Regenerative Braking

Reuse of kinetic energy by using the electric motors to regenerate electricity

HYBRID SYNERGY DRIVE can reuse kinetic energy by using its electric motors to regenerate electricity in what is called "regenerative braking".
Normally, electric motors are turned by passing an electric current through it. However, if some outside force is used to turn the electric motors, it functions as a generator and produces electricity. This makes it possible to employ the rotational force of the driving axle to turn the electric motors, thus regenerating electric energy for storage in the battery and simultaneously slowing the car with the regenerative resistance of the electric motors.
The system coordinates regenerative braking and the braking operation of the conventional hydraulic brakes so that kinetic energy, which is normally discarded as friction heat when braking, can be collected for later reuse in normal driving mode.
Typically, driving in city traffic entails a cycle of acceleration followed by deceleration. The energy recovery ratio under these driving conditions can therefore be quite high.
To take advantage of this situation, the system proactively uses regenerative braking when running the car in the low speed range. Taking Prius as an example, the system can save the energy equivalent of 1ℓ of gas/petrol while running in city traffic for 100 km.