[supergeek]

If I recall correctly, the prius ICE and EV systems are totally isolated and only connected by the road in between the front and rear tires. The ICE runs the front tires and the EV system is hooked up to the rear tires. You mostly charge the battery up by slowing the car down with the rear tires, so you'd need to modify the car with some belts or linkage between the front and rear drives.

[camhenlin]

In Toyota's hybrid synergy drive, the electric motor system is inputting to the same transmission as the ICE engine, and is an integral part of the casing. You can see a cutaway of it here to get an idea of what it looks like in practice: https://en.wikipedia.org/wiki/Hybrid_vehicle_drivetrain#/med... What you're describing is indeed how the E-Four system works for the rear wheels on the AWD versions of the Prius