GM Volt Webchat Transcript from 2pm 4/29/2010

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sjfotos

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Listed below an article and webchat transcript on the GM Volt from 4/29/2010

http://green.autoblog.com/2010/04/29/gm-hosts-ev1-volt-talk-with-chelsea-sexton-today-2-p-m-edt/
 
I'm having a real problem with GM's marketing trying to turn a HYBRID into an EV... And this from a company that should know what an EV is... :(

Thanks for the link Steve - I enjoy Chelsea's view of the world.

I loved this:
Do you have any thoughts about how the EPA should require the mileage/efficiency/fuel cost of EVs including the Chevy Volt be shown on window stickers and/or advertised?

chelsea: It's a sticky issue, but my main concern is coming up with a metric that can be used to easily compare against gas cars too. Historically we've seen that consumers aren't just comparing EV to EV, but also (more so, often) EV to gas cars. So we need something that is easily understood and translates across fuels. But we also need consumer education to temper the expectation that everyone will get the mileage shown on the sticker. Doesn't happen on gas cars today, but EVs really get nailed for it.
 
Mark the ICE, Hybrid, and EV the same way:
EV operation mode, if any: 4.8 mpe (miles per edie) and a useful 18-edie battery
(4.8 mpe x 18e)

ICE (charge-sustaining) mode, if any: 50 mpg and a 10-gallon tank
(50 mpg x 10g)

Not difficult to test or understand, right?

None of this "400 mpg" for a 40 mile trip with a plugin hybrid that gets 40 mpg and 36 miles on a 10-edie charge. (36 miles, no gas, then 4 miles on gas uses 0.1 gallons, giving 40 miles on one-tenth gallon, or 400 miles per gallon)

Just a simple, easy-to-compare:
40 mpg x 8g + 3.6 mpe x 10e
(shorthand: 40x8g+3.6x10e)
Range: 320 + 36 = 356 miles
 
AndyH said:
I'm having a real problem with GM's marketing trying to turn a HYBRID into an EV... And this from a company that should know what an EV is... :(
And I'm having a real problem with people that can't understand the difference between a hybrid and a dual fuel car. A hybrid gets all of it's energy from petroleum. A Leaf gets all of it's energy from electricity. A Volt can get all of its energy from gasoline, or can get all of its energy from electricity -- so long as it doesn't go too far without being plugged in.

So a Leaf has an AER of 100 miles and a Volt has an AER of 40 miles. That's a good argument for saying a Leaf is better than a Volt, but it's not a good argument for claiming a Volt can't be an EV.
 
Saying gas, plug-in-electric hybrid, or ICE-EV hybrid might be more accurate, but "gas" and "ICE" might not be popular words to use in advertising at this time.

So, they are either "knpwledge-challenged" (unlikely), or they have a reason for the "imperfect" description (more likely), and do it to intentionally mislead or distract readers.

For example, what might their reason be for claiming over 200 mpg for the Volt?
 
I think they have (wisely) backed off from saying that. It was a ridiculous claim that basically assumed they could get electricity free, that everyone drove an "average" number of miles, and that electric power plants never used fossil fuels.

Perhaps someone pointed out to them that using the same logic Nissan could claim to get more than a million miles per gallon.
 
In the hybrid EV industry it has been common to claim inflated "mpg" for a carefully-chosen (but non-standard) trip.

Although technically true, this "mpg" is of very little practical use, since varying the "trip" can (usually) create any "mpg" figure one wants.

A more meaningful "mpg" would be the mpg for the "charge-sustaining" part of the trip (on a standard ICE test circuit). Then, adding a Plug-In EV-mode range (or "miles-per-kWh") on the same test circuit gives a much more usable "standard" description of a PHEV's capability.

These few figures are easy to obtain using the existing test "cycles", and they allow an easy, meaningful comparison with many other vehicles, including most EV, ICE, Hybrid-Electric (HEV), and PHEV, just as the "sticker" mpg numbers now allow for ICE vehicles.

There is no need for a mysterious new unit of electrical energy called the "gallon-equivalent" ("ge"), usually found in the term "mpge". But, if "someone" insists upon it, define it as some simple, well-known, easy-to-use constant, perhaps like 5 kWh = 1 "ge".

