How did GM arrive at 230 mpg for the 2011 Chevrolet Volt? (The answer)

http://www.autoblog.com/2009/08/11/chevy-volt-gets-230-mpg-but-how/

To those who say "GM is lying" or "misstating the facts" the 230mpg rating is based on draft conversion by the EPA. If you think it is wrong metric then complain to the EPA. I mean if the EPA raised the estimate of the Prius next month to 62mpg does anyone think Toyota wouldn't take the ball and run with it?

The good news is also that running 100% of gasoline it still gets 50mpg due to the small fixed rpm high efficiency generator instead of using a variable rpm engine. The generator provides constant power to the battery pack (like a faucet filling a sink) and the high power electic motor can use what it needs when it needs (lot durring acceleration, and little durring coasting) like scooping water out of the sink in a bucket.

With electricity being about 1/3 (@ $4 a gallon gas) to 1/4th (@ $5 a gallon gas) compared to the per mile cost of gasoline the greater % of driving on electric the cheaper your fuel costs.

That is at $0.11 kwh retail pricing. If utilities offer off peak pricing to residences (currently about $0.04) for charging EV then cost per mile could be 8x to 10x cheaper than gas.

Imagine cutting your "fuel bill" by 75% to 90% without reducing miles traveled or being limited in range.

However, 50 mpg is itself impressive. They should go with that figure, and state that those who are able to plug in their vehicles can get additional mileage from that charge.

Maybe the final version will require both numbers on the dealer sticker.

I'm sure the EPA has a contact form or something available. Maybe I'll suggest this to them.

And 50 mpg is nothing. They have cars that blow this away in europe.

train/bus.

I could see the justification for a train if it is a fairly direct route. But a bicycle is a ridiculous idea.

"Up to 40 miles"
You can't commute 20 miles each way and expect to really make it on the battery.

engineers generally quote the median system performance. So some people will find they never get the full 40 miles out of the bettery before the gas engine kicks in, and a similar number will manage to go 45 or even 50 miles. I, too, think little of your <40 miles = train/transit argument; even though I don't own a car and have preferred transit for many years, it's not always the optimal choice.

lies gang territory, and I work 4pm to Midnight. and the busses stop running at 11.

at this point in time it isn't feasible to have either aroung here. That car can go 230 miles on the equivalent of one gallon of gas in cost of electricity as long as you stay within it's rated electric only powered drive. Here that would be an even bigger number cause we only pay 8.9 cents a kwh. It blows me away that most can't seem to understand whats being said when they say it gets 230 mpg in city mode.

we live in one.

When will they just stop lying and deceiving consumers?

They tried to feed us the B.S. that ethanol would cut pollution and make us energy independent

The only thing it is doing is increasing you fuel bill, and making Archer Daniel Midline wealthy

Currently the average passenger car gets 31 mpg and the average light truck (or SUV) gets 23 mpg.

We have focused most of our efforts into improving the mpg rating of passenger cars, yet the biggest potential lies in improving the average light truck rating.

For instance, let's say we were able to improve the average passenger car's rating to 36 mpg, for an improvement of 5mpg. For a car that drives 10,000 miles per year, you will save about 45 gals per year. Now consider if you improved the average light truck rating from 23mpg to 28mpg. For those same 10,000 miles, you will have saved almost 78 gals per year.

Smaller engine. Diesel engine.
Tough to do in this country when so many people have penis envy and can't stand having a smaller engine but I'd be first in line to buy one.

http://adage.com/article?article_id=138244

Looks nice, but GM's quality being nowhere near it once purportedly was and all...

Most places seem to indicate $40K and with a $7.5K tax credit it should be around $32K after credit.

The battery pack is extremely expensive. Using Telsa battery pack as a comparison and scaling down to lower capacity my guestimate it the battery pack is about $8K to $10K.

If GM can achieve a 50% reduction in battery costs from economies of scale that could achieve $5K in cost savings right there.

I think GM "could" have it down to $35K or $27K w/ rebate within a few years.

Seeing as how they're measure 0 subsets of the range I gave.

Your average car only needs about 40 horsepower to maintain highway speeds on flat surfaces, so that leaves plenty of power to pump back into the batteries, and to run a heater, A/C compressor, lights, radio, power steering, power brakes, etc.


I had a similar idea a few years ago:

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=102&topic_id=2336543&mesg_id=2337457

My idea had a bigger battery and smaller engine.

not by driving like a turtle but by exercising some simple, common sense efficient driving techniques. it's not unusual to achieve this kind of mileage in a Prius. though of course if you're one of those teeny boppers who likes to accelerate like a jackrabbit at every light, only to slam on the brakes at the last second at the next stoplight, you would be lucky to get half that. a lot of it has to do with your personal driving habits.

I don't have a hybrid, but proper driving techniques can save a lot of fuel in just about any vehicle.

but really, 230 MPG is as good a number as any when you're looking at a plug-in. It's not a corporate lie, it's that the fuel economy numbers are meaningless for that kind of vehicle except for long-distance driving.

A drug manufactuer came out with a warning label for a drug
that said Only 1% of the people that use the drug_{for uses indicated on the label} experienced serious side effects, all the while knowing that 90% of the people using the drug are using the drug for reasons other than the label, then that's deceptive. It's why we have an FDA to regulate claims.
And it's why we need an EPA to regulate outlandish claims about fuel economy with these plug in cars because in reality, people are going to be using the gas engine part of the equation a lot more than the GM formula takes into account.

of such a system. The gasoline engine runs at its lowest specific fuel consumption in an on/off or load/unload mode. The car is less dependent on the driver for fuel economy. Still, fast accelerations from stops will cut into fuel economy. But even here, by limiting amperage this can be controlled. Ideally the engine would be sized to produce maximum power continuously at highway speeds and expected passenger load.

