What is the primary function of a fuel injector in an engine?

The primary function of a fuel injector in an engine is to deliver fuel into the combustion chamber. This process is crucial for proper engine operation, as the fuel injector is responsible for administering the correct amount of fuel at the right time for combustion to occur efficiently. The injector atomizes the fuel, creating a fine mist that mixes with air in the combustion chamber, promoting complete combustion, which leads to better performance, fuel efficiency, and reduced emissions.

Other options do not capture the function of a fuel injector accurately. For example, cooling the engine involves different components such as the radiator and coolant system rather than the injector. Draining excess fuel is not a function associated with fuel injectors; this task would typically be managed by a fuel return system. Igniting the air-fuel mixture is the role of the spark plugs, not the fuel injector. This clear differentiation of functions highlights why delivering fuel into the combustion chamber is the essential duty of the fuel injector.