The fuel system is an indispensable part of the engine system. While all other compositions of the engine system (Valve system, Cooling system, lubricating system, Ignition and electrical system) remain essential for the perfect functioning of and engine and ultimately, a vehicle, motorcycle or any object in which the Engine (Usually the Internal Combustion Engine)
supplies power to do useful work, 
I find the Fuel system the most basic and interesting of them all.

This piece will bring in to focus the fuel system in all of it's glory, its functions as it relates to the Internal Combustion engine (A heat engine in which the intermittent or continuous burning of a fuel takes place inside a combustion chamber, the resulting pressurized gas acting directly on the engine to do useful work such as piston engine, gas turbines, jet engines, rocket).

This will be done by adopting a microscopic view of all of the parts of the fuel system before rounding up with a holistic take.

There are two systems involved in the process of fuel delivery to the engine. (Depending on how the energy in the fuel is to be released).

The petrol system consists of the carburetor, a major agent of this fuel system type. In the petrol system, the petrol and air are first mixed in definite proportions (usually 1:15). This is usually done by the carburetor, the mixture is then brought into the cylinder by the partial vacuum created by the intake stroke of the piston. (First stroke).

The mixture is then burnt by an electric spark generated at the end of the compression stroke. (This spark is usually generated by the battery system or magneto system which play the major roles in the ignition aspect of the engine system).

On the other hand, in the diesel system, only the air is drawn in during the intake stroke of the piston. The air is highly compressed  (more compression than that of the petrol system). At the end of the the compression Stroke, diesel fuel is then sprayed under pressure into the cylinder and burnt by the heat of the compressed air.

Now, I will discuss the basic components of the fuel system. Whenever you hear the two words "fuel system" these guys should come to mind.

Fuel tank or storage.
A container of fuel. Whether or nor diesel or petrol is used as fuel, it us necessary to have a tank to store and supply fuel to the internal combustion engine (ICE).
![220px-Wasserstoffeinfüllstutzen_eines_BMW.jpg](https://steemitimages.com/DQmR2Es38brLm5cjJ95ErmL8HbvRgViVTkLugi4j9Zo5wym/220px-Wasserstoffeinf%C3%BCllstutzen_eines_BMW.jpg)

Air supply system (Consists of the air cleaner).
This device works ultimately to supply clean air necessary for the process of combustion that will take place during the power stroke.

Oxygen is contained in air.(About) and fuel cannot burn without oxygen.

Air: fuel ratio regulator.
Depending on whether petrol or diesel is used as fuel.

For petrol engines, the carburettor is used.
For diesel engines, air fuel mixing occurs inside the cylinder (Unlike the petrol engine where the charge I.e the air fuel mixture goes in at the intake stroke).
Diesel fuel is injected into the cylinder only at the end of the compression stroke. The device used to inject the fuel is referred to as the fuel injector.

Fuel filter 
A filter functions in separating suspended, dissolved, particulate matter from a fluid, solution or any other substance.
The fuel filter prevents the possibility of fuel clogging in either the carburettor or fuel injector.
Fuel filters are found in locations such as, Screen at the fuel tank filter, sediment bowl, fuel filter at the entrance of a fuel injector pump.

Fuel pump.
Depending on the position of the fuel tank. The pump helps in directing the fuel to where it is most needed.
The fuel tank may be located above or below the carburettor. If below, a pump is required to raise the fuel. However, If the fuel is located above the carburetor, gravity does the job and the fuel flows without the pump serving as aid.
![220px-High_pressure_fuel_pump.JPG](https://steemitimages.com/DQmfNizFJ95vrKuK2Tnw3bCy4uUXS5uRmxxcUExHvUCQJZk/220px-High_pressure_fuel_pump.JPG)

Fuel injector.
Used in diesel engines to inject fuel at very high pressure into the cylinder, where it mixes with the hot compressed air.
![300px-Jeep_2.5_liter_4-cylinder_engine_chromed_i.jpg](https://steemitimages.com/DQmUrzQFsbTyZC3nuE8jDW5cyKcgnx9yS96zFGb87Mb2pUP/300px-Jeep_2.5_liter_4-cylinder_engine_chromed_i.jpg)
Fuel rail connected to the injectors that are mounted just above the intake manifold on a four-cylinder engine

Other components of the Fuel system include the manifold (a collection of tubular components used conduct air or the fuel-air mixture to the engine), air cleaners (dry air cleaner, oil bath air cleaner).

So what exactly does the fuel system achieve with all of these listed components you ask?

The basic function of the fuel induction system is to effectively and efficiently mix the correct quantity of fuel and air and then deliver into to the cylinder in a condition to be readily ignited.

Hence just like a colony of ants or termites each part of the fuel system plays its part for the overall functioning of an engine whether or not its a petrol or diesel system.

To take an holistic view of the fuel system, (Petrol system) The piston in the engine moves on it's first stroke, i.e the intake stroke. This creates a vacuum in the cylinder and air rushes in through the carburetor to fill this. 

As this is being done, the air picks up fuel from the venturi tube of the carburetor (constricting tube that reduces fluid pressure) hence the fuel is now in form of spray and as it travels towards the cylinder, it gets properly mixed with the air. 

This thorough mix is referred to as the charge (particular only to the petrol system) and is subsequently burnt in the cylinder after the compression stroke.

Image source -Wikipedia.

The Fuel system is a wonderland of semi-intricacies, I particularly enjoyed writing this. I sure hope you did too!

Feedback is very much welcome!