A SEMINAR REPORT ON

AUTOMATIC GEAR SHIFTING IN TWO

WHEELERS

Submitted in partial fulfillment of the requirements for the

Award of the degree of

BACHELOR OF TECHNOLOGY

In

MECHANICAL (AUTOMOBILE) ENGINEERING

Submitted by

ZIYAD A 12402063

DEPARTMENT OF MECHANICAL ENGINEERING

SREE CHITRA THIRUNAL COLLEGE OF ENGINEERING

THIRUVANANTHAPURAM 695 018

SEPTEMBER 2015

SREE CHITRA THIRUNAL COLLEGE OF ENGINEERING,

THIRUVANANTHAPURAM – 695 018.

DEPARTMENT OF MECHANICAL ENGINEERING.

CERTIFICATE

Certified that seminar work entitled “AUTOMATIC GEAR SSHIFTING TWO

WHEELERS” is a bonafide work carried out in the seventh semester by “ZIYAD A

(12402063)” in partial fulfilment for the award of Bachelor of Technology in

“MECHANICAL (AUTOMOBILE) ENGINEERING” from University of Kerala during

the academic year 2015-2016 who carried out the seminar work under the guidance and no

part of this work has been submitted earlier for the award of any degree.

SEMINAR CO-ORDINATOR SEMINAE GUIDE

E.JAYAKUMAR U.PRAKASH

Assistant Professor Associate Professor

Department of Mechanical Engg. Department of Mechanical Engg.

SCT College of Engineering, SCT College of Engineering.

Thiruvananthapuram-18. Thiruvananthapuram – 18.

HEAD OF THE DEPARTMENT

Dr. S. H. ANILKUMAR

Department of Mechanical Engg.

SCT College of Engineering,

Thiruvananthapuram – 18

ACKNOWLEDGEMENT

First and foremost, I am extremely happy to mention a great word of gratitude to

Dr.S.H.ANILKUMAR, Head of the Department of Mechanical Engineering for providing

me with all the facilities for the completion of this work.

I wish to place on records my ardent and earnest gratitude to my guide Sri. U.PRAKASH.

His tutelage and guidance was the leading factor in translating my efforts to fruition. His

prudent and perspective vision has shown light on my trail to triumph.

Finally yet importantly, I would also like to express my gratitude to our seminar coordinator,

Sri. E JAYAKUMAR for his valuable assistance provided during the seminar. I would also

like to extend my gratefulness to all the faculty and staff members in the Department for the

help and support rendered to us within the department. I would also like to thank all my

friends who greatly helped me in this effort.

ZIYAD A

.

ABSTRACT

Motorcycle is widely used around the world and particularly in India. The gear shifting

system of the motorcycle is conventionally manual. This paper covers development of an

indigenous automatic gear shifting/changing system for the standard motorcycle. By this

system the manual mechanical gear-shifting system will remain unchanged because an

additional electromechanical system is placed on the vehicle to shift the gear and for

automatic controlling the clutch. So the system has both the options manual as well as

automatic. This system uses low-cost microcontrollers to make the accurate decision for

shifting the gear up and down by observing the speed, and it controls the clutch transmission

where necessary. The complete hardware and software has been tested and the functioning of

the automatic gear shifting system is verified. This system is flexible and can be used with

any motorcycle manufactured ranging from 50cc to 200cc.

(iii)

TABLE OF CONTENTS

ACKNOWLEDGEMENT iii

ABSTRACT iv

LIST OF FIGURES v

Chapter Title. Page No.

1. Introduction 1

2. Sensors used in the system 2

2.1. Wheel speed sensor 2

2.2. Throttle position sensor 3

3. Transmission controller unit 5

3.1. Microcontroller unit 6

3.2. Working of microcontroller 8

3.3. Program logic for gear shifting microcontroller 9

3.4. Program logic for the clutch controlling microcontroller 10

4. Actuators 11

4.1. Electromechanical actuator 11

4.2. Pneumatic actuator 12

4.3. Hydraulic actuator 12

5. CONCLUSION 13

6. SCOPE OF FUTURE WORK 14

APPENDIX - 1 15

REFERENCES 20

(iv)

