The New York Times has now taken a stab at the Volt fuel efficiency rating debate. As we know, the car will drive for 40 miles on battery without gas (charge depleting mode), and then 50 mpg thereafter should it need to, up until the point it is recharged (charge sustaining mode).
The article states confidently that the Volt will be given at least a 100 mpg sticker, more than double the current Prius, and be the first car to break the 100 mpg barrier. It is noted that mpg rating is the “EPA’s reasons for being” and that determining the Volt’s mpg is necessary because it carries gas and consumers have to be capable of comparing it to other vehicles.
An EPA cycle is a prescribed 11 mile driving course (city or highway). There have also been new cycles created for electric cars that consider HVAC use.
The Tesla it turns out, since it doesn’t use gas, is rated purely in kwh per 100 miles, 33|33 to be exact. This can be converted into gas equivalents, but the result is either 105 mpg or 256 mpg city, depending on how one does the calculation.
Mike Duoba from Argonne national Lab explains the likely method with which the E-REV Volt will be tested.
First, it will be driven repeatedly over each EPA cycle until the battery is depleted. Then the amount of electricity consumer per miles driven is determined.
Next the car will be driven repeatedly at the charge sustaining mode using the gas generator. Miles per gallon are then calculated.
Finally the two values are combined, taking into account the utility factor. This value represents the percent of times all driver are expected to be in each of the modes. Based on previous data, this would mean 78% of driving would be expected occur in charge depleting mode.
In the end Duoba predicts the Volt will beat the 100 mpg
Source (New York Times)
This entry was posted on Sunday, November 16th, 2008 at 7:40 am and is filed under E-REV, Efficiency. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.
Nov 16th, 2008 (7:59 am)“..and then 50 mpg thereafter should it need to, up until the point it is recharged (charge sustaining mode). ”
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I am still highly skeptical on this 50 mpg rating. dragging around the extra weight of the battery/generator seems to make this goal difficult, at best.
Its time to take a “wait and see” attitude.
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I would prefer to see a miles/KW-hr rating, along with the size of the battery (ie: KW-hr storage capacity, and its expected range). Then, a separate mpg rating when running in gas mode. This makes it clearer to the average Joe, and allows them to better understand how this would affect his driving requirements.
Nov 16th, 2008 (8:07 am)I noticed the $.20/kwh on the label. National averages this July (peak cooling season) were around $.12/kwh. No place outside Hawaii/Alaska paid more than $.20/kwh. New England/Mid-Atlantic were close to .$20/kwh. So the $.20 will sound high to most of us, but about right for those in NY and CT.
http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html
+1
Nov 16th, 2008 (8:53 am)Nutshell:
All assumptions are invalid until the Volt is recognized as getting 40 miles on at peak speed on the highway, which is 75 mph for many places (80 in West Texas). Still waiting on a GM comment on how the 40 miles breaks down.
All assumptions are invalid until the Volt is recognized as getting 50 MPG when the battery is depleted, a case could have been made previously when it was expected the Volt would/could dip into its battery reserves after the electric portion was used up (especially under driving conditions that required harder acceleration). Now we have GM on record as basically saying, you are getting 40 miles and that is it, there is no advantage to the battery after that…it is just 400 pounds of dead weight (ie- no battery regen, no overuse..all but a trickle charge goes direct to motor from the ICE), the math/physics of 50 MPG is now impossible in my opinion.
I’ll just wait myself until there is a production-alike Volt prototype out there, driven and tested by someone that isn’t on the payroll to belive the claims.
I still find the whole blended MPG thing disengenuious and not a good measurement for the consumer as real world results will generally be much higher or much lower for the average user.
I still don’t understand how you can peg this number at all, with gas prices fluctuating even this year from the low at $1.80 in some places to almost $5.00 at the high in other places. What about regional electric prices and price changes there? Will these stickers be reprinted and pasted to cars every week? Will the EPA reset the number on a daily basis online at http://www.fueleconomy.gov/ ? Seems to be the data set will only be right on the day it is printed.
I will go out on a limb and say the day the EPA releases this number and their range calculations that the resulting commentary is more likely to be how the Volt does NOT get 50MPG and possibly how it does not get 40 miles electric on the highway under ‘normal’ use…and not the blended MPG number at all.
Much like the quarterly results cuts through GM’s financial BS, this report will be the measure of GM’s honesty on the Volt program.
Nov 16th, 2008 (9:03 am)Here are two interesting MPG articles. I still like the EREV Volt.
STUCK IN LOS ANGELES TRAFFIC OR ROLLING along a Southern California freeway, the Honda FCX Clarity looks like any other small four-door sedan. But the Clarity — 200 are now on the road, all leased to drivers living near Santa Monica — is powered by a hydrogen fuel cell. It gets the equivalent of 74 miles a gallon (or, more accurately, 72 miles per kilogram of hydrogen), can travel nearly 300 miles between refueling and sends water vapor, not pollutants, through its exhaust pipe.
