Spark plug

Figure 1. Spark plugs from an internal combustion engine. Note the gap on the left side is where the spark actually ignites the gasoline and air mixture.[1]

A spark plug is used as a source of ignition, as the "spark" in its name might imply. It is a key component of internal combustion engines and its primary function is to ignite a fuel/air mixture within the combustion chamber of a car, or other system. Figure 1 shows plugs, the spark travels across the gap on the left side of the spark plug.

The voltage in the ignition system must be high enough to create a spark across the spark plug gap (see figure 2), much like a bolt of lightning traveling from the clouds to the Earth. These voltages can be anywhere from 40 kV to 100 kV, in other words high voltage.[2]

Spark plugs are an important part of gasoline engines, but not a part of diesel engines, since diesel is ignited by the compression of the gas instead.

To learn more about spark plugs, click here.

Figure 2. 4-stroke internal combustion engine. 1:fuel injection, 2:ignition, 3:expansion(work is done), 4:exhaust.[3]


Authors and Editors

Jordan Hanania, Kailyn Stenhouse, Jason Donev
Last updated: September 3, 2015
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