Discussion:
[EE] Simple fuel-saver, so they say
(too old to reply)
Jinx
2007-06-27 09:35:37 UTC
Permalink
I saw this advertised on TV today by a NZ motoring retail
chain (Repco)

http://www.hiclone.co.nz/

Interesting that it was the only item in the ad accompanied
by "100% money-back guarantee", although that could be
just repeating Hiclone's policy and not intended to imply
any dubious claims

It seems too good to be true (always a red flag). By simply
swirling the air going into the carburettor, 13-15% fuel savings
and more power, as reported by customers

I'd like to believe it, but is this yet another leg-pull ? And it
doesn't look like $169 worth either, although what does
"worth mean"

When I first heard the name, Magnetronic, I thought, 'allo,
what's all this then. But the name has seemingly nothing to
with the BS, and proven BS at that, fuel savers that claim
magnets do something magical to petrol

I'm not a motor engineer, but if it's as easy as a little time with
some thin sheet metal and a pair of snips, wouldn't it be more
common, even mandatory, on motor engines ? I know that
carburettors evolve, but 15% improvement in one go with a
few vanes ?
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Jinx
2007-06-27 09:56:58 UTC
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Identical to "patented" Hiclone

http://tornadofuelsaver.com/

Sigh, sucked in again

Someone took the trouble to compare

http://www.salemboysauto.com/tornado.htm

Found a few others, all say the same. Junk

http://www.toyota-4runner.org/showthread.php?s=414d8ec9bbdf1e61c8061d7e215e0
b16&postid=212735

I can't imagine how much more mixing one of these simple
vortex things could do AFTER a turbo-charger
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Roy
2007-06-27 18:50:07 UTC
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Send it to the "Fair Go" TV producers.
_______________________________________

Roy Hopkins ZL2RJH
Tauranga
New Zealand
_______________________________________
-----Original Message-----
Of Jinx
Sent: Wednesday, 27 June 2007 9:57 p.m.
To: pic microcontroller discussion list
Subject: Re: [EE] Simple fuel-saver, so they say
Identical to "patented" Hiclone
http://tornadofuelsaver.com/
Sigh, sucked in again
Someone took the trouble to compare
http://www.salemboysauto.com/tornado.htm
Found a few others, all say the same. Junk
http://www.toyota-
4runner.org/showthread.php?s=414d8ec9bbdf1e61c8061d7e215e0
b16&postid=212735
I can't imagine how much more mixing one of these simple
vortex things could do AFTER a turbo-charger
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Jinx
2007-06-28 01:23:26 UTC
Permalink
Post by Roy
Send it to the "Fair Go" TV producers.
It seems such a blantant waste of people's time and money
I feel I should do something
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Michael Rigby-Jones
2007-06-27 10:05:58 UTC
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-----Original Message-----
On Behalf Of Jinx
Sent: 27 June 2007 10:36
To: pic microcontroller discussion list
Subject: [EE] Simple fuel-saver, so they say
I saw this advertised on TV today by a NZ motoring retail
chain (Repco)
http://www.hiclone.co.nz/
Interesting that it was the only item in the ad accompanied
by "100% money-back guarantee", although that could be
just repeating Hiclone's policy and not intended to imply
any dubious claims
It seems too good to be true (always a red flag). By simply
swirling the air going into the carburettor, 13-15% fuel
savings and more power, as reported by customers
If it looks too good to be true, it probably is...

They don't work, as most reasonably intelligent people would suspect. A car magazine over here tested a very simmilar product, and measured only power loss. With the amount of swirl/tumble given to the mixture as it goes through the inlet of port of a cylinder, stiring the air a little bit at the air intake is simply not going to do anything (a fart in a hurricane springs to mind). If it did, you'd expect with the millions of $'s of research they spend, that car manufacturers would have adopted this years ago. If something that could literaly be made for a few cents could even give a fraction of the claimed benefits, they would be fitting them.

It's quite incredible just how many snake oil products exist in the automotive sector. Do people become more guilible after buying a car?

Mike

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Jinx
2007-06-27 10:21:01 UTC
Permalink
Do people become more guilible after buying a car ?
I very nearly did. After being carless for many many years
and ready to get one back on the road, my ears perked up.
Now I'll take a step back and a deep breath before reaching
for the $$

Most instructive for saving money were 3 demos

Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
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Tony Smith
2007-06-27 14:50:23 UTC
Permalink
Post by Jinx
Most instructive for saving money were 3 demos
Jeremy Clarkson's London-Edinburgh-London trip in a V8 on one
tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
In the second round of tailgate testing, there was a rather neat
demonstration of E=MV^2, otherwise known as 'going twice as fast takes four
times the effort'.

They ran the test at ~50 MPH (55?), and used 5 gallons or so. The next run
was at 25 MPH, and only used 1.25 gallons. (#s might off a bit...)

They never commented on it, but it was interesting to see a 'real life'
example.

Tony
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Dave Tweed
2007-06-27 21:11:53 UTC
Permalink
Post by Tony Smith
Post by Jinx
Most instructive for saving money were 3 demos
Jeremy Clarkson's London-Edinburgh-London trip in a V8 on one
tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
In the second round of tailgate testing, there was a rather neat
demonstration of E=MV^2, otherwise known as 'going twice as fast
takes four times the effort'.
They ran the test at ~50 MPH (55?), and used 5 gallons or so.
The next run was at 25 MPH, and only used 1.25 gallons. (#s
might off a bit...)
They never commented on it, but it was interesting to see a 'real
life' example.
That has nothing to do with e = 0.5*m*v^2 (instantaneous energy),
and everything to do with the fact that most forms of resistance
(air resistance, rolling resistance, etc.) are proportional to v^2.
This means that the total energy (work) required to travel a given
distance tends to be proportional to v^2, and the power required
(work per unit time) is proportional to v^3.

-- Dave Tweed
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Rich
2007-06-27 22:33:33 UTC
Permalink
I drive with the tailgate down when I use the pickup unloaded. It does save
fuel because up, it can scoop up enough air pressure at 50 mph to cause
significant drag. I have seen some kind of rubber or polymer sheet on some
pickups with big holes in the sheet stretched across the back, and no
tailgate. I assume it is intended to reduce drag but at higher speeds it
seems that perhaps some significant drag may develop to obviate the purpose.


----- Original Message -----
From: "Dave Tweed" <pic-wLJDi8KGRvzQT0dZR+***@public.gmane.org>
To: "'Microcontroller discussion list - Public.'" <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 5:11 PM
Subject: RE: [EE] Simple fuel-saver, so they say
Post by Dave Tweed
Post by Tony Smith
Post by Jinx
Most instructive for saving money were 3 demos
Jeremy Clarkson's London-Edinburgh-London trip in a V8 on one
tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
In the second round of tailgate testing, there was a rather neat
demonstration of E=MV^2, otherwise known as 'going twice as fast
takes four times the effort'.
They ran the test at ~50 MPH (55?), and used 5 gallons or so.
The next run was at 25 MPH, and only used 1.25 gallons. (#s
might off a bit...)
They never commented on it, but it was interesting to see a 'real
life' example.
That has nothing to do with e = 0.5*m*v^2 (instantaneous energy),
and everything to do with the fact that most forms of resistance
(air resistance, rolling resistance, etc.) are proportional to v^2.
This means that the total energy (work) required to travel a given
distance tends to be proportional to v^2, and the power required
(work per unit time) is proportional to v^3.
-- Dave Tweed
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Jinx
2007-06-27 23:03:47 UTC
Permalink
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It
does save fuel because up, it can scoop up enough air pressure at
50 mph to cause significant drag
Mythbusters claimed that with the tailgate down, the vortex behind
the cab disappears. According to the pick-up manufacturer (smoke
trail test film), air coming over the cab roof bounces off that vortex,
resulting in less drag

http://www.cartalk.com/content/columns/Archive/1997/October/05.html

As they say there, it's counter-intuitive

Not that I'm doubting your results, you know your vehicle and
have the numbers
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Rich
2007-06-28 04:53:33 UTC
Permalink
Interesting because I actually realized increased mileage with the TG down.
I have not modeled the air currents with "smoke" but I did fill the gas tank
and check the mileage. I got between 3 and 5 miles per gallon better with
the tail down at different times. I'm one of those people that saves
receipts and write the mileage down on it so when I fill the tank again I
can calculate the mileage. But I don't do all highway driving. I get about
20 mpg plus or minus on my V6 in 2W HD. I never checked it in 4W HD or 4W
LD. I only use 4W LD to pull the backhoe or trailer.
I wonder if I were to put NTC thermistors in strategic places and pulse
them to avoid self heating error, could I collect the air flow measurements
with the TG up and TG down? Also if I correlate the airflow at those points
with the velocity of the vehicle could I actually model the fluid
kinematics? And, if the drag is increased with the TG down to the extent
that it increases fuel consumption it would seem that additional energy
would be required from the engine; similar to turning on the head lamps or
air conditioning. Could the tach to speed ratio be recorded in continuous
real time with the TG up versus TG down? Of course, the delta drag may be
too insufficient to cause a measurable delta RPM. It could be fun to do
some of this. Just a kind of fun project with no pressure to meet a dead
line.




----- Original Message -----
From: "Jinx" <joecolquitt-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 7:03 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Jinx
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It
does save fuel because up, it can scoop up enough air pressure at
50 mph to cause significant drag
Mythbusters claimed that with the tailgate down, the vortex behind
the cab disappears. According to the pick-up manufacturer (smoke
trail test film), air coming over the cab roof bounces off that vortex,
resulting in less drag
http://www.cartalk.com/content/columns/Archive/1997/October/05.html
As they say there, it's counter-intuitive
Not that I'm doubting your results, you know your vehicle and
have the numbers
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Alan B. Pearce
2007-06-28 12:53:15 UTC
Permalink
Post by Rich
Interesting because I actually realized increased mileage with the TG down.
Perhaps you should consider the sports cars that have a wind screen behind
the seats for top down running - the effect is quite dramatic if a long
haired person is sitting in the seat, with the screen not present their hair
gets blown all over the place, with the screen up it is controllable.
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Matthew Mucker
2007-06-28 17:33:49 UTC
Permalink
Also, in the case of an accident, the vehicle has a lot more structural
integrity with the tailgate up.

----- Original Message -----
From: "Jinx" <joecolquitt-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 6:03 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Jinx
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It
does save fuel because up, it can scoop up enough air pressure at
50 mph to cause significant drag
Mythbusters claimed that with the tailgate down, the vortex behind
the cab disappears. According to the pick-up manufacturer (smoke
trail test film), air coming over the cab roof bounces off that vortex,
resulting in less drag
http://www.cartalk.com/content/columns/Archive/1997/October/05.html
As they say there, it's counter-intuitive
Not that I'm doubting your results, you know your vehicle and
have the numbers
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Rich
2007-07-02 07:04:38 UTC
Permalink
An excellent point.


----- Original Message -----
From: "Matthew Mucker" <matthew-QZHfmXwWthCsTnJN9+***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 1:33 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Matthew Mucker
Also, in the case of an accident, the vehicle has a lot more structural
integrity with the tailgate up.
----- Original Message -----
Sent: Wednesday, June 27, 2007 6:03 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Jinx
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It
does save fuel because up, it can scoop up enough air pressure at
50 mph to cause significant drag
Mythbusters claimed that with the tailgate down, the vortex behind
the cab disappears. According to the pick-up manufacturer (smoke
trail test film), air coming over the cab roof bounces off that vortex,
resulting in less drag
http://www.cartalk.com/content/columns/Archive/1997/October/05.html
As they say there, it's counter-intuitive
Not that I'm doubting your results, you know your vehicle and
have the numbers
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Jeff Findley
2007-06-29 20:55:56 UTC
Permalink
Post by Jinx
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It
does save fuel because up, it can scoop up enough air pressure at
50 mph to cause significant drag
Mythbusters claimed that with the tailgate down, the vortex behind
the cab disappears. According to the pick-up manufacturer (smoke
trail test film), air coming over the cab roof bounces off that vortex,
resulting in less drag
http://www.cartalk.com/content/columns/Archive/1997/October/05.html
As they say there, it's counter-intuitive
Not that I'm doubting your results, you know your vehicle and
have the numbers
This was known to be true before Mythbusters, but it is a bit counter
intuitive and may not apply equally to all makes and models due to different
bed lengths and other small design changes between models. Small changes
can do big things to aerodynamics, especially if a small change moves where
a boundary layer is tripped to turbulent flow.

As far as the show goes, I thought they had a Ford engineer on there
explaining the effect. I'd expect modern vehicles like the newest Ford F150
to be designed to get the best mileage with the tailgate up. But even
better than tailgate up or down would likely be an aftermarket bed cover.

Jeff
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Nate Duehr
2007-06-27 23:17:30 UTC
Permalink
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It does save
fuel because up, it can scoop up enough air pressure at 50 mph to cause
significant drag. I have seen some kind of rubber or polymer sheet on some
pickups with big holes in the sheet stretched across the back, and no
tailgate. I assume it is intended to reduce drag but at higher speeds it
seems that perhaps some significant drag may develop to obviate the purpose.
This is exactly what MythBusters disproved.

Having the tailgate up creates a vortex behind the cab to the rear of
the vehicle and actually creates LESS drag when the air flowing over it
of the main airstream interacts with the vortex instead of dragging
along the bed of the vehicle. A "buffer zone" of circular air motion,
so to speak.

The various "remove the tailgate" or "leave it down" products are snake
oil. Those netting-across-the-back products were proven in the show (as
was leaving the tailgate down) to have LOWER gas mileage than leaving it up.

