How Do Spark Plugs Work?

Spark plugs are quintessential components in your ignition system, thus knowing how it works is essential if you want to make a good choice. This article discusses in detail all that you need to know about how spark plugs work.

Construction Of Spark Plugs

Spark plugs are precision piece of documents, and they may not be as simple as they seem to you as there are several components that makes up the construction of spark plugs, namely:

Corrugation

It’s a product of aluminum oxide ceramic, its primary function is to give extra protection against secondary voltage or spark over. In addition, corrugation also play an important role in affirming the grip of the rubber spark plug boot against the spark body.

Ceramic Insulators

The insulators in spark plugs is a product of aluminum oxide ceramics, its main purpose is to give the spark plug an extraordinary dielectric strength, good shock resistance, and high thermal conductivity. In other words, they’re the cause for dielectric barrier that helps to generate high-voltage pulses that are necessary for igniting the air-fuel mixture and they also help to give mechanical support to the center electrode.

Hex

Hexagon in spark plugs is what determine the socket required for installation. Furthermore, the hexagon is what gives the contact point for a socket wrench, it is uniform in the industry (5/8 “(16mm) and 13/16), and are generally related to the spark plug thread size.

Shell

The shell of a spark plug is the outer part that surrounds the insulator, installs the spark plug in the engine, and supports the insulator. You’ll find a ground electrode at the bottom for current to flow through the engine itself to the center electrode over the gap. In addition, the shells get forged for actual tolerance through a special extrusion process.

Plating

Plating is a component of spark plugs that is necessary for high durability, corrosion resistance, and rust resistance. The hexagon is often machined in the shell so that you are able to use a socket wrench to install or remove the plug.

Gasket

Not all, but some types of spark plugs utilize gaskets. The reason for gasket in some spark plugs is to make the housing and the engine fit tight to each other, to give a smooth surface for sealing process, and to maintain artighness for the combustion chamber. Although, there’s a process that the manufacturer must consider for the tightening and the right margin to be secured.

Threads

You only roll threads in spark plugs, not cut. This is because the rolling process meets the SAE standard as well as the International Standards Association requirements.

Ground Or Slide Electrode

Ground electrodes in spark plugs minimize the quench effect, and increase the ignition performance. Furthermore, they vary in shape and configuration, they are a product of nickel alloy steel, and they’re shaped in a way that the electrode tip is cut to fine tune the tapered shape. In conclusion, it’s important that the ground electrode resist chemical erosion and spark erosion, and both must be under massive and extreme pressure.

Central Electrode

Central electrode in spark plugs connects to the spark plugs terminal by internal wire. The tip features copper, chromium, nickel or other precious materials. The high voltage is carried by the metal all over the spark plug for it to spark when it goes through the small gap between the central electrode and the side electrode.

Spark Plug Electrode Gap

The spark electrode simply means the distance between the tip of the spark plug and the center electrode. In addition, it’s a product of special alloy that is resistant to both spark erosion and chemical corrosion.

Insulator Nose

Insulator nose spark plugs vary in sizes and shapes, this is because the insulator must have the capability of shedding carbon, and depositing oil and fuel at low speeds. In conclusion, the insulator nose is in a cool state during higher level speed to minimize temperature and electrode corrosion.

The Roles Spark Plugs Play In Your Engine

Spark plugs are what supply the spark that are necessary to ignite the mixture of air/fuel in your engine. They  also create the explosion that gives your engine the ability to generate power. Furthermore, spark plugs generate an electricity arc through the two leads that are not in contact, but are close to each other so that electricity can jump the gap between them.

Causes Of Overheating In Spark Plugs

When your spark plug overheats frequently, it will fail prematurely. However, here are some factors that can cause overheating to your spark plugs, you should consider avoiding them:

Hot spark plug heat range

Pre-ignition and overheat will occur in your spark plugs if the heat range exceeds 500 – 800 degrees celsius.

Insufficient coolant

When there is inadequate coolant, there’ll be high temperature in your engine surface, thus leading to spark plug overheating.

Higher Fuel Mixture Temperature

 Sometimes you might want to use richer fuel mixture for best performance in your engine, but the richer fuel might burn at higher temperatures which could lead to excessive heating of your engine spark plug.

