Page 239 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

MODULE 11 :Ignition System

LESSON 71 - 75: Study about types of conventional ignition

system and its components

Objectives

At the end of this lesson you shall be able to
• explain about conventional ignition system.
• differentiate types of Ignition system
• locate and explain different components of Ignition system.

Components of ignition system

Two types of ignition systems are used for fuel combustion in automobiles – magneto ignition system and battery
ignition system.
1 Battery ignition system
2 Magneto ignition system

3 Electroni ignition system
4 Distributor less ignition system
1 Battery ignition system
Battery ignition systems are used in passenger cars, light trucks and some two-wheelers. This system includes
the following parts

1 Spark Plug 2 Battery 3 Ignition Coil 4 Distributor 5 Ignition Switch 6 Condenser
7 Contact breaker
1 Spark plug
Spark plug plays an important role in generating spark in the ignition process. Through this, the mixture of
compressed air and petrol is burnt in the combustion chamber. It is fitted in such a way that its central and side
electrodes remain in the combustion chamber. Hence when HT reaches the central electrode. (H.T.) current
comes, due to excessive voltage of about 24,000 volts, it jumps over it and goes to the side electrode and after
completing the electrical circuit, a spark is generated between those two electrodes, due to which the mixture
burns.
Some air gap is kept between the central and side electrodes, which is also called spark plug gap. This gap varies
for different engines (from 0.5 to 0.7 mm for trains).

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