Topic: Volt = first 100mpg car

[drederick]

GM Claims 100 Miles-a-Gallon Volt `Bragging Rights' (Update2)

By Jeff Green

 Sept. 26 (Bloomberg) -- General Motors Corp. said it reached a preliminary agreement that clears the way for U.S. regulators to certify the Chevrolet Volt, an electric vehicle that can be recharged at home or with a 1.4-liter gasoline engine, as the first 100 mile-per-gallon car.

The country's biggest automaker, whose sales of pickup trucks and sport-utility vehicles collapsed this year as gasoline topped $4 a gallon, is cutting the mileage deal while urging Congress to approve $25 billion in government loans to help the industry meet new federal fuel-economy standards.

Earning a 100 mpg certification would give Detroit-based GM the holy grail auto companies began seeking following the oil shocks of the 1970s. The Environmental Protection Agency agreed to a testing method that will produce a rating at least that high, said Tony Posawatz, 48, vehicle-line director for the Volt in Warren, Michigan. The four-passenger car, which goes on sale in November 2010, will be able to travel 40 miles (64 kilometers) before the internal-combustion engine needs to recharge the battery.

http://www.bloomberg.com/apps/news?pid=20601103&sid=a2GgcMQbsIcU&refer=us

[Jameel]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

[Leviathan]

The gas engine + generator won't "fill" the batteries - that is what the plug is for. They will provide enough power to keep the car moving as usual though.

[drederick]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

The engine will be used to maintain the batteries charge once it is depleted to approx 30% - it is not going to charge them back up.

The main purpose of the engine will be to directly power the electric motors powering the wheels after the battery runs down.

[sirAQUAMAN64]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

The engine will be used to maintain the batteries charge once it is depleted to approx 30% - it is not going to charge them back up.

The main purpose of the engine will be to directly power the electric motors powering the wheels after the battery runs down.

I wonder how many people (like me perhaps) who would just keep putting gas in the car and rarely plug it in?

[drederick]

I wonder how many people (like me perhaps) who would just keep putting gas in the car and rarely plug it in?

Do you ever park any of your vehicles at your house where it was intended to be charged up from? if not, then maybe this vehicle isn't designed for you. I would be that most people would be able to take full advantage of the overnight charge.

So a statement like:
I wonder how many people (like me perhaps) who would just keep plugging it in overnight and rarely put gas in it?

is probably more applicable for this vehicle.

[echo7]

did GM already mentioned how much are the batteries if it needed to be replaced? For sure after a year or so it will not hold a full charge like any other battery operated product. OR is the car disposable?

[Jameel]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

The engine will be used to maintain the batteries charge once it is depleted to approx 30% - it is not going to charge them back up.

The main purpose of the engine will be to directly power the electric motors powering the wheels after the battery runs down.

Okay well even doing that, running the gasoline engine to power the electric motors to run the car.  Just seems odd.

[echo7]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

The engine will be used to maintain the batteries charge once it is depleted to approx 30% - it is not going to charge them back up.

The main purpose of the engine will be to directly power the electric motors powering the wheels after the battery runs down.

Okay well even doing that, running the gasoline engine to power the electric motors to run the car.  Just seems odd.

TRUE.... however if 1 Gal of gasoline would fully charge the batteries at 100%.. then I guess it make sense..

[vdk]

i don't see how gas engine - battery - electric motor - power car is more efficient/green than a straight gas engine - power car setup...

say a gas engine has an efficiency of ~30% (i won't bother to look that up)
and all it's power is used to charge the battery (now that's not 100% efficient either)
and then the battery will power the electric motor (not 100% efficient)

so why bother again? maybe i'm missing something...

[The Mighty Duck]

^ By using the gas engine to produce electricity, which then drives the electric motors, the gas engine can remain in its "sweet spot" - that is, the most efficient rpm for that engine.  With a conventional gas engine, the engine rpm depends on speed.  With the Volt, it should be able to stick to one rpm and simply produce power, and that's more efficient.

I wonder how many people (like me perhaps) who would just keep putting gas in the car and rarely plug it in?

