Disadvantages and advantages of automatic transmission Introduction of several common automatic gearboxes

　　　Gearbox is an important part of automobile power. Nowadays, various automatic gearboxes can be seen everywhere in the market. Different automatic gearboxes have different performance and quality. What are the disadvantages and advantages of these automatic gearboxes? Here are some common automatic gearboxes for everyone.

　　Automatic gearbox type

　　AT present, there are three common automatic gearboxes: AT (hydraulic automatic gearbox), CVT (continuously variable automatic gearbox) and D (dual clutch gearbox).

　　First, AT— automatic transmission

　　AT is to use a hydraulic torque converter instead of the dry clutch in the traditional manual gearbox to transmit the power of the engine to the planetary gear mechanism, and realize automatic gear shifting through the electronic control system. AT the same time, the AT gearbox is not as many gears as possible. Because the structure of its planetary gear mechanism is very complicated, adding one more gear will greatly improve its structural complexity, gearbox volume and R&D and manufacturing cost. Of course, there is another problem, that is, the more complicated the structure, the lower the mechanical reliability.

　　Advantages of AT automatic gearbox

　　1. AT gearbox is the most widely used gearbox in the market today, and its mature mechanical structure has been developed and carried forward by many manufacturers.

　　2. The traditional hydraulic automatic transmission adopts hydraulic torque converter (or hydraulic coupler, multi-disc clutch, etc.), which can cushion the power impact of the engine and match the mechanical combination of planetary gears with stable performance. The torque it can withstand is also very high.

　　Disadvantages of AT automatic gearbox

　　1. The AT gearbox needs more mechanical parts, which makes the overall weight larger and the manufacturing cost higher than other gearboxes.

　　2. Because the engine power needs to be transmitted to the gear set through the hydraulic torque converter (or multiple clutches, etc.), part of the engine power will be consumed in vain, so compared with the manual gearbox (including CVT gearbox), the AT gearbox will consume more oil.

　　The fixed gear set used in 3AT gearbox makes the vehicle stumble and make noise when shifting gears. Although the shift impact is greatly optimized with the development of technology, the AT gearbox is still not very smooth in theory.

　　Second, DCT— Double clutch automatic gearbox

　　DCT is actually a general term, such as G and powersht, which are all powershift. They are similar. powershift has fast gear shifting, high fuel economy and can bear large torque. Now it has been widely used in the automobile field. Its transmission mechanism is the same as that of the traditional manual gearbox, but because the two groups of clutches operate independently and alternately, it can almost achieve CVT-like power output. This kind of gearbox has two branches: dry dual-clutch gearbox and wet dual-clutch gearbox. The difference is that dry DCT is. The two sets of clutch plates of wet DCT are in a sealed oil tank, which absorbs heat through the transmission oil soaked with clutch plates.

　　Advantages of DCT automatic gearbox

　　1. The transmission efficiency is high, the power loss is small, and the fuel economy is relatively best.

　　2. The shift response is fast, and the shift smoothness is only slightly inferior to CVT.

　　3. Because its transmission structure is the same as that of manual gearbox, it has the highest bearing capacity.