Not a terribly important question, but I haven’t been able to come up with the pattern for MPGe increase/ decrease. Why does it increase/ decrease .2 sometimes and .3 other times?
Thanks for the reply. I’m sure that all these factors affect the efficiency, but it appears the numbers are pre-set. If, for example my MPGe increases by a certain amount ( e.g. 79.7 to 80.0 or 80.9 to 81.1) and I then drive using gas, the decrease will always be to the previous number. The car wouldn’t go from 79.7 to 80.0 and then drop to 79.8. Nor would it decrease from 81.1 to 80.8. This math teacher has to figure out the pattern or just realize the numbers were randomly set.Not a terribly important question, but I haven’t been able to come up with the pattern for MPGe increase/ decrease. Why does it increase/ decrease .2 sometimes and .3 other times?
There's a per-charge MPGe reading on the Gen 2 Energy Usage display. I figured that's what was under discussion as it's the easiest thing to have presented and notice changing. Not my photo, but...Not sure what gauge you’re looking at to watch the MPGe increase/decrease as you drive on battery and then on gas, but that sounds like a "combined," or "lifetime" MPGe reading for a Gen 2 Volt.
Thanks for that photo. I note the 122 Combined and 108 Lifetime MPGe numbers are three digit numbers, i.e., whole numbers only (no decimal place). I do have some screen shots in my notes showing similar energy usage displays with Combined and Lifetime MPGe numbers lower than 100, and they do include a single decimal place, such as 81.2 MPGe. It’s difficult to know how precise some of the Volt’s displayed numbers are unless you see it.There's a per-charge MPGe reading on the Gen 2 Energy Usage display. I figured that's what was under discussion as it's the easiest thing to have presented and notice changing. Not my photo, but...
The kWh Used on the energy usage display screen may be an "estimate" (actually, a net estimate of grid power used less regen put back into the battery), but MPGe numbers, based on data a bit more precise than the displayed numbers, are math calculations, not "estimates."That’s correct. This screen ( 108 MPGe) Lifetime, however, presents the ideal driving conditions. One of my nephews responding to a perceived change in my driving, said that I didn’t use to drive like a Grandpa. My 2017 Volt ( approx 26 K) shows 81.1 Lifetime. In the summer, I do get more than 50 mpg in gas mode. No one who lives in Portland, Maine and drives in cold weather could ever achieve this unless he/she swore off ever using gas. After all the analysis, my guess is that an engineer at GM set the numbers in .2 or .3 increments without any plan. These are, after all, estimates. Oh… the curse of having the mathematical mind and looking for numerical patterns in everything!
Keep in mind that MPGe is not tracking the increase or decrease of quantities that can be measured in units or tenths of units (e.g., miles, fuel consumed). MPGe is tracking the ratio of the sum of two units (ev + gas miles) divided by the sum of two units (ev Ge + gas Ge).I've likewise noticed that my lifetime MPGe numbers are displayed to the tenths digit but only move in increments of 0.2, not 0.1.