We fuel ICEs in gallons and pay per gallon, but "fuel" for EVs is usually measured, and paid for, in kWh. There is no need for another unit that is difficult to relate to kWh.
 
planet4ever said:
AndyH said:
I'm having a real problem with GM's marketing trying to turn a HYBRID into an EV... And this from a company that should know what an EV is... :(
And I'm having a real problem with people that can't understand the difference between a hybrid and a dual fuel car. A hybrid gets all of it's energy from petroleum. A Leaf gets all of it's energy from electricity. A Volt can get all of its energy from gasoline, or can get all of its energy from electricity -- so long as it doesn't go too far without being plugged in.

So a Leaf has an AER of 100 miles and a Volt has an AER of 40 miles. That's a good argument for saying a Leaf is better than a Volt, but it's not a good argument for claiming a Volt can't be an EV.

Fair enough.

Here's one example from the Argonne National Laboratory: "Test Procedures and Benchmarking: Blended-Type and EV-Capable Plug-in Hybrid Electric Vehicles"

And one from the Department of Energy: "AVTA Electric Drive Vehicle Testing Activities & Infrastructure Requirements - NAFA (March 2010)"
DOE_BEV.jpg

DOE_HEV.jpg

DOE_PHEV.jpg


The EPA and labs have been trying to refine the methods of modeling the emissions and economy characteristics of PHEV for a while. The lack of solid standard is what leads to the giggles when a company claims what appears to be an outrageous fuel economy number.

I'm not judging or labeling 'better' or 'worse' - but if it's curved and yellow I'm not calling it an apple, either. ;)

Andy
 
Curiously you listed three of the four classifications used by the Department of Energy, and failed to list the fourth:

Extended Range EVs (EREVs)
• EREVs have an onboard battery and an ICE as the second energy source
• Operates in series mode: ICE charges the battery and the battery powers the electric motor(s)
• Normally will operate in all-electric mode until battery is discharged, then ICE turns on to charge the battery.
- No propulsion energy goes directly from the ICE to the vehicle wheels
• Must be plugged into the electric grid to fully recharge and balance its propulsion battery
• Captures energy during regenerative braking
• Examples include the Chevrolet Volt and Renault Kangoo(2003 model)
• Similar advantages and challenges as PHEVs
I suspect, Gary and Andy, that you may (perhaps unconsciously) dismiss this as a separate class because of that final bullet. Let me acknowledge up front that the "challenges" (I would say disadvantages) of PHEVs and EREVs are similar. The Department of Energy lists:

PHEV Disadvantages
– Cost, complexity and added weight of two powertrains
– Higher initial cost
– Drivers adapting to dual-fueling scenario
– Component availability: batteries, powertrains, power electronics
In particular, I am leaning toward a Leaf over a Volt because of the first two disadvantages.

The advantages are also conceptually similar, though in practice EREVs will have a higher AER than PHEVs. However, a PHEV cannot claim to operate in AE mode under all conditions until the battery is depleted, while an EREV can. This is a key point for me, as I often make 10-20 mile freeway trips, and I really do want to avoid using petroleum.

So, why do I care? Just grab my Leaf and be happy, right? Well, a funny thing happened when I took the log I've been keeping and estimated how both a Volt and a Leaf would have done. It turned out I would have used more gas driving the Leaf. My driving pattern may be atypical, but most days I drive 30 miles or less. Occasionally I drive 150-300 miles in a day. With the Leaf I would have to rent or borrow a car for those longer trips. Even if I used a (stock) Prius on those days, the Volt would get a 30 to 40 mile head start on fuel use, and even if GM is lying about the Volt getting 50 MPG in charge sustaining mode, the Prius would use more gas.

So, perhaps you can forgive me for my reaction a week ago, and for spouting the heresy that a Volt may be closer to an EV than it is to an HEV.
 
We need to be fair to GM's marketing campaign for the moment.. Think about it from the layman's viewpoint. They've had it shoved down their throat for the last 10 years that hybrids "never have to be plugged in." GM wants people to know that this is something different. And though I still think it is a hybrid of sorts, I agree it probably needs a different name for marketing purposes. Years from now when these cars are more common, the consumer will be more educated.
 
So, do we need different classes for the Parallel and the Serial plug-in Hybrids?

Or, just plug-in and not?

To me, "external" electrical charging to get energy is just using e-fuel.

A "real" hybrid would g-fuel and e-fuel.

