What are the main components of a conventional ignition system

Conventional ignition systems are composed of the following: power supply (battery, generator), ignition switch, ignition coil, distributor, spark plugs, and high voltage wires.

Power source: The role of the power source in the ignition system is to provide it with the energy it needs to operate.

Ignition Switch: The ignition switch is used to control the on/off switching of the instrumentation circuits, the primary ignition system circuit, and the starter relay circuit.

Ignition Coil: The main function of the ignition coil is to convert low-voltage direct current into high-voltage direct current.

Distributor: the distributor consists of a breaker, distributor, capacitor and ignition advance regulator. The main role of the distributor is to ignite the engine according to the required ignition time and ignition sequence, the ignition coil generated by the high-voltage power distribution to the corresponding cylinder spark plug.

Spark plug: the high voltage distributed by the distributor is introduced into the combustion chamber to ignite the combustible mixture in the combustion chamber.

High-voltage wire; reliably delivers all levels of voltage in the ignition system.

Principle of operation

The ignition switch is turned on and the engine starts to run. During engine operation, the disconnector cam rotates continuously, causing the disconnector contacts to open and close. When the breaker contacts are closed, the battery current starts from the positive terminal of the battery, and flows back to the negative terminal of the battery through the ignition switch, the primary winding of the ignition coil, the movable contact arm of the breaker, the contacts, and the distributor case lap.

When the contacts of the disconnector are opened by the top of the cam, the primary circuit is cut off, the current in the primary winding of the ignition coil rapidly drops to zero, and the magnetic field around the coil and in the core of the iron is also rapidly attenuated to the point of disappearing, so that an induced voltage is generated in the secondary winding of the ignition coil, called the secondary voltage, which passes through the current is called the secondary current, and the circuit through which the secondary current flows is called the secondary circuit.

After the contacts are disconnected, the higher the rate of decline of the primary current, the greater the rate of change of magnetic flux in the core, the higher the induced voltage in the secondary winding, the easier it is to break through the spark plug gap. When the magnetic flux in the ignition coil core changes, it not only generates high voltage in the secondary winding (mutual inductive voltage), but also generates self-induced voltage and current in the primary winding.

In the moment when the contacts are separated and the primary current drops, the direction of the self-inducted current is the same as that of the original primary current. It will break through the contact gap and produce a strong electric spark between the contacts, which not only makes the contacts oxidize and ablate quickly, affecting the normal operation of the disconnector, but also makes the rate of change of the primary current drop, the voltage induced in the secondary winding decrease, and the spark in the gap of the spark plug becomes weaker, so that it is difficult to ignite the mixture.