Volt's aerodynamic design means 80 cent charges
Latest picture of Chevy Volt's front endSeveral months ago, much to the surprise of GM engineers, it was realized that reducing aerodynamic drag, rather than shedding some pounds, was going to be the key to the Chevy Volt's ability to achieve 40 miles of pure electricity. After months of wind tests and modeling, the Volt's design is almost complete and GM is showing off some design elements on the GMNext site.
Anyway, GM is hosting an open chat with GM's chief Volt designer, Bob Boniface on August 19 at 3:00 PM. Click here to register.
Also, check out this Volt video covering issues like charging costs and more. GM figures it will cost $.80 cents per day for 40 miles of electricity.
posted by Dahcredyns at
2:38 PM
19 Comments:
I just love when you add some technical juice :-) This is very interesting that it is aerodynamics, not weight, that affects fuel efficiency most of all.
$.80 cents per day for 40 miles of electricity.
Without A/C and heating, I suppose :-) And as I explained recently, in a very hot (or cold weather) climate control can cut the distance in half.
And probably without hitting the gas pedal too hard as well. No doubt that 40 miles of electricity are probably going to be pretty perfect world.
The aerodynamic/weight issue is very interesting. I met with a number of Volt engineers back in April and they had to run the numbers over and over because they just couldn't believe what the data was telling them.
Still, I think the data might produce a result that could anger some original Volt fans. When I was in the wind tunnel checking out a model - before I knew it was the latest Volt - I was very curious because the model had a very Prius-like shape in overall proportions. Not nearly as Prius-like as the pictures leaking out of the new Honda hybrid, but still much more like the Prius than the original Volt concept.
I'm sure GM designers and engineers fought this as much as possible - looking like the Prius - but I'm very curious to see the final design proportions.
And probably without hitting the gas pedal too hard as well.
Ohh, that is for sure. Nevertheless, it is relatively easy to drive smoothly. Saving on cooling and heating, though not impossible, is a harder task. This is especially important for the congested roads, where such cars are claimed to be the silver bullet.
Not that I am all against the idea, anyway such cars are MUCH MORE fuel efficient, just noting some imperfections.
You know what? It would be entirely different if GM had not just completed this little exercise. They built a vehicle from the ground up with the lowest coefficient of drag EVER and a range of 140 miles with NiMH batteries (the EV1). And now are led to believe that engineers are just now figuring out the importance of aerodynamics? Unconscionable.
ALl GM had to do was reuse their EV1 technology and the Volt would be so much further along.
All GM had to do was resurrect their series hybrid EV1 and viola', instant Volt.
http://en.wikipedia.org/wiki/Image:GMEV1serieshybrid.jpg
Don't get me wrong, I want the Volt ASAP but struggle to understand why I have to wait so long! GM acts as if the EV1 never existed or as if they did not own intellectual rights to the vehicle!
jabroni-
many times GM has claimed that the reason they will be successful with the Volt is exactly because of the EV1. likewise, they've admitted that dismantling the EV1 program was a mistake, though they would still be losing tons of money on the program today if they kept it up. gm has told me it takes about a million units (sales) to start achieving economies of scale on such a vehicle. the EV1 would have been a good bit more expensive than the prius and smaller, so it seems hard to believe that the EV1 would have come anywhere close to such a sales figure. of course, however, it would have them better positioned on EV technology today.
re: areodynamics - GM set out to make a very chevy looking PHEV, or range extended EV. they didn't want it to look like the EV1 or the Prius - like some science experiment - as GM has called such vehicles in the past. i think that's fair when your goal is to sell millions of these vehicles.
a significant percent of american consumers hate the way the prius looks.
obviously, gm knew that aerodynamics were going to be important with the volt. aerodynamics weren't disregarded. however, when testing started indicating that the Volt wasn't going to be able to achieve 40 miles of electricity, they started doing all kinds of testing, and trying to figure out where they could reduce weight. but they realized at this stage of the Volt's development, reducing drag would achieve more than reducing weight. since most of a vehicle's energy is used to move weight, this surprised many of gm's engineers.
moreover, the EV1 was a much smaller car. the Volt's goal is to achieve 4 - 5 passenger comfort. that cannot be achieved by just replicating the EV1's design and making it bigger.
yes, GM could have just ressurected the EV1, but the potential of the EV1 is nonexistent compared to the Volt, and GM has to think big to achieve cost-effectiveness - not just for consumers, but for profitability.
we're all dying to get our hands on a next gen car like the Volt, and there is no doubt that automakers have made many mistakes along the way that have stymied the industry that have us all frustrated.
I guess I was trying to figure out why it would take so long to replicate the electronics, motor, charging, climate control, etc. I agree that the next EV needs to have 4 doors and be more practical and it is too bad the final production Volt will not look like the original concept. I know a lot of folks at gm-volt.com are disappointed and think that the Volt is now going to look like every other sedan...
I think a lot of original fans of the Volt nation wanted an electric camaro.
I imagine I'm more in your camp. I just want comfortable, practical functionality. Unfortunately, a huge percent of the auto industry has nothing to do with practicality and functionality, as well as a huge percent of auto consumers.
That mentality really irritates me, but it is what it is and, today, that mentality drives the auto industry.
From an engineering stand-point, their conclusions absolutely do not make any sense.
