Working of Diesel Fuel Injection System

Earlier, diesel engines were used only in heavy vehicles like trucks, ships, etc. They used to emit black soot and a lot of noise. With the introduction of electronic fuel injection systems in 1980s, diesel engines became popular even in small vehicles like passenger cars. Now, diesel engines with electronic fuel injection system are known for high fuel efficiency and less emissions.

Fuel injection system (FIS) is a vital part of an internal combustion engine. Both gasoline and diesel engines have fuel injection systems and their main objective is to convert chemical energy to mechanical energy through small explosions and combustion. However, there is a difference in the way the air and fuel mixture is burnt and combustion happens in these engines. This article discusses how the diesel fuel injection system works.

Air is already compressed in the chamber and then the fuel is sprayed
In a diesel engine, the air is already present in the combustion chamber and is compressed and heated up. The fuel is then injected into the chamber with a very high pressure through fuel injectors. The compressed air then causes ignition as soon as it is exploded with high pressure fuel.

Fuel is sprayed through fuel injector
The fuel, which is the causative factor of energy for the vehicle, is sprayed by the fuel injector. Diesel engines unlike gasoline engines do not have spark plug to ignite the mixture. The fuel sprayed with high pressure by fuel injectors itself will acts as a spark plug. Fuel injectors of diesel fuel injection system are capable of spraying fuel with massive pressure of 10,000 psi - 30,000 psi when compared to that in gasoline engines (10 psi – 60 psi).

Fuel injector is most effective part in diesel fuel injection system
Diesel fuel injection system consists of three major components. They are fuel injectors, injection pump and engine control unit. The fuel injector is an important part of the diesel fuel injection system. It sprays fuel at a high pressure into the combustion chamber in the form of fine mist. The smaller the droplets are, the more probability of the fuel becoming vapor for complete combustion.

Fuel injectors in diesel fuel injection system are stronger than those in gasoline engines because they can withstand high pressure of about 10,000 psi - 30,000 psi and high temperatures of about 400O C.

The induction valves in fuel injection system help get the air/fuel circulated throughout the engine and make sure that the maximum amount of diesel is burnt to improve fuel efficiency and performance of the car.

Thus, highly capable fuel injectors make diesel fuel injection system sturdier than gasoline fuel injection system.

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