Do your own tests (as they recommended) scientifically if you don't
believe them, but they did a pretty good job of making the tests fair,
and tailgate up won all categories.

Nate
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Rich
2007-06-28 05:57:47 UTC
Permalink
The drag issue is key issue. If there is more drag you need more energy to
overcome it. I would like to see the smoke test they ran.


----- Original Message -----
From: "Nate Duehr" <nate-Kd9Uk2EBaIJWk0Htik3J/***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 7:17 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Nate Duehr
Post by Rich
I drive with the tailgate down when I use the pickup unloaded. It does save
fuel because up, it can scoop up enough air pressure at 50 mph to cause
significant drag. I have seen some kind of rubber or polymer sheet on some
pickups with big holes in the sheet stretched across the back, and no
tailgate. I assume it is intended to reduce drag but at higher speeds it
seems that perhaps some significant drag may develop to obviate the purpose.
This is exactly what MythBusters disproved.
Having the tailgate up creates a vortex behind the cab to the rear of
the vehicle and actually creates LESS drag when the air flowing over it
of the main airstream interacts with the vortex instead of dragging
along the bed of the vehicle. A "buffer zone" of circular air motion,
so to speak.
The various "remove the tailgate" or "leave it down" products are snake
oil. Those netting-across-the-back products were proven in the show (as
was leaving the tailgate down) to have LOWER gas mileage than leaving it up.
Do your own tests (as they recommended) scientifically if you don't
believe them, but they did a pretty good job of making the tests fair,
and tailgate up won all categories.
Nate
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Jinx
2007-06-28 06:32:15 UTC
Permalink
Post by Rich
I would like to see the smoke test they ran.
I'll dig out that episode and see about some screen grabs for you

(I really really hope the footage does have a smoke test, I'm sure
it did)
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Rich
2007-07-02 06:03:28 UTC
Permalink
Thank you, much. I will appreciate it. I expect to learn something.


----- Original Message -----
From: "Jinx" <joecolquitt-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 2:32 AM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Jinx
Post by Rich
I would like to see the smoke test they ran.
I'll dig out that episode and see about some screen grabs for you
(I really really hope the footage does have a smoke test, I'm sure
it did)
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Jinx
2007-06-28 07:23:41 UTC
Permalink
Post by Rich
I would like to see the smoke test they ran
OK, what they did was use water flow in a tank with a model
pick-up. Oats substituted for smoke. With the tailgate up, the
oats formed a ball behind the cab and other oats flowed over
the top of that ball. With the tailgate down there was no ball

Sorry no smoke, but I knew there was a flow test
Rich
2007-07-02 06:12:43 UTC
Permalink
I don't doubt that the test results were recorded accurately. I do have
some question about the analysis simply because I set out to see if it was
true that TG down saves fuel. My results, of course had to be normalized.
The test was simple. Fill the tank and record the odometer. Fill it again
and record the odometer. Subtract the miles and divide by the number of
gallons to get miles divided by (per) gallons.
Now, my curiosity is piqued and I would like to see what the vortex is
like an what sort of impact that will have on a counter force presented to
the TG and how that counterforce translates into added fuel use. The added
fuel use could easily be converted to counter force applied to the tailgate.


----- Original Message -----
From: "Jinx" <joecolquitt-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 3:23 AM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Jinx
Post by Rich
I would like to see the smoke test they ran
OK, what they did was use water flow in a tank with a model
pick-up. Oats substituted for smoke. With the tailgate up, the
oats formed a ball behind the cab and other oats flowed over
the top of that ball. With the tailgate down there was no ball
Sorry no smoke, but I knew there was a flow test
--------------------------------------------------------------------------------
Post by Jinx
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alan smith
2007-06-28 16:13:56 UTC
Permalink
I've heard the opposite.....that it causes the air pressure to not flow over the truck if the tailgate is down. I've never seen any difference in my truck up or down

Rich <rgrazia1-***@public.gmane.org> wrote: I drive with the tailgate down when I use the pickup unloaded. It does save
fuel because up, it can scoop up enough air pressure at 50 mph to cause
significant drag. I have seen some kind of rubber or polymer sheet on some
pickups with big holes in the sheet stretched across the back, and no
tailgate. I assume it is intended to reduce drag but at higher speeds it
seems that perhaps some significant drag may develop to obviate the purpose.


----- Original Message -----
From: "Dave Tweed"

To: "'Microcontroller discussion list - Public.'"

Sent: Wednesday, June 27, 2007 5:11 PM
Subject: RE: [EE] Simple fuel-saver, so they say
Post by Dave Tweed
Post by Tony Smith
Post by Jinx
Most instructive for saving money were 3 demos
Jeremy Clarkson's London-Edinburgh-London trip in a V8 on one
tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
In the second round of tailgate testing, there was a rather neat
demonstration of E=MV^2, otherwise known as 'going twice as fast
takes four times the effort'.
They ran the test at ~50 MPH (55?), and used 5 gallons or so.
The next run was at 25 MPH, and only used 1.25 gallons. (#s
might off a bit...)
They never commented on it, but it was interesting to see a 'real
life' example.
That has nothing to do with e = 0.5*m*v^2 (instantaneous energy),
and everything to do with the fact that most forms of resistance
(air resistance, rolling resistance, etc.) are proportional to v^2.
This means that the total energy (work) required to travel a given
distance tends to be proportional to v^2, and the power required
(work per unit time) is proportional to v^3.
-- Dave Tweed
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William "Chops" Westfield
2007-06-28 04:27:31 UTC
Permalink
Post by Dave Tweed
Post by Tony Smith
They ran the test at ~50 MPH (55?), and used 5 gallons or so.
The next run was at 25 MPH, and only used 1.25 gallons
That has nothing to do with e = 0.5*m*v^2 (instantaneous energy),
and everything to do with the fact that most forms of resistance
(air resistance, rolling resistance, etc.) are proportional to v^2.
Interestingly, my prius (which features instantaneous and cumulative
milage reports as well as per-trip bargraphs thereof) gets significantly
better milage on mostly highway driving (~52 mpg) than it does on
neighborhood driving (25-35mph, about 40mpg.) I surmise that the
gas usage in the neighborhood is dominated by accelerating. The
semi-mythical 60mpg happens on long stretches of 30-45mph roads and
(surprisingly?) rush-hour freeway traffic (where there's a fair
amount of very slow acceleration to low speeds, and similarly slow
deceleration; ideal for regenerative breaking and electric accel.)

(also interesting is that the air conditioning doesn't seem to
affect milage much, but if you need HEAT, it'll run the gas engine
to create that heat, which has noticeable impact...)

BillW
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Russell McMahon
2007-06-27 15:05:38 UTC
Permalink
The erstwhile tin cones and now "precious metal" ones snake oil fuel
saver on the NZ market has received endorsements by a number of NZ car
clubs and motoring organisations. It doesn't save fuel but these
suckers are prepared to endorse it and help suck more victims in.




Russell
Post by Jinx
Do people become more guilible after buying a car ?
I very nearly did. After being carless for many many years
and ready to get one back on the road, my ears perked up.
Now I'll take a step back and a deep breath before reaching
for the $$
Most instructive for saving money were 3 demos
Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
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Nate Duehr
2007-06-27 23:11:04 UTC
Permalink
Post by Jinx
Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
A moustache? On your face? (???)

Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do. And
illegal in most places to follow closely enough to get the big gains.

Even following a large truck at "reasonable" distances at highway speeds
helps a little bit. A nice long flat road, and a cruise control set to
the speed of the truck ahead of you, and you'll save a few bucks during
the trip... if the truck's not doing 90 MPH! (GRIN)

Nate
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Jinx
2007-06-28 00:57:32 UTC
Permalink
(didn't Top Gear calculate it costs UKP6 a year to haul a
moustache around ?)
A moustache? On your face? (???)
Yes, that kind of moustache. Weight is fuel by their reckoning
and face fungus has weight, therefore.... Similarly get rid of the
crap in the boot, take the roof-rack off if you aren't using it etc

I guess when you add up the cumulative unnecessary tonnage
you cart around during the year it makes sense, even if it does
sound flippant. I'm sure Ferrari don't advocate wearing a diving
belt for better fuel economy ;-)
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Russell McMahon
2007-06-28 05:00:35 UTC
Permalink
Post by Nate Duehr
Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do
Long long ago on a weekly intercity commute of about 70 miles I found
that if I was inside about a motorcycle length behind a large truck
then power requirements were very noticeably reduced. Fun, and much
warmer on cold nights, but hard on the nerves. Not something I did
over any great distances more than a few times as it was far too
dangerous.




Russell
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Rich
2007-06-28 06:06:13 UTC
Permalink
When I was a teen, I would get behind a huge trailer truck right up close
with my little sprite. If the truck was moving about 80 MPH I could get
pulled along for a moment or two. But I had to be what seemed inches away.
I could not sustain the ride. I assumed that the air dynamics were not
right or some wind interfered. It just didn't work out for me.


----- Original Message -----
From: "Russell McMahon" <apptech-wUU9E3n5/m4qAMOr+***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 1:00 AM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Russell McMahon
Post by Nate Duehr
Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do
Long long ago on a weekly intercity commute of about 70 miles I found
that if I was inside about a motorcycle length behind a large truck
then power requirements were very noticeably reduced. Fun, and much
warmer on cold nights, but hard on the nerves. Not something I did
over any great distances more than a few times as it was far too
dangerous.
Russell
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Rich
2007-06-28 05:54:34 UTC
Permalink
If you use a vacuum gage (and they sell some with mileage indicators) you
can consciously practice more efficient driving. I watch the tach and try to
keep it from spiking up quickly. I assume that it will save by not
accelerating rapidly.


----- Original Message -----
From: "Nate Duehr" <nate-Kd9Uk2EBaIJWk0Htik3J/***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 7:11 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Nate Duehr
Post by Jinx
Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
A moustache? On your face? (???)
Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do. And
illegal in most places to follow closely enough to get the big gains.
Even following a large truck at "reasonable" distances at highway speeds
helps a little bit. A nice long flat road, and a cruise control set to
the speed of the truck ahead of you, and you'll save a few bucks during
the trip... if the truck's not doing 90 MPH! (GRIN)
Nate
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Nate Duehr
2007-06-29 02:49:42 UTC
Permalink
Post by Rich
If you use a vacuum gage (and they sell some with mileage
indicators) you
can consciously practice more efficient driving. I watch the tach and try to
keep it from spiking up quickly. I assume that it will save by not
accelerating rapidly.
I swear I read a study somewhere that talked about the desired
behavior is actually to accelerate as hard and quickly as possible to
reach cruise speed quicker.

Heh heh... or was that just my lead foot talking?

--
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nate-Kd9Uk2EBaIJWk0Htik3J/***@public.gmane.org
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Rich
2007-07-02 07:22:51 UTC
Permalink
Some cruise controls do that. But accelerating fast pulls more vacuum. I
think we all talk through our lead foot sometimes :o)


----- Original Message -----
From: "Nate Duehr" <nate-Kd9Uk2EBaIJWk0Htik3J/***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 10:49 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Nate Duehr
Post by Rich
If you use a vacuum gage (and they sell some with mileage
indicators) you
can consciously practice more efficient driving. I watch the tach and try to
keep it from spiking up quickly. I assume that it will save by not
accelerating rapidly.
I swear I read a study somewhere that talked about the desired
behavior is actually to accelerate as hard and quickly as possible to
reach cruise speed quicker.
Heh heh... or was that just my lead foot talking?
--
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Neil Baylis
2007-06-27 13:50:18 UTC
Permalink
Post by Michael Rigby-Jones
It's quite incredible just how many snake oil products exist in the automotive sector. Do people become more guilible after buying a car?
Even worse is the high end audio sector.
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Ling SM
2007-06-27 14:41:17 UTC
Permalink
Post by Neil Baylis
Post by Michael Rigby-Jones
It's quite incredible just how many snake oil products exist in the automotive sector. Do people become more guilible after buying a car?
Even worse is the high end audio sector.
My perception that these "feel good" product cannot and should not have
an easy time was shattered completely after doing a simple survey among
my friends. My gut feel is it maybe representative everywhere. Please
prove that I am wrong from your surveys.

I am resisting to conclude that it is much EASIER to sell what people
want to believe than the real stuff that almost always offer marginal
benefits over cost.

Then again who can deny that the REAL happiness and joy many are
deriding from their super duper audio cable. This, I don't think the
highest end HP Vector Network Analyzer can capture it.

Ling SM
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Nate Duehr
2007-06-27 23:12:56 UTC
Permalink
Post by Ling SM
Then again who can deny that the REAL happiness and joy many are
deriding from their super duper audio cable. This, I don't think the
highest end HP Vector Network Analyzer can capture it.
Some people just want their toys at any price. (Hey, Harley-Davidson's
business plan again! GRIN...)

Nate
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g***@public.gmane.org
2007-06-27 13:09:09 UTC
Permalink
Post by Jinx
I know that
carburettors evolve, but 15% improvement in one go with a
few vanes ?
Carburettor? You're kidding - What's got a carb on it these days?

Jack
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Tony Smith
2007-06-27 14:09:18 UTC
Permalink
Post by Jinx
Post by Jinx
I know that
carburettors evolve, but 15% improvement in one go with a
few vanes ?
Carburettor? You're kidding - What's got a carb on it these days?
Jack
My bike has four of them. I'm not quite sure why someone decided to put
four carbs on a four cylinder 600cc motor, but anyway. At least the 250
only has one. (And no fuel filter as standard, you be surprised at the tiny
size a bit of grit needs to be to jam the float)

Not a good example, btw. Bikes tend to be conservative in their design.
Anything 'odd' rarely lasts a model or two. Hey, it works, people buy them,
why change? (I think I just described Harley Davidsons business plan.)

