That's a lot of Explaining...

[PricklyPete]

So some people got to do some VOLT test driving...and the gas mileage after the battery depleted was a not so impressive 27mpg based off of the 50mpg that GM was touting. So GM fired back why...

http://www.autoblog.com/2010/08/26/why-the-sub-30-mpg-claim-for-chevrolet-volt-is-misleading-w-vid/

To be honest, I think GM has a point here and that 27mpg is not representative of what the EPA or real-life driving will result in. I'm still interested to see the figures. Isn't this thing supposed to be out any month now???

 

[ch33zw1z]

survey says: drive the car harder, use more fuel to go the same distance...

 

[LTC8K6]

It's plain easy math, though.

You are looking at pretty ordinary 4 cylinder mileage after the battery is depleted, based on the best guesses of range and fuel tank sizes.

The way you get big MPG numbers is to make shorter trips, where a large percentage of the miles is on the battery. Which is fine if those are going to be representative of how you will be driving the car.

Once you talk about longer trips, the mileage number looks less and less impressive.

One problem is that GM has not actually announced any hard numbers for anything. We aren't even sure of the fuel tank size.

 

[ch33zw1z]

I thought that in terms of Hybrids, long trips with moderate speed would yield the best mileage. Like doing 60 in a 65 for 100 miles. As opposed city driving, which is lots of stop go and uses more fuel.

 

[PricklyPete]

It's plain easy math, though.

You are looking at pretty ordinary 4 cylinder mileage after the battery is depleted, based on the best guesses of range and fuel tank sizes.

The way you get big MPG numbers is to make shorter trips, where a large percentage of the miles is on the battery. Which is fine if those are going to be representative of how you will be driving the car.

Once you talk about longer trips, the mileage number looks less and less impressive.

One problem is that GM has not actually announced any hard numbers for anything. We aren't even sure of the fuel tank size.

I agree with you. GM has to work hard to make sure they market this well. Reviewers are likely to report a lot of bad mileage numbers due to how they drive and will likely not focus on the positives.

 

[Demo24]

I thought that in terms of Hybrids, long trips with moderate speed would yield the best mileage. Like doing 60 in a 65 for 100 miles. As opposed city driving, which is lots of stop go and uses more fuel.

That's true of any vehicle, but Hybrids excel in the city because of the electric motors which can easily scoot you around town. However if there's no battery, then the advantage is no longer there.

 

[TraumaRN]

I thought that in terms of Hybrids, long trips with moderate speed would yield the best mileage. Like doing 60 in a 65 for 100 miles. As opposed city driving, which is lots of stop go and uses more fuel.

I can confirm that. Driving out to my in laws which is 80 miles of 55mph state highway and 10 miles of city driving usually will yield 52-55mpg easily even cracked 60mpg once when I had a strong tail wind

EDIT: But with my car and most hybrids you can get amazing city mileage witha light foot. I can easily average 60+mpg in pure city driving just buying groceries etc

 

[LTC8K6]

A commonly given range is 340 miles and a commonly