Russell Kent wrote:

Jeff Spitzer replied to Ed's fuel sump arrangement:

How much current does your fuel pump draw Ed?  At idle nearly 100% of that
energy is going into heating the circulating fuel.  There is also
considersable heat picked up from the engine compartment and fuel rail.  A
simple calculation will tell how long you can idle until the fuel boils.

Jeff,
I agree, although I can think of two mitigating actions one can take:
1. Put a fuel cooler between the pressure regulator and the sump.  Of course,
doing so adds yet another "radiator" to the engine.  The fuel cooler would need
to be far away from the heat of the engine and exhaust manifold, since it is
trying to keep the fuel much coler than we tolerate water or oil.

2. Reduce the fuel pump power under low-demand circumstances.  Ideally, the fuel
injection computer would control this.  Perhaps Tracy could comment on the
feasibility of a frequency-controlled (i.e. tied to RPM) power source from the
EC2 to the fuel pump power rail?

Russell Kent

 
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