ABSTRACT
This motorized Two-wheel scooter is specifically designed for low speed, and hence is more suitable for short distance commute. It incorporates a mild steel frame which houses the transmission mechanism. This transmission system in its self is a motor- chain-sprocket assembly: a 350w DC motor powered by a 24v, 18A battery generates sufficient torque which is transmitted by a 16 toothed sprocket through a chain comprising of 64 links to a rear sprocket (22 teeth) attached to the rear wheel. On either side of the handle bar is the brake lever (left) and speed controller (right) for ease of navigation. The stress analysis reviled that the maximum stress induced on the frame due to design load is 49.156N/m2. The maximum design load of this scooter is 686.7N, and from the graph analysis the scooter travels at a maximum velocity of 0.51m/s. The graph also reviled that the velocity of the scooter is inversely proportional to the load. Similarly, the discharge rate of the battery increases as the load is increased. Also, the scooter velocity is directly proportional to the rate of battery discharge. The continuous working time of the battery is 40min at rated load and normal working condition. This scooter apart from providing a reliable transportation alternative provide reprieve for the severely threatened ozone layer and the environment in general being that it is toxic emission free.
TABLE OF CONTENTS
Cover page i
Title page ii
Certification iii
Approval iv
Dedication v
Acknowledgement vi
Abstract vii
Table of Contents viii
List of Tables ix
List of Figures x
List of Symbols and Abbreviations xi
CHAPTER ONE
Introduction 1
- Background of study 1
1.2 Problem Statement 3
- Aim and Objectives 4
- Significance of The Project 4
- Scope and Limitations 5
CHAPTER TWO
2.0 Literature Review
2.1 Kick Scooter 6
2.2 Electric Kick Scooter 8
2.3 Electric Motor 9
2.3.1 Brushed Electric Motor 9
2.3.2 Brushless Electric Motor 10
2.3.3 Hub Motor 11
2.4 Electric Scooter Battery 12
2.4.1 Nickel Metal Hydride Battery (NiMH) 12
2.4.2 Sealed Lead Acid Battery (SLA) 13
2.4.3 Lithium-ion Battery (Li-ion) 14
2.5 The Electric Scooter Speed Controller 15
2.6 Mobility Scooter 16
2.7 Motor Scooter 19
2.8 Solar Electric Scooter 20
2.9 Hybrid Scooter 22
2.10 Pedal Scooter 22
2.11 Pedal Scooter 23
CHAPTER THREE
3.0 Materials and Methods 26
3.1 Principle of Operation 26
3.2 Functional Design 27
3.2.1 Design Philosophy 27
3.2.2 Design Considerations 28
3.2.3 Components of the Machine 28
3.2.4 DC Motor 29
3.2.5 Sprockets Selection 32
3.2.6 Chain Dimensions 33
3.2.7 Battery 34
3.2.8 Frame Design 35
3.2.9 Speed Control Mechanism 38
3.3 Machine Construction 39
3.4 Bill of Engineering Measurement and Cost Evaluation 40
3.4.1: Bill of Engineering Measurement (BEME) 40
CHAPTER FOUR
4.0 Results, Observations and Discussion 42
4.1 Machine Testing 42
4.1.1 Procedures for Test Running the Motorized Scooter 42
4.2 Results 42
4.3 Discussion 46
4.3.1 Machine Efficiency 46
4.3.2 Scooter Maintenance and Safety 47
CHAPTER FIVE
5.0 Conclusion and Recommendations 49
5.1 Conclusion 49
5.2 Recommendations 50
References
Appendix
List of Symbols and Abbreviations
| S/N | Symbols/Abbreviations | Meaning | Unit |
| 1 | A | Current (Ampere) | Amp |
| 2 | CAD | Computer Aided Design | |
| 3 | C | Center distance | in |
| 4 | cm | Centimetre | cm |
| 5 | mm | Millimetre | mm |
| 6 | Inch | Inches | in |
| 7 | kg | Kilogram | Kg |
| 8 | L | Chain length | pitche |
| 9 | m | Meter | m |
| 10 | N | Newton | N |
| 11 | RPM | Revolutions Per Minute | N |
| 12 | V | Velocity | m/s |
| 13 | W | Watt | |
| 14 | P | Power | w |
| 15 | Ʈ | Torque | N-m |
| 16 | η | Efficiency | % |
| 17 | % | Percentage | |
| 18 | π | Pi | |
| 19 | ω | Angular Velocity | Rad/ |
| 20 | Ω | Resistance | Ohms |
| 21 | σ | Principal/Normal Stress | N/m2 |
| 22 | τ | Shear Stress | N/m2 |
List of Figures
Fig.2.1 Pictorial view of a kick scooter (made by Razor)
Fig.2.2 Pictorial view of an electric kick scooter
Fig.2.3 Solar electric scooter
Fig.2.4 Pedal scooter
Fig.2.5 Volker et al Pedal Scooter
Fig.3.1. Complete isometric view of the scooter design without coverings
Fig.3.2 DC motor
Fig.3.3 Sprockets
Fig.3.4 Scooter Frame
Fig. 4.1 Graph of load against velocity
Fig. 4.2 Graph of load against battery discharge time
Fig. 4.3 Velocity against discharge graph for design load
List of Tables
Table 3.1 battery current and corresponding resistance required
Table 3.2 Bill of engineering measurement
Table 4.1 Speed for various test load range
Table 4.2 Discharge rate for designed load (686.7N) at various speed
CHAPTER ONE
INTRODUCTION
1.1 Background of study
In recent years, there have been increasing government and public interest in energy issues generally and particularly in electro-mobility. This is so because of the increasing effect of fossil fuels burnt by the automobile on the natural environment as well as on human health. A research carried out by (Ojolo S.J. et al, 2017) on the effect of vehicles emissions on human health in Nigeria showed significant physical effect of these emissions on vegetation’s, buildings and on structures.