Tony
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David VanHorn
2007-06-27 16:53:45 UTC
Permalink
Post by g***@public.gmane.org
Carburettor? You're kidding - What's got a carb on it these days?
Lawnmowers?
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Carl Denk
2007-06-27 20:30:21 UTC
Permalink
Sears 20" lawnmower with Briggs engine, 27 Hp. Kohler Engine available
as injected or carb. I use the Carb. for standby generator since it had
a gasoline cutoff solenoid that I could use when running other fuels.
Didn't want to get into the issues related to the cutoff with injection,
not knowing the electronics embedded.
Post by David VanHorn
Post by g***@public.gmane.org
Carburettor? You're kidding - What's got a carb on it these days?
Lawnmowers?
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g***@public.gmane.org
2007-06-27 20:49:06 UTC
Permalink
Post by Carl Denk
27 Hp. Kohler Engine available
as injected or carb. I use the Carb. for standby generator since it had
a gasoline cutoff solenoid that I could use when running other fuels.
Sounds interesting -Care to elaborate?

Jack
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Carl Denk
2007-06-27 21:29:05 UTC
Permalink
The 12.5KW generator is cog belt drive from engine. The engine runs
natural gas (from our own well), gasoline (175 gallon tank for vehicles
10' away)(automatic transfer to generator's 16 gallon tank), or propane
and will seamlessly
switch between any of the fuels depending what is available. A Tri-PLC
T100MD888+ manages the whole thing. The PLC programs in ladder logic
with Basic routines embedded in the rungs (circuits). A PIC 18F1320 at
the gas well monitors well head and regulated gas pressures and
enclosure temperature. The PIC comunicates with the PLC via fiber optic
thats converted to RS-485 in the house.

We drilled the gas well 30 years ago for $8K USD, and it is 1000' deep.
The well serves only the house, and in very cold windy weather can be
temporarily depleted, but an hour rest and it's good for a half a day again.

I'm looking for a way to comunicate 2 ways with the PLC via. phone,
probably tones to the PLC and voice out of the house. This would
probably be on the RS-485, but could go RS-232.
Post by g***@public.gmane.org
Post by Carl Denk
27 Hp. Kohler Engine available
as injected or carb. I use the Carb. for standby generator since it had
a gasoline cutoff solenoid that I could use when running other fuels.
Sounds interesting -Care to elaborate?
Jack
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Nate Duehr
2007-06-27 23:19:56 UTC
Permalink
Post by Carl Denk
We drilled the gas well 30 years ago for $8K USD, and it is 1000' deep.
The well serves only the house, and in very cold windy weather can be
temporarily depleted, but an hour rest and it's good for a half a day again.
How did you get the mineral rights?

Out here in the westnern U.S., you might own the land on top but not the
minerals, gas, oil, or whatever below.

Was it difficult? Or did you just tap the gas and not care? Or did you
have a property that also included underground mineral rights?

Just curious -- if you had to go through that process, what did it cost
for that part of the well.

Nate
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Carl Denk
2007-06-28 01:27:45 UTC
Permalink
That's the same as Ohio, surface and mineral rights are 2 different items.

We made mineral rights part of the offer to purchase the 6.5 acres.
Turns out the farmer (land was winter wheat harvested day before we dug
basement) had sold mineral rights to the parts of the 500 or so acres he
owned checkerboard style (he wasn't particularly fond of the purchasing
salesman), and our particular parcel was one that had not been sold.
Mineral rights didn't cost anything, just came along with the deal. The
$8K was to the driller.

As we were building house, hired a well driller (cable tool rig) to
drill for water. 3 holes were dry, he got down about 80 feet and after
looking, feeling, and sniffing mud coming up, he said there was no
useable water down there. On the 3rd hole we started talking about gas,
an he pointe out around the horizon, a half dozen houses that had their
own gas well. We came to an agreement, the driller got the necessary
State of Ohio drilling permits (the operation was regularly inspected),
ordered casing, put a loner cable on the rig and started drilling. The
hole has 120 feet of 8" casing to case off any fresh water if any,
another 60 foot of 6" casing to case off the salt water (artesion (sp)
to within 20' of surface). Top of 8" casing has a blind bolted flange,
1.25" pipe coupling welded to side, which then takes well head pressure
(0 to 50 PSI.) to regulator down to 6" H20 pressure and on to house. The
natural gas has a dew point of water vapor around freezing. The well
head and all piping exposed to the weather must be heated in winter, an
enclosure around the well, regulator (and the PIC), heat trace tape
other spots.
Post by Nate Duehr
Post by Carl Denk
We drilled the gas well 30 years ago for $8K USD, and it is 1000' deep.
The well serves only the house, and in very cold windy weather can be
temporarily depleted, but an hour rest and it's good for a half a day again.
How did you get the mineral rights?
Out here in the westnern U.S., you might own the land on top but not the
minerals, gas, oil, or whatever below.
Was it difficult? Or did you just tap the gas and not care? Or did you
have a property that also included underground mineral rights?
Just curious -- if you had to go through that process, what did it cost
for that part of the well.
Nate
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Jinx
2007-06-28 03:49:25 UTC
Permalink
Fancy that (or this). Read the Repco catalogue again

http://www.repco.co.nz/services/cat/1.html

honestly looking for other products (new battery, seat covers),
and found that the Magnetronic piece of crap is actually a
Magnatronic piece of crap

http://www.magnatronicpr.com/FAQ.html

I will have a word with Repco (at least) about getting said crap
off their shelves
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Brent Brown
2007-06-28 05:12:31 UTC
Permalink
Post by Jinx
Fancy that (or this). Read the Repco catalogue again
http://www.repco.co.nz/services/cat/1.html
honestly looking for other products (new battery, seat covers),
and found that the Magnetronic piece of crap is actually a
Magnatronic piece of crap
http://www.magnatronicpr.com/FAQ.html
I will have a word with Repco (at least) about getting said crap
off their shelves
Following your lead I just sent them a message through their website. Now what
about that magnetic woolen underlay also advertised on TV...?
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Jinx
2007-06-28 05:33:58 UTC
Permalink
Post by Brent Brown
Post by Jinx
I will have a word with Repco (at least) about getting said crap
off their shelves
Following your lead I just sent them a message through their
website
I've tried to speak to someone in authority at Repco but, being
advertising types, they'd already buggered off home at 4pm

Interestingly, as I passed through their phone system and explained
my complaint, all three people agreed. I wish I'd recorded them
dissing on their own product. mmm mmm

When I first called their 0800 number I got put through to a store
without realising (thought I was talking to head office), and
proceeded to give a till jockey a hard time, for which I apologised

He wanted to debate the issue, and to his credit was the only one
prepared to duke it out on behalf of the product. I'd really have
expected the reverse

He claimed that "he'd heard" of people it worked for but couldn't
substantiate that. I counter-claimed that some people say they have
invented and patented a perpetual motion machine, and asked
would he buy one for $169 ? No, he said

1-nil

My experience is that people who claim these benefits have no
hard data to support that, but those who claim they have no
benefits DO have the numbers

Supposed to be receiving a call from up top tomorrow
Post by Brent Brown
Now what about that magnetic woolen underlay also advertised
on TV...?
aaaaargh !!!!!
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Russell McMahon
2007-06-28 07:03:17 UTC
Permalink
Post by Jinx
Post by Brent Brown
Now what about that magnetic woolen underlay also advertised
on TV...?
aaaaargh !!!!!
That item particularly and that sort of thing in general annoy me
greatly.

They play on the suffering of people to sell an utterly shonky profit
at exorbitant * prices.

The placebo effect, random distribution and happenstance, and an N day
money back man that they can claim thousands of satisfied customers
and thereby continue to sell their ripoff extortionate ripoff products
to thousands more.

In the case of the "biomag" "magnetic fleece underlay" - a fleece
mattress cover with magnets imbedded, the fleece part probably does
some good for some people and makes the magnet effect or lack thereof
hard to ascertain or demonstrate. It would not be at all hard to do
double blind controlled trials if they were really interested in doing
so - but that would most certainly kill the goose that is laying their
golden eggs for them.

Maybe there's a market niche for an oxygen free copper magnetic wool
precious metal cones turbulizer? A real fleece product!

That is, fwiw, by no means the biggest con going in NZ at present. By
far the biggest ripoff that I am aware of is "retirement villages". So
well done that the vast majority of people are not aware that these
are legalised licences to ripoff people on a scale that is almost
impossible to match anywhere else. Compared to this the occasional
petty conman who charges an old person $5000, or even $15000 to paint
their fence is in a completely different (and minor) league. I suspect
that even Jinx will not initially make sense of this assertion.




Russell


* Not that there is a price that isn't exorbitant for such products.
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Jinx
2007-06-28 09:14:12 UTC
Permalink
Post by Russell McMahon
Post by Jinx
Post by Brent Brown
Now what about that magnetic woolen underlay also advertised
on TV...?
aaaaargh !!!!!
That item particularly and that sort of thing in general annoy me
greatly.
I'v thought about those before. Never been able to find any data
to support their claim. But note that are quite careful with those
claims. The advertising is very fuzzy about what benefits you can
expect. "may help" type of statements etc, and that's what stopped
me making a formal complaint. I think if you pursued it you might
dent their reputation, but it's not so clear-cut (to me anyway) as
advertising a product with "Guaranteed fuel savings" in big print
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Tony Smith
2007-06-28 13:26:31 UTC
Permalink
Post by Jinx
Supposed to be receiving a call from up top tomorrow
Post by Brent Brown
Now what about that magnetic woolen underlay also
advertised on TV...?
aaaaargh !!!!!
Today I encountered a woman who refused to keep stuff in the office fridge.
The reason was that it was covered magnets. Now this just isn't logical, as
everyone knows magnets are good for you (except electromagnets, which emit
electricity, radiation and bad vibes.) Her home fridge had none, which is
why she was so healthy & happy. I guess the milk didn't get polarised or
something.

You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)

Tony
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David VanHorn
2007-06-28 14:03:49 UTC
Permalink
Post by Tony Smith
You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)
Did you tell her she's living on an enormously powerful magnet whose
field reaches out thousands of miles into space?
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Jinx
2007-06-28 14:12:46 UTC
Permalink
Post by David VanHorn
Did you tell her she's living on an enormously powerful magnet
whose field reaches out thousands of miles into space ?
I'm so fed-up with these wretched people who select facts to
suit their bias/prejudice/hippy leanings. And they won't be told
will they, because it unsettles them and they take it personally

My all-time favourite description of them is from the B***s**t
series. Penn Jillette's, and I apologise profusely beforehand, but
he does it just so well - "Then there's THIS asshole"
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Alan B. Pearce
2007-06-28 14:54:07 UTC
Permalink
Post by David VanHorn
Post by Tony Smith
You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)
Did you tell her she's living on an enormously powerful magnet
whose field reaches out thousands of miles into space?
Hmm, went to a talk this morning here at work where details were presented
about this scheme that is afoot to do a "Star Trek" style shield from solar
radiation for planetary travellers.

Apparently they reckon only about 50nT is needed to shield you from the
plasma ejections from the sun ...
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Nate Duehr
2007-06-29 02:44:31 UTC
Permalink
Post by David VanHorn
Post by Tony Smith
You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)
Did you tell her she's living on an enormously powerful magnet whose
field reaches out thousands of miles into space?
Sounds like the next Christmas Secret Santa party you need to get her
a real magnetic compass for a present.

Then ask her to hold it up to the earpiece of her desk telephone.

That oughta freak her out beyond belief... :-)

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Russell McMahon
2007-06-28 14:28:58 UTC
Permalink
Post by Tony Smith
You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)
But, the door seal probably has a crystal lining over the magnets.


Russell
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Peter P.
2007-06-30 20:38:24 UTC
Permalink
Post by Russell McMahon
Post by Tony Smith
showed her how a fridge door seal works... :)
But, the door seal probably has a crystal lining over the magnets.
Don't the magnets and the crystals have FCC IDs ? The magnets are radiating an
intended electromagnetic field with a frequency of at least 1/86400 Hz [1] and
the crystals must be receiving and annihilating this field, thus being
intentional receivers.

Peter P.

[1] There are 86400 seconds in a standard day
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David VanHorn
2007-06-30 21:34:45 UTC
Permalink
Post by Peter P.
Don't the magnets and the crystals have FCC IDs ? The magnets are radiating an
intended electromagnetic field with a frequency of at least 1/86400 Hz [1] and
the crystals must be receiving and annihilating this field, thus being
intentional receivers.
Devices with operating frequencies below 9 kHz are exempt.
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Cedric Chang
2007-06-28 05:43:27 UTC
Permalink
I admire you guys for sending messages.
Cedric
Post by Brent Brown
Post by Jinx
Fancy that (or this). Read the Repco catalogue again
http://www.repco.co.nz/services/cat/1.html
honestly looking for other products (new battery, seat covers),
and found that the Magnetronic piece of crap is actually a
Magnatronic piece of crap
http://www.magnatronicpr.com/FAQ.html
I will have a word with Repco (at least) about getting said crap
off their shelves
Following your lead I just sent them a message through their
website. Now what
about that magnetic woolen underlay also advertised on TV...?
--
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16 English Street, St Andrews,
Hamilton 3200, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell: 027 433 4069
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Jinx
2007-06-28 22:52:36 UTC
Permalink
Post by Cedric Chang
I admire you guys for sending messages.
Cedric
Thanks Cedric. I really do want garbage like this off the market,
partly because, like most people, I'm basically honest, and very
honest when it comes to claims about my own products. To
claim and guarantee that magnets save fuel is very dishonest

Repco are a big chain, by Australasian standards, and they
should be more careful. For a company that says "Cars are our
life too" you'd think they should have taken some notice of fuel-
saver debunkings, specifically in NZ wrt to magnets, the AA,
Consumer Magazine, and even the NZ Government

http://www.aardvark.co.nz/daily/2000/0822.shtml

The shop assistant I spoke to yesterday would have done his
job and sold me one. I don't know whether he actually believed
what he was saying. And maybe he doesn't today after the ear-
ache I gave him ;-)) !! Is selling things his whole job ? I don't
think so. But he can't question the company products either (my
niece is a "secret shopper" and might report people like him)

That a product is advertised as "money-back, no questions" is
no defense against selling it in the first place. Money-back is
covered by law anyway. What irks me is that some customers
will not return it, for various reasons, but that doesn't mean
they're satisfied. It's just too much bother, or whatever. More
fool them, but that encourages the scammers and probably, by
the dodgy logic that goes with their dodgy science, validates
the product further

We shall see what the day delivers
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Edward King
2007-06-28 15:25:49 UTC
Permalink
Hi!

