Sorry, I accidentally deleted the original message.

Pasi has been asking for a "new" way to measure fuel flow in his car.

OK, so how about this?  A while ago we were discussing a non-invasive fluid
flow measuring technique here on the PICLIST.  The idea was that ultrasonic
sound was injected into a pipe or hose, and upline and downline sensors
measured the intensity of that signal a short distance from the source.  By
comparing the relative intensities from the two pickup sensors, the flow
direction and speed can be accurately determined since sound transfer will
improve in the direction of the flow, and decrease in the opposite
direction.

Even though you are only interested in unidirectional flow, you would still
probably need two pickup sensors since the calculations are done with
relative values, not absolute ones.

Different enough for you?

Martin R. Green
elimar@bigfoot.com