What is the purpose of fuel injectors or a carburetor in engines?

• A. Deliver the correct air-fuel mixture to the combustion chamber.
• B. Regulate the engine's idle speed.
• C. Act as the ignition source for the spark plug.
• D. Cool the engine components.

Answer: (A)

Delivering the correct air-fuel mixture to the combustion chamber is the essential role of fuel delivery devices. A carburetor creates the mixture by drawing in air and using a venturi to meter fuel into that air stream, aiming for a proper ratio so the fuel burns efficiently in the cylinder. Modern engines use fuel injectors that precisely meter and atomize fuel into the intake air stream or directly into the cylinder, with the engine control system adjusting quantity based on speed, load, temperature, and other sensors. This accurate mixture is what enables reliable ignition, smooth operation, good fuel efficiency, and proper power output. Other options describe roles handled by different systems—idle speed is controlled by throttle or idle control mechanisms, the ignition source is the spark plug, and cooling is managed by the engine’s cooling system.