___________________________________
With its quirky vintage cars and grease-stained floor, Pat’s Garage looks like a typically hip San Francisco auto repair shop. Until you notice that the street outside is over weighted in Toyota Priuses and inside, against the wall, stands a stack of $10,000 batteries made by A123 Systems. Drop one of these 185-pounders into the spare tire well of the Prius, get garage owner Patrick Cadam and partner Nicholas Rothman to tinker with it overnight, and you’ve got a hybrid that can be plugged into any outlet for maxing your gas mileage. Rothman, fluent in Japanese and a certified Prius technician, says he’s performed more than 100 upgrades and is “addicted” to keeping the car’s fuel economy at 99.9mpg, which is as high as its display goes.
=D~
Nov 16th, 2008 (9:31 am)it’s 0 mph for the Volt unless GM survives !
+1
Nov 16th, 2008 (9:34 am)I think for this vehicle, there should be a test that includes toping the car off in terms of electricity and gasoline, and then drive it until both sources of energy are depleted. At this point the vehicle range can be calculated. For example, one test can be done in the city, another in the highway. Also one test can be done in flat terrain and one on rugged hilly roads. Then the average range could be calculated. I must admit that this is not the most scientific procedure, but it would yield a much more realistic range for this type of vehicle
Nov 16th, 2008 (9:57 am)Finally, a post about the vehicle.
Nov 16th, 2008 (10:20 am)I would like to know: City/highway all electric, city/highway all gasoline, and Kwh to fully charge the battery from customer depletion.
Any combination of the electric and gasoline data is a made up number. It will be different for everyone. If I drive 140 miles between charging it could be 70 mpg. If I drive 90 miles it could be 90 mpg. If I drive 65 miles it could be 130 mpg. To say it gets any one of those numbers is misleading.
I my daily commute is typically 8 miles but could be up to 30-40 miles mixed driving and would go beyond the AER only on weekends. So less then 30% of my driving would be gasoline powered. Consumers need to know their driving habits to be able to make an informed decision about this car. Saying it gets 100 mpg without additional information would be for an ignorant consumer that doesn’t want to think who would then complain when the car doesn’t get the range they thought it would get.
Nov 16th, 2008 (10:49 am)With only 50,000 units be promised in the first couple of years, the average Joe will not be buying this car for some time. Hopefully by the time Joe the plumber wants to buy a e-rev, the battery will be improved to the point where these vehicles get rated like the Tesla which is no gallons to the mile because it is all electricity.
Nov 16th, 2008 (10:56 am)#1 JEC & #3 Statik
A few points:
The 40 mile range is for combined city and highway. The Volt will not have a 40 mile range at highway speeds. It’s been estimated to be more like a 28-30 mile range at highway speeds. Someone — I should remember who but forgive me — has done a fabulous job of estimating the ranges for the various tests. You can find them in the engineering section of the forum. They are really very well done.
The 50 mpg is not going to factor into the equation very much. Think about it. If 80% of the distance is driven using no gas at all, then even 20 mpg for 20% of the distance gets you to a 100 mpg number. This is why you can be confident that the Volt will get a 100 mpg rating.
There is nothing wrong with the tests and the way they’re combined. This is one time and in one area where the EPA has gotten it right. Additionally, blending the numbers is not some ruse but a very defensible and scientific way of coming up with a real viable number. The level of integrity and sophistication is high and is based on real world usage of not only how many miles drivers go per day but how aggressive they are in getting there. It’s all very good stuff.
Yes it’s true that these numbers will not fit every driver. But the existing number doesn’t fit every driver either. If you drive 90 mph on the highway or go up the Grapevine every day you won’t come anywhere close to the number on the sticker. Drive 55 on flat roads and you’ll easily beat it. Any number will always be dependent on your driving habits.
Because of the driver variations and the pluses and minuses of the Volt technology, in some extreme cases the Volt may not get better mileage than some other alternatives. However, overall, it will use 80% less gas than a car like the Prius. That’s significant and a fact which you can’t lose sight of.
Finally I doubt the 40 mile range will be there for long. Just using A123 batteries should increase the range to 60 or 70 miles because the Depth of Discharge can be greater. Using A123 batteries and doubling the capacity to 32 kWh should just about quadruple the range to 150 miles.. And the great thing is that this type of upgrade is easily done and quite likely as we move up the learning curve and the price of the batteries drop. That is ultimately the beauty of the E-flex solution — it can seamlessly accommodate the expected advances in battery technology.
Nov 16th, 2008 (10:57 am)100 miles per gallon is completely valid! But we NEED to stop using miles per gallon and start using miles per MJ. Increasingly, we don’t burn gasoline to go places – even if we use other liquid fuels, the numbers won’t make sense because other fuels have different energy densities.
See http://www.americanenergysolver.com/wordpress/?p=44 for a more complete analysis of the Volt.
Nov 16th, 2008 (11:12 am)For anyone who is interested here’s one of the threads started by Tom in the Engineering Forum I was referencing:
http://gm-volt.com/forum/showthread.php?t=581
Note that the first of the three driving profiles seems to be the 11 mile combined city/highway driving simulation which Lyle was referring to.
