"Dave Plowman (News)" wrote:

In article ,
Johannes wrote:
Strangely enough, cooling though the radiator is just as important as the
heating in the combustion for achieving high efficiency. You can only
extract mechanical energy between two temperatures; the larger the gap,
the more efficient.

That's a bit of an over simplification. Engines don't run at their most
efficient until up to temperature. Probably to do with proper atomisation
of the fuel.


Indeed, this is abstract thermodynamic theory that was fully developed in
the 19'th century. It is unrelated to a particular engine as long as it's
in the business of converting heat to mechanical energy. The maximum
possible efficiency of an engine is (T1-T2)/T1 .

On Sat, 24 Dec 2005 10:04:26 +0000, Andy Dingley
wrote:


Name one _car_ (as opposed to a boat) that uses a water-air intercooler.
[snip]

As standard? Erm... How about the Lotus Esprit Turbo?

http://www.mccullagh.org/image/10d-1...urbo-s4-4.html

Do I get a prize?

Cheers,

Colin.

The message
from marb contains these words:

Which recent cars do have chargecoolers, or even intake air coolers which
are cooled by the rad? I know none of mine have...


Near enough all turbo charged cars including diesels!

Not cooled by the radiator they don't.

--
Skipweasel
Never knowingly understood. (Ivor Cutler)

The message
from "Dave Plowman (News)" contains these words:

That's a bit of an over simplification. Engines don't run at their most
efficient until up to temperature. Probably to do with proper atomisation
of the fuel.

Partly that, but mostly because it's the difference between the incoming
cold charge and the hot burning that generates the power. Designers now
keep the engine as hot as practial in order to keep the gases as hot as
possible during the power stroke so that they're only cooled by
expansion instead of radiation/conduction/convection. It's the
efficiency of expanding the hot gases which drives the efficiency of the
engine as a whole.

Obviously there are many other considerations, but that's the
fundamental thermodynamic one.

--
Skipweasel
Never knowingly understood. (Ivor Cutler)

On Sat, 24 Dec 2005 10:23:45 +0000, Colin Stamp
wrote:

Name one _car_ (as opposed to a boat) that uses a water-air intercooler.
[snip]

As standard? Erm... How about the Lotus Esprit Turbo?

You see my point? Not many are there, and that one's mid-engined.
Presumably it's easier to deal with the extra heat capacity on the
existing radiator than to arrange ducting for an air-air intercooler.

Do I get a prize?

Leave a mince pie out and we'll see what the fat bloke can arrange.

On Sat, 24 Dec 2005 10:15:05 GMT, Johannes
wrote:

That's a bit of an over simplification. Engines don't run at their most
efficient until up to temperature. Probably to do with proper atomisation
of the fuel.


Indeed, this is abstract thermodynamic theory that was fully developed in
the 19'th century.

Why is that particularly relevant though? That deals with the
temperature of the working fluid, not the engine itself. A petrol car
engine might take several minutes to warm up properly, but the
combustion temperature is stable within seconds.

Andy Dingley wrote:

On Sat, 24 Dec 2005 10:15:05 GMT, Johannes
wrote:

That's a bit of an over simplification. Engines don't run at their most
efficient until up to temperature. Probably to do with proper atomisation
of the fuel.


Indeed, this is abstract thermodynamic theory that was fully developed in
the 19'th century.

Why is that particularly relevant though? That deals with the
temperature of the working fluid, not the engine itself. A petrol car
engine might take several minutes to warm up properly, but the
combustion temperature is stable within seconds.

This was in context of my original post; I wanted to emphasise that it
was a generalised assertion of the maximum possible efficiency. Other
factors may reduce the efficiency.

On Sat, 24 Dec 2005 10:47:05 +0000, Andy Dingley
wrote:

On Sat, 24 Dec 2005 10:23:45 +0000, Colin Stamp
wrote:

Name one _car_ (as opposed to a boat) that uses a water-air intercooler.
[snip]

As standard? Erm... How about the Lotus Esprit Turbo?

You see my point? Not many are there,

You only asked for one. Some people are never satisfied ;o)

and that one's mid-engined.
Presumably it's easier to deal with the extra heat capacity on the
existing radiator than to arrange ducting for an air-air intercooler.