Engine Oil Leak

Spark plugs in your engine will overheat if there is insufficient oil in your engine due to worn piston rings or cylinder walls.

Excessive Turbo Pressure

Turbo is one engine part that allows you to adjust and change the pressures of the turbo base on the level of performance you want to attain. If you apply too much pressure, it will initiate excessive heat, thus leading to huge overheating in your engine spark plug.

Bad Fuel Quality

 Bad fuel quality does not just damage some particular components of your engine, but it will cause your vehicle to also overheat thus damaging your spark plug.

Inadequate Plug Tightening

Make sure you always set up your engine’s spark plugs correctly, because if you did not, there’s possibilities of additives in your engine spark plugs.

Over-Advanced Ignition Timing

This will not only reduce the power of your engine, but will also cause detonation, and will make your engine’s spark plugs overheat.

Low Spark Plug Rating

This will cause overheating to your spark plug because, when the spark plug heat rating is too low, there’ll be a massive rise in the temperature of your spark plug and this will prompt abnormal combustion.

Factors Affecting Heat Rate In Spark Plugs

Here are the basic structural factors that affects the heat range in spark plugs:

• Nitric oxide
• Metanol
• Air/fuel mixture modification
• High speed driving
• High ignition driving
• High comprehension ratio
• Supercharging/turbocharging
• Surface area
• Length of insulator nose
• Insulator tip positioning
• Center electrode material
• Gasoline quality
• Spark advancement
• Engine condition
• Humidity

Spark Plug Voltage Rise

Spark plug voltage rises when electricity flows from the coil, there’s a voltage difference that develops between the center electrode and ground electrode on the spark plug. In addition, the spark plug cannot fire immediately because of the gap in-between the spark plug and the air/fuel mixture.  In other words, the spark plug only fires when it gets to exact 20,000 volts which is known as the breach stage.

Spark Plug Thermal Performance

This refers to the firing end of your spark plug that you must keep low to suspend pre-ignition. But it must be high enough to suspend fouling, this is usually determined by the heat range selected.

What Is The Purpose Of The Resistor In The Spark Plug?

The main purpose of the resistor in spark plugs is to filter out the generated noise that may affect other electrical components.

Spark And Ignition

Applications Of Spark Plugs

The use of spark plugs cannot be underestimated in internal combustion engines, this is because they are necessary components for initiating combustions. To give you a good sense of the first sentence, below are some examples where these precious components are applicable:

Automotive Engines: Spark plugs are integral parts in automotive engines for facilitating the mixture of air/fuel mixture in the combustion chamber in the internal combustion engine.

Marine Engines: In marine engines, high voltage capacity is taken in by the spark plug at one end and a spark will ignite at the other end. This process is necessary to create combustion that powers your boat.

Aircraft Engines: Spark plugs are necessary to create combustion and powering aviation propulsion systems. In addition, it delivers electric current through the ignition system to the combustion chamber, the current is what ignites the fuel mixture in the internal combustion engine.

Small Engines: Small engines like chainsaws, generators, lawnmowers, and other small engines depend on spark plugs.

How To Maintain Your Spark Plugs

There’s spark plug long life assurance if you properly maintain your spark plugs. Below are some guide that can help you:

• Use a compressed airgun to clean the debris around the spark plugs before removing it.
• Check if there is crack in the porcelain, and make sure the center electrode is straight and in-line with the central electrode.
• Spray cavity around the center electrode.
• Minimize gailing the thread in the cylinder head by coating the thread with antesize compound.
• Coat with dielectric compound.
• Always check the spark plug gap and make sure the gap is around 0.020 and 0.060
• Tighten your spark plugs according to your.
• Avoid carbon build up.
• Prevent oil leakage in your combustion chamber.
• Avoid constant overheating.

FAQ

How Do I Know I Need To Replace My Spark Plugs?

Here are some common signs that you need to replace your spark plugs; engine misfires, slow acceleration, rough idling, poor gas mileage, and trouble starting your engine.

Why Do Spark Plugs Wear Out?

Spark plugs wear out because of the repeated overheating of the spark plug tip.

Conclusion

In conclusion you cannot underestimate the functioning of spark plugs in gasoline-powered engines, because without it there’s no way your engine can ignite power that is necessary for proper running of your engines.