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What are the different types of automatic car transmissions, and what are their differences?

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Car transmissions are mainly divided into: manual transmission and automatic transmission. Among them, automatic transmissions are further divided into ordinary automatic transmissions AT, AMT transmissions, CVT stepless transmissions / CVT transmissions with simulated gears, DSG dual-clutch transmissions, electronic stepless transmissions (E-CVT), and Honda's 8-speed DCT: Manual transmissions, also known as manual gears, require the use of a gear shift lever to change the meshing position of the gears inside the transmission, changing the gear ratio to achieve the purpose of changing speeds. The gear shift lever can only be moved when the clutch is fully depressed. Manual transmissions are the most traditional and oldest type of transmission. If driving
  Car transmissions are mainly divided into: manual transmission and automatic transmission. Among them, automatic transmissions are further divided into ordinary automatic transmission AT, AMT transmission, CVT stepless transmission/CVT transmission with simulated gears, DSG dual-clutch transmission, electronic continuously variable transmission (E-CVT), and Honda 8-speed DCT:
  Manual transmission, also known as manual gear, means that the gear meshing position in the gearbox can only be changed by manually moving the gear lever to change the gear ratio and achieve the purpose of changing speed. The gear lever can only be moved when the clutch is fully depressed. Manual transmission is the most traditional and oldest type of transmission. If the driver's skills are good, cars equipped with manual transmission are faster and more fuel-efficient during acceleration and overtaking than automatic transmission cars. Those who have passed the C1 driving test should be very familiar with it.
  Ordinary automatic transmission is the common type of transmission currently used in automatic cars. Its abbreviation AT (Auto Transmission) has almost become synonymous with automatic transmission. Ordinary automatic transmission consists of a hydraulic torque converter, planetary gears, and a hydraulic control system. It achieves speed and torque change through hydraulic transmission and gear combination. Among them, the hydraulic torque converter is the most important part of AT. It consists of components such as a pump wheel, a turbine, and a guide wheel, and it combines the functions of torque transmission and clutch. Manual transmission mainly changes gears by adjusting different gear combinations, while automatic transmission achieves speed change through hydraulic transmission and gear combinations. Generally, the gears of an automatic transmission are divided into P, R, N, D, 2, 1, or L, etc.
  AMT transmission (also known as automated manual transmission) is a mechanism that equips a conventional manual transmission and clutch with an electronically controlled hydraulic control system to achieve automatic gear shifting. In fact, it is based on the original manual transmission, which is a gear-type mechanical transmission (MT), and adds a microcomputer-controlled automatic control system to change the original manual operation system.
  Cars equipped with AMT no longer require a clutch pedal. Drivers only need to simply step on the accelerator pedal to easily start and drive the car. Among the three types of new automatic transmissions, AMT has relatively low technical difficulty, but there are problems affecting driving comfort, such as power interruption during shifting. In China, AMT is currently only used in some A0-level models. Due to the limited range of models and the relatively low-end vehicles, AMT lacks a platform for promotion, and its development prospects are the least optimistic among the three types of new automatic transmissions.
  CVT, Continuous Variable Transmission, mechanical continuously variable transmission. CVT uses a transmission belt and a variable-width ratchet to transmit power. That is, when the ratchet changes the width of the elbow, it correspondingly changes the contact radius of the drive wheel and the driven wheel on the transmission belt to change the speed. The transmission belt generally uses rubber belts, metal belts, and metal chains, etc. The CVT stepless transmission uses a transmission belt and main and driven wheels with variable working diameters to cooperate in transmitting power. It can achieve the best match between the transmission system and the engine operating conditions. The CVT mechanical continuously variable transmission is a type of automatic transmission mainly promoted by Japanese automakers, but the disadvantages of CVT are also obvious, that is, the transmission belt is easily damaged and cannot withstand large loads.
  DSG dual-clutch transmission. Volkswagen's DSG dual-clutch transmission is a new type of transmission with a subversive design. It not only inherits the high transmission efficiency of manual transmissions but also shifts gears faster than manual transmissions. The biggest difference between the DSG dual-clutch transmission and traditional dual-clutch transmissions is that it has a dual-clutch device composed of two sets of clutch plates and a dual transmission shaft mechanism composed of a solid shaft and its outer sleeve. It is controlled by a Mechatronic electronic control and hydraulic device that simultaneously controls the actions of the two sets of clutches and gear sets. Currently, there are not many models equipped with dual-clutch transmissions. Models such as the Volkswagen Magotan, Golf GTI, and the new Passat, all belonging to the Volkswagen Group, are equipped with dual-clutch transmissions.
  Electronic continuously variable transmission (E-CVT): This is currently the core technology of Toyota's hybrid technology (THS) and General Motors' hybrid technology (VoltecII). Toyota's THS was the first to be developed (1997) and is the most famous. Although the name contains "CVT", it is actually completely different from the commonly mentioned CVT (mechanical continuously variable transmission). Because it is the core part of the hybrid system, a brief introduction to the entire hybrid system is included. Taking Toyota THS as an example, its structure uses a planetary gear set to connect the two motors and the engine crankshaft. The large motor is directly connected to the wheels, while the engine speed is adjusted by the forward or reverse rotation of the other motor, without the need for a clutch or fluid transmission to interrupt the connection between the engine crankshaft and the gear set. The principle is to adjust the motor speed to keep the engine operating in a relatively high thermal efficiency condition (it can also make the engine become an oil-cut reverse drag state or directly shut down and stop); on the other hand, it can achieve energy recovery through the motor (with a battery pack acting as a power reservoir) to achieve low energy consumption of the entire vehicle. [General Motors' VoltecII is a bit more complex, using a dual-planetary gear set (bypassing Toyota's patent restrictions) and adding a clutch (for extreme fuel efficiency in individual operating conditions), but the principle is the same as THS.] Advantages: The transmission efficiency of the entire system is high, and the energy utilization rate is also high (very fuel-efficient). Because the engine operation is not directly connected to the wheels, the responsiveness and smoothness of the entire system are extremely high. Disadvantages: From the principle and structure, if the motor fails, the entire power system will be paralyzed, which is not suitable for harsh environments with very high reliability requirements. (However, Toyota has made the reliability of THS very good. Since its birth in 1997, there has been no news of any large-scale problem outbreaks. General Motors' VoltecII has just been launched, and it is too early to say.)
  Honda DCT: Honda adds a torque converter between the engine and the DCT transmission. The power first passes through the torque converter and then enters the dual clutch. Advantages: Faster shifting and relatively smoother driving experience at any time (compared with ordinary DCT, the torque converter can absorb the speed difference and vibration), and avoids the problem of clutch overheating in some cases with dual clutch. Disadvantages: High cost (the expensive part of AT is the torque converter).

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