Ive just finished a contract during which I did some work using a GSM module
that does everythign you're wanting. Would you like me to forward the
details on to you or have you an alternative in mind?

Edward


----- Original Message -----
From: "Carl Denk" <cdenk-zZbu3ta402WsTnJN9+***@public.gmane.org>
To: <goflo-***@public.gmane.org>
Cc: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 12:29 AM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Carl Denk
The 12.5KW generator is cog belt drive from engine. The engine runs
natural gas (from our own well), gasoline (175 gallon tank for vehicles
10' away)(automatic transfer to generator's 16 gallon tank), or propane
and will seamlessly
switch between any of the fuels depending what is available. A Tri-PLC
T100MD888+ manages the whole thing. The PLC programs in ladder logic
with Basic routines embedded in the rungs (circuits). A PIC 18F1320 at
the gas well monitors well head and regulated gas pressures and
enclosure temperature. The PIC comunicates with the PLC via fiber optic
thats converted to RS-485 in the house.
We drilled the gas well 30 years ago for $8K USD, and it is 1000' deep.
The well serves only the house, and in very cold windy weather can be
temporarily depleted, but an hour rest and it's good for a half a day again.
I'm looking for a way to comunicate 2 ways with the PLC via. phone,
probably tones to the PLC and voice out of the house. This would
probably be on the RS-485, but could go RS-232.
Post by g***@public.gmane.org
Post by Carl Denk
27 Hp. Kohler Engine available
as injected or carb. I use the Carb. for standby generator since it had
a gasoline cutoff solenoid that I could use when running other fuels.
Sounds interesting -Care to elaborate?
Jack
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g***@public.gmane.org
2007-06-28 01:35:53 UTC
Permalink
Knew there was a reason I kept my flak jacket....

Not rocket science, guys - You want MPGs, slow down.
Had my nose rubbed in it driving a VW Bus for 30 years;
@35 mph 24 mpg, 55 mph 16 mpg. It'd manage 70+ mph
on the flat, but the fuel consumption was intolerable, and
a cross wind would put you in the klong, so did'nt spend
enough time in that part of the envelope to get real numbers.

Jack
Post by Nate Duehr
Post by Jinx
Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
A moustache? On your face? (???)
Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do. And
illegal in most places to follow closely enough to get the big gains.
Even following a large truck at "reasonable" distances at highway speeds
helps a little bit. A nice long flat road, and a cruise control set to
the speed of the truck ahead of you, and you'll save a few bucks during
the trip... if the truck's not doing 90 MPH! (GRIN)
Nate
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Rich
2007-06-28 05:34:57 UTC
Permalink
It is interesting that many people believe that the fuel actually explodes
in the cylinder and drives the piston against the crankshaft. That is
hardly the case. The IC engine is a heat engine just as the steam engine is
a heat engine. The mileage depends on the efficiency of the conversion of
fuel into heat. The fuel-air mixture burns: it does not explode. When the
cylinder comes up it compresses the air creating an oxygen rich environment
for the fuel mixture. The spark causes the fuel to burn and the heat from
the oxidation of the fuel causes the fluid molecules inside the cylinder to
expand rapidly and equally in all directions. The force acting on the
piston head from the expanding molecules is what moves the crank shaft.
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency. But the optimum fuel-air mixture for the most complete
combustion is not used (BUT in MHO it could be). The mixture is always on
the rich side to guarantee predictable and repeatable ignition without any
dead cycles. The rich mixture is another inefficiency because it results in
less than complete combustion. There are some other kinetic factors like
the inertial forces and migration of the mixture through the manifold, which
is why polished ports and manifolds yield more power.
Increasing the compression would create a richer oxygen environment to
produce a hotter burn (more heat) which is the whole objective of the IC
engine. But too much oxygen would move the process from burn to explode
which would damage the engine. There is the real limit on mileage and
efficiency: How much heat you can get from the burn of the fuel without
exploding it. In diesel engines the compression ratio is much higher and it
is so oxygen rich that a spark is not required to initiate the burn. But
here, again, the efficiency limit is imposed by the rate of oxidation; too
fast and BOOM, you wrecked your engine. The reason diesel can tolerate
higher oxygen ratios is because there is less BTU per unit volume than for
gasoline, of whatever octane.
So to get more mileage you need to figure out how to get more heat per
unit fuel, a more complete burn and keep on the safe side of explosion.
Now here is an interesting point. Some people talk about alternative
energy on one side of the page and better efficiency on the other side. So
they came up with ethanol. Ethanol has less BTU per unit volume than
Gasoline. To save energy they advocate mixing ethanol with the gasoline and
at some pumps it is already premixed. Question! How is mixing something
with less energy with something with more energy going to result in
increased efficiency, or better mileage, and so on. The heat produced by
the burn will actually decrease, resulting on lower power. The problem of
repeatable ignition cycles requiring a richer mixture remains. Is it an
oxymoron? Or is it simply a moron idea? I am baffled by it.


----- Original Message -----
From: <goflo-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Wednesday, June 27, 2007 9:35 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by g***@public.gmane.org
Knew there was a reason I kept my flak jacket....
Not rocket science, guys - You want MPGs, slow down.
Had my nose rubbed in it driving a VW Bus for 30 years;
@35 mph 24 mpg, 55 mph 16 mpg. It'd manage 70+ mph
on the flat, but the fuel consumption was intolerable, and
a cross wind would put you in the klong, so did'nt spend
enough time in that part of the envelope to get real numbers.
Jack
Post by Nate Duehr
Post by Jinx
Jeremy Clarkson's London-Edinburgh-London trip in a V8
on one tank of diesel and similar tests on the track by both
Mythbusters and a NZ motoring program. You can save
substantially by driving conservatively, including reducing
drag (windows and tailgate up) and weight (didn't Top Gear
calculate it costs UKP6 a year to haul a moustache around ?)
A moustache? On your face? (???)
Mythbusters also proved that tailgating large trucks helps a lot, but
it's a pretty horrible way to die if you don't stop when they do. And
illegal in most places to follow closely enough to get the big gains.
Even following a large truck at "reasonable" distances at highway speeds
helps a little bit. A nice long flat road, and a cruise control set to
the speed of the truck ahead of you, and you'll save a few bucks during
the trip... if the truck's not doing 90 MPH! (GRIN)
Nate
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Cedric Chang
2007-06-28 07:06:17 UTC
Permalink
Post by Rich
It is interesting that many people believe that the fuel actually explodes
in the cylinder and drives the piston against the crankshaft. That is
hardly the case. The IC engine is a heat engine just as the steam engine is
a heat engine. The mileage depends on the efficiency of the
conversion of
fuel into heat. The fuel-air mixture burns: it does not explode.
When the
cylinder comes up it compresses the air creating an oxygen rich environment
for the fuel mixture. The spark causes the fuel to burn and the heat from
the oxidation of the fuel causes the fluid molecules inside the cylinder to
expand rapidly and equally in all directions. The force acting on the
piston head from the expanding molecules is what moves the crank shaft.
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency. But the optimum fuel-air mixture for the most complete
combustion is not used (BUT in MHO it could be). The mixture is always on
the rich side to guarantee predictable and repeatable ignition
without any
dead cycles. The rich mixture is another inefficiency because it results in
less than complete combustion. There are some other kinetic
factors like
the inertial forces and migration of the mixture through the
manifold, which
is why polished ports and manifolds yield more power.
Increasing the compression would create a richer oxygen
environment to
produce a hotter burn (more heat) which is the whole objective of the IC
engine. But too much oxygen would move the process from burn to explode
which would damage the engine. There is the real limit on mileage and
efficiency: How much heat you can get from the burn of the fuel without
exploding it. In diesel engines the compression ratio is much
higher and it
is so oxygen rich that a spark is not required to initiate the
burn. But
here, again, the efficiency limit is imposed by the rate of
oxidation; too
fast and BOOM, you wrecked your engine. The reason diesel can
tolerate
higher oxygen ratios is because there is less BTU per unit volume than for
gasoline, of whatever octane.
So to get more mileage you need to figure out how to get more heat per
unit fuel, a more complete burn and keep on the safe side of
explosion.
Now here is an interesting point. Some people talk about
alternative
energy on one side of the page and better efficiency on the other side. So
they came up with ethanol. Ethanol has less BTU per unit volume than
Gasoline. To save energy they advocate mixing ethanol with the gasoline and
at some pumps it is already premixed. Question! How is mixing something
with less energy with something with more energy going to result in
increased efficiency, or better mileage, and so on. The heat
produced by
the burn will actually decrease, resulting on lower power. The problem of
repeatable ignition cycles requiring a richer mixture remains. Is it an
oxymoron? Or is it simply a moron idea? I am baffled by it.
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?

Here are some excerpts from the internet:
1) Piston failure in two-stroke engines.(SHOP TALK)
In my opinion, overheating is the most common cause of engine
failure. ... The carburetor is adjusted too lean. Such failures are
common with operators who ...
2) Rough engine. Misfire. Vibration in Lycoming or Continental ...
This causes overheating of the points and erosion of point
surfaces. ... Excessive lean mixtures at low engine speed will result
in rough and erratic idle ...
3) Engine Seizures
If the high speed circuit is lean enough to cause piston seizure, it
will also tend to ... If an engine is operating on the ragged edge of
overheating, ...

Cedric
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Peter P.
2007-06-28 12:46:26 UTC
Permalink
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
In a 10,000 RPM 2-stroke engine total fuel burn occurs in less than 2 msec and
it is not called an explosion. The spark timing must be more accurate than a
tenth of that to avoid problems at high power. 200 usec does not sound like much
for amicro but the rotation timing sensor must be at least twice as accurate
over temperature, voltage and age. A normal car engine that revs up to about
5000 should finish burning anything in 4 msec or less, or there will be flame
out the exhaust. An explosion occurs when the mixture goes off faster than the
speed of sound in it (see deflagration and detonation on Wikipedia). At the
speed of sound at STP in a 1 inch bore engine the flame needs 350 usec to reach
the cylinder wall from the central spark plug. So if the engine must burn in
under 2 msec but 350 usec is the limit for detonation (actually it is more
complicated than that but this is just a beer coaster explanation) the 'normal'
operation is *extremely* close to detonation regime (known as knocking), and
remember that the transition is exponential (flame speed grows exponentially as
conditions near detonation conditions).

Peter P.
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Russell McMahon
2007-06-28 14:27:46 UTC
Permalink
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was
"exploding" ?
Even fuel in liquid rocket motors does *NOT* explode - at least not
intentionally.
There are experimental rocket engines known as PDEs (Pulse Detonation
Engines) where the fuel is injected and compressed and then literally
detonated. The noise is immense and the forces are substantially
higher than in a normal engine. In a normal rocket motor you know when
detonation has occurred because the engine is scattered widely in many
pieces :-).




Russell
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William Couture
2007-06-28 14:49:59 UTC
Permalink
Post by Russell McMahon
Even fuel in liquid rocket motors does *NOT* explode - at least not
intentionally.
There are experimental rocket engines known as PDEs (Pulse Detonation
Engines) where the fuel is injected and compressed and then literally
detonated. The noise is immense and the forces are substantially
higher than in a normal engine. In a normal rocket motor you know when
detonation has occurred because the engine is scattered widely in many
pieces :-).
Even better when you use nuclear bombs as the propulsion.

http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion

Bill
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William "Chops" Westfield
2007-06-28 19:52:52 UTC
Permalink
Post by Peter P.
An explosion occurs when the mixture goes off faster than the
speed of sound in it (see deflagration and detonation on Wikipedia).
Right. A "detonation" is the supersonic reaction, and a "deflagration"
is subsonic. But "explosion" is an ambiguous non-technical term
generally used by the US BATFE to restrict access to "explosives"
that it doesn't like people to have. See also "high explosive"
(detonates; eg dynamite) vs "low explosive" (doesn't detonate, eg
black powder.)

BillW
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Peter P.
2007-06-30 18:02:41 UTC
Permalink
Post by William "Chops" Westfield
Right. A "detonation" is the supersonic reaction, and a "deflagration"
is subsonic.
Funny that deflagration seems to have the root from 'Phlogiston'. I guess that
the word deflagration suggests that the Phlogiston is being let out. Or, iow,
smoke let-out in 17th (?) century PhDspeak ? See more here:

http://en.wikipedia.org/wiki/Phlogiston_theory

Peter P.
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Rich
2007-07-02 05:35:17 UTC
Permalink
Which is why I pointed out that the richer mixture is necessary to run the
engine predictably. If the mixture is too lean or even if the mixture is
optimal for complete combustion, the engine performance will suffer. I did
not suggest that the mixture be made more lean, I explained why it could not
be so.


