Controlled ignition for premix engines: need and principle

This dossier presents spark ignition for internal combustion engines.

An internal combustion engine consists of one or more cylinders in which combustion takes place. These combustions release the energy contained in the fuel.

There are two types of internal combustion engines:

• compression-ignition engines (diesel): fuel is injected into a volume of highly compressed air. In this case, the high pressure in the combustion chamber causes a significant rise in air temperature: the fuel ignites instantly on contact with the hot air;

• spark-ignition engines (gasoline): the air-fuel mixture is ignited by an electric spark (arc between the spark plug electrodes) which raises the temperature of the mixture above its ignition temperature (initiation of combustion).

Only spark-ignition (gasoline) engines require an ignition system to ignite the fuel.

This first part deals with the need for and principle of ignition. It deals with combustion and engine requirements, as well as the functional characteristics of the ignition system.

A second part deals with ignition technology and describes the history of ignition systems, from the earliest systems to the present day, the operating principle of full electronic ignition, the spark plug, installation characteristics, ignition control and, finally, the electromagnetic compatibility of ignition systems.