Weight is the number one killer of fuel economy in the city.
What their conclusion tells me is that they do not plan to achieve 40 mile ranges in the city...but basically on a flat road, cruising at a constant speed where aerodynamics will play a role...about above 40 miles an hour.
What this also tells me is that GM has once again simply lied about what it wants to achieve. It has touted the Volt as being something it simply is not.
It also indicates that any goal they had about achieving this goal in city driving was probably abandoned very very early on and they simply stuck with the only saving grace they have...getting 40 miles out of their batteries on very flat, very constant conditions.
Sad.
i disagree, noz. gm engineers were fully ready to try to lop off weight whereever possible to achieve 40 mile of electricity, but at its current state of development, drag, not weight, was more of a factor. that's a scientific fact that gm engineers were not easily convinced.
so what if the volt only gets 30 miles of electric drive, or even 20. in some conditions, it will get even more than 40. like all hybrids, conditions and driving style play a role.
Dahc,
As I said...regardless of what GM engineers found, aerodynamics simply does not play a role in a car's drag or efficiency below 40 miles. It just doesn't.
Which indicates to me that GM simply could not OR never intended the Volt to achieve the performance goal in the city at low speeds in stop/go traffic.
I don't know how GM engineers came to their conclusions but as a mechanical engineer with an aerospace degree and experience in aerodynamics, to me it doesn't make sense.
Frankly, I think their engineers being quoted as being stumped is just distraction.
they showed us a bunch of charts and math, some of which i have written down somewhere demonstrating this effect. for each measure of drag reduction versus a comparable weight reduction, drag had more impact on fuel economy. but that's at this stage of the Volt's development, not from a fresh start - at its current weight and current drag.
still, you might be right that this is based on highway type fuel economy, or steady speeds at least, which would mean far less electricity and fuel economy in the city. nonetheless, if you drive less than 40 miles, you'd still be achieving well over 100 mpg.
is that really so bad?
No not at all! I still think it's a definite step forward.
My point is I want a company I'm buying a product from to be upfront and honest and not switch the rules half way down the progress bar.
You my view on GM. For me, personally, they have lost ALL credibility. And it has nothing to do with the Volt.
I think GM's true colors were demonstrated very clearly when they are currenly crying a river regarding sales here of the environmentally disastrous SUVs...yet at the VERY SAME TIME, they are selling these same piles to China behind us.
What does that does tell you about their genuine responsibility about making a difference environmentally?
Nozferatu,
all big businesses are the same. 80 cent per 40 miles, in comparison to 4 dollars for Toyota Camry Hybrid or 6-8 dollars for most mid-size sedans is pretty cool. I also do not understand how aerodynamics could not affect efficiency at smaller speeds (in that 40 mph is pretty good a speed). Of course, it does unless you are driving in a vacuum.
I also do not understand how aerodynamics could not affect efficiency at smaller speeds (in that 40 mph is pretty good a speed). Of course, it does unless you are driving in a vacuum.
Because it doesn't. It's a simple as that. Plain old aerodynamics. At low speeds, aerodynamics does not play enough of a role to make such a difference.
AGAIN...I simply believe that GM is assuming constant speed at constant conditions. Under such circumstances, weight makes very very very little difference because now you are not dealing with changes in momentum....but are simply trying to maintain a certain speed.
I simply do not believe GM for saying the range of the Volt is affected more due to aerodynamics than weight....ESPECIALLY if they are talking about stop/go traffic. That is just plain BS on their part.
Let's be fair to GM and their engineers. Here is the mileage range claim from the GM Volt Website.
Q: What is the driving range of the Chevy Volt?
A: The car is being designed to drive at least 40 miles on pure electricity stored in the battery from overnight home charging. After that the gas engine will kick in and allow the car to be driven up to 400 miles on a full tank (6-7 gallons) of gas.
As you can see, it simply states "at least 40 miles", no mention of driving style, etc.
This is the right type of information from GM at this point in its development and for a general audience. Anything more technical at this point gives too much information to the competition. Many of the car makers provide even less information during their development processes for good reason, it is very competitive to say the least.
Let's wait and see what they develop before we are judgemental.
I do not work for GM. I currently own cars from GM,Mazda and Chrysler. I make purchase decision based on value offered by all manufacturers.
I am also an engineer and would state that aerodynamics does play a role is speeds below 40 mph, although it is less of a factor at lower speeds. Weight is likely the dominant factor in city driving but I would suggest that public transportation is likely the best solution for city driving regardless.
Interesting discussion and debate. One that would not have occured even 5 years ago.....
Nozferatu, your concerns about city range for the volt, momentum changes, etc. don't seem to take regenerative braking into account. The volt's ability to recapture braking energy may well excede that of the prius, and then mass becomes much less of a factor.
That may be true. I guess we'll have to see. But I'm in the camp of I'm not buying it.
I think the Volt will be an engineering success. It's costs that worry me. Can GM sell the Volt at a price that will appease both consumers and GM's board?
They'll probably have to sell at a loss initially as supply chains are developed, so how many Volts will GM have to sell before making any money? And, how long will it take them to achieve such production numbers?
aerodynamics is critical for fast cars. but city cars which runs at a maximum of 30-40 mph it is a negligible factor.
Hybrid cars is best to provide both the speed and fuel effeciency we are looking for.
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Green Cars
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