----- Original Message -----
From: "Cedric Chang" <cc-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 3:06 AM
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Cedric Chang
Post by Rich
It is interesting that many people believe that the fuel actually explodes
in the cylinder and drives the piston against the crankshaft. That is
hardly the case. The IC engine is a heat engine just as the steam engine is
a heat engine. The mileage depends on the efficiency of the
conversion of
fuel into heat. The fuel-air mixture burns: it does not explode.
When the
cylinder comes up it compresses the air creating an oxygen rich environment
for the fuel mixture. The spark causes the fuel to burn and the heat from
the oxidation of the fuel causes the fluid molecules inside the cylinder to
expand rapidly and equally in all directions. The force acting on the
piston head from the expanding molecules is what moves the crank shaft.
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency. But the optimum fuel-air mixture for the most complete
combustion is not used (BUT in MHO it could be). The mixture is always on
the rich side to guarantee predictable and repeatable ignition without any
dead cycles. The rich mixture is another inefficiency because it results in
less than complete combustion. There are some other kinetic
factors like
the inertial forces and migration of the mixture through the
manifold, which
is why polished ports and manifolds yield more power.
Increasing the compression would create a richer oxygen
environment to
produce a hotter burn (more heat) which is the whole objective of the IC
engine. But too much oxygen would move the process from burn to explode
which would damage the engine. There is the real limit on mileage and
efficiency: How much heat you can get from the burn of the fuel without
exploding it. In diesel engines the compression ratio is much higher and it
is so oxygen rich that a spark is not required to initiate the burn. But
here, again, the efficiency limit is imposed by the rate of
oxidation; too
fast and BOOM, you wrecked your engine. The reason diesel can tolerate
higher oxygen ratios is because there is less BTU per unit volume than for
gasoline, of whatever octane.
So to get more mileage you need to figure out how to get more heat per
unit fuel, a more complete burn and keep on the safe side of
explosion.
Now here is an interesting point. Some people talk about
alternative
energy on one side of the page and better efficiency on the other side. So
they came up with ethanol. Ethanol has less BTU per unit volume than
Gasoline. To save energy they advocate mixing ethanol with the gasoline and
at some pumps it is already premixed. Question! How is mixing something
with less energy with something with more energy going to result in
increased efficiency, or better mileage, and so on. The heat
produced by
the burn will actually decrease, resulting on lower power. The problem of
repeatable ignition cycles requiring a richer mixture remains. Is it an
oxymoron? Or is it simply a moron idea? I am baffled by it.
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
1) Piston failure in two-stroke engines.(SHOP TALK)
In my opinion, overheating is the most common cause of engine
failure. ... The carburetor is adjusted too lean. Such failures are
common with operators who ...
2) Rough engine. Misfire. Vibration in Lycoming or Continental ...
This causes overheating of the points and erosion of point
surfaces. ... Excessive lean mixtures at low engine speed will result
in rough and erratic idle ...
3) Engine Seizures
If the high speed circuit is lean enough to cause piston seizure, it
will also tend to ... If an engine is operating on the ragged edge of
overheating, ...
Cedric
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Michael Rigby-Jones
2007-06-28 10:42:19 UTC
Permalink
-----Original Message-----
On Behalf Of Rich
Sent: 28 June 2007 06:35
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Simple fuel-saver, so they say
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency.
I'm not sure this can be true. The very fact that the cylinder and cylinder head are present is what creates the pressure in the first place. Exterting pressure on a static body performs no work. What does reduce efficiency is the cylinder, head and piston absorbing heat from the burning fuel/air mixture, which is why ceramic coatings have been developed to try to reduce this (for piston and head at least).
In diesel engines the compression ratio is much
higher and it
is so oxygen rich that a spark is not required to initiate the
burn.
The reason it does not need a spark is because the heat created during compression is used instead. This heat would also readily ignite a stoichiometric gasoline/air mixture, but the resulting burn would not be controlled, e.g. detonation.
The reason diesel can
tolerate
higher oxygen ratios is because there is less BTU per unit
volume than for
gasoline, of whatever octane.
Diesel actually has a higher energy content than gasoline. Also note that octane rating is not an indicator of energy content of gasoline! In fact very often the high octane fuels will have slightly lower energy density, because the additives required to increase the octane rating displace some fuel (e.g. what used to be tetra-ethyl lead many years ago). High octane simply means that the fuel has improved resistance to detonation, so a higher compression ratio can be used to extract more energy from the fuel.

The reason that very weak (i.e. excess oxygen) mixtures can be ignited in a diesel is because they do not rely on a small spark located at one point in the combustion chamber, instead the fuel is injected into the compressed and heated air and starts burning immediately. In a gasoline engine, the mixture has to have enough fuel for the spark to initiate combustion. This is why stratified charge engines have been developed, this creates a small fuel rich mixture around the spark plug, surrounded by a larger volume of weak mixture. Once the rich mixture is ignited, the flame front will happily propagate through the weaker regions. The GDI engines that e.g. Mitsubishi have developed rely on this.

Note that the actual mixture ratio in a diesel varies considerably over the engines operating range because it not throttled, i.e. the volumetric efficiency is more or less constant, only the amount of fuel injected varies.

Regards

Mike

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Rich
2007-07-02 07:19:46 UTC
Permalink
Yes, the heat plays an important role but without the increased oxygen the
heat developed by the combustion would be less, if combustion could still be
sustained a lower oxygen levels.

----- Original Message -----
From: "Michael Rigby-Jones" <Michael.Rigby-Jones-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 6:42 AM
Subject: RE: [EE] Simple fuel-saver, so they say
Post by Michael Rigby-Jones
-----Original Message-----
On Behalf Of Rich
Sent: 28 June 2007 06:35
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Simple fuel-saver, so they say
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency.
I'm not sure this can be true. The very fact that the cylinder and
cylinder head are present is what creates the pressure in the first place.
Exterting pressure on a static body performs no work. What does reduce
efficiency is the cylinder, head and piston absorbing heat from the
burning fuel/air mixture, which is why ceramic coatings have been
developed to try to reduce this (for piston and head at least).
In diesel engines the compression ratio is much
higher and it
is so oxygen rich that a spark is not required to initiate the
burn.
The reason it does not need a spark is because the heat created during
compression is used instead. This heat would also readily ignite a
stoichiometric gasoline/air mixture, but the resulting burn would not be
controlled, e.g. detonation.
The reason diesel can
tolerate
higher oxygen ratios is because there is less BTU per unit
volume than for
gasoline, of whatever octane.
Diesel actually has a higher energy content than gasoline. Also note that
octane rating is not an indicator of energy content of gasoline! In fact
very often the high octane fuels will have slightly lower energy density,
because the additives required to increase the octane rating displace some
fuel (e.g. what used to be tetra-ethyl lead many years ago). High octane
simply means that the fuel has improved resistance to detonation, so a
higher compression ratio can be used to extract more energy from the fuel.
The reason that very weak (i.e. excess oxygen) mixtures can be ignited in
a diesel is because they do not rely on a small spark located at one point
in the combustion chamber, instead the fuel is injected into the
compressed and heated air and starts burning immediately. In a gasoline
engine, the mixture has to have enough fuel for the spark to initiate
combustion. This is why stratified charge engines have been developed,
this creates a small fuel rich mixture around the spark plug, surrounded
by a larger volume of weak mixture. Once the rich mixture is ignited, the
flame front will happily propagate through the weaker regions. The GDI
engines that e.g. Mitsubishi have developed rely on this.
Note that the actual mixture ratio in a diesel varies considerably over
the engines operating range because it not throttled, i.e. the volumetric
efficiency is more or less constant, only the amount of fuel injected
varies.
Regards
Mike
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Rich
2007-07-02 07:35:35 UTC
Permalink
Yes, that is true. The heat absorption of the engine components do
contribute to a loss of efficiency. However, the forces acting normal to
the direction of displacement do not add directly to the piston
displacement. The argument for the random collision is inconsequential
because the forces are not significantly redirected.
The molecular expansion would have to be uniformly directed along the
axis of travel of the piston for "all" of the forces to be utilized. But
that is impossible.
There is much more to be said regarding the molecular dynamics but I
believe it would go to a level of discussion beyond what I intended here,
although I would not object to some off-list discussion.


----- Original Message -----
From: "Michael Rigby-Jones" <Michael.Rigby-Jones-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 6:42 AM
Subject: RE: [EE] Simple fuel-saver, so they say
Post by Michael Rigby-Jones
-----Original Message-----
On Behalf Of Rich
Sent: 28 June 2007 06:35
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Simple fuel-saver, so they say
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency.
I'm not sure this can be true. The very fact that the cylinder and
cylinder head are present is what creates the pressure in the first place.
Exterting pressure on a static body performs no work. What does reduce
efficiency is the cylinder, head and piston absorbing heat from the
burning fuel/air mixture, which is why ceramic coatings have been
developed to try to reduce this (for piston and head at least).
In diesel engines the compression ratio is much
higher and it
is so oxygen rich that a spark is not required to initiate the
burn.
The reason it does not need a spark is because the heat created during
compression is used instead. This heat would also readily ignite a
stoichiometric gasoline/air mixture, but the resulting burn would not be
controlled, e.g. detonation.
The reason diesel can
tolerate
higher oxygen ratios is because there is less BTU per unit
volume than for
gasoline, of whatever octane.
Diesel actually has a higher energy content than gasoline. Also note that
octane rating is not an indicator of energy content of gasoline! In fact
very often the high octane fuels will have slightly lower energy density,
because the additives required to increase the octane rating displace some
fuel (e.g. what used to be tetra-ethyl lead many years ago). High octane
simply means that the fuel has improved resistance to detonation, so a
higher compression ratio can be used to extract more energy from the fuel.
The reason that very weak (i.e. excess oxygen) mixtures can be ignited in
a diesel is because they do not rely on a small spark located at one point
in the combustion chamber, instead the fuel is injected into the
compressed and heated air and starts burning immediately. In a gasoline
engine, the mixture has to have enough fuel for the spark to initiate
combustion. This is why stratified charge engines have been developed,
this creates a small fuel rich mixture around the spark plug, surrounded
by a larger volume of weak mixture. Once the rich mixture is ignited, the
flame front will happily propagate through the weaker regions. The GDI
engines that e.g. Mitsubishi have developed rely on this.
Note that the actual mixture ratio in a diesel varies considerably over
the engines operating range because it not throttled, i.e. the volumetric
efficiency is more or less constant, only the amount of fuel injected
varies.
Regards
Mike
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Michael Rigby-Jones
2007-07-02 09:16:43 UTC
Permalink
-----Original Message-----
On Behalf Of Rich
Sent: 02 July 2007 08:36
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Simple fuel-saver, so they say
Yes, that is true. The heat absorption of the engine components do
contribute to a loss of efficiency. However, the forces
acting normal to
the direction of displacement do not add directly to the piston
displacement. The argument for the random collision is
inconsequential
because the forces are not significantly redirected.
The molecular expansion would have to be uniformly
directed along the
axis of travel of the piston for "all" of the forces to be
utilized. But
that is impossible.
If we could coax molecules to expand in one direction only then I think the piston engine would already be a historical curiosity!

Regards

Mike

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Rich
2007-07-03 03:30:07 UTC
Permalink
Well said, Mike.

----- Original Message -----
From: "Michael Rigby-Jones" <Michael.Rigby-Jones-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Monday, July 02, 2007 5:16 AM
Subject: RE: [EE] Simple fuel-saver, so they say
Post by Michael Rigby-Jones
-----Original Message-----
On Behalf Of Rich
Sent: 02 July 2007 08:36
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Simple fuel-saver, so they say
Yes, that is true. The heat absorption of the engine components do
contribute to a loss of efficiency. However, the forces
acting normal to
the direction of displacement do not add directly to the piston
displacement. The argument for the random collision is
inconsequential
because the forces are not significantly redirected.
The molecular expansion would have to be uniformly
directed along the
axis of travel of the piston for "all" of the forces to be
utilized. But
that is impossible.
If we could coax molecules to expand in one direction only then I think
the piston engine would already be a historical curiosity!
Regards
Mike
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Peter P.
2007-06-28 13:39:20 UTC
Permalink
Post by Rich
combustion is not used (BUT in MHO it could be). The mixture is always on
the rich side to guarantee predictable and repeatable ignition without any
dead cycles. The rich mixture is another inefficiency because it results in
less than complete combustion. There are some other kinetic factors like
Most modern engines run super-lean and recirculate exhaust to mitigate the
detonation (this reduce oxygen % and thus flame speed).
Post by Rich
Increasing the compression would create a richer oxygen environment to
produce a hotter burn (more heat) which is the whole objective of the IC
engine. But too much oxygen would move the process from burn to explode
which would damage the engine. There is the real limit on mileage and
A suitable ECU can cope with 100% oxygen (see above). The cylinder
metallurgy cannot cope with 100% oxygen.
Post by Rich
efficiency: How much heat you can get from the burn of the fuel without
exploding it. In diesel engines the compression ratio is much higher and it
is so oxygen rich that a spark is not required to initiate the burn. But
here, again, the efficiency limit is imposed by the rate of oxidation; too
fast and BOOM, you wrecked your engine. The reason diesel can tolerate
higher oxygen ratios is because there is less BTU per unit volume than for
gasoline, of whatever octane.
Actually Diesel fuel has higher BTU/cu. ft than Otto, precisely because of
higher compression. And Diesel can cope with 100% oxygen with
recirculation as above. The reason Diesel is more efficient is the higher
compression and the different burn characteristics of heavy fuel (it won't
really detonate). The same increase in efficiency reduces the heat load on
the cylinder and allows more boost. The metallurgy is the actual limiting
factor for Diesel boost, as anyone running tuned Diesels will tell you,
there is no such thing as too much boost for a Diesel, but melting the
engine or making the exhaust glow red hot is a definite possibility.

