What Is the Function of a Fuel Injector?

by Edmund Gary
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The function of a fuel injector is to spray atomized fuel into the combustion chamber of an internal combustion engine. Fuel injection became the primary fuel delivery system in automobiles starting in the mid-1980s. The spray from a fuel injector can be continuous or intermittent.

Definition of a Fuel Injector

The fuel injector is a small nozzle into which liquid fuel is injected at high pressure. It works like a spray nozzle of a pressure washer. The placement of the injector can be in a different part of the engine depending upon the type of fuel injection system is being used. High pressure from the fuel pump feeds the fuel to the fuel injector.

Precise Fuel Metering

The fuel injector meters the fuel more precisely than a carburetor. Therefore, no fuel is wasted. The result of such precise metering is increased power, lower emissions and lower fuel consumption. The right amount of fuel is squirted into the combustion chamber or throttle body. Excess fuel goes back to the fuel tank. A metering unit delivers fuel to the fuel injectors, according to the Reader's Digest Complete Car Care Manual.

General Motors said in 1982 that the fuel injection system delivers the proper amount of fuel after the electronic control module reads manifold vacuum, engine temperature and engine rotations per minute.

Maximum Airflow

The fuel injector also frees the intake system for maximum airflow. The accelerator pedal is not necessarily a gas pedal. It controls the position of the throttle plate. The airflow is increased or decreased depending upon the accelerator's position.

The airflow and fuel mixture is optimized by the engine control unit hundreds of times per second. The airflow and fuel mixture determine the length of time the fuel injector sprays fuel into the port, according to Auto Media.

Fuel injection Modes

The fuel injector of a continuous fuel injection system sprays fuel into the intake port on a continuous basis. This type of injector has been suitable for the use in passenger cars.

The intermittent fuel injection system has the fuel injector spray fuel into the intake port at specific intervals. This mode has been the basis for diesel engines ever since they were first manufactured, according to the Reader's Digest Car Complete Car Care Manual.

Fuel Injection Systems

The throttle body injection has the fuel injector placed over injector valves. The fuel is sprayed into the throttle body. This is one of the earlier types of fuel injection systems employed when car manufacturers were replacing the carburetor with fuel injection.

A multiple-port fuel injection system has an injector for each cylinder. The injector sprays the fuel directly at the intake valve. The fuel injector is able to deliver more-consistent metering of fuel to each cylinder, and the results are more power and lower emissions, according to AffordableFuelInjection.com.

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