[quote=Double-Trinity]This is true as the electric motor (actually, two electric motors) in the Prius are required for the transmission to function. The Prius tranmission is essentially a single gear system. In high gear, it simply tranmsits the engine power mechanically. However, In order to get torque for "low gearing", it must convert some of the engine's mechanical power into electrical, with one motor acting as a generator powering the other. This must happen even if there is no flow of power into or out of the battery. This is also the reasno why the Toyota Hybrid System won't work for off-road driving, where slippy conditons can damage the motors, a true mechanical tranmission would be needed.QUOTE]

My understanding is that the Prius uses a CVT transmission.

You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.

Lifespeed

2003 Civic Hybrid 5 speed