Chevy Volt EV range and fuel economy updated
The Volt's lithium-ion battery packGM finally confirmed that the Chevy Volt will utilize an 8 gallon fuel tank to supplement the Volt's EV range.
So, what does that mean for the Volt's real world range and fuel economy?
Once the lithium ion battery pack drops down to 30 percent of its full charge, then the 1.4 liter engine begins generating electricity to power the Volt. The battery, however, is never recharged in this state. Still, in this state the Volt can travel at least another 300 miles, and then the battery has to be recharged. That will take about 8 hours at 120V, although a special 240V supply could drop that charge time down to about 3 hours.
But that won't matter as long as you only drive 40 miles or less, right?
Not necessarily. According to the latest reports, "Most people will get less than 40 miles. " And, once electric range is used and the Volt is dependent upon its gasoline engine, the Volt's city fuel economy will probably be around 38 mpg.
posted by Dahcredyns at
8:25 AM
21 Comments:
38 mpg city?
That a significantly less than what we've been led to believe up until this point. Most discussions have asumed the Volt would get 100 mpg when the gas engine is running.
To verify the mileage we'll need to know the following:
1. How many miles you can drive on one KWH in a volt. (Tesla = 4.7 miles/1 KWH)
2. How many KWH's of charge can be produced from one gallon of gasoline by the Volt gas engine.
This is a very misleading article. I don't have a dog in this fight but let's be fair...
1. You will never get stranded by the side of the road with the Volt. The gas engine keeps the battery pack at about 30% charge...as long as you keep filling the gas tank. So if I want to drive to the mountains - no problem.
2. About 80% of Americans commute less than 40 miles. That's both to and from work. Twenty miles each direction. For all those folks, the Volt will cost a couple of penny's per day to charge. If you go further, the gas engine kicks in, keeps the batteries about 30% charged as long as you keep filling the tank or until you get a chance to plug the thing in.
3. If you run about 40 miles, you use no gas. If you extrapolate that over a month working 5 days a week that's over 800 miles per gallon. If you take that over 10 months it's over 8000 miles per gallon. You see, you don't think about the MPG, it will be more like MP KW/hour. If you do go over the all electric mileage, you calculate the total gasoline used over the total mileage traveled. Let's say you used 10 gallons over that 10 month period. That reduces your mileage to 8000 miles / 10 gallons = 800 mpg. You cannot calculate just the mileage when in "range extending mode" (when the gas engine is running to keep the batteries at 30% charge). That would be goofy. It would be completely ignoring all the distance you traveled using cheap power from the grid.
Now I'm confused. When I think of Miles Per Gallon [MPG] I think of it as a measurement with no time involved.
Using the Volt as an example, if I never drive MORE THAN 40 miles at ONE TIME or the gasoline engine never starts then it doesn't make any difference If I drive 10 miles or 10,000 miles. If the gasoline engine never starts I am getting infinite mileage per gallon regardless if I drove it all in one day or in 10 years. Infinite because I never use any gasoline.
However any time the engine starts and I drive some distance then I divide the miles driven by the gallons of gasoline used to get the miles per gallon. Miles divided by gallons = Miles Per Gallon.
I also found the article somewhat confusing. It says the battery is maintained at 30%. Does this mean the gasoline engine shuts off at 31% or 35%? Or does the gas engine continue to run at some slower or idle speed just to maintain the 30-35% if very little power is being used?
I understand there is no need to have the battery more than 30% full since you are going to take the car home and plug it in. So I guess the gasoline engine:
1. Either idles or varies it's speed say between 1,000 and 2,000 RPM to just trickle charge the battery during low use conditions, or;
2. Turns off and on like other hybrids, or;
3. Runs at a constant speed of 3,000 RPM or whatever the most economical charging speed is and then shuts off?
Only have a couple of hundred more questions but they can wait until tomorrow, LOL
Smurf - were you expecting the Volt - powered by a gasoline engine to get 100 mpg in the gas-engine-alone mode?
Why would you think that?
Name one car that right now - gets 100 mpg on a gas engine?
Is there a thought that all things equal...
a gas engine that is generating electricity - will get more MPG than a gas engine of the same size directly powering the vehicle without an intermediate electric motor?
Let's assume this (and it's probably a wrong assumption).
Let's assume that for ANY gasoline engine that if you make it power an electric motor instead of directly driving the wheels through a transmission/drive train - that it will get better mileage?
If that were true - then wouldn't we just replace all basic ICE engines with ICE slave engines that power an electric motor?
We need some clarity here. right?
Neil-
Sure, you will never get stranded on the side of the road in a Volt, you won't in a Prius or a Chevy Cruze either. So, you have to ask, what is the Volt really offering for a $40,000?
If the Volt, for instance, costs about as much as a Prius to fuel per year, as suggested by Edmunds, then why would most consumers pay so much extra up front?
The fact is, they probably won't.
