Magnets, apple corers and other fuel saving devices

"Don Stauffer" > wrote in message
...
Only solutions- hard- are to greatly
> increase the operating temp of engine, and make long stroke, slow
> turning engines, which are big and heavy, and while a bit more fuel
> efficient, raise the horsepower-needed requirement (self-defeating, of
> course).

Increasing the efficiency of fuel burned is of course the goal. I did some
calculations
recently taking the thermal equivalent of mechanical horsepower, and
relating it to
heat content of gasoline per unit time. (I know that theory and practice
here diverge a
bit, but for a given horsepower generation there is a direct relationship to
fuel burned per
unit time)

One horsepower is 0.7547 kiloJoules per second. Heat energy to be derived
from gasoline
is about 50 kiloJoules per gram.

If you drive 70 miles in one hour, and use 1 gram per second, that is 3600
grams, or approximately
one US gallon (hence 70 miles per gallon). Backing everything up, this
would have generated 67
thermal horsepower at 100% conversion efficiency.

All things considered, to attain 25-30 mpg on some of todays cars is a
pretty decent feat, considering
the above ultimate limitations.

Doug Warner wrote:
> "Daniel J. Stern" > wrote:
>
>
> >You should've been over on rec.autos.makers.chrysler early last week. Some
> >ignorant dip**** calling himself "Whoever" was arguing that restricted air
> >filters don't reduce fuel economy. He dug himself a hole most of the way
> >to China, making all kinds of hilarious claims regarding having formerly
> >designed EFI system, talking about how the O2 sensor controls the fuel
> >injectors' pulsewidth during open-loop operation, etc.
>
> I read you original "discussions" and then did some more research.
> Neither the TPM or the MAF have full control over fuel flow.
> Although, per this
> article:http://www.asashop.org/autoinc/jan97/techtotech.htm
> the TPS has less influence than the MAF..
> I suspect this may vary between systems..

Agreed, except what is a TPM?

I describe sensor importance this way: MAF is the big dog, TPS input
is very important, coolant temp very important though not a quick
response input like the previous two, and the O2 sensor(s) provide
feedback so the ECM can determine which output values to dictate by use
of a programmed data table.

Toyota MDT in MO

> writes:

>"Steve W." > wrote in message
...
> It produces hydrogen rich
>> bubbles before being introduced into the engine draft" I have to agree
>> with PM when they ask anyone to explain how it works.

>Hundred percent agree. Many scam artists in a lot of fields use enough
>scientific buzzwords to
>impress and amaze the uneducated. There ought to be a law...

That people be educated?

"Ryan Underwood" > wrote in message
...
> > writes:
>
> >Hundred percent agree. Many scam artists in a lot of fields use enough
> >scientific buzzwords to
> >impress and amaze the uneducated. There ought to be a law...
>
> That people be educated?

Maybe that is reaching a little far, Ryan ;>).

wrote:
>
> All things considered, to attain 25-30 mpg on some of todays cars is a
> pretty decent feat, considering
> the above ultimate limitations.
>
>
>

Indeed. Present auto engines considerably exceed the efficiency my old
thermodynamics prof said was the maximum a car engine would ever reach.
There is still a ways to go, but the easy fixes are already being
used, and it will be pretty hard to go much higher.

If we can get very high speed feedback control of injection, I see the
direct cylinder injection possibly allowing a bit higher CR in something
like a pseudo-Diesel cycle.

On Tue, 20 Sep 2005 08:50:45 -0500, Don Stauffer wrote:

> wrote:

[snip>

> Indeed. Present auto engines considerably exceed the efficiency my old
> thermodynamics prof said was the maximum a car engine would ever reach.

Huh? I mean... was he talking about the maximum theoretical thermodynamic
efficiency, or about how far up to that maximum the efficiency in his
opinion would be able to go?

shakiro

[snip>

"shakiro" > wrote in message
...
> On Tue, 20 Sep 2005 08:50:45 -0500, Don Stauffer wrote:
>
> > wrote:
>
> [snip>
>
> > Indeed. Present auto engines considerably exceed the efficiency my old
> > thermodynamics prof said was the maximum a car engine would ever reach.
>
> Huh? I mean... was he talking about the maximum theoretical thermodynamic
> efficiency, or about how far up to that maximum the efficiency in his
> opinion would be able to go?
>
> shakiro
>
> [snip>

"shakiro" > wrote in message
...
> On Tue, 20 Sep 2005 08:50:45 -0500, Don Stauffer wrote:
>
> > wrote:
>
> [snip>
>
> > Indeed. Present auto engines considerably exceed the efficiency my old
> > thermodynamics prof said was the maximum a car engine would ever reach.
>
> Huh? I mean... was he talking about the maximum theoretical thermodynamic
> efficiency, or about how far up to that maximum the efficiency in his
> opinion would be able to go?
>
> shakiro

I am interested also.

You may all remember that some 40-50 years ago,
engineers calculated that a 'car' would never be able to exceed 140 mph
in the quarter mile. So much for that.

I remember professors talking in terms of 25-35% efficiency for an IC
engine, I believe.

As I mentioned in my original post, 'theory and practice tend to diverge'.
Thermal efficiency (or thermodynamic efficiency) is probably still not
so very great, but has probably improved since those days.

Transmissions, engines, etc combine to give reasonable speed and
acceleration (with minimized losses) without usually coming anywhere
close to the published maximum horsepower specifications (which are
often bogus to begin with). I think this is the most significant factor
behind the good mileage we get now.

Smoky Yunick worked on adiabatic engines as a consultant during
his 'retirement' and made considerable headway. We are closer to
being able to build such high temperature engines today than ever
before. Lubricants can be made that will hold up near 200C, and
metallurgy/ceramics can run in that range and much higher easily
enough. To go significantly higher, organic lubricants may not be
able to hold the mark....at least, not yet. Eutectic fluids might do it
now.

Interesting possibilities, anyway.

shakiro wrote:
> On Tue, 20 Sep 2005 08:50:45 -0500, Don Stauffer wrote:
>
>
wrote:
>
>
> [snip>
>
>
>>Indeed. Present auto engines considerably exceed the efficiency my old
>>thermodynamics prof said was the maximum a car engine would ever reach.
>
>
> Huh? I mean... was he talking about the maximum theoretical thermodynamic
> efficiency, or about how far up to that maximum the efficiency in his
> opinion would be able to go?
>
> shakiro
>
> [snip>
The later. He felt we had perfected it. This was before higher octane
fuels, higher temp thermostats, and the improved oils and sealed,
pressurized systems that allowed the later.

wrote:
mile. So much for that.
>
> I remember professors talking in terms of 25-35% efficiency for an IC
> engine, I believe.
>

This prof figured 30% would be about absolute max. My understand that
present car engines are at least 35% max, maybe a point or so higher,
even. 'course, I have heard that industrial diesels are in the high
40s, and steam turbines near 50%.

That figure for car engines is best efficiency, at optimum load and rpm.
Average over a real urban driving cycle is of course much less.