What Is a Vacuum Clutch? – Parts, Working, Applications, Diagram

Find out what a vacuum clutch is and how it works. Explore its working, benefits, and applications in this in-depth guide. Perfect for those looking for more information.

What Is Vacuum Clutch?

A vacuum clutch is a type of clutch operating system that utilizes vacuum pressure for engaging and disengaging the clutch. The vacuum required for this operation is drawn from the engine’s intake manifold. Once a vacuum is generated within the intake manifold, it flows through a non-return valve and is stored within a vacuum reservoir.

This system functions automatically, engaging and disengaging the clutch when the driver shifts gears while driving the vehicle. The key advantage of utilizing a vacuum clutch system lies in the reduced effort required to operate the clutch.

⭐ Learn More – What Is Positive Clutch?

Parts of Vacuum Clutch

1. Engine Intake Manifold

The engine intake manifold is responsible for supplying vacuum pressure to the vacuum reservoir. Within an internal combustion engine, during the suction stroke of the piston, a vacuum is generated in the intake manifold. This vacuum is then directed to the vacuum reservoir, where it is stored until needed.

2. Non-Return Valve (NRV)

The non-return valve (NRV) functions as a one-directional valve, allowing the vacuum to flow from the manifold to the reservoir. When the manifold pressure exceeds the vacuum reservoir pressure, the NRV closes, effectively disconnecting the two components.

3. Vacuum Reservoir

The vacuum reservoir is designed to store the vacuum pressure that is supplied from the manifold. This stored vacuum is then used to actuate the clutch.

4. Solenoid Valve

The solenoid valve plays a crucial role in the operation of the vacuum clutch system. It is responsible for regulating the flow of vacuum pressure from the vacuum reservoir to the vacuum cylinder. The system is powered by the vehicle’s battery.

5. Switch

The switch is used to control the flow of power to the solenoid valve. Connected to the gear pedal, the switch is activated when the driver presses the pedal and deactivated when the pedal is released.

6. Vacuum Cylinder

The vacuum cylinder contains pistons that are essential to the operation of the clutch system. The cylinder has a vent to the atmosphere, which means that one side of the piston is exposed to atmospheric pressure.

7. Piston Rod

The piston rod is connected to the pressure plate of the plate-type clutch. When the piston moves to the left, the pressure plate also moves to the left, compressing the spring and releasing the pressure on the friction plate. This results in the clutch being disengaged. Conversely, when the piston moves to the right, the pressure plate moves with it, expanding the compressed spring and reapplying pressure to the friction plate. This action effectively reengages the clutch.

⭐ Learn More – What Is Diaphragm Clutch?

Working of Vacuum Clutch

The vacuum-operated clutch system operates in the following manner for engaging and disengaging the clutch:

DISENGAGEMENT

When the vehicle is in motion, the clutch is in an engaged position. When the driver depresses the gear pedal, the switch is activated and the solenoid receives power. As a result, the solenoid moves upward.

The upward movement of the solenoid connects the vacuum cylinder to the vacuum reservoir. As a result of the vacuum pressure on the left side of the piston, the piston moves (attracts) towards the left side because the atmospheric pressure is higher than the vacuum pressure.

As the piston moves towards the left side, the pressure plate also moves towards the left side, thereby releasing the pressure on the friction plate. This allows the friction plate to release from the flywheel, resulting in the disengagement of the clutch.

ENGAGEMENT

When the driver releases the gear pedal, the switch turns off, and the power supply to the solenoid valve is cut off. The solenoid then moves to a downward position.

As the solenoid moves downward, the vacuum reservoir is disconnected from the vacuum cylinder. Consequently, both sides of the piston have atmospheric pressure, and the piston returns to its original position. As the piston returns to its original position, the pressure plate moves towards the right side with the expansion of the compressed spring, resulting in the engagement of the clutch.

⭐ Learn More – What Is Hydraulic Clutch?

Advantages of Vacuum Clutch

1. Less effort is required to operate the clutch.
2. Smooth and gradual engagement of the clutch.
3. It eliminates the need for mechanical linkage between the clutch pedal and the clutch.
4. The system is automatically activated when the driver shifts gears while driving, making it more convenient for the driver.
5. The vacuum clutch is less prone to wear and tear, which makes it more reliable and durable.
6. The vacuum clutch system can be integrated with other systems in the vehicle, such as the engine control system, to improve overall vehicle performance.

⭐ Learn More – What Is Semi Centrifugal Clutch?

Disadvantages of Vacuum Clutch

1. The vacuum clutch system may require more maintenance than other types of clutch systems, especially if the non-return valve or vacuum reservoir becomes clogged or damaged.
2. The vacuum clutch system may be more complex and expensive to manufacture and install than other types of clutch systems.
3. The vacuum clutch system may not be suitable for all types of vehicles or driving conditions, especially in high-performance or heavy-duty applications.
4. The vacuum clutch system may not provide as much control over the engagement and disengagement of the clutch as other types of clutch systems, which may be a disadvantage in certain driving situations.
5. The vacuum clutch system may be less responsive than other types of clutch systems, which may be a disadvantage in certain driving situations, such as racing or emergency maneuvers.

Applications of Vacuum Clutch

1. Vacuum clutch systems are commonly used in some types of vehicles, such as trucks, buses, and heavy equipment, due to their ability to handle heavy loads and provide reliable engagement and disengagement of the clutch.
2. Vacuum clutch systems are also used in some high-performance and racing vehicles, where they can provide a smoother and more consistent engagement and disengagement of the clutch than other types of clutch systems.
3. Vacuum clutch systems are sometimes used in hybrid and electric vehicles, where they can be used in conjunction with regenerative braking systems to help recharge the vehicle’s batteries.
4. Vacuum clutch systems are sometimes used in agricultural and industrial machinery, such as tractors and combine harvesters, where they can help provide smooth and precise control over the vehicle’s speed and power.
5. Vacuum clutch systems may also be used in some other types of machinery or equipment, such as pumps, compressors, and generators, where they can help control the power output and improve efficiency.

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