John Rumm wrote:
Doctor Drivel wrote:

The ratio is continously variable


.....oh no! failure. The planetary cluster is referred to as a
power-splitter. A normal gearbox/CVT lowers and raises ratios. No
ratios are raised and lowered.

Nonsense. The wheel speed can vary independently of the engine or
motor speed. Therefore the ratio varies.

With you so far

Back to basics. If you apply the correct power/torque at the wheels
you don't need a gearbox. An electric car doesn't have a gearbox
because the electric motors can do this.

However this is not what happens in the prius...

Agreed.


The Prius splits the power from the two power sources, which are
approx 70

More correctly it combines power from two sources. No need to split
two independent things.

It *does* split the power from the two sources - between the wheels and the
generator. It takes in variable amounts from each source and sends it in
variable amounts to the wheels and generator. 0-100% on both sides.
Ingenious really.

hp each, and sends the combined power to the wheels.
No raising or lowering
of ratios,

The wheel speed is not fixed for a given engine speed. Therefore the
ratios change.

That is what it does. Simple.

Yup, simple CVT.

'Tis a CVT. 'simple' as in ingeniously designed and hence more efficient,
less complex, smaller rather than 'simple' as in run of the mill as fitted
to Festers, for instance.

Therefor it has CVT

Wrong as usual.

No CVT. Toyota say it has an electric CVT

Now lets just look at that sentence shall we... spot any
inconsistencies?
marketing purposes only, as they think a departure from a gearbox is
something the public are not tuned up to. In practice it doesn't
need one; just clever application of power/torque.

Through a planetary gear that matches the engine speed to wheel speed
by variation of the effective gear ratio. The differential speed of
the power sources dictates the ratio.

What these outfits are doing is building plug-in hybrid vehicles,
PHEVs. PHEVs still have petrol engines which turn electric motors to
charge the

Pretty much what they have done on trains for years then... (except
with batteries)


Yep. And it works well.

Of course I'm still waiting for one that runs a small diesel at continuous
optimum revs (or off) like trains do.. should improve economy etc. no end.

Still needs much better battery technology though. That's holding so many
things up :-(