Nov 16th, 2008 (11:22 am)The EPA needs to have seperate labels based on their energy source: fossil fuel (gasoline, diesel, etc.), electric grid, hydrogen, etc…and it appears to be the policy. However, the Volt will have fossil fuel and electric grid as energy sources; so it should have a “hybrid label” (pun intended) explaining the energy usage. If a company produces a fuel cell (hydrogen) plug in (electric grid) vehicle, it would get a “hybrid label” also.
It is time to face the facts…calculating energy usage is at least twice the work for a vehicle like the Volt. It is more confusing to use a rating system that is designed for one energy source…with significantly more experience with a fossil fuel energy source.
40 AER 50/50 city/highway
The real numbers can be calculated with the production Volt. Hopefully, the numbers will be higher.
Nov 16th, 2008 (11:44 am)I’m very fortunate. My work route is 38 miles each way. The office and Colorado are promoting several initiatives to help meet federal and State goals to mimize gas, pollution, and time on State Highways – telecommuting, which I now do twice a week; and the second is allow car pooling credits. Plug in is welcome by the office building.
Let’s go Volt.
From the heat generating by a minority of posts, there well may be a need to start imaging our nation without any significant mainstream automotive industry. If they get their way, and “let em all die” becomes the calling card this year, there would be no GM, Ford, or Chrysler, only Toyota, Honda, Subaru, Kia, and soon a slew of Chinese communist manufacturers. Since there well may be enough Americans who agree with this “let them die” attitude, I’ve also begun looking at Venture Vehicles and Volta. Hardly comparable to the Volt, but this may be the only other way I get my family off Middle-East turmoil Oil shipped over by the robber Barons.
So, recognizing the topic of this article, my MPG would be Zero. I always rent a car when going more than 300 miles and even if I’m fortunate enough to someday own the Volt, I’d still rent a car for long distance. Economically the better choice.
Nov 16th, 2008 (11:51 am)Buy American this Christmas. Buy coupons for services (restaurants, movies, beauty salons, theaters, ice cream ColdStone), etc.,
So far, $3,000 all to American-made items (Stearns and Foster mattress for my daughter heading off to college was expensive, but very nice and made right here)
Give an American a job.
The greatest gift of all would be Americans with so many EREV cars that Middle-East robber barons have oil no one wants to buy. America no longer exporting $700 billion a year over there. I’m dreaming of an American Christmas.
Nov 16th, 2008 (12:12 pm)Lyle’s post says
“…and then 50 mpg thereafter should it need to, up until the point it is recharged (charge sustaining mode).”
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Where did this number 50 come from? (reference needed)
For 60mph? 45mph? 15mph? Never starts or stops?
Somebody’s guess? hope? wish?
I don’t believe it is true under any realistic conditions.
Nov 16th, 2008 (12:19 pm)Statik, the reason you think 50mpg is not feasible is that you’re thinking about a gas engine driving the wheels through a transmission, a-la a traditional car. In that arrangement, it IS hard to get 50mpg.
An engine driving a generator, which in turn drives an electric motor can be MUCH more efficient than the above arrangement. If it were not, then trains would not use this arrangement.
Consider also, that the generator does not bear peak load – some energy is pulled from the battery under peak load, and gets replaced through a trickle charge, or regenerative braking. Thus the engine/generator is not doing all the work a traditional ICE powered vehicle’s engine does.
50mpg is very feasible. You just have to think about the engine in the correct context.
Nov 16th, 2008 (12:20 pm)RB, the number is an estimate, and HAS to come from the EPA test cycle. Look it up, I do not know what exactly it prescribes, but it is not just going around a track at one speed. There are of course different cycles for ‘city’ and ‘highway’ driving.
Nov 16th, 2008 (12:22 pm)The WSJ for this weekend includes a long article arguing in detail against any more auto bailouts, pointing out the decades long history of big investments with little to show for them.
Nov 16th, 2008 (12:25 pm)#18 matt986 says “RB, the number is an estimate, and HAS to come from the EPA test cycle.”
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It is not so clear that such is the case.
(1) There are no Volts yet to test.
(2) The EPA therefore has not performed any tests.
(3) The 2009 Honda Civic Hybrid is about 42 mpg on the combined cycle. There is nothing that will make the Volt better.
Someone else created the number. I don’t doubt that it was done is good faith. It may be a good projection under certain circumstances. But who? where? what?
Nov 16th, 2008 (12:29 pm)We can all debate the technicalities of how this figure is reached, but let’s face it, perception is everything. If the general public is introduced to the production Volt as the “100 mpg car” it will truly be a game-changer. I am still personally torn about the philosophy of the bailout, but for GM’s sake, I hope it happens, only because GM is showing a lot of promise with its future product lineup.
Nov 16th, 2008 (12:30 pm)RE #2 MarkinWI
On Long Island (utility is LIPA) we pay over $0.20 /KWh
The link you gave is a state wide average and there is no reason for up-state New York to pay the same as New York Metro, or Long Island.
