Finally got it!

<div class='quotetop'>QUOTE(kaze72 @ Sep 5 2007, 08:47 AM) [snapback]507198[/snapback]</div>

I'm sure this question has been answered before here, but here's my try anyhow. Yes, there is a considerable loss of energy when converting to and from electricity. Still, you gain, because:

1. You can get away with using a smaller, more efficient gas engine, tuned for less torque and for operating within a smaller range of rpm, since the electric motor can supply a boost when needed.
2. The gas engine doesn't idle. Idling is very inefficient, since gas engines don't perform very well at low power. It's more efficient to accept the conversion losses and store electricity in the battery, to use when you'd idle.
3. Regenerative braking: 'free' electricity. That is, a regular car would just throw that energy away. Not braking is of course even more efficient.

 

Congrats! Welcome to the club!

And yes, there is a loss of efficiency in converting to battery power. That's why it's best to avoid using the battery and gas all together when possible. P&G

 

<div class='quotetop'>QUOTE(kaze72 @ Sep 5 2007, 02:47 AM) [snapback]507198[/snapback]</div>

Only part of the power goes through the gas-electric-gas transition, and all of the power avoids a conventional transmission. The HSD trades some power losses in the conversion process for the following advantages:

1) Perfect power curve match from the engine to the road.

2) The ability to use a small, high efficiency but low torque Atkinson cycle engine.

3) Regenerative braking.

4) Engine shut-off when not needed.

Tom