Why is a fuel-injected reciprocating engine less prone to icing than a float carburetor engine?

Why is a fuel-injected reciprocating engine less prone to icing than a float carburetor engine?

• A. It uses a heated carburetor.
• B. In a fuel-injected engine, the liquid fuel evaporates in the intake valve chamber of the hot cylinder head.
• C. It has no carburetor venturi to cause cooling.
• D. It uses a separate icing sensor.

Answer: (B)

Icing in the intake system is driven by cooling that happens when air flows through a carburetor’s venturi, causing the fuel to evaporate and the surrounding surfaces to freeze. In a fuel-injected engine, there is no venturi to create that cooling effect, and the fuel is not sprayed into a cold carburetor passage. Instead, the liquid fuel is injected and vaporizes in the warmer area of the intake, specifically in the intake valve chamber warmed by the cylinder head. The heat from the hot cylinder head helps vaporize the fuel and keeps the intake region above freezing, so ice formation is much less likely. That’s why the reason described—evaporation of the liquid fuel in the intake valve chamber of the hot cylinder head—is the best explanation.

Icing in the intake system is driven by cooling that happens when air flows through a carburetor’s venturi, causing the fuel to evaporate and the surrounding surfaces to freeze. In a fuel-injected engine, there is no venturi to create that cooling effect, and the fuel is not sprayed into a cold carburetor passage. Instead, the liquid fuel is injected and vaporizes in the warmer area of the intake, specifically in the intake valve chamber warmed by the cylinder head. The heat from the hot cylinder head helps vaporize the fuel and keeps the intake region above freezing, so ice formation is much less likely. That’s why the reason described—evaporation of the liquid fuel in the intake valve chamber of the hot cylinder head—is the best explanation.