Misc Electronics / barrier coat / reverse cool.

[Robert Harris]

Not really.  Lets look at what happens.

Combustion - Third Edition.  Irvin Glassman - page  96

(1) Following ignition, the primary fuel disappears with little or no energy
release and produces unsaturated hydrocarbons and hydrogen.  A little of the
hydrogen is concurrently oxidized to water.

(2) Subsequently, the unsaturated compounds are further oxidized to carbon
monoxide and water. Simultaneously, the hydrogen present and formed is
oxidized to water.

(3) Finally, the large amounts of carbon monoxide formed are oxidized to
carbon dioxide and most of the heat released from the overall reaction is
obtained. Recall that the CO is not oxidized to CO2 until most of the fuel is
consumed owing to the rapidity which the OH reacts  with the fuel compared to
its reaction with CO."


Then one must note from the above or other references that the carbon monoxide
to carbon dioxide reaction where most of the heat of combustion occurs
essentially "freezes" around 700 c.  The longer the combustion remains above
700c, the more of the fuel that will be converted and the more heat that will
be released.  Or another way to put it, when the temperature of the combustive
gas drops below 700c, we essentially stop generating more heat (pressure) and
live with what you have.  

Of course the reaction still goes on - but at up to orders of magnitude slower
rate.  

Coating's reduce the heat loss "cooling" at the critical time around TDC, thus
allowing more heat to be released in combustion and greater pressure to be
made.  Note that the heat increase in not from the heat being returned to the
gas by reducing the loss - but from more CO completing to CO2 and thereby
releasing more total heat.

The majority of "cooling" occurs as the gas expansion transfers energy from
the combustion gases to the piston.  Since the face of the exhaust valve is
significantly cooler, LESS coolant is needed in the heads and more might be
required in the block - thus negating any advantage of reverse cooling.

Previously he stated 
"and the fuel is consumed, to a major extent, before significant energy
release occurs.  The higher the initial temperature, the greater the energy
release, as the fuel is being converted"  

Ceramic coating everything nicely increases the initial temperatures also by
reducing heat rejection to the chamber.

This increase in ability to convert fuel to energy is at the heart of the air
pollution war - as it after a certain temperature begins to dis-associate
nitrogen and form nitrous oxide products as well.  

Also to note - this book is primarily about combustion and it processes and
most decidedly is not concerned with the otto cycle and carnot worship.


>
>Date: Wed, 12 May 1999 19:56:40 -0400
>From: "Bruce Plecan" <nacelp at bright.net>
>Subject: Re: Misc Electronics / barrier coat / reverse cool.
>
>Just for grins, we barrier coat the piston domes
>the intake valve face, the exhaust valve face.
>In theory then we have captured more heat to be recovered by the movement of
>the piston, right??.
>Now that we have with held this higher heat, for a longer period of time,
>then more
>heat is put into the top of the cylinder bores, right.....
>  The cooling system was designed so that the exhaust valve seat area is the
>"hot spot",  so don't we now have to "reverse" cool the engine to get the
>max effectiveness out of this??..
>grumpy
>


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