Feature request: Fuel flow rate calculated via RPM

[alnavasa]

Hi, I dont have a fuel flow meeter on my diesel engine that has send and return lines and very little consumption, thus making it an expensive device to buy or complex to make

Would it be possible to calculate fuel flow rate via RPMs and a table, EG:

For example for a Volvo Penta D2-75 this would be the consumption, have some input setup similar to the one that's created for tank shaping by adding 5-10 values of RMPS and their corresponding L/h

(Value at prop load)

[alnavasa]

@tkurki

[tkurki]

I think you can achieve this with the help of two plugins: with path mapper you can duplicate the revolutions under another path name and then calibration will allow you to enter a bunch of input-output pairs (like in your table) and calibration will use those to change the input values to match the table with linear interpolation.

[tkurki]

Where do you get this for propeller load? I mean how do I know the table for my boat?

[alnavasa]

I think you can achieve this with the help of two plugins: with path mapper you can duplicate the revolutions under another path name and then calibration will allow you to enter a bunch of input-output pairs (like in your table) and calibration will use those to change the input values to match the table with linear interpolation.

Great I'll give it a try, though I found this to be a very similar case to tank shape modification that the derived data plugin has.

Where do you get this for propeller load? I mean how do I know the table for my boat?

Depends on your engine, Volvo has this charts on every brochure, though if prop is not clean and hull is not clean, it takes more fuel to achieve the desired RPMs or might even not reach them, we can't pass more than 2.200 rpms when hull dirty, and if changed to folding props with two positions might be different, I have stock prop so ti matches closer.

From experience it is approximated since I checked it, (eg: full tank, then 10 hours at xRpms, then refuel => the calculated liters with the chart)

[tkurki]

https://www.cruisersforum.com/forums/f48/fuel-consumption-volvo-29hp-166747.html

[alnavasa]

I think you can achieve this with the help of two plugins: with path mapper you can duplicate the revolutions under another path name and then calibration will allow you to enter a bunch of input-output pairs (like in your table) and calibration will use those to change the input values to match the table with linear interpolation.

Got the values now,
Converted RPMS to hertz and L/H to m3/s

input everything, lets see if it works next time, or maybe I can try a simulate path plugging

D2-75 - Prop load

hertz | RPM | L/h | m3/s

20,0 | 1200 | 2 | 0,000000556
23,3 | 1400 | 2,107 | 0,000000585
26,7 | 1600 | 2,655 | 0,000000738
30,0 | 1800 | 3,737 | 0,000001038
33,3 | 2000 | 4,795 | 0,000001332
36,7 | 2200 | 6,492 | 0,000001803
40,0 | 2400 | 8,077 | 0,000002244
43,3 | 2600 | 10,57 | 0,000002936
46,7 | 2800 | 13,55 | 0,000003764
50,0 | 3000 | 18,27 | 0,000005075

[alnavasa]

Here its for D1-30

[alnavasa]

Looking good. Now to calculate fuel economy is unitless, is this normal? @tkurki Its also unitless

[alnavasa]

The economy, from my math on my excel must be in m/m3,

but its unit less on signalk server, and therefore can't be converted to or milles/L

Is this a bug? maybe is my version.
I am running SK version 1.46.3

[alnavasa]

[tkurki]

https://github.com/SignalK/signalk-server/wiki/FAQ:-Frequently-Asked-Questions#how-to-add-missing-units-and-static-data-eg-displayname

[alnavasa]

https://github.com/SignalK/signalk-server/wiki/FAQ:-Frequently-Asked-Questions#how-to-add-missing-units-and-static-data-eg-displayname

To aces this files.... ¿via ssh?
I am not at the location of the server and I currently access it via Victron proxy, is there any way I can access this files?

[tkurki]

Sorry, metadata management is not yet implemented in the admin UI.

[alnavasa]

Sorry, metadata management is not yet implemented in the admin UI.

Okey,

Thanks!