The real reason they're so seldom used is that they're seldom needed.
They don't have many advantages over air-air intercoolers. The main
one is that the cooling airflow doesn't need to be anywhere near the
air to be cooled. That's what makes them attractive for cars like the
Esprit where there isn't much in the way of cool air available in the
engine compartment.

I'd also be surprised if the engine cooling system is used to dump the
heat. Surely that would end-up heating the charge air rather than
cooling it. At best, you'd end up with a 90C ish charge, which is
really dismal. More likely, the chargecooler[sic] would have it's own
radiator. The engine cooling system will still need to dump more heat
though because of the power increase provided by the denser charge
air.


Do I get a prize?

Leave a mince pie out and we'll see what the fat bloke can arrange.

He can sod off. The mince pies are all mine!

Cheers,

Colin.

On Thu, 22 Dec 2005 15:10:24 +0000, Chris Bacon wrote
(in message ):

[ Catalytic converters have little place in motoring in the UK. ]

Yes they do - as anyone who walks close to town traffic will know. You
can instantly tell an older non cat equipped car by the smell. And
it's not pleasant.

This is rubbish. Most cars are used for short journeys, during
which their catalytic converters do not work properly.

It would have to be a *very* short journey indeed. Most these days light
up very quickly.

How short a journey?

Probably improved in recent years, but I think you'll find that a significant
propertion of commute journeys do not heat the cat up to working temp at all
(especially in town/city driving when low average power is used). This is in
fact a significant factor in the fact that many cats are totally dead by the
first MOT test at 3 years old - 'crap' builds up on the matrix during these
short journeys, when the cat does 'light up' on the occasional hard
drive/longer journey then the crap burns off and causes the matrix to
overheat and disintegrate.

I didn't mention lead, just that finely divided platinum is being
emitted all over the place. Incidentally, lead-free fuel is quite
capable of being used in non-cat. cars, so I'm not sure what your
comment pertains to.

Not to mention that to make a cat work properly, excess fuel is burned to
create the right conditions in the exhaust. Yes, cats make cars burn more
fuel. Oh yes, and if cats hadn't been mandated then by now we'd probably have
some incredibly lean-burn engines using much less fuel than current engines -
but such work was abandoned as lean-burn doesn't work with cats.

What does a catalytic converter spit out then it's not yet
functioning well?

See above. But the same as a non cat engine.

With any reduction in fuel economy?

See above, if the cat wasn't fitted then the car might be burning less fuel
to start with !

"The3rd Earl Of Derby" wrote in message
. uk...
Dave Plowman (News) wrote:
In Autocar this week.

BMW are experimenting with using the waste heat from an IC engine to
produce steam which drives a motor attached to the main engine. On the
test bed they're getting a 15% saving in fuel consumption - at the
same time as more power and torque.

Seems it's not a new idea, but BMW reckon it is practical and should
be in production within 10 years.

When I was a nipper my old man was a tinkerer in electric motors and
generators and although this is very vague he put together on a piece of
wood a small cycle light generator a 12 or 24 volt motor(?) and
rechargable
battery connected together whereby the battery started the motor which in
turn rotated the generator wheel thus fed power to the battery for
charging
purposes, obviously there was some electronics in between which as i said
was very vague recollection

A Perpetual Motion Machine. I hope it worked. Some do, but can only turn
themsleves and produce no more power for other work.

"Ian Stirling" wrote in message
...

car engines are quite
inefficient (thermodynamically), and the
exhaust temperature (at the
exhaust valve) is around 700C.

Current car engines are about 25%
at best efficient, so 75% of power goes
out the exhaust pipe wasted.

No, 75% of "energy" is wasted.

"Aidan" wrote in message
oups.com...

Andy Dingley wrote:

BMW are experimenting with using the waste heat from an IC engine to
produce steam which drives a motor attached to the main engine.

http://www.gizmag.co.uk/go/4936/

Looking at the pics ( which aren't very clear & I haven't spent very
long looking) it seems they're using the heat from the catalytic
converter as a superheater.

My understanding was that a catalytic converter increased fuel
consumption by about 10%, whilst the heat generated in catalysing CO
into CO2 was sufficient to make it a fire hazard in dry grass. So now
the Germans have added on a steam engine which recovers 10% of the
efficiency.

