of the frame made by AutoCAD
Figure 9 Frame with lofting
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Figure 10 Side view
22
Figure 11 Skeleton View
23
Figure 12 Side view
24
Figure 13 Front View
25
Figure 14 Front View with complete body
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Figure 15 Back View
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Figure 16 Back view with skeleton
4.3 Engine
4.3.1 Hatz-Diesel 1B20
Figure 17 Hatz Dieself 1B20 (HATZ Diesel, 2013)
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This engine type is used for single cylinder diesel engines and is designed with a air-cooled single
cylinder 4 stroke diesel engine. It is a vertical cylinder with a light alloy diecast cylinder crankcase
and head and piston which allows low free forces of gravity. Lubrication is done via a pressurized
circular oil system attached with a fine filtering screen for the main flow. The valve is controlled by
rocker, push-rods and tappets.
Furthermore, the engine provides direct injection of fuel along with good cold start performance. It
gives excellent exhaust quality and isn’t sensitive to dust due to its cooling fan and AC generator
embedded in the flywheel.
This engine turns out to be most reasonable for the project giving the group the specifications
required to proceed further. Details on this engine are provided in the final design phase section.
4.3.2 Yanmar L48N
Figure 18 Yanmar L48N (yanmar industries, 2013)
This is a 4-stroke, vertical cylinder, air-cooled diesel engine with a single cylinder. The cooling system
is operated by a Flywheel Fan from which air is forced. Moreover, the lubrication system is also
forced with trochoid pump. The starting system has two options, one being electrical and the other
recoil.
4.3.3 Honda GXH 35 & GXH 50( write about the engine)
Honda Dio Engine ( Finalized Decision)( write about the engine)
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Fuel injected system & Electronic Closed Loop Engine Management (ectrons fuel injected )Write about it
4.4 Drive Mechanism
4.4.1 Flat Belt Drive
Figure 19 Flat Belt Drive (Bedroom Workshop, 2013)
The flat belt is a subcategory of the belt drive mechanism which is used widely for various
applications such as conveyors, sawmills, water pumps, electric generators etc. it is a simple system
that delivers high power and speeds approximately 500 horse power. However, due to its bulky size,
they require high tension which in turn produces higher loads leading to slipping of the belt. Hence,
the pulleys were designed in such a way having a crown shape from which the belt would stay intact
with one another.
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4.4.2 Roller Chain – selected
Figure 20 Roller chain (Mechanical Power, 2013)
Another name for this type of drive mechanism is the Bush Roller chain which is widely used to
transfer mechanical power for various industrial, domestic and agricultural applications. Some
examples are cars, motorcycles, bicycles etc. This mechanism is comprised of multiple short
cylindrical rollers connected together by side links. It also consists of a sprocket which drives the
rollers and looks like a toothed wheel as shown in the figure above. This device is known to be
simple yet very reliable and efficient in terms of power transmission.
4.4.3 VBelt / Conical Pulleys Drive – (Finalized Decision) write about it
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Steering system ( Compact Rack & Pinion with tie rods) ( Finalized
Decision)
The kind of steering system chosen by the team is the rack and pinion. The reason this was chosen is
because:
1. Provides the right angle degree which was found to be 10 degrees for the inner wheel and 8.7
degrees for outer wheel to achieve a minimum angle as per the eco shell marathoner shown
in the (calculation Index A).
2. Accurate steering feedback signals to the driver throughout the period of motion
3. Reduction in unwanted toe caused during bump steer due to the pivot points of the steering
system placed near the suspension system’s pivot points
4. Compact in size making it easily assembled and fit in the front frame of the vehicle
While designing the steering system, certain safety requirements need to be considered such as the
tie rods must be protected by the frame and suspension components to avoid impact from the front.
Moreover the adjustable rod ends must be fastened and secured tightly with the jam nuts and the
lock to lock wheel stops should be in line with the kingpin.
The category selected for the steering system was the 11 th unit because it was found to be the most
suitable in adjusting in the front frame due to the dimensions. Tie rods are made up of 12mm solid
chrome-molly material having opposite handed threads at both ends. This rod consists of a ball joint
at the end of it giving an advantage to provide greater range of motion when compared to ones that
have tube rods with hiem joints and clevis ends. Moreover, it provides angle adjustments without
having the need to disassemble the steering system.
