Battery Ignition System Working Principle and Parts Explanation

Nowadays the battery ignition system is rarely found, besides the old-typed ignition system is also considered less efficient.

But the electronic ignition system that is widely applied now is the result of the development of the battery ignition system. So we also have to learn how the battery ignition system work, because it is the basis of the car ignition system in the current era.

If you are looking for a complete explanation of the battery ignition system, you are lucky because in this article we will discuss it in detail but easy to understand.

Battery Ignition System Definition

A battery ignition system is an ignition system that uses batteries as the main energy. We know that the function of ignition system is to run combustion inside the engine, to do that, the system is need to provide a spark.

Sparks are obtained from changes in electrical energy, so the spark plug actually comes from electricity in the battery.

Then how can a 12 volt DC battery comes into a spark on a spark plug?

Simply put, this spark arises due to the very high voltage on the spark plug. While in high voltage electricity, the power is also very high so that we can see the sparking electrons on the spark plug gap that only 0.8 mm.

More details will be explained below.

Battery Ignition System Parts and Function

There are several main components in the battery ignition system, among others;

Battery, it is a source of energy for the ignition system.
Ignition switch, to activate or deactivate the ignition system manually (via ignition key).
Ignition coil, is a step up transformer to increase the battery voltage.
Contact breaker, is a mechanism to cut the primary winding of the ignition coil so that the voltage on the secondary winding can rise significantly.
Capacitor, an electronic component to prevent electrical sparks in the contact breaker.
Distributor, used to divide the secondary winding from the ignition coil to each spark plug, you can only see the distributor on car engine (more than 1-cylinder engine)
Spark plug, is an actuator that can convert high-voltage electrical energy into sparks.
High voltage wire, there are two types of wires in the ignition system namely standard cable (12 V) and high voltage cable with a larger diameter to be able to conduct electricity with voltages up to 20 KV.

Battery Ignition System Working Principle

To understand how the battery ignition system works, you need to understand two main parts. Namely;

Ignition coil and contact breaker.

As explained above, the ignition coil is a step up transformer that can increase the voltage. But the ignition coil design is not like a transformer in general.

Here, the primary winding is located on the outside while the secondary winding is located inside the primary winding.

Then how the ignition coil is able to increase the voltage of 12 volts to 20 KV?

The answer is because of the magnetic field, secondary winding has a greater number of turns so that the output voltage is greater than the input voltage. But why does it reach 20 KV?

That is because the primary coil magnetic field is not static but moves from outside to inside, to move the magnetic field of primary winding, the current in the primary winding must be cut suddenly.

When the current still flows in the primary winding, a magnetic field is formed on the outside of the ignition coil. When the current in the primary winding is cut off, the previously formed magnetic field will move inward towards the secondary winding before finally disappearing.

The induction will suddenly increase the secondary winding voltage so that it can be converted into sparks.

This is where the contact breaker job, this serves to cut off the primary current according to ignition timming.

After understanding how the ignition coil works, you can see the diagram below.

From the diagram above, there are two schemes

1. Primary schema

As explained above, this primary scheme serves to induce the ignition coil. This scheme, if written down, starts from the battery - ignition switch - primary winding of ignition coil - contact breaker - capacitor - ground.

2. Secondary scheme

The secondary scheme is a series to pass high voltage electricity to the spark plugs to create sparks.

This is from the battery - ignition switch - secondary winding of ignition coil - distributor - spark plug - ground.

How can the contact breaker cut off the primary current according to engine ignition timming?

 It just about the mechanism, we know there is a valve mechanism where the engine valves are always open and closed at the right time. That's because there is a connection between the crankshaft and camshaft.

The contact breaker mechanism consists of a cam breaker, and a breaker lever.

Cam breaker is connected to the camshaft which is also indirectly connected to the crankshaft. When the cam touches the breaker lever, the contact point will be raised and that causes the primary current to be cut off.

Meanwhile, when the cam shifts, the contact point is back attached so that the primary current is re-connected.

Cam is designed to always touch the breaker lever when the piston is at TDC at the combustion step. So that induction also only occurs in ignition timming.

The engine RPM is directly proportional to the ignition interval because the higher the engine RPM, the faster the cam breaker rotates and it causes the faster induction interval.