Of course I don’t pay anything, since my place is net zero energy.
(www.netzeroenergy.org)
Nov 16th, 2008 (1:11 pm)#17 matt986
Statik, the reason you think 50mpg is not feasible is that you’re thinking about a gas engine driving the wheels through a transmission, a-la a traditional car. In that arrangement, it IS hard to get 50mpg.
An engine driving a generator, which in turn drives an electric motor can be MUCH more efficient than the above arrangement. If it were not, then trains would not use this arrangement.
Consider also, that the generator does not bear peak load – some energy is pulled from the battery under peak load, and gets replaced through a trickle charge, or regenerative braking. Thus the engine/generator is not doing all the work a traditional ICE powered vehicle’s engine does.
50mpg is very feasible. You just have to think about the engine in the correct context.
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I think I am thinking about it clearly. If 50 MPG in a 3500 pound car was feasible strictly by running a ICE to power a generator to power the car electrically (without use of mass electrical storage to augment it) why are not all cars on this principle?
Trains use this arrangement because of the benefits of scale and inherent efficiency of the system to pull massive weight.
As for the merits of regen, that does recapture about 15% of power in the city, but that math is already one of the main factors in MPG numbers of hybrids like the Prius.
There may be some added efficiencies along the way, I don’t discount that, but something like the Prius is also a clean 700 pounds lighter and has less cd…and is still coming up short at around 45MPG.
I just can’t see it. Again, we have nothing to go on to prove that this is possible, no example of it anywhere else in any production car. GM has released next to nothing on the details on ranges and MPG since day 1. How is it possible that the 40 miles/50 MPG has stayed so rock solid anyway since the car debuted in January 2007? Virtually everything else has significantly changed about the Volt program, how can these numbers not have fluctuated?
/as always time will tell though, we just have to sit tight I guess
Nov 16th, 2008 (1:31 pm)#10 DonC
How can you give a blended MPG number, and call it “very defensible and scientific way of coming up with a real viable number”? I just don’t get it. The only way you can combine a electrical value and a gasoline value is to first do cost of commodity conversions, then extrapolate the value in MPG.
I’ll give you a scenario.
I take the Volt out on test drive for the MPG calculation. I go 60 miles. The cost of the first 40 miles electric is $.90 (assuming around .11/kwh), going the extra 20 miles on gas costs $1.60 (with prices at $4.00/gallon). Therefore the blended cost is $2.50. Which translates to around 100MPG.
Now do the exact same thing, but now with gas at $1.75. It works out to be .90 electric + .70 gas, or $1.50 total blened cost or 70MPG.
That is the flaw. The current system is a exact science. It gives you what the car will achieve over a set driving condition every day of the week in any country in the world.
The blended number is inaccurate the second the gas price at the pump changes or the rate at which you pay for electricity changes.
Explain to me how this is not true? The number HAS to reflect both components seperately to be completely and scientifically accurate.
45/28 Electric Range (city/highway)
44/52 Gasoline MPG (city highway)
Maybe if you HAVE to have the blended number somewhere on the car window sticker, it can be in very small print in the lower right corner with a big asterisk (*) and disclaimer on it that reads:
“The number is only accurate assuming a price of $.XX/kwh electric and $X.XX price per gallon”
Regardless, I feel it is a very crude/deceptive way of measuring the Volt’s abilities and all the ‘kafuffle’ is just so that they can advertise the heck out of 100MPG.
If the iMiev beats it to market with a 100 miles/16kWh pack (10 usuable)…are you ok with them advertising a MPG of 360 MPG (based on $4 gas)? Why can’t they do the same ‘conversion’ to illustrate its value to the consumer? It is easy to see how ridiculous it could all get.
How come they don’t also do some kind of reverse ‘up front’ additional cost of the battery pack itself in the calculation. In that scenario the Volt would probably get a rating of around 12MPG.
Nov 16th, 2008 (1:32 pm)I will go out on a limb and say the day the EPA releases this number and their range calculations that the resulting commentary is more likely to be how the Volt does NOT get 50MPG and possibly how it does not get 40 miles electric on the highway under ‘normal’ use…and not the blended MPG number at all.
***********************************************************
Right now we only know what GM is saying…just like what other auto maker does with their new products…if in fact any does.
Why not wait till the EPA comes out with their figures and then if you don’t like the results, you can complain. I sick and tired of hearing you bitching about GM. Give GM a break!! They are down now and they do not need you to constantly bad mouth them.
Nov 16th, 2008 (1:35 pm)Trains use that system so they can apply torque to each wheel without complicated gear boxes. They need maximum torque to get that train moving. It is all about transmission of power.
I think GM deserves every bit of bad mouthing it gets. I am not sure if management or the unions messed them up worst, but the result is a real F*** Up.
Nov 16th, 2008 (1:40 pm)They’ve also stated repeatedly that weight has been a less important factor than aerodynamics for range.
This makes sense especially for crusing at speed, since weight has little effect on the force needed to overcome drag. Keeping a car going at 60mph requires only about 20 hp, IIRC.
