[Tgun]

Good day all;

I conducted some rather detailed analysis and came to the realization that PHEVs like the Chevy Volt DO NOT take into account the electricity consumption (used when plugged-in recharging is being utilized) when calculating Miles Per Gallon.

Ok- here's the deal, you can combine the Electricity and Gasoline (or other alternative fuel) to determine what I termed True Fuel Economy. This is a much more realistic and accurate method for comparing PHEVs to other vehicles.

I have copyrighted my white paper on TFE and the formula/methodology and have submitted it to the EPA recommending it be used for ALL PHEV vehicles MPG testing.

For example, Affinity claims their PHEV obtains over 150MPG. Well, once I ran the calculations, the actual True Fuel Economy (including electricity consumption) was only 50MPG. Quite a difference!

Not much better than my little Honda Fit which averages 38MPG and in which I have regularly achieved 45MPG in pure highway driving at 70 MPH.

I am contacting General Motors and pitching my TFE white paper and formula, for a fee of course. Maybe I can negotiate a royalty, you know maybe a few $ per PHEV sold.

Would be a nice revenue stream!

 

[cburk]

I don't see the point of your calculations. When people think MPG they are thinking how far can I go on one gallon of gas that I buy at the gas station. If an electric range extender allows them to go 150 miles on burning one gallon of fossil fuel that is all they are going to care about. The reason for this, is because the amount of money it costs to recharge your Volt isn't going to amount to squat. Add in homebrew solar, plugging in at work, running an extension cord to your neighbors outdoor outlet, LOL, etc and your recharge costs come down to zero. You could spend your lunch hour metal detecting and find enough change to pay for your daily battery recharge.

So maybe your calcs are correct but there is no way in heck that GM or any other electric car maker is going to market their car based on your calculations. If they did the Volt would look worse on paper than a civic hybrid.

 

[MetrologyFirst]

cburk is right. These calculations don't matter. Well, it does if you wish to support a brand that has decided not to produce plug in cars, like Honda.

Oh, and I seriously doubt that a 100hp 1.7l Honda Fit, rated at 27mpg city, 34 mpg highway, is "regularly" acheiving 45 mpg at a constant 70 mph.

Maybe down a hill.....

 

[BigRedFed]

I personally think that it matters for EREV's to make a distinction between the miles achieved in electric mode versus the miles achieved while running on gasoline. I believe that it could seem to amount to fraud and lead to false advertising claims. That is why I believe GM has been careful in not making the same mistake as people on this forum. As far as I can remember, I have not seen a quote from GM stating that the Volt will get anything over 50-60 mpg running in full ICE mode. Someone correct me if I am wrong.

 

[Tom]

Modified SAE Procedure J1711

A paper was written last year "Measuring and Reporting Fuel Economy of Plug-In Hybrid Electric Vehicles" by Jeffrey Gonder and Andrew Simpson to modilfy SAE procedures. They recommedend using Mpg = Distance/(Gallons of fuel +(Energy Electric/Energy Gasoline)).

 

[gripperdon]

Tgun Dumb

I don't equate my nuclear power sourced electricity to gasoline. Sound like a spoiler looking to spoil. and a royalty ! Why ?

 

[JoeReal]

Oh, and I seriously doubt that a 100hp 1.7l Honda Fit, rated at 27mpg city, 34 mpg highway, is "regularly" acheiving 45 mpg at a constant 70 mph.

Maybe down a hill.....

or behind a speeding big rig or being towed...

Mythbusters have shown you can achieve about 35% (must not remember the exact value right) improvement in mpg if you follow behind big rig at certain distance. And so it comes out close to 45.9 mpg for a 34 mpg car.

 

[Koz]

or behind a speeding big rig or being towed...

Mythbusters have shown you can achieve about 35% (must not remember the exact value right) improvement in mpg if you follow behind big rig at certain distance. And so it comes out close to 45.9 mpg for a 34 mpg car.

And a plug-in like the Volt will get about 65 miles AER. One the exaggerated impact of drag on EV's cuts both ways. Because of their steady, high efficiency they get exaggerated benefits from drafting. This is why the real world performance will be better than simulated for most people for their rush hour commutes.

 

[Greenman]

Royalty?

I don't equate my nuclear power sourced electricity to gasoline. Sound like a spoiler looking to spoil. and a royalty ! Why ?

I do think that having a standard to compare energy use per mile would be a good thing. I'm not sure how you would value all the costs of War, Greenhouse Gases, auto maintenance, energy economy, purchase price, and resale value into a number that people would understand, much less worship.

Personaly, I'm turned off by the idea of royalties for anyone that doesn't deserve them. We pay royalties every time we purchase a car, a gallon of gas, a carbon credit.

What's wrong with telling businesses that they should reduce carbon emissions or else. The penalties can be fines, prison or both.

 

[hermant]

I'd agree that it would amount to fraud not to take into account the amount of electricity used in comparing the efficiency of various types of PHEVs. I don't exactly know how to do it in a universally standardized manner but it is absolutely necessary. You'd have to come up with some unit of energy that can be easily and precisely converted between gallons of liquid petro-fuel (gasoline and diesel), pounds of volatile gas (hydrogen and natural gas), and kWH of charge (electricity). Then you could back-calculate to a comparable MPG value (such as when measuring against required CAFE standards). Without this standard approach, you'll never be able to do a meaningful, apples-to-apples comparison between different forms of PHEVs.

 

[Texas]

I'd agree that it would amount to fraud not to take into account the amount of electricity used in comparing the efficiency of various types of PHEVs. I don't exactly know how to do it in a universally standardized manner but it is absolutely necessary. You'd have to come up with some unit of energy that can be easily and precisely converted between gallons of liquid petro-fuel (gasoline and diesel), pounds of volatile gas (hydrogen and natural gas), and kWH of charge (electricity). Then you could back-calculate to a comparable MPG value (such as when measuring against required CAFE standards). Without this standard approach, you'll never be able to do a meaningful, apples-to-apples comparison between different forms of PHEVs.

Actually this is much harder than you may think. There are several factors like the cost of the grid electricity for the consumer, how many miles they drive, what kind of driving they do, etc. I'm sure they will come up with some standard of comparison. Today's EPA standards are also subject to debate and that is relatively easy when compared to vehicles that use duel sources of energy at varying percentages. Don't get your panties in a twist. Auto manufacturers will be bashing every other manufacturer and there will be lot's of consumer reports and comparisons. Things will be fine. Please sleep well.

 

[MrParrot]

Hi. New guy here. I tend to think a little outside the box. I once threatend one of my kids with "If you don't quit watching so much TV, I'm going to connect a generator to the exercise bike and plug the TV into the generator.". Why not design a system that would allow the exercise fanatics to be able to pedal their way to a full charge every night...?

 

[omegaman66]

Let see I don't use any gas if I drove a volt. Looks like infinity miles per gallon of gasoline and less than a dollars worth of electricity per day. You figure out the mpg... I know enough to know that my cost is a fraction of what it is now.

 

[Tom]

Volt's AER Energy MPG Spec: 167.2 miles per gallon

The Volt's All Electric Range, AER, or miles per energy rating is 40 miles for 8 kWHr. Energy per gallon of gas is 33.44 kWHr/gal. Thus the Volt's AER mpg spec equals 167.2 miles per gallon.

On the basis of cost, with a gal of gas @$4.00 and power @$0.10 per kWHr. The Volt's AER cost mpg spec is 200 mpg.

The the AER conditions have been reported to be the EPA City Cycle. For the more aggressive US06 cycle I estimate AER to be 27.5 miles and for the EPA 2008 5 cycle profile 29.6m miles.