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・Save up to 30%

Get a quote

What others are asking

Q: Car takes 2-3 tries before starting

A few different things can cause the vehicle to have camshaft sensor codes. The most common would be the failure with the camshaft sensor, timing chain damage, improper timing, or a wiring issue. The Check Engine Light should illuminate when...

Q: What are the Different Types of Spark Plugs Available?

Talking about spark plugs is a never-ending discussion. Which ones are best? The answer to that question is somewhat trite, but can still be relevant depending on your vehicle and its intended use. Spark plugs come in two basic categories:...

Q: Starting issues. My car won't start right away after sitting over night or for a few hours.

When you say that it won't start, are you saying that the starter doesn't turn (aka it doesn't crank), or are you stating that the vehicle attempts to start (or turns over) but fails? These are two different issues. The...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.