OT: 20 & 30mph pollution differences

Tony Raven said:

It will as long as you keep giving it the oxygen it craves. Trust me,
the only way to get rid of trolls is to ignore them and they will
eventually lose interest in talking to themselves. Unfortunately quite a
few people here think trolls are redeemable by rational argument and
persist with Mormon zeal in trying to convert them. But all they are
doing is fortifying them and irritating the rest.

It appears that the annoying little critter hadn't read my suggestion
to Elyob (even though the sad entity responded to me), and thought
that Greenwich Cyclists were lobbying for a restriction of speed in
Richmond Park.

The pitiful failure of Darwinism has issued an apology of sorts, and I
will refrain from responding to its idiocy in future.

Tom Crispin said:

The pitiful failure of Darwinism

Do we know it's reproduced and passed on its preference for "radical
solutions to transport problems" to its offspring? ;-/

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Tom Crispin said:

It appears that the annoying little critter hadn't read my suggestion to
Elyob (even though the sad entity responded to me), and thought that
Greenwich Cyclists were lobbying for a restriction of speed in Richmond
Park.

Troll modus operandi much to learn you have, young Crispin.

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell

Tony Raven said:

Troll modus operandi

No. The spewing forth of a reluctant admission of failure to pay
attention to what had been written suggests a humbling embarrassment
on the part of the miserable entity.

Quoted message said:

young Crispin

I wish!

My entering middle age was celebrated on the summit of Tryfan on 21
December last year.

Peter Clinch said:

Tom Crispin said:

The pitiful failure of Darwinism

Do we know it's reproduced and passed on its preference for "radical
solutions to transport problems" to its offspring? ;-/

Ahhh! You have a good point. Darwinism may have made it so utterly
repulsive to all creatures that, even if it is not sterile, there will
be no living being willing submit to its carnal desire, and if forced
to submit will not carry its offspring to full term without
termination or suicide.

Tony Raven said the following on 22/08/2007 12:47:

Quoted message said:

Sometimes though they make an error on the order and fit them anyway:
http://www.bbspot.com/News/2003/11/bmw.html

Brilliant!

--
Paul Boyd
http://www.paul-boyd.co.uk/

On 22 Aug, 12:07, _ <[email hidden]>

Quoted message said:

Tony Raven said:

On Wed, 22 Aug 2007 00:27:07 +0100, Tom Crispin wrote:

Quoted message said:

Quoted message said:

On Tue, 21 Aug 2007 17:31:50 -0500, Tony Raven

Quoted message said:

Quoted message said:

>You do know what a Troll is?

Quoted message said:

Quoted message said:

It persists.

Quoted message said:

It will as long as you keep giving it the oxygen it craves. Trust me,
the only way to get rid of trolls is to ignore them and they will
eventually lose interest in talking to themselves. Unfortunately quite a
few people here think trolls are redeemable by rational argument and
persist with Mormon zeal in trying to convert them. But all they are
doing is fortifying them and irritating the rest.

Over the past few months the understanding of the newsgroup readers has
improved quite a bit - to check this, look at any of the threads in which
TrollB appears; you will find that almost always when he posts, no one
replies. I don't know whether this is filtering or or good behaviour, but
in either case, it has improved the readability of the threads greatly.

Perhaps regular readers might continue to (gently) remind new posters that
yes, we know here's a Troll here, and we know he'll say anything to be
naughty, but the best thing is to do is ignore him, and he will eventually
go be naughty in front of someone else.

That's great coming from someone who doesnt even have a name. lololol

Paul Boyd usenet.is.worse@plusnet said:

Tony Raven said the following on 22/08/2007 12:47:

Quoted message said:

Sometimes though they make an error on the order and fit them anyway:
http://www.bbspot.com/News/2003/11/bmw.html

Brilliant!

--
Paul Boydhttp://www.paul-boyd.co.uk/

It was in America...

On 22 Aug, 06:40, Zog The Undeniable <[email hidden]> wrote:
?It's a balance between many factors such as most efficient

Quoted message said:

rpm and throttle position,

Most efficient throttle position is fully open, not sure how that
compares to fuel use though lol

"elyob" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi,

Quoted message said:

Just about to respond to a letter in my local rag r.e. Richmond Park.

The writer claims that driving at 20mph creates more pollution, he
doesn't back it up and wondered if there is any evidence to the
contrary?

Quoted message said:

A 1982 Citroen BX1600
speed 4th 5th
30 48.4 55.4
40 46.1 51.7
50 40.8 47.4
60 36.4 41.5
70 31.9 35.9
80 27.1 30.0

A good demonstration, I think, that fuel consumed is directly proportional
to mechanical losses, not some variation in combustion "efficiency". The
speed shows tyre, transmission and air, the gear difference shows
underbonnet losses - ancillaries and friction within the engine.