High efficiency compound power stations use a blown Diesel followed by
reheat and a steam turbine to reach very high efficiencies. Alternatively
a gas turbine is used instead of the Diesel.
Post by Rich
So to get more mileage you need to figure out how to get more heat per
unit fuel, a more complete burn and keep on the safe side of explosion.
Now here is an interesting point. Some people talk about alternative
energy on one side of the page and better efficiency on the other side.
So they came up with ethanol. Ethanol has less BTU per unit volume than
Gasoline. To save energy they advocate mixing ethanol with the gasoline and
at some pumps it is already premixed. Question! How is mixing something
with less energy with something with more energy going to result in
increased efficiency, or better mileage, and so on. The heat produced by
the burn will actually decrease, resulting on lower power. The problem of
repeatable ignition cycles requiring a richer mixture remains. Is it an
oxymoron? Or is it simply a moron idea? I am baffled by it.
It is an oxy (pun!) moron, and the joke is on the buyer. Ethanol is
'pre-oxydized'. Fuel is sold by the gallon but it should be sold by the
pound (weight) or more exactly, by the BTU, converted to weight. All
professional fuel measurements are in lbs/hr (or HP or mile or kW such) at
given BTU (or equivalent kg/hr). Also ALL bulk fuel sales are by lbs or
tons. There is no such thing as selling by the gallon excepting for the
suckered end customer. Even when bulk barrels are sold temperature is
accounted for to arrange for the amount in bulk barrels at STP. The reason
is that fuel varies in volume, with temperature, besides having various
BTU grades. When one buys gas in winter one buys more gas by weight per
gallon than in summer. The difference is large enough that it can wipe out
smaller effects (like economizers and engine tuning).

The current way to sell fuel by the gallon regardless of temperature while
leaving the makers to 'blend' it as they see fit is a license to steal
imho. Meanwhile the state authorities that tax fuel tax it happily by the
gallon regardless of density and BTU content. Switching to E85 increases
tax income (at the same tax rate) by up to 30% for the same mileage. So if
E85 would get a '10% tax break' then the tax authority would still gain by
a large margin.


Ethanol mixed into gas (specifically E85 and the like) is effectively a
hole in the consumer's pocket and liable to bring a bad name to Ethanol
fuel. Not only does the gas prevent the engine to be compressed up to 15:1
as pure ethanol and ethanol/water (incidentally W85 defined as 85% ethanol
and 15% water would be a workable fuel) would, but it adds all the
problems of limited storage time (if any water gets in E85 the fuel will
separate) and reduces the BTU thus increasing consumption by the gallon
gauge by up to 30%, as recently compared by an auto magazine's independent
testing. A boon for the taxman and for fuel Co's, and a bad name for
Ethanol. With this the taxman and the fuel co's hit two rabbits with
somebody else's bullet imho.

A fair way to sell fuel is by BTU, specified by mass (lbs or kgs). This
deletes the temperature effect and even makes E85 comparisons fair since
the price should reflect $/BTU and not the treacherous $/gallon (or
liter).

And to run an engine on ethanol, one runs it on 100% ethanol or 85-95%
ethanol + water + nitrous or such, at 15:1 and higher (possible with
exhaust recirculation) compression, where the added efficiency by
compression increase more than compensates for the lower BTU/lb (not
gallon!) of ethanol. In fact, to be fair, car mileage should be given in
miles/BTU (or miles/kWh or equivalent). That would allow electric and
other cars to be compared too, and would be a direct measure of
efficiency.

And, incidentally, CO2 exhaust, 'green footprint' etc is also related to
fuel mass and type, not volume. Look up any chemical reaction and you'll
see that *everyone* balances reactions by mass, not by volume, from 9th
grade on at least. That makes suckers who buy fuel by volume in summer
less intelligent than 9th graders imho.

And if you think I'm just babbling, read about a lawsuit in Utah that
tries to force authorities to make gas retailers add temperature
compensation to gas pumps:

http://www.petrolworld.com/news/northamerica/?
guid=66adf828-8350-45b1-bc56-918b7d8fbd84

(paste on 1 line)

Oops.

Peter P.
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Peter P.
2007-06-28 17:46:22 UTC
Permalink
Post by g***@public.gmane.org
Not rocket science, guys - You want MPGs, slow down.
Had my nose rubbed in it driving a VW Bus for 30 years;
<at> 35 mph 24 mpg, 55 mph 16 mpg. It'd manage 70+ mph
on the flat, but the fuel consumption was intolerable, and
a cross wind would put you in the klong, so did'nt spend
enough time in that part of the envelope to get real numbers.
Hehe, the early VW buses had a reputation for having the 'aerodynamics of
a brick'

http://www.vwbusstop.demon.nl/bushistory/

Later there were spoiler kits and the like to improve it. Of course driving
slower reduces aerodynamic loss but while one's at it one may switch to
non-balloon tyres and run them at max. allowed pressure (not in summer) and tune
the engine to run better at low power with leaner mixture (plugs and timing), as
well as change the transmission oil to the lightest possible.

Peter P.
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Lee Jones
2007-06-28 09:45:00 UTC
Permalink
Post by Cedric Chang
Post by Rich
It is interesting that many people believe that the fuel actually
explodes in the cylinder and drives the piston against the crankshaft.
That is hardly the case. The IC engine is a heat engine just as the
steam engine is a heat engine. The mileage depends on the efficiency
of the conversion of fuel into heat. The fuel-air mixture burns: it
does not explode.
Correct.
Post by Cedric Chang
Post by Rich
When the cylinder comes up it compresses the air creating an oxygen
rich environment for the fuel mixture.
Movement of the piston during the compression stroke does not change
the ratio between oxygen, nitrogen, and other trace elements in air.
The cylinder just contains compressed air (plus fuel).
Post by Cedric Chang
Post by Rich
The spark causes the fuel to
burn and the heat from the oxidation of the fuel causes the fluid
molecules inside the cylinder to expand rapidly and equally in all
directions. The force acting on the piston head from the expanding
molecules is what moves the crank shaft.
Correct.
Post by Cedric Chang
Post by Rich
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency.
Another use of the high pressure burning air-fuel mixture is to get
behind the rings and press them up against the cylinder walls. This
provides an adjustable seal between the moving piston & the imperfect
cylinder wall (which has taper, out of round, etc).
Post by Cedric Chang
Post by Rich
But the optimum fuel-air mixture for the most complete
combustion is not used (BUT in MHO it could be). The mixture is
always on the rich side to guarantee predictable and repeatable
ignition without any dead cycles. The rich mixture is another
inefficiency because it results in less than complete combustion.
There are some other kinetic factors like the inertial forces and
migration of the mixture through the manifold, which is why polished
ports and manifolds yield more power.
An additional problem is keeping the air-fuel mixture exactly
the same in each cylinder.

The intake manifold runners vary in flow resistance to each cylinder.
If the fuel is inserted at the throttle butterflies, via carburetor
or throttle bore fuel injection, then the mixture can vary during its
transit to individual cylinders. With per-port fuel injection, the
air (moslty homogenous) moves to each cylinder and the appropriate
amount of fuel is sprayed right at the intake valve thus attempting
to keep air-fuel mixture identical in each cylinder. This allows
the controller to run the engine closer to the optimum air-fuel
mixture point for the prevailing conditions..

(In older, very high performance engines, one carburetor barrel and
a seperate intake manifold runner was dedicated to feeding each the
mixture into each cylinder, i.e. 8 Webers on a V8 engine.)

Part of the power increase of polished manifold runners is simply
the ability to insert _more_ air-fuel mixture into the cylinder;
increasing the volumetric efficiency.
Post by Cedric Chang
Post by Rich
Increasing the compression would create a richer oxygen environment
to produce a hotter burn (more heat) which is the whole objective of
the IC engine.
Again, higher compression does not change the oxygen ratio. Higher
compression converts more of the heat energy into "push" on the piston.
It also requires a higher octane level fuel to prevent the mixture
from exploding. (Octane rating * is mostly the ability of a fuel
to not explode under specific engine operating points.)
Post by Cedric Chang
Post by Rich
But too much oxygen would move the process from burn
to explode which would damage the engine. There is the real limit
on mileage and efficiency: How much heat you can get from the burn
of the fuel without exploding it. In diesel engines the compression
ratio is much higher and it is so oxygen rich that a spark is not
required to initiate the burn. But here, again, the efficiency limit
is imposed by the rate of oxidation; too fast and BOOM, you wrecked
your engine. The reason diesel can tolerate higher oxygen ratios is
because there is less BTU per unit volume than for gasoline, of
whatever octane.
And when a diesel engine is cold, a glow plug is usually used to
initiate combustion. When warm, the act of highly compressing the
air-fuel mixture is sufficient to ignite the charge. Plus diesel
engines are built stronger to withstand the higher stresses.
Post by Cedric Chang
Post by Rich
So to get more mileage you need to figure out how to get more heat
per unit fuel, a more complete burn and keep on the safe side of
explosion.
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
Modern engines have a knock sensor. The computer controller leans
the air-fuel mixture as much as possible, usually based on an O2
sensor in the exhaust system. When it senses the fuel exploding via
the knock sensor, it enrichens the mixture "enough" to stop it.

Besides mileage, most of these engine control strategies reduce the
emissions which is most of the driving force behind their design.
The government emissions limits were set prior to the fleet mileage
goals. And emissions limits are harder limits; poor mileage just
results (in the US) an economic penalty on the manufacturer,
either directly through government penalties or loss of buyers..

Lee Jones

* higher octane rating of aircraft engine fuels during world war 2
allowed the allied powers to use higher compression ratios and
produce higher engine power output for a given engine weight
which allowed for more performance or more range... Water
injection was also used to prevent knock during extreme power
operation (but the amount of water available was limited).
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Gerhard Fiedler
2007-06-28 13:42:41 UTC
Permalink
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
Modern engines have a knock sensor. The computer controller leans the
air-fuel mixture as much as possible, usually based on an O2 sensor in
the exhaust system. When it senses the fuel exploding via the knock
sensor, it enrichens the mixture "enough" to stop it.
I don't think the "knocking" is fuel exploding. AFAIK it is fuel expanding
before the piston reached its end position. IIRC, you can make any engine
knock without changing the mixture, just by moving the ignition point
forward. And you can make it stop knocking by moving the point back. Since
the time between the spark and the mixture expanding depends on many
factors, and you want the mixture to start expanding right after the piston
reached the dead point but not before, they control the ignition point now
with knock sensors.

Gerhard
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Michael Rigby-Jones
2007-06-28 15:15:47 UTC
Permalink
-----Original Message-----
On Behalf Of Gerhard Fiedler
Sent: 28 June 2007 14:43
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Lee Jones
Post by Cedric Chang
I don't know the difference between burn fast and explode.
Does fuel
Post by Lee Jones
Post by Cedric Chang
burn fast and if the engine flies apart then the fuel was
"exploding"
Post by Lee Jones
Post by Cedric Chang
?
Modern engines have a knock sensor. The computer controller
leans the
Post by Lee Jones
air-fuel mixture as much as possible, usually based on an O2
sensor in
Post by Lee Jones
the exhaust system. When it senses the fuel exploding via the knock
sensor, it enrichens the mixture "enough" to stop it.
I don't think the "knocking" is fuel exploding. AFAIK it is
fuel expanding before the piston reached its end position.
IIRC, you can make any engine knock without changing the
mixture, just by moving the ignition point forward. And you
can make it stop knocking by moving the point back. Since the
time between the spark and the mixture expanding depends on
many factors, and you want the mixture to start expanding
right after the piston reached the dead point but not before,
they control the ignition point now with knock sensors.
http://www.motorcycle.com/how-to/wrenching-with-robchemical-soup-the-mystery-of-detonation-3420.html

Regards

Mike


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Russell McMahon
2007-06-29 07:12:43 UTC
Permalink
Post by Gerhard Fiedler
I don't think the "knocking" is fuel exploding.
See eg

http://en.wikipedia.org/wiki/Engine_knocking

and note especially under "detonation".

Gargoyle will supply various other references.


Russell.
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Rich
2007-07-02 05:59:26 UTC
Permalink
If you are talking about pre-ignition pinging, it will occur is the fuel
mixture is ignited before the piston reaches its design position relative to
top dead center. It will usually cause a bucking. However, if the fuel
explodes it can damage the engine. It can throw a rod or bread a piston.
The energy of an explosion is greater than the energy of a controlled burn
even a pre-ignition.

The difference between burn and explode is extremely important. The
chemistry is quite mature and I think available on the net. If not it is in
most chemistry books.
Burn and explode related to the IC engine is the same as Burn and
explode in a propane stove. When you cook, the oxidation rate of the
propane should be burn and not explode. The flame on an acetylene torch can
be made hotter or less hot according to the oxygen mixture adjustment.
Rapid oxidation is involved in explosives.
An explosion will occur if the oxidation rate increases to the specific
explosion point of whatever molecular structure is involved. In chemical or
pharmaceutical plants as well as in mining there is a need to determine the
Least Explosive Level (LEL). A company by the name (I think) is Mine Safety
Equipment makes such detection instrument.


