>>
>>> Well, my 92K mile experience would differ. While there are
>>> variabilities in individual fillups, over the span of 3 years where I
>>> logged each of 203 fillups and the number of miles between them and
>>> found that the MPG display in the Prius was 5.21% higher than the
>>> calculated MPG. It was pretty consistent; a few times higher and a few
>>> times lower. I have to believe that over 203 tankfulls at all sorts of
>>> gas stations, that the errors due to top offs, temperature changes,
>>> pump accuracy etc. should be pretty much netted out. At the end of the
>>> day, the true cost of fuel for the car is what I actually pay for it
>>> and pump into the car, and not what the meter in the car might tell
>>> me. Dividing that by the number of miles I drove as shown on the
>>> odometer will yield the true MPG.
>>>
>> Right. Your readings and calculations are valid for your car. Isn't
>> there a site where a wide range of such readings and calculations have
>> been posted? Damned analog devices. Hard to get consistency in mass
>> production.
>>
>>
> No, not an analog issue (except for the fill-ups).
> How come PriusGeek reports a 5.2% difference and I get about 3% for the
> same calculation? I have a 2005. Is the "classic Prius" different?
> Does anyone know exactly how the MPG display is calculated? Is it the
> calculation of the total fuel through the injectors divided by the
> distance covered, or some kind of a weighted average?
That's the analog part Al. Open the injector and some fuel squirts in. How
much? Well, that depends on fuel pump pressure and how long the injector is
open. Yes, you can count the times you open the injector and go digital all
the way to the display, but the part that counts (pun intended) is analog.
>>> Well, my 92K mile experience would differ. While there are
>>> variabilities in individual fillups, over the span of 3 years where I
>>> logged each of 203 fillups and the number of miles between them and
>>> found that the MPG display in the Prius was 5.21% higher than the
>>> calculated MPG. It was pretty consistent; a few times higher and a few
>>> times lower. I have to believe that over 203 tankfulls at all sorts of
>>> gas stations, that the errors due to top offs, temperature changes,
>>> pump accuracy etc. should be pretty much netted out. At the end of the
>>> day, the true cost of fuel for the car is what I actually pay for it
>>> and pump into the car, and not what the meter in the car might tell
>>> me. Dividing that by the number of miles I drove as shown on the
>>> odometer will yield the true MPG.
>>>
>> Right. Your readings and calculations are valid for your car. Isn't
>> there a site where a wide range of such readings and calculations have
>> been posted? Damned analog devices. Hard to get consistency in mass
>> production.
>>
>>
> No, not an analog issue (except for the fill-ups).
> How come PriusGeek reports a 5.2% difference and I get about 3% for the
> same calculation? I have a 2005. Is the "classic Prius" different?
> Does anyone know exactly how the MPG display is calculated? Is it the
> calculation of the total fuel through the injectors divided by the
> distance covered, or some kind of a weighted average?