Vacuum clutch: What is it, Diagram, Construction, Working, Advantage [with pdf]

What is Vacuum clutch?

1] Vacuum clutch is the clutch operating system that uses the vacuum for the operate engagement and disengagement of the clutch.

2] The vacuum used for this operation is taken from the engine intake manifold. When a vacuum is created inside the intake manifold, It flows through a non-return valve and is stored inside the vacuum reservoir.

3] This system automatically operates when the driver shifts the gear which means during running the vehicle when the driver shifts the gear, The system gets on and disengages the clutch.

4] The advantage of using a Vacuum clutch is that less effort is required to operate the clutch.

Vacuum clutch diagram

Vacuum clutch
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Vacuum clutch
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Vacuum clutch
Vacuum-clutch-position

Construction

Vacuum clutch is consists of the following key components:-

1) Engine Intake Manifold:- It supplies the vacuum to the vacuum reservoir. In an internal combustion engine, During the suction stroke of the piston, a Vacuum is created in the intake manifold.  Hence Vacuum from manifold supply and stored to Vacuum reservoir.

2) Non-Return Valve ( NRV):- It is a one-directional valve. Vacuum from manifold flows through a Non-return valve to vacuum reservoir.

When manifold pressure increases than vacuum reservoir pressure, the Non-return valve closes. hence both are disconnected.

3) Vacuum Reservoir:- Vacuum reservoir stores the vacuum that comes from the manifold. Vacuum from vacuum Reservoir is used to actuate the clutch.

4) Solenoid Valve:- It is used to Start/Stop the flow of vacuum from vacuum reservoir to vacuum cylinder. The battery is used in the system to supply power to the solenoid valve.

5) Switch:- Switch is used to Start/Stop the power supply to the solenoid valve. The switch is connected to the gear pedal.

When the driver presses the gear pedal, Switch gets on & when the driver releases the gear pedal, the switch gets off.

6) Vacuum Cylinder :- It is consists of pistons. Vent to the atmosphere is provided to vacuum cylinder, hence piston has atmospheric pressure on one side.

7) Piston Rod:- Piston rod is connected to the pressure plate of the Plate type clutch.

When the piston moves towards the left side, the Pressure plate also moves towards the left side, against compressing spring.

Hence Pressure on the friction plate removes, so the friction plate releases from the flywheel therefore clutch gets disengage.

When the piston moves towards the right side, the Pressure plate also moves towards the right side with the expansion of the compressed spring.

Hence pressure plate again presses the friction plate against the flywheel therefore Clutch gets Engage.  

Vacuum clutch working

The vacuum-operated clutch working for engagement and disengagement of clutch is as follows:-

DISENGAGEMENT:-

When a vehicle is running, the clutch is in the engaged position. Therefore when the driver presses the gear pedal, the switch gets on & the power supply starts to the solenoid. Hence solenoid moves upward.

Due to the upward movement of the solenoid, the Vacuum reservoir is connected to the vacuum cylinder. Due to the vacuum on the left side of the piston, the Piston moves (attracts) to the left side because atmospheric pressure is greater than vacuum pressure.

When the piston moves to the left side, the pressure plate also moves the left side, Hence the pressure on the friction plate removes, so the friction plate releases from the flywheel, therefore, the clutch gets Disengage.

ENGAGEMENT:-

When the driver releases the gear pedal, the switch gets off & the power supply stops at the solenoid valve. Hence solenoid comes to a downward position.

Due to downward movement of the solenoid, the Vacuum reservoir is disconnected to the vacuum cylinder & now from both side piston have atmospheric pressure. Hence due to this piston returns to the original position, When the piston returns to the original position, the Pressure plate also moves towards the right side with the expansion of the compressed spring. hence clutch gets Engage.

Advantage of vacuum clutch

The vacuum clutch has the following advantage

1] less effort is required to operate the clutch.

FAQ on vacuum clutch

  1. What is vacuum clutch?

    Vacuum clutch is the clutch operating system that uses the vacuum for the operate the engagement and disengagement of the clutch.

  2. How does a vacuum clutch work?

    The vacuum clutch works using a vacuum. Vacuum clutch is the clutch operating system that uses the vacuum for the operate engagement and disengagement of the clutch.

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Pratik is a Graduated Mechanical engineer. He enjoys sharing the engineering knowledge learned by him with people.

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