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ignition system, in a gasoline engine, means employed for producing an electric spark to ignite the fuel–air mixture; the burning of this mixture in the cylinders produces the motive force.

Ignition involves four basic and sequential functions: the provision of low-voltage electricity, amplification of the voltage to a high level, distribution of a high-voltage electrical current pulse to each of the combustion chambers and, finally, discharge in the form of sparks.

Currently, we recognize four types of ignition systems used in most cars and trucks: conventional breaker-point ignitions, high energy (electronic) ignitions, distributor-less (waste spark) ignition and coil-on-plug ignitions.

The purpose of the ignition system is to generate a very high voltage from the car's 12-volt battery and send it to each spark plug in turn, igniting the fuel-air mixture in the engine's combustion chambers. The ignition coil is the component responsible for producing this high voltage.

Components of a Conventional Ignition System The key activates the ignition switch. The battery provides a current which travels to the ignition coil. The ignition coil magnifies this current. A spark is created from the generated electrical energy. The spark is distributed to each of the spark plugs by the distributor.

There are three basic types of automotive ignition systems: distributor-based, distributor-less, and coil-on-plug (COP). Early ignition systems used fully mechanical distributors to deliver the spark at the right time.

Once the ignition switch is prompted by key or the push of a button, it activates the voltage from the battery to the ignition coil to produce the engine spark. The engine spark from the coil or coils is directed to the spark plugs to ignite the fuel to make the vehicle run.