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It appears unlikely that the government test loop could be used to accurately measure Volt emissions and fuel economy. (http://www.autoweek.com/apps/pbcs.dll/article?AID=/20080926/FREE/809269985/1023/CARNEWS)

http://www.cleanmpg.com/photos/data/501/2011_Chevrolet_Volt_Drivers_Side_Rear1.jpgHarry Stoffer and Richard Truett – Automotive News – Sept. 26, 2008

2011 Chevrolet Volt – EPA rated at 100 mpg + on the 08 EPA?

It is not electric given the second gasoline ICE power source but it is easily worth 100mpg for most over the life of the vehicle which is exactly as it should :) -- Ed.

The Chevrolet Volt could be on its way to being the first mass-produced vehicle rated at 100 mpg or more.

To ensure that happens, General Motors is asking the EPA to declare the Volt an electric vehicle for regulatory purposes. GM spokesman Rob Peterson said the California Air Resources Board has given the Volt preliminary certification as an electric.

A government rating of more than 100 mpg would give GM invaluable marketing ammunition and would be a boost for company compliance with fuel economy standards. Peterson confirmed the request today.

Loops vs. formulas

Normally, a vehicle is run on an EPA test loop, consisting of both city and highway driving, to measure tailpipe pollutants and provide data for calculating fuel economy. But for electrics, which have no emissions, the government uses a Department of Energy mathematical formula to translate energy use into some equivalent of miles per gallon of gasoline.

Using that formula, the limited-production all-electric Tesla Roadster, for example, gets rated at 244 mpg for the government's corporate average fuel economy program. Tesla officials say they look forward to being able to sell the fuel economy credits they will accumulate, even with limited sales.

The Volt is a plug-in electric hybrid, which GM calls a "range-extended" electric. Due on the market in late 2010, the Volt will be designed to go 40 miles on all-electric power. Then a small internal combustion engine would kick in to extend the range… http://www.autoweek.com/apps/pbcs.dll/article?AID=/20080926/FREE/809269985/1023/CARNEWS

Failing to take the kilowatt-hour input into account is going
to be one of the biggest public-facing screwups they can possibly
pull with any of these vehicles. We already have too many
instances where a claimed "100 MPG!" is a flat-out lie just for
PR purposes. It *is* going to bite them all in the ass someday --
just because something plug-charges all or part of its onboard
energy, doesn't mean it's free, and the hue and cry when the
public finally looks at its nearly-doubled electric bill and
realizes this the hard way is going to be hilarious.
.
You heard it here first.
.
_H*

Failing to take the kilowatt-hour input into account is going
to be one of the biggest public-facing screwups they can possibly
pull with any of these vehicles. We already have too many
instances where a claimed "100 MPG!" is a flat-out lie just for
PR purposes. It *is* going to bite them all in the ass someday --
just because something plug-charges all or part of its onboard
energy, doesn't mean it's free, and the hue and cry when the
public finally looks at its nearly-doubled electric bill and
realizes this the hard way is going to be hilarious.
.
You heard it here first.
.
_H*

Agree 100%. "MPG" is no longer meaningful when the vehicle has power sources other than gasoline. We're going to need some more complete measurement that's easily digestible by the public, and soon, with the Volt and the factory-PHEV Prius III both supposedly coming out within a few years. What units would make the most sense? Cost per 100 miles? Miles per 100 kWh (1 gallon of gasoline ~ 37kWh)? Miles per 100 MJ (megajoules)? Furlongs per 1.21 gigawatts? :D

Agree 100%. "MPG" is no longer meaningful when the vehicle has power sources other than gasoline. We're going to need some more complete measurement that's easily digestible by the public, and soon, with the Volt and the factory-PHEV Prius III both supposedly coming out within a few years. What units would make the most sense? Cost per 100 miles? Miles per 100 kWh (1 gallon of gasoline ~ 37kWh)? Miles per 100 MJ (megajoules)? Furlongs per 1.21 gigawatts? :D
Wouldn't that be 1.21 Jigawatts?;):p

Hi Al:

___ARB includes an mpg per gallon equivalent in their calc's but where a PHEV sits will be a question for interpretation. You and I know that a CleanMPG'er gets a hold of one and it will use maybe 150 gallons or less of fuel over 100,000 miles. At that point, it will be well beyond 100 mpg per gallon equivalent including the electricity to charge the pack back up just as the Tesla is rated at 244 mpg per gallon equivalent. What will happen with the average Joe however that forgets to plug it in and burns a few thousand gallons over its lifetime is just like those that pull low 30’s from a Prius with 2 mile Power down jaunts again and again.

___I believe Google’s Recharge program will be a close to final solution in this debate and even than, the Volt should easily exceed 100 mpg per gallon equivalent which includes the electricity to charge. 40 miles is a long distance not burning any oil and that is going to be its claim to fame.

