On 29-Sep-17 3:19 PM, NY wrote:
"Tim Streater" wrote in message
.. .
In article , NY
wrote:

If the car has a range of only a mile or so on battery, how is a
hybrid any better than a petrol-mechanical car where the engine runs
all the time. I presume hybrids like the Toyota Yaris are
petrol-mechanical rather than petrol-generator-motor during the times
that the engine is running - ie that there is a mechanical
transmission (whether manual, torque converter or CVT).

I don't remember the proper term for the gear-box type but it can
accept two sources of input power (from the petrol engine and the
electric motor) and feed that to the wheels.

Oh, so the electric motor still goes through the variable-ratio gearbox
rather than being a single ratio from 0 to maximum road speed? Seems to
defeat one of the big advantages of an electric motor - that unlike an
IC engine it has torque at zero rpm and over the whole operating speed.

The Toyota device is called a "power split device".

Planet gearbox has 3 shafts.
1: IC engine.
2: Motor/gen 1.
3: Motor/gen 2 and output to diff.

The "gear" ratio is changed by the speed of Motor/gen 1.

http://prius.ecrostech.com/original/...plitDevice.htm

Lt. Col. L. F. R. Fell patented a 3 differential, 4 engine power
combiner used on Loco 10100.
http://www.paxmanhistory.org.uk/paxfell.htm