Page 256 - Mechanic Diesel - TT
P. 256
MECHANIC DIESEL - CITS
Importance of testing ignition coil, spark plug, condenser
for proper functioning. Common troubles in Ignition
system
Objectives: At the end of this lesson you shall be able to
• explain Importance of testing ignition coil, spark plug, condenser for proper functioning
• trace Common troubles in Ignition system.
Importance of testing ignition coil, spark plug, condenser for proper functioning
The ignition coil is a type of transformer that sets the voltage in the ignition system. It has a soft iron core,
primary winding and secondary winding. The primary winding has 200-300 turns of thick wire (20 SWG) and the
secondary winding has 15000-20000 turns of thin.
Importance of testing ignition coil because it helps ensure the proper functioning of your vehicle’s ignition system.
A faulty ignition coil can lead to misfires at the time of ignition, rough idle, weak fuel economy, and even prevent
your vehicle from starting. allowing for timely repairs and preventing potential damage to other components in the
ignition system.
Spark Plug
The spark plug produces an electric spark which ignites the air-petrol mixture inside the cylinder. The spark plug
is screwed onto the top of the cylinder.
Construction – The spark plug has three main parts:
1 Center electrode or insulated electrode.
2 Ground electrode or outer electrode.
3 Insulator which keeps the two electrodes apart.
The upper end of the center electrode is connected to the spark plug terminal. To this the high tension cable of
the ignition coil is connected. There is a porcelain insulator around it. The lower half of the insulator is covered
with a metal shell. At the bottom of the shell, there is a ground electrode on one side, which is bent towards the
center electrode.
There is a gap between the two electrodes. Thus both the electrodes remain separated by the insulator. There
is a gasket between the insulator and the shell which prevents leakage of gas under different conditions of
temperature and pressure. There are bangles on the lower part of the shell and the upper part is hexagonal so
that it can be screwed into the cylinder head.
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CITS : Automotive - Mechanic Diesel - Lesson 76 - 79
