In fact, they are all automatic transmissions, just one of the implementation modes, that is, you can drive by shifting to D gear and pressing the gas. It’s just that the dual-clutch gearbox is more like a manual gearbox in terms of mechanical structure. It uses various electronic and mechanical devices to control two sets of clutches. One set controls the odd-numbered gears (1/3/5 gears), and the other set controls Even-numbered gears (2/4/6 gears). The advantage of this is: when the gear is in 1st gear, 2nd gear is also ready, but the clutch plate is not connected. When you need to change gears, quickly disengage the 1st gear clutch and close the 2nd gear clutch. Shift into gear, and at this time, 3rd gear is also ready, and so on. This way, you can shift gears faster, obtain smoother shifts, lower power loss, and reduce fuel consumption. Of course, the above operations are all controlled by the trip computer without human intervention, so the driving mode is still automatic.
The current automatic transmission modes are mainly the following:
1. Planetary gear type (the most common automatic transmission)
2. Dual clutch type (Represented by Volkswagen DSG and Ford Power-Shift, many supercars also use this method, which can provide faster shifting speeds)
3. CVT continuously variable transmission (similar to a pulley structure, made of steel The advantage of belt drive is that the acceleration is very smooth, without interruption, the engine is always in a good working condition, and the fuel consumption is better reduced. The disadvantage is that it cannot transmit large torque, and it cannot be used on large-displacement cars and diesel-powered cars. Represented by small-displacement vehicles (2.5L and below) and Toyota hybrid vehicles (Prius, Lexus CT200h, etc.) and Subaru civilian-grade small-displacement vehicles (2.5L and below))
4. Parallel axes (Honda's patent, the structure is more like a manual transmission, the gear set is distributed on 2 to 3 parallel axes, the structure is simpler, light weight, and low fuel consumption, but the disadvantage is that it is difficult to make more gears, currently 5-speed Mainly, it is a bit outdated in the face of automatic transmissions that often have 6, 7 gears, or even 8 or 9 gears. Most of the vehicles currently sold by Honda adopt this form)
5 .Mechanical automatic transmission, referred to as AMT (complete manual transmission, plus an electric shift fork and electronic control unit, simulates an automatic transmission. The advantage is that the structure is simple and the cost is relatively low, but there are also many disadvantages , for example, the gear shift is not smooth, and the frustration is very obvious when changing gears. In addition, it is easy to slip back when starting on a slope. You need to use the handbrake to cooperate or step on the brake with your left foot, tap the accelerator with your right foot, and then release your left foot. , so it is rarely used in cars. Only a small number of low-end cars will use this gearbox, such as MG3, Chevrolet Sail, Chery or other low-end products of independent brands. Although this gearbox has many shortcomings, there is one. The biggest feature is that because it is based on a manual gearbox, it can be easily enlarged to transmit very large torque, so automatic transmission heavy trucks, buses, etc. are more suitable for using this kind of gearbox