BTW If a way could be found to idle a gasoline engine with
   a wide open throttle (like a diesel engine) the pumping loses
   could be drastically reduced as would the idle fuel consumption.

   The other thing that strikes me about this carb design
   is its analog computer nature. It has infinite resolution.
   None of this stair step analog to digital converter stuff.

   If all works as it should the spring will stay deflected
   at it's max deflection and the sum of the spring force (about 60 pounds)
   and the intake manifold vacuum pneumatic force on the back side of
   the diaphragm should equal the force on the front side of the
   diaphragm due to fuel chamber pressure supplied by the high
   pressure fuel pump. The forward spring force and the pneumatic
   back force on the diaphragm remain in balance. As the intake
   manifold absolute
   pressure increases reducing the pneumatic force on the back side of
   the diaphragm the spring force increases.

Wow Paul,
I haven't been able to keep up with the calculations as I've been
repairing my truck. The force you're quoting just seems too high though.
I'll try to go thru the backlog. Most diaphragm carbs I've seen have
VERY light springs. I would estimate that the spring force rarely
exceeds about 5-10 pounds fully compressed. If you are running a really
big diaphragm diameter it could change things. Most are about 1 inch in
diameter.
The answer to the first snipped comment is direct injection. I've seen
it in action too. Mercury outboard runs it in both the 2 and 4 cycle
versions of their engines in their engine test lab in Australia. The 2
cycles sound truly weird, as they never miss like we are used to. They
sound like they are screaming along at idle, when in reality they are
running 1000 RPM! Siemens new piezo system may come to our rescue there.
The system is used on both common rail diesels and gasoline engines.
Audi is running it and VW of course so they may bring the cost of
components down to a reasonable level. The Orbital stuff on the Mercs is
just too expensive to experiment with.
Bill Jepson




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