If you have been watching cars on the Internet for a long time, you must often introduce such gearboxes as Aixin 6at and 7-speed wet dual clutch in the evaluation. However, the comfort and smoothness of different gearboxes are different when driving. What are the major differences and characteristics between them?
At present, the automobile market is divided into several types of transmission types with different structures, including manual transmission, at automatic transmission, M/at manual automatic transmission, double clutch transmission, CVT continuously variable transmission, E-CVT stepless transmission, electric vehicle fixed gear ratio single speed transmission, etc. I will explain each type in detail and combine with the gearbox I have tried Some feelings, try to speak simple and easy to understand.
Commonly known as mechanical transmission, depending on manual fluctuation gear lever to switch the gear meshing in the transmission, so as to change the transmission ratio to change the speed.
It can control the change of gear ratio freely, which is the favorite of old drivers. Through the control, it can achieve low shift gear, neutral gear sliding, etc. to reduce fuel consumption. If the drive is good, the ride comfort is comparable to that of automatic transmission. In the passenger car market, our common manual transmission types include 5-speed manual transmission and 6-speed manual transmission.
At automatic transmission
The internal part of automatic transmission is composed of hydraulic torque converter, planetary gear and hydraulic operating rod. The working principle of automatic transmission is relatively simple.
At present, at transmissions are the most diverse, ranging from 4at-10at. However, different gears have different characteristics. For vehicles that often run on bad roads or often deal with harsh environment, 4AT and 5AT transmissions are usually used, such as Pajero and palado. Although the ride comfort is poor, it is simple in structure, easy to repair, easy to shift and single gear The torque of bit is larger.
6at is the most common in the low-end models, because it is durable, stable and relatively smooth, such as Chang'an, Ford, GAC motor, red flag and other models are equipped with a large number of models. Among them, Aisin's 6at is more outstanding and has better ride comfort.
7at gearboxes are rare, and the compactness effect of the structure is not as good as that of 6at. It is difficult to achieve optimal mechanical structure for odd gears, and the cost and technical requirements are higher. Therefore, the popularity rate is not high. It is only used on a small number of medium and high-end models, such as Infiniti models, Nissan Tuda, etc.
8at gearbox is more common in luxury cars at present, among which ZF 8at is particularly famous, because the research of ZF shows that the transmission efficiency of 8at is improved by 15% compared with that of 6at, and the ride comfort is good, while 10At can only be increased by about 1%. However, its structure is more complex and the cost is high, so 8at is the most balanced transmission at present. Equipped with 8at, there are almost all BMW series, Audi high-end models, some high-performance cars, and even Rolls Royce Bentley super luxury models.
There is no doubt about the ride comfort of 9at transmission. Mercedes Benz and GM are the most well-known ones. They are all developed by themselves. The feature of GM is to increase the gear on the original 6at, but the size is almost the same, which can be put into the existing models. While the 9at of Mercedes Benz is characterized by vertical position, although its volume is a little larger, the performance in other aspects is quite excellent.
10At transmission is currently used in passenger cars with the most gears. It can obtain better ride comfort and economy. At present, the gearbox jointly developed by Honda, Ford and GM is applied, while the overseas version of ten generation Accord, Ford Mustang and F-150 are applied. According to the response, the effect is better.
Double clutch transmission
As the name implies, the double clutch gearbox works through two sets of clutches. After one clutch is linked with a gear, the other set is ready for the next gear. For example, clutch 1 is responsible for 135 gear, and clutch 2 is responsible for 246 gear. The shifting clearance is small and the smoothness is improved.
At present, 6-8-speed double clutch transmission is more common, and the performance of each gearbox is relatively unstable, and at the same time, it takes into account the advantages and disadvantages of the super automatic transmission.
At present, most of the 6-speed gearboxes are medium and low-end independent brands and joint venture models. BYD, Ford, Chery and other models are equipped with a large number of them. However, the effect is not so good. The gearbox of Ford and Chery, which have been tried in the early stage, have serious gear bumps at low speed, and still need to be optimized.
The 7-speed dual clutch has a wide range of applications. Compared with at transmission, it increases a lot of economy. Therefore, medium and low-end models will be equipped with them, such as great wall and Geely, but the performance is regular. Among the joint venture brands, VW's DSG is the most famous. Although it was criticized in the past, there were often times when the shifting logic was confused and there was a gear collision problem, but now it has been optimized very well. In addition, because of its fast shifting speed and no torque converter, it is also used in many performance vehicles and overtaking vehicles to help improve more performance. Of course, the best 7-speed dual clutch transmission still belongs to the PDK.
When it comes to the 8-speed dual clutch, at present, the most outstanding one is still the PDK transmission from Porsche. It is applied to Panamera and the 2019 911. It takes into account two major features at the same time, which is fast, stable and economical.
CVT continuously variable transmission
CVT transmission commonly known as stepless transmission, the structure includes driving wheel and driven wheel, transmission steel belt. Hydraulic torque converter, sensor, etc. In short, it depends on the hydraulic torque converter to change the hydraulic pressure and change the main part of the cone wheel