Basic ignition

A basic ignition system consists of:

• the battery
• low-tension cables
• the ignition coil
• distributor
• coil high-tension cable
• spark plug cables
• and spark plugs

The ignition system provides high-intensity sparks at the spark plugs, to ignite the fuel charges in the combustion chambers. The sparks must be supplied at the right time, and they must have sufficient energy over a range of conditions to ignite the charges. The energy comes from the battery and alternator, and the voltage is increased by the ignition coil.

The system has two circuits. The primary, or low-tension circuit initiates the spark. The secondary, or high-tension circuit produces the high voltage and distributes it to the spark plugs.

There are three general types of ignition systems:

• Breaker ignition uses contact breaker points in a distributor to initiate the spark.
• Electronic ignition doesn’t need contact points. When a signal is received, triggering occurs through transistors in an ignition module.
• Direct ignition has no distributor and uses coils to supply high-voltage direct to the spark plugs.