Prior to 1980s, all internal combustion engines, irrespective of their applications, did not have fuel injectors. Instead, a device known as a carburetor was installed, to evenly and proportionately mix air and fuel (diesel or gasoline). This device was the basis of the earlier combustion engines, and it also had some drawbacks. It was not exactly reliable, as it would malfunction, especially in the case of sudden atmospheric changes and temperature fluctuations.
One of the most unreliable aspects of the carburetor is that it stops working if the engine temperature is too high. It also requires a manual adjustment, which cannot be made by all people. Hence, as an alternative to overcome the demerits of carburetors, fuel injectors were developed by automobile companies. Nowadays, very few automobiles are attached with carburetors.
The carburetor has a very simple functioning procedure. It simply mixes the fuel and air, and inserts this mixture in the piston block. However, the fuel injectors have a more complex functioning; they rely on a high pressure piping network in the engine.
After the fuel leaves the fuel tank, a filter is used to purify it from all unwanted contents and residues, which run through this tank. An individual injector is actually an electromagnetic device that is shaped roughly like a syringe. There is a magnet attached at its top, and a small valve is present at its bottom. Due to the pressure of the fuel that comes through the filter, the valve is forcefully closed. The piston lies beyond this valve.
The magnet is in a suspended state, which is done with the help of a spring. An electric coil surrounds the magnet, and a distance of about half an inch is maintained between them. When the injector goes into action, an electrical timing system which is fitted on to the engine, alerts the coil with a mechanical charge. The magnet due to this charge gets attracted towards the coil, and moves in an upward direction.
Due to this process, the valve at the bottom of the injector is lifted upwards, and fuel is sprayed with an immense pressure into the piston block. The pressure, heat, and the electrical spark from the spark plug, cause the whole fuel to ignite and explode, propelling the automobile forward. As a result of this propulsion, the electric charge is canceled, and the injector comes back to its normal state, ready for a new firing.
The development of fuel injectors has revolutionized the firing process in internal combustion engines. The biggest advantage is that the fuel flow in engines is properly regulated. This prevents fuel wastage, and also results in concentrated fuel utilization. The second advantage is that emission of harmful compounds like carbon monoxide, is reduced drastically. Some highly reputed automobiles manufacturers have also managed to decrease such emissions. The injectors are highly reliable, and work efficiently in any natural conditions.