Design And Construction Of An Electronic Ignition System (Transistorized)

ABSTRACT

This work is a transistorized electronic ignition system. An electrical system for use with an ignition system of the type including an ignition coil and breaker points. The electrical system provides for low current through the breaker points to minimize wear and corrosion of the breaker points, provides a high primary winding current at saturation of the primary winding and of the transistors of the electrical system to provide a strong spark, and has a minimum of components. The system includes first and second compound-connected transistors with the base of the second transistor being connected to the emitter of the first transistor and the collectors of said transistors being connected to ground potential. A voltage dividing circuit is adapted to be connected in series with the breaker points of a distributor between the emitter of the second transistor and the breaker points. The base of the first transistor is connected to a predetermined point in the voltage dividing circuit; and the emitter and collector of the second transistor are adapted to be connected in series with the primary winding of an ignition coil and a source of electric potential.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE PROJECT
• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• LIMITATION OF THE PROJECT
• METHODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF IGNITION SYSTEM
• REVIEW OF BASIC IGNITION DESIGNS
• IGNITION SYSTEM TYPES
• TYPES OF ELECTRONIC IGNITION SYSTEM
• ADVANTAGES OF ELECTRONIC IGNITION SYSTEM

CHAPTER THREE

METHODOLOGY

• SYSTEM BLOCK DIAGRAM
• SYSTEM CIRCUIT DIAGRAM
• DESCRIPTION SYSTEM PARTS
• CIRCUIT DESCRIPTION
• SYSTEM OPERATION

CHAPTER FOUR

4.0      RESULT AND DISCUSSION

4.1      APPLICATIONS OF ELECTRONIC IGNITION SYSTEM

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                          INTRODUCTION

1.1                            BACKGROUND OF THE STUDY

The ignition system’s function is to initiate combustion in the flammable air-fuel mixture by igniting it at precisely the right moment. In the spark-ignition (Otto) engine, this is achieved with an electrical spark, i.e. an arc discharge between the spark plug’s electrodes. Consistently reliable ignition under all circumstances is essential for ensuring fault-free catalytic-converter operation. Misfiring results in damage to or destruction of the catalytic converter due to overheating during afterburning of the uncombusted mixture.

Conventional coil ignition works when the contact breaker closes with the ignition switched on, current from the battery or alternator flows through the ignition coil’s primary winding, generating a powerful magnetic field in which the energy is stored. At the ignition point, the contact breaker interrupts the current, the magnetic field collapses and the high voltage necessary for ignition is induced in the secondary winding. This voltage is fed from terminal 4 to the ignition distributor via a high- tension cable and from there to the individual spark plugs.

Electronic ignition derives its name from the fact that it calculates the ignition point electronically.

The characteristic curves provided by the conventional distributor’s centrifugal and vacuum-advance units are replaced by an optimized electronic ignition map. Mechanical high-tension distribution is retained with EI ignition. Fully electronic distributorless semiconductor ignition (DLI) uses stationary electronically controlled components to replace the mechanical, rotating high-tension distributor.

Electronic ignition systems operate more precisely than mechanical systems, with major benefits originating in the fact that the ignition process can be triggered from the crankshaft instead of from a distributor (distributor drive tolerances are no longer a factor). The limitations which mechanical adjustment mechanisms place upon the performance curve (summation of curves for load and engine speed in a single progression) are also avoided. The number of input variables is also theoretically unlimited, usually allowing extensions in the ignition angle’s adjustment range. The fixed-drive ignition distributor’s limitations regarding the engine’s ignition-voltage requirements and ignition angle adjustment range are such that it has difficulty coping with larger numbers of cylinders; efficient spark distribution cannot always be guaranteed. Corrective measures include dividing the ignition into two circuits (e.g., for 8- and 12-cylinder engines) and static voltage distribution.

