How Do Fuel Injectors Work? Electrical | Mechanical | Explained

We're an affiliate

We hope you love the products we recommend! Just so you know, we may collect a share of sales or other compensation from the links on this page. Thank you if you use our links, we really appreciate it!

Vehicles have become modern life’s necessity and we cannot imagine today’s life without the presence of vehicles. One has to buy one vehicle or the other in order to survive today. But just buying does not help, the vehicle owner has got a number of responsibilities to fulfill. She/he has to feed the vehicle regularly with fuel and other expensive things in addition to proper care from her/his side. In this article, I will explain how do Fuel Injectors work in detail.

In order to take proper care of her/his vehicle, the owner has to understand how the vehicle actually works. A lot of people know about the working of the vehicle but many of them do not know about the fuel injectors- their working and how fuel is supplied to the vehicle.



Fuel injectors are there to supply the required amount of fuel to the vehicles so that the perfect combustion can take place in order to provide the vehicle the power it needs to work. If the engine gets a little more fuel than required, it may get choked and if it gets lesser than what it needs, it may not even start working at all. So, the perfect quantity of the fuel-air mixture is really important.

What Is A Fuel Injector?

A fuel injector is basically the nozzle and valve through which fuel is sprayed into a combustion chamber. It simply works electronically. Usually, it is fixed at some angle so that it sprays the actually needed amount of fuel to the vehicle. Just the perfect fuel-air mixture will not work as long as the angle at which the fuel injector is placed, the pressure at which it supplies fuel in the combustion chamber and the spray pattern is not perfect.

Also Read:  Why Is My Turn Signal Not Flashing On One Side?

Different types of fuel injectors are used in the petrol and diesel engines, petrol engines use a mechanism which is not as direct as the one used by the diesel engines. Let us learn more about how do fuel injectors work.

How Do Fuel Injectors Work?

The ECU (Electronic Control Unit ) or springs control the fuel injectors which are able to open and close a lot of times in a second. The fuel from the fuel tanks is fetched and is transported to the fuel injectors by the fuel lines. After reaching the fuel injector, the fuel is raised to the precise level of pressure to which it is needed to raise with the help of a pressure regulator. Then the fuel gets divided into a number of chambers. Then, the fuel is sprayed into the combustion chamber.

There are basically two kinds of fuel injectors- Mechanical fuel injectors and Electronic fuel injectors.

Mechanical Fuel Injectors:

The method used by mechanical fuel injectors to inject fuel is quite similar to the carburetor systems which were used in the past years but in actual, there is an important difference between these two systems. The carbureted system is used to fetches low-pressure fuel from the fuel tank while the mechanical fuel injector system is used to pump a high-pressure fuel from the tank containing fuel. The basic principle of mechanical fuel injector’s working is pumping a high-pressure fuel from the fuel tank.

The fuel enters the accumulator after getting pumped. An accumulator can be thought of as something that stored fuel temporarily. Then the metering control unit of the system comes into the picture. It distributes the fuel to various cylinders. The delivery of the correct quantity of fuel into various cylinders in the correct quantity of time is very important.

Also Read:  Best Shocks For Chevy Tahoe | Reviews

The fuel and air must be mixed with a lot of accuracies when it enters the cylinder. The flap valve lets the fuel come in the right flow to be mixed with the air in the correct quantity. In case the speed of the vehicle is increased or decreased, the flap valve keeps the mixture in proportion.

Two springs are known as the mainspring and the Plunger spring is used here. The mainspring controls the fuel going to the fuel injector, the fuel which is coming from the fuel pump is pressurized, and this pressure helps the mainspring to get opened and the fuel goes inside the fuel injector.

The fuel then mixes with the air, the pressure gets increased, this increasing pressure causes the plunger spring to move and hence makes the plunger move towards out which makes the nozzle to open. Then the controlled spray of the fuel takes place.

Once the fuel injection is complete for a given cycle, the pressure goes down and gradually the plunger comes to its initial position. The spray or the fuel pumping stops.

Electronic Fuel Injectors:

The amount of fuel and the tension used to open and close the valve using the spring is different in these systems than the mechanical ones as the electronic systems use an electronic control unit controlling its functions.

A number of sensors are used to keep track of things such as the temperature of the air, air intake pressure, the temperature of the engine, speed of the engine and position of the accelerator.

Also Read:  How Do I Get My Transmission Out Of Safe Mode?

According to the calculations done by the ECU to which everything inside the engine is connected, the engine calculates the amount of fuel that needs to enter the cylinders. This input is given to the ECU. The processing very fast.

Fuel rails, connected to the fuel injector transfer the fuel from the fuel tank. The ECU calculates the quantity of fuel that needs to be squirted and the valves which are to be opened. When the electronic signals are sent from the ECU to the fuel injector pins, electromagnet inside the fuel injector which makes the plunger move towards out is created. A way for the fuel to pass is created. The nozzle gets opened, and the fuel is sprayed.

Then the ECU stops the electronic signal which was being sent to the fuel injector which deactivates the electromagnet. Afterward, nothing pushes the plunger outward. So, the nozzle gets closed and the fuel spray gets stopped.


A fuel injector is very important in engineering and it has helped to deliver the exact quantity of fuel needed for combustion.

If you have any doubts related to the working of fuel injectors or fuel injectors in general, please drop a comment below.

Leave a Reply