Chevy Volt - Electric Car

[nintenho]

stolen from another forum.

http://www.chevrolet.com/electriccar/

-A single charge gets you 40 miles of travel. Good for short commutes to work.

-After using the charge, the car uses gasoline or E-85 to recharge the car generator. Through this, your gas mileage is roughly 150mpg on short trips(60 miles), or 50mpg on long trips(greater than 60 miles).

-The car has entered production, and will be available in 2010.

-While there's no word yet on what it might cost, GM has reportedly said that it's willing to lose money initially in order to get the car produced and sold. Experts expect it to debut anywhere from $20,000 to $40,000.

I never would have thought we'd have cars with that mileage by 2010. The biodeisel and E85 options are also very nice. I'd definitely consider a car like this (even though it probably has 0-60 mph in 10 seconds). I heard that the car body will be changed on the final version because the current one is just meant to look cool and not be aerodynamic at all.

edit: forgot to mention it's a plug-in hybrid.

 

[Simon F]

-After using the charge, the car uses gasoline or E-85 to recharge the car generator. Through this, your gas mileage is roughly 150mpg on short trips(60 miles), or 50mpg on long trips(greater than 60 miles).

How do they define what sort of driving is done in "short" and "long" trips here? A "short" trip, to me, implies urban, stop/start driving and a "long" trip would be a motor/freeway journey. These consumption figures seem to be back-the-front to what I would have expected.

 

[ninelven]

It is defined by the range of the vehicle on batteries alone. Since short trips will only use the batteries which can be recharged by plugging the car into an outlet, you get the 150mpg equivalent. Trips over 60 miles will activate the generator bringing the efficiency down.

 

[nintenho]

Yeah, normal EPA numbers probably don't apply to this since it's the only hybrid that can go such a long distance without gas (although the hybrid mode is insanely efficient). What I forgot to mention is that this car is a plug-in hybrid. Meaning that you can recharge it by plugging it into a wall socket so I assume you can go years without actually using a drop of gas as long as you don't drive long distances. I wonder how the transmission options are set up for this car. Does it let you decide when to go to electric mode (and thus limit performance?) like a normal hybrid or does it switch by itself when it needs to?

Engineering wise, there's probably not a lot different about this hybrid compared to others besides more/bigger batteries. I hope the performance numbers aren't too weird to figure out when comparing hybrid and electric modes.

 

[Sxotty]

How do they define what sort of driving is done in "short" and "long" trips here? A "short" trip, to me, implies urban, stop/start driving and a "long" trip would be a motor/freeway journey. These consumption figures seem to be back-the-front to what I would have expected.

You have it bass ackwards.

Start stop= good for a hybrid you recharge when you stop. Freeway = bad, only discharge.

I actually know quite a bit about this beast at the moment, but my question has always been about climate controls.

 

[nelg]

Here is a good source of info.........
http://www.gm-volt.com/

here is also a cooler Opel version, the Flextreme ........

http://car-reviews.automobile.com/Opel/concept/2007-opel-flextreme-concept/3185/

 

[Simon F]

You have it bass ackwards.

Start stop= good for a hybrid you recharge when you stop. Freeway = bad, only discharge.

In my opinion, stop-start implies lots of city driving with, e.g., traffic lights. Even allowing for regenerative braking, the amount of energy turned into heat due to deceleration is going to be significant. There is far less lost on motor/freeway journeys.

Of course, if by short journeys they only mean those that are strictly within the range of the battery, then I guess they will be able to quote high figures.

 

[Sxotty]

In my opinion, stop-start implies lots of city driving with, e.g., traffic lights. Even allowing for regenerative braking, the amount of energy turned into heat due to deceleration is going to be significant. There is far less lost on motor/freeway journeys.

Of course, if by short journeys they only mean those that are strictly within the range of the battery, then I guess they will be able to quote high figures.

At freeway speeds you lose a lot of power from aerodynamics. Starting and stopping does lose some as the regenerative braking is not 100% efficient, but the high speed losses for aerodynamic reasons are worse for fuel economy.

 

[Mariner]

Bear in mind that the Volt is a very different prospect to current hybrids such as the Prius. The ICE engine is there entirely to generate electricity to recharge the battery with no linkage between the ICE and the drivetrain. A much more sensible option than the current complex hybrid nonsense.

From the wiki page:

GM plans to keep the lithium-ion battery in a state-of-charge (SOC) range of between 30% and 80%, with the on-board generator starting to recharge the battery at the 30% level.

Even when running the ICE, fuel efficiency should be much better than a standard car (with a small generator ICE running at a constant speed instead of a revving ICE) and it ought to be pretty simple to change the type of engine as necessary if fuel cells etc. become feasible.

I just hope this type of sensible design is successful and becomes commonplace in the near future.

 

[Sxotty]

Not to be nit picky, but 30-80% is a gigantic range and the actual value is critically important.