___Good Luck

___Wayne

To me it seems like it should be rated on it's equivalent use. GM claims that 80% (IIRC) of people travel 40 miles or less a day, so weigh the score 80% of it's equivalent electric mpg, and the weigh the other 20% what it gets using gas. So for example say it gets 200mpg equivalent on electric power and 40mpg on gas. It's mpg would be for example 1/(.8*(1/200) + .2*1/(40)) = 111.11mpg.. This is my idea for rating, and I think it's more or less what the epa is going to use.

Sure, accuracy is important.....and I hope for something clear like cost/mile or MPGG or whatever.

But if there is an insistence on MPG for some dumb reason, then let's see 100mpg. Of all the mpg figures, it's the closest. 90% of the public drives under 40 miles a day. Those 90%, assuming they plug-in, will get a cost/mile somewhere in the ballpark of 100mpg equivalent.

This car needs to sell, and sell a lot. I don't want to see anything close to my Prius. That's just wrong.

The sticker in the window should tell electrical energy use per mile, city and highway cycles. Also mpg on those cycles in charge sustaining mode (the FE it would get without plugging in, not the combined result). And finally, miles on the city and highway cycles from full charge until the engine comes on.

For CAFE requirements? 100 is fine with me.

MPG would a useful guesstimate to approximate fuel consumption against a '56 Studebaker.

Bad numbers are bad numbers. Develop a true metric, or we'll be comparing consumption in the equivalent of gills per league.

Hi All:

___If there is one fly in the ointment wrt the Volt, it that 35 mpg nonsense when in the Charge Sustaining mode. I am just considering GM’s latest range figures vs. the speculated on extremely small capacity fuel tank. If a pure serial hybrids FE is really that bad, Toyota’s HSD-III variants are going to eat the Volt alive.

___Good Luck

___Wayne

I'm not sure where this info is coming from. They cut the tank size in half from the original 12g to 6g. Stated total range is supposed to be 350-400mi. Take the low end of 350mi, remove the 40mi AER, and you get 310mi/6g = 51.7mpg... hence the source of "about 50mpg after depletion" comment we've seen in various articles.

Seems like to me there should be 2 or 3 ratings for efficiency.

You gotta say how far the car goes per unit of electricity, and how far per unit of gas.

But it seems like with this new plugin stuff you should also be stating how far it goes per full charge, though that is kind of backwards cause we don't say how far cars can go today per tank of fuel.

Hi Sean:

___I have not read 6 but have read 7 to possibly 8. We have to believe a Serial hybrid in CS mode will pull 50 as it has all he tools of a Prius but it should be interesting when it arrives if it does not.

___Good Luck

___Wayne

Seems like to me there should be 2 or 3 ratings for efficiency.

You gotta say how far the car goes per unit of electricity, and how far per unit of gas.

But it seems like with this new plugin stuff you should also be stating how far it goes per full charge, though that is kind of backwards cause we don't say how far cars can go today per tank of fuel.

Multiple ratings would give the most accurate picture, but wouldn't provide that nice overall estimate that's staring you in the face today (after all, it is only an estimate). I still think you need that one overall estimate, and probably the other ratings as subheadings under it for those who care. The question remains, how do we compare different types of fuel?

Cost-based comparisons ($/mile or MPG based on fuel cost rates) are useful for a single point in time, and probably would resonate very effectively with consumers. The problem is that they are useless over time. You couldn't compare between model years because fuel costs are so fluid (for that matter the comparisons may be useless next week).

Ultimately, though, that overall estimate will be tricky to get right. The US has effectively standardized their FE ratings based on MPG, and even then lots of fuels vary on how much energy there is per gallon (and not even going into what a "gallon" of electricity would be). It'd be nice to have a uniform standard.

I'd just issue 2 ratings. The first is simple. Drain the battery & then let it run it as a standard hybrid with no plug in. That gets one important number.

A second calculation would need to be done (but not necessarily shown) where the run in run on electric only & an average range calculated. Based on this and the first number, present a graph showing average electricity & gas used daily based on miles driven daily (assuming plug in only occurs once a day). The graph should show from 0 to 250 miles. The power usage should include costs of having the car plugged in for a full 8 hours a day even if it didn't need to be (like a cell phone charger that may waste power when it isn't really needed).

Finally, using a national $ average for gas/electricity (same for all cars testing in a given year), a 2nd graph show "fuel" cost to operate based on the same 0 to 250 miles per day.

And if you want to add one more thing, generate a average single fuel cost for the vehicle and the average of similar vehicles (can you say EPA Energy Guide label".

That should all be able to fit on standard 8.5x11 sticker.

I think the series hybrid PHEVs are a lot easier to qualify and the AVTA test results for the Renault Kangoo serial hybrid probably show how they will do the Volt.

PDF link to Kangoo AVTA test results

http://avt.inl.gov/pdf/phev/KangooFact.pdf

I would like to see:
1. AER range for urban/highway cycles with AC-Wh/mile (could mention MPGe for combined but not really needed.) from fully charged battery or/at 8 hours charge.
2. MPG for urban/highway cycles in CS only mode

Anything in between AE and CS is just too dependent on driving pattern but picking the US average pattern and giving annual AC-kWh, gallons, CO2 and estimated cost would be informative.

Good Luck
Andrew