I highly doubt anyone buying the Volt will not plug it in...  you don't buy a hybrid and then drive it like a Corvette, so why on earth would a Volt driver be so stupid as to not plug it in. 

[mmret]

^ By using the gas engine to produce electricity, which then drives the electric motors, the gas engine can remain in its "sweet spot" - that is, the most efficient rpm for that engine.  With a conventional gas engine, the engine rpm depends on speed.  With the Volt, it should be able to stick to one rpm and simply produce power, and that's more efficient.

We can already do that with a CVT.

The trouble with this of course is that when the amount of power required exceeds the efficient output level of the engine (probably not very hard to do) and the batteries (ie: the buffer) are dry, you're running entirely on gas and its probably a lot less efficient given that there are more stages of conversion to go through, plus weight of batteries, etc.

But yes always running the engine at 2000rpm assuming your buffer is large enough would be nice...you can always shut it down if the buffer is full and while idling at the lights you regenerate. Wonder what the loss % is though.

[LeftLand]

I'm not saying it's a totally bad idea, but does anybody else find it odd that they're going to use a gasoline engine to refill the batteries instead of driving the car.  I don't, seems weird to me!

I think a major reason is that they would have to give the car a mechanical drivetrain to do that, significantly adding to cost, weight, and complexity.  Even if direct mechanical drive is more efficient than the engine powering the batteries, it’s probably not worth it, especially given that the use of the engine is only meant to be an occasional backup when the driver gets “caught short” driving too far.  People who are going to do that regularly are probably not golng to buy Volts anyway.

[Triple Bob]

Charging the Volt about once daily will consume less electricity annually than the average home's refrigerator and freezer, the company said.

Now that's the important bit... v impressive car I think, congrats GM!

[G35X]

“ By using the gas engine to produce electricity, which then drives the electric motors, the gas engine can remain in its "sweet spot" - that is, the most efficient rpm for that engine… “  - Demosthenes

Then, why do we not see more automobiles with this propulsion arrangement with much smaller (lighter and cheaper) battery pack? Transmission (if any) and differential can be much simpler, too.  Diesel locomotives have this driving system, by the way. 

Just to be able to go 40 miles on batteries alone the Volt will be carrying a big, very expensive 16KWH battery pack.  When the state of charge of batteries goes down to 30% its ICE comes on supplying electric power to the driving motor and to the battery pack, making the Volt a rather anaemic (53HP) heavy automobile.  Suppose you start out your 200-mile trip with fully charged batteries, after the first 30 minutes or so you will be driving on the ICE power for almost three hours.  I think GM should let us know of the fuel consumption rate in this condition.   The Volt is a nice short-range commuter car, but certainly not a replacement for ordinary automobiles.  Its ICE is for just in case.  If your commuting distance is less than 40 miles, it is a great energy saver inasmuch as it utilizes otherwise wasted off-peak electricity.

[Leviathan]

I think GM should let us know of the fuel consumption rate in this condition.

They did and this guy's FAQ has your answer
Q: How many miles per gallon will the Chevy Volt get?
A: A bit of a trick question. For the first 40 miles it will get infinite mpg, because no gas will be burned. When the generator starts, the car will get an equivalent of 50 mpg thereafter. One can calculate the average mpg per for any length drive starting with a full battery: Total MPG = 50xM/(M-40)

The Volt is a nice short-range commuter car, but certainly not a replacement for ordinary automobiles.

Ah, but it is a replacement. Apparently the car will run just as well with the gas generator providing electrons as it does with the battery providing electrons.

making the Volt a rather anaemic (53HP) heavy automobile.

From GM's official press release here
"The Volt's electric drive unit delivers the equivalent of 150 horsepower, 273 lb-ft. (370 Nm) of instant torque"

[Zombie]

The gas generator just extends the range of the car. For most people the 40 miles per charge is enough for there daily commute. Making it a mostly electric car but on the off day that you need to go out of town or whatever you will be able too with the generator.

[tpl]

I think GM should let us know of the fuel consumption rate in this condition.