 

[RussSchultz]

Not to be nit picky, but 30-80% is a gigantic range and the actual value is critically important.

Um, I think its saying that the generator will turn on at 30%, and off at 80%, which seems perfectly normal to me.

 

[soylent]

Assuming there are no major undisclosed drawbacks, aptera's prototype is much cooler. Popular mechanics did a little thing on it a while back:

http://www.popularmechanics.com/automotive/new_cars/4237853.html

 

[Sxotty]

Um, I think its saying that the generator will turn on at 30%, and off at 80%, which seems perfectly normal to me.

That implies to me the generator is over sized though. It would be more economical to have the generator hold the battery on average at say 40% and wait till you get home to plug it in to bring it the rest of the way up. Especially if they are going to have ultra-caps in there to smooth things out.

 

[Arwin]

I think the Prius keeps it with 40%-60%. That way, the battery lasts almost forever, but you can only do about 7km on batteries only, at about 50km/h.

However, the Prius also the stop-and-go slow city traffic as consuming less.

The Prius current biggest weakness is, apart from maybe smallish batteries, that it likes to warm up its fuel engine, so that if in winter you take it for short trips, it becomes less efficient. Though if you do multiple short trips a day, that disadvantage drops away quickly.

On the highway at 114km/h (my favorite speed over here) it does 5.0l on 100km. When I do trips through (hilly) countryside, it drops down to as little as 2.5l/100km even if it needs frequent stops.

The power consumption figures shown in the OP are a bit pointless, as they include a full charge of the high-capacity batteries to get those, which is why the drop is so big.

But one thing is certain, hybrids are coming and won't go away soon. The good thing about them is that they are compatible with almost any form of power.

The new Prius model supposedly comes in 2009 though, and supposedly is twice as efficient. Will be interesting. Good times for hybrid-minded / environmentally minded people, I think.

 

[RussSchultz]

That implies to me the generator is over sized though. It would be more economical to have the generator hold the battery on average at say 40% and wait till you get home to plug it in to bring it the rest of the way up. Especially if they are going to have ultra-caps in there to smooth things out.

That means you'll have the generator coming on for short durations, which is not efficient.

You want it to come on, run for a decent amount of time, then shut off for a decent amount of time.

 

[Sxotty]

That means you'll have the generator coming on for short durations, which is not efficient.

You want it to come on, run for a decent amount of time, then shut off for a decent amount of time.

I was thinking the opposite. Once you reach 40% the generator turns on and it is sized so that on average it will only sustain the charge, not add to the charge. As you accelerate you discharge the caps, decelerate you charge them. Generator provides the power for aerodynamic drag.

Think of it like the electricity grid. You have regulation, scheduled and load following. The regulation is from caps, and load following is from the battery and the scheduled is from the generator once you reach the SOC they decide is the best. It is interesting though they seem to be picking 30% for the low end. It brings into question certain other claims by the manufacturers, but it might simply be deciding to error on the side of caution.

 

[nintenho]

The power consumption figures shown in the OP are a bit pointless, as they include a full charge of the high-capacity batteries to get those, which is why the drop is so big.

The new Prius model supposedly comes in 2009 though, and supposedly is twice as efficient. Will be interesting. Good times for hybrid-minded / environmentally minded people, I think.

the way they estimate mileage makes sense since this is probably marketed at people who expect to do most of their driving using electric grid power.

interesting thing about the next Prius:
http://en.wikipedia.org/wiki/Plug-in_hybrid

On July 25, 2007, Japan's Ministry of Land, Infrastructure and Transport certified Toyota's plug-in hybrid for use on public roads, making it the first automobile to attain such approval. Toyota plans to conduct road tests to verify its all-electric range. The plug-in Prius has an all-electric range of 13 km (8 mi).[23]

It seems it will also be a plug-in hybrid but it's not able to drive as far as the Volt without using gas. it's possible that those are for a prototype that doesn't have the full size batteries though.

 

[_xxx_]

That mileage is really just wishful thinking. I'd reckon with maybe half that in real life.

 

[nintenho]

That mileage is really just wishful thinking. I'd reckon with maybe half that in real life.

why would you guess that? do you base that on the real-world mileage versus the epa mileage for regular hybrids?

 

[Mintmaster]

In my opinion, stop-start implies lots of city driving with, e.g., traffic lights. Even allowing for regenerative braking, the amount of energy turned into heat due to deceleration is going to be significant. There is far less lost on motor/freeway journeys.

Even for today's hybrids (not plug-in), fuel efficiency is worse on the highway, and it pretty much matches an equally performing gas-only engine for obvious reasons.

Starting and stopping doesn't consume as much energy as you think, especially when hybrids can recover the majority of that energy (AFAIK, it's ~80%). Reaching 35MPH in a heavy two-ton car needs only a quarter megajoule of energy. A hybrid, then, could probably accelerate to this speed and stop 1000 times per gallon.

Air resistance, especially at high speeds, is a continuous load that the engine has to counter.