TOM PITTENDREIGH wrote:

I've read a lot of messages and seen a lot of beautiful color diagrams all
on this problem of returning unused [presurized] fuel from the injector fuel
rail to the supply tank(s). IMHO folks are missing some of the basic laws of
fluid dynamics or even simple "seat of the pants" hydraulics. This higher
pressured fuel can be returned to the supply side of the fuel system at any
place the pressure is lower than what it is at the "overflow" side of the
fuel rail relief valve. This means that you can "tee" it back into the
supply hose right at the input side of the fuel pump. It doesn't have to be
piped all the way back to the tank(s) and "poured" back in.

I think you are forgetting about the excess heat in the return fuel Tom.
You don't want it right at the intake of the pump as the fuel supply could
get hotter and the pump vapor lock. Also for vapor lock reasons one would
like to have the pump buried in the fuel tank.

Paul Lamar

Paul,

  No offense against Mr. Pittendreigh, but how can we best deal with
the problem of rehashing the same things over and over again as new guys
come on line?  Read the CD, I guess, but is this the best way?  How about
some std commentary after the discussion has settled out.  For instance,
I think that there is substantial concern about recirculating fuel in a tight
loop, so most probably at least want to go back to a header tank or
(safer, IMHO) to one of the tanks.  Even which tank is an issue, depends
on whether you want to make a bit of pilot workload and same money
and complexity of the fuel valve (weight, too) or keep it ultra simple,
(idiot resistant?) but spend more money, time and weight.

Bill

Write up some fuel system does and don'ts Bill and we will post them on here for comments
and then on the ACRE Newsletter web site.

Paul Lamar
 
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