Cara Kerja 7 Sistem Pada Karburator

Summary

This transcript provides an educational explanation of the conventional fuel system, particularly focusing on the carburetor's working mechanism. It covers various subsystems, including the float system, idle system, low and high-speed systems, power system, acceleration system, and choke system. Each system is explained in detail, emphasizing how air and fuel are mixed to meet engine requirements. The operation of key components such as the needle valve, throttle valve, power piston, and choke is outlined, helping students understand how fuel flow and air intake work to optimize engine performance.

Takeaways

• 🛠️ The lesson continues from previous sessions on conventional fuel systems, specifically focusing on how carburetors function.
• 💨 Carburetors mix air and fuel to ensure the right blend based on engine conditions, allowing the engine to run efficiently.
• 🏎️ The carburetor operates by creating a vacuum in the cylinder, which pulls in fuel and air to form the necessary mixture for combustion.
• ⚖️ The float system in the carburetor maintains a constant fuel level in the float chamber, allowing the system to function smoothly.
• 🚦 Idle or stationary systems in the carburetor work when the throttle is fully closed, ensuring that the engine can continue running at low speeds.
• 🔧 The idle mixture adjustment screw helps control the amount of fuel that enters the engine at idle speed, commonly referred to as the 'air screw.'
• 🏁 The high-speed system engages when the throttle opens more, allowing greater airflow and creating more vacuum, which pulls additional fuel into the mix for higher engine speeds.
• 🔋 The power system activates during heavy engine loads, where additional fuel is delivered to increase engine power output.
• 🚀 The acceleration system adds more fuel when the gas pedal is pressed suddenly, helping to prevent engine hesitation during rapid acceleration.
• ❄️ The choke system enriches the fuel mixture when the engine is cold, making it easier to start by reducing the airflow and increasing the fuel entering the engine.

Q & A

What is the primary function of a carburetor?

The primary function of a carburetor is to mix air and fuel in the correct proportions for combustion based on the engine's conditions.

How does the float system in a carburetor work?

The float system maintains a constant fuel level in the float chamber. When the fuel level drops, the float lowers, opening the needle valve to allow more fuel in. When the fuel level rises, the float closes the valve to stop the flow.

What happens during the idle system operation of a carburetor?

During idle, the throttle valve is fully closed. The engine draws a fuel-air mixture from the idle circuit, where fuel is drawn from the float chamber through the main and slow jets, mixing with air before entering the intake manifold.

What is the role of the slow jet in the carburetor?

The slow jet controls the amount of fuel mixed with air during low engine speeds or idle, ensuring smooth engine operation.

How does the high-speed system of a carburetor function?

The high-speed system operates when the throttle is opened, increasing air velocity through the venturi. This creates a vacuum that draws more fuel from the float chamber, mixing with air through the main jet and main air bleed for high-speed operation.

What is the function of the power system in a carburetor?

The power system provides extra fuel when the engine is under heavy load. A power piston opens the power valve, allowing additional fuel to mix with air, increasing the engine's power output.

How does the acceleration system of the carburetor work?

The acceleration system provides extra fuel when the gas pedal is pressed suddenly. A plunger pushes fuel through the pump jet, ensuring quick throttle response and preventing engine hesitation.

What is the purpose of the choke system in a carburetor?

The choke system enriches the fuel mixture during cold starts by restricting airflow, increasing the amount of fuel in the mixture to help the engine start more easily.

What happens when the power valve opens in the power system?

When the power valve opens, additional fuel is supplied from the power valve along with the main jet, increasing the fuel flow to meet the engine's higher power demand.

Why is it difficult for a cold engine to start without the choke system?

In cold conditions, fuel does not vaporize well and can stick to the intake manifold walls, resulting in a lean fuel mixture. The choke system compensates by increasing the fuel mixture to make starting easier.