What is E-CVT? Structure and working principle of E-CVT

The electronic continuously variable transmission is officially defined as "power distributor" by Toyota. It is specially designed for hybrid electric vehicles, which is different from the traditional gearbox system because it does not include traditional gearbox parts such as clutch, torque converter or gear shaft. So some people question whether E-CVT can still be called transmission? However, the appearance of the hybrid version from Prius to Lexus CT200h to Camry proves that Toyota's hybrid system is becoming more and more mature. ECT is a key component of the whole system and plays a vital role. E-CVT structure From the traditional transmission point of view, the structure of E-CvT is very simple, and the reduction mechanism of planetary gear set is its key part, without chain and steel belt, so it is not easy to have the fault like double clutch. The working principle of electronic continuously variable transmission The mechanical movement principle of ECT is not complicated, and the movement of planetary gear set can be said to be very simple, but what is complicated is its electronic control unit, that is, the logical principle of electromechanical coordination. Before introducing the working principle, some terms are listed: PCU is an important part of hybrid electric vehicle, which includes a voltage converter and an inverter to adjust the output voltage of battery pack; The function of inverter is to convert DC into AC, and vice versa, because high-voltage AC motor has the advantages of small size, high efficiency and high power; MG 1 is the motor generator connected to sun gear1; MG2 is a motor generator 2, which is connected to the outer ring gear. The power flow direction of ECT in various driving modes is 1. Electric drive mode: only the power when the motor is running flows to the motor->; Motor shaft-intermediate shaft-main reducer-differential-driving gear-main reducer-differential-driving half shaft 2. Hybrid (extended range) driving mode: power flow when the engine and motor are started together 3. Engine drive mode: power flow is only driven by engine-flywheel-input shaft-overrunning clutch-clutch. Motor (running in reverse)-> Motor shaft-auxiliary shaft-main reducer-driving gear-differential-driving half shaft.