On the face of it, 5th at 30 might just pip 20 in 4th.

DavidR said:

"elyob" <[email hidden]> wrote in message

news:[email hidden]...

Quoted message said:

Hi,
Just about to respond to a letter in my local rag r.e. Richmond Park.

The writer claims that driving at 20mph creates more pollution, he
doesn't back it up and wondered if there is any evidence to the
contrary?

A 1982 Citroen BX1600
speed 4th 5th
30 48.4 55.4
40 46.1 51.7
50 40.8 47.4
60 36.4 41.5
70 31.9 35.9
80 27.1 30.0

A good demonstration, I think, that fuel consumed is directly proportional
to mechanical losses, not some variation in combustion "efficiency". The
speed shows tyre, transmission and air, the gear difference shows
underbonnet losses - ancillaries and friction within the engine.

On the face of it, 5th at 30 might just pip 20 in 4th.

Im fascinated to find out, where are your figures from? I dont know
any vehicle manufacturer that provided that much info, especially not
in 1982. And IIRC the 82 BX is a carb'd car, not FI which is a whole
different kettle of fish entirely and not overly relevant? Combustion
efficiency does change with revs, noticably so - I have some fuel use
charts from an engine on the dyno in our lab somewhere, will try to
dig it out. Its also linked to throttling losses, which increase
vastly at low-rev-low-load situations.

know...http://www.highwaycode.gov.uk/03.htm said the following

Quoted message said:

It was in America...

Yes?

--
Paul Boyd
http://www.paul-boyd.co.uk/

Dylan Smith said:

Go much faster, and fuel economy quickly begins to fall.

My current car has a computer thingy that tells you how your fuel
economy is doing.
I find the biggest difference on motorways is having a roof box on
top, the extra drag is terrible for the consumption at speed.

On Thu, 23 Aug 2007 00:28:18 -0700, POHB <[email hidden]>

Quoted message said:

Dylan Smith said:

Go much faster, and fuel economy quickly begins to fall.

My current car has a computer thingy that tells you how your fuel
economy is doing.
I find the biggest difference on motorways is having a roof box on
top, the extra drag is terrible for the consumption at speed.

Depends a lot on the model (of box and car). I have a Volvo V70XC
which we use a lot in Winter for skiing, so the roof box
http://www.thule.com/Thule/ProductPage____45931.aspx is permanently
mounted from November to May. Oddly enough, the effects on fuel
consumption are marginal at best, which I put down mainly to the box's
aerodynamic shape. It could, of course, be mitigated by the fact that
the roof rails are a permanent fixture, so there's already some drag
there, although they're of the built-in, aerodynamic variety.

--
Ace in Alsace - brucedotrogers a.t rochedotcom

CoyoteBoy said:

On 22 Aug, 22:29, "DavidR" <[email hidden]> wrote:

Quoted message said:

Quoted message said:

A 1982 Citroen BX1600
speed 4th 5th
30 48.4 55.4
40 46.1 51.7
50 40.8 47.4
60 36.4 41.5
70 31.9 35.9
80 27.1 30.0

A good demonstration, I think, that fuel consumed is directly proportional
to mechanical losses, not some variation in combustion "efficiency". The
speed shows tyre, transmission and air, the gear difference shows
underbonnet losses - ancillaries and friction within the engine.

On the face of it, 5th at 30 might just pip 20 in 4th.

Im fascinated to find out, where are your figures from? I dont know
any vehicle manufacturer that provided that much info, especially not
in 1982.

I'm sure this sort of data was in the manuals for both my Peugeot 106
(1996) and Renault Mégane (1998). I've no evidence as I no longer
possess either of the cars but it may be a French thing.

Cheers,
Luke

--
Red Rose Ramblings, the diary of an Essex boy in
exile in Lancashire <http://www.shrimper.org.uk>

The other view point, there is one you

know...urlhttp://www.highwaycode.gov.uk/03.htm/url said:

On 22 Aug, 12:07, _ <[email hidden]>

Quoted message said:

Tony Raven said:

On Wed, 22 Aug 2007 00:27:07 +0100, Tom Crispin wrote:

Quoted message said:

>On Tue, 21 Aug 2007 17:31:50 -0500, Tony Raven

Quoted message said:

>>You do know what a Troll is?

Quoted message said:

>It persists.

Quoted message said:

It will as long as you keep giving it the oxygen it craves. Trust me,
the only way to get rid of trolls is to ignore them and they will
eventually lose interest in talking to themselves. Unfortunately quite a
few people here think trolls are redeemable by rational argument and
persist with Mormon zeal in trying to convert them. But all they are
doing is fortifying them and irritating the rest.

Over the past few months the understanding of the newsgroup readers has
improved quite a bit - to check this, look at any of the threads in which
TrollB appears; you will find that almost always when he posts, no one
replies. I don't know whether this is filtering or or good behaviour, but
in either case, it has improved the readability of the threads greatly.

