First of all, the significance of hybrid electric vehicle is to assist the engine to transition to the optimal speed range when the engine starts or has a heavy load. That is to say, in the initial stage when the engine consumes a lot of fuel, a strong and low-torque motor comes in handy at this time, so as to achieve the purpose of quick start and fuel saving. However, the traditional hybrid mechanism, whether it is parallel or series hybrid, will have some setbacks when the motor or engine gear is engaged and the vehicle switches power modes, and Toyota has solved this problem with planetary gear sets for the first time.
Let's take a look at the structure of planetary gears, which are mainly composed of sun gear (sun gear), planetary gear, planet carrier and peripheral gear ring. These three layers of gears are meshed with each other and cannot rotate independently under normal circumstances. In Toyota's hybrid system, the outermost ring gear will determine the power output.
In the structure of three groups of gears, the rotation speed of the other two groups of gears will determine the rotation speed of the third group of gears, that is to say, the rotation speed of the planetary disc and the sun gear can determine the power output of the outer ring gear. That is to say, the engine can always keep the economic speed range, and the speed of power output can be controlled by changing the speed of the sun gear motor, which is why the E-CVT gearbox does not use clutches.
Theoretically, the transmission efficiency of the E-CVT gearbox without heavy torque converter and friction-driven clutch can reach 100%, but due to the efficiency loss caused by mechanical friction, according to Toyota, the transmission efficiency of this E-CVT is only 97%, but compared with the traditional gearbox, the efficiency of the E-CVT is already quite excellent.
In addition, the upgraded THS 2.0 does not adopt a brand-new naming method, but directly adds a 2.0 to the first generation THS, indicating that only some minor changes and optimizations have been made. Toyota official said that the PCU weight of the new THS 2.0 was reduced by 20%, and the motors were arranged on different shafts. To put it bluntly, it is the second generation gearbox assembly, which is smaller, lighter and more fuel efficient. This is also the original intention of Toyota to put forward the new global architecture (TNGA) hive concept.
It can be seen that Toyota attaches no less importance to hybrid and energy efficiency than any other brand. As early as the last century, Toyota was far-sighted and applied for a patent for its hybrid technology, which is why "there are only two kinds of hybrids in the world". Hybrid is also the core of Toyota's new TNGA hive concept. In the future, Toyota's A0 to D-class cars will be built under this framework, further deepening the core idea of TNGA honeycomb concept.