"Doctor Evil" wrote in message
eenews.net...

"Andy Luckman (AJL Electronics)" wrote in message
. ..
In article , Dave Plowman (News)
wrote:

The latest Prius is an amazing success. It doesn't have a gearbox,
just
one plaetary gear assembly.

Whereas a gearbox is what?

Shifting ratios between cogs. The Prius doesn't do this or have a CVT
which
has pullies and a belt. Just a simple assemmbly.

It has no mechanical transmission. No mechanism to shift gears or wind
pullies in and out. It is very simple. You need to look more and
understand
how a planetary system works. There is no ratio selection. It is simpler
than a normal car. No complex power sapping transmission, juts a
planetary
gear assembly, which
just turns, as do bearings. The "complexity" is people not understanding
it.


OK, Thanks for the suggestion, I know it all now. Interesting. G

The Prius planetary gear works like a flattened out differential where the
two 'halfshafts' are driven by the petrol engine and the electric motor
driving the wheels, and the 'driveshaft' takes power to the generator.

So by varying the relative speeds of the petrol engine (by throttle) and
electric motor (by speed controller) you can get almost any ratio you like
from reverse to full ahead, and any power split between wheels and
generator... Nice.

Try here for a simulation
http://homepage.mac.com/inachan/prius/planet_e.html or here for a nice
explanation in diff terms
http://home.earthlink.net/~graham1/MyToyotaPrius/SideBars/PsdLikeDiff.htm