Skip the auto shop - Our mechanics make house calls

Q: How Do Spark Plugs Work in an Engine?

asked by on

How do spark plugs work in an engine?

A: Spark plugs are used to ignite the air/fuel...

Spark plugs are used to ignite the air/fuel mixture in the combustion chambers of every internal combustion engine.

To accomplish this, spark plugs have two electrodes between which a high voltage spark will jump. One electrode is located in the center of the plug and one electrode is attached to the side of the plug.

The high voltage comes from an ignition coil and contains anywhere from 5,000 volts to 40,000 volts. The high voltage is necessary to overcome the air turbulence, compression pressure, and the air gap of the spark plug during the combustion cycle. The spark jumps from one electrode to the other. This spark ignites the air/fuel mixture in the combustion chamber. The combustion continues until all the fuel has been converted into heat and increased cylinder pressure. This is what creates the power inside of an engine.

Each spark plug fires one time for every two revolutions of the engine crankshaft.

If your vehicle is down on power or is getting less fuel economy, a fresh set of spark plugs may be in order. If you need help with this, schedule a visit with a certified technician who can check out the situation and replace your spark plugs if necessary.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Truck stutters when climbing long inclines

The motor is probably shot. It sounds as though the head gasket is blown, allowing coolant into the engine; when that happens, all you can do is replace the engine or rebuild it. I would recommend taking it to a...

Q: What Wears Out Engine Spark Plugs?

Spark plugs are used to ignite the air/fuel mixture in the combustion chambers of every engine. The plugs are subjected to extreme heat, combustion pressures, and vibration. These are just some of the factors that contribute to spark plug wear....

Q: Car does not start

Hi! First, we will need to determine which no-start situation has occurred. If you turn the key and nothing happens, there is a fault in the starting/charging system. An engine that turns over but will not start, often has issues...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.