Give the functions of boost venturi, Emulsion tube, Acceleration pump & altitude compensation mechanism present in actual carburetors.

 Here are the functions of key components found in actual carburetors used in SI engines:

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🔸 1. Boost Venturi (Auxiliary Venturi)

✅ Function:

• Located inside the main venturi, it helps increase the air velocity at the throat.

• Creates a stronger vacuum signal near the fuel discharge nozzle (main jet).

• Enhances fuel atomization and mixture formation, especially at low airflow rates.

🔧 Benefit:

• Improves fuel delivery accuracy during part-throttle operation or transients.

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🔸 2. Emulsion Tube

✅ Function:

• Located between the main jet and the discharge nozzle.

• Allows air and fuel to mix before entering the venturi.

• Contains air bleed holes that introduce air to form an emulsion of fuel and air.

🔧 Benefit:

• Ensures smoother fuel delivery and better atomization.

• Helps prevent rich mixtures at low speeds and lean surging.

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🔸 3. Acceleration Pump

✅ Function:

• Provides an extra squirt of fuel when the throttle is suddenly opened.

• Compensates for the temporary lean condition caused by sudden increase in air flow (due to fuel inertia).

🔧 Benefit:

• Improves acceleration performance.

• Prevents hesitation or stalling when the throttle is snapped open.

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🔸 4. Altitude Compensation Mechanism

✅ Function:

• Adjusts the fuel-air mixture based on changes in atmospheric pressure (altitude).

• As altitude increases, air density drops → system reduces fuel flow to maintain the correct air-fuel ratio.

🔧 Types:

• Barometric compensators, vacuum diaphragms, or electronic sensors.

🔧 Benefit:

• Maintains fuel efficiency, power, and emission control at high altitudes.

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✅ Summary Table

Component	Function
Boost Venturi	Increases vacuum for better fuel draw and atomization
Emulsion Tube	Mixes air with fuel to create an emulsion for smoother delivery
Acceleration Pump	Provides extra fuel during sudden throttle opening
Altitude Compensation	Adjusts fuel flow to maintain correct mixture at varying atmospheric pressure

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These components work together to ensure that the carburetor delivers a consistent and optimal air-fuel mixture under all driving conditions.