LIST OF FIGURES

Sl. No. Title Page No

2.1

Pulse wheel

3

2.2 Wheel speed sensor 3

2.3 Throttle position sensor 4

3.1 General block diagram of CPU (Microprocessor) 6

3.2 Microcomputer block diagram 7

3.3 A block diagram of a microcontroller 8

4.1 Hydraulic actuator 11

4.2 Pneumatic Actuators 12

4.3 Electro mechanical actuator 12

(v)

1

CHAPTER 1

INTRODUCTION

In our developed system, both the gear and the clutch are controlled electromechanically by a

microcontroller-based computer system. This system does not require any modification to the

engine. The equipment is mounted externally on the body of the motorcycle. The system

shifts the gear up and down electro-mechanically like a human rider by sensing the speed of

the vehicle, but the system shifts the gear at exactly the correct speed, which produces the

smooth gear changing sequence. The engine runs smoothly and without any knocking, which

increases the engine life. This system is different than the traditional automatic transmission

used in cars, because it uses manipulators/electro-mechanical devices, which act similar to

the human foot pressing the gear pedal up and down, and pressing the clutch lever like a

human hand. Automatic gear shifting can be divided into three basis on the mechanism of

actuators used Electro mechanical, Pneumatic and Hydraulic.

2

CHAPTER 2

2. Sensors used in the system

Wear of brake materials can be measured by using 3 different devices:

(i) Wheel speed sensor

(ii) Throttle position sensor

(iii) Load sensor

2.1. Wheel speed sensor

The intelligent data communication of the electronic vehicle systems is supported by sensors

[2]. In relation to driving safety, wheel speed sensors are of particular importance and are

used in numerous applications in various vehicle systems. In driver assistance systems such

as ABS, TCS, ESP or ACC, motor control units use these sensors to determine the wheel

speed. Via data lines, the wheel speed information from the Anti-Lock Brake System (ABS)is

also provided to other systems (engine management, gearbox and chassis control systems and

navigation systems).Due to this variety of applications, wheel speed sensors make a direct

contribution to driving dynamics, driving safety, driving comfort and reduced fuel

consumption and emissions.

Based on their mode of functioning, wheel speed sensors are classified into active and

passive sensors. A clear assignment is not defined. In the garage, the following definition has

established itself. If a sensor becomes "active" only when a power supply is connected to it

and if it then generates an output signal, it is called "active" .If a sensor works without an

additional power supply, then it is called "passive".

2.1.1 Signal processing

Wheel speed sensors are installed directly above the pulse wheel, which is connected to the

wheel hub or the drive shaft. The pole pin inside a coil is connected to permanent magnet and

the magnetic field extends to the pulse wheel. The rotational movement of the pulse wheel

and the associated alternation of teeth and gaps effects a change in the magnetic flux through

the pulse wheel and the coil. The changing magnetic field induces an alternating voltage in

the coil that can be measured. The frequencies and amplitudes of the alternating voltage are

related to the wheel speed (Fig. 1). Passive inductive sensors do not need a separate power

3

supply from the control unit. As the signal range for signal detection is defined by the control

unit, the amplitudes must be within a voltage range. The distance (A) between sensor and

pulse wheel is determined by the axle design

Fig 2.1: Pulse wheel

Fig 2.2: Wheel speed sensor

2.2. Throttle position sensor

Today’s vehicles have a variety of sensors to keep the engine control computer informed

about various operating conditions. One of these is the Throttle Position Sensor (TPS), which

tracks the opening and closing of the engine’s throttle. The throttle plate is a valve inside the

carburetor or fuel injection throttle body that allows air and fuel (or air only in the case of

multiport fuel injection) to be pulled into the engine by intake vacuum when the gas pedal is

depressed. The throttle opening determines the engine’s power output, so monitoring the

position of the throttle gives the computer information it needs to determine engine load. This

information along with input from other sensors such as the manifold absolute pressure

(MAP) sensors and temperature sensors, then is used to calculate the engine’s fuel

requirements, spark timing and other functions. How It Works the TPS is a three-wire,

variable resistor (potentiometer) that changes resistance as the throttle opens. The TPS is

4

provided with a voltage reference signal from the computer (VRef), usually 5 volts. As the

position of the throttle changes, the corresponding change in the TPS’s internal resistance

alters the voltage signal that returns to the computer via signal wire. The third wire provides a

ground connection. So what the computer sees is a variable voltage signal that changes in

direct proportion to the throttle position. Most TPS sensors provide just under one volt at idle

with the throttle closed, and up to five volts at wide-open throttle. The TPS is attached to the

throttle shaft and may be located on the outside of the fuel injection throttle body or

carburetor, or on some applications, inside the carburetor itself. On some applications, there

may also be a separate “nose” switch to detect when the throttle is at idle, and/or a wide-open

throttle switch.