It's not about the Volt, it's about reality. Since the Volt's future cost-effectiveness is based on scale, how do you sell such cost-ineffectiveness to millions of American consumers? And, even after a $7500 tax credit, it will still take millions of sales to move the Volt beyond the same niche the Prius is stuck in.
Likewise, get real about your math.
Sure most consumers drive less than 40 miles per day. In fact, according to the latest plug-in research, most probably drive less than 20 miles per day or trip. Yet, regularly, they drive more than this, which makes up the 12,000 - 15,000 mile per year average, otherwise the math doesn't add up. Maybe it's once a week. Maybe its every other week. Nonetheless, many drivers regularly drive more than 40 miles some of the time, and such driving makes up a large number of total yearly mileage.
In these driving conditions the Volt will not be very cost-effective.
Finally, there have been studies that have tested plug-in drivers. After 1 million miles of testing, it was found that forgetting to plug-in was VERY common.
For the Volt, forgetting to plug-in will have very damaging effects on fuel economy, especially if 40 miles is not real world average range. And it's not just mountain driving. Warm weather, jack rabbit starts, etc. will be the problem, not mountain driving.
In fact, some battery experts have claimed that less than 20 miles of EV range might not be that uncommon for many Volt drivers.
So, if the Volt costs about as much as the Prius to refuel per year at 40 miles of EV range? What happens if real world Volt range is 35 miles, or even 30 miles or less?
I'm doubting that the Volt comes to market in any significant numbers.
but does anyone have any answer to my question?
Here it is again:
Given two identical cars each with an identical ICE engine but one car has an electric motor powered by the ICE and the other one is a standard ICE-powered drivetrain...
which of the two cars will get the better overall gas mileage?
There are a few cars on the market where the same model comes in standard and hybrid flavors.
Do the Hybrid flavors get better overall MPG?
I know.. this is a dumb question... exposes more of my ignorance.. but I'll bet there are lurkers wondering also.
If I can buy a plain vanilla Honda or the same model but powered as a Hybrid - what are the reasons that I would get the Hybrid version?
well, there are different kinds of hybrid powertrains, and the answer can be a little different for each.
in general, however, the hybrid version will still provide better overall fuel economy. if, however, you are a heavy highway driver, then the fuel economy probably isn't that much better.
if you drive in congestion, city drivng, stop lights, etc., then the hybrid can provide significantly better fuel economy, even up to 50 percent or more.
the Volt and the Chevy Cruze, for instance, will share the same engine. if its true that the Volt achieves 38 mpg after the battery range has been expired in the city, that's still much better than what the Cruze will offer in city congestion, around mid-twenties i think. on the highway, GM had indicated it would be 50 mpg after EV range. the cruze would be about 40. so that still seems good, in terms of pure fuel economy.
Dach - where does the increased mileage come from?
Is it simply because the engine is turned off at stops?
All things being equal - two cars -both with standard ICE but one cuts off every time it stops - is that the source of the improved city mileage?
so.. then... having a standard ICE engine drive an intermediate electric motor that actually powers the car is not more efficient than a direct ICE to wheel ( without intermediate electric motor)?
I'm asking.. I don't know.
I know that some of the newer ships both military and civilian have done exactly that.
They now propel the ships with electric motors - which has an additional benefit in that the unipod propeller assemblies can rotate (since they no longer have drive shafts).
I'm pretty sure Diesel-Electric locomotives work the same way.. the Diesel engine powers an electric motor which then drives the wheels.
Tom,
www.gm-volt.com
GM uses what I'm sure is a fairly involved algorithm to determine engine RPM on the Volt. From your list of options, I believe 1 and 2 are more likely than 3, but who knows. Here's a post that describes some of their thinking and the constraints they are using:
http://gm-volt.com/2009/11/23/engineering-design-and-efficiency-of-chevy-volts-generator-mode-builds-on-gms-two-mode-hybrid-technology/
But in terms of MPG, I'm of the mind that thinks that gallons per month/year is the relevant issue. Sure MPG is an interesting metric and it is our normal rule of thumb to estimate gas usage. But the Volt is a whole other beast, with highly variable, discontinuous MPG states. That is a good excuse to drop MPG and focus on the real issue of total gallons of gas burned.
" That is a good excuse to drop MPG and focus on the real issue of total gallons of gas burned. "
perhaps but if you're trying to convince a prospective buyer - how do you "sell" this?
Most folks are going to say something like " okay.. cut to the chase - when will I break even?"
wrong?
alcatholic-
I completely agree with you. In my opinion, as far as all plug-ins are concerned, a new metric needs to be established. Perhaps multiple metrics.
Ultimately, despite the negative cost-effectiveness of probably most plug-in vehicles, plug-ins are the future, or at least an important part of the future. As a society, we must figure out a way to make these vehicles cost-effective (Of course, if we think long term, I think all plug-ins are cost-effective today, but that's a different story).
Unfortunately, and fortunately, plug-ins will be a niche market with plenty of early adopters waiting to buy. Thus, we need to move beyond using plug-ins as a marketing tool and more towards building the data that will help automakers, policymakers, etc. develop a cost-effective vision of a new, clean energy future.
