Why is a dry dual clutch bad? What are the disadvantages of dry dual clutch transmission

The reasons why dry dual-clutch is bad are:

1. There are deficiencies in heat dissipation, which is not suitable for frequent starting, long-term low-speed driving or stop-and-go, clutch overheating, and even failure;

2. Because the hydraulic torque converter is not used, and the semi-linkage action of the manual transmission cannot be realized, for the engine with small displacement, the dry dual clutch will expose the insufficient torque at low speed.

Clutch engagement process.

The clutch engagement process can be divided into 4 stages:

The first stage is used to eliminate the empty displacement between the main and auxiliary friction discs of the clutch, and there is no torque transmission.

In the second stage, friction occurs between the main and auxiliary friction discs of the clutch, but the torque transmitted by the clutch is not enough to overcome the drag torque experienced by the car, and the vehicle remains stationary. At this stage, the friction is intense, and the slip grinding work increases sharply, and this stage should be completed as soon as possible.

In the third stage, the torque transmitted between the main and auxiliary friction discs of the clutch begins to be greater than the resistance torque of the car, and the car begins to move, and the change of the transmitted torque between the main and auxiliary friction discs of the clutch at this stage will cause impact, in order to achieve a smooth start, this stage should be completed relatively slowly, but too long time will also increase the slip grinding work, affecting the service life of the clutch.

In the fourth stage, the main and auxiliary friction discs of the clutch begin to be synchronized, and the engagement speed has no effect on the slip grinding work and impact.

In fact, whether it is a dry clutch or a try clutch, it is afraid of rain, but normal manufacturers have rain-proof functions when designing, so there is no need to worry too much.

The main problems are:

1. Because the hydraulic torque converter is not used, and the "semi-linkage" action of the manual transmission cannot be realized, for the small displacement engine, the characteristics of insufficient torque at low speed will be completely exposed.

2. Because the dual-clutch adopts computer control, it belongs to an intelligent transmission, it needs to send an electronic signal to the engine in the process of upshifting and downshifting, and after the engine replies, it can cooperate with the engine to complete the upshift and downshift. The use of a large number of electronic components also increases the probability of failure.

Hello, the dry dual-clutch has deficiencies in heat dissipation, and it is because of this heat dissipation problem that often problems. This has a greater relationship with driving habits, the reason why many people buy is because the dry dual-clutch model is cheap, the wet dual-clutch within 15 is rare in China, and the advantages of the dry dual-clutch are also obvious, first of all, its manufacturing cost is lower than the wet type, and the structure is simple;

The dry dual-clutch transmission has poor heat dissipation performance, and the clutch plates are easy to overheat when in traffic jams.

There are two types of dual-clutch transmissions, one is a dry dual-clutch and the other is a wet dual-clutch. The clutch plates of a dry dual-clutch transmission are not soaked in the transmission oil, while the clutch plates of the wet dual-clutch transmission are soaked in the transmission oil.

Because the clutch plates of the dry dual-clutch transmission are not soaked in the transmission oil, the clutch plates of this transmission can only rely on the wind to dissipate heat, so the heat dissipation performance of this transmission is not good.

If driving in a traffic jam, the transmission will frequently switch back and forth between 1st and 2nd gear, which can easily cause the clutch plates of the dry dual-clutch transmission to overheat. The dry dual-clutch transmission can also withstand less torque.

The clutch collapse disc of a wet dual-clutch transmission is soaked in transmission oil. This gearbox is very reliable and stable, can withstand high torque, and the clutch plates also have good heat dissipation performance.

But the wet dual-clutch transmission doesn't shift as quickly as the dry dual-clutch transmission. The structure of a dual-clutch transmission is similar to that of a manual transmission. This gearbox only has one more clutch and a shift control mechanism than the manual transmission.

Disadvantages of dry dual-clutch

First, it is prone to high temperatures and has poor wear resistance. If you are constantly stop-and-go in congested conditions, the automatic transmission will switch back and forth between first and second gears frequently. The clutch works back and forth frequently, which can cause the clutch plate to heat up.

Especially in the summer, when the temperature is high, the temperature of the engine and gearbox is relatively high, and then the heat dissipation is not good, and the heavy load driving will aggravate the wear of the clutch.

Second, the transmission overheats and easily locks automatically. When the clutch overheats, the high temperature will be displayed, the gearbox's protection program will be activated, and self-protection will be implemented, and the car will not be able to drive. You can't continue driving until the temperature drops.

Third, the dry dual clutch will be prone to shaking or frustration after a long time. It is not obvious when it is a new car, but it will be more obvious after running tens of thousands of kilometers or 100,000 kilometers after the car is old. The moment you start driving, you can clearly feel this frustration, which is because the clutch plate is high and wears out early, and after the gap becomes larger, it is not as comfortable to drive as it was when you were in a new car.

Insufficient heat dissipation of dry dual-clutch transmissions is a common problem. It's all about driving habits. The reason why many people buy it is because the dry dual-clutch model is cheap, and it is rare to have a wet dual-clutch within 15 in China.

Methods for distinguishing between wet and dry dual-clutch transmissions:

1.Dry dual-clutch and wet dual-clutch drives are almost identical, with the main difference being the different connection media for the drive disc and the driven disc of the Thansen combinator. To put it bluntly, the working environment of the clutch plate is different.

2.The clutch plates of the wet dual-clutch are immersed in the transmission oil and rely on the oil; The clutch plates of the dry dual-clutch are in direct contact with the engine flywheel and rely on empty air;

3.Wet dual clutch has a certain heat dissipation effect due to the clutch disc working in hydraulic oil, and it is more stable to use; And because it is soaked in oil, it works by friction in a humid environment. The advantage of wet dual-clutch transmission is that it has a long service life and generally does not fail to hold the finger.

