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