Carburetor - Working of Carburetor - How Carburetor Works Theoretically

Summary

This video explains the function and components of a carburetor, which mixes air and fuel for engine combustion. Key elements include the float chamber that maintains fuel levels, the venturi that creates a pressure drop to draw fuel, and the throttle valve that regulates the mixture for varying engine power. The choke valve is crucial for cold starts, allowing a fuel-rich mixture to facilitate ignition. Understanding these components is essential for grasping how carburetors operate effectively in internal combustion engines.

Takeaways

• 😀 The carburetor's main function is to create a combustible air-fuel mixture tailored to engine load requirements.
• 😀 Key components of a carburetor include the float chamber, fluid discharge nozzle, metering orifice, venturi, throttle valve, and choke valve.
• 😀 The float chamber maintains a constant gasoline level; if it falls, the float opens the fuel supply valve to refill it.
• 😀 Air drawn into the venturi increases in velocity and decreases in pressure, causing fuel to atomize and mix with air.
• 😀 The throttle valve regulates the air-fuel mixture delivered to the engine, impacting power output based on its position.
• 😀 When the throttle valve is closed, it allows enough air-fuel mixture for idling; when open, it increases power by delivering more mixture.
• 😀 The choke valve reduces airflow during cold starts, providing a fuel-rich mixture that helps start the engine in lower temperatures.
• 😀 The pressure difference between the float chamber and venturi throat is referred to as carburetor depression.
• 😀 Properly maintaining the float level prevents fuel overflow through the discharge nozzle.
• 😀 Understanding the carburetor's operation is essential for optimizing engine performance and efficiency.

Q & A

What is the main function of a carburetor?

The main function of a carburetor is to produce a combustible air-fuel mixture by mixing the correct amount of fuel with air, according to the engine's load requirements, before supplying it to the engine cylinder.

What are the key components of a simple carburetor?

A simple carburetor mainly consists of a float chamber, fluid discharge nozzle, metering orifice, venturi, throttle valve, and choke valve.

How does the float in the carburetor function?

The float maintains a constant level of gasoline in the float chamber. If the fuel level falls below the designed level, the float opens the fuel supply valve to admit more fuel, and it closes the valve when the proper level is reached.

What is the role of the venturi in a carburetor?

The venturi is a section with a minimum cross-sectional area that increases air velocity and decreases pressure at the throat, creating a vacuum that draws fuel from the float chamber through the discharge nozzle.

What is carburetor depression?

Carburetor depression is the pressure difference between the float chamber and the throat of the venturi, which allows fuel to be drawn into the air stream.

How does the throttle valve affect engine power output?

The throttle valve controls the amount of air-fuel mixture entering the engine. Fully closing it results in idling with minimal airflow, while opening it allows more air and fuel to flow, increasing engine power output.

What is the purpose of the choke valve?

The choke valve restricts air supply, enriching the fuel mixture, which is particularly useful during cold starts when fuel vaporization is difficult.

What happens when the throttle valve is partially open?

When the throttle valve is partially open, less air flows through the venturi, resulting in a lower pressure drop and consequently less fuel discharged through the nozzle, reducing the power output of the engine.

Why is the fuel level in the float chamber kept slightly below the discharge nozzle?

The fuel level is maintained slightly below the discharge nozzle to avoid overflow through the jet while ensuring a steady flow of fuel when needed.

How does the carburetor assist in starting an engine during cold weather?

In cold weather, the choke valve is closed to provide a fuel-rich mixture, which helps in starting the engine since more fuel and less air facilitate better combustion.