Jason

The Prius has a planetary gear set like an old 3 speed bike but way newer/better/cooler. Instead of 3 fixed ratios like the ole 3 speed a Prius uses the planetary gear as a "split power device" to blend the power from both the engine (ICE) and one of the motors. How fast and which direction the motor turns determine the final gear ratio. With the electric motor spinning one way the system is geared down like shifting into a low gear. At some point the motor stops and turns the other way, which makes the ratio taller like shifting a car into overdrive. I'll edit in a link in case you care.


Too late to stop me:

http://home.earthlink.net/~graham1/M...Understanding/

http://home.earthlink.net/~graham1/M...PowerTrain.htm

http://home.earthlink.net/~graham1/M...plitDevice.htm

The Toyota split power device is the heart of the whole system and it is brilliant!