The stops accrue energy through breaking, and the startups at still going to be done with electricity… likely with a little boost from the battery.
So I can easily see 50mpg.
Nov 16th, 2008 (1:41 pm)First, let’s be clear that Lyle left something out when he said the Volt “the car will drive for 40 miles on battery without gas”. As we’ve (sadly) learned here on this site is that the 40 miles in BEV only mode is city driving. And I assume that it assumes, to get that 40, that a certain amount of braking, and hence regen, is happening.
In any case, the biggest problem of trying to give an EPA mpg rating to any plug-in hybrid like the Volt is that lots of assumptions need to be made (even for gasoline only powered cars EPA ratings make assumptions). It’s like trying to fit a round peg into a square hole.
For example… Lyle writes (or reports):
“78% of driving would be expected occur in charge depleting mode”
So 22% is in charge sustaining mode. Assuming this was city driving (where the Volt should be getting 40 miles/charge), that’s a daily driving distance assumption of 51.26 miles. You drive more than that a day (or use the highway and so get less than 40 miles/charge) your “MPG” will be less, and similarly if you drive less it will be more.
I’ve been and still am in the camp that wants broken down data for plug-in’s, not a “boiled down” number loaded with assumptions. Ie. put on the sticker:
Miles per charge (broken down city/highway and combined cycle)
Miles per gallon once charge depleted (again broken down city/…)
Miles/kwh (again broken down city/…)
Usable battery capacity in kwh (8kwh in the Volt’s case)
Nov 16th, 2008 (1:46 pm)#21 igotzzoom says “… let’s face it, perception is everything. If the general public is introduced to the production Volt as the “100 mpg car” it will truly be a game-changer.”
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Saying “…perception is everything…” with the implication that the perception can somehow be divorced from reality is a bit like saying I can be divorced from my own shadow.
Maybe I can create an illusion for a few moments, and maybe GM can do that also for the Volt, but reality has a way of catching up pretty fast. After all, mpg is a hard number that many people can check and say what they found.
(I still don’t understand where the 50mpg came from.)
Nov 16th, 2008 (1:46 pm)don’t they have mules running and they can get the actual mileage from?
Nov 16th, 2008 (1:58 pm)#24 Statik
AFAIK they don’t do the electric –> gas equivalents in dollars, they do it in energy equivalents.
You have to realize the mpg number is needed for CAFE. It’s hardly a way to measure an EV. But the EPA has to have an mpg number in order to calculate CAFE so you’re going to get one. The number you’ll get will be valid though it may not offer guidance from a consumer standpoint.
My guess is that the more interesting information which you will need from a consumer standpoint will also be on the sticker. That would include the range, the miles/kWh or kWh/mile, and the mpg after the battery is exhausted. But for CAFE purposes the EPA needs the single mpg number
Basically stop thinking that the mpg number is for consumers.
Nov 16th, 2008 (2:03 pm)Casey,
Most of the time, mules are useless for MPG tests. The body is wrong, the software that in this case governs when the engine turns on is incomplete, and even in a normal car, engine efficiency in a mule is usually terribly lackluster as the software that deals with timing has not been perfected. While the mules are indispensable for getting this right pre-production, they won’t actually tell you anything about mpg till you get into the final pre-production Volts with full system integration.
On the other hand, this is great news! While the mpg figures are, to be blunt, pointless in this case, it will greatly help sales as people look in the window and see *110/100* mpg or the like. That figure alone WILL get a great many people to pay a premium over a Prius, no matter how tricky the actual situation is.
Nov 16th, 2008 (2:08 pm)#29 RB
The 50 mpg is an “about” number which Lutz has consistently thrown out. You’re right it has no real meaning but my guess is that’s it not totally off the wall. The Prius gets 48 mpg. Keeping in mind that if you’ve driven a Prius you know you can recharge the battery very easily, why shouldn’t the Volt be able to do the same or slightly better? All that has to happen is regen and a bit more DOD.
I’m not sure why you’re so confident that 50 mpg is impossible.
Nov 16th, 2008 (2:12 pm)#32 Grant – “While the mpg figures are, to be blunt, pointless in this case, it will greatly help sales as people look in the window and see *110/100* mpg or the like. That figure alone WILL get a great many people to pay a premium over a Prius, no matter how tricky the actual situation is.”
This seems too much like saying that defrauding and misleading consumers is a good thing. Even worse than Aptera’s just plain making up a 300 mpg number for their electric car.
Nov 16th, 2008 (2:17 pm)I think so too, giving any true MPG rating is misleading as it is a variable. However, it is very similar to what was done with the first few hybrids released. Remember when they spoke of 75 mpg for the Prius and Honda with no data to back it up? It is, in this case, a bit better thought out legally. Nevertheless, it is not accurate, and won’t be. It will still be good for sales.