----- Original Message -----
From: "Gerhard Fiedler" <lists-y1ricOmiHYazCjwMszBmGVaTQe2KTcn/@public.gmane.org>
To: <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 9:42 AM
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Gerhard Fiedler
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
Modern engines have a knock sensor. The computer controller leans the
air-fuel mixture as much as possible, usually based on an O2 sensor in
the exhaust system. When it senses the fuel exploding via the knock
sensor, it enrichens the mixture "enough" to stop it.
I don't think the "knocking" is fuel exploding. AFAIK it is fuel expanding
before the piston reached its end position. IIRC, you can make any engine
knock without changing the mixture, just by moving the ignition point
forward. And you can make it stop knocking by moving the point back. Since
the time between the spark and the mixture expanding depends on many
factors, and you want the mixture to start expanding right after the piston
reached the dead point but not before, they control the ignition point now
with knock sensors.
Gerhard
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Tobias Gogolin
2007-07-02 06:48:45 UTC
Permalink
Post by Rich
The energy of an explosion is greater than the energy of a controlled burn
even a pre-ignition.

not necessarily but yes it is more violent since its flame front speed is
incompatible with the involved hardware

Pistons cant move that fast
so shock Waves bounce around and cause standing waves concentrating energy
in points
that causes the fragmentation of pistons one typically finds

Lean engines (magermotoren) can have stoichiometric regions more easily in
which detonations (that's the way automotive pros refer to explosions versus
deflagrations)
occur
so the question is usually to keep the fuel together in a smaller swirl, or
to use things like water injection to provide slow burning areas
anyhow
Long term goal of the GoBox is to implement a Parallel processing FPGA based
Ion sensing motor controller!

Ion sensing is an important keyword here, it uses common spark plugs as
sensors in between the times when thy are used to ignite the mixture!
Post by Rich
If you are talking about pre-ignition pinging, it will occur is the fuel
mixture is ignited before the piston reaches its design position relative to
top dead center. It will usually cause a bucking. However, if the fuel
explodes it can damage the engine. It can throw a rod or bread a piston.
The energy of an explosion is greater than the energy of a controlled burn
even a pre-ignition.
The difference between burn and explode is extremely important. The
chemistry is quite mature and I think available on the net. If not it is in
most chemistry books.
Burn and explode related to the IC engine is the same as Burn and
explode in a propane stove. When you cook, the oxidation rate of the
propane should be burn and not explode. The flame on an acetylene torch can
be made hotter or less hot according to the oxygen mixture adjustment.
Rapid oxidation is involved in explosives.
An explosion will occur if the oxidation rate increases to the specific
explosion point of whatever molecular structure is involved. In chemical or
pharmaceutical plants as well as in mining there is a need to determine the
Least Explosive Level (LEL). A company by the name (I think) is Mine Safety
Equipment makes such detection instrument.
----- Original Message -----
Sent: Thursday, June 28, 2007 9:42 AM
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Gerhard Fiedler
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding"
?
Post by Gerhard Fiedler
Modern engines have a knock sensor. The computer controller leans the
air-fuel mixture as much as possible, usually based on an O2 sensor in
the exhaust system. When it senses the fuel exploding via the knock
sensor, it enrichens the mixture "enough" to stop it.
I don't think the "knocking" is fuel exploding. AFAIK it is fuel
expanding
Post by Gerhard Fiedler
before the piston reached its end position. IIRC, you can make any
engine
Post by Gerhard Fiedler
knock without changing the mixture, just by moving the ignition point
forward. And you can make it stop knocking by moving the point back.
Since
Post by Gerhard Fiedler
the time between the spark and the mixture expanding depends on many
factors, and you want the mixture to start expanding right after the piston
reached the dead point but not before, they control the ignition point
now
Post by Gerhard Fiedler
with knock sensors.
Gerhard
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Tobias Gogolin
cel. (646) 124 32 82
skype: moontogo
messenger: usertogo-***@public.gmane.org

You develop an open source motor controller at
http://groups.yahoo.com/group/GoBox
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Alan B. Pearce
2007-07-02 09:57:48 UTC
Permalink
Post by Rich
Burn and explode related to the IC engine is the same as Burn
and explode in a propane stove.
Clearly some guys in Scotland didn't do their sums to work out how to
explode propane bottles ...

http://www.timesonline.co.uk/tol/news/uk/crime/article2013255.ece for those
who haven't kept up with the news.
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Russell McMahon
2007-07-02 12:47:49 UTC
Permalink
Post by Alan B. Pearce
Post by Rich
Burn and explode related to the IC engine is the same as Burn
and explode in a propane stove.
Clearly some guys in Scotland didn't do their sums to work out how
to explode propane bottles ...
They were clearly incredibly incompetent and uninformed when it came
to bomb making and not too clued up about effective uses of motor
vehicles either. Getting it on the tarmac at the right time would have
been potentially more effective :-(. If you get very large amounts of
Propane you can get something very nasty and close to a proper
explosion as the expanding liquid / gas cloud mixture ratio "comes
right" (such as in the tragic Spanish holiday camp accident quite some
decades ago) but in bottle in car size quantities I'm sure there are
more effective materials available. In very small sizes rupturing a
Propane tank in the presence of even an enthusiastic ignition source
can be most unspectacular (ask me how I k ...). Fortunately these guys
were extremely uninformed and can't have done much practical R&D or
testing.

If you work for the FBI call and I can outline a much more potentially
effective use of Propane based on my observations in the US a few
years ago :-(. If you work for anyone else don't bother.



Russell
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Alan B. Pearce
2007-07-02 13:13:40 UTC
Permalink
In very small sizes rupturing a Propane tank in the
presence of even an enthusiastic ignition source
can be most unspectacular (ask me how I k ...).
It can be very spectacular though. In the news here there seems to be a
thread where it is reckoned that what the Glasgow and London car bombers
were trying to do is very similar to many of the car bombs in Baghdad.

When the London ones were discovered, they had a guy demonstrate on TV what
sort of flame front could be achieved with a small propane tank and a gallon
of petrol. That was stand well back before igniting electronic touch paper.
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Rich
2007-07-02 15:51:49 UTC
Permalink
Yes! We can sometimes be thankful for idiot's failures.

----- Original Message -----
From: "Alan B. Pearce" <A.B.Pearce-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Monday, July 02, 2007 5:57 AM
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Alan B. Pearce
Post by Rich
Burn and explode related to the IC engine is the same as Burn
and explode in a propane stove.
Clearly some guys in Scotland didn't do their sums to work out how to
explode propane bottles ...
http://www.timesonline.co.uk/tol/news/uk/crime/article2013255.ece for those
who haven't kept up with the news.
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Rich
2007-07-02 07:03:41 UTC
Permalink
Thank you for your excellent comments, Lee. I enjoy reading the various
comments and replies. The ratio I am referring to is not the ratio of
oxygen to nitrogen, which is impossible to change by common compression
methods. I was referring to the ratio of oxygen to fuel vapor.

The compression increases the quantity of air. There is a greater quantity
of oxygen than would be present in uncompressed air. While the ratio of
oxygen to nitrogen is not altered these is a greater amount of oxygen,
albeit a greater amount of both. The trace elements are very small and do
not contribute significantly to the gas expansion. The nitrogen is heated
and expands creating the forces inside the cylinder.

But if the compression occurs without piston displacement, as you say, Lee,
then how is the compression accomplished?

Yes, that is true. Keeping the mixture optimized in the separate cylinders
is a challenge. That is why I mentioned, but did not discuss in detail, the
inertial forces of the mixture particles and the importance of low friction
and aerodynamic manifold design.

I see what you are saying about the ratio. I did not refer to the ratio of
oxygen to nitrogen but the ratio of oxygen to fuel vapor. Sorry is I was a
bit nebulous on that point.

Yes, the octane rating of the fuel also relates to pre-ignition as well.
This is the purpose of cracking process of the petroleum; to alter the
octane.

Yes, of course, the diesel engine is designed differently and the use of
glow plugs for low temperature operation is common. However, the Diesel
engine is still an internal combustion that operates on the principle of
converting fuel energy to heat energy. It is a heat engine as is the
gasoline or propane IC engine.

The intention to reduce emissions has been part of the IC engine design
criteria for many decades. The emissions are reduced in large measure by
effecting more complete combustion.



----- Original Message -----
From: "Lee Jones" <lee-k0F1T7XnjilLq+***@public.gmane.org>
To: <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 5:45 AM
Subject: Re: [EE] Simple fuel-saver, so they say lean mixture
Post by Lee Jones
Post by Cedric Chang
Post by Rich
It is interesting that many people believe that the fuel actually
explodes in the cylinder and drives the piston against the crankshaft.
That is hardly the case. The IC engine is a heat engine just as the
steam engine is a heat engine. The mileage depends on the efficiency
of the conversion of fuel into heat. The fuel-air mixture burns: it
does not explode.
Correct.
Post by Cedric Chang
Post by Rich
When the cylinder comes up it compresses the air creating an oxygen
rich environment for the fuel mixture.
Movement of the piston during the compression stroke does not change
the ratio between oxygen, nitrogen, and other trace elements in air.
The cylinder just contains compressed air (plus fuel).
Post by Cedric Chang
Post by Rich
The spark causes the fuel to
burn and the heat from the oxidation of the fuel causes the fluid
molecules inside the cylinder to expand rapidly and equally in all
directions. The force acting on the piston head from the expanding
molecules is what moves the crank shaft.
Correct.
Post by Cedric Chang
Post by Rich
The expanding forces against the side walls of the cylinder do not
contribute to the force on the piston head and so contribute to the
inefficiency.
Another use of the high pressure burning air-fuel mixture is to get
behind the rings and press them up against the cylinder walls. This
provides an adjustable seal between the moving piston & the imperfect
cylinder wall (which has taper, out of round, etc).
Post by Cedric Chang
Post by Rich
But the optimum fuel-air mixture for the most complete
combustion is not used (BUT in MHO it could be). The mixture is
always on the rich side to guarantee predictable and repeatable
ignition without any dead cycles. The rich mixture is another
inefficiency because it results in less than complete combustion.
There are some other kinetic factors like the inertial forces and
migration of the mixture through the manifold, which is why polished
ports and manifolds yield more power.
An additional problem is keeping the air-fuel mixture exactly
the same in each cylinder.
The intake manifold runners vary in flow resistance to each cylinder.
If the fuel is inserted at the throttle butterflies, via carburetor
or throttle bore fuel injection, then the mixture can vary during its
transit to individual cylinders. With per-port fuel injection, the
air (moslty homogenous) moves to each cylinder and the appropriate
amount of fuel is sprayed right at the intake valve thus attempting
to keep air-fuel mixture identical in each cylinder. This allows
the controller to run the engine closer to the optimum air-fuel
mixture point for the prevailing conditions..
(In older, very high performance engines, one carburetor barrel and
a seperate intake manifold runner was dedicated to feeding each the
mixture into each cylinder, i.e. 8 Webers on a V8 engine.)
Part of the power increase of polished manifold runners is simply
the ability to insert _more_ air-fuel mixture into the cylinder;
increasing the volumetric efficiency.
Post by Cedric Chang
Post by Rich
Increasing the compression would create a richer oxygen environment
to produce a hotter burn (more heat) which is the whole objective of
the IC engine.
Again, higher compression does not change the oxygen ratio. Higher
compression converts more of the heat energy into "push" on the piston.
It also requires a higher octane level fuel to prevent the mixture
from exploding. (Octane rating * is mostly the ability of a fuel
to not explode under specific engine operating points.)
Post by Cedric Chang
Post by Rich
But too much oxygen would move the process from burn
to explode which would damage the engine. There is the real limit
on mileage and efficiency: How much heat you can get from the burn
of the fuel without exploding it. In diesel engines the compression
ratio is much higher and it is so oxygen rich that a spark is not
required to initiate the burn. But here, again, the efficiency limit
is imposed by the rate of oxidation; too fast and BOOM, you wrecked
your engine. The reason diesel can tolerate higher oxygen ratios is
because there is less BTU per unit volume than for gasoline, of
whatever octane.
And when a diesel engine is cold, a glow plug is usually used to
initiate combustion. When warm, the act of highly compressing the
air-fuel mixture is sufficient to ignite the charge. Plus diesel
engines are built stronger to withstand the higher stresses.
Post by Cedric Chang
Post by Rich
So to get more mileage you need to figure out how to get more heat
per unit fuel, a more complete burn and keep on the safe side of
explosion.
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
Modern engines have a knock sensor. The computer controller leans
the air-fuel mixture as much as possible, usually based on an O2
sensor in the exhaust system. When it senses the fuel exploding via
the knock sensor, it enrichens the mixture "enough" to stop it.
Besides mileage, most of these engine control strategies reduce the
emissions which is most of the driving force behind their design.
The government emissions limits were set prior to the fleet mileage
goals. And emissions limits are harder limits; poor mileage just
results (in the US) an economic penalty on the manufacturer,
either directly through government penalties or loss of buyers..
Lee Jones
* higher octane rating of aircraft engine fuels during world war 2
allowed the allied powers to use higher compression ratios and
produce higher engine power output for a given engine weight
which allowed for more performance or more range... Water
injection was also used to prevent knock during extreme power
operation (but the amount of water available was limited).
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g***@public.gmane.org
2007-06-28 13:42:28 UTC
Permalink
One of my textbooks has combustion chamber photography
of normal ignition - The flame front starts at the plug and spreads
through the chamber. In detonation multiple ignition sources
appear causing multiple flame fronts, resulting in a much faster
burn. Severe knock is caused by the mixture going off well in
advance of spark - hence "pre-ignition".
Post by Peter P.
Post by Cedric Chang
I don't know the difference between burn fast and explode. Does fuel
burn fast and if the engine flies apart then the fuel was "exploding" ?
In a 10,000 RPM 2-stroke engine total fuel burn occurs in less than 2 msec and
it is not called an explosion. The spark timing must be more accurate than a
tenth of that to avoid problems at high power. 200 usec does not sound like much
for amicro but the rotation timing sensor must be at least twice as accurate
over temperature, voltage and age. A normal car engine that revs up to about
5000 should finish burning anything in 4 msec or less, or there will be flame
out the exhaust. An explosion occurs when the mixture goes off faster than the
speed of sound in it (see deflagration and detonation on Wikipedia). At the
speed of sound at STP in a 1 inch bore engine the flame needs 350 usec to reach
the cylinder wall from the central spark plug. So if the engine must burn in
under 2 msec but 350 usec is the limit for detonation (actually it is more
complicated than that but this is just a beer coaster explanation) the 'normal'
operation is *extremely* close to detonation regime (known as knocking), and
remember that the transition is exponential (flame speed grows exponentially as
conditions near detonation conditions).
Peter P.
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Peter P.
2007-06-28 17:49:24 UTC
Permalink
On the topic of aerodynamics I found a weird photo of a pimped VW beetle. The
beetle is ok but there is an interesting device hanging out the passenger
window. I suspect it is some kind of air conditioning device (makes sense with
that black car in the sun). I suppose it is removed for driving (or not ?).
There are 2 photos at the bottom of this beetle-related page:

http://auto-haus.skynetblogs.be/

does anyone know what that device is ?

