What is Battery Ignition System? Construction and operation

Battery Ignition System

Requirement Of An Ignition System

(Battery Ignition System)-The ignition system supplies high voltage surges of current (as high as 30,000 volts) to the spark plug. These surges produce the electric sparks at the spark plug gap that ignite or set fire to the compressed air-fuel mixture in the combustion chamber. The sparking must take place at the correct time at the end of the compression stroke in every cycle of operation.

At high speed or during part throttle operation, the spark is advanced so that it occurs somewhat earlier in the cycle, the mixture thus has sufficient time to burn and delivers its power. The ignition system should function efficiently at the maximum and minimum speed so of the engine. This should be easy to maintain, light and compact. It should not cause any interference.

Types Of Ignition System

There are 2 types of ignition systems used in the petrol engines:

  1. Battery ignition system (or coil ignition system).
  2. Magneto ignition system.

Both ignition systems are based on the principle of mutual electromagnetic induction. The battery ignition system is used in passenger cars and light trucks. In the battery ignition system, the current in the primary winding is supplied by the battery, whereas in the magneto ignition system, the magneto produces and supplies the current in the primary winding.

Battery Ignition System


The figure shows a battery ignition system for a four-cylinder engine. It consists of a battery, ammeter, switch, ignition coil, condenser, contact breaker, distributor and spark plug.

The primary ignition circuit starts at the battery and passes through the switch, ammeter, primary winding, contact breaker points to the ground. A condenser is also connected parallel to the contact breaker points. One end of the condenser is connected to the contact breaker arm and the other end is grounded.

The ignition circuit is not connected electrically to the primary ignition circuit. It starts from the ground and passes through the secondary winding, distributors, a spark plug to the ground.

Battery Ignition System
Battery Ignition System


The ignition coil steps up 6o 12 volts from the battery to the high tension voltage of about 20,000 to 30,000 volts required to jump the spark at the spark plug gap, which ignites the combustible air-fuel mixer in the cylinder. The rotor of the distributor revolves and distributes the current to 1 the four segments which in turn, sends it to the spark plugs.

The purpose of the condenser is to reduce arcing at the breaker points and thereby prolong their life. Because the ignition system is of a four-cylinder engine, the cam of the contact breaker has four lobes. It makes and breaks the contact of the primary circuit four times in every revolution of the cam.

Watch the video below to know how the Battery Ignition System works?

When the ignition switch is on, the current will flow from the battery to the primary winding. It produces a magnetic field in the coil. When the contact points open, the magnetic field collapses and the movement of the magnetic field induces a current in the secondary winding coil Because the secondary winding has many more turns (about 21,000 turms) of fine wire (40 SWG), the voltage increases up to 30,000 volts.

The primary winding consists of 200-300 turns of thick wire (20 SWG). About 15,000 volts are necessary to make the spark jump at a 1 mm gap. The distributor then directs this high voltage to the proper spark plug when it jumps the gap, producing a spark which ignites the combustible mixture in the cylinder.

Spark Plug
Spark Plug

Advantages And Disadvantages


  1. Sparking is good even at low speed.
  2. Starting of the engine is easier.


  1. It occupies more space as compared to the magneto ignition system.
  2. If the battery is discharged, the engine cannot be started.
  3. Complicated wiring.
  4. Sparking is good even at low speed.
  5. Starting of the engine is easier.
Ignition Coil
Ignition Coil 

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Creative Blogger And Automobile Engineer.

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