There was much discussion in this thread about a diesel hybrid
It turns out that GM of all people is way ahead in devloping hybrid
diesel - in buses. the following links tell the story - diesel, hybrid,
regenerative braking - the lot! 60% gain in economy.
I owe it to an Australian electronics magazine - Silicon Chip - which
is running an article in its June issue on this GM - Allison project
which is not pie in the sky - the vehicles are operating in various
parts of the US.
Still dont see it, my friend has a commonrail TD and gets 45 doing city
driving, which is still above a hybrid?
Would be harder than with a petrol - re-starting a diesel requires far more
cranking torque, so you'd need more powerful motors and its likely to cause
a jerk, unlike a petrol car that can smoothly be 'bumped' as its low
We get mid/upper 40s in our hybrid around this hilly mountain town even with
short trips and cold weather. In Phoenix it is consistently over 50 mpg in
town, running A/C in a car that carries 5 adults easily and has what is
effectively a perfectly smooth automatic transmission. Sitting at lights it
is dead quiet most of the time and on the road it's still on the quiet side
of average. In all states in the US it has the SULEV emissions rating. The
merging capability is better than any of our other cars, including our 1985
turbo Volvo (gotta hate that turbo lag!) Ours is the older, less efficient
version - and represents a technology in its infancy.
I give diesel its due: it has undeniable advantages as an auto fuel.
I would speculate that one problem with a diesel hybrid would be the
extra power needed to crank the engine, remembering that this will
happen quite frequently in a hybrid. This may mean more batteries
(and hence weight) and a heavier engine anyway, meaning that the
engine will need to run more frequently than it would in a petrol
The hybrids that I have seen have clearly been designed to minimise
weight, even perhaps compromising braking and cornering performance by
fitting narrower tyres. With present technology, it is even possible
that the extra weight required by a diesel engine would cancel out the
gain in fuel economy compared to a petrol engine.
The one thing that would really make hybrids irresistable would be a
means of charging the batteries from the mains. That way, even less
fuel would be burned (at least by the car). But I doubt the oil
companies would allow that to happen.
Created on the Iyonix PC - the world's fastest RISC OS computer.
Yep. On rare occasions mine shudders slightly when shutting down but
otherwise it's not noticeable. A common hybrid experience is sitting at a
light listening to the folks around you wasting fuel for no good reason. I
corrected the subject line.
Actually, my Peugeot 406 HDI diesel (the common rail engine) averages 46mpg
. This means that, to average 46, it must at times exceed 50 to counteract
higher consumption in traffic. Bear in mind though that these averages are
using the Imperial gallon, not the smaller US one. Factoring the US
gallon into my spreadsheet shows an average of 35mpg(US). I assume that
the figures quoted for the hybrid are US, not Imperial?
(If you can't laugh at life, it ain't worth living!)
Yes, the figures for the hybrid are US gallons. In the past year, my
lowest mileage for a tank of gas has been 48 MPG; the highest has been
52 MPG. My highest ever was 53.4 MPG. And except for the first two
tanks of gas, I have never had less than 46 MPG on a tank.
Stop Mad Cowboy Disease: Impeach the son of a Bush.
interesting, anyone know what causes better mileage in winter?
higher density of fuel due to cold? not running a/c? lower motor
winding resistance due to cold?
is this a common phenomenon?
is it true for non-hybrid cars, or only hybrid cars?
I'm not sure that hybrid vehicles get better fuel economy in the winter than
in the summer. For conventional internal combustion engines, the air is
denser in cold weather so theoretically, the air-fuel mixture burns more
completely. The engine takes longer to warm up in the winter so the
air-fuel mixture is enriched a little longer so in the real world, most
people tend to get better fuel economy in warmer weather.
Well, I can tell you this with a lot of certainty, large piston
aircraft engines produce much more power at low temperatures than
at high temperatures and the reason is that the air is much
denser when cold than warm.
These engines have MAP gauges (Manifold Air Pressure...they're
supercharged) and in summer they'll reach their maximum MAP
before they reach their maximum 'torque', while in winter they
reach max torque well before max MAP...quite a large
difference...(this is at 'take-off' power)
The temp of the fuel apparently makes not much difference because
we only used one weight for fuel winter and summer, it was 7.2
pounds per Imperial gallon (very high octane fuel). The aircraft
held 6,640 gallons and if temp had mattered much then we'd have
needed to take it into consideration in those large numbers...
It is not true, the real thing is that the Prius has lower mpg's at winter,
it is because it's main target is to be a close to zero emission vehicle, so
at colder weather the catalyzer needs more gases going through it to keep at
good work temperature to avoid contamination.
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