What is the function of the fuel supply system?

It is responsible for the supply of gasoline /  diesel fuel  to the engine for operation. It is responsible for dosing the mixture and ensuring the greatest cleanliness of the fuel entering the cylinder.

There are some differences between diesel and gasoline engines , then we list the parts that make up the power system of a vehicle and its operation. We are going to address the fuel system for gasoline and  diesel .

Parts of the fuel supply system

Tank or fuel tank

It is the fuel tank or housing , it has a drain plug, a vent hole and a fill cap. A fuel level indicator mechanism inside the tank and the pipeline. There are metallic tanks, but currently they are plastic, they reduce the level of sediment, corrosion and weight. Applies for gasoline and  diesel .

Filter or sedimentation vessel

The fuel filter , in this the waste, impurities and water of the fuel are deposited allowing its decantation, to avoid obstructions in the carburetor or injectors.

Feed pump

It is a suction pump that can be electric or submersible, controlled from the engine's camshaft, in charge of taking the fuel out of the tank to send it to the injector rail.


It is the mechanism responsible for mixing gasoline with air. Carburetor system is the oldest system of supply of fuel .


It is responsible for mixing gasoline with air and dosing and atomizing the mixture to all cylinders.

Fuel lines

The pipes are responsible for carrying and returning the fuel between the tank and the carburetor or injection rail.

Parts of the diesel feeding system

The structure of the diesel vehicle  feeding system  is similar to that of gasoline , it differs in that the injection pump, pipes and injectors are high pressure. Some additional elements such as the overflow valve, different air filters and fuel filters .

Injection pump

It is responsible for sending the fuel in a synchronized and dosed way to each of the injectors located on each of the cylinders.

Injector holder

This element is attached to the injector, is located in the cylinder head or in the block, its function is to provide adequate pressure to the injector needle and generate the output fan, also to give the output to the  remaining diesel  .


The function of the injector is to atomize the fuel , distributing evenly next to the compressed air, or directly on the cylinder. The injector has holes through which the fuel comes out and a needle. The pressure overcomes the spring that has the needle, making it move allowing the exit.

Fuel lines

They are high pressure lines, they communicate the pump with the injectors, driving the fuel with pressures of up to 5000 psi, the middle line that leads from the pump to the filters and to the injection pump, they are lines without pressure, they communicate the tank with the pump and return of the injectors to the tank.