I saw Maggie Thatcher (ex industrial chemist) on TV ranting about
catalytic converters, the only time I heard her speak sense. A more
cost-effective method of reducing emissions was the lean-burn engine,
which was both more efficient and less polluting that an un-catted
engine. I believe Rover had done much development on the lean-burn
technology, but that seems to have been scuttled after BMW's brief
period at the helm.

BL and Honda had much work on it. The problem was that all the world had
gone over to catalyst, so us and Japs had to follow. A bit like the VHS v
Betamax.

"Andy Dingley" wrote in message
...
On Wed, 21 Dec 2005 14:11:42 +0000 (GMT), "Dave Plowman (News)"
wrote:

BMW are experimenting with using the waste heat from an IC engine to
produce steam which drives a motor attached to the main engine.

http://www.gizmag.co.uk/go/4936/

A non starter. As much as 25% of an engines power may be to run the
ancillaries not to drive the wheels. This SteamCell is the size of a PC
tower and is very clean using external combustion and ceramic fibre burners.
They have installed these in buses and coaches, and leave the engine just to
turn the wheels with no fan belts on it at all. Then the overall emissions
are down, and overall efficiency up as this thing is well above 25%
efficient, more like 80%. It can actually drive a small car too.
http://www.enginion-ag.de/en/

It can also turn a genny to power and electric motor. This is viewed as
feasible and economical too. It can also run off natural gas and be used as
microCHP in a building.

Battery technology has come along, long way, to the point the electric car
is technologically here. Any other innovation is a stop-gap or a desperate
attempt at a comp[any which can't grasp the future. What have BMW ever
innovated that matters?

Using Lithium batteries in a car only 5%, or less, of the energy stored in
the vehicle is lost, while 75% of the energy in your tank is wasted. It is
more efficient overall to pour the fuel in a motor at a power station with
efficient combustion, energy re-claim and advanced scrubbers, which turns a
genny, which sends the electricity down a line, charges a vehicle battery
and runs the motor, rather than pour the fuel in the car directly. Also
they are 100% clean at point of burn.

"Aidan" wrote in message
oups.com...

Andy Dingley wrote:

BMW are experimenting with using the waste heat from an IC engine to
produce steam which drives a motor attached to the main engine.

http://www.gizmag.co.uk/go/4936/

Looking at the pics ( which aren't very clear & I haven't spent very
long looking) it seems they're using the heat from the catalytic
converter as a superheater.

It's overcomplex and cannot compete with the simplicity and efficiency of a
Toyota setup hybrid, which most major companies are adopting.

Doctor Drivel wrote:

"Ian Stirling" wrote in message
...

car engines are quite
inefficient (thermodynamically), and the
exhaust temperature (at the
exhaust valve) is around 700C.

Current car engines are about 25%
at best efficient, so 75% of power goes
out the exhaust pipe wasted.

No, 75% of "energy" is wasted.

75% of both.
Energy = power * time.

In article ,
Simon Hobson wrote:
Probably improved in recent years, but I think you'll find that a
significant propertion of commute journeys do not heat the cat up to
working temp at all (especially in town/city driving when low average
power is used). This is in fact a significant factor in the fact that
many cats are totally dead by the first MOT test at 3 years old -
'crap' builds up on the matrix during these short journeys, when the
cat does 'light up' on the occasional hard drive/longer journey then
the crap burns off and causes the matrix to overheat and disintegrate.

My first cat. car (94) was still on the original at 7 years old and
130,000 miles - most of those done by the first owner. I live in London
and have a pretty short journey to work - only about 4 miles. Nor have I
heard of it being common for cats. to fail by the first MOT. My present
car - an auto - stays in second gear at town speeds to speed warm up, then
reverts to normal.

--
*The problem with the world is that everyone is a few drinks behind *

Dave Plowman London SW
To e-mail, change noise into sound.

The message
from Ian Stirling contains these words:

Current car engines are about 25%
at best efficient, so 75% of power goes
out the exhaust pipe wasted.

No, 75% of "energy" is wasted.

75% of both.

