The carburetor is the device that makes the air-fuel mixture in gasoline engines. To get the engine to run more economically and get the most power output, it is important that gasoline is in the best condition. To achieve an optimum air-fuel mixture, the carburetor will use various techniques.
The carburetor basically operates with the same principle of an airbrush. When the air is blown, crossing the axis of the spray pipe, the internal pressure of this pipe falls. The liquid inside the sprayer is consequently pushed into the pipeline and atomized thanks to the friction with the air.
Construction and operation of the carburetor
The carburetor has a division where gasoline and air are mixed, and another where gasoline is stored (float chamber). These parts are divided but connected through the main nozzle.
The air-fuel ratio is decisive in the operation of the engine. The key is that the air must be cold for this performance to be effective.
During the engine intake cycle, the piston lowers inside the cylinder and the internal pressure of the cylinder decreases, drawing air from the purifying filter, carburetor and intake manifold, flowing to the cylinder. When this air passes through the narrow portion of the carburetor, the speed increases (Venturi effect), drawing gasoline from the main nozzle. This aspirated gasoline is both blown and dispersed by the same air flow and mixed with it. This air-fuel mixture is sucked into the cylinder.
The amount of air entering the carburetor is controlled by the acceleration valve, which is connected to the accelerator pedal. This same factor thus determines the amount of gasoline aspirated.
Type of carburetors
Classification of the different types of carburetors
- Fixed diffuser carburetor. It is a type of carburetor very used. When the throttle butterfly opens from the slowed down position, its gauges open progressively.
- Variable diffuser carburetor. The section of the diffuser is controlled by a vacuum valve, the function is to increase or decrease the diameter of the diffuser according to the operation of the motor.
- Double body carburetor. This type of carburetor has a fixed diffuser. It is formed by two bodies or diffusers inside your body. The two throttle butterflies can be opened simultaneously or one after the other, depending on the type of carburetor that is.
- Carburetor inverted. It is a fixed diffuser carburetor in which the air penetrates from above, vertically.