- An ignitor is a device that provides ignition for early internal combustion engines, but is typically not used on engines today. An ignitor is an early version of the spark plug found in contemporary internal combustion engines, but has one major difference. Spark plugs use a considerable electrical charge to create the spark necessary to ignite fuel. Ignitors, on the other hand, use extremely low voltage--only a few volts per spark.
- Ignitors that are used in small engines are simple mechanisms. They are merely comprised of two electrical contacts, which are opened and closed to create a spark. These contacts are connected to a source of electricity. This source could either be a battery, or a magneto, and an electrical coil.
- When the ignitor is connected to a battery as an electricity source, it has an extra spring. The spring holds the contacts open during ignition, until a spark is produced and the engine fires. This prevents the battery from running down, due to the fact that these types of engines were not very reliable, and often did not fire on the first try.
- A magneto is a permanent magnet that is attached to the engine flywheel, and passes over the coil to produce an electrical charge. When a magneto is used, the contacts remain closed until a spark is needed. It is unnecessary to hold the contacts open to conserve electricity, due to the fact that the electricity needed for the spark is created by the magneto.
- The ignitor and source of the electricity are mounted together in the engine. During the ignition process, the electricity passes through the contacts, until the piston of the engine reaches the center of the compression cycle. This opens the contacts, forcing the current to flow through the air between them. The arc of current in the air creates a spark. The spark ignites the fuel in the combustion chamber, powering the engine.
