Thanks. I’m not new at all this. I just expected better. I’ll delve into it.
I was going to make a similar comment. Because MPG is a non-linear scale, a difference that seems major in a high-MPG car really isn’t so major. It would have been more natural and intuitive to use GPM (or GP100M) instead, similar to what’s done in metric countries.
This article has a pretty good example of this concept:
https://www.edmunds.com/car-reviews/features/mpg-is-stupid.html
If you think in percentages it doesn’t matter what metric you use.
Ten vs 12 mpg is the same as 40 vs 48 mpg.
Although I can see math pedestrians focusing on a numerical difference of 8 vs 2.
Agreed.
The original poster’s dilemma remains the same; why is this car getting 13% worse mileage than EPA from a model that often delivers better than EPA? While not a huge difference in operational cost it might signify problems that will affect the car in other ways. If running rich it will reduce the catalytic converter’s life and may dilute the oil resulting in increased wear. Tight pistons, or poor finishes on sliding surfaces could lead to increased wear, increased oil consumption and further inefficiencies. A motor with improperly magnetized rotor would be less effective, etc. On the other hand if the computer is merely setting traction battery usage on the low side but the engine is running efficiently, the (expensive) battery might last longer before replacement (pure speculation).
This car has a dash page that tallies the percentage of time the car has operated on battery alone, a low figure might suggest something to a mechanic.
Discussion Alert!
November 4
ken2116:
While you’re seeing a 13% difference in mileage (46mpg vs. the combined EPA 52mpg), in absolute consumption terms this is 0.25 gal/100 miles, so the inefficiencies responsible are relatively small and may be difficult to identify.
I was going to make a similar comment. Because MPG is a non-linear scale, a difference that seems major in a high-MPG car really isn’t so major. It would have been more natural and intuitive to use GPM (or GP100M or GP1000M) instead, similar to what’s done in metric countries.
When I see that, I focus on measurement accuracy…
Hybrids are much more sensitive to small changes. My hybrid get 44 mpg going to work, 36 coming back, all because of a very gentle downhill.
If the comparison is of any use to you or your mechanic, at ~ 4600 mi. total our dashboard display indicates 62.3mpg (about 61 actual), 25 average mph, 41.1 % in EV mode. It’s occurred that ours is running in EV mode too much, at the expense of battery life, but who knows? We’ve also observed that from a cold start our average for the trip will loiter in the low 50’s for several miles before zipping up into the low 60’s after ~ 12mi. (typically 25 min.) of mixed city and freeway driving - this might be an indication of when the oil has fully warmed up. Good luck with this and it would be interesting to hear how it’s resolved.
I notice on cold starts the MPG starts out lower then works it way higher. We are going to start recording our fill ups and odometer readings to check the system. In another month we will be due for the 5000 check up so I will bring the issue to the attention of the dealership. thanks for your input.