PPL » Aircraft Tech Knowledge (A) » Carburation
12.12.2 Explain the principle of carburation.
The principle of carburation is to mix air and fuel in the correct proportions to create a combustible mixture that can be used by an internal combustion engine.
In a carburetor, air is drawn into the engine through an air intake and passes through a narrow passage called a venturi.
As the air flows through the venturi, its velocity increases and its pressure decreases.
This causes fuel to be drawn from a fuel bowl into the airflow and mixed with the air in the venturi.
The fuel-air mixture is then delivered to the engine through an intake manifold.
The carburetor uses various components to control the amount of air and fuel that enters the engine.
The throttle controls the amount of air that enters the carburetor, while the fuel bowl and float control the amount of fuel that is delivered to the venturi.
The choke, which is a valve that restricts the flow of air into the carburetor, is used to create a richer fuel-air mixture when the engine is cold and needs more fuel to start.
The goal of carburation is to create a fuel-air mixture that is as close to the stoichiometric ratio as possible.