The disadvantage is that the wet dual-clutch structure is complex, the manufacturing cost is high, and the power transmission efficiency is not as good as that of the dry clutch.

4.Dry clutches have no oil cooling, heat dissipation is exposed, and heat dissipation efficiency is not as good as wet dual clutches. This is also the reason why it is easier to break. Especially when there is a traffic jam, the gearbox often has to switch between first and second gear, and the wear is very large.

Millions of car purchase subsidies.

Dry double clutch is not as bad as said, but it has a little defect, the biggest advantage of dry double clutch Yuqing is its own resistance, high power transmission efficiency, fuel saving, the defect is not conducive to heat dissipation, the start macro demolition will produce a certain slip, especially on the slope of the road section start, the maximum slip distance can reach more than 30 cm.

Dry dual-clutch disadvantages:

1. Setback: Dual-clutch gearbox has always had a different view on the setback, the response is relatively slow, whether it is in acceleration or deceleration, the dry dual-clutch gearbox seems to be a little frustrated, if it is running in 3 gears during driving, but the dry dual-clutch will match the 4th gear in advance, due to emergencies when braking, there may be a setback, which is the more common reason why many consumers give up the dual-clutch gearbox.

2. Easy to break: now many people are driving in congested urban areas, at this time the dual-clutch gearbox will generally be in a semi-linkage state, the friction between the clutches is more frequent, resulting in the gearbox heating, the probability of failure is also greatly improved, if you often run high speed, this phenomenon is not very common, consumers can choose the gearbox flexibly according to their own driving environment.

Photo by Zhang Fengxue) @2019

As far as the current situation is concerned, it is not recommended to choose a model equipped with a dual-clutch gearbox! Because so far there has not been a car brand with a dual-clutch gearbox, which has not been a problem! With the exception of high-performance dual-clutch transmissions like the Porsche PDK, no dual-clutch transmission can match the reliability and stability of conventional ATs or CVs

Dry dual-clutch good :

1, the so-called dual-clutch transmission, referred to as dct, Chinese translation should be a direct shift transmission, because it has two sets of clutches, so many people simply call it dual-clutch balance sock transmission. The principle is actually universal to the principle of manual automatic transmission;

2. It's just that the clutch of the dual clutch and AMT is operated by the computer, and the driver does not need to step on the clutch. The dual-clutch can be popularly understood as having two sets of virtual clutches, this set is in the first gear, and the other set of clutches is ready in the second gear, which is convenient for quickly switching gears;

3. Seamless gear shifting. The shift clearance of the dual-clutch transmission is very short, only about a second. Fuel efficient.

Because torque interruption is eliminated, the power of the engine is always at output, so it is maintained in the best working condition, and the fuel economy is greatly improved. Compared to conventional automatic transmissions, it can save up to 15% of fuel.

There are still problems with dry dual-clutch: 1. Although there are indeed such and such defects and problems in dry dual-clutch, it does not mean that dry-type dual-clutch can never be bought. 2. Some are dry dual-clutch, which is purely mechanical and more conducive to the track environment.

Dry dual-clutch is still problematic :

1. Although there are indeed such and such defects and problems in the dry dual-clutch, it does not mean that the dry-type dual-clutch can never be bought.

2. Some are dry dual-clutch, the pure mechanical structure shifts more quickly, which is more conducive to the track environment, and most importantly, the track environment does not need to consider the cost of car manufacturing and the stability of the car in the later stage, and speed is the only pursuit;

3. If there is an AT, will you choose a dual-clutch? For family cars, if there is an AT, the pursuit of stability and reliability, or tend to AT, Busun is currently in the field of family cars 6AT and 8AT quality is stable and reliable, few small problems, car maintenance costs are also lower;

4. The order of selection is: AT> wet dual-clutch, dry dual-clutch. However, for family cars, dry dual-clutch is not jackals and tigers and leopards, it still depends on the environment of the vertical chain car, if it is not a congested urban area, there are no traffic lights and frequent start brakes, dry dual-clutch is not impossible to buy;

5. If the budget is limited, or the model only has a dry dual-clutch option, the defects of the dual-clutch can be accepted, and the premise of the car environment support, the dry dual-clutch is not as terrifying as imagined. How often should the dry dual-clutch transmission fluid be changed.

Dry dual-clutch transmission fluid is recommended to be replaced in 60,000 km or 4 years:

1. Dual-clutch gearbox is divided into dry dual-clutch gearbox and wet dual-clutch gearbox. The principle of both dry and wet transmission is basically the same, with two clutches working in turns. However, the connection medium of the driving disc and the driven disc of the clutch is different, the dry double clutch relies on air, and the wet double clutch relies on oil;

2. Dry dual-clutch and wet dual-clutch have similarities and differences, of course, it does not mean that who is better than whom, each has its own advantages and disadvantages. The difference between a dry dual clutch and a wet dual clutch is that the two have different clutch plates working ring nucleus environment. Wet dual clutch plates refer to the clutch plates soaked in transmission fluid, while the clutch plates of dry dual clutch are in direct contact with the engine flywheel;

3. From the perspective of technical maturity and reliability, the wet dual clutch is more stable to use because the clutch plate works in the hydraulic oil, and the oil plays a certain role in heat dissipation. Because of poor heat dissipation, dry dual clutch is prone to the risk of high temperature or even ablation of clutch plates in congested urban areas. At this level, the wet dual-clutch transmission technology is more mature.

At the same time, the wet dual-clutch structure is complex, the manufacturing cost is high, and its power transmission efficiency is not as high as that of the dry type. Dry dual-clutch is not going to work @2019