Clutch, How does it work ?

Have you, ever wondered what is happening inside a car, when you press the clutch pedal Or, why, do you need, to press the clutch pedal before you shift gears in a manual transmission car This, video gives you, logical answers to these questions At the end of the video we will, also understand the crucial role played, by the clutch in an uphill start To, understand the need for a Clutch let’s first understand the anatomy of an internal combustion engine car Internal combustion engines have a very limited torque band and Due to this reason in order to efficiently vary the speed of the drive wheels internal combustion engine cars need a transmission system The use of this transmission makes sure that the engine is working within its optimum rpm range and by changing gear According to the driving conditions the transmission helps to control the drive wheel speeds In a manual transmission car making these gear changes is not an easy task to have a smooth gear change with a Manual transmission the engine power flow to the transmission has to be discontinued However it is not practical to turn off the engine just for this gear change The clutch is used for this purpose in short the clutch is a mechanism to disconnect the flow of power to the transmission without turning the engine off Let’s understand how it works The main part of the clutch consists of a disc coated with high friction material on both sides a simplified clutch disc is shown here this disc sits on the flywheel if An external force presses against the clutch disc the clutch disc also will turn with the flywheel due to the frictional force The input shaft of the transmission is connected to the disc So that when an external force is applied to the disc the engine power will get transmitted to the transmission system This external force is provided by a Pressure plate spring system Cover of this system is attached firmly to the flywheel So the pressure plate will firmly press onto the friction clutch disc and the engine power will be transmitted to the transmission system But this is the case in normal driving so how is the power disengagement done with the clutch For the disengagement purpose a special kind of spring is introduced in the pressure plate Assembly, this spring is known as a diaphragm spring To understand this diaphragm spring better, assume that the diaphragm spring motion is fixed around This circle in this case if you press the center portion of the spring as shown the outer portion should move in the opposite direction The diaphragm spring sits between the pressure plate and the cover To understand this configuration better let’s take a cross-section of the assembly the outer portion of the diaphragm spring is connected to the pressure disc This means if you press the inner portion as shown the pressure disc will move away from the friction disk thus the power flow will discontinue to the transmission This is exactly what happens when you press the clutch pedal A hydraulic system transfers the clutch motion to the center of the diaphragm spring When the diaphragm spring is pressed the power flow is discontinued? During this time you can make a gear change the clutch pedal is released after the gear change and the power flow continues again This is how a clutch works In an actual clutch you can see a few coil springs on the clutch disc what’s the purpose of these springs These are used to smooth out the fluctuations and vibrations from the engine power output It is clear that the hub and disc are not directly connected The engine power first reaches the disk then it transfers to the springs and finally to the output hub This means that the springs will dampen out most of the power flow Fluctuations from the engine and the motion transferred to the vehicle will be much smoother Now, let’s explore an extremely important and difficult task in driving cars with manual transmission starting from uphill Even in a car without a handbrake you can use this clutch technique to start, while pointing uphill In an uphill start initially both the brake and clutch pedal are pressed, while the engine is running Now, release the clutch pedal partially until you feel the clutch bite The clutch bite can be experienced at. Your foot it may feel like the engine is shivering at This point even if you release the brake pedal you can see the vehicle will not roll the Partially released clutch acts like a brake now You can press the gas pedal and the car will move forward The big question here is how does the partially release clutch act like a break This break phenomenon is nothing but a game of force balanced in a perfectly forced balanced condition the vehicle Wheels will not be able to roll and the gravitational pull will be the same as static frictional force at the wheels The vehicle wheels are prevented from rolling by another force balance Force balance between the engine forward force and the same static frictional force When you partially release the clutch and it balances for the clutch bite you are unknowingly doing all these force balances When these forces are in perfect balance the wheels the transmission system and the clutch disk will not be able to spin This is how the clutch bite acts as a brake but remember the frictional force between the rubbing surfaces Produces the engine forward force in this case this will result in wear and tear of the friction material on the clutch disc We hope this video will enable you to be a better engineer and a better driver Please support our educational activities at and don’t forget to subscribe thank you

100 thoughts on “Clutch, How does it work ?”