The shaft is ¾ inches by 0.58 inches made of steel spline on one end. The spline is a universal joint
category helping to join the shaft to the rack and pinion while holding it in a place fixed with the help
of screws. The rack is joined together by bolts which are holding two plates together giving a more
stable and rigid connection helping to remove any unnecessary movements.
The steering wheel’s disconnected hub is welded to the other end of the shaft helping to give more
easy entry and exit of the driver. This shaft is further held by a Delran sleeve which is connected to
the frame.
The selection was based on the reasonable price this system has along with the hub connection and
diameter of 29.2 cm. The older designs used to use a recirculation ball mechanism most commonly
found on heavy trucks and vehicles. This ball helps to reduce a big amount of friction created during
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the operation and provides a detectable lash which holds the steering machinery allowing it not to
move.
Specification
Weight = 1.8 kg.
Foot Space is 5x7.6 cm
The rack and pinion is 28 x 5 x 6.35 cm
Tie rods and other connectors are necessary
Tie rod ends must be constrained.
Tie rods must be protected from frontal impact.
Must have wheel lock to lock stops
Figure 21 Rack and pinion components
Design Alternatives
There are a couple of steering system designs as shown below:
1. Rack and Pinion
2. Worm and nut
3. Cam and Lever
4. Ackerman
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Design Evaluation
Table 4 Steering Design Evaluation
As seen from the above evaluation, Rack and Pinion design system turns out best for this project.
This has an advantage of giving the driver a great riding experience without any reaction or slack.
The only drawback it does have is that if it stops working, it will require changing the entire unit.
The rack selected is most suitable for small cars and karts just like the purpose of this competition
and has a spline input shaft of 5/8”36 length and a ratio of 1.5 turns to 4”of travel (12:1). It weighs
approximately 2.6 pounds and has the following dimension shown below:
Figure 22 Rack and Pinion dimensions
Assembly
A hollow tube is used known as MS chromoly where the rack and pinion are connected by both the
wheels and made of chromoly material. This is mounted on the Black Widow’s chassis and is found
on the other side of the panel.
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Figure 23 Rack and Pinion Assembly
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Components
The various numbers of components are as follows:
Table 5 Steering System Components
Component Image
Wheel
Shaft
Plastic Bush Bearing
Universal Joint
Rack and pinion
Tie Rod
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4.5 Clutch
In order to engage and disengage the engine for control movement, a clutch is designed depending
on the various kinds available; CRC clutch-roto Sprocket unit, Cone clutch, Plate Clutch and
Centrifugal Clutch. This section of the report describes these various kinds of clutches.
4.5.1 CRS Clutch-rotor – selected
Figure 24 CRC Cluctch Roto
This clutch is a part of the magnetic clutch family and is the best kind for any parallel shaft drive
application. It is a single piece which comes with a pre-aligned unit containing a special adapter hub
where a plate-type socket is attached. It is available in four sizes having a range from 100lb-in to
1749lb-in for nominal static torque. Moreover, this clutch is easy to assemble and maintenance is
easy and is done quickly.
4.5.2 Cone Clutch
Figure 25 Cone Clutch (CUCDC.com, 2006)
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This clutch comes under the frictional category providing superior transmission of high torque. This
is because it gives a wedging action allowing the frictional surfaces to bond with one another.
However, due to this wedging action, more force is required to disengage the clutch. Moreover, it
takes a lot of space, is heavy and has a complex design
4.5.3 Plate Clutch
Figure 26 Plate Clutch
Similar to the cone clutch, the plate clutch also operates with the help of a friction material and plate
position between the driving shaft and driven shaft as shown above. The driven shaft gets activated
by the connection between these two surfaces when pressed producing driving friction. Moreover,
the advantage of these clutches is that they can be engaged and disengaged irrespective of the
speed with the help of a little input force. They are also lighter than the cone clutch leading to the
price being reasonable and are simple to manufacture and assemble.
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4.5.4 Centrifugal Clutch
Figure 27 Centrifugal Clutch (Dan's Motorcycle Repair Workshop, 2013)
This clutch is designed to operate using angular velocity of the engines drive shaft in order to extend
a rotating mass. This is necessary because it creates pressure between two friction surfaces helping
to transmit power to an output shaft.
