In article ,
wrote:
Only while there's some battery charge. Once that is exhausted, the
petrol engine is effectively driving the wheels direct, but via a
generator and electric motor or some form of split drive. Hence the
poor consumption under those conditions.

So am I right in thinking that (roughly speaking) for continuous running
a conventional system is more efficient, whereas doing a lot of
shuffling along in heavy traffic a hybrid can be better?
Yes - with lots of stop start stuff obviously an electric motor which
doesn't idle will be more efficient *at that time*. Of course if you want
heating or air-con, this will make a big difference.

Has anyone done the figures (for current production technology
conventional and hybrids) to work out which would be better averaged out
over national traffic patterns? In other words, if you were to replace
the entire national car fleet overnight with equivalent hybrids would
net fuel consumption increase or decrease?

Autocar have a standard test route over which they take all the cars they
test. It's about 30 miles long and involves a mixture of suburban high
streets and 50 mph highways. The Prius managed 42 mpg over this journey.
Almost exactly the same as a BMW 330D - a very fast diesel. Any other
small diesel - Focus etc - is nearer 60 mpg over the same route.

--
*Eagles may soar, but weasels don't get sucked into jet engines *

Dave Plowman London SW
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