Electronic ignition can be combined with electronic fuel-injection (Motronic), knock control, ASR, etc., making it possible to employ sensors and/or signals from other units in more than one system. The main aim of this work is to build an electronic ignition system.

1.2                                   PROBLEM STATEMENT

It was because of the problems discovered in conventional ignition system such as low efficiency, higher fuel consumption and higher risk of fire accident that led to the discovery of electronic ignition system. Electronic ignition system reduces fire rate in the system and increases the efficiency of automobile. Nowadays, almost all automobiles are equipped with electronic ignition system.

1.3                          AIM / OBJECTIVE OF THE STUDY

The main aim of this work is to build an electronics device that produce stronger spark which is required to burn the lean mixture in the combustion chamber. The objectives are:

1. to reduce emissions
2. increase mileage and improve reliability.

• To economize fuel in an automobile

1. To reduce fire accident.
2. To provide an electrical system which is adapted for use in an electrical ignition system and in which a minimum of components are used providing a very reliable circuit.
3. To provide an improved transistorized ignition system which provides a relatively constant output voltage at the secondary winding of an ignition coil through a wide range of engine speeds. to provide a transistorized ignition system which greatly minimizes, if not altogether eliminates, arcing across the breaker points in a distributor of an electrical ignition system used with an internal combustion engine.

• To provide an improved transistorized ignition system which maintains a hot spark across the electrodes of a spark plug by maintaining high current flow through the primary winding of an ignition coil at high engine speeds

1.4                                    SCOPE OF THE STUDY

Ignition control module is an electronic switch that turns the ignition coil’s primary current either ON or OFF. Control unit performs the same operation as that of contact points in conventional type of ignition system. It is a network of transistors, capacitors and other electronic parts contained in a plastic case. Control module can be located on the side of the distributor or inside distributor under the dash board. Control module manages the dwell period on its own. Ignition coil produces high voltage required to make current pass in the gap at spark plugs. Ignition is pulse type transformer capable of producing a short fire of high voltage for beginning combustion. It is composed of two sets of windings namely primary winding (outer winding) and secondary winding (inner winding). Secondary winding are wound in opposite direction of primary winding and the ends are attached to primary windings and high voltage terminals.

1.5                          SIGNIFICANCE OF THE PROJECT

This research work will throw more light on the best techniques for igniting a car system. This study will also be designed to be of immense benefit to all the users of cars.

Finally, it will also serve as a useful piece of information for both producers and users of cars.

1.6                                                        LIMITATION OF THE STUDY

As we all know that no human effort to achieve a set of goals goes without difficulties, certain constraints were encountered in the course of carrying out this project and they are as follows:-

1. Difficulty in information collection: I found it too difficult in laying hands of useful information regarding this work and this course me to visit different libraries and internet for solution.
2. Difficulty in parts gathering: I found it too difficult when gathering electronics parts used for the prototype.

• Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).

Time Constraint:   The researcher will simultaneously engage in this study with other academic work. This consequently will cut down on the time devoted for the research work

1.8                                             RESEARCH METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Test for continuity of components and devices,

• Design of the device was carried out.

1. Studying of various component used in circuit.
2. Construction of the circuit was carried out. The construction of this project includes the placing of components on Vero boards, soldering and connection of components,
3. Finally, the whole device was cased and final test was carried out.

1.9                                     PROJECT ORGANISATION

This project work is basically divided into five (5) chapters:

CHAPTER ONE: Takes on the introduction of the subject matter. If consists of the super significance and definition of terms of the study.

CHAPTER TWO: This is the literature review this entails the works that had been done on this particular topic which was done by other researchers.

CHAPTER THREE: Will talk about the Method that the researcher adopted in getting necessary materials or information that will facilitate the success of the research work.

CHAPTER FOUR: Explain how the researcher was able to analysis and present the data he got for his work in the chapter:

CHAPTER FIVE: Brings everything to conclusion the researcher does his summary and give necessary recommendation where needed.