Although the designers of the Toyota Prius basically only use components that have been around for a long time, their combination represents something unprecedented. Thus the vehicle may well bear its name, which means as much as taking over a technical lead as the 'first'. Just look at the clutch bell at the top, which doesn't have a clutch at all.

There is also no torque converter behind it, as one might expect, but the smaller of the two electric motors with connection for liquid cooling. The larger one follows parallel to the axis further back, but is not directly connected. In between, marked with a dot, a planetary gear with chain connection to the axle drive. These are all just ingredients for a positive connection at all times, very good for avoiding losses.

Allegedly, Kiichiro Toyoda, the founder of the vehicle section of Toyota, had already exposed a high price for the search for a battery in 1928. The company was still at the very beginning and would just as well have been able to the introduction of electromobility. Perhaps the company would have been spared a few of the problems that arose.

The three videos above and below only show the principle. In reverse and slow forward driving, the right, larger motor drives the front wheels. The smaller left engine e.g. serves for (unnoticeable) start of combustion engine from about 30 km/h. It changes over to become a generator that supplies parts of the engine power of the combustion engine to the battery.

Forward gear - electrically . . .

Since the videos always have only one motor, it can be shown here very nicely, how the transmission ratio between motor and axle drive is changed. It is the torque, which this generator is required from the combustion engine via the power switch on the planetary drive, which controls the transmission. Much of this reduces the output of speed to the rear, little increases it.

Forward by combustion engine . .