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In gasoline engine: Spark plugs
…it is essential that the spark gap be as specified for the particular engine. Gauges are available to aid in making this adjustment by bending the ground electrode as required. Manufacturers specify gaps ranging from 0.508 to 1.016 mm between the centre electrode and the ground electrode. If the plug…
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spark plug

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internal-combustion engine: four-stroke cycle

spark plug

electronic device

Also known as: sparking plug

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Also called:: Sparking Plug

Key People:: Robert Bosch

Related Topics:: ignition system; spark gap

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spark plug, device that fits into the cylinder head of an internal-combustion engine and carries two electrodes separated by an air gap, across which current from a high-tension ignition system discharges, to form a spark for igniting the air–fuel mixture. The electrodes must be able to resist high temperatures, and the insulator separating them must withstand high temperatures and also an electric stress up to several thousand volts. Spark-gap length affects the energy of the spark, and the shape of the insulator affects the temperature of operation. When too cool, operation leads to carbonization and short-circuiting of the gap; when too hot, there may be preignition.

This article was most recently revised and updated by Amy Tikkanen.

spark gap

Learn about this topic in these articles:

gasoline engines

spark plug