How did GM arrive at 230 mpg for the 2011 Chevrolet Volt?
Neither General Motors nor the EPA are making declarative statements about how, exactly, the 2011 Chevy Volt will achieve it's much-touted 230 mpg rating that was announced today. GM's most clear statement (available in full after the break) says that some consumers "may be able to be in pure electric mode on a daily basis without having to use any gas" and that "key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day."
Without access to the actual method that the EPA is tentatively going to apply to plug-in vehicles (we have requests for clarification out to the EPA), all that GM's Dave Darovitz would tell us is that the number is "based on city cycles and we're not really talking in detail yet." Instead, the press release says that:
Frank Weber, vehicle chief engineer for the Volt, told AutoblogGreen that the EPA's method takes into account the two extremes: People who plug in every chance they get and therefore barely ever need gasoline and people who never plug in (if you're buying a Volt and never plug it in, we'd like to offer you a bridge or two. Call us). By figuring out what the average driver will do with the Volt, the EPA has declared that 230 mpg is reasonable. Weber said, "The number is in the ballpark, it is not unrealistic. The moment you are driving shorter trips, or you go on longer trips and look at your average fuel economy, this number is achievable."Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA's methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.
Keep in mind, that 230 mpg number is only valid in city driving, though GM claims that the Volt's combined mpg rating will still be in the triple-digit range. Though the EPA has yet to finalize its methodology, we have come across a calculation that makes sense. According to a commenter on TTAC.com, the EPA would first drive a PHEV with a full charge until it reaches a charge-sustaining mode, after which it completes a normal cycle of 11 miles. The Volt, therefore, would presumably go 40 miles before activating charge-sustaining mode, and then travel another 11 miles for a total of 51 miles. Thus, GM can claim the Volt will achieve 230 mpg based on 51 miles of driving during which only .22 gallons of fuel would be used. Likewise, if we know the Volt would use .22 gallons of fuel while traveling 11 miles in charge-sustaining mode, we can calculate that it would achieve 50 mpg while traveling with the generator on.
However, as you can read in this detailed PDF from NREL, there is much more to think about in calculating the fuel economy of a PHEV than simply how far it can go on a single charge and then what its "regular" mpg rating is. We'll just have to wait until the EPA finalizes its methodology for testing these types of vehicles before we can say for certain how GM arrived at the magic number of 230 mpg.
[Source: GM, NREL]
PRESS RELEASE:
Chevrolet Volt Expects 230 mpg in City Driving
* First mass-produced vehicle to claim more than 100 mpg composite fuel economy
* Tentative EPA methodology results show 25 kilowatt hours/100 miles electrical efficiency in city cycle
* Plugging in daily is key to high-mileage performance
WARREN, Mich. - The Chevrolet Volt extended-range electric vehicle is expected to achieve city fuel economy of at least 230 miles per gallon, based on development testing using a draft EPA federal fuel economy methodology for labeling for plug-in electric vehicles.
The Volt, which is scheduled to start production in late 2010 as a 2011 model, is expected to travel up to 40 miles on electricity from a single battery charge and be able to extend its overall range to more than 300 miles with its flex fuel-powered engine-generator.
"From the data we've seen, many Chevy Volt drivers may be able to be in pure electric mode on a daily basis without having to use any gas," said GM Chief Executive Officer Fritz Henderson. "EPA labels are a yardstick for customers to compare the fuel efficiency of vehicles. So, a vehicle like the Volt that achieves a composite triple-digit fuel economy is a game-changer."
According to U.S. Department of Transportation data, nearly eight of 10 Americans commute fewer than 40 miles a day http://tinyurl.com/U-S-DOTStudy .
"The key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day," Henderson said.
Volt drivers' actual gas-free mileage will vary depending on how far they travel and other factors, such as how much cargo or how many passengers they carry and how much the air conditioner or other accessories are used. Based on the results of unofficial development testing of pre-production prototypes, the Volt has achieved 40 miles of electric-only, petroleum-free driving in both EPA city and highway test cycles.
Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA's methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.
The Chevrolet Volt uses grid electricity as its primary source of energy to propel the car. There are two modes of operation: Electric and Extended-Range. In electric mode, the Volt will not use gasoline or produce tailpipe emissions when driving. During this primary mode of operation, the Volt is powered by electrical energy stored in its 16 kWh lithium-ion battery pack.
When the battery reaches a minimum state of charge, the Volt automatically switches to Extended-Range mode. In this secondary mode of operation, an engine-generator produces electricity to power the vehicle. The energy stored in the battery supplements the engine-generator when additional power is needed during heavy accelerations or on steep inclines.
"The 230 city mpg number is a great indication of the capabilities of the Volt's electric propulsion system and its ability to displace gasoline," said Frank Weber, global vehicle line executive for the Volt. "Actual testing with production vehicles will occur next year closer to vehicle launch. However, we are very encouraged by this development, and we also think that it is important to continue to share our findings in real time, as we have with other aspects of the Volt's development."
About Chevrolet
Chevrolet is one of America 's best-known and best-selling automotive brands, and one of the fastest growing brands in the world. With fuel solutions that go from "gas-friendly to gas-free," Chevy has nine models that get 30 miles per gallon or more on the highway, and offers three hybrid models. More than 2.5 million Chevrolets that run on E85 biofuel have been sold. Chevy delivers expressive design, spirited performance and provides the best value in every segment in which it competes. More information on Chevrolet can be found at www.chevrolet.com. For more information on the Volt, visit http://media.gm.com/volt/.
