What is the primary function of a fuel injector?

The primary function of a fuel injector is to deliver a precise amount of fuel into the engine's intake manifold or combustion chamber. This function is critical for optimal engine performance, as the injector must accurately meter the fuel to ensure the correct air-fuel mixture for combustion. An appropriate mixture allows the engine to operate efficiently, providing the necessary power while minimizing emissions.

Fuel injectors use electronic controls to determine the correct timing and quantity of fuel to inject based on various factors, including engine speed, load, and temperature. This precision is vital, as too much fuel can lead to incomplete combustion and increased emissions, while too little fuel can cause the engine to run lean, which may lead to overheating or performance issues.

Other options address different aspects of fuel delivery and combustion but do not capture the primary function of the injector itself. For instance, while ensuring complete combustion is important (as mentioned in one of the other choices), it is the injector's role in supplying the right amount of fuel that directly impacts the combustion process. Delivering fuel at high pressure to the fuel tank and regulating fuel temperature before it enters the engine are not functions performed by the injector, but rather roles of fuel pumps and cooling systems, respectively.