Then there are incremental improvements such as low friction parts, high coolant temperatures, exhaust gas heat utilization, combustion control etc. By making engine replacement every few years a maintenance function, newer updated engines could be installed. Something we don't really do now.

including the regular gasoline mpg ratings. But it doesn't really matter as long as some standard is decided upon and all plug-in hybrids are tested in the same way. It may be impossible to make a fair and meaningful comparison between a plug-in hybrid and a regular hybrid but that shouldn't matter much either because I think all hybrids will become plugins in the near future.

Millions of people can't park near an electrical outlet. Why should they pay for the extra plugin hardware that they can't use? It should be an option rather than standard equipment.

how much does one's home electricity bill go up by, assuming they have a readily available AC outlet outside? :D

$40,000 too. It's a parlor trick. A pricey one. And as for GM's various antics of the last few years, I wouldn't trust them as far as I could throw them.

Battery pack is 8.8KWH effective and good for 40 miles.
That works out to 0.22 KWH per mile and in line with other EV.

Nationwide electrical average is $0.11 per KWH which works out to 2.5 cent per mile.

Lets look at comparable gasoline costs.

At $4 per gallon gas.
25mpg = 0.16 per mile (6x as much)
32mpg = 0.12 per mile (5x as much)
50mpg = 0.08 per mile (3x as much)

Over the 10 year life of a vehicle I think average gasoline cost likely will be at least $5 per gallon.

At $5 per gallon gas.
25mpg = 0.20 per mile (8x as much)
32mpg = 0.15 per mile (6x as much)
50mpg = 0.10 per mile (4x as much)

At $6 per gallon gas.
25mpg = 0.24 per mile (10x as much)
32mpg = 0.18 per mile (7x as much)
50mpg = 0.12 per mile (5x as much)

Lastly that is at full retail electrical rate ($0.11) CA has started mandating off peak charging of EV be charged commercial off peak rate ($0.04 per KWH). That brings cost of an EV down from 2.5 center per mile to 1.0 center per mile.

At $6 gasoline and off peak charging rates ($0.04 KWH) electrical vehicle would reduce gasoline bill by $12 for every $1 it increases your electric bill.

12,000 miles @ $6 gas & 50 mpg = $1440
12,000 miles @ 0.04 KWH = $105

I would gladly trade my electric bill going up $105 to get rid of a $1440 gasoline bill.
Even if you used the Volt only half electric $50 increase to get rid of $700 in gasoline.

Electricity is a magnitude more efficient than gasoline.

if I lived in an Escher drawing and commuted to and from work - downhill each way.

that millions of people have no way to park their car near an outlet at night. Plugin hybrids and plugin all-electric are great for people who can actually plug in, but it's not a one size fits all solution, at least not without huge infrastructure investment. Other solutions also need to be found.

assumming a relatively conservative 75%/25% electric/gasoline split and 12,000 miles per year.

If someday only 20% of vehicles are EV or plug in extended range vehicles it could cut oil imports by 30% or more.

It doesn't need to be 100% of the population to have a large effect simply because the gross reduction is so much.

and we need to do it in a way that's available to everyone.

How about EV for most, expanded mass transit, hydrogen fuel cell research for heavy vehicles (semis, construction, bus fleets etc) and plug in hybrids cutting gasoline usage by 87% for those that still use gasoline?

Basically the all the above plan.

Obviously a combination of solutions will be the ultimate answer.

However, your set of solutions leaves those who can't plug in with no alternative except mass transit. Whether or not you or I like it, that will not fly politically with the American people.

Is there any reason you only mention hydrogen cells for heavy vehicles? Why not for family cars?

charge the batt or just provide DC?

Believe it was from france. So I can't take credit for the idea but maybe since I am not a physicist, maybe you can explain why a windmill strapped to the roof wouldn't work.

Law of Consevation of Energy
http://en.wikipedia.org/wiki/Conservation_of_energy

A windmill doesn't make energy it simply transfers energy.

It transfers energy from the wind (thus slowing down the wind) to the gears (kinetic energy) which the generator converts (transfers) to electricity.

So in a static windmill the wind behind the windmills is slightly less than the wind in front of them. Now the size of windmill vs the amount of energy in wind is tiny so the reduction is a small but percentage but it always happens.

Energy can not be created nor destroyed it can only be converted or transferred.

How does this apply to a car?

Wind energy is actually wind resistance.

Assuming a perfect machine (machine with no "loss" of energy via friction, heat, other undesirable transfers, i.e. 100% efficient) if the windmill generates 100W it does so by increasing the wind resistance of the vehicle. The car's engine must now burn 100W more fuel to keep the same speed as the unmodified car.

Now no windmill (or no machine in general) is a "perfect machine" (they are theoretical only) so in reality it would be more like windmill "generated" (which we know really means transfers) 100W but car thus needs to burn 105W of fuel to compensate.

Essentially no free lunch in physics. It is only useful to transfer energy when it would be "lost" anyways. Now energy technically can't be lost/destroyed but it can be converted/transferred into a form we find undesirable. Generally the term "lost energy" refers to energy converted into an unusable form. When you hit the brakes your car's speed (kinetic energy) is converted into heat (waste energy) by your brakes by the friction of the brake pad. This is why the brake pads wear out, they are ablated in the process of converting kinetic energy into thermal energy. Since the heat (thermal energy) is not used it is wasted, this is a source of potential power. Regenerative braking captures some of that "wasted" heat and generates electricity from it.

All that wasted wind when the car isn't in motion!

It is unlikely a windmill would generate enough power when the car is stuck in traffic at ground level (very low kinetic energy) to overcome the inefficiencies created when vehicle is moving at high speed (high kinetic energy).

Plastics make it possible!