Is the Chevy Volt Only a Fair Weather Car? 37 comments
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All this nonsense about the Chevrolet Volt's fuel use and performance is just hot air until the car is on the road and its actual performance under real driving conditions and with ordinary drivers is measured.
I propose a side-by-side test of the Prius and the Chevrolet Volt to settle which is the more practical and versatile car.
A friend of mine who lives in Saskatoon, Saskatchewan has driven a 2007 Toyota (TM) Prius, which he bought new, for the last two years.
He does not garage his Prius in the winter and told me last summer when I was visiting that during the winter of 2007-8 the air temperature in Saskatoon reached -30 fahrenheit on more than one occasion.
Nonetheless, he said, his Prius never once failed to start on any winter morning.
Yes, the Prius nickel-metal-hydride battery has a heating and cooling system, which drains some power from the battery to maintain it above a set temperature in the winter and below a set temperature in the summer, but his Prius has made it through two Saskatoon winters without a failure to start or operate.
I was in Yellowknife, Northwest Territories, Canada two weeks ago, and I noted that the Yellowknife Fire Department Chief's car is a Prius. I asked a lady fire captain who was driving the car if the department had had any weather problems with the car. She said "no" even on the day that yellowknife experienced an air temperature of -50 fahrenheit in the winter of 2007-8. Admittedly the car is garaged, but it was in use at -50.
Yes, I know that the Prius is a full hybrid with a gasoline fueled ICE and the Volt is an "extended range" plug-in hybrid (whatever that actually means), but I would never even consider buying a Chevrolet Volt until i know in what air temperature range it can be operated. I live in Detroit where below zero fahrenheit winters are common, and I think the Volt is a fair weather car.
I want General Motors to succeed, so i ask, politely, that a Chevrolet Volt and a Toyota Prius and, to be fair, a Ford (F) Fusion be run through their paces by ordinary drivers in a variety of climate extremes, road conditions, and road grades.
No matter how the EPA calculates MPG it won't matter at all if the car's range is small, or it won't function in extremes likely to be met daily by most drivers outside of southern California.
I really don't think GM's engineers have solved all of the basic problems faced by the Volt, and I think that all of the talk about fuel economy and acceleration is just to mask how impractical such a car is and what a tiny market segment it really has.
If I'm wrong just match it up now with existing EVs and let's see the results that prove me wrong.
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I see limited appeal for people who don't live in major cities.
My interest is purely in the battery side, since that is the area that I work in. As I previously stated, commercial cells will not operate with any meaningful perfomrance at such low temperatures. And conditioning the battery "for a few minutes" as Weber states, will do very little for a thermal mass of that size.
I have no problem admitting that my knowledge of the Volt is seriously lacking. What I do have a problem with is the lack of fundamental understanding of the everyday problems associated with a 16kWh battery pack.
On Aug 13 12:45 PM car_guy wrote:
> This would be true if the Volt operated the way that Jack keeps insisting
> it operates. However, contrary to Jack's repeated statements, the
> Volt's ICE powers a generator which powers the vehicle first, keeps
> the battery conditioned second, and then recharge the batter with
> any residual remaining power. In the article referenced by Purdone
> the GM engineer clearly states that if started in very cold conditions
> or even after sitting for a long period of time, the car will NOT
> start in electric mode but will instead start the ICE which will
> power the car and then condition the battery. For decades GM's durability
> testing program has included cold start after 24hr cold soak in their
> proving ground in Kapuskasing, ON on Hudson Bay. Rest assured that
> a number of the 80+ Volt prototypes will be spending the winter there.
>
>
> Your battery facts are accurate, but your Volt information is totally
> wrong.
In Prius you have a battery drive meanwhile you have power on them, after that point the ICE takes the total workload.
In VOlt as far as I know the ICE (a Sterling or similar) is always moving (at a regular RPM) producing electricity in a similiar fashion the service turbine in jets that supplies electricity to AC water etc. when the plane is not flying.
