Automatic transmission (AMT) can determine the best gear according to parameters such as vehicle speed, throttle and driver's instruction, and control manual operation processes such as clutch disengagement and engagement, gear shifting of gear shifting handle, and synchronous adjustment of engine throttle opening, so as to finally realize the automation of gear shifting process.
Compared with CVT, AMT has the following advantages: low cost and favorable production; More convenient maintenance and lower cost; Products can be well matched. The most obvious disadvantage of AMT is its strong sense of frustration.
CVT (continuously variable transmission) is the full name of continuously variable transmission technology. CVT can be said to be the most ideal automobile transmission, because from the initial rubber belt CVT, to the stepped gear transmission, to the modern steel belt CVT, the century-long revolution shows that only CVT is the ultimate goal of automobile transmission.
Advantages of CVT: good fuel economy, good power, good comfort, good maneuverability and less harmful gas emission.
Extended data:
The structure of CVT is mainly composed of two groups of pulleys (driving pulley and driven pulley) and transmission belt (steel belt) oil pump, hydraulic torque converter, actuator (valve body and oil circuit), sensor and computer.
The function of hydraulic torque converter is to transfer the torque of engine to CVT, so that the car can start forward and backward smoothly. Hydraulic torque converter can amplify the torque of the engine and make it start faster. When the vehicle speed reaches the set speed, the pump wheel (wheel connected to the engine) and turbine wheel (wheel connected to CVT) of the hydraulic torque converter are locked, and the transmission efficiency at this time reaches 100%.
CVT has two groups of pulleys (driving pulley and driven pulley), and each group of pulleys is divided into two halves. One side of the pulley is fixed, and the other side of the pulley can slide on the shaft. The inner sides of the two pulleys are conical surfaces with inclined angles, and the two sides are opposite to each other to form a V-shaped groove, which is in contact with one side (meshing point) of the drive belt.
The conveyor belt consists of two annular steel belts and a pusher, each group has two annular steel belts, and each belt is made of 12 layers (sheets) of high-strength thin steel plates. The steel belt adopts T702 high-strength steel (the tensile strength of each piece reaches 2000Mpa), and the pusher consists of more than 400 high-strength pressure steel plates. The function of the push rod is to transmit torque through extrusion thrust. ?
The imported third-generation CVT adopts more advanced ASC control unit on the basis of the second-generation CVT. The number of variable speed conversion modes has increased from 20 to more than 700. The computer can calculate and judge the driver's intention at any time through the information provided by sensors such as accelerator pedal, engine speed, vehicle speed and shift lever position, and then send control instructions to the execution system to provide actions that meet the driver's wishes at any time, which can quickly and accurately execute various instructions issued by ASC control unit.
References:
AMT gearbox-Baidu Encyclopedia