How does the Telluride estimate the miles you'll get in a tank of gas?

[tib2d2]

everytime I fill up the tank, I'm given a different "miles remaining in tank" number. How does the car determine the miles left?

 

[Semator20]

Magic.

 

[Tellmeyourride]

everytime I fill up the tank, I'm given a different "miles remaining in tank" number. How does the car determine the miles left?

You may be "topping off" differently each time. I suspect this is the biggest factor you are seeing. The filler pipe holds a lot of gas.

The following is from research.
True, gasoline does expand and contract a little depending on its temperature. But filling stations store their gasoline in underground tanks, where the temperature variation during the day is much less than in the air above. The result is that the temperature of the gasoline coming out of the fuel nozzle varies very little, if at all, during any 24-hour stretch at any particular station. However, once the gas is in your car, and has been there a while, notable changes in volume can take place. The volume of liquid fuel expands and contracts with changes in temperature — quite a bit, actually — more than four times temperature's influence on water volume. Gasoline's volume changes approximately 1 percent for every 15-degree temperature change, according to the U.S. Government Accounting Office.

 

[Semator20]

Once the gas nozzle clicks off, I stop.

 

[jbruesewitz]

No need to overthink this. Miles to empty = amount of gas remaining x your recent fuel economy. Plus there’s a little buffer since 0 miles to empty is not completely empty.

If you’ve been primarily driving in the city recently, you’ll fill up and see a relatively low number. If you’re on a long highway-only road trip and fill up, you’ll see a relatively high number. That is all.

 

[rcoplien]

I'm pretty sure it also take your average MPG that you had before fill up and takes that against the fill up.

 

[jinda]

Pretty sure it's not related to volume expansion.
It's probably more on what is your most recent average MPG.
The system uses that MPG to compute the estimated miles depending on how much gas left you have in the tank.

Ex. If you have 18 gallons in the tank and your latest average MPG was 18 mpg. Then your estimated miles could be 18 miles/gal x 18 gal = 324 miles.
The reason why your miles fluctuates is because you get different MPG depending on how you drive.