What are spark plugs? A very common question in automobiles! In this article, we will learn all the basics of the spark plug, its definition, parts, construction, advantages, disadvantages, applications.
Automobile vehicles work on a wide variety of parts. One of the starting operations is initiated from the device known as the spark plug. It generates a spark to start the combustion of the charge inside the combustion chamber.
If you have a bike and repaired it someday, you may have seen the spark plug ones at least. If the vehicle is not starting or having late starting problems, usually the spark plug problems are there.
We will take a little deep dive into spark plugs. Interested in learning more about spark plugs?
Let’s tune in, starting from the history of spark plugs.
In 1860 Étienne Lenoir developed the first combustion engine and used the electric spark plug. Though Edmond Berger also received some credits regarding the invention of the spark plugs.
The Spark plugs looks small but there is more running inside of it. It is basically composed of the shell, insulator, and the central conductor.
The spark plus also kind of seals off the combustion chamber against high pressure and temperatures if the vehicle is used for extensive times.
There are a few parts of a spark plug, are as follows,
The tope part of the spark plug is the terminal. The terminal is connected to the ignition system. Though the exact configuration of the terminal varies according to the manufacturers.
Also, some of the terminals are provided with the threads that is common for motorcycles.
Recently, the cup-styled terminal is introduced they allow the insulator made of ceramic to stay in the confined space.
As the name suggests it is provided for the electric insulations. The main part of the insulator is made of sintered alumina (Al2O3) composition. It is a very hard ceramic material with high di-electric strength.
The old spark plugs were using the mica stacked layers as the insulator tips generally in aircrafts. Later the lead deposits became problem for the mica layers use. Now the spark plugs after the 1930s are using the same sintered alumina as the tip of the insulators. It was made by Siemens in Germany.
As we have already seen the spark plugs also needs to seals off the chamber of engine once its installed. So, the seal is obviously necessary to ensure no leakage because leakage of the fuel mixture can have severe damages.
Just a little bit more about glass seal method. It uses the special mixture of glass powder and copper powder. The mixture is charged into the installation section of the insulator and center shaft and center electrode.
So even in some harsh conditions, the gaps will not occur and good airtightness is achieved.
The metal case or shell sometimes even called as jacket of the spark plug. It has the work of withstanding the torque of the tightening the plug and serves to remove the heat from insulator and it passes on to the cylinder head.
It is housing forming an outer shell it surrounds the insulator and supports the insulator.
The central electrode connected to the terminal through internal wire and a ceramic series resistance it results in reducing emissions of RF noise due to sparking.
It is also known as the ground strap and made from high nickel steel and it welded to the side of the metal shell.
So, these are the parts of the spark plugs. The spark plus combining all the above parts is used in the automobile vehicles. The working is simple and easily understandable.
Now without going into much of a technical detail let’s understand how spark plugs work.
The working principle of spark plugs are captured, as below
Check a very nice ANIMATED VIDEO from saVRee,
Now we have seen the working of the spark plus, there is one important point mention in the spark plug working can you guess? It’s the spark gap. Let’s know more about it.
The spark plug is not directly in contact with the fuel it has some gap known as the spark gap. It can be adjusted by the technician. Different engines may specify some different spark gaps. But generally, the automobiles have spark gap of 0.6 to 1.8 mm.
On the other hand, if the gap is wider it can prevent the fuel even from firing. Also, it may misfire in some cases. So, basically, the spark gap should be kept at the optimum levels so that the engine may achieve its highest possible efficiency and fuel efficiency.
Let’s check out their advantages and disadvantages.
Iridium spark plugs improve fuel economy
The iridium spark plugs will be beneficial for the fuel economy of the vehicle. It has the improved ignition profile which burns the fuel more efficiently.
Less voltage requirements
The electrical currents surges from the spark plugs. But the Iridium spark plugs doesn’t need that much of voltage to produce the power. Because it has small electrode energy saving during start-up phase ensures the driving experience.
More durability with Iridium spark plugs
The iridium has high strength and hence it has more durability compared to other copper and platinum alternatives. For example, if you get copper or platinum instead of iridium you may be getting just 50% of the lifespan of Iridium.
More corrosion resistance
The Iridium metal is the corrosion resistance one. It performs well in the engine compartments because of the corrosion resistance properties.
Stable spark generations even at harsh operating conditions.
You may have already known the application of the spark plugs. The spark plugs are used in all of the petrol vehicles. Like, scooters, motorcycles, cars etc. The fuel is burnt with the help of spark plugs.
As we have seen earlier there are some types of spark plugs according to the material used.
Hence, we have learned the basics of spark plugs along with the definition, working, applications. If you have a question, please let us know.
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