Modern day sensors are non-contact type. These modern non-contact TPS include Hall effect

sensors, Inductive sensors, magneto resistive and others. In the potentiometric type sensors, a

multi-finger metal brush/rake is in contact with a resistive strip, while the butterfly valve is

turned from the lower mechanical stop (minimum air position) to WOT, there is a change in

the resistance and this change in resistance is given as the input to the ECU.

Fig 2.3: Throttle position sensor

5

CHAPTER-3

3. Transmission controller unit

3.1. Microcontroller and microprocessor

Microcontrollers have only been with us for a few decades but their impact (direct or

indirect) on our lives is profound [3]. Usually these are supposed to be just data processors

performing exhaustive numeric operations. But their presence is unnoticed at most of the

places like • At supermarkets in Cash Registers, Weighing Scales, etc. • At home in Ovens,

Washing Machines, Alarm Clocks, etc. • At play in Toys, VCRs, Stereo Equipment, etc. • At

office in Typewriters, Photocopiers, Elevators, etc. • In industry in Industrial Automation,

safety systems, etc. • On roads in Cars, Traffic Signals, etc.

A controller is used to control some process. At one time, controllers were built exclusively

from logic components, and were usually large, heavy boxes. Later on, microprocessors were

used and the entire controller could fit on a small circuit board. This is still common– one can

find many controllers powered by one of the many common microprocessors (including Zilog

Z80, Intel 8088, Motorola 6809, and others). As the process of miniaturization continued, all

of the components needed for a controller were built right onto one chip. A one chip

computer, or microcontroller was born. A CPU built into a single VLSI chip is called

microprocessor. The simplified block diagram of the CPU is shown in the Fig 4 . It contains

arithmetic and logic unit (ALU), Instruction decode and control unit, Instruction register,

Program counter (PC), clock circuit (internal or external), reset circuit (internal or external)

and registers. For example, Intel 8085 is 8-bit microprocessor and Intel 8086/8088 is 16-bit

microprocessor. Microprocessor is general-purpose digital computer central processing unit

(CPU). The microprocessor is general-purpose device and additional external circuitry are

added to make it microcomputer

6

Fig 3.1: General block diagram of CPU (Microprocessor)

A digital computer having microprocessor as the CPU along with I/O devices and memory is

known as microcomputer. The block diagram in the Fig 5 shows a microcomputer.

7

Fig 3.2: Microcomputer block diagram

A microcontroller is a highly integrated chip, which includes on single chip, all or most of the

parts needed for a controller. The microcontroller typically includes: CPU (Central

Processing Unit), RAM (Random Access Memory), EPROM/PROM/ROM (Erasable

Programmable Read Only Memory), I/O (input/output) – serial and parallel, timers, interrupt

controller. For example, Intel 8051 is 8-bit microcontroller and Intel 8096 is 16-bit

microcontroller.

By only including the features specific to the task (control), cost is relatively low. A typical

microcontroller has bit manipulation instructions, easy and direct access to I/O (input/output),

and quick and efficient interrupt processing. Fig 6 shows the block diagram of a typical

microcontroller.

8

Fig 3.3: A block diagram of a microcontroller

3.2. Working of Microcontroller

3.2.1 Program logic for the gear shifting microcontoller

When power is supplied to the system, MCU1 first brings the motorcycle gears into neutral

by signaling the gear shifting system backward until the gears come to the neutral position

[1]. It will then wait for a triggering signal from the SPDT switch to execute its next

instruction. When an active low signal is received from the switch, MCU1 then waits for the

active low signal from MCU2. MCU2 senses the brake operation by receiving an active high

signal from the brake sensing system, and then sends a signal to the clutch controlling system

to press the clutch, and produces an active low signal for MCU1.