  1. Hello friends, wish you a happy New Year ! I hope you can make a new New Year resolution at 🙂 Long live free education !

  2. Me : not knowing anything about car mechanics

    Youtube : puts this video in my recommended

    Also Me : …sure why not

  3. I prefer manual because I learned to drive in one. Also you have more control of the vehicle. Any monkey can steer an auto. It takes a driver to operate a manual.

  4. Watching this as someone from main land Europe it is funny you hearing to say that an up hill start is an extremely difficult task. Especially since 98% of Dutch people learn to drive a manual gear car haha. Bravo tough for the explanation about friction material wear. Very little people now this. It’s the same reason why clutch launches are very harsh on your car. Both the clutch gears as well as the friction disk get a real hammering when performing launch control…but it is so fun to do…even in a manual car haha

  5. oh wow, a beamer that didnt break down, nor wheelspin when doing a hillstart

  6. شكرااا جزيلا.. استعنت بالترجمة إلى العربية و فهمت كيف يعمل

  7. Rent a Slingshot for 24h, learned Manual transmission on the go, 24 h later, i drive manual without stalling, and now i'm back to automatic and damn it suddenly got boring to drive it, with my left feet hitting an clutch that does not exist each time i come to a red light XD

  8. Creativity technical engine gear and engine stroke power transmission and connect rod transmit cam shaft in linear motion on this rotational wheel MECH BRILLIANT MIND

  9. Thanks for uploading such an educational video. I am positive that this will help millions of people, including myself, who are engineering enthusiasts.

  10. I am teaching my son how to drive standard. This video is a perfect explanation of how a clutch system works!

  11. My car's gears have jammed. They change only when the car is off, as soon as I start my car, the gears won't change. What might be the possible reason for that? Also, my car was stuck in a puddle few days back, and the water entered in the car, I doubt water entered the gear box. Please help

  12. Believe me I am not an engineer nor a driver
    And my dad's car clutch is not hydraulic it is wired and uncomfortable that makes my dad's foot get hurt every time he drive it.

  13. Can we take a minute to talk about why the serpentine belt was on the back of the engine, never let the person who designed this video engineer a car.

  14. That's the old system, some cars don't have the springs on the clutch disk,neither the flywheel is the single mass anymore,diesels mostly use dual mass flywheels due to high torque.

  15. This is why we learn physics in class but only a few would turn up to be a real physicist.. Because it literally mind blowing..

  16. So from what I understand, when I want to start riding uphill, I can use the clutch to simulate the break, but it shouldn't be used too often as it can damage the car's internal parts?

  17. I have a doubt on the placing of clutch plate, the force given to the pressure plate will pull the clutch plate and release it from the flywheel. Is it correct? If it is correct then the clutch plate will fixed with flywheel

  18. Hey, when i was in school, my instructor always taught me (diesel car) to start uphill using the technique shown here, but my question is, doesnt this wear out the clutch fast ?

  19. Not an engineer but I now fully understand what’s going on when I use the clutch pedal, so basically the clutch disk takes more punishment when is partially holding the car with a balance of the engine force. I thought that this grinding occurred also when the clutch was fully pushed.

  20. Is clutch bite can hold the vehicle in stationary without the engine dying out? I often find myself pumping gas to make it stationary. ..

  21. Don't need to use a clutch except for stopping and starting (actually only starting) if one knows how to shift going by the rpm's appropriately…

  22. i still don't understand what happens at the clutch during the uphill start. if the disc either connects the engine to the shaft or disconnects, how does the partial force transmission happen?

  23. Very unique car design, I have never seen a rear facing engine, in the 8 years of being an ASE Technician or 6 years as an Engineer. Must be difficult to change the belts!

  24. Um I wouldn’t do that on a hill because the friction will cause premature wear of the clutch. Better to have quick feet and get used to timing it. If you have a hand brake it is easy because all you need to do is hold the car with the hand brake and release it at the same time you are releasing the clutch and applying gas. Subarus have a bill holder feature for al cars but it especially works well with manual transmissions.

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