The interesting discussion on turbulence and fluid flow theory involving
the efficiency of radiator cooling systems has reminded me of a problem
I encountered during my fuel injection system design for my TR-6.
Initially when I started the design of my fuel injection system for my
TR-6 I wanted as much airflow as possible into the engine as possible.
My thinking was that the more air you can punch into the engine the more
HP's you can get out. Well, air is important but what is more important
is the air/fuel mixture. The better the fuel is mixed with the air
intake the more efficiently the fuel is burnt and hence the more HP one
can gain from each piston stroke. The first iteration of my design worked
fine at partial to full throttle positions but my low end drivability
was awful and idle emission readings indicated that HC outputs were
way too high. At this point I decided to scrap the idea because the
project was starting to get expensive! But then after using a Colortune
spark plug I noticed that many if not all of the cylinders were running
too lean at idle? How can this make the HC's too high? Well the mixture
evidently was too lean to burn but definately rich enough to peg the emissions
tester I was renting time on from a local garage.
The lesson learned here was that I needed wonder beautiful wisps of
turbulence at idle and partial throttle openings and then a more laminar
flow at high rpms and wide open throttle. I may not be telling a lot
of you anything new here but when you look at a Stromberg or SU it is
so wonderfully restrictive at closed throttle. The air has such a
small area to pass that is has to do it at very high speeds thus picking
up those fuel molecules and mixing them into a fine burnable mix.
The point I'm making here is that both turbulence and perfect laminar flow
are good things it is just a question of what it is YOU want physics
to do for you. Sometimes one has to look at the equations but follow
what really works. Engineering is a tight rope walk between mathematics
and the real world. If it doesn't work in the real world it isn't
worth very much.........as far as an Engineer is concerned!
Mark deHaas
dehaasm@napc-1.navy.mil
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