The MCU1 sends a signal to the gear shifting system to shift the gear up and stores the value

1 recording that the motorcycle is in first gear. MCU1 constantly monitors the three signals

coming from the speedometer

When there are three active high signals coming from speedometer, this indicates that the

vehicle’s speed is below 10 km/h, and the motorcycle should be running in first gear. When

9

running in first gear, the MCU1 provides an active high signal to MCU2, which causes

MCU2 to release the half clutch, not the full clutch, because the motorcycle is starting from 0

km/h and its momentum is very low. So in order to run the engine smoothly, half clutch need

to be released.

As the speed increases above 10 km/h, MCU1 recognizes one active low signal and two

active high signals. The MCU1 considers the motorcycle should be in second gear. MCU1

now signals the gear shifting system to shift the gear up and signals MCU2 to press the

clutch. When the clutch is pressed, the active low signal is sent by MCU2 to MCU1, which

then switches off the spark plug coil/ignition coil. As soon as the gear is shifted up, MCU1

switches on the spark plug coil, sends an active low signal to MCU2 to release the clutch, and

stores the value 2, recording that the motorcycle is in second gear.

As the speed increases beyond 30 km/h, two active low signals and one active high signal are

provided by the speedometer to MCU1. MCU1 now has to bring the motorcycle into third

gear. It signals the gear shifting system to shift the gear up and signals MCU2 to press the

clutch. When the clutch is pressed, the active low signal is sent by MCU2 to MCU1, which

switches off the spark plug coil/ignition coil. When the gear is shifted up, MCU1 switches on

the spark plug coil, sends an active low signal to MCU2 to release the clutch, and stores the

value 3, recording that the motorcycle is in third gear.

As the speed increases above 45 km/h, the speedometer sends three active low signals to the

MCU1. MCU1 consider the vehicle should be in fourth gear. MCU1 signals the gear shifting

system to shift the gear up and signals MCU2 to press the clutch. When the clutch is pressed,

the active low signal is sent by MCU2 to MCU1, which switches off the spark plug

coil/ignition coil. When the gear is shifted up, MCU1 switches on the spark plug coil, sends

an active low signal to MCU2 to release the clutch, and stores the value 4, recording that the

motorcycle is in fourth gear

Let us now suppose that the speed of the vehicle starts to decrease. As it becomes lower than

45 km/h, the speedometer signals two active low and one active high signal to the

microcontroller which causes MCU1 to bring the motorcycle into third gear. MCU1 now

signals the gear shifting system to shift the gear down and signals MCU2 to press the clutch.

When the clutch is pressed, the active low signal is sent by MCU2 to MCU1. When the gear

10

is shifted, MCU1 subtracts 1 from the stored value resulting in 3, and the motorcycle is in

third gear.

Suppose the speed of the vehicle decreases below 10 km/h; then the speedometer sends three

active high signals to MCU1. This signal causes MCU1 to bring back the engine into first

gear. Now the MCU1 signals the gear shifting system to shift the gear down and it sends an

active high signal to MCU2 to press the clutch. When the clutch is pressed, MCU2 produces

an active low signal and sends it to MCU1. Now MCU1 subtracts 1 from the stored value.

If this value is 1, then MCU1 does nothing more than monitoring the speed of the vehicle. If

the value is greater than 1, then MCU1 repeats the above process up to the subtraction of 1

from the stored value and checks whether it is now 1 or not. If it is still not 1, then MCU1

repeats the process until the value equals 1. It then stops performing the process and goes

back to monitoring of speed of the vehicle.

If the speed of the vehicle is lower than the programmed speed limit for the current running

gear, then MCU1 shifts the gear down by performing the operation defined above, for

shifting the gear down until the specified gear is engaged. If the speed of the vehicle is

greater than the programmed speed limit for the current gear, then MCU1 shifts the gear up in

order to bring the motorcycle into the correct gear by performing the gear shifting up

operation as defined previously.

3.2.2 Program Logic for the Clutch Controlling Microcontroller

MCU2 constantly monitors the active high signal from the brake sensing system and MCU1.

If either of these systems sends an active high signal for MCU2, it presses the clutch. When

there is no active high signal to MCU2, it releases the clutch and sends an active low signal to

MCU1.When the clutch is not pressed it sends an active high signal to MCU1. When the

motorcycle is in first gear, an additional active high signal is sent by MCU1 to MCU2. When

MCU2 receives this active high signal after pressing the clutch, it releases the half clutch.