Nov 16th, 2008 (2:45 pm)Statik@23 said in part:
“…I just can’t see it. Again, we have nothing to go on to prove that this is possible, no example of it anywhere else in any production car. GM has released next to nothing on the details on ranges and MPG since day 1. How is it possible that the 40 miles/50 MPG has stayed so rock solid anyway since the car debuted in January 2007? Virtually everything else has significantly changed about the Volt program, how can these numbers not have fluctuated?
/as always time will tell though, we just have to sit tight I guess”
So, by definition, we have no data that suggests that this groundbreaking technology cannot do all of the above – or more (g).
Be well
Tag
/1001 paper cuts…. plenty of time until July 4,2010
Nov 16th, 2008 (2:50 pm)DonC, yes, it’s the CAFE that matters for GM, and the whole reason they did the Volt program… we have to keep in mind that the main reason GM announced the Volt is because they didn’t expect to make huge profits from it… the whole idea is that for each Volt you sell, you can sell several high profit margin gas guzzlers and still meet the CAFE numbers. Makes very good business sense. The only problem is no one is buying gas guzzlers any more, or vehicles in general right now due to worldwide recession.
Grant… you can’t really compare this to the Prius or other Toyota and Honda non-plugin hybrids…. a non-plugin hybrid you can definitely compute the MPG exactly the same way as for a conventional vehicle… because ALL the energy used to move these cars comes from the gasoline you put in the gas tank. Some of that energy is simply converted:
stored chemical (gasoline) => (via ICE) kinetic energy => regen braking into electrical energy (battery) => (via electric motor) kinetic energy => ….
With plug-in hybrids you have two sources of energy and that’s what throw the monkey into the wrench for determining fuel economy numbers.
Nov 16th, 2008 (3:11 pm)Static # 24:
45/28 Electric Range (city/highway)
44/52 Gasoline MPG (city highway)
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Agreed, but we also need to know the energy used, which MPG provides. So, how about:
45/28 Electric Range (city/highway) on an 8 kWhr charge
44/52 Gasoline MPG (city highway)
JeffM #28 is close to this, but the above gives everything JeffM wants more concisely.
Blended MPG has little value for the consumer, but I can see how it will help GM CAFE, as DonC #31 points out.
Nov 16th, 2008 (3:11 pm)DonC, I agree with Static in that combined MPG is a lousy point of reference for comparing the Volt’s peformance to other vehicles. It only has meaning in conjunction with test parameters. As discussed ad nauseam in previous threads and on the forum, there needs to be EV only numbers and range extended numbers in order for consumers to be able to make reasonable comparisons.
GM, as Stactic pointed out, hasalways said 50MPG after AER. Whether this is feasible or not remains to be seen. I’ll take the fact that they, as Static also points out, have changed many other aspects from the concept but not this one as evidence that it is attainable. For further “proof”, I submit Prius hypermiler experiences. The Volt EFLEX drivetrain gives the engineers the ability to design in many of the hypermiler benefits without the need for driver skill or significant compromisizes in performance. This is possible because, contrary to views expressed about the battery being dead weight after AER, the Volt will still be a fully capable EV even after AER. The traction motor will still power the wheels 100% and the battery will still be avaiable to provide peak loads AND smooth out transient loads AND all power when enough excess energy from the generator has been stored. Additionally, this excess energy storage in the Volt’s “large” battery will allow for optimized cycling and ICE usage in low power driving such as in city driving and stop and go highway traffic. Hybrids like the Prius use something like 600-800W in their battery cycle and require the power of the ICE for many operations, including reasonable acceleration. This results in many more on/off cycles and much more revving up/down for changes in power demand.
The EREV is a much more elegent and in many ways a simpler solution. The only real obstacle is cost. Can the performance be optimized enough for enough users to overcome the added cost?
Nov 16th, 2008 (3:15 pm)#8 “I would like to know: City/highway all electric, city/highway all gasoline, and Kwh to fully charge the battery from customer depletion.”
#24 “The number HAS to reflect both components seperately to be completely and scientifically accurate.
45/28 Electric Range (city/highway)
44/52 Gasoline MPG (city highway)”
#21 “We can all debate the technicalities of how this figure is reached, but let’s face it, perception is everything. If the general public is introduced to the production Volt as the “100 mpg car” it will truly be a game-changer.”
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Some very good points made in this discusion. I think that for the consumer who educates themselves about EREV vehicles you really must break it into pieces like Bearclaw says in #8 above or statik in #24. I think you must know AER (both city and highway) and “standard” MPG (city/hwy) when running the ice after charge depletion, as well as the amount of electricy required to recharge the depleted battery. But igotzzoom brings up an excellent point in #21. If this vehicle is going to start the change towards electric vehicles for the masses it must get their attention with a MPG figure that is somehow comparable to what they are used to seeing, and I think it must be a number greater than or equal to 100 MPG. So I guess I’m advocating both methods, one for the educated consumer and one for the other, much larger, group.
