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Professional mechanic testing diesel injector in his workshop.

How Do Fuel Injectors Work? Electrical | Mechanical | Explained

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 to survive today. But just buying does not help, the vehicle owner has got several 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.

To take proper care of her/his vehicle, the owner has to understand how the vehicle 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 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 a 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 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.

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

How Do Fuel Injectors Work?

The ECU (Electronic Control Unit ) or springs control the fuel injectors which can open and close a lot of times in a second. The fuel from the fuel tanks is fetched and 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 several chambers. Then, the fuel is sprayed into the combustion chamber.

There are 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 actuality, 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 a 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.

The fuel and air must be mixed with a lot of accuracy 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 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 are different in these systems than the mechanical ones as the electronic systems use an electronic control unit to control their functions.

Several 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.

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 is 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, an electromagnet inside the fuel injector which makes the plunger move 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.

1. What Causes Injectors To Fail?

Fuel injectors will fail when debris (water, dirt particles, etc.) or rust find their way into the system and, after time, plug up the nozzle, the armature, or the nozzle needle gets stuck. To prevent debris from getting into the system, we recommend doing everything you can to help keep your fuel system clean.

2. What Are The Signs Of Fuel Injector Problems?

Fuel injector symptoms for bad, faulty, dirty, clogged, or leaking injectors are :
  • Starting issues.
  • Poor idle.
  • Failed emissions
  • Poor Performance.
  • The engine does not reach full RPM.
  • Increased fuel consumption.
  • Rough engine performance.
  • Surging and bucking under various throttle loads.

3. What Triggers Fuel Injection?

The amount of fuel injected is controlled by a flap valve located in the engine’s air intake. The flap sits beneath the control unit and rises and falls in response to airflow – as you open the throttle, the ‘suck’ from the cylinders increases the airflow, and the flap rises.

4. Do Injectors Need Spark Plugs?

Modern engines with smart gasoline direct injection need spark plugs perfectly geared to the specific requirements of each combustion chamber. This is the only way to facilitate future optimizations in terms of performance, fuel economy, and emission reduction.

Conclusion:

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.
Cheers!