WATER INJECTION...(was Holden...etc.)

[Raymond C Drouillard]

On Sun, 3 May 1998 11:59:15 +1000 (EST) danny_tb at postoffice.utas.edu.au
(Danny Barrett) writes:
>G'Day again...
>I've just finished with the rest of my email, so I can give a better
answer
>to the one I just ave a few minutes ago... This email is partially
directed
>to Ray, and partially directed to others. Note that although I may seem
to
>have quite a few answers, I have MANY more questions than answers, and I
am
>by no means an expert on this topic...

You're more of an expert than I am.  You, at least, have tried it.  The
motto at Lawrence Technological University (my Alma Mater) is "Theory and
Practice".

Anyhow, I'm all for increasing the economy of my engine.  I drive a 1989
Jeep Grand Wagoneer powered by a 360 CID V8 (AMC, not Chrysler).  It
drinks fuel, so a 20% increase like you have experienced would be well
worthwhile.

I have already screpped the carburater and added Holley Pro-Jection.  I
am working on modifying the ignition system so that I can use the spark
control that is available with the Holley box.  After that, I'll add a
knock sensor.  My next scheme will be to build one of those wide-range O2
sensors and feed the signal into the ECM in place of the origional O2
sensor.  I can then modify the table that allows you to choose the O2
voltage that feedback system tries to track.  That way, I can program it
to run way lean during cruise and rich at low vacuum.

This water injection idea is interesting, and looks promising.  If the
ideal injected amount is proportional to the amount of fuel injected, I
can simply use the injecter signal.  If it also depends on the manifold
absolute pressure, I will need to take that into account.

If steam is injected and it does, in fact, recondense at TDC, that heat
will be given up there and will increase the temperature of the
compressed air/fuel mixture.  Once the mixture ignites and the piston
starts to drop, the heat will be reabsorbed as the liquid droplets flash
into steam.  Now, it's beginning to look like something that recycles
waste heat from the exhaust.  That sounds way out there, so I'll have to
give it some thought.

Back to practice vs. theory.  The experimental data seems to indicate
increased efficiency when the proper amount of water is injected.  We
need to come up with a plausable theory to explain it.  Also, we need to
reproduce the results of the experiment.

My origional thought on using water injection was to increase the
compression enough to need higher octane gas, and to use the water
injection as an antiknock agent.  That way, I could run high compression
with cheap gas.  Water would, in that case, only need to be injected when
the throttle is opened wide.

By the way, please don't get the idea that all of my mods are strictly
for better fuel economy.  I could buy a LOT of fuel with the money that I
have sunk into that vehicle.  What I really like (don't tell my wife) is
the extra power and drivability.  If all I wanted was better economy, I
would stick a six-banger in it.

Ray Drouillard


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