The results from the research on health also showed on the average that 28.3%, 16.6%, 23.3%, 18.3%, 13.3% of the population of people living in the neighborhood (Lagos-Oshodi,Mushin,Apapa and Fola Agara all in Nigeria) under study were affected by sleeplessness, running nose, heavy eyes, asthmatic attack and headache respectively.
To contend this menace, a lot of electro-mobile devices as well as solar powered automobiles have evolved. In the year 2015, the global threshold of electric cars on the road rose from 1 million to 1.26 million (Electric Vehicle Initiative, 2017) this shows the joint commitment of the government and industries towards securing affordable and clean energy for the human society.
A recent statement by the Chartered Institute of Logistics and Transport revealed that in Nigeria over 7 million vehicles ply the roads daily out of which 99.8% operate on fossil fuels (www.allafrica.com/stories).
It is unfortunate that even short distance transport systems in Nigeria still uses fossil fuel as it source of power which in its little way contributes to the degradation of the environment as well as the health of humans in the surrounding. The high risk of accidents in congested areas as well as high traffic noise warrant us to begin to consider a simpler, more economical and environment friendly means of transportation which can be adopted for use within short distances e.g. across companies complex, colleges campus, hospitals etc. There are several versions of scooters ranging from; the pedal scooters, electric scooters, internal combustion engine (motorized) scooters, kick scooters etc.
At the African Voices Series, (Adelekan, 2016) presented a lecture in which he highlighted some significant facts about the Nigerian Transport System. It was noted in the lecture that the demand for transport services in Nigeria exceeds the supply. The transport sector contribution to Nigeria’s GDP was given as 3%, with road transport being the predominant mode and accounts for more than 90% of the sub-sector’s contribution to the nations GDP. The total road network was stated as 200,000 km, out of which 65,000 km are bituminous roads.
Electric scooter as a means of transportation has not really been embraced by the Nigerian populace. The reason for this is not far-fetched from the cost of acquiring a unit of the current modern design and the opulence attached to its ownership. Consequently, electric scooters are thus seen as a luxury property rather than a bio-friendly alternative to greenhouse emission by conventional means of transportation. It is thus a no brainer what a low budget electric scooter will do not just to the economy(less spending on shuttle runs, less down time as a result of trekking between institution’s/company’s complex, more productivity), but also to the environment (less dependence on fossil fuel, less harmful gas emission, less noise pollution ).
The Nation’s population has skyrocketed, and finding convenient modes of transportation are high in demand. In Nigeria, people who ride on bicycles or kick scooters are seen as belonging to the lower socioeconomic class or simply unserious. No doubt, riding on a bicycle or a kick scooter aside from offering a relatively higher speed compared to trekking, is strenuous and energy sapping due to the need to continuously cycle the pedal as in the case of a bicycle or push ones foot against the ground as in the case of a kick scooter. For these reasons, the populace seem to pay less attention to them (bicycles and kick scooters), or use them as equipment for exercise rather than for transport. The emergence of electric scooter would address this issue as it does not require the riders’ effort for motion.
The electric scooter affords any millennia (age group) the freedom to make some short commutes. Perfect for students seeking to zip from class to class, and great for any fast-paced commuter looking to ditch their bus pass or cut down on hefty fuel prices–the electric scooter is estimated to become the must-have transportation means in the next two decades (https://swagtron.com).
With urban populations only on the rise, it’s time to put our minds to the proactive grindstone. Because too many cars already on every freeway and trains and buses struggling to keep up with each cities multiplying population, the time is rapidly approaching for commuters to take their transportation into their own hands.
1.2 Problem Statement
Road traffic depends on the pattern of human settlement, for this reason every type of road transportation means is not suitable for every settlement. Considering the high cost of transporting in commercial vehicles daily, the cumulative adverse effect of these commercial vehicles (which uses fossil fuel) on the environment and on the users, the time wastage in waiting to board a commercial vehicle, the inconveniences in accumulating many people per seat to get to a “stone throw” distance all gives enough reason to seek a more convenient, environment friendly and economically viable means of transporting people across short distances.
1.3 Aim and Objectives
The aim of this project is to design and construct an environment friendly low cost motorized scooter. To achieve this aim, the following objectives are to be followed;
- To design and construct a frame that will carry/support every other component of the scooter as well as the rider’s weight
- To design and set up the power transmission system (made of chain and sprocket) to transmit to the rear wheel
- To design and construct the handle bar to be attached to the front wheel for navigation
- To design and incorporate a braking system to be attached to the rear wheel
- To design a control module for switching on/off the scooter.
1.4 Significance of the Project
This project is designed to bridge the gap in short distance transportation across cities, colleges, hospitals, company complex etc. it will eliminate the need to wait for minutes or hours just to board a taxi to the next street. It will foster convenience in movement of people across short distances, save the environment in its little way from the harms of fossil fuel and cut the high cumulative cost of transportation across moderate distances on daily basis.
1.5 Scope and Limitations
The electric scooter in this project is designed to accommodate only the rider and its safe load should not exceed 60 kg mass. It does not provide for high speed, hence it is suitable for short distance commute and should not be used on highways.
