MPG - Calculated vs. computer? - Page 2 - GreenHybrid

livvie · #11 (**permalink**) 10-03-2005, 07:08 PM

When the computer's is maxed out at 120mpg, is it averaging in 120 over a period of time or is their an actual number that is not displayed that is averaged in? Seems like, the minute the max is averaged in, the numbers will go off slightly.

tbaleno · #12 (**permalink**) 10-03-2005, 07:23 PM

Could be. However, I would think the computer wouldn't keep averaging the calculations on the display but rather constantly calculate from the total fuel used and miles driven. This way you keep accuracy since the calculation is fresh all the time.

Maybe I should work at keeping my mpg below 120 for a tank to see if the acuracy gets any better.

livvie · #13 (**permalink**) 10-03-2005, 07:28 PM

It seems like 120 is the max that gets factored in, I remember once crusing down a long mountain road and I couldn't get the average to go beyond that.

It also has to do with the sampling rate, if it's a high sampling rate than the average will be closer to real value, if the sampling rate is every minute (i know it's not) the average is going to be way off.

helterskelter683 · #14 (**permalink**) 10-03-2005, 08:55 PM

Quote:

Originally Posted by livvie

When the computer's is maxed out at 120mpg, is it averaging in 120 over a period of time or is their an actual number that is not displayed that is averaged in? Seems like, the minute the max is averaged in, the numbers will go off slightly.

Yeah but it sure makes for a nice real-world surprise when you fill if silly comp thinks you were only pulling down 120 MPG.

laurie · #15 (**permalink**) 10-04-2005, 05:51 AM

Quote:

Originally Posted by laurie

watch out. this will probably jinx me, but i am still holding right below 62MPG with 250 miles on this tank.....

phooey. i filled up this morning, just to compare......manually figured i got 55. what gives? can it be that far off? i went over a really hard "bump" on the road the other day (not enough warning and higher bump than you usually find)....could it have broken something? the car hit really hard

tbaleno · #16 (**permalink**) 10-04-2005, 06:52 AM

I've gotten bad readings like that I always account for about 4mpg lower than the gauge says. were you still at 62? What did the gauge end up at?

laurie · #17 (**permalink**) 10-04-2005, 06:59 AM

Quote:

Originally Posted by tbaleno

I've gotten bad readings like that I always account for about 4mpg lower than the gauge says. were you still at 62? What did the gauge end up at?

the gauge read 60.9.

oh well, i can start fresh today with a 70 mile drive on a 4 lane in the rain....yuk......

clayk · #18 (**permalink**) 10-04-2005, 10:35 AM

Just curious about something. Most of the time my hand calculated average is slightly lower than the computer. Howevr, twice the hand calc'd value was actually a little higher. Anyone else see this happen?

lars-ss · #19 (**permalink**) 10-04-2005, 10:42 AM

Yep - about 25% of the time, my hand calcs have been higher than the FCD, over 16 months of record keeping.

xcel · #20 (**permalink**) 10-04-2005, 11:14 AM

Hi All:

___Some of my previous post is probably bogus. My FCD’s delta creep is due to FAS as the Accord’s TC does not reboot immediately and I lose a few seconds of the recorded fuel consumed on the next acceleration vs. the HCH and Insight’s recording of everything except for a small amount of the coast down during the reboot phase of a FAS or P&G. The FCD’s recording of fuel consumed probably cannot increase or decrease a given amount over time except for fuel pump suction pressure as is being discussed in the other tank full/tank empty thread?

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net