Smaller spark ignition engines vaporize gasoline by which process?

• A. Vapourizers
• B. Atomization
• C. Electric heaters
• D. Carburetion

Answer: (D)

Gasoline in small spark-ignition engines is prepared for combustion through carburetion—the process of forming a combustible air–fuel mixture in the carburetor. As air flows through the carburetor, it passes the venturi, where the speed increases and pressure drops, drawing fuel from the float chamber. The fuel is atomized into a fine mist and then vaporizes as it mixes with the incoming air, creating a uniform mixture that can be ignited by the spark. This combined action of atomizing, vaporizing, and metering the fuel is what carburetion describes, making it the correct answer. Atomization alone only describes droplet formation and doesn’t guarantee complete vaporization and proper mixture; vapourizers isn’t a standard term here, and electric heaters aren’t used to vaporize gasoline in typical small engines.