Hybrid Synergy Drive

Power Split Device:
How Does The Toyota Prius Work? The Prius employs a power split device to blend the power of the gas engine, the electric motor, or both, depending on the driving situation. Toyota calls it Hybrid Synergy Drive (HSD). Switching between the differing combinations of power sources is pretty seamless and if it weren’t for the energy consumption screen located in the Prius’ center console, the driver would have little indication the complexity of it all.

Low Loads Under low loads, the Prius can be powered solely by the electric motor with energy coming from the battery pack. This provides for silent driving for short periods of time. This is in contrast to other “mild hybrids” such as Honda Civic, Accord and Insight. The Hondas use the electric motor simply as a power assist to the gas engine, and can never run on the electric motor alone.

Heavy Acceleration

Under heavy acceleration the Prius integrates both the electric motor and the gas engine, again with additional energy coming from the battery.

Highway Speed

At highway speeds the Prius uses the gas engine to move it along generating additional electricity to the battery via the generator if needed.

Coming To A Stop

When coming to a stop, the Prius turns off the gas engine which improves the gas mileage and keeps the air cleaner.

No more wasted gas waiting for the light to change. As soon as you are ready to move forward the Prius comes to life, providing the right combination of propulsion. Does It Need To Be Plugged In? No, the system constantly monitors the energy state of the battery and uses the gas engine, coupled with the generator to keep the battery charged. The Prius also recaptures the otherwise wasted kinetic energy when braking or decelerating to charge the battery.