Dave,
In current return systems, returning the fuel
from the fuel rail alone to a header tank is a NO! NO!
The residual heat in a small fuel tank isn't
sufficient to cool the fuel before it goes back into the fuel rail - it causes
vapour lock.
All return fuel, I have been told , must return
to the much larger tanks to dissipate the heat
The Wankel Rotary which has fuel cooling the
rotors is suspect in this regard. I have no facts on this, only what has been
discussed on other sites.
Given this information I believe you may have a
considerable problem with heat.
George ( down under)
Sent: Monday, February 07, 2005 3:46
PM
Subject: [FlyRotary] Heating the
Fuel
In
anticipation of the new turbo, I am considering ways to improve coolant
cooling. Besides the obvious more air, more ducting, more radiator; I
have been again toying with the idea of a heat exchanger. This time
coolant to fuel. The plan would be to use a typical oil/water
exchanger but use fuel instead of oil. I would use the fuel on the way
back to the tank, and the coolant after it has already been cooled by the
radiator. The fuel would then go back to the nice metal tank of the
RV.
I
am looking for input on the implications of heating the fuel. I expect
it would reach max temps of about 190 (usually a
little cooler) but quickly cool once in the tank. Can the
fuel tolerate that temp without vaporizing? It will probably expand in
the tank but I don't expect that will occur faster than it is used up.
I have no guess as to what temp will become steady state for the fuel pumped
out of the tank. My guess is that it will not be much warmer than
normal, but a slight increase in temp may help with
vaporization.
The last question is how much will it cool the coolant. My hope
is about 10 deg but I doubt it will be quite that much. I know others
have considered using the fuel to cool (Tracy) and I would appreciate your
thoughts.
Dave Leonard