The clutch operates such that at lower velocities the clutch is disengaged. This is because the output
mechanism isn’t able to lock due to the low centrifugal force applied. Once the velocities increase,
power is transmitted successfully. These clutches produce high torque at low velocities due to the
disengaged clutch, but at higher velocities work best giving high efficiency. The drawbacks are that a
lot of energy is wasted during this transition stage.
Based on the literature view and data collection and calculations done in Index A the clutch was
selected. The basic requirement of the clutch is to act as a engage disengage clutch. And the
following dates required by the Engine. The engine maximum Horsepower is 4.5hp and the torque is
found to be 9.5 Nm. therefore the CRS clutch was selected for it had a 21 hp and torque 31 Nm (see
index B) and the best rating among other type of clutch due to the fact that it will save us the effort
of having to make an independent clutch instead it will be mounted directly to the engine and that
its price is considerable.
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4.6 Transmission
4.6.1 Continuously variable transmission
From the term “continuously” one can tell that it is a transmission which can change without any
steps through an infinite number of effective gear ratios which range from maximum to minimum
values. In other words, the CVT’s input shaft remains in constant angular velocity over a wide range
of output velocities.
This system provides better fuel economy compared to others because at different available speeds
the engine runs with extremely efficient revolutions per minute (RPM). Hence, at a certain RPM the
engine provides its maximum efficiency and utilizing this advantage the design can be made in such a
way that it operates at that specific RPM.
4.6.2 Sprocket and Derailleur Transmission
Figure 28 Front (left) and Rear (right) Derailleur Transmission (Wikipedia, 2012)
This is a different type of transmission which utilizes different gears having variable ratio
transmission. It consists of a chain, multiple sprockets available in different sizes and a mechanism
which helps to move the chain from one sprocket to another.
It consists of front and rear derailleur where the front derailleur moves the chain side by side from
the front chain rings while maintaining the tautness of the top portion of the chain. It also
accommodates various chain ring sizes ranging from 20 to 53 teeth. The rear derailleur is in charge
of two duties. The first one is to move the chain from the rear sprockets to a smaller one by taking
the chain slack. Then it positions itself in the path of the bottom slack portion of the chain.
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4.7 BrakeThe requirements for this project is either to have two independently activated braking system
where one is for the front wheel and the other for the rear or the other option is to have a single
system connecting both the wheels via a shaft. When the drive presses the brake pedal, both
systems should come to a halt with his one hand placed on the wheel. There are different kinds of
braking systems used in cars out of which some are as follows:
4.7. 1 Hydraulic Rim Brakes
Figure 29 Hydraulic Rim Brakes (Togoparts.com, 2013)
These are not widely used but can be found on bicycles mounted on pivot points which are used as
cantilevers or for linear-pull brakes. Sometimes these are also mounted on four-bolt brake mounts
which are often found on mountain bikes. These became less common by the year 1990 because
disc brakes came into existence. These breaks provide better power and control compared to cable
actuated rim brakes due to their weight and complicated system.
4.7.2 Roller Cam Brakes
Figure 30 Roller Cam Brakes (Bike Stash, 2013)
These brakes come under cantilever bakes which are actuated by a cable being pulled from a single
two-sided sliding cam lever. When this lever is pressed against the follower surface the arms are
spread wide apart. This movement leads to a halt in the system due to the brake shoe being forces
against the rim towards the inside. This lever provides an advantage because it helps to control the
rate off closure as well as the force can be made non-linear by the help of the pulling force
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experienced. Because of this reason, it is found to be more preferred due to having a maximum
clamping force compared to others.
These brakes are strong and provide great control. However, they can be quite complicated and hard
to assemble as well as require a lot of maintenance due to the wear and tear experiences from
severe conditions.
4.7.3 Hydraulic Disc Brakes – selected
Figure 31 Hydraulic Disc Brake (Performance Bicycles, 2013)
A single disc brake consists of the following:
1. Handlebar-mounted lever
2. Frame/fork mounted calliper
3. Hub mounted rotor
As soon as the level is pressed a friction material known as the brake pad clamps onto the rotor
producing a frictional force on the rotor/calliper interface which helps to slow down the vehicle by
converting its kinetic energy into heat energy.