General Motors Company, one of the world's largest automakers, traces its roots back to 1908. With its global headquarters in Detroit, GM employs 235,000 people in every major region of the world and does business in some 140 countries. GM and its strategic partners produce cars and trucks in 34 countries, and sell and service these vehicles through the following brands: Buick, Cadillac, Chevrolet, GMC, GM Daewoo, Holden, Opel, Vauxhall and Wuling. More information on the new General Motors Company can be found at www.gm.com.
Reader Comments (Page 1 of 6)
Vizel 12:46PM (8/11/2009)
except for the fact that you are literally just replacing ur gas bills to ur electricity bills?
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UCJR 2:19PM (8/11/2009)
Considering mass produced electricity from power plants costs pennies compared to gasoline, it's basically like getting a free 40 miles.
Think about it: it'll cost 50 cents per 40-mile charge, versus $3.00ish in gas for that same 40 miles.
mortonb11 1:33PM (8/11/2009)
or if you did your research...charging the volt would take as much energy as an air conditioner, and even that is much better than relying on oil based fuels. ...I really think your missing the point.
Kevin 12:39PM (8/11/2009)
Ugh...
If I were to buy this car, I would be plugging it in every night, and probably not drive more than 40 miles every day, and if I did, I would not complain because the car still would get fantastic numbers driving around in the city.
I could also drive the car quickly, like 0-60 in the upper 7's! Show me a Prius that can do that!
But I will wait until the second-gen comes out because the first 10,000 they are making will be very expensive...even with the tax credit.
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audi_arena 12:56PM (8/11/2009)
My daily commute is 4.5 miles a day, city driving, but because I live in the city and park on the street, I can't plug the car in...
... if there was a standardized plug that could only be used on electric cars, it would be very easy for cities to install charging stations where there are currently parking meters, and using infrastructure that is allready in place for making quick credit card transactions, this could be an excellent source of revenue.
Kevin 1:00PM (8/11/2009)
I like your thinking. Maybe you can start a business??!
For any and all information regarding the vehicle, here is a GREAT website to follow news on it:
www.gm-volt.com
Kitko 1:05PM (8/11/2009)
Kevin, there's no need to show you a Prius because Prius and Volts are very different vehicles, very different concepts.
BTW, I wonder how will the batteries perform in sub-zero temperatures....
Kevin 1:12PM (8/11/2009)
I do understand, Kitko. But the basic premises are the same: to use the least amount of fuel as possible.
The volt's battery will not be able to perform well in extreme temperatures, as these batteries' ideal temperature is around 75* F. When the car is plugged in, it will use grid power to keep the battery at optimal temperature, and if it not plugged in, the ICE will help return the battery to a normal temperature quickly. If it's cold, the ICE will start when the car is started, and heat up the battery, and turn off once that is done. I'm assuming if it's hot, the battery will be able to draw energy from it self in order to power A/C and cool itself off.
A lot of that information is on the website I posted earlier. :)
amnigo 1:13PM (8/11/2009)
Already patents out for this kind of stuff. Has been talked about and I think a number of cities are using stimulus money to begin implementation of the parking meter infrastructure.
Danimal 1:14PM (8/11/2009)
audi_arena: I agree. The fuel economy whatever it is will be impressive. The price is a lot but there are people that pay to have the latest and greatest (HD tvs, iPhones, PS3's, etc)
The only real problem I see is attracting city dwellers who live in apartments or condos with only street parking.
zamafir 1:19PM (8/11/2009)
"if there was a standardized plug that could only be used on electric cars, it would be very easy for cities to install charging stations where there are currently parking meters, and using infrastructure that is already in place for making quick credit card transactions, this could be an excellent source of revenue."
That's what I don't get. When i go downtown i see one sort of plug, when i return to the apartment we've got another. I know a standard is being worked on... like you I'd love to see this near parking meters, or run like most urban centers, just pay at a central station and start charging… though how would you prevent people from tampering with your car?
Kitko 1:20PM (8/11/2009)
Kevin, I understand that you play for GM and I know well that batteries in low temps suck power. The point is that you do so much to compensate for the defficiencies of the Volt's systems that in the real life it will probably offer only marginally better economy than, say, prius.
Kevin 1:29PM (8/11/2009)
Play for GM? hmm...
Can you plug a Prius in and drive for 40 miles without using gasoline?
That fact will over come it's other "deficiencies" when the ICE is needed.
TigerMil 2:05PM (8/11/2009)
EPA/GM must be an acronym for eff the public. $2.75 worth of electricity to go 100miles with gas at 2.75/gallon means about 100mpg equivalent. A long effing way from 230mpg. Someone is lying and their initials are GM and
EPA.
John 12:40PM (8/11/2009)
Oh boy. I hope for their sake that when these are in the hands of consumers, the actual mileage comes close to this. Otherwise - big time egg on the face. While it is a great PR move to shout this number, if there is a lot of debate about the methodology, it may blow up later. Hopefully they are erring on the conservative side with the estimate.
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Jake 12:42PM (8/11/2009)
Direct Rectal Pull???
Well, when the EPA and GM are run by the same scam artists, I guess the numbers can say whatever they need to say.
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Kevin 12:45PM (8/11/2009)
*facepalm*
Not even worth arguing with you...
Jake 12:51PM (8/11/2009)
But, I am clearly worth responding too. So, thanks. Have a nice day.
(rolls the dice with comment reply system)
AngeloD 12:45PM (8/11/2009)
The sign behind the podium looks like it says 23 mpg, not 230.
GM can't seem to get even the most trivial things right.
Next thing they'll probably do is shoot a gay dance video for the launch of the Volt like they dd for the Camaro.
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Ted 1:07PM (8/11/2009)
My sentiment exactly on the sign. Pathetic that nobody in the organization noticed that, especially on such a much-hyped product.