SO you have a electric generator feeding batts in a continuos way...a small no reciprocate engine producing a electric charge could get the 230 miles.....maybe.
I do not want to believe in GM doing an official number if they are not able to get it, they were working at the beginning with a 100 MPG number and now is 230.
Insulating and refrigeration now days is a matter of cost is not a technical issue.
Regards
On Aug 13 01:36 PM billddrummer wrote:
> My problem with the Volt is its range. In my experience, very few
> people commute less than 40 miles/day. It's more like 75-80.
>
> I see limited appeal for people who don't live in major cities.
The batteries are always a big deal with these types of vehicles. The Volt will initially have separate heating and cooling systems to manage the battery pack and it will operate within a range of 50%-80% charge to maximize pack life. Battery life and cost is the #1 issue with this car so it reasonable to assume that in the extreme weather conditions described in this thread that the vehicle will use the ICE/generator for propulsion until the battery pack is at proper temperature and charge. GM is planning to put a 10 year 150,000 mile warrenty on the battery pack and powertrain so they need to make it last.
On Aug 13 02:08 PM MRTTF wrote:
> My concern, from a technical standpoint, isn't the Volt data. It
> is strictly from a battery standpoint. I am pretty sure that my knowledge
> of the Volt is not entirely right. However, if the ICE is powering
> the vehicle, than why all the hype about how the ICE only is there
> to recharge the battery?
>
> My interest is purely in the battery side, since that is the area
> that I work in. As I previously stated, commercial cells will not
> operate with any meaningful perfomrance at such low temperatures.
> And conditioning the battery "for a few minutes" as Weber states,
> will do very little for a thermal mass of that size.
>
> I have no problem admitting that my knowledge of the Volt is seriously
> lacking. What I do have a problem with is the lack of fundamental
> understanding of the everyday problems associated with a 16kWh battery
> pack.
>
> On Aug 13 12:45 PM car_guy wrote:
Taking you at your word, that "I want General Motors to succeed", your poor impression of the Volt comes from a complete lack of understanding of how the vehicle actually works. You are confusing the marketing terms and language with the actual engineering concepts used for these vehicles.
A hybrid vehicle is one that has both an ICE and electric motor used to propel the vehicle and that has the ability to run in electric only mode. A hybrid does not need the ICE to mechanically drive the wheels. Feel free to show me any 3rd party definition for hybrid that requires this.
The Volt is a serial hybrid vehicle. It has a gas ICE that runs an electric generator and electric motors at the drive wheels. There is no mechanical connection between the ICE and the wheels. The Prius is a parallel hybrid where either the ICE or electric motor can directly power the wheels. It has a very complicated software package and transmission that switches between the 2 engines based at low speeds. There are also 2 mode hybrids which are parallel hybrids that use electric motors in the transmission to proivde all electric drive at low speeds and electric assist at high speeds. The Prius does not provide significant assist above approx 45 mph which is why the city and hwy mpg numbers are almost the same.
Serial hybrids are much more efficient designs because they avoid all of the mechanical linkage to the wheels including the transmission. However, they require very high energy density batteries to work. These did not exist in the mid '90s when Toyota began development on the Prius so they invented the parallel system to enable low speed electric driving with lower energy density batteries. A brillant piece of engineering that solved that mid '90s battery problem.
Just because the Volt's ICE is not mechanically connected to the wheels does not mean that it cannot drive the wheels. The Volt has a 1.4L ICE which is much bigger than it would need to only charge and condition the battery. This engine produces enough electricity thru the generator to fully power the car w/o the batteries. In this mode the Volt runs the same way all train locomotives have run for the last 50+ years. When the engine comes on it's lowest priority will be recharging the battery because that would put excessive load on the engine and is not very efficient or necessary. The battery is meant to be recharged with the plug when the owner returns home, assuming they drive less than 300 miles in a single day.
