How does the fuel economy work ?

[tomille3]

Hi
can you explain me how does the fuel economy works ?
i have 1 GPS , 2 x 4" SMIS gauge + 1x 2" SMIS gauge

How is it doing the calculation ?

thks

[artdf175]

Maybe a little more information ?
What engine model year
Engine connected to electonics via a engine interface cable?
Some added details will help in narrowing down the best answer to your inquiry

[Moonlighter]

I won't get highly technical on this, but......

The basic concept is that the engine's ECU pulses the injectors which causes a known amount of fuel to be injected into the cylinder. Thus a fuel flow rate can be determined by the interface cable applying a formula embedded in its software using the amount of fuel injected through each injector over time - eg per second which is able to be extrapolated out by the formula to litres/hour or gallons per hour etc.

Now, gph or lph is a measure of "fuel efficiency", it is not a measure of "fuel economy". To get fuel economy you have to add the distance factor.

Also, through applying a further formula embedded in the interface cable, it simply calculates actual fuel used since the system was last reset.

The fuel economy calculation is then done by the MFD (gps/sounder combo or SMIS display) that is attached to the network, this time the calculation is not done by the Suzuki interface.

The MFD takes the fuel flow rate being passed to it over the NMEA2000 network by the interface, and the ground speed as measured by its inbuilt GPS or a separate GPS antenna that is attached to the network.

It uses these data items to calculate distance being travelled at any instant, and then divides that by the volume of fuel being used, to calculate mpg or km/liter or whatever form you want to use for fuel economy.

Thus, you get the display showing you instantaneous fuel economy figures, and this allows you to adjust speed and trim angles to achieve the best possible fuel economy in the prevailing conditions.

Clever stuff, but quite simple in concept.

Hope that answers your question!

[boashna]

gps says we moved 1 mile and fuel flow says we used one gallon so we are getting one mile per gallon

[tomille3]

Thank you Moonlighter

[tomille3]

Maybe a little more information ?
What engine model year
Engine connected to electonics via a engine interface cable?
Some added details will help in narrowing down the best answer to your inquiry

Suzuki DF 150 Lean burn 2014
Yes connected to NMEA with interface

[Antares580]

Lean Burn

CUTTING EDGE Technologies : MARINE | GLOBAL SUZUKI

[tomille3]

Antares580
I was talking about the fuel economy source on the SMIS gauge menu , I wanted to know it was working......

Anyway thanks for your documentation it is very interesting , even if I didn't see change between my old DF150 and my new DF150 lean burn ....But I'll do another post for that

[tomille3]

I won't get highly technical on this, but......

The basic concept is that the engine's ECU pulses the injectors which causes a known amount of fuel to be injected into the cylinder. Thus a fuel flow rate can be determined by the interface cable applying a formula embedded in its software using the amount of fuel injected through each injector over time - eg per second which is able to be extrapolated out by the formula to litres/hour or gallons per hour etc.

Now, gph or lph is a measure of "fuel efficiency", it is not a measure of "fuel economy". To get fuel economy you have to add the distance factor.

Also, through applying a further formula embedded in the interface cable, it simply calculates actual fuel used since the system was last reset.

The fuel economy calculation is then done by the MFD (gps/sounder combo or SMIS display) that is attached to the network, this time the calculation is not done by the Suzuki interface.

The MFD takes the fuel flow rate being passed to it over the NMEA2000 network by the interface, and the ground speed as measured by its inbuilt GPS or a separate GPS antenna that is attached to the network.

It uses these data items to calculate distance being travelled at any instant, and then divides that by the volume of fuel being used, to calculate mpg or km/liter or whatever form you want to use for fuel economy.

Thus, you get the display showing you instantaneous fuel economy figures, and this allows you to adjust speed and trim angles to achieve the best possible fuel economy in the prevailing conditions.

Clever stuff, but quite simple in concept.

Hope that answers your question!

one more think ...
As I have 2 SMIS 4" gauges and Lowrance HDS10 gen2
It means I have nothing to do ...

I just have to go on the SMIS Gauge , on "fuel Economy" and then everything will be done automaticly, the calculation will be done by the devices and the gauge will display the fuel economy ?
that's correct ?

[Moonlighter]

Yes.

The only thing you might want to do is customise the pages on the SMIS displays to show the fuel economy info in the position or on the page where you want it.p - but that is up to you. The SMIS will take GPS data like speed from the HDS and use it to calculate fuel economy.