I hate to agree with Dribble, particularly when he is only right by
accident, but in the instance above his answer does seem to fit the
facts. Some of the wasted energy departs via the radiator rather than
the exhaust pipe. :-)

BTW Dribble thought up a convincing definition for 'mountain' yet?

--
Roger Chapman
Seasons greetings to all, even Dribble.

In article ,
Simon Hobson wrote:
Not to mention that to make a cat work properly, excess fuel is burned
to create the right conditions in the exhaust.

Excess fuelling will kill a cat. in short order, surely? That's why you
have a lambda sensor to keep the fuelling constant once it's gone closed
loop?

--
*I'm not being rude. You're just insignificant

Dave Plowman London SW
To e-mail, change noise into sound.

Andy Dingley wrote:
On Sat, 24 Dec 2005 07:50:24 GMT, marb wrote:

Which recent cars do have chargecoolers, or even intake air coolers
which
are cooled by the rad? I know none of mine have...

Near enough all turbo charged cars including diesels!

Name one _car_ (as opposed to a boat) that uses a water-air intercooler.
Intercoolers are reasonably common (although by no means "near enough
all") but they're air-air intercoolers, not water-air.


Subrau Legacy

--
ThePunisher

On Fri, 23 Dec 2005 21:46:02 GMT, Johannes wrote:

Chris Bacon wrote:

Ian Stirling wrote:
Current car engines are about 25% at best efficient, so 75% of power goes
out the exhaust pipe wasted.

I thought most was lost through the radiator.

Strangely enough, cooling though the radiator is just as important as the
heating in the combustion for achieving high efficiency. You can only
extract mechanical energy between two temperatures; the larger the gap,
the more efficient.

Sadly however, on car, the radioator does notr cool the exhaust gasses.

So you are talking ********.

If te exgaust were dindensed in te raradiator, it woudl indeed enable a
more efficient engine to be produyced, but teh cat enbsures that the
exhaust temperetures are high enough to make this impossible

The message
from The Natural Philosopher contains these words:

If te exgaust were dindensed in te raradiator, it woudl indeed enable a
more efficient engine to be produyced, but teh cat enbsures that the
exhaust temperetures are high enough to make this impossible

Yuletide cheer got the better of your typing finger?

--
Skipweasel
Never knowingly understood. (Ivor Cutler)

On Sun, 25 Dec 2005 15:05:00 GMT, Guy King wrote:

The message
from The Natural Philosopher contains these words:

If te exgaust were dindensed in te raradiator, it woudl indeed enable a
more efficient engine to be produyced, but teh cat enbsures that the
exhaust temperetures are high enough to make this impossible

Yuletide cheer got the better of your typing finger?

And a stiff neck ;-)

On Mon, 26 Dec 2005 14:18:32 +0000, The Natural Philosopher
wrote:

On Sun, 25 Dec 2005 15:05:00 GMT, Guy King wrote:

The message
from The Natural Philosopher contains these words:

If te exgaust were dindensed in te raradiator, it woudl indeed enable a
more efficient engine to be produyced, but teh cat enbsures that the
exhaust temperetures are high enough to make this impossible

Yuletide cheer got the better of your typing finger?

And a stiff neck ;-)

You must learn to swallow those little blue tablets properly..... :-)


--

..andy

Andy Dingley ) gurgled happily, sounding much
like they were saying :

Which recent cars do have chargecoolers, or even intake air coolers
which are cooled by the rad? I know none of mine have...

Near enough all turbo charged cars including diesels!

Name one _car_ (as opposed to a boat) that uses a water-air
intercooler. Intercoolers are reasonably common (although by no means
"near enough all") but they're air-air intercoolers, not water-air.

OK, so you didn't like the answer of "Esprit", and you've ignored the other
answer of "Legacy". How about various Celicas?

Chris Bacon wrote:
Dave Fawthrop wrote:

IIRC only the maximum emissions of cars are limited, there is nothing
to say you *must* have catalytic converters.


AFAIK all new cars made since January 1993 *must* have a
catalytic converter fitted. Europead directive blah, unless
it's only UK law, which I doubt.