This condition is only valid for first gear, and for all other gears, MCU2 will release the full

clutch. The main function of MCU2 is to monitor the active high signals sent by MCU1 and

the brake sensing system, to press the clutch, and if there are no active high signals from any

of the systems, MCU2 will release the clutch.

11

CHAPTER-4

4. Actuators

To achieve the goals of automation and process control, the computer must collect data from

and transmit signals to the production process [5]. This is done by using hardware

components that act as intermediaries between the control system and the process itself. In

the last unit process variables and parameters were defined as being either continuous or

discrete. The control computer tends to use digital discrete (binary) data, however some of

the data from the process may be continuous and analogue. Therefore we must have some

way to accommodate this within the system, so that analogue data can be read in a digital

format, and vice-versa.

An actuator converts the controller command signal into a change in a physical parameter.

This change is usually a mechanical alteration, such as a change in position, or a change in

velocity. Just like the sensor, an actuator is also a transducer, as it changes one type of

physical quality into another. Many actuators are fitted with amplifiers, to covert low level

control signals into strong signals sufficient to drive the actuator.

Three types of actuator may be defined: electrical, hydraulic, and pneumatic. Electrical

actuators include electric motors of all kinds, stepper motors and solenoids; hydraulic

actuators includes a wide variety of cylinder-devices compressing hydraulic fluids, typically

oils or water-oil solutions, to achieve operation; while pneumatic actuators include a variety

of piston-and-cylinder devices that compress air or other gases to achieve changes in the

physical variables.

Fig 4.1: Hydraulic actuator

12

Fig 4.2: Pneumatic Actuators

Fig 4.3: Electro mechanical actuator

13

CHAPTER-5

CONCLUSION

A complete indigenous automatic gear system for a motorcycle has been

developed. This system is very useful for physically disabled persons, such as those who do

not have a left leg and left hand. By using this system, only one hand is needed for

controlling the motorcycle. Since this system changes the gear at the correct speed,

motorcycle engine life is increased. Also, it provides a resistance against knocking, and it

improves fuel consumption. This system is also very helpful for learner riders of the

motorcycle.

This system is flexible and can be implemented on any motorcycle available in the Pakistani

market without any major changes. The motorcycle manufacturing companies can also use

this system in their vehicles because it can be easily fitted to the motorcycle and there is no

need of internal modification of the gear system. By installing this low cost system in their

motorcycle, companies may be able to increase their sales due to the availability of these new

features. Some sport riders may also enjoy the benefits of the automatic transmission.

14

CHAPTER-6

SCOPE OF FUTURE WORK

In this system the automatic gear shifting is done by monitoring the vehicle speed. It could

instead be done by monitoring the crankshaft RPM or the engine’s acceleration. The electro-

mechanical system has to be made more efficient, faster and more reliable. We have used two

extra DC self-starter motors taken from 300 cc motorcycles, because they are powerful

enough to shift the gear and control the clutch. A future improvement of the system could use

a DC actuator, which is powerful enough to shift the gear and control the clutch, and

consumes less power or only the power available in a traditional motorcycle battery.

The electro-mechanical system can be made more compact so it can easily be fitted in

existing motorcycle chassis without disturbing the other components. The microcontrollers

can be replaced by automotive microcontrollers. A more efficient gear indication sensor can

be installed, which can show the gear of the motorcycle in which the engine is running.

15

Appendix – 1

SEMINAR PRESENTATION SLIDES

16

17

18

19

20

REFERENCES

[1] Fahad Ahmed, Haider Ali Zaidi, Syed Waqar Hussain Rizvi: “Electronic Automatic Gear

Shifting System for a Motorcycle “ ,Wireless Network , information Processing and System,

(2008) 3-10.

[2] “Wheel speed sensors in motor vehicles Function, diagnosis, troubleshooting” (Chapter 1) 2-

11.

[3] Kurt e. Petersen, Anne Shartel, and Norman f. Raley: “Micromechanical accelerometer

integrated with mos detection circuitry”, January (1998) 23-27

[4] W.K.lai, M.F.Rahmath and N.Abdul Wahab: “modeling and controller design of pneumatic

actuator system with control valve” international journal of smart sensing and intelligent

systems June (2012) 624-644.

[5] W.Torbacki: “numerical strength and fatigue analysis in application to hydraulic actuator”

journal of achievements in materials and manufacturing engineering December (2007)65-68.