Hey Readers, Let’s see what is the differences between fuel injector and spark plug, and why we need to use them?

Let’s start with the introduction of Fuel Injector and Spark Plug.

What is a Spark Plug?

Spark Plug is a Mechanical component which is located at the top of the engine cylinder.

The main function of a spark plug is to produce the Spark in the combustion Chamber for ignition of charge inside the engine cylinder

Here are some important points of the spark plug which you should know:

This device is located at top of the engine cylinder.

The proper location of the spark plug provides Correct timing for Ignition.

The main requirement of Spark Plug is, it must have High Resistance and must have a proper gap between the two electrodes.

This Gap is usually between 0.6mm to 1mm.

In automobiles, there are different types of spark plugs are commonly used: Detachable and Non-detachable type and Hot and Cold type and Special type of spark plugs.

spark plug hot and cold diagram
User:Emmanuel.boutet [CC BY-SA 3.0 (]

What is Fuel Injector?

The fuel injector is fitted inside the diesel engine. As you know in compression ignition engine the pressurized fuel sprayed inside engine cylinder and due to the high temperature inside the cylinder the vapourised fuel burned and then engine produced power stroke, so to control the amount of fuel and also the timing of fuel to sprayed inside the cylinder is maintained by the fuel injector.

Here is an animated overview of a fuel injector.

Fuel injector diagram
By WikipedianProlific, CC BY-SA 3.0,

Difference Between the Spark plug and Fuel injector:

Primarily function of both of these Mechanical components is to Ignite the fuel inside the engine cylinder.

Here is the difference between the spark plug and fuel injector:

Spark plug Fuel Injector
The spark plug is fitted inside the Petrol Engine. (In a Petrol engine, the air-fuel mixture is sent into the engine cylinder and the mixture is ignited by the spark generated by the spark plug).The fuel injector is fitted inside the diesel engine. (In Diesel engines don’t require any spark plug and the required heat to, Ignite the fuel is generated due to compression of air).
The component generates the spark with the help of DC current.The devices compressed the diesel and after that, it burns and then the engine works.
Spark plug used is SI Engine (Spark Ignition Engine).Fuel Injector is used in CI Engine (Compression IgnitionEngine)
The spark plug is used to generate a spark in the compressed air-fuel mixture.The fuel injector is used to regulate the fuels flowing into the engine cylinder.

So these are some basic differences between the spark plug and Fuel Injector, I hope I am able to explain my knowledge perfectly, please share your thoughts on the comment section, and also don’t forget to share this article on your favorite social handle and give chance to other to read this article. And below is your PDF downloadable link.

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About the Author

Amrit Kumar

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Amrit is a Co-founder of Learn Mechanical Portal (Previously owned ""). He completed his diploma in Mechanical Engineering from Acharya Polytechnic Bangalore and also completed his B-Tech from Delhi.

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