How does a clutch work?

How does a clutch work?
There are many components that make a vehicle drive, and one of the integral parts is the clutch. But what is it? And what does it do?

Whether you drive an automatic or manual vehicle, the clutch is integral – and something that will be checked in a full service.

However, most drivers will be unsure how it works – and this guide is here to help.

What is a clutch?

A car clutch is the mechanical device used in manual transmission engine, which engages and disengages the power transmission between the engine and the gearbox.

It allows a driver to shift gears while the engine is running is a smooth and efficient way.

The clutch consists of several components within the engine, including a clutch pedal, clutch disc, pressure plate, sensors, and a flywheel. Some clutch systems involve other parts – especially in higher spec models.

When the clutch pedal is pressed, it disengages the clutch by separating the clutch disc from the flywheel.

This interrupts the power flow from the engine to the gearbox, allowing the driver to change gears.

Without this, the engine would stall, and the vehicle would come to a stop.

When the clutch pedal is released, the clutch engages, allowing power to transfer from the engine to the gearbox.

This allows to the driver to safely accelerate or slow the vehicle down.

It is vitally important for a driver to keep up with regular maintenance of the clutch system. Not doing so will lead to a costly repair bill.

How does a clutch work?

The use of a car clutch involves several mechanical components working together to engage and disengage the power transmission between the engine and the gearbox.

Here is a step-by-step guide on how a clutch works:

  1. Engage clutch pedal: Push the pedal on the left with your left foot to start the process.
  2. Clutch disc: When the clutch pedal is pressed, the pressure on the clutch disc is released, allowing it to move freely.
  3. Pressure plate: This is mounted on the flywheel and exerts pressure on the clutch disc when the clutch pedal is released. It creates friction and transfers power from the engine to the gearbox.
  4. Flywheel: A flywheel is the rotating surface used for the clutch disc and pressure plate to engage. It helps continue the momentum of the engine when the clutch is disengaged.
  5. Changing gear: In a manual car, the driver can now use the gearstick to change gears up for down.
  6. Disengage clutch pedal: When the clutch pedal is released, the pressure plate re-engages the clutch disc against the flywheel, allowing power to transfer from the engine to the gearbox and ultimately to the wheels, propelling the vehicle forward.

In an automatic vehicle, this process is done for you by the engine ‘automatically’ – however, there are still gears in place.

If this process isn’t smooth and efficient, then it is likely that there is an issue with your gearbox or another part of the engine.

Drivers who are experiencing any issues, should visit a local garage or call a mobile mechanic to sort the problem.

Also, avoid riding the clutch and aggressive driving to help prolong its lifespan of the system and avoid any unnecessary wear and tear.

What are the different types of clutches?

There are several types of car clutches, which are designed for specific type of vehicles.

The types of clutches include, friction clutch, centrifugal clutch, semi-centrifugal clutch, hydraulic clutch, and cone clutch.

Here is what they are and what makes them different:

Friction clutch

This is the most common type of clutch found in manual vehicles today.

It uses a clutch disc lined with friction material sandwiched between the flywheel and pressure plate. When engaged, the pressure plate applies force to the clutch disc, allowing power to transfer from the engine to the gearbox. When disengaged, the pressure plate releases the clutch disc, interrupting the power flow.

Centrifugal clutch

Although they are more common in small motors (often not in vehicles), these are seen in motorbikes and microcars. When the engine rotates, centrifugal force causes the clutch pads to move outward, engaging the transmission. This transfers power from the engine to the transmission through centrifugal force. This means that when the vehicles slows down, the centrifugal force decreases, causing the clutch pads to disengage with the clutch.

Semi-centrifugal clutch

Similar to the fully centrifugal clutch, however, the semi uses additional features for manual control of clutch engagement. Semi-centrifugal clutches allow drivers to manually override the automatic engagement of the clutch. This is common in many off-road vehicles.

Hydraulic clutch

These clutches use hydraulic fluid to transmit force from the clutch pedal to the clutch mechanism, instead of a mechanical linkage. There are many variations of this clutch in all types of vehicles.

Cone clutch

These are common in automatic vehicles. It consists of two conical friction surfaces, one mounted on each shaft, which can be pressed together or pulled apart to transmit or interrupt power. The gear change is done ‘automatically’ by the engine when the revs increase or decrease.

What does ‘riding a clutch’ mean?

Riding the clutch refers to when a drivers pushes down on the clutch pedal for an extended period of time while driving.

It can also refer to when even slight pressure is applied to the pedal.

Drivers who ride the clutch use this tactic to slow the vehicle down slowly without shifting gear.

However, this can have a negative impact on the vehicle, by wearing out the clutch, building up excessive heat to the engine, and reduced fuel efficiency.

It also impact the performance of the vehicle – both while riding the clutch and when releasing the clutch peddle after a period of time.

Common car clutch problems

There are many common car clutch problems that can arise due to various reasons.

Aside from wear and tear over time, and wider issues with the gearbox and engine, there are several things drivers should keep an eye on.

A likely issue is when the clutch is slipping. This happens when the clutch fails to fully engage after the driver releases pressure on the clutch peddle. This causes a loss of power and can damage everything within the clutch system.

This can also be known as dragging the clutch, which causes a loud grinding noise when a driver tries to change gear.

If there is uneven wear on the clutch plates or pads, your vehicle will start to jerk and shake when you try to reengage the vehicle.

In hydraulic clutch systems, there is a common problem of fluid leaks or air bubbles being trapped in the system. The vehicle will shake and make a loud clicking sound. A driver will also struggle to change gears.

Other common problems include issues with the clutch pedal, such as stiffness, sponginess, or a pedal that sticks to the floor.

No matter the problem, the best course of action is to take your vehicle to a local garage or to contact a mobile mechanic.

How much does a new clutch cost?

If you are in a situation where you need a new clutch, here is what you could expect to pay.

  • Small car – £400-£600
  • Medium car – £500-£700
  • Large car – £600-800
  • Premium car – £800+

These prices include the cost of any work that could be carried out by a mechanic.

However, drivers should be aware that if your clutch needs replacing, then it is likely that there could be other issues. These can odd up the cost significantly.

MORE: Clutch replacement costs - all you need to know

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