Lastly, let me break down the marketing term "extended range plug-in hybrid". Plug-in hybrid simply means that the battery pack can be charged using the grid instead of the ICE, which is much more cost effective and possibly cleaner depending on where you live. Extended Range is in reference to the fact that the vehicle works exactly like an electric car for a period of time/distance but the ICE provide EXTENDS the range another 240 miles.
GM already has 60 prototypes built off of production tools and is busy performing final validation testing. They are also letting journalists drive the prototypes which is almost unheard of because fit, finish, and even performance of prototypes can be very rough depending on how well the program is going.
Typically side by side test are done with actual production vehicles. Auto makers, including Toyota build and test prototypes to validate and refine their designs. Since software has a significant impact on hybrid performance, production vehicles should exceed the performance of the prototypes. Your demand for an immediate face off simply reflects your lack of knowledge of the process. Unless you were suggesting a face off between the Volt and the plug-in Lion Prius....
See below for the mileage explanation.
On Aug 13 03:00 PM Advill wrote:
> Perhaps I´m wrong but the basic difference between Prius (or alike)
> and Volt IS THE WAY IN WHICH ELECTRICITY IS USED.
> In Prius you have a battery drive meanwhile you have power on them,
> after that point the ICE takes the total workload.
>
> In VOlt as far as I know the ICE (a Sterling or similar) is always
> moving (at a regular RPM) producing electricity in a similiar fashion
> the service turbine in jets that supplies electricity to AC water
> etc. when the plane is not flying.
> SO you have a electric generator feeding batts in a continuos way...a
> small no reciprocate engine producing a electric charge could get
> the 230 miles.....maybe.
> I do not want to believe in GM doing an official number if they are
> not able to get it, they were working at the beginning with a 100
> MPG number and now is 230.
>
> Insulating and refrigeration now days is a matter of cost is not
> a technical issue.
>
> Regards
You also seem to convienently drop the term City mileage from your discussions of the 230mpg discussion. GM has not released any highway mileage estimates but has said they expect combined mileage to be 100mpg or above. This means that highway will be well under 100mpg which is logical because the vehicle will be using the ICE for power, not the batteries, much sooner in the cycle.
The city cycle keeps speeds at 45 mph and under and is limited to approx 50 miles. This maximizes the Volt's electric only distance. If the Volt gets 50mpg when using the ICE and only uses it for the last 10 miles of the test it would use 0.2 gallons of gas. For the 50 mile cycle using 0.2 gallons of gas would result in a 250mpg rating. Adding full loads for a/c and more aggressive driving makes the 230 mpg rating reasonable.
GM didn't design the test. Toyota gamed the test for years and the incredibly high mpg numbers for the early Prius vehicles led to the redesign of the test cycle. At $2.50 gas no hybrid, including the Prius makes any econonmic sense.
If I fill my tank, my range in normal mixed driving is 350 miles, give or take. Average mpg is in the mid-30s.
If I don't fill it, but just throw $5-$10 bucks in every 3 days, I can go indefinitely.
I consider myself a 'normal' driver (mixed highway/city, short trips account for 40% of total trips, drive about 1,400 miles/month).
Oh, and my car cost less than half the sticker price of the Volt.
I'll stay with 100% gasoline power, thank you very much.
There is such a long warrenty on the battery because it probably won't last. No one will pay $40K for a Volt only to have to replace a $10-15K battery after 3-4 years out of pocket. We have batteries and cells that have been on test for multiple years, but in a controlled setting. Without 10 years of real world data, I can't swallow that the battery will last 10 years.
Advill--Insulating and refrigeration now days is a matter of cost is not a technical issue.
This arguement does not work. From an engineering standpoint, maybe, but it will take several hours of gradual warming and/or cooling to get a pack of that size to a relative uniform temperature (+/- 3-5degC). If the pack is not uniform in temperature, you shorten the pack life very quickly and increase the safety rish associated with it.
'Nonetheless, he said, his Prius never once failed to start on any winter morning.