The hydraulic disc brake consists of a master piston which is a part of the level, a hydraulic brake
line, multiple opposing slave pistons in the calliper and a hydraulic fluid known as brake
fluid/mineral oil. Once the level is pulled, the master piston is pushed into the lever body forcing
fluid flow into the slave pistons. These pistons include brake pads which clamp onto the rotor when
these fluids are released. An additional force is also created due to the pressure increase in the
system which in turn produces an even stronger clamping force on the rotor.
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The figure below gives an overall view of the system and how it works:
Figure 32 Hydraulic Disc Brake System
The hydraulic disc brake has been selected because of the requirement which was mentioned
initially, calculations, as well as due to its many advantages helping to make a better CAR Model.
The brake specification is summarized in the following table:
Table 6 brake specification
Weight 380 gramsLever Material Aluminum lever, Aluminum BodyCaliper Design 2 Piston, Forged 2-piece AluminumFinish Black, WhiteRotor HS1 (140mm rear) 160/170/180/200mmPad Organic, Top LoadingFluid DOT 5.1Mount AmbidextrousAdjustment Reach Adjustment, Special Features TaperBore Technology, MatchMakerX CompatibleTechnology Highlight(s) TAPERBORE TECHNOLOGYIntended Use XC/Trail/AMSystem HydraulicRotor Sizes 140/160/170/180/200
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Tri-Align Caliper Positioning System noTool-Free Pad Replacement NoSpeed Dial NoBend Zone™ YesAmbidextrous YesStainless Hardware NoOther 2 hose angles for clean routingRetail Availability August 2012
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4.8 Auxiliary
Electrical components and wiring
There are three places to locate the emergency switch, one inside the cabin and the other two outside the cabin in left and right side. Emergency stop button (2) which is connected direct with battery (1). From the emergency stop, all the connection will come to solenoid contact switch. From that solenoid wires will come out to be input to the following: ignition switch, voltage regulator and horn switch. The two emergency stop button left and right will be in sires to the relay contact (3) when it energize it will make the solenoid valve (4) open to let the fuel goes in the engine. There are two connections from the ignition switch one to the electrical clutch switch (9) and the other to the brake light switch (10). For optional indicators such as break lights (11).
1.
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4.9 Final Design
The final Black Widow proposed Design selection is based on the literature review, calculation and assembly made up of the chosen components discussed above. The flowchart below illustrates the final design component selection:
Figure 33 Final Design Flowchart
The Total Wight of the vehicle can be estimated based on the components selected on the literature review and the calculation done
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Project CAR
Chassis
Tubular Space Frame
Body Frame
Droplet like Shape
Engine
Hatz Diesel 1B20
Drive Mechanism
Roller Chain
Clutch System
CRS Clutch-Roto
Transmission
Nuvinci Transmission
Brake
ELIXIR 5 Hydraulic Disc
Brake
Auxiliary
5. Engineering Design Process
5.1 Engine Modification and Mounting No progress
5.2 Fuel System
Fuel consumption is the amount of fuel used per unit distance; for example,
litters per 100 kilometres (L/100 km). In this case, the lower the value, the more
economic a vehicle is (the less fuel it needs to travel a certain distance). Efficiency is
defined as output per input. In automobiles it is the distance travelled per unit of fuel
used; in miles per gallon (mpg) or kilometres per litre (km/L). There for our aim is
basically to optimise the fuel usage and engine performance through finding out the
optimum speed and the most advantageous engine RPM that serves our purpose. From
the calculations (Index A) and previous year’s races we found that the best speed used
in the previous year’s competition is 30 meter per second, and the best Engine RPM is
1200 rpm. This will give us a Fuel consumption of about 68 kilometer per liter which is
equivalent = 159.2124 mpg.
Fuel efficiency is dependent on many parameters of a vehicle, including its engine
parameters, aerodynamic drag, weight, and rolling resistance. There have been advances in
all areas of vehicle design in recent decades. An actual mpg figures can be determent after the
testing the car.
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Figure 34 Fuel System
ConclusionWrite something
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