A "hybrid" that does not e-fuel ... is really just a more complex ICE, cleverly done with some temporary energy storage (like a battery or wind-up spring) to get better mileage. Perhaps better called an "EMOB" (Extended Mileage Oil Burner) or some such?
 
planet4ever said:
Curiously you listed three of the four classifications used by the Department of Energy, and failed to list the fourth:

Extended Range EVs (EREVs)
• Operates in series mode: ICE charges the battery and the battery powers the electric motor(s)
• Normally will operate in all-electric mode until battery is discharged, then ICE turns on to charge the battery.


In the case of Volt this is not strictly correct. The generator can propel the motor directly without going through the battery.

Anyway, I do consider both Volt EREVs and Hydrogen fuel cell cars as EVs. Leaf is a BEV.
 
garygid said:
So, do we need different classes for the Parallel and the Serial plug-in Hybrids?

Or, just plug-in and not?

To me, "external" electrical charging to get energy is just using e-fuel.

A "real" hybrid would g-fuel and e-fuel.

A "hybrid" that does not e-fuel ... is really just a more complex ICE, cleverly done with some temporary energy storage (like a battery or wind-up spring) to get better mileage. Perhaps better called an "EMOB" (Extended Mileage Oil Burner) or some such?
I tend to agree with most of what you said. Unfortunately this "hybrid" argument is one we needed to settle ten or more years ago. We're now stuck with confusing terminology.

I don't think serial vs. parallel is a useful distinction. So far as I know, Toyota doesn't have any plans like this, but if they were to keep the Prius engine and "synergy drive" while expanding to a 10 kWh battery and a traction motor as big as the Volt has, they might have a pretty decent EREV. It would be a parallel EREV, but the efficiency of a mechanical ICE-to-wheel connection might make up for the inefficiency of loading the ICE at a wider range of speeds.

As an end user, I don't care whether power gets transmitted from ICE to wheels via gears, or belts, or electrons, or hydraulic transmissions, or one fan blowing another! What matters to me is that I can travel a reasonable distance each day, at a reasonable freeway speed, including hills, without having to buy gasoline.

Of course everyone has different definitions of "reasonable", but based on my personal requirements, a Leaf does that. A Volt does that. No "hybrid" does, not even any PHEV I've heard of.
 
planet4ever said:
Curiously you listed three of the four classifications used by the Department of Energy, and failed to list the fourth:

Guilty as charged. I don't feel badly about that, however, as I strongly believe that the 'new' category - which I've only seen in that doc - is part of GM's marketing push rather than a legitimate technical classification. I might be wrong, though. I claim my prejudice. :oops: ;)

planet4ever said:
So, perhaps you can forgive me for my reaction a week ago, and for spouting the heresy that a Volt may be closer to an EV than it is to an HEV.

No need! I certainly appreciate the exchange because I learned a couple more things. Thank you!

Andy
 
As I said before, I don't consider serial vs. parallel to be significant. Put succinctly, I see a PHEV as an electric car in the city, hybrid on the freeway or when the battery is exhausted, while an EREV is electric everywhere, with an onboard ICE to take over if you run your battery down.

Acid test: Freeway with two lanes each direction. I'm in the right lane, with lots of juice in the battery, behind a truck going 60 up a slight incline. Left lane is a continual stream of traffic going 70. I see a gap coming up and floor it to merge into the left lane.

Is the ICE already on? ... Yes = HEV or PHEV
Does the ICE come on? ... Yes = PHEV. No = EREV.
 
planet4ever said:
Is the ICE already on? ... Yes = HEV or PHEV
Does the ICE come on? ... Yes = PHEV. No = EREV.

Thats sounds very subjective, if not arbitrary.

Just PHEV - with series, parallel distinctions is more logical to me.
 
Well, I've probably beaten this to death, but what I'm trying to say is that with an EREV the ICE never comes on until the battery hits a predefined Depth of Discharge. With a PHEV it can come on at any time due to load. That doesn't sound subjective to me.
 
planet4ever said:
Well, I've probably beaten this to death, but what I'm trying to say is that with an EREV the ICE never comes on until the battery hits a predefined Depth of Discharge. With a PHEV it can come on at any time due to load. That doesn't sound subjective to me.

PHEV = plug in hybrid EV. Where does it say anything about what you are writing ?

EREV is a marketing term GM coined and got doe to incorporate.
 
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