[Vwdiesel] More Power From Insulation (Science Again) TBC's ,SAE's and SHC's; by MGS and MRS

[Mark Shepherd]

Mark I, I did not know you were schooled in engineering..

... Alas I hide my education deeper than my wallet in my
pocket ;o)...
Miser

Yes, it was I who posted about the SAE papers on this
subject.  I have read
every paper on this subject up to about 2000.  The general
consensus was, that
TBC's do not show appreciable increase in specific output,
and this mostly due
to a net loss in VE because of intake charge heating.

...Does this apply to diesels and turboed diesels quite the
same way? Intercooled?...
Miser

Those of you into the racing scene may be aware of a fellow
named Dave Williams
in Arkansas, who put a fully TBC coated 4 cylinder gas
engine together a while ago.
 He noted some strange things:
 Power nearly same as non-TBC'd engine, total insensitivity
to timing advance, and no heat from the heater.

...Whilst the latter is reinforcing the effectiveness of the
coating; what can we deduce from the former?
that the combustion is not being instigated by the spark
plugs?
If the energy from combustion is not passing through the
barrier and you say it's not being used as extra work done,
then where can it be going?
 If it is thought that the new charge is being preheated;
are the experimenters suggesting the coating has a high
specific heat capacity?
It looks like it may be similar to aluminium weight wise...
[Why dont we use SHC's in volume format?]...
Miser

  On a diesel engine that already has a difficult time
producing enough waste heat to run a heater core, it might
not make sense to do this to an engine that will spend
significant time in
northern climates.

...Whilst you chaps across the pond do have some pretty cold
periods; are you suggesting that diesels don't get as hot as
gassers?
A cure would be a smaller radiator or a shield.
As I mentioned recently my TD warms up pretty quickly.
(Although my father's Citroen never gets as hot)...
Miser

As I stated on several other forums, TBC's make sense only
from a durability standpoint,
where engine longevity is of paramount concern.  IE, you
have an engine that
is stressed beyond it's normal operating parameters, and you
use the TBC's to crutch
it.


> -----Original Message-----
> From: Mark Shepherd [mailto:mark at shepher.fsnet.co.uk]
> Sent: Sunday, February 13, 2005 8:39 PM
> To: vwdiesel at vwfans.com
> Subject: [Vwdiesel] More Power From Insulation (Science
Again)
>
>
> Ok it's not the weekend (for me now) but this science
thread
> is not entirely OT
> A few weeks ago I queried whether we could 'insulate' the
> piston face and ignition chamber to reduce some of the 30%
> energy losses to the coolant.
> Loren kindly pointed me to a site that provides coatings
for
> engine chambers.
> But quite frankly I was disappointed with what their site
> was showing in terms of enhances in performance. The %
gains
> (if any) were minimal. I found the graphs very superficial
> and didn't show thickness of coating etc and was only done
> for one engine. The graph on the retail is different to
the
> one in 'bulk' and has silly errors.
> I surmise that if the chamber area is 'insulated'
> sufficiently then one could arguably start the diesel
> without glowplugs as the temp rise without losses by
> compression is of the order of 1000 deg F.
>  I aim to show that chamber heat losses can be reduced to
a
> significantly with a thin barrier film.
> The following is some mathematics that I have run through
to
> see the predicted effects:
> Aluminium has a thermal conductivity of 230ish W/mC  (The
> units are a little confusing because its W/(m x m) @1m
> thickness. Different books write it differently [not to
> mention BTU's CHU's Calories etc]. Oops )
> Now most ceramics are of the order of 0.5W/mC
>
> Thus using 'ball park' estimates.
> Losses through piston face might be 230/0.01m is 23,000W
per
> 1sq m of piston face and 1 deg C temp gradient.
> If we were to coat the face to 1mm thickness with a
ceramic.
> 0.5/0.001 or 500W.
> Adding inverses (which is equivalent to adding
capacitances
> in series) we get 489W/mC
> This shows that heat losses can be reduced 46 fold through
a
> 10 mm ally wall.
> If we settle for a 1/ 20 and we know that the bulk of the
30
> % energy loss of an engine, into the coolant is via the
head
> and piston face; (hence the bountiful water cooling in the
> head and the oil squirters aiming at the pistons).
>  The power gains (or fuel economy increase) ought to be
> significant.
> Of the 30% or so heat losses down the exhaust how much do
we
> claw back via the turbo?
> These figures tumbling round my head makes me wonder why
the
> improvements shown by the industrial coatings company are
> somewhat pathetic. Was it Mark Shirley who mentioned SAE
> papers not showing much gain.Can we have more info?
> Mark-The-Miser-UK