In a previous blog about the ULPower engine in the 650 there was a discussion about fuel use.  Since these engines use fuel to cool the injectors and send the excess fuel by return line back to the tanks I was wondering how the GPH fuel use is determined. Seems that a fuel flow sensor in the line to the engine would not give a correct reading.  Just wondered how it was done.

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Comment by Andrzej Kostkiewicz on November 9, 2011 at 3:15am


Yes one flow sensor give You wrong reading . You need flow COMP with two flow sensor In and return I.E MGL Avionics ., Or You should to make a small header tank ( 2 liters ) in fuel  line . Fuel from engine come back to small tank for time to cool and from this tank High Presure pomp for inejctions system suck fuel . Flow sensor is connectet before header tank after fuel selector  . I do this in my BMW in my 601xl and its working , Other option is connecting Bosch EMS with MGL flow comp by wire from EMS  , This option is given by last Flow Comp from MGL avionics it givs perfect accurancy !  . Look for manual from MGL .


Comment by Ben Haas on November 7, 2011 at 2:55pm
Fuel injected engines that use the fuel return to the tanks have two fuel flow transducers,, one measures the incoming fuel and the other measures the returning fuel... Then the Fuel flow gauge/ computer does the math and gives an accurate GPH reading...
Comment by Peter Sonders on November 7, 2011 at 2:45pm
To get an accurate fuel flow on a fuel injected engine you need a engine monitor that can interpolate the injector pulse as fuel flow. I don't know if the UL Power engine ECU has a "pulse" output connection to a EIS/EMS...
Comment by Caleb Gebhardt on November 7, 2011 at 9:57am
There is a second fuel flow sensor that has to be installed on the return line. In our 650 demo aircraft we have multiple fuel flow sensors hooked up to the Dynon Skyview. It takes the readings from the supply line and subtracts the readings from the return line and displays the results, which is the actual amount of fuel being burned per hour. If you are using different instruments you will have to check into how this is handled on your system but the Dynon Skyview is very simple to set up.
Comment by Andre Levesque on November 7, 2011 at 6:46am

Good point Joe !!  but I'm not sure how much it impacts the fuel consumption reading.


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