What are they and how do they work?
Clutches: what are they and how do they work?
A clutch is not just the pedal on the left that you need to push when you change gears on a manual car. That’s just the clutch pedal, and it is linked a complex, vital piece of equipment that performs its job thousands of times each month, and yet is hardly ever given a second thought by most of us.
So, what is a clutch?
Essentially, a clutch transmits power from the engine via the flywheel to the transmission, and is used to disengage the power from the engine to the gearbox so that you can safely change gear without damaging the gearbox.
In simple terms, a clutch is made up of a high-friction plate that is pushed against the flywheel of the engine by a spring. When you push the clutch pedal, you are pushing the clutch plate away from the flywheel so that the engine’s power no longer goes through the plate to the gearbox. When you release the clutch pedal, the clutch plate once again is pushed up against the flywheel. It then spins at the same speed as the flywheel and transmits the power back to the transmission.
Once you understand this, you realise why you should treat your clutch gently, slowly releasing the pedal to re-engage the clutch. If you release the pedal quickly (also referred to as ‘dropping the clutch’), the clutch plate bangs into the flywheel and must instantly reach the same speed. This can cause damage to the clutch and even the transmission.
Then there’s ‘slipping the clutch’. This is a bad, potentially damaging driving habit where the clutch is released too slowly, so that the clutch plate and flywheel merge very slowly. While this reduces strain on the transmission system, it increases wear on the friction surface of the clutch plate, as the clutch skims over the flywheel for a short while before engaging. This causes a build-up of heat and increased wear and tear.
Another habit that needs to be discussed is ‘riding the clutch’. This is where drivers constantly engage and disengage the clutch when waiting at an intersection, instead of stopping the vehicle and using the brake or hand brake to remain stationary. This is essentially the same as slipping the clutch.
When you understand that depressing the clutch pedal pushes two plates apart, and releasing the pedal brings them back together, you can begin to improve your driving technique and therefore reduce wear and tear on your vehicle.
For a more in-depth explanation of a clutch and normal operation, watch this great video by Popular Mechanics: https://www.popularmechanics.com/cars/car-technology/a14745517/how-car-clutch-works/.