Posted on 10/11/2010 12:10:12 PM PDT by dangerdoc
Interesting news from General Motors today that's resulted in some puzzled expressions at Engadget HQ. We've learned that the Volt, which Chevrolet has been making quite a fuss about calling an "extended range electric vehicle," is actually just a traditional hybrid with some... potentially misleading marketing behind it. Since the concept stage the company has been saying how the onboard internal combustion engine was just to charge the batteries, that only the electric motors (there are two) are actually connected to the drivetrain. Indeed that's what we were told in person when we test drove the thing back in March. We're now learning that is not the case, that the Volt's gasoline engine can directly provide power to the wheels in concert with the electric motors.
Is that a problem? In terms of efficiency the answer is "apparently not," as we're guessing the car would not have been designed this way if it weren't the most frugal way to go. So, why all the deception? Why insist this isn't just a hybrid when it apparently is? When the company went looking for a government bailout it was in part awarded one because of the innovation shown in the Volt. Now that we're learning the Volt is basically just a plug-in hybrid with a bigger than average battery pack (Popular Mechanics is finding 30-odd miles of purely electric range), we're left wondering: where's the innovation?
Select Volt. Select Technology.
First Sentence:
The Volt propulsion system is powered exclusively by electricity.
GM was talking of the Volt being a “all electrically driven” and “revolutionary” blah, blah, blah.
I looked at all 17 frames but couldn't find your sentence.
Source for your quote "all electrically driven"?
Since I’m on a BlackBerry I’m using GM mobile site.
It must be different than what you see on a PC.
Under “New era in automotive transportation”
2nd Paragraph starts:
The Volt uses electricity to move the wheels at all times and speeds.
- - - - - -
The Chevrolet Volt is not a hybrid.
http://media.gm.com/media/us/en/vehicles/chevrolet/volt/2011.html
The Volt proves electric driving can be spirited. Not only does the Volt reach a top speed of 100 mph, the electric drive unit’s excellent low speed torque of 273 lb.-ft. (368 Nm) takes it from 0 to 60 mph in less than 9.0 seconds and the quarter mile in less than 17.0 seconds.
Their press release:
Applicable quote:
“The Chevrolet Volt is not a hybrid. It is a one-of-a-kind, all-electrically driven vehicle designed and engineered to operate in all climates.”
GM’s response as of yesterday is: “There is no direct mechanical connection (fixed gear ratio) between the Volt’s extended-range 1.4L engine and the drive wheels.”
Uh... in engineering, we don’t draw distinctions between fixed and variable gear ratios when we talk about “mechanical connection.” Does the force being applied to the drivetrain originate only in the electrical motor? Then it is an “all electrical drive.” Does any of the force being applied to the drivetrain originate in anything other than the electrical motor(s)? Well then, it isn’t “all electrically driven.”
That word “all” means that there is “nothing else.” And there, they’re not telling the truth.
“The Volt uses electricity to move the wheels at all times and speeds.”
True.
Under about 65 mph that is true.
Really? That is the position you want to take?
Did you help Bill Clinton prepare his press releases?
You didn't indicate where the statement is false. Please stay with the facts and refrain from personal attacks.
Who's talking about variable gear ratios?
Maybe you can fool yourself but you are not fooling anyone else.
In the +3 months you’ve been here I would have thought you would have learned something more than that.
Have a nice day.
Equivocation.
It is not an “all electrical drive.” Period.
GM is. They’re saying that there is no coupling of the engine to the drivetrain through “a fixed gear ratio.” There is a coupling of the engine to the drivetrain through the planetary, and the opposite of a fixed gear ratio is a variable gear ratio.
After the Clinton administration, I became very adept at parsing PR written by lawyers. And that’s what this is: PR written by lawyers.
If the vehicle were “all electric drive” the engine would have no way of transmitting power to the drivetrain through any geartrain.
The engine would have an alternator (or generator) fixed-coupled to the crankshaft and the alternator would charge the batteries, which would then drive the electric motors which are coupled to the drivetrain. That would be an “all electric drive” vehicle, just as diesel-electric locomotives have no mechanical coupling of the diesels to the wheels. That’s an example of all-electric drive.
Please explain to me how the engine is mechanically coupled to the planetary gears. Thank you.
In my three months I have learned that the first reaction when one cannot refute a post is to personally attack the poster (as you did to me with your Clinton remark) and the second reaction is to claim the poster is ignorant since he has been here less time than the attacker (as you just did).
At any speed, there is energy lost in the energy conversion from mechanical-to-electrical power and then back to mechanical.
In engineering, we have this thing called “the Second Law of Thermodynamics” which stated in layman’s terms says “You can’t break even.”
The three laws of Thermo are (in layman’s terms):
1. You can’t win.
2. You can’t break even.
3. You can’t quit the game.
(and people wonder why we engineers get so weary when we hear of the next brilliant energy saving scheme...)
1 means that you can’t make an energy process wherein you get more energy out than you put in. No free lunches, period.
2 means that there’s a loss every time you convert energy from one form to another. The losses escape from the system typically by heat.
3 means that you can’t set up a different set of ground rules somewhere else in the universe, that your perpetual motion machine would work if you could just get off this whole nasty planet, etc. The universe works the same way things work here. Death, taxes and thermo. They all suck.
The engineers at Chevy probably discovered that with all-electric drive that their MPG at highway speeds was not what they needed and also that their range started to suffer quickly. So they decided to divert some power from the engine to the drivetrain directly to hit their MPG numbers.
I don’t begrudge the GM engineers their solution, only that GM execs and their PR machine lied to the public. It isn’t “all electric drive” and it isn’t a “series drive.” It is a selectively parallel drive, much like existing hybrids. There’s no shame in that unless they were making other claims - which they were.
And I wouldn’t buy one either. There’s far better economy to be had in buying a diesel Audi sedan than buying a Volt.
Which is the case with the Volt in normal mode.
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