Understanding MPG computations

[dirty hippie]

It's been almost two months of Insight ownership for me and I feel like I'm still learning how the Insight works. Today as I was driving to work it occurred to me that when I reset, say, the segment read-out, I feel like the mpg reads higher and changes often. However, the Trip A/B read-out, which is not reset and shows cummulative miles, has small incremental MPG changes. Today I decided to view Trip B, which I didn't reset and had about 70 cummulative miles from five separate trips. The mpg stayed at a constant 53.x mpg (city driving, CVT). Normally when I do a reset of the segment, the mpg will read a bit higher at the end of the trip.

Btw, when starting the car at --mpg, the sequence seems to be: 6.7, 25.1, 39, 41, 53, 54.2, 56.1, 59, 61, 65, etc.

It seems there are big jumps eary on and then the changes become more linear until it remains steady with small changes.

[satchel]

Cold engine, warm engine and average over greater distance. It's all relative.

[faxe]

Bigger jumps early on the trip, as the display updates in 1 minute steps.

[nayrhyno]

This is just averaging at work. It updates at specific time intervals and tells you the average MPG over the previous XX.X miles at that time when it updates.

When your trip meter has already 500 miles on it, you will not be able to alter the MPG readout with only the most recent 2 miles or whatever happened since the last display update. When you reset and get 75 MPG over the first 2 miles, and then update after 2 miles at 50mpg, it will read 62.5 mpg.

It is as simple as that.

I often predict what I shoul dbe able to get my MPG to over a short segment. Say I have 500 miles on my TRIP A and 60 MPG. I know I will be driving 50 miles on an upcoming segment so if I manage a 10% higher mpg over that segment, I will get a 1% jump in the TRIP A reading.