Yes, the Prius nickel-metal-hydride battery has a heating and cooling system, which drains some power from the battery to maintain it above a set temperature in the winter and below a set temperature in the summer, but his Prius has made it through two Saskatoon winters without a failure to start or operate.'
In other words, the NiMH battery would not work in very cold temperatures any more than a lithium battery.
However, Toyota engineered around it's poor cold weather performance.
Your statement therefore has nothing to do with the battery technology, but assumes that the engineers at GM are not competent.
Quite an assumption to make, without any evidence at all.
i respect your practical, savvy mental approach to this unknown/unproven piece of information.
when will we hear the results/assessment from Thor Lake/rare earths?
I APPOLOGIZE FOR THE SPELLING ERROR IN YOUR NAME.
In answer to your question:
Is the Chevy Volt Only a Fair Weather Car?
Sure, it will have to have a battery heating and cooling system just like the Prius or it won't work in northern climates.
I don't think GM engineers are quite that stupid.
Regarding the mileage claims for the Volt- the GM marketeers are just playing the numbers game with the mileage procedure that OUR OWN TRUSTED FEDERAL EPA has issued.
The GM folks should realize the backlash when the Volt hits the streets and blaming the EPA won't cut it.
There's not excuse for the lame EPA. They should take their Fed pensions and go home.
Nice discussions and explanation.
I only disagree on one point:
"Serial hybrids are much more efficient designs because they avoid all of the mechanical linkage to the wheels including the transmission."
Serial hybrids have to do the inefficient electric / mechanical conversion twice. ICE to generator, then electric back to mechanical at the motor.
This indicates to me that on a flat track, single highway-speed run, where the batteries have discharged to min level, the parallel Prius may come out ahead of the serial Volt in mileage.
The main advantage of the serial hybrid drive train is it's simplicity over the parallel hybrid. I'm surprised that GM is hinting at such a high purchase price.
Also, as I think you pointed out, although both can run off the ICE only, a serial hybrid can be set up to run without batteries (like a locomotive -- ICE to generator to electric motor). So if the Volt batteries are frozen solid, it should still get you home. I don't think a Prius can handle this.
Keep in mind when you speak of a storage battery freezing solid that such a device is a mixture of manmade materials, electrodes of graphite or titanates, liquid electrolytes or semi-solid ones (electrolytes to work in the real world must have high throughput of ions, so that even so-called "polymer electrolytes" are not rigid solids where ions exchange by susbstitution but are pathways with minimal need for free liquids), and outer cases in which the battery's constituents are placed in sharply defined relationships to one another. Don't forget the parts and channels for the battery's internal temperature maintenance system. Valves for these systems can be irrepairably damaged by freezing.
When such a system as a lithium-ion or nickel metal hydride battery storage battery "freezes" mechanical motion occurs which has random elements so that upon returning to "operating" temperature the best that can be hoped for is that the structural integrity of the "system' has survived; the spatial relationships will not have.
Such a battery, once frozen, is ruined, and if it has ruptured, may inflict damge on the mechanical components of the power train. If such a battery has been used for SLI purposes then the vehicle's ICE will not be able to resume functioning even when returned to operating temperature for normal starting.
A frozen Volt battery will surely mean that the Volt has become a large wind break and certainly not a means of transportation.
At what point in the Volt battery system's discharge do you think the energy remaining above minimum capacity will be devoted to the heating/coolong system? It would be nice to know.
Granted when just about any battery freezes, it's toast (although I keep my alkalines in the freezer for shelf life).
I considered including the Volt would need an SLI battery to get you home with a frozen main Li-Ion pack, but I thought it's obvious.
I would ask your Canadian friends how the battery climate control self preservation system works on their Prius (Prii? Priuses?). It's an engineering problem that's been solved already.
In fact, since the Volt is a plug-in, it's less of a problem since it will probably be on charge when the extreme conditions occur.
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