Скачать или смотреть Why Dry Clutches Suck and Why You Should Avoid Dry Dual Clutch Transmissions (DCT/ DSG)

Support the channel by shopping through this link: https://amzn.to/4fatbMb
Become a member:    / @d4a  
Patreon:   / d4a  

Your clutch synchronizes the speed of the transmission to the speed of the engine. When taking off, the transmission is at 0 rpm. If you were to just suddenly dump the clutch you would expose the transmission to all the engine rpm and torque instantly, you and your passengers will jerk forward, the drivetrain gets a nasty shock, and the engine likely stalls, nobody’s happy.

However, when you release the clutch gradually the transmission rpm also rises gradually. No shocks no stalls. The question we must ask at this point is how does the clutch synchronize the engine and the transmission speed? It's just a solid object, there’s nothing special about it. The clutch achieves its goals by slipping. Clutch slipping is essentially a difference in speed between the flywheel and the clutch itself while the two are already in contact with each other. Slipping occurs whenever the friction force is low enough to be overcome by torque produced by the engine.

However, if you have ever slipped the clutch too much you have probably caught a whiff of a smell that resulted from it. This is the smell of a burning clutch. Clutch slipping is essentially the rubbing of two contact surfaces. The friction between to rubbing surfaces creates heat. So if we slip or rub the clutch against the flywheel too much we can easily increase the temperature of the surfaces to the point that they start burning.

Ok, let’s say that we want to slip the clutch burt we don’t want to burn it. How do we do that? Easy, just sink it in oil. A motorcycle clutch is precisely that. The beauty of a wet clutch is that is very difficult to burn it, even if you have very little clutch operation finesse. You can slip it repeatedly, you can dump the clutch repeatedly but there will be no nasty clutch burning smell.

Ok, now let’s say we want to step things up even further. Now let’s say that we want the ability to slip the clutch without burning it but we also don’t want to have to do the slipping ourselves. And we want lightning fast gear shifting, let’s say 8 miliseconds.

No problem! Enter the dual clutch transmission. It’s essentially your standard geared manual transmission with two input shafts and two wet clutch packs together with some mechatronics and actuators instead of a clutch pedal. A dual clutch transmission can shift faster than any human can shift a conventional manual transmission because it has two clutch packs. When you are in one gear one of input shafts is used and one the clutch packs is engaged, while the other clutch pack is disengaged but it already has the next gear pre-selected.

Ok so this is the perfect transmission? Well, that’s a subjective thing but dual clutch transmissions definitely accomplish their mission. They have a fun factor but are at the same time very convenient and easy to use while being capable of handling very high torque. Their downsides are that they are more complex and expensive and require more maintenance compared to a conventional manual. This is because clutch packs wear out because they must slip and when they slip they loose tiny particles. These particules end up circulating through the oil. This is why motorcycle oil changes color quickly. It’s the clutch particles. And so the transmission oil and filter must be changed. In contrast to this manual transmission fluid needs to be changed far less frequently, some manufacturers even claim it doesn’t need to be changed.

But as is often the case, when manufacturers make something that’s nice and that sells, they tend ask the next question and that question iiiis: how can we make more money from this.

Enter the dry dual clutch transmission. The answer to that question.

NManufacturers will tell you that they have introduced it because it is more efficient. Because the clutch packs rotate in air there’s no oil drag on them so they have an easier time rotating which contributes to an efficiency improvement of 1-3%. Because they’re more efficient the vehicle needs to use less fuel and thus they are better for the environment. In reality, dry dual clutch transmissions are not cleaner, they simply trade one pollutant for another. They reduce c02 emissions but they dramatically increase particulate matter emissions. That’s because clutch packs are not sealed. They need to be cooled by air so they have ventilation holes. At the same time as clutch packs wear they create clutch dust. This dust escapes through ventilation holes into the air we all breathe.

A special thank you to my patrons:
Daniel
Peter Della Flora
valqk
Dave Westwood
Zwoa Meda Beda
Cole Philips
Allan Mackay
Sam Lutfi
Alex

00:00 A Clutch Must Slip
04:52 How to Slip Without Burning
06:08 Wet Dual Clutch Transmissions
09:06 Dry Dual Clutch Transmissions

#d4a #dct #dsg