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So I am trying to get real time fuel consumtions data from my Car (2021 Kia Sorento PHEV) via OBD2. I've read up on the topic and it seems to be simple enough.

Fuel Consumtion in Liters per Hour (PID 5E(hex)/94(dec) "Engine fuel rate") divided by Speed in Km/h == Liters/100km.

The problem is: The results are... absurd. When i coast around town @50km/h and the gauge cluster reads an instant fuel consumtion ~3-4 Liters/100km the OBD2 Data suggest an usage of ~17-21 Liters/100km.

I've started to calculate the fuel rate in l/h manually using MAP AFR etc. Data from the OBDII Port and arrive at the same value for Liters/Hour and therefor for the same absurd instant fuel consumtion values.

OBD2 Bluetooth Dongles and popuplar Apps like "Car Scanner" or Torque also report this insanely high instant fuel consumtion.

So I am asking you guys: Is there some alternate formula for fuel consumtion I (And the developers of all those android apps) am not aware of?

Thanks :)

DReffects
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1 Answers1

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Instantaneous consumption can show some "wild" results.

Top Gear's Richard Hammond made reference to this in one series when he pointed out he was getting 99mpg going downhill.

If you want an accurate check of fuel consumption then the most accurate that I know of is to "brim" the tank, drive then "brim" the tank again. You then have distance and fuel consumption.

Solar Mike
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  • Thank you for the suggestion! How does the vehicle itself calculate (the very accurate) fuel consumtion? I would need an average fuel consumtion of the last 1-4 seconds for my project, i doubt that the tank value would be accurate enough... – DReffects Jun 17 '22 at 14:21