How Do Diesel Fuel Injectors Work?

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How Do Diesel Fuel Injectors Work?


A fuel injection system mixes air with gasoline inside an internal combustion engine. Fuel injection systems vary by fuel type, although the adoption of electronic fuel injection has caused many systems to converge. Fuel injection systems, which forcibly spray fuel into the combustion chamber at high pressure, have largely replaced carburettors, which use a low pressure fuel delivery system. One important difference between diesel and unleaded gasoline fuel injection systems is the location in which the injection takes place. In regular gasoline engines, fuel is sprayed into a separate vessel outside of the cylinder chamber. The fuel is sucked into the cylinder chamber during the cylinder's intake stroke, where it mixes with air and combusts. By contrast, a diesel fuel injection system sprays the fuel directly into the cylinder chamber.

Mechanics of Diesel Fuel Injectors

Basic diesel fuel injectors contain a fuel supply line, an intake valve, an exhaust valve and the fuel injection apparatus. Each cylinder is attached to its own fuel supply line, all of which run from the fuel tank to the engine. Fuel is transferred through these fuel supply lines to the fuel injector device attached to each cylinder. Along the way, the fuel passes through a filter that removes residue and impurities. When the diesel fuel reaches the injector device, it becomes highly pressurised. The fuel injector is attached to a small pump, which forces air into the injector and pressurises the diesel fuel. The injector then sprays the diesel fuel through a small nozzle into the cylinder's combustion chamber. The nozzle contains a series of small holes, which ensure even distribution of the diesel fuel into the cylinder's combustion chamber. An air intake valve sucks air into the chamber, which mixes with the vaporised diesel fuel and intensifies the combustion. An exhaust valve removes the resulting emissions from the combustion chamber, and a return fuel line removes any excess fuel from the combustion chamber and returns it to the fuel tank.

How Do Diesel Fuel Injectors Work?

Advancements in Diesel Fuel Injectors

Diesel fuel injectors have become increasingly sophisticated and efficient in recent years. Modern diesel fuel injectors are regulated by computers, which monitor the amount of air entering the engine and regulate the amount of diesel fuel that is sprayed into the combustion chamber. Fuel injectors have also been modified slightly to accommodate the use of biodiesel fuel, which is diesel fuel made from plant and animal oils rather than from petroleum. Biodiesels are not as powerful as petroleum-based diesel fuel, so more biodiesel fuel is required to run an engine. Hence, diesel fuel injector pumps have become more powerful and more closely integrated with the system's computer in order to ensure that the appropriate amount of fuel is delivered to the combustion cylinder.

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