Nov 16th, 2008 (3:21 pm)Don C
“AFAIK they don’t do the electric –> gas equivalents in dollars, they do it in energy equivalents”
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What the heck is a energy equivalent then, and how is it calculated? What value does it offer? What is its purpose if not to compare them monetarily? (emissions?) I honestly have no clue. Will there be a brochure and literature attached to give the average customer a background in how it is conceived? Will there be a detailed synopsis of how the number was calculated and under what conditions for each type of different electric/E-Rev vehicle?
Seems confusing to say the least. How does the average consumer use this ‘equivalent’ to do the math to get a reasonable economic value of cost of ownership?
Even Lyle in the article says this, “The Tesla it turns out, since it doesn’t use gas, is rated purely in kwh per 100 miles, 33|33 to be exact. This can be converted into gas equivalents, but the result is either 105 mpg or 256 mpg city, depending on how one does the calculation”
It is 105mpg or 256mpg depending how you do the calculation? What the heck does that mean…depending. 105 or 256? Pretty big difference.
Other than the ‘shock and awe’ value of 100MPG on tv commercials and print ads, I don’t see any value at all in it. I guess the bottom line is…how is this better to the consumer than this:
45/28 Electric Range (city/highway)
44/52 Gasoline MPG (city highway)
Can anyone explain how this blended, ‘gas equivalent’ system gives a consumer any glimpse at reality, as compared to a simple sticker that says, ‘it goes XX electric then gets XX MPG’? With a simple sticker I can estimate my average daily cost to withing pennies…the other way, I have no clue without digging around to find out the formula.
I conceed that I perhaps don’t understand this system at all, maybe there is some entrenched informational value that I can’t see, even after being on this site for 2 years and following EVs for a decade…but that is the flaw in and of itself. That is really the point I am trying to convey.
/KISS – my parents have no shot at understanding anything other than ‘ it averages 40 mile range electric first and then 50 MPG after’
(But I really am curious, I want to know. How do you calculate what 1 gallon of gas is to its ‘energy equivalent’ in electricity?) Is there a link to some ‘official’ conversion site you could forward me to, so I could play around with it/research it until I understand?)
Nov 16th, 2008 (3:27 pm)From my perspective, I could care less about how many MPGs the Volt gets with the ICE running. The bottome line is, it will go 40 miles without using a DROP of gas. That effectively means I could drive the Volt everyday for the life of the vehicle and get infinite MPGs… Put that on the window sticker!
Nov 16th, 2008 (3:30 pm)#38 Shaft
Agreed, but we also need to know the energy used, which MPG provides. So, how about:
45/28 Electric Range (city/highway) on an 8 kWhr charge
44/52 Gasoline MPG (city highway)
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Yes, I’m sorry, you are absolutely right, it does have to give the battery capacity to make sense. I forgot to add that.
/good catch
(that should be added in my post #41 too…can’t believe I forgot that, apologies)
Nov 16th, 2008 (4:03 pm)#41 Statik
You keep asking for consumer information. CAFE doesn’t really do this. I mean think about this: if a vehicle gets 15 mpg and GM makes the same vehicle that can only use ethanol then the ethanol only vehicle gets 100 mpg because you divide by .15. Does this make sense? Of course not. It’s just another subsidy for Iowa farmers.
You keep trying to make a CAFE calculation into something for the consumer. It’s not, though as a practical matter I think that trying to use dollar equivalents is pointless because electrical rates and gas prices are too different and change too rapidly for any real serious purpose. I think you and I generate our own solar. You can sell yours. I just give it away. So our costs of electricity are completely different.
Nov 16th, 2008 (4:17 pm)DonC,
I didn’t realize your original comments were considering CAFE. For that purpose, what you describe is reasonable and necessary. It’s purpose is to assign a “value” to the fleet’s operation as a whole, so a monolithic number can suffice if the proper assumptions are made.
Nov 16th, 2008 (5:13 pm)For a volt type vehicle, a simple way to describe mpg might be to simply measure the total miles you can travel on a full electric charge and 1 gallon of gas.
The volt would be: electric: 40 miles, 1 gallon of gas: 50 miles.
Total MPG: 90
Nov 16th, 2008 (5:14 pm)Just wait until the electic utilities decide that there is enough captive demand for charging EVs. Anyone want to bet that the cost per kwh will suddenly jump through the stratosphere, resulting in triple (or greater) price increases.
Just a thought to keep in mind for anybody who is looking at charging costs.
Ter
Nov 16th, 2008 (6:49 pm)Ter Meenal,
One can always intall solar. Why do you think charging your Volt will be any different of an economic scenario for the utilities than any other power usage in the home?
Nov 16th, 2008 (7:35 pm)Statik,
Are you clear that the battery is not dead weight after the AER is reached?
The battery will accept the energy of regenerative braking, and allow the IC engine to operate at optimimum speed and load.
Nov 16th, 2008 (10:30 pm)koz,
Question:”…Why do you think charging your Volt will be any different of an economic scenario for the utilities than any other power usage in the home?…”
Answer: Aside from a healthy dose of cynicism? Nothing more than sheer corporate greed.
Ter
Nov 16th, 2008 (11:29 pm)100 mpg?
That’s nothing.