Nope. European law. I vaguely recall an article in 'Car Design and
Technology' magazine[1] in the '80s which said the law had been (badly)
written to require the use of an oxygen sensor and hence a cat and
stoichiometric(sp?) fuel/air ratio of 14.something to 1. Their view was
that lean-burn (20-25:1) was the better solution.

Alan

[1] Anyone remember that? Written from an engineering/technology
viewpoint rather than the What'll it do mister?/Let's see how sideways
we can get it 'round this bend type of mentality.

--
Warning! - This newsgroup may contain nuts....
Mail sent to this address might get read....Eventually

Alan Vann wrote:
Chris Bacon wrote:
Dave Fawthrop wrote:

IIRC only the maximum emissions of cars are limited, there is
nothing to say you *must* have catalytic converters.


AFAIK all new cars made since January 1993 *must* have a
catalytic converter fitted. Europead directive blah, unless
it's only UK law, which I doubt.

Nope. European law. I vaguely recall an article in 'Car Design and
Technology' magazine[1] in the '80s which said the law had been
(badly) written to require the use of an oxygen sensor and hence a
cat and stoichiometric(sp?) fuel/air ratio of 14.something to 1.
Their view was that lean-burn (20-25:1) was the better solution.

Alan

[1] Anyone remember that? Written from an engineering/technology
viewpoint rather than the What'll it do mister?/Let's see how sideways
we can get it 'round this bend type of mentality.

I remember the concept well - lean burn engines were coming along well but
only the European manufacturers had engines close to production which could
meet the proposed emissions, so US pressure was applied to make cats the
only allowed solution...

Or something.

In article ,
PC Paul wrote:
I remember the concept well - lean burn engines were coming along well
but only the European manufacturers had engines close to production
which could meet the proposed emissions, so US pressure was applied to
make cats the only allowed solution...

Or something.

There is no legal requirement for a cat. - merely to pass the emissions
regs. How it is done doesn't matter. And some engines get very close
without a cat. IIRC, the problem with lean burn engines is high NOX output
- although CO can be low. CO2 is also lower, but this isn't tested.

--
*They call it PMS because Mad Cow Disease was already taken.

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 28 Dec 2005 23:52:42 +0000 (GMT), Dave Plowman (News) wrote:

In article ,
PC Paul wrote:
I remember the concept well - lean burn engines were coming along well
but only the European manufacturers had engines close to production
which could meet the proposed emissions, so US pressure was applied to
make cats the only allowed solution...

Or something.

There is no legal requirement for a cat. - merely to pass the emissions
regs. How it is done doesn't matter. And some engines get very close
without a cat. IIRC, the problem with lean burn engines is high NOX output
- although CO can be low. CO2 is also lower, but this isn't tested.

That is my understanding as well.

The furore was about the fact that the emissions tests are done with a
fully warm engine: there is no requirement to meet them for what, in a cold
country, is up to the first 5 miles off normal driving.

Lean burn would have reduced unburnt fuel emmissions somewhat more in this
scenario, alledgedly.

In article ,
The Natural Philosopher wrote:
The furore was about the fact that the emissions tests are done with a
fully warm engine: there is no requirement to meet them for what, in a
cold country, is up to the first 5 miles off normal driving.

It was the case with early cats. but modern ones fire up much earlier.
And the US of A - natural home of the cat. - has rather colder weather
than us in many parts.

--
*Why is "abbreviated" such a long word?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
PC Paul wrote:
I remember the concept well - lean burn engines were coming along well
but only the European manufacturers had engines close to production
which could meet the proposed emissions, so US pressure was applied to
make cats the only allowed solution...

There is no legal requirement for a cat. - merely to pass the emissions
regs.

But they are required by law to be fitted to new cars sold after 1992 IIRC.

Will a car bought 3 years ago pass an MOT without a catalytic converter
being fitted?

Dave Plowman (News) wrote:
The Natural Philosopher wrote:

The furore was about the fact that the emissions tests are done with a
fully warm engine: there is no requirement to meet them for what, in a
cold country, is up to the first 5 miles off normal driving.

It was the case with early cats. but modern ones fire up much earlier.

How much earlier? How long does it take?


And the US of A - natural home of the cat. - has rather colder weather
than us in many parts.

