I'm worried when I see the dual clutch, I'm annoyed when I look at the CVT, is the AT gearbox really so good?

Source: understand the car (id: idongche), understand the car and understand you better!

Author: A-Zhe; Please bring the above information to be regarded as automatic authorization

I remember 20 years ago, when I was still living in the allocated room of my father's unit, and the area near the unit was basically engaged in auto repair, and at that time, the signboard in front of almost every store said "Hand Wave Change Automatic Wave". Indeed, at that time, automatic cars were just emerging, and many cars still used manual transmissions, especially Santana and Jetta, which ran more on the road, and it was very popular to change automatic transmissions.

Today, automatic transmissions have basically become the standard configuration of modern cars, and even cars with tens of thousands of yuan are equipped with automatic transmissions. However, automatic transmissions are also divided into several different forms, such as AT transmissions, CVT transmissions and dual-clutch transmissions. Japanese family cars like to use CVT gearboxes the most, and many models of self-owned brand family cars are equipped with dual-clutch transmissions, and most of Volkswagen's brands are also equipped with dual-clutch.

Many fans said that they were worried about the fault when they saw the dual clutch, and they were annoyed when they saw the CVT, but the car with the AT gearbox is more expensive, so it is good to ask the brother. In fact, I think that each gearbox has its different advantages and disadvantages, and we still need to understand the different characteristics of different gearboxes. Not to say that dual-clutch must be "poor students", AT must be "aristocratic", in fact, many performance cars use dual-clutch gearboxes, such as the famous PDK gearbox equipped with Porsche 911, which is essentially a dual-clutch gearbox, and AMG GT is the same.

Today, let's talk about AT, CVT and DCT gearboxes, their advantages and disadvantages.

AT gearbox  

AT gearbox is currently the type of gearbox that most car buyers prefer, but AT gearbox generally appears on higher-priced models, although there are now some models below 150,000 yuan, but the total amount is still relatively small. This is because almost all the patents of the AT gearbox are in the hands of BorgWarner in the United States, and the world's well-known suppliers are ZF of Germany and Aisin of Japan. Due to the comprehensive technology and patents mastered, other manufacturers will encounter more technical barriers and pay patent fees when they want to develop and produce AT gearboxes. Therefore, most models equipped with AT gearboxes choose to purchase directly with these two companies, and the cost will naturally be pushed up.

Advantage: The AT gearbox uses a mechanical combination of planetary gears, which is more stable and can withstand the higher torque output of the engine. In addition, the AT gearbox has a torque converter, which can buffer the shock and vibration caused by the engine, so the shifting action is smooth and linear, and the AT gearbox has a peristaltic function, and the vehicle has a better experience at low speeds.

Disadvantages: First of all, the transmission efficiency of the AT gearbox is relatively low, which is also because the engine power needs to be transmitted to the size group through the torque converter, so part of the power will be "unloaded". That's why automatic transmissions consume more fuel than manuals, but are less efficient. Secondly, the structure of the AT gearbox is relatively complex, so when there is a failure, the maintenance cost will be relatively high.

CVT gearbox  

CVT gearbox is a continuously variable gearbox, in fact, from low speed to high speed range, it does not have shifting action, and CVT's so-called shift and setback are simulated by computer. Many Japanese family cars are mostly equipped with CVT gearboxes, which are also related to their national conditions, first of all, the internal structure and manufacturing cost of CVT are lower than that of AT gearboxes, and more importantly, CVT gearboxes perform smoother and more fuel-efficient. You must know that fuel saving is a point that everyone focuses on in Japanese cars.

Advantages: The advantages of CVT gearboxes have been summarized in the previous paragraph, that is, fuel saving, smooth, and low cost. In fact, this aspect is also particularly important for family cars, daily driving is fuel-efficient, driving smoothly, the price is more advantageous, for family cars that are not used for rough work, it is itself a more suitable product.

Disadvantages: Since the main structure of CVT is two conical wheels plus a steel belt connected in the middle, the steel belt responsible for transmission has become the biggest disadvantage of CVT. With the increase in usage, the transmission capacity caused by the wear of the steel belt is reduced, and the steel belt cannot withstand the high torque output, which are the disadvantages of CVT. In addition, when accelerating sharply, the noise and power output of the CVT transmission are also its disadvantages.

DCT (Dual Clutch) gearbox  

Finally, let's talk about the dual-clutch gearbox that makes everyone feel a headache, which is also the most common type of gearbox used in many independent brands and Volkswagen's brand models. Why don't domestic brands purchase ready-made AT gearboxes? The main reason is that the price is expensive, the second is that it is easy to be "stuck in the neck" of suppliers, if you encounter competitors sanctions, increase the supply price or stop supply, then the car company will have the risk of stopping production. In order not to call fate into the hands of others, dual-clutch gearboxes have become a way out under the compromise of many independent brands.

Advantages: The advantages of dual-clutch gearbox are outstanding, with fast shifting speed and high transmission efficiency, and the shifting time can be completed in only 0.1-0.2 seconds. As a result, the experience is better when driving intensely, and there is less loss of power output. Secondly, the dual-clutch transmission structure itself is very close to the manual gearbox, so the structure is simple and the manufacturing cost is relatively low. That's why many performance cars are also equipped with dual-clutch transmissions.

Disadvantages: long-term low-speed creeping, clutch in a semi-linkage state, extremely prone to overheating, especially dry dual-clutch gearbox, sometimes long-term traffic jams, there will be fault lights or even abnormal transmission noise. That's why everyone talks about dual-clutch color change. Secondly, the frustration of shifting gears is more obvious, especially in the case of one foot of the accelerator and one foot of the brake, frequent gear changes can obviously feel the sudden setback of the dual clutch. Therefore, it is recommended to choose wet dual clutch, try to choose wet type, there is oil inside, which is more helpful for frustration and heat dissipation.

However, as for the dual-clutch gearbox, I think it is more important to pay more attention to the manufacturer's calibration and tuning, and some car companies deliberately slow down the shifting action because the dual-clutch gearbox is not well tuned and want to avoid obvious setbacks. I personally don't like this kind of tuning very much, driving a car with protracted gear shifts and unintelligent shifting logic, it really feels uncomfortable to drive.

For the different types of transmissions, in fact, I don't think it is necessarily bad to say which kind of gearbox is equipped with a car, or which one can only be bought. Different gearboxes have different advantages and disadvantages, but what is more important than these depends on the gearbox tuning logic of the vehicle. A gearbox with chaotic shifting logic and poor tuning will not only feel uncomfortable for drivers, but also for passengers. Be sure to test drive before buying a car! This is very important!