Try another people’s car that gets 235 mpg and is slated for 2010 production (supposedly) — and it’s not even a hybrid!
http://carsworld.northglow.com/technology/come-2010-the-100kml-volkswagen-l1-will-hit-production/
http://www.rmcb5.com/forums/general-discussion/vw-l1-concept-235-mpg/
Nov 17th, 2008 (12:15 am)Ter Meenal, you must be new here??… first keep in mind that a lot (most?) States regulate electric rates and rate increases (or decreases) need to be approved by that State’s Public Utilities Commission. It has to be justified based on costs (with fuel costs being the biggest factor).
Second, BEV’s (including BEV hybrids like the Volt) will be mostly charged off-peak… ie. evening/overnight hours. All power companies have excess capacity off-peak because they built their power generating capacity to handle peak hours. As such, plug-in vehicles are a great untapped market for them to sell power off peak and put that otherwise unused capacity to work making money. It’s even better if the utility has lots of generation capacity that is hard to throttle up and and down (like nuclear for instance).
I think it’s estimated that current off peak excess capacity could recharge 10′s of millions of plug-ins before any new power plants would even need to be built to meet the demand.
Nov 17th, 2008 (10:25 am)Volt is the first American car that might be good enough for competition against all those Japanese cars. However, it is too late and might be too expensive which might wipe out all the savings on the gas. Plus, GM (and all American cars) are not that good on reliability. One expensive repair can make all these good deals nonsense. I will pray for American car companies but I will not buy their cars until their resale values are higher than those Japanese cars 10 years later.
Nov 17th, 2008 (11:44 am)1KWH = 3.6MJ (mega joules) = 860Kcal = 3412 Btu
There’s some energy equivalents for you.
Gasoline has an energy density of about 45 megajoules per kilogram (MJ/kg) or 8.76 KWH/liter.
Nov 17th, 2008 (2:00 pm)It wouldn’t surprise me a bit if it gets 50 mpg running in extended range mode because the ICE is running at optimal rpm all the time whether you’re waiting at a light or stopping at a stop sign, then you have brake regeneration when stopping helping out, and you have the efficiency of an electric motor actually moving the car. So, seeings how the Toyota Prius (under not so optimal conditions all the time) is getting 45 mpg, I would think the Volt could do 50 easy.
Nov 17th, 2008 (2:52 pm)“”"”I would prefer to see a miles/KW-hr rating, along with the size of the battery (ie: KW-hr storage capacity, and its expected range). Then, a separate mpg rating when running in gas mode. This makes it clearer to the average Joe, and allows them to better understand how this would affect his driving requirements”"”
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A sticker with three separate numbers, none of which tells the whole story by itself, would be the most useful for those of us who enjoy doing calculations. But “the average Joe” as cited above, will see two numbers which have no meaning whatsoever for him, and a 50 mpg figure. So his question will be, “why should I pay 10k extra for a car that is only 7mpg better than the Pruis.
In other words, the suggestion above makes it possible to calculate that the Volt can exceed 100mpg, but you have do make assumptions and do calculations to get this result. If you do not do the calculations, it looks like a 50 mpg car.
The Volt is intended to be a consumer product, and after the first year, a mass market product. You do not mass-market a product by providing raw data from which the consumer has to do calculations to arrive at the selling point.
And make no mistake, EPA milage stickers are marketing devices, mandated by the government to aid consumers who want to identify energy efficient vehicles.
Nov 17th, 2008 (4:13 pm)Well, if you want an estimate of how much gasoline that 78% means, then the Volt would obtain 230 MPG, which, oddly enough, is virtually the same figure that I calculated using commuting trip data
and then based the remaining mileage on total gas used. if the EPA folks are trying to factor in the electricity used, expressed as MPG equivalent, they are going to have problems. You cannot make equivalences based on respective costs of gas versus electricity – that has changed 100% in both directions over the past several years. So what’s left is energy equivalences or perhaps emissions, but what’s the purpose of that, exactly? That changes everytime you cross a utility’s operating area. Perhaps we’d better not confuse everything by trying to express something in terms of MPG,
under the false assumption that this would be clearer. How about miles per KWhr (MPKWH) , which is what should be reported and what consumers should be getting used to?
Nov 17th, 2008 (5:17 pm)MPG ? i don’t pay for hydro in galoons/ltrs ,
then how Volt expense in MPG ? may be it should be “kms per kw” or “mpkw”.
On the MPG side if you are thinking of gas, First the oil is converted to rotations and then to elcetricity and then back to rotations. Every thing will work smooth till we introduce “friction” “gravity” “conversion losses” etc.
I don’t know how 3 times conversion losses is lesser than one time conversion loss ( normal gas car ) and assuming it will be more efficient.
Ultimately what matters is how much i need to spend and how i can calculate to my expense.
Nov 26th, 2008 (5:31 am)I LOVE THE CONCEPT AND PLUS, AM AN ENVIRONMENTALIST SO THE CZAR BATTERY gODDESS CAN KISS HER HEIR!!!!!!!