Battery Ignition System is used in automobile to produce spark in the spark plug for the combustion of
fuel in the I.C. engine. Here the main source for the spark generation is the battery. It is mostly used in
light commercial vehicles.
Battery
A battery is used to provide energy for ignition. It is work as storage of energy and charged by dynamo,
which is driven by engine. It converts chemical energy to electric energy. Two types of battery used in
spark ignition system, lead acid battery and alkaline battery. The first one is used in light duty
commercial vehicle and the other one is used in heavy duty commercial vehicle. It is housed in primary
side of ignition coil.
Ignition switch
It is used to turn on and off the ignition system. Battery is connected to the primary winding of
ignition coil by ignition switch and ballast resistor.
Ballast resistor
It is connected in series with primary winding to regulate current in primary winding. It is used to
prevent injury due to overheating of ignition coil. It controls the current passes through primary
winding. It is made by iron. Iron has property of increase electrical resistance rapidly by increase
in temperature at certain limit. This additional resistance resists flowing current which control the
temperature of ignition coil.
Ignition coil
Ignition coil is the main body of battery ignition system. The purpose of ignition coil to step up
the battery voltage (6 or 12) to a high voltage, which is sufficient to produce spark at spark plug.
It consist a magnetic core or soft wire or sheet, and two electrical winding called primary winding
and secondary winding. The primary winding has generally 200-300 turn and the end are
connected to exterior terminal. The secondary has almost 21000 turns of copper wire which is
insulated to withstand with high voltage. It is located inside the primary winding and its one end
connected to secondary winding and other end is grounded either to primary winding or to the
metal case. This entire unit is enclosed in a metal container which makes it a compact unit.
Contact breaker
This is a mechanical device making and braking the primary circuit to ignition coil. When the
points are closed current flow in ignition coil and when it open, flow of current stopped.
Distributor
Distributor is used in multi cylinder engine to regulate spark in each spark plug at correct sequence.
It distribute ignition surge in individual spark plug in correct sequence. There are two types of
distributor. One is known as carbon brush type and the other one is gap type. In carbon brush type
carbon brush carried by the rotor arm sliding over the metallic segment embedded into the
distributor cap or molded insulating material. This makes electric connection or secondary winding
with spark plug. In gap type distributor electrode of rotor arm pass close to but does not make
contact with the distributor cap. So there is no wear of electrode.