Reverse Cooling patents

[Dave Williams]

-> I lloked thru my Evans file and found some info on the Evans patents
-> for aqueous and non-aqueous ( propylene glycol) cooling systems. The
-> patents for PG systems are: 4,550,694  , 4,630,572   and 5,031,579.

 I went to IBM's patent site and snarfed down the relevant documents.

4,550,694 appears to describe a boiling coolant system using propylene
glycol.  A number of details are mentioned - a circulating pump, a vapor
catch tank and condensor, etc.  There is much discussion of prior art
systems, and frankly I have difficulty understanding what makes the
Evans implementation unique enough to be patentable.

4,630,572 appears to be an extension of 4,550,694.  It is completely
rewritten, but covers much the same ground, adding emphasis on reverse
flow, adding a drawing of a Wankel application, and additional claims
for increased engine efficiency with high temperature operation.
Emphasis is placed on the use of an anhydrous (not containing water)
coolant.

5,031,579, dated July 16 1991 (almost a year after the public
introduction of Chevrolet's LT-1)  uses the small block Chevy as an
example in its drawings.  It again stresses anhydrous coolants, and now
includes provison for a "dehydrator" to remove water from the coolant.

 I can't see any infringements by GM's LT1 engine.  GM has used reverse
flow cooling decades before the earliest of these patents was issued.
GM does not use, and does not recommend use of, propylene glycol
coolants.  The other claims in the patents are not applicable or are
prior art.

 Either there's some other patent Evans is using to justify their
lawsuit, or it's just another nuisance suit, which is why GM maintains a
large and competent legal staff.

==dave.williams at chaos.lrk.ar.us======================================
I've got a secret / I've been hiding / under my skin / | Who are you?
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