Perhaps regular readers might continue to (gently) remind new posters that
yes, we know here's a Troll here, and we know he'll say anything to be
naughty, but the best thing is to do is ignore him, and he will eventually
go be naughty in front of someone else.

That's great coming from someone who doesnt even have a name. lololol

You don't have to try very hard to get their email address though, Dewi.
That's usually an indicator of good faith.
Roger

Roger Thorpe said:

The other view point, there is one you
know...

Quoted message said:

That's great coming from someone who doesnt even have a name. lololol

You don't have to try very hard to get their email address though, Dewi.
That's usually an indicator of good faith.

And it was rich coming from a nym shifting troll!

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell

On 23 Aug, 09:47, [email hidden] (Ekul

Namsob) said:

CoyoteBoy said:

DavidR said:

A 1982 Citroen BX1600
speed 4th 5th
30 48.4 55.4
40 46.1 51.7
50 40.8 47.4
60 36.4 41.5
70 31.9 35.9
80 27.1 30.0

Quoted message said:

Quoted message said:

A good demonstration, I think, that fuel consumed is directly proportional
to mechanical losses, not some variation in combustion "efficiency". The
speed shows tyre, transmission and air, the gear difference shows
underbonnet losses - ancillaries and friction within the engine.

Quoted message said:

Quoted message said:

On the face of it, 5th at 30 might just pip 20 in 4th.

Quoted message said:

Im fascinated to find out, where are your figures from? I dont know
any vehicle manufacturer that provided that much info, especially not
in 1982.

I'm sure this sort of data was in the manuals for both my Peugeot 106
(1996) and Renault Mégane (1998). I've no evidence as I no longer
possess either of the cars but it may be a French thing.

Cheers,
Luke

--
Red Rose Ramblings, the diary of an Essex boy in
exile in Lancashire <http://www.shrimper.org.uk>

Just looking through my peugeot 205 (92) manual/handbook - cant see
anything like that.

"CoyoteBoy" <[email hidden]> wrote

Quoted message said:

DavidR said:

"elyob" <[email hidden]> wrote in message

news:[email hidden]...

Quoted message said:

Hi,
Just about to respond to a letter in my local rag r.e. Richmond Park.

The writer claims that driving at 20mph creates more pollution, he
doesn't back it up and wondered if there is any evidence to the
contrary?

A 1982 Citroen BX1600
speed 4th 5th
30 48.4 55.4
40 46.1 51.7
50 40.8 47.4
60 36.4 41.5
70 31.9 35.9
80 27.1 30.0

A good demonstration, I think, that fuel consumed is directly
proportional
to mechanical losses, not some variation in combustion "efficiency". The
speed shows tyre, transmission and air, the gear difference shows
underbonnet losses - ancillaries and friction within the engine.

On the face of it, 5th at 30 might just pip 20 in 4th.

Im fascinated to find out, where are your figures from?

An Autocar test. They used to do this regularly but I only have similar
data for a Polo.

Quoted message said:

I dont know
any vehicle manufacturer that provided that much info, especially not
in 1982. And IIRC the 82 BX is a carb'd car, not FI which is a whole
different kettle of fish entirely and not overly relevant?

Fueling is more accurate and but I can't see the principles changing. The
main differerence must be air
conditioning and other loads which are time based, not distance based so
there will be a speed below which the energy consumed by aircon will rise
more than the reduced tractive demand.

Quoted message said:

Combustion
efficiency does change with revs, noticably so - I have some fuel use
charts from an engine on the dyno in our lab somewhere, will try to
dig it out. Its also linked to throttling losses, which increase
vastly at low-rev-low-load situations.

Indeed. But I was quite deliberate with my use of the word 'combustion',
rather than 'engine' efficiency.. Let me take you through my thinking.

A mixture burns and delivers an amount of energy. Some is imparted to the
piston as mechanical energy, and some directly lost as heat. The energy
that comes out of the crank is less than that imparted on the piston. The
pumping action is performed by piston movement so is purely mechanical.

The engine has other losses that are essential for its operation -
piston/cylinder friction, bearings, valves, pumps and belts/chains/gears.
These losses are predominantly proportional to engine speed. More is usef
by underbonnet operation of the car - alternator, aircon & steering. These
have loads that vary with demand and journey time, not journey distance, as
well as drive losses predominantly associated with engine speed.

So now we get to traction - transmission and tyre losses are distance based
(transmission may have an engine speed component too) and aero load which
is related to distance and provides the only component related to road
speed.

Chuck all that into the pot and gas needs to be pumped through the engine
in proportion to it all - which adds another loss.

Phew!

One final thought; since the higher revs of a lower gear cause more
frictional losses, more airflow is required to deliver a given traction
power. The throttle should therefore be wider in a lower gear, producing
less throttling loss...