送交者: skipper3 于 2005-10-13, 17:09:21:
回答: If two drives hybrid on a highway 由 HunHunSheng 于 2005-10-13, 16:32:18:
Your efficiency theory is flawed: it's more of efficiency of the power train than that of a motor.
For electrical driven vehicle, I heard a motor can actually drive a drive axle directly. This is possible because the output torque of an electrical motor is almost constant regardless how fast it turns, according to my reading.
For a gas motor things are very different. It needs to run within certain range of rotational velocity in order to get out most of its power and efficiency. So this makes thing complicated: you need a gear box between the motor and drive axle. Every one knows a gear box is not 100% energy efficient. The gear is lower the less efficiency. A typical car is in its 2nd gear at 20mph. At 55mph it should be in its top gear. That's the primary reason it consumes more gas running slow.
Now if a electrical driven car still uses a conventional transmission (gear box), I don't think it will actually improve fule efficiency significantly, provided everything being equal.