As far as cars are concerned, for quite some time now, most vehicles have
had returnless systems where the pressure regulator and pump are in the
tank. The reason that fuel is not returned to the tank is that the fuel,
having made the trip to the fuel rail and back, has picked up heat. This
heat is released in the fuel tank, heating the fuel and increasing the fuel
tank pressure. This wrecks havoc with the evaporative emission systems
ability to detect leaks smaller than the current spec of 0.020".

Now with an aircraft, this shouldn't be a problem as there are now emission
systems on them...yet.

Dale Alexander


They can run higher fuel pressures and/or increase the injector pulsewidth
as a function of measured or inferred fuel rail temperature. Another
helpful option is to have a system that returns excess fuel back to the
tank which tends to purge out any vapor bubbles.

--
Geoff
The Sea Hawk at Wow Way d0t Com
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