What is Average MPG

[AustinKalb]

I’m assuming it’s a simple running average. Anyone have the details (how many miles or minutes, sample length, those types of things)?

Sponsored

 

[Bucephalus]

Mine averages miles per gallon.

 

[AustinKalb]

Mine averages miles per gallon.

It would seem to me if it used all the miles and gallons since the last reset the mpg would stabilize after a while. Yet it does vary…

 

[Rick_Jame55]

It’s an evil demon that lives in the gauge cluster. It pulls on your soul even when not looking at it. It will anger, depress you If you give into it. It’s better to just squeeze the tall skinny pedal with your right foot. That makes the demon get smaller and go away…..Lol

 

[bd100]

After a long drive at steady highway speed, hundreds of miles, the average does change fairly quickly once you hit suburban stuff. I don't think it's necessarily the average since the last reset, for example.

 

[HorsesRear]

I don't understand anything that was just said here. Where is Hootbro when you need him.

 

[Josh00333]

The built in MPG screen seems to be an average over the last 1k miles. You can reset it, it does track, but even after a reset takes a bit for it to adjust.

I typically reset it after a towing trip.

 

[ShadowsPapa]

It's a running average. It's based on the number of miles driven vs. the fuel used.
Mine is always very accurate.
If you sit at a stop light with the engine running, the average will drop since it is measuring fuel being used but the distance driven is not increasing. Coast down a hill - it will increase, romp it going up a hill, it will decrease.

I am confused about the confusion over it - it's the running average of the miles driven/fuel burned
In other words, how many miles you have gone per gallon.

It measures fuel use just like the devices Myth Busters used to measure fuel used during their drives to test various driving methods and truck accessories.

It IS the average since the last reset. It starts out using your last fuel needs - reset it with engine running and it might pop right up with 15 even though you are not moving, but once it gets going, it adjusts to reality.

I have used FillUp on my phone to compare to the cluster readings and over 2 or 3 tanks, the total average of all tanks and the average of the cluster numbers match up.

 

[pharmfrank]

I believe my gas averages are fairly consistent and only vary significantly when I switch back and
forth from my 'winter' all terrain tires to my 3 season all-weather tires. What I do believe is inaccurate is the gas gauge, the 'needle' and the actual pump fill-up can be as much as 5 gal
difference. Since I have a long history of inaccurate gas gauges, beginning with my first car,
a 1956 Olds Super 88, when the gauge indicates just below half tank I think about filling-up.
The first chance I have of a long highway trip I bring along a few gallons of gas in an approved
container and run the vehicle until it tells me nearly empty, or the needle is bouncing on 'E' .
Over the years some vehicles have taken me more than 30 additional miles on 'E' while others
sputter before. I doubt electric vehicles will do better. So with that much variation in information
how accurate can the 'averages' be, just a guideline to me.

 

[AustinKalb]

My question was fairly technical.

Is it the last 10 miles devided by the fuel used during those miles. Or maybe it’s the last mile. Or maybe since the last reset (unlikely, since then a couple miles of high or low mileage wouldn’t hardly budge the gauge).

Does it use flow and integrate over time? Or maybe just fuel tank level to estimate usage. Flow rate is pretty easy to measure so I’m guessing it must be integrating, then for how long per sample?

Anyone see where I’m going with this?

 

[ShadowsPapa]

My question was fairly technical.

Is it the last 10 miles devided by the fuel used during those miles. Or maybe it’s the last mile. Or maybe since the last reset (unlikely, since then a couple miles of high or low mileage wouldn’t hardly budge the gauge).

Does it use flow and integrate over time? Or maybe just fuel tank level to estimate usage. Flow rate is pretty easy to measure so I’m guessing it must be integrating, then for how long per sample?

Anyone see where I’m going with this?

Average over the tank. Not just the last few miles. You can tell by the way that you can easily impact that number in the first 100 miles, but as you add miles to that tank, it takes a lot more to impact that average number. It's like any other average - if you have driven 50 miles, what you do can cause wild swings in that number. If you have gone 200 miles on that tank, since reset, then doing those same things has much less of an impact because it's taking 200 miles into account, not just 50.
So it's a RUNNING average. Not the last 10 or the last 40 or the last 100 - it's since the last RESET of the display.
It's not going by the gauge at all - that can change with how you park, going around corners, going up a hill or down a hill. It's measuring actual fuel used, not what's in the tank.

It's a simple process - constant watch over the fuel being used vs. miles driven since you last reset it.
It's not a sample - there's no sample size. It's not based on anything but the fuel being used vs. the miles you have driven.
And the longer you go without resetting it, the more it takes to bring that average up or down because it's spread over more miles.

I suspect you are overthinking it.
It's a constant thing once you get driving after a reset.
Fuel used vs. actual miles driven. Again, stop and let it idle and watch that average go down. Light pedal it and you can raise it.
Miles REMAINING - that's a different animal - it's based on "guesstimate" of fuel in the tank vs. your recent driving habits. I can change that number very easily by acting like I was 14, or acting like my life depended on my getting a better number. That one will change and is based on current conditions and what it believes is in the tank.

My wife has watched that average mpg number for years - she had multiple Grand Cherokees before her current Wrangler and was always trying to get that average up.

 

[Alx63]

I’m assuming it’s a simple running average. Anyone have the details (how many miles or minutes, sample length, those types of things)?

On short trips around it's 16.9, Daily work freeway trip 17.6 with moderate traffic, long trips open highway 18.03 my best. From Katy to north of San Antonio.

 

[ShadowsPapa]

Over the entire tank full - verified by FillUp app - this was a totally stock Overland.
Since it matched the math by app and hand - it means it's the average over the entire tank - NOT a sample or snapshot in time.

 

[bd100]

The reported average does appear to change fairly quickly when suddenly changing between highway and stop/go. I.e. Reset the counter, then do a 1000 mile drive on the highway across the country, then a day in local traffic.

 

[ShadowsPapa]

The reported average does appear to change fairly quickly when suddenly changing between highway and stop/go. I.e. Reset the counter, then do a 1000 mile drive on the highway across the country, then a day in local traffic.

Yeah, it's since last reset, but I say tank because I reset it at each fill to check each tank full. Basically it's from the last reset.
So if you reset it when you fill the tank, it's for that tank.

Sponsored