Why do I want to use a flow meter?

Gasoline Engine:
  Situation 1: Carburator
     Usually there's a fuel pump, electrical most of the times. But it
works always with the same speed. It's fuel flow is constant. All the
excess fuel returns to the tank. So, I cannot use this to measure flow.
In mechanical pumps I don't even have the chance, naturally. There's a
vacuum meter that's related to the fuel usage, but not very accurate.

  Situation 2: Injection
     Like it has been said, I would have to count the injections, and
measure the time each one lasts. It looks feasible. Calibration would be
possible, but difficult without official data. But it could be possible
to obtain this anyway.

Diesel Engine:
  Situation 1: Pressure Injection
     There's no electric relevant parts in most engines circulating. The
pump works with a constant flow. Excess fuel is returned to the tank. I
would have to buid a piezo detector (don't know of any available), but
it's very difficult to measure injection duration.
  Situation 2: Electric Injection
     Still seldom used in my "target cars". No chance of using it.

   So, since my "targeted" vehicles (namely mine!) work with Diesel
Engines, with pressure injectors, the only feasable way I see is with a
fuel flow sensor. Worse than that, TWO sensors. One for infuel, another
for outfuel.
   The bonus with this approach: it's universal! Measure the fuel that
goes out of the tank. Subtract the amount that returns, and voila!
Instaneous (almost) fuel consuption.

  Sorry for the long mail, but it seemed to be necessary a more accurate
description of the situation.

  Thanx for all the answers! I find amazing the amount of experience
contained in this list!

  Bye,
   Nuno.


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  /\/ /  Nuno Filipe Freitas Pedrosa                   __ /..\__/
  \ \/\  mailto:Nuno.Pedrosa@oen.siemens.de           /`'\\__/-\ __
   \/\ \ Tel. : 0049-89-72222342                      \__/  \__//@@\
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