thanks,
Peter P.
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g***@public.gmane.org
2007-06-28 13:48:31 UTC
Permalink
Post by Tony Smith
Today I encountered a woman who refused to keep stuff in the office fridge.
The reason was that it was covered magnets. Now this just isn't logical, as
everyone knows magnets are good for you (except electromagnets, which emit
electricity, radiation and bad vibes.) Her home fridge had none, which is
why she was so healthy & happy. I guess the milk didn't get polarised or
something.
You could hear the neurons in her head grinding against each other when I
showed her how a fridge door seal works... :)
ROTFL...

I'm well acquainted with one of her soul sisters - See if I can get
up the nerve to show her your post... :)

Jack
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g***@public.gmane.org
2007-06-28 18:49:23 UTC
Permalink
Hi Peter - Likely an evaporative cooler. JC Whitney used to sell
one similar but not identical to the one pictured.

Jack
Post by Peter P.
On the topic of aerodynamics I found a weird photo of a pimped VW beetle. The
beetle is ok but there is an interesting device hanging out the passenger
window. I suspect it is some kind of air conditioning device (makes sense with
that black car in the sun). I suppose it is removed for driving (or not ?).
http://auto-haus.skynetblogs.be/
does anyone know what that device is ?
thanks,
Peter P.
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g***@public.gmane.org
2007-06-28 19:25:48 UTC
Permalink
Post by Peter P.
Hehe, the early VW buses had a reputation for having the 'aerodynamics of
a brick'
Later ones were'nt much better - Similar to pushing a barn door
mounted to the front fender down the road. :) One learns patience.
24 mpg not too bad for a 1 ton truck, though.
Post by Peter P.
Later there were spoiler kits and the like to improve it.
Mostly made things worse.
Post by Peter P.
Of course driving
slower reduces aerodynamic loss but while one's at it one may switch to
non-balloon tyres and run them at max. allowed pressure (not in summer) and tune
the engine to run better at low power with leaner mixture (plugs and timing), as
well as change the transmission oil to the lightest possible.
Some of these work, although early 70s models were jetted so lean
(for the US market) that fuel economy actually improved by richening
up a bit, allowing one to drive in a higher gear in many situations.
4-into-1 headers were worth a couple mpg too, as well as better top
end, a rare change with no real down side.

Jack
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David VanHorn
2007-06-29 03:03:20 UTC
Permalink
Post by g***@public.gmane.org
Some of these work, although early 70s models were jetted so lean
(for the US market) that fuel economy actually improved by richening
up a bit, allowing one to drive in a higher gear in many situations.
4-into-1 headers were worth a couple mpg too, as well as better top
end, a rare change with no real down side.
My toyota celica, which I installed instant and avg mpg metering in,
got best mileage at 62, and benefitted a lot from shutting down the
exhaust gas recirculation and lowering the idle to about 700 rpm.
Stoplights and sitting in traffic is 0 MPG.
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Rich
2007-07-02 05:39:03 UTC
Permalink
Even though the mixture should be adjusted for altitude, it cannot be made
lean in order to improve engine performance. The purpose for complete
combustion is to reduce unwanted exhaust emissions and to improve engine
performance. Rich and lean become relative terms and can only be related to
engine performance.

----- Original Message -----
From: "David VanHorn" <microbrix-***@public.gmane.org>
To: "Microcontroller discussion list - Public." <piclist-***@public.gmane.org>
Sent: Thursday, June 28, 2007 11:03 PM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by David VanHorn
Post by g***@public.gmane.org
Some of these work, although early 70s models were jetted so lean
(for the US market) that fuel economy actually improved by richening
up a bit, allowing one to drive in a higher gear in many situations.
4-into-1 headers were worth a couple mpg too, as well as better top
end, a rare change with no real down side.
My toyota celica, which I installed instant and avg mpg metering in,
got best mileage at 62, and benefitted a lot from shutting down the
exhaust gas recirculation and lowering the idle to about 700 rpm.
Stoplights and sitting in traffic is 0 MPG.
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Lee Jones
2007-07-02 09:13:12 UTC
Permalink
Post by Rich
Post by Rich
I would like to see the smoke test they ran
Now, my curiosity is piqued and I would like to see what the vortex
is like an what sort of impact that will have on a counter force
presented to the [tailgate] and how that counterforce translates
into added fuel use. The added fuel use could easily be converted
to counter force applied to the tailgate.
Smoke test is difficult to do without a wind tunnel.

An inexpensive method of determining localized ar flow direction
is tufts of yarn. A roll of yarn and a roll of masking tape is
only about $5 -- plus labor to install (yarn removal is optional).

Cut some yarn into pieces 2-3" long. Tape one end only of each
piece of yarn and create a rectangular array of yarn bits on the
surface(s) of interest. In this case, I'd try tufting the top of
the cab, the back of the cab, the entire truck bed, and both(?)
sides of the tailgate on about a 6" x 6" grid.

Then, as you drive, you can see the air flow direction at each
point (yarn attachment) by the way that each piece of yarn is
oriented. Top of the cab might be tough to see, but a passenger
could easily monitor the flow on the cab's back window, in the
bed, and on the tailgate. Try it with tailgate open and then
with the tailgate closed.

Plus, think of the amusement you'll give other drivers as they
see your truck going by with bits of yarn taped all over it. :-)

Lee Jones
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Alan B. Pearce
2007-07-02 10:11:24 UTC
Permalink
Post by Lee Jones
Plus, think of the amusement you'll give other drivers as they
see your truck going by with bits of yarn taped all over it. :-)
Hmm, guess it won't be as funny as the Top Gear team deciding to drive
through Alabama with slogans about being gay painted on their car, was to
the viewers. Had to get away from a mom and pop gas station in a hurry after
a bunch of tough looking types turned up in a pickup ...
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Rich
2007-07-03 03:27:09 UTC
Permalink
I guess it would be amusing. I should wear a silly costume and let someone
else drive :-)

----- Original Message -----
From: "Lee Jones" <lee-k0F1T7XnjilLq+***@public.gmane.org>
To: <piclist-***@public.gmane.org>
Sent: Monday, July 02, 2007 5:13 AM
Subject: Re: [EE] Simple fuel-saver, so they say
Post by Lee Jones
Post by Rich
Post by Rich
I would like to see the smoke test they ran
Now, my curiosity is piqued and I would like to see what the vortex
is like an what sort of impact that will have on a counter force
presented to the [tailgate] and how that counterforce translates
into added fuel use. The added fuel use could easily be converted
to counter force applied to the tailgate.
Smoke test is difficult to do without a wind tunnel.
An inexpensive method of determining localized ar flow direction
is tufts of yarn. A roll of yarn and a roll of masking tape is
only about $5 -- plus labor to install (yarn removal is optional).
Cut some yarn into pieces 2-3" long. Tape one end only of each
piece of yarn and create a rectangular array of yarn bits on the
surface(s) of interest. In this case, I'd try tufting the top of
the cab, the back of the cab, the entire truck bed, and both(?)
sides of the tailgate on about a 6" x 6" grid.
Then, as you drive, you can see the air flow direction at each
point (yarn attachment) by the way that each piece of yarn is
oriented. Top of the cab might be tough to see, but a passenger
could easily monitor the flow on the cab's back window, in the
bed, and on the tailgate. Try it with tailgate open and then
with the tailgate closed.
Plus, think of the amusement you'll give other drivers as they
see your truck going by with bits of yarn taped all over it. :-)
Lee Jones
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Jinx
2007-07-04 23:49:12 UTC
Permalink
At this site, well worth a look around, 10 simple measures to
reduce vehicle fuel consumption

http://www.energysavingtrust.org.uk/

In the Publications section, a report on the state of consumer
electronics/appliances from the 70s to the present. Some good
(efficiency), some not so good (standby, proliferation). Too
many examples to choose quotes

The Rise Of The Machines (5MB pdf)

http://www.energysavingtrust.org.uk/download.cfm?p=4&pid=884

A general synopsis here

"Gadget boom drives energy demand - the ampere strikes back"

http://www.nzherald.co.nz/section/story.cfm?c_id=5&objectid=10449580

=============

Regarding the Magnatronic. A work in progress

Brent Brown and I giving Repco's Automotive Divisional Manager
some things to think about and asked a few probing questions. He's
come back with a rather limp reply so far, and I've not yet heard
back from the Commerce Commission about Repco advertising
"guaranteed 10% fuel savings"
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Alan B. Pearce
2007-07-05 08:47:30 UTC
Permalink
Post by Jinx
The Rise Of The Machines (5MB pdf)
http://www.energysavingtrust.org.uk/download.cfm?p=4&pid=884
Hmm, cell phone to die for on page 2.

But wait - whets this in big red letters on page 6 'If one mobile charger
per household is left on standby, the energy wasted is enough to provide the
electricity needs of 66.000 homes for one year'

They must be real old chargers then ...

Somehow I don't think this is a New Zealand originated document (where will
NZ put the 'extra 2 million extra households' mentions in the caption of the
photo on page 6). And it looks like it is deliberately using old equipment
in the illustrations, cell phone already mentioned, 8 track cartridge
recorder, rather old TV.
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Jinx
2007-07-05 09:18:47 UTC
Permalink
But wait - whats this in big red letters on page 6 'If one mobile
charger per household is left on standby, the energy wasted is
enough to provide the electricity needs of 66.000 homes for
one year'
They must be real old chargers then ...
If you assume 25 million households in the UK, and one charger
per household (I think that's conservative - figures suggest 63m
or 2.5 per household) then, by their estimate, a charger must use
66000/25000000th of a household's power or 0.264%. If the
average UK home uses 12kWh per day or 500W/hr, then the
charger would be about 1.3W. Does that sound reasonable ?
And it looks like it is deliberately using old equipment in the
illustrations, cell phone already mentioned, 8 track cartridge
recorder, rather old TV.
The report is covering the 70s to now, and those appliances
are what was around. I'm sure if 8-tracks were still around
Homer Simpson and Al Bundy would be happy, but you know
they aren't and wouldn't seriously be included in a survey of
today's entertainment gear

This goes into more detail than the Herald

http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/07/04/eaice104.x
ml

Using all that power for appliance stand-by is such a waste and
it's only going to get worse. Some education about turning stuff
off at the wall is really needed. And also about big TVs. Fancy
a large plasma using 1.7kW !! My wallet feels nervous when I
put the one-bar heater on for an hour to take the chill off the room.
Imagine the power used to watch garbage and repeats for 8-10
hours a day
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Gerhard Fiedler
2007-07-05 10:25:04 UTC
Permalink
If the average UK home uses 12kWh per day or 500W/hr,
Just a nitpick for the unsuspecting reader (since the thing with units is
confusing enough <g>): 12kWh/day would be 500W (not 500W/hour).

Using the trick with units with all numbers, this could go like this:

12 kWh/day = (12 kWh/day) / (24 h/day) = 12/24 kW = 500 W


It's always again impressive how small things become massive when you
multiply them by the huge numbers of people we are today. It's pretty
evident that our reproductive capacity is way ahead of many other
capacities of ours... :)

Gerhard
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Lee Jones
2007-07-02 09:23:34 UTC
Permalink
Some further comments on yarn tufting...
Post by Lee Jones
Post by Rich
Post by Rich
I would like to see the smoke test they ran
Now, my curiosity is piqued and I would like to see what the vortex
is like an what sort of impact that will have on a counter force
presented to the [tailgate]
An inexpensive method of determining localized ar flow direction
is tufts of yarn.
Cut some yarn into pieces 2-3" long.
On reflection, you might want to make the tufts of yarn longer,
say 4-6" (maybe longer) for a pickup truck.

And if you're using a search engine, "yarn tufting" works but gets
lots of hits on carpet making too. Try "flow visualization". One
page I found quickly was University of Washington

http://www.uwal.org/uwalinfo/techguide/flowvis.htm

It talks about several flow visualization techniques.

Lee Jones
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