Hybrid MPG Calculation?

[AirgunSavant]

Someone brought this up to me the other day.
I started thinking the basic calculations might not be the correct way to figure this out.

The car says that I got 49.7 MPG on FUEL then it said I got 3.9 EV miles too.
That was calculated against a total trip of 16.2 miles of driving.

I'd like to say for the trip I got about 50 mpg but that's not the real overall calculation.
It does not matter but I suspect calculating it all as one may not be the right way about it.
Just an interesting topic and not something that matters much.

 

[Jetronic]

No, it matters a lot...

If you don't consider the EV, you could say a simple swing is a perpetuem mobile, as me pushing it doesn't count as energy input.

It would be nice if they gave a fuel equivalent so you could see how much you saved by driving part with electric. How much kW in a gallon of fuel, and how many kW used to drive those 3.9 EV miles?

To be honest, 3.9 miles out of 16.2 doesn't sound very worthwile if your intention is to get cleaner air?

EDIT: if your car isn't a plug-in, the MPG is correct as it is.

 

[Al]

Does your car plug in?

 

[AirgunSavant]

No, its a new C-Max regular hybrid.

 

[Jetronic]

then the 49.7 mpg is as valid as for an ICE version.

 

[AZjeff]

So in reality you got 37.7 ICE MPG with the EV miles taken out? You can calculate it any way you want, the EV miles are like a 3.9 mile downhill, you traveled the miles but used no gas to do it.

 

[JHZR2]

Originally Posted By: Jetronic
To be honest, 3.9 miles out of 16.2 doesn't sound very worthwile if your intention is to get cleaner air?

EDIT: if your car isn't a plug-in, the MPG is correct as it is.


3.9 miles may not seem like a lot, but it could actually equate to hours idling at lights, stop signs, traffic, etc.

The calculation is what it is, how far you got on how much fuel. Monetizing the battery degradation is nearly irrelevant because everything degrades, including the ICE and transmission in a non-hybrid car being used in the same conditions where an EV bias helps out a lot (even if not accruing miles).

It's not like the car is buying kWh of electricity off the grid. And regarding those cars, fwiw, I recall calculating that it takes about 200Wh to drive one mile in a typical EV. So five miles is about 15c at highish US electric rates, with a far higher thermal efficiency than a car ICE, local, centralized pollution controls at a power plant, and the ability to recover lots of momentum in routine local driving. Do the math and ensure that it's truly apples to apples.

 

[AirgunSavant]

How do you come to that figure? Thanks.



Originally Posted By: AZjeff
So in reality you got 37.7 ICE MPG with the EV miles taken out? You can calculate it any way you want, the EV miles are like a 3.9 mile downhill, you traveled the miles but used no gas to do it.

 

[AZjeff]

Originally Posted By: AirgunSavant

How do you come to that figure? Thanks.



Originally Posted By: AZjeff
So in reality you got 37.7 ICE MPG with the EV miles taken out? You can calculate it any way you want, the EV miles are like a 3.9 mile downhill, you traveled the miles but used no gas to do it.





You got 49.7 mpg for 16.2 miles but 3.9 were EV miles so 12.3 were ICE miles or 75.9% of the total miles so 75.9% of 49.7 is 37.7mpg, might not be exact, who knows how the car does it.

 

[Jetronic]

Originally Posted By: JHZR2
Originally Posted By: Jetronic
To be honest, 3.9 miles out of 16.2 doesn't sound very worthwile if your intention is to get cleaner air?

EDIT: if your car isn't a plug-in, the MPG is correct as it is.



It's not like the car is buying kWh of electricity off the grid.


At the time, I didn't know if he drove a plug-in or not. If his car is a plug-in, the car would be buying kWh from the grid... that's why I immediately ammended my post, to make the distinction with plug-in versus not.