When the air fuel mixture introduce to the I.C. engine it expand in the cylinder as the piston move from top dead center(TDC) to bottom dead center(BDC). operation of the I.C engine depend upon the burning and expansion of the air fuel mixture within the cylinder.Ignition system is used to ignite the air fuel mixture for complete combustion of the fuel.Ignition of the must be occur at the right time to produce the maximum energy during the expansion of hot gases in combustion chamber.
Ignition system is a group of component which delivers the sparks to the sparks plug at the right time to fire the air fuel mixture.
- In 2 stroke engine , spark plug produces spark in cylinder for every revolution of the piston.
- In 4 stroke engine, spark plug produces spark in cylinder for every alternate revolution of the piston.
Ignition system transfer low voltage to high voltage and this voltage is used to proper spark at the right tome.
Now a days Lean mixture are used in the vehicle to reduce the pollution level in the environment.
lean mixture is a mixture of air fuel having the air ratio is more than the fuel.such mixture require higher voltage ignition system to ignite the mixture.
Types of ignition system
- Point ignition system:- Breaker points are used to interrupt the primary current in circuit.
E.g- Battery ignition system, magneto ignition system
2.solid state ignition system: This system is used in any engine which uses electronic device like diode. in this system primary current stopped and restarted.
Battery Ignition System
Most of the I.C engines uses battery ignition system. in this system a 12 volt battery supplies the electric current to the coil and the ignition coil is an electrical transformer which changes low voltage to high voltage current which produces enough current at the right time to fire the mixture.two coils are used in this system ,primary coil and ignition coil . Ignition coil is consist of two winding , primary winding of 150 to 200 turns and the secondary winding of 10000 to 20,000 turns. This helps to transform the low voltage current to high voltage current.
Primary circuit completed when the contact points are closed and primary current flow through the primary winding. This current induced the EMF in the secondary coil.when the breaker break yhe path of the current flow and it produces high voltage.Hence the ignition coil store the energy in the form of magnetic field and deliver to spark plug at the right time whenever it is require .
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Advantages
- There is no moving part.
- Produces better sparks at low speed of the engine.
- Distributor set is simple
- Cost is less
Disadvantage
- If battery exhausted , engine will not start
- when the speed of engine increases , sparking voltages gets decreases.
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