For the combustion of fresh charge of mixture it must be burn in engine cylinder.This is done with the help of spark plug.A spark is produced in spark plug by ignition system.The details about various ignition system will be covered in this post.
01) Coil Ignition System:-
This ignition system consists of a 6 or 12 volt battery,resistance,ignition switch,ammeter,high tension coil,contact breaker,condenser,high tension distributor and spark plug.
The high tension coil consists of a Water proof casing containing a few turns of heavy wire forming a primary winding surrounded by about 20000 turns of fine wire forming secondary winding,both the windings being wound over a laminated soft iron core and insulated from each other.One end of secondary winding is earthed while the other end connected through a heavily insulated wire into the centre of the distributor cap.
A carbon contact carries the current to the rotor arm,made of bronze which revolves and distributes the current to the various cylinders through spark plug leads.Thus the rotor arm connects the proper spark plug to the secondary winding at the required moment.
As the flow of current through the primary winding is stopped by the contact breaker,a very high voltage( near about 8000 to 10000 volts) is induced in the secondary winding.This voltage is supplied through the high tension distributor to the appropriate spark plug gap there by producing a spark.The high tension distributor and the contact breaker,are placed in one body.
The condenser in the primary circuit prevents sparking at the contact breaker points.It also increase the electromotive force in the secondary at break while it further decrease the electromotive force in the secondary at make thus giving a high voltage unidirectional current.
The contact breaker consists of a cam with a number of lobes on it,a fixed post holding one contact while other contacts is mounted on a movable arm.The material used for contacts are platinum and tungsten.
The contact breaker points are opened only 3 to 3.5 millimeter apart.The high tension distributor is prevents the serious trouble that are likely to be developed in the high tension coil either when the current flows due to a faulty circuit or when the ignition switch is left in the "On" position,in either case the high tension coil may be heated up giving an inferior performance.
The resistance wire may also act as a fuse breaking the primary circuit thereby avoiding the discharge of the battery.
02) Magneto Ignition System:-
This system consists of a switch,a magneto,contact breaker,condenser,high tension distributor and spark plugs.
The magneto consists of a fixed armature having primary and secondary winding and a rotating magnetic assembly driven from the engine.
The electromotive force induced in the secondary is insufficient to produce a spark.Consequently it is transformed into the high voltage by the contact breaker in the primary circuit.The voltage induced may be more than 10000 volts.
The spark is produced at the correct moment in the proper cylinder with the help of high tension distributor.(As per the action takes place in coil ignition system.)
I hope,this will give you a little knowledge about ignition of your vehicle.what you say?
You may also interested in following.......
How To Draw Valve Timing Diagram For Four Stroke Petrol Engine?
Working Principle Of Simple Carburettor Used In Petrol Engine.
Different Types Of Compensation In Simple Carburettor.