They did and this guy's FAQ has your answer
Q: How many miles per gallon will the Chevy Volt get?
A: A bit of a trick question. For the first 40 miles it will get infinite mpg, because no gas will be burned. When the generator starts, the car will get an equivalent of 50 mpg thereafter. One can calculate the average mpg per for any length drive starting with a full battery: Total MPG = 50xM/(M-40)

The Volt is a nice short-range commuter car, but certainly not a replacement for ordinary automobiles.

Ah, but it is a replacement. Apparently the car will run just as well with the gas generator providing electrons as it does with the battery providing electrons.

making the Volt a rather anaemic (53HP) heavy automobile.

From GM's official press release here
"The Volt's electric drive unit delivers the equivalent of 150 horsepower, 273 lb-ft. (370 Nm) of instant torque"[/color]

BUT.  If the gas engine can spin the generator against a 150 horsepower "load" of the electric motor then it must be capable of producing 150 bhp which is definitely isn't.  That 150 bhp has to come from somewhere.

So If by some magic the battery is flat you wont be going anywhere until the gas engine has rattled away for some time to get some charge into the battery.

So the car will not run properly unless they battery is 30% charged or thereabouts which to me would make it a bit problematical for driving across the rockies with a full load.

The next question that come to mind is: Can the car self start by which I mean, if the battery is completely flat is there are way with no external power source except maybe a tow trucks battery, of getting going again. Can the gas engine be started from a regular 12V source? Can the gas engine charge the main battery from dead flat.?

If not then I don't want one.

[The Mighty Duck]

Then, why do we not see more automobiles with this propulsion arrangement with much smaller (lighter and cheaper) battery pack? Transmission (if any) and differential can be much simpler, too.  Diesel locomotives have this driving system, by the way.

Because until fairly recently, gas was dirt cheap and nobody cared about fuel mileage.  It's only been in the last few years that gas has gone up so much in price and people have been demanding more efficient vehicles, and it takes time to bring a whole new vehicle with new technology to market.

Suppose you start out your 200-mile trip with fully charged batteries, after the first 30 minutes or so you will be driving on the ICE power for almost three hours.  I think GM should let us know of the fuel consumption rate in this condition.   The Volt is a nice short-range commuter car, but certainly not a replacement for ordinary automobiles.  Its ICE is for just in case.  If your commuting distance is less than 40 miles, it is a great energy saver inasmuch as it utilizes otherwise wasted off-peak electricity.

Why do people keep bringing this up?  No, the Volt is not for everyone.  If you commute more than 40 miles per day, you should probably look elsewhere.  But no one car is perfect for everyone, and the the Volt is no exception.  Like the Smart car, the Volt will be great around town but not as strong as a commuter (although likely better than the Smart!).  As others have said, a smart family might have a Volt and a traditional gas car for roadtrips...  nothing wrong with that.

[Leviathan]

BUT.  If the gas engine can spin the generator against a 150 horsepower "load" of the electric motor then it must be capable of producing 150 bhp which is definitely isn't.  That 150 bhp has to come from somewhere.

Do you drive your Fit using 100% throttle 100% of the time? Of course not, and you won't drive the Volt that way either so you don't need 150hp all the time. Apparently GM will tune the gas generator to several fixed RPMs and will choose according to the load requirement.

So If by some magic the battery is flat you wont be going anywhere until the gas engine has rattled away for some time to get some charge into the battery.

Apparently the Volt runs directly off the generator with any excess power generated going to the battery.

So the car will not run properly unless they battery is 30% charged or thereabouts which to me would make it a bit problematical for driving across the rockies with a full load.

30% charge is a soft "limit" and still represents 24miles of range. Your rockies trip will include up AND down grades and you'll get some of your energy back through regen braking.

The next question that come to mind is: Can the car self start by which I mean, if the battery is completely flat is there are way with no external power source except maybe a tow trucks battery, of getting going again. Can the gas engine be started from a regular 12V source? Can the gas engine charge the main battery from dead flat.?

If not then I don't want one.

Dunno that, we'll find out in 2 years I guess. Lutz joked on the Colbert Report that you could charge the Volt from the 110v outlet of a Hummer so there *IS* an option    But it doesn't sound like the Volt is for you anyway.