Petrol price to jump in the weeks ahead

I'm still not keen on nukes until we either get fusion or work out how
to safely get rid of fission waste. If we can do either then bring it
on. Otherwise we are just shifting the problems further down the line.

 

Diesels make ideal stationary engines and will run very effeciently
indeed at fixed speed settings.

I think you are discussing something other than a modern turbo-diesel.
Modern turbo-diesels have more Pwer and more torque than their
comparable petrol-engined cousins, whilst using less fuel. Last year I
traded my ford Courier ute for a diesel Ranger. OK the engine had 15%
more cubic capacity but it produces 28% more power and twice the
torque. Acceleration is also better.
An interesting comparison is the BMW 320i and 320d
The Petrol version has 115 Kw to the diesel's 130 and 200Nm to the
diesels 350. Engines are identical in size, the diesel model does
weigh 85 kg more but does 0-100 in 8.0 compared to 9.0 for the petrol
version. The diesel is also 8km faster in top speed. whilst the petrol
model is fairly frugal at 8.0 l/100kmthe diesel achieves 5.4. In city
traffic the petrol uses 11.3 to the diesel's 7.0. Country running sees
the diesel at 4.4l/100km. I've read road test reports that say you
won't achieve even 5.0 in highway running in the Prius.

Theo

 

I was speculating on a question about why diesels aren't used in
hybrid systems to date. This is a is very specific application where
the current petrol engines are highly modified . Diesels need to be
modified too, in diesel specific ways. As I have repeatedly said, they
can be, but there is no will to do so at present.
I agree with everything you say about automotive diesels and the
current state of development. However if you think the hybrid
requires an engine with stationary engine (or automotive)
characteristics then I humbly suggest that you are wrong. The
application is quite unique, and neither automotive nor stationary
engines are suited without a great deal of modification.
BTW, on highway running with the hired Prius about 3 years ago, over a
distance of several hundred ks, the average consumption was less than
4.5. The average around town was similar. And no one has ever accused
me of having a light foot. I've read similar reports (+5k/l) to you,
but I don't think they have a very close match with realty.
Of course Hybrid is not the ultimate answer, nor are little
breathlessly screaming diesels. Only a fool would think they are. They
are stop-gap measures until the ultimate answer (whatever that
is)comes along.

 

A small, deep facility in our very large outback would be perfectly
adequate.

 

Not stop start driving but the engine stop / start of hybrid operation
around town would not be the ideal diesel environment

 

We've got 2 Focus 2.0 litre petrol sedans at work. They average about 8
litres per 100kms, the Focus diesel averages 6 litres per 100kms.

When I had a Prius to drive it average worse than that.


G-S

 

So why not a turbo-diesel hybrid then?

Using a petrol motor seems a poor choice.


G-S

 

Yes but the Yaris has both worse performance than a Golf turbo diesel
and poorer fuel economy.

The Prius has similar performance to the Yaris (worse than the Golf) and
similar economy to the Golf (worse on the highway).

The only place where the Prius is best is INNER city running in stop
start peak hour traffic and I see more in the suburbs or out on the
highway than I do in peak hour traffic.


G-S

 

I think GWD and Bill_H have missed that JL is proposing that the diesel
ONLY charges the battery (continuously) so it doesn't have that
start/stop or throttle problems you've mentioned.

 

*ding* *ding*

We have a winner!


G-S

 

They do! Friend o' mine has an electric go kart with a 48 volt forklift
motor in...we don't know how fast it could go cos the chassis is a bit
agricultural and the brakes marginally existant

But it gets to 80 k's in a few seconds with the wheels spinning

And there's an electric drag racing series with bikes down to 7s quarters

http://www.nedra.com/record_holders.html

 

I got 6.5 litres per hundred kilometres in country running in a Prius
and I wasn't pushing it.


G-S

 

Yeah, you are probably right.
Kind of like what the Yanks are doing?
I think that system is inferior because of the double whammy in
efficiency - firstly via the charger-battery system, then via the
battery/drive system. Hybrids don't have anything like these losses,
the engine drives the main shaft directly just like an automatic, and
the motor/generator harvests wasted energy due to transmission
slippage for later re-use. Much more efficient on paper but a pity
about the weight penalty. The up-side is that there is plenty of room
for development.

 

That's different from my experience over a week of city and country
driving.
<shrug>
Maybe I had a Wednesday car.

 

Why would I misunderstand it. He was pretty damn specific about it.
Check through their podcasts. Problem is I can't specifically recall
which programme it was on. I think it may have been Life Matters, but
may have been the Science Show. An email to RN would probably point
you at the podcast.

 

Indeed, it's not like we're Singapore or Japan, there's no shortage of
marginal land we could utilise - the former nuclear test sites at
Maralinga spring to mind.

JL

 

I'm not at all familiar with diesel trains at all so I can't comment,
but I'd be surprised if they had large electrical storage on board.

I was suggesting the exact same config as a Prius but where you have a
very small diesel motor running as required to top up the batteries,
with regen braking back to batteries as well - a small HP / small cc
diesel set up for max efficiency could generate enough electricity
into storage over a longer period to be quite practical and very
economical. It's the reverse logic of a Prius in terms of use -
instead of switching off a petrol motor any time it's not being used
and use the petrol to provide extra HP, you'd run a small diesel near
continuously and allow the electric motor to do 100% of the driving of
the wheels. The peaks and troughs of HP requirement are then managed
by the battery level.

Makes sense to me anyway, there may well be a huge flaw I've not
thought of given no one is doing it that way

JL
(I'd imagine a 300 or 400cc diesel tuned for max efficiency and output
in a narrow rpm band would be more than sufficient for a prius sized
car if you run it continuously during operation - possibly even
continue to auto run after stopping until fully charged the same way a
turbo cooler run on works)
JL

 

You've totally missed my point - throttle response irrelevant - you'd
utilise a stationary motor diesel - one optimised for max efficiency
(max HP at min consumption) at a constant rpm. With appropriate
management of the battery levels you'd run it for extended periods
because you'd use a very small motor which wouldn't go anywhere near
being able to supply peak load, but would provide greater than
*average* load. That'd work because you'd run it constantly so in the
periods where a prius would be switching off the diesel would continue
to run and top up the level, and when you're driving at peak
acceleration you'd be gradually draining the batteries as the diesel
would only be supplying say 75% of the requirement.

For stop / start city driving it would be super efficient. It'd be
useless on a racetrack of course ;-)

JL

 

Apples with Oranges, 2 litre turbo diesel against 2 litre non turbo
petrol.

And no I still don't buy the argument that just because pretty much
all diesels come with a turbo that you should compare them to normally
aspirated petrol engines.

A turbo petrol of smaller capacity which puts out the same HP (a
fairer comparison) will do better around town (because it's idling at
the smaller capacity). I'd expect the diesel to be better on the
highway.

Alternatively a turbo petrol of the same cc's and turbo pressure will
put out considerably more HP for a less than proportionate increase in
consumption (ie say 50% increase in HP and 25% increase in consumption
- to explain the meaning not to specify the difference) - hence why I
suggest HP rather than turbo +cc's as a comparison.

There's pluses and minuses to both engine types but at least stop
being disingenuous !! ;-P

JL

 

You failed to read what I was suggesting.

I specifically suggested a better hybrid than a prius would be a
stationary diesel only used for charging the batteries, not for
driving the wheels.