And far longer "normal journey lengths", so the proportion of time
spent driving with a non-functioning catalytic converter is far less.

In article ,
Chris Bacon wrote:
There is no legal requirement for a cat. - merely to pass the emissions
regs.

But they are required by law to be fitted to new cars sold after 1992 IIRC.

No - it's simply the emissions regs were tightened then which means in
practice a cat is needed.

Will a car bought 3 years ago pass an MOT without a catalytic converter
being fitted?

They are designed to pass the emissions regs with one so unlikely.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Chris Bacon wrote:
And the US of A - natural home of the cat. - has rather colder weather
than us in many parts.

And far longer "normal journey lengths", so the proportion of time
spent driving with a non-functioning catalytic converter is far less.

Those 'longer journeys' are likely to be out of town. Plenty will do short
town trips as in the UK.

--
*Reality? Is that where the pizza delivery guy comes from?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote, munging the attributions:
Chris Bacon wrote:
And the US of A - natural home of the cat. - has rather colder weather
than us in many parts.

And far longer "normal journey lengths", so the proportion of time
spent driving with a non-functioning catalytic converter is far less.

Those 'longer journeys' are likely to be out of town. Plenty will do short
town trips as in the UK.

Obviously, but on average the journeys are likely to be longer.


So, how long *does* it take for a catalytic converter to "fire
up" and start working properly?

In article ,
Chris Bacon wrote:
So, how long *does* it take for a catalytic converter to "fire
up" and start working properly?

It will depend on how the car is driven and what the external temperature
is. But say about 1/2 a mile.

--
*Happiness is seeing your mother-in-law on a milk carton

Dave Plowman London SW
To e-mail, change noise into sound.

John Wright ) gurgled happily, sounding much like
they were saying :

But they are required by law to be fitted to new cars sold after
1992 IIRC.

No - it's simply the emissions regs were tightened then which means in
practice a cat is needed.

They were tightened so that only a cat equipped engine would pass -
thus ending research in the UK into Lean Burn engines which would not
pass the emissions regulations at that time.

Not quite - a cat was specifically legislated to be fitted to all new
petrol cars, and that was what killed "proper" lean-burn, as the cat is
based upon 14:1 air:fuel - requiring the use of the lambda sensor to keep
it there.

The MOT doesn't *specifically* require the fitment of a cat, but the
emission requirements would be very difficult (at least) to meet without
one.

In article ,
John Wright wrote:
No - it's simply the emissions regs were tightened then which means in
practice a cat is needed.

They were tightened so that only a cat equipped engine would pass -
thus ending research in the UK into Lean Burn engines which would not
pass the emissions regulations at that time.

If there was a possibility of them passing after more development, why
would this stop if they had other benefits?

--
*Proofread carefully to see if you any words out or mispeld something *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote
John Wright wrote:
No - it's simply the emissions regs were tightened then which means in
practice a cat is needed.

They were tightened so that only a cat equipped engine would pass -
thus ending research in the UK into Lean Burn engines which would not
pass the emissions regulations at that time.

If there was a possibility of them passing after more development, why
would this stop if they had other benefits?

It didn't stop development. Diesels are lean burn.

Though it is an oddity of the regs that, rather than having blanket
regulations for particular classes of vehicle, that it distinguished
between different fuel types.

Oh, and LB can't meet the NOx regulations specified for petrol engines.

DavidR ) gurgled happily, sounding much like they
were saying :

Though it is an oddity of the regs that, rather than having blanket
regulations for particular classes of vehicle, that it distinguished
between different fuel types.

It's an oddity in that it says "This is what you do to the exhaust" rather
than "This is what you should be shoving out the exhaust" - legislating the
means not the target.

A hint of lobbying from the precious metal miners, p'raps?

Oh, and LB can't meet the NOx regulations specified for petrol engines.

It can't... at the state of development it was left in when compulsory cats
killed it.

In article ,
DavidR wrote:
If there was a possibility of them passing after more development, why
would this stop if they had other benefits?

It didn't stop development. Diesels are lean burn.

The power output of a diesel is controlled by the amount of fuel injected.
Not the same thing.

--
*Many people quit looking for work when they find a job *

Dave Plowman London SW
To e-mail, change noise into sound.