Is it really that fragile? How long does a dry dual clutch last?


When it comes to the life of a dry dual clutch gearbox, it starts with its structure. Generally consumers say that the life of the dual clutch transmission actually refers mostly to its clutch friction plate life, because compared to the transmission case, the life of the clutch is much shorter, and when a failure occurs, it is usually the clutch that fails. According to the use of conditions, the dry dual clutch transmission on the market can be used for 5-10 million kilometers, with serious congestion in the car environment is likely to have problems between 30-50,000 kilometers, if the conditions are relatively smooth can also have a life of more than 100,000 kilometers.


Function of the clutch

As mentioned above, the life of the clutch is shorter for dual clutch transmissions than for gearboxes, so let's discuss the structure of the clutch here. Automatic transmissions (AT) and some Continuously Variable Transmissions (CVT) use a hydraulic torque converter, which transmits power through hydraulic coupling without mechanical separation and combination, while manual transmissions and dual clutch transmissions use a friction plate The manual transmission and the dual clutch transmission use the form of friction plate pressure plate to transmit power, and the clutch will separate the connection of the engine transmission during the shift process, and then combine the two after the shift is completed, in order to match the speed corresponding to the corresponding gear ratio. In addition, static start and ejection start are also a kind of action from clutch separation to combination.


So what is the difference between clutches?

Let's first clarify the two types of clutches.

Friction clutch

Dry friction structure refers to the clutch that does not rely on lubricating oil cooling, the friction plate (clutch plate) and pressure plate in the process of combining with the engine flywheel or semi-linkage will generate a large amount of heat, this part of the heat is all by natural wind away. This clutch is actually widely used, MT manual transmission and AMT electronically controlled mechanical automatic transmission with this type, the reason is that this design is simple in structure, low cost, and simplifies the components involved in power separation, combination, so that the power transfer more efficient (yes, dry clutch transmission efficiency is higher than wet clutch).


Because the manual transmission (MT) is decided by the driver to shift frequency and half-linkage time, the power combination is completely controlled by the driver, so the manual transmission clutch can "subjectively" reduce the number and degree of wear, here, we must mention the half-linkage.


Semi-linkage is mainly operated when the vehicle starts to accelerate slowly. Under this condition, the flywheel and clutch pressure plate are not fully connected, and the flywheel speed is much higher than the clutch output shaft, so that the engine power is partially transferred to the output shaft through the sliding friction between the flywheel and pressure plate. Half linkage is needed because the starting speed is very low, and the output power is lower than the driving resistance at this time; if the clutch is fully combined it will force the engine to stop (stall) because the resistance is greater than the power. If you want to start normally, you have to offset the driving resistance of the drive train by slipping the clutch, and the torque output of the flywheel will be reduced, but you can start normally after slowly building up power.

Here we can see that the semi-linkage is a sliding friction between the clutch pressure plate and the flywheel, which generates a lot of heat in the process and also loses the clutch pressure plate and flywheel. Therefore, experienced drivers will try to reduce the time of half-linkage or let the half-linkage happen in the area of very low speed.


In order to achieve smooth acceleration, the DCT dual clutch transmission requires a long time of semi-linkage during acceleration; in urban congestion, the vehicle is in low-speed creep or 1st and 2nd gear switching for a long time, so the wear and tear on the clutch can be imagined.

Unless the majority of the time the road is clear, the number of shifts and half linkage can be reduced, which is an effective way to reduce the wear and tear to extend the clutch life.

Wet Multi-Disc Clutch

The clutch pressure plate is divided into multiple groups, and the clutch plate is pressed and relaxed through hydraulic control to achieve power transmission and interruption, and such a clutch is generally called a wet multi-plate clutch. It increases the oil channel oil hole in the main shaft, and the clutch can scatter the transmission oil to the clutch friction plate through centrifugal force when it rotates at high speed, which can effectively realize lubrication.


Secondly, the transmission fluid also has the ability to absorb heat and dissipate heat, which can reduce the clutch friction plate temperature and reduce wear in low-speed driving and other conditions of low efficiency of the collision wind. Generally, wet dual clutch transmission has a service life of well over 200,000 kilometers, almost as long as the use cycle of the car. And compared to the dry dual clutch, it is also better stability of power transmission, placed in the performance car can achieve high RPM ejection start, reduce the role of the shift gap.


Can't I buy a dry dual clutch?

The current family car market generally uses wet dual clutch as well as AT and CVT transmissions instead of dry dual clutch. Generally speaking a car will always have a non-dry dual clutch model, so choose wisely to avoid the pitfalls.

If the model you are looking at only has a dry dual clutch transmission, or if you want to buy a dry dual clutch transmission model for cost reasons, then you need to pay extra attention during use and don't let the clutch work under high load.

The trick is simple: leave the vehicle semi-linked less often and reduce the number of gear changes.

As mentioned above, the reason why dry dual clutch can be a problem is because the clutch is in side linkage for a long time, or repeatedly need to shift, which will make the clutch temperature too high, low speed driving and let the collision wind efficiency is reduced, the air can not take away the heat in the clutch, resulting in clutch burn failure. Then, as a car owner, you just need to avoid the above working conditions, you can extend the life of the clutch. For example: planning a good route before traveling to avoid congested roads; using manual mode when driving at low speeds to limit the number of gear shifts in the transmission; the need to be decisive when accelerating, do not contain the throttle open, so that the clutch is fully combined in a short period of time.

It should be noted that although the clutch life can be prolonged through changes in one's driving habits, the clutch friction disc will still wear out as the mileage rises, so in older dry clutch models, the owner needs to have the clutch checked in time to avoid accidents during driving.


Although the dual clutch transmission has some problems, but its advantages in transmission efficiency, shift speed is almost irreplaceable, a good dual clutch transmission can let the driver experience the fist to flesh power transmission feeling, but also can effectively reduce fuel consumption, improve the use of economy. After that, the car uncle will inventory a few excellent dual clutch transmission, to need to buy a car partners to do a reference.