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Hi,

In the operators manual, fuel flow tables and dats are presented. A manufacturer told me that this is not fuel consumption. What is the difference, if there is one?

Thanks for any thought.

Ran

  • Re: Fuel flow vs fuel consumption

    by » one year ago


    If it is the table I am thinking off with many cells and columns then it is fuel consumption.

    This is what is known as a "look up table" the ECU finds the nearest match, temp, rpm,throttle, inlet temp, inlet pressure rpm OAT altitude, EGT  etc then from the table chooses the "correct" amount of fuel to inject...actually the fuel injector open time.

    The manufacturer has spent many hours developing and tuning this table

    Fuel flow through the system ie from the pump/s must always be higher than the actual fuel used to maintain a margin and correct fuel pressure.

    I recently completed a "fuel flow" test of the fuel system (Tank to pumps through fuel filter to fuel rail etc) on a 915, this was about 180 L/hr  far higher than any fuel consumption ....as is should be

     

     


  • Re: Fuel flow vs fuel consumption

    by » one year ago


    Thanks, Ran


  • Re: Fuel flow vs fuel consumption

    by » one year ago


    Just an FYI
    with the 915iS and the 912iS, The only way to get "true fuel flow indication" is to place a fuel flow transducer on the inlet side of the fuel system and one on the return side. The ECU stated fuel flow (shown on the panel) is only a "calculated value" and is approximately 11% inaccurate (on the low side). Meaning the engine is using more fuel than what is displayed.


  • Re: Fuel flow vs fuel consumption

    by » one year ago


    For current fuel flow (instantaneous LPH or GPH), that's correct, at least for Dynon systems.  However, the calculated fuel used (and therefore fuel remaining) can be corrected to very near actual.  The Dynon installation manual says the following (page 7-37):

    "If you have not installed physical fuel flow sensors (Dynon Avionics P/N 100403-003; Electronics International FT-60 “Red Cube”), the fuel flow information from 912 iS ECU used by the SkyView Fuel Computer can be adjusted if necessary: SETUP MENU > HARDWARE CALIBRATION > EMS CALIBRATION > FUEL FLOW CALIBRATION > PUL/GAL (C37 P14) > (value). The default value is 68000. Higher numbers will reduce reported fuel flow; lower numbers will increase reported fuel flow. For example, if the reported fuel flow is 10% low (determined by careful records of fuel fills and fuel used), set the value of C37 P14 to 61818 (68000 – 10%). Changing this value will not alter the displayed fuel flow; it will only alter the fuel used calculated by the SkyView Fuel Computer."

    I'm pretty sure Garmin and others offer similar functionality.


    Thank you said by: Joe

  • Re: Fuel flow vs fuel consumption

    by » 6 months ago


    Rotax-Owner wrote:

    Just an FYI
    with the 915iS and the 912iS, The only way to get "true fuel flow indication" is to place a fuel flow transducer on the inlet side of the fuel system and one on the return side. The ECU stated fuel flow (shown on the panel) is only a "calculated value" and is approximately 11% inaccurate (on the low side). Meaning the engine is using more fuel than what is displayed.

    One question: WHY??? Why in the world would an engine manufacturer have their ECU report, not only inaccurate fuel flow, but inaccurate on the unsafe side??? This is ridiculous. Rotax needs to fix this. 


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