Don't forget that any time you have a battery you also get the benefit of capturing the cars kinetic energy during braking.
Also, regular hybrids use the batteries and electric motor to help drive wheels during the least efficient portion of the ICE engine RPM curve, acceleration.
So, conceptually, regular hybrids have three main benefits that I understand. Engine stopping, battery storage of kinetic energy, and battery/electric motor use during acceleration.
The Volt concept (engine never directly drives the wheels) adds a fourth benefit. In addition to the the engine not being used during acceleration, the engine can be tuned to run within it's most fuel efficient RPM bands.
That's my mental model of the systemic efficiencies at this point. I haven't really investigated the more detailed mechanical efficiencies.
Larry-
regarding cost-effectiveness, I agree with your last post as well. consumers, policymakers, etc. need to get real about real goals. this isn't political fantasy island we live in.
anyway, back to your hybrid question.
NO! it is not all about start/stop technology. toyota, for instance, has developed very sophisticated software for managing not just start/stop, but regenerative power, etc.
again, unfortunately, each hybrid powertrain is different, so generalizations are becoming harder and harder as new hybrids hit the market.
still, to spin your point another way, there is no reason that start/stop technology shouldn't be used in EVERY single vehicle on the US market today. it pays for itself without any question, and more and more automakers are using this technology in more and more vehicles. it is destined to become standard.
my question would be, why hasn't it already been standardized? because, when push comes to shove, fuel economy still is not a driving force for the US auto consumer.
"perhaps but if you're trying to convince a prospective buyer - how do you "sell" this?
Most folks are going to say something like " okay.. cut to the chase - when will I break even?"
wrong?"
You're right, Larry. If a buyer needs to be sold, she'll want more MPG data. Maybe it would even be beneficial for that buyer to wait for real world data from a community MPG tracking website....I can't seem the one I'm thinking about at the moment. It was the first website that proved to me that the Prius was getting 48 MPG in the real world. Dahc do you know the websites I'm talking about?
like this:
http://mpgtune.com/?gclid=CI3eq9aOtp4CFYJx5Qod8CZUog
?
geeze.. do we need a website to calculate mileage?
Prius owners don't compute mileage the regular way?
I just keep a little notebook and a solar calculator and fiddle with it whenever I buy gas...
It's a simple calculation if you just write down your OD/miles and gallons every time you get gas - no?
Oh, I see you didn't understand. Let me explain.
The purpose of the website is to aggregate data from many users over time...you know, create a bigger data set for a specific car model to get a nice, robust real world MPG number. For something a variable as the Volt MPG, with as theoretical an EPA rating, a big dataset of real world use will be interesting.
mpgtune.com is not the one I was thinking about, but it will serve the same purpose if it has enough users.
Ah, found it!
Here's the mileage database I was talking about:
http://www.greenhybrid.com/compare/mileage/
okay.. I see what you're getting at...
most seem pretty close to their EPA estimates though
alcatholic said..Ah, found it! Here's the mileage database I was talking about: http://www.greenhybrid.com/compare/mileage/
alcatholic: I am going to change your name to the 'link master' LOL
Lots of good stuff coming from those fingers today.
Tom G.
Another subject - I also see some type of electric vehicle as our future. There will be several different types and strategies but they are the future and for lots of different reasons.
We can not expect gasoline to continue to be $2.50 - $3.00 gallon much longer because:
1. Oil supplies will tighten and prices will increase.
2. Global demand will increase causing general increase and conflicts will cause periodic spikes to even higher levels.
3. More gas taxes will be added to help pay for highway repairs and maybe even to help pay down the national debt.
4. More gas taxes [in the form of production taxes] will be added in the form of Cap and Trade/Carbon reduction taxes, and;
5. Everyone here on this blog will be way ahead of everyone else since we will all be driving hybrids by then LOL
It is also my guess that $5.00/gallon gasoline is not all that far away.
with regards to the gas tax - I don't think much will happen.
The gas tax - as a robust revenue stream only "worked" when gas was cheap and cars got crappy mileage.
As cars got more efficient, we bought less gas - ergo less gas tax.
If you increase the price of gas - people will drive even more efficient cars - which means even less gas tax generated.
People will buy more efficient cars - no question - and the higher the price of gas/gas tax - the more efficient but anyone can get a pretty efficient car ..like a Yarus or Civic or in a couple of years a Nano and not have to buy a hybrid.
right?
I think Dach has uttered these thoughts before - that the price of hybrid technology will have to come down to make it a more competitive, more tempting choice - especially for the folks who count their pennies.
Now.. I can see there being a tremendous market for high quality used hybrids - "high quality" meaning they have a good repair record and not a history of problems.
I haven't even done a cursory look for used Prius.. are they hard to find?
www.toyota.com !!
Certified used Prius central. I've been looking at that site over the years. Prices are in the $16,000 to $20,000 last time I checked. Fairly good selection.
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