Types of Ignition System
Types of Ignition System :- Mostly used in S.I. systems and based on electricity, the ignition system is used to light mixture of air and fuel. This ignition is generated to start the combustion process in the combustion chamber. Hence we can say that, this system converts chemical energy into heat through the spark generated in the ignition system causing the fuel-air mixture to burn.
Function of Ignition System
- To create high voltage electric spark in the combustion chamber at correct timing in order to burn the air fuel mixture.
- This creates a potential difference of ~25kV across the spark plugs.
- It provides high spark voltage to each spark plug in the correct order.
- It adjusts the spark timing with speed and load of the vehicle.
- The spark is adjusted so it can be generated when piston is near the top dead Centre.
Components of Ignition System
1. . Battery: ( Components of Ignition Systems )
The battery is used to provide current to the ignition system. This in turn energizes the ignition coil. Generally, the voltage of the battery is 6V or 12V.
2. Ignition Switch: ( Components of Ignition Systems )
It is used to turn ON or OFF the engine. One end of the switch is connected with the Primary Winding of Ignition Coil, and another end is connected with the Battery.
3. Ignition Coil: ( Components of Ignition Systems )
It is the main part of Ignition System. The main purpose of it is to step up battery voltage so that it is sufficient for generates the spark. It is working as a step-up transformer, and has two windings, one is primary which have a lesser turn, and the other one is secondary which have a higher number of turn.
4. Distributor: ( Components of Ignition Systems )
It is used in the multi-cylinder engine, and its purpose is to regulate spark in each spark plug at the correct sequence depending on firing order.
5. Spark Plug: ( Components of Ignition Systems )
Spark Plug is another important part of Ignition system. Here the actual Spark is generated for the combustion of Fuel or Charge. If there is more than one spark plug exists then each one is connected separately with the distributor and gives the spark in the sequence.
Types of Ignition System
They are basically classified on the method of current supplied to the primary winding
- Battery ignition system
- Magneto ignition system
1. Battery Ignition System
Principle:-It is based on the principle of electromagnetic induction. Mostly used in cars and trucks. In this system a battery of 12 volts is generally employed.
Construction of Battery ignition System
It consists of two circuits-Primary and secondary
The first circuit comprises of-
- Primary winding of the ignition coil
- Contact breaker from the primary circuit
The second circuit comprises of-
- Winding of the ignition coil
- Spark plugs forms the secondary circuits.
The value of the voltage depends upon the number of turns in each coil. The high voltage 10,000 to 20,000 volts then passes to a distributor.
Working of Battery Ignition System
After turning the switch on In battery ignition system the current flows to-
- First the primary circuit through ballast register
- Secondly to primary winding
- Lastly to contact breaker
The flowing current induces a magnetic field around the primary winding. The contact breaker opens the current flowing through the primary winding and this result in significant current fall, at a particular point. This sudden fall of current generates very high voltage around 300 V in the primary winding section.
This high voltage charges the capacitor completely. The capacitor starts delivering the current towards the battery. This induces reverse flowing of the current. Also there is an already induced magnetic field in the primary winding. It overall results in a very high voltage of 15000 V to 30000 V is generated in the secondary winding.
This high voltage current is then transferred to the distributor. The distributor cap has metallic segments embedded on it. So when it starts rotating then at a certain stage it opens the contact breaker point which allows the high voltage current to transfer to the spark plugs through the metallic segments. So when the high voltage current reaches the spark plug then its generates a high intensity of spark inside the engine cylinder, which allows the combustion fuel to burn.
Advantages of Battery Ignition System
- Initial cost is very less.
- Gives a good spark at staring at low engine speed.
- The driving of high-speed engine is simpler as compared to magneto system.
- No maintenance required. Only battery replacement required.
- Due to no moving parts to generate the current important items can be placed to a reachable position.
Disadvantages of Battery Ignition System
- System becomes bulky due to heavy battery
- In case of low battery the engine doesn’t start.
- Timely maintenance and replacement of the battery is a must.
- Exposure of the breaker point to mechanical and electrical wear is harmful for the engine.
2. Magneto Ignition System
Principle: – Principle is same as the battery ignition system. In this, no battery is required, as the magneto acts as its own generator.
Construction of Magneto Ignition System
It consists of either rotating magnets in fixed coils, or rotating coils in fixed magnets. Magneto produces the current. Flow of the current takes place in the induction coil.
Working of Magneto Ignition System
The working of Magneto ignition system is same as the battery ignition system only the method of supply of primary circuit current is different. In this system magnet and fixed coil (armature) is used which is driven by crank of engine and produces current for primary circuit.
Other steps are same as the battery ignition system.
Advantages of Magneto Ignition System
- No need of battery. It is self energizing system.
- It is compact.
- Good spark at high speed.
- Requires less maintenance due to absence of battery.
Disadvantages of Magneto Ignition System
- At starting spark is poor.
- Spark timing adjustments affects spark voltage.
- High voltage spark at high speed can harm the electrode.