What are the types of automatic transmissions?
3 Answers
Currently, the most common automatic transmissions on the market mainly fall into the following four categories: 1. AT transmission, officially named torque converter automatic transmission, which is the most widely used type. It has evolved from early 4AT transmissions to current 9AT transmissions in some vehicles. The advantages of AT transmissions are obvious, offering more direct power delivery, but they also have notable drawbacks such as noticeable jerking during acceleration and relatively higher fuel consumption. 2. CVT transmission, officially named continuously variable transmission, is primarily represented by Japanese car manufacturers, with models from Honda and Nissan mostly using CVT transmissions. The characteristics of CVT transmissions are distinct; since the gear ratio is not fixed but a continuous range of values, it provides excellent smoothness and outstanding fuel economy. However, the downside is relatively obvious, as it lacks sudden bursts of power output, making it relatively gentle. 3. AMT transmission, short for automated manual transmission, is a compromise between MT and AT transmissions. Its advantage lies in lower production costs and more convenient operation compared to manual transmissions. However, the drawbacks of AMT transmissions are more pronounced; poor operation can easily lead to strong jerking, significantly affecting comfort. Moreover, few models on the market are currently equipped with AMT transmissions. 4. Dual-clutch transmission, abbreviated as DCT, as the name suggests, uses two sets of clutches that alternate to achieve seamless gear shifts. It is further divided into dry and wet dual-clutch types. DCT transmissions offer fast shifting speeds, minimal power loss during gear changes, and good fuel economy. However, the disadvantages of dual-clutch transmissions are more evident, with stability in quality being a major drawback.
As a seasoned driver who frequently drives American cars, I've mainly experienced three types of automatic transmissions: the old-school AT transmission shifts via a hydraulic torque converter, smooth but a bit fuel-thirsty; the CVT continuously variable transmission operates like a chain-and-pulley system, delivering silky acceleration like in the Honda Civic; the DCT dual-clutch transmission shifts lightning-fast, with the Golf GTI's version even producing popping exhaust burbles on downshifts. Nowadays, hybrids have their dedicated E-CVT, which Toyota hybrids rely on to cleverly distribute power. If you've tinkered with older cars, you might've encountered the AMT semi-automatic - it frees your left foot but delivers jerky shifts that'll rock you back and forth.
Last time when I was reading an automotive science picture book with my daughter, I learned that the automatic transmission family is so diverse. The gear-set type AT is the most common, like in our old Camry; CVT with steel belts works like bicycle chain shifting, making the Sylphy drive exceptionally smooth. Sports cars prefer dual-clutch transmissions, with PDK gearshifts completing in the blink of an eye. New energy vehicles even hide electronic transmissions, where Tesla's single-speed gearbox is as quiet as a well-behaved baby. But the most interesting is the AMT in driving school cars, which requires reaction time for shifts, much like a semi-automatic rifle.
