Spark Plug: Description and Operation

Spark Plug Construction:

PURPOSE
Ignites the combustion mixture.

LOCATION
Threaded into the cylinder head, at the combustion chamber.

OPERATION
The spark plug provides a path for the high current of the secondary circuit to flow to ground. The only paths for this current are through the ground electrode and center electrode across the spark gap. The spark produced when the current jumps the gap and ignites the air/fuel mixture in the cylinder.

Spark Plug Heat Range:

CONSTRUCTION
The temperature of the spark plug is determined by the length of the insulator and the size of the heatsink area. The longer the insulator is, the smaller the heatsink area will be and this will cause the spark plug to be hotter.