Page 243 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

resulting in a weak spark. More carbon accumulates in the area left below the spark plug tip, which absorbs the
heat of the spark

2 Battery
The battery is the main source of electric current in the ignition process. It generates low tension current for this
system. In petrol engine, electric current is used to burn the compressed mixture of air and petrol through spark
plug. Generally, 6 or 12 volt batteries are used in the ignition system.
3 Ignition Coil
This coil plays a main role in converting the low tension current of the battery into high tension current. It works
like a ‘step-up’ transformer. With its help, the current of 6 volt or 12-volt battery can be increased to 20,000 volts.

This ignition coil has primary and secondary windings of insulated copper wires on an iron core. The circuits of
primary and secondary winding are shown in the figure below.
The primary winding is down to the thick copper wires on the same shaft iron core and has fewer turns, about
200-300. On the contrary, above this winding there is a secondary winding, which has more turns of thin wire,
which are about 21000.
Primary winding, which is the CB of the battery and distributor. (contact breaker) point, there are two low tension
terminals on the ignition coil.

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CITS : Automotive - Mechanic Diesel - Lesson 71 - 75