Dave Plowman (News) wrote:
In article ,
Andy Champ wrote:
(however you are correct, a diesel-electric with a generator and battery
set does have the opportunity to take the engine efficiency up a bit.
Not least because it can be tuned to run at one speed only)

But what speed do you set that at? That's the exact problem with the
Pious. The engine is tuned to run best at a particular speed. Exceed the
power it produces at that and it becomes horribly inefficient. Drive
slowly and with economy in mind and it can produce quite good results. As,
of course, can most other cars of that size. Load it up and drive it a bit
harder - like keeping up with the traffic on a motorway hill - and it
becomes far less economical than a conventional car. As well as being a
pain in the arse to drive.

yerrs. Its a classic storage resolution to demand variation. The pious
is supposed to usee the battery to get up to speed and the engine at
peak eff to stay there on motorways. Sadly the engine is no better than
any other engine at that optimal speed and having to carry around all
the storage is juts extra weight.

Its precisely the same as having windmills on the grid..and using a gas
engine to balance them. Nearly all the gains are wiped out by the
needful fluctuations in the gas engine, and the net result is cumbersome
and expensive and ultimately not advantageous