MPGe Readout

if that is combined gas and battery, then yes. there is no hv only unless you drive hv only.

 

you wanna point out where the MPGe readout is?

 

you do know what MPGe is? right?

Fuel​

Unit​

Btu/Unit​

KWH/Unit​

gasoline gallon 116,090 34.02

 

Fuel​

Unit​

Btu/Unit​

KWH/Unit​

 

There isn't one to my knowledge. The EV Driving Ratio screen has all the information to calculate MPGe (with charging loss assumption).

 

i guess not. is it important?

 

bisco,

Its calculated for you on our PiP spreadsheet, far right side

 

thanks track! now what do i do with it?

 

so if i'm getting better than 50mpg, but less than 99mpge (pip epa rating?) does that mean i'm not going as far as i should on kwh?

 

MPGe is just a way to calculate "miles-per-unit-of-energy", factoring in electricity and gasoline (sorry if thats technically incorrect, I'm no engineer and I do not read SAE papers for fun).

Because the PiP can plug-in, MPG (miles-per-gallon of gas) is a bit of a meaningless metric, since you could get infinite MPG if you never used any gas. So MPGe is just a way to factor in the consumption of electricity too.

Personally, I dont think MPGe means much other than to be able to compare it to other cars to see which car is more efficient in its consumption of energy (gasoline + electricity or just electricity alone). It seems when it comes to regular MPG, its YMMV.. but with MPGe, its YMMVG (your mileage may vary greatly).

Looking at our spreadsheet, I dont see many folks getting into the 90s or more, even though the PiP is rated at 94 MPGe. However, if you look at our "group" average (at the top of the column), its 72.34 MPGe. If you go to Voltstats and look at the MPGe for the Volt owners, its somewhere around 60 MPGe.

Lets just put it this way.. no one that has ever asked me about my car has ever asked me what MPGe I get. And even if they did, I wouldn't know unless I opened up the spreadsheet and looked at my own numbers.

 

MPGe actually stands for "Miles Per Gallon equivalent". I don't read SAE papers for fun either, but Wikipedia has a good explanation for MPGe.

 

so what would be the point of having a gauge in the car?

 

just like prius drivers that optimize their driving styles to achieve higher MPG numbers, they could learn and apply the optimum driving styles to maximize their MPGe.

this might mean switching between EV/HV for segments of their commute, limiting their speed while in EV, changing strategy or drive route depending on temperature, etc...

 

The PC spreadhseet is a reasonable estimate for listed Pips as its based on both CS and CD measured usage.
But note the 94 MPGe is for the Prius in EV mode, its 50MPGe in gas mode, and so the mix (using a harmonic mean) will generally be a mix. But just a some people beat the EPA on MPG, many can beat it on MPGe in EV mode.

The voltstats data is not a reasonable MPGe estimate, its really just based on the EPA estimate for EV (95MPGe and the EV ration combined with the actual MPG combined using the EV ratio. My personal MPGe (which I track by hand using both gas and EV usage) is over 101MPGe, which is above what EPA lists as the EV MPGe. I'm way more efficient on EV than the EPA estimate (My EV only MPGe is about 125MPGe)


MPGe or any other direct feedback on efficiency could help drivers figure how to be more efficient.
The "slick graphics" that they seem to think some people want may be good for some. Others, like me, want quantitative data.

 

voltstats has a rather simplistic method of reporting MPGe. It should not be used for comparison purposes, or anything really.

my last 30 days ...

1269 EV miles, 406kWh at the plug, 345kWh in the battery, 10.2 gallons equivalent. 124MPGe

I have a regular morning drive of 21 miles that consumes 3.3kWh. I think that works out to 214MPGe

 

214 is fantastic.. are you including losses from charging?

 

No. My understanding is that MPGe should be tank to wheel rather than well to wheel. Should I ?

 

EPA measurements use wall to wheel, so I do. Think of the wall as the pump.. and its Pump to wheel, not well. (We are not looking at efficency of power generation, just delivery from the wall-- what you have to pay for).