The AT gearbox is so good, why do domestic cars like to use dual-clutch?

19/03/2021
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If you talk about a few good gearboxes, the first thing that comes to mind should be ZF 8AT, Aisin 8AT, Aisin 6AT, Mercedes-Benz 9AT, GM 10AT, etc. Few people first think of dual-clutch and CVT, from the overall performance In terms of performance, the AT gearbox is indeed better and more stable. In this case, independent brands with weak gearbox technology should focus on excellent gearboxes. But why are there more and more dual-clutch gearboxes in domestic cars?

The AT gearbox is so good, why do domestic cars like to use dual-clutch?  (figure 1)

Although AT gearboxes are good, they cannot be developed casually. Now the patents of core technologies are almost monopolized by some gearbox giants. Not to mention paying the patent fees according to their route, in the end, the core technology may still be in the hands of others. If you want to do your own research and development, you must bypass these patents. The difficulty will be greatly increased. After paying high research and development costs, you may not be able to successfully develop them. Therefore, it is normal not to research on AT gearboxes.

The AT gearbox is so good, why do domestic cars like to use dual-clutch?  (figure 2)

Furthermore, the CVT also has great shortcomings. Although the structure is not complicated, the adjustment of the transmission needs to be more precise. Unlike other gearboxes, there is no fixed gear, and it is not that a certain speed range corresponds to a certain gear. If you want to adjust The calibration needs to be accurate to each point of the corresponding relationship between speed and gear ratio, especially to test the level of adjustment. Moreover, the insufficient torsion resistance of the CVT gearbox will directly affect the matching with large-displacement engines. For example, the current 2.0T engine rarely matches the CVT, which will greatly limit the development of domestic cars to high-end.

The AT gearbox is so good, why do domestic cars like to use dual-clutch?  (image 3)

Therefore, after comprehensive consideration, although the dual clutch has shortcomings, it is relatively the most suitable choice. The structure is also not complicated, the patent protection is not so much, the adjustment is relatively simple, and the torsion resistance can be continuously upgraded. It will not affect the matching of high-torque engines in the future. As long as the technology is continuously improved, the shift logic will become more and more mature, and the reliability will be further improved. Just like when the application was first developed, there were indeed a lot of problems, but now the corresponding quality is getting better and the failure rate is getting lower and lower. There have been achievements in the research and development of automatic transmissions in domestic cars. With the accumulation and continuous progress of the company, the dual-clutch gearbox will have a place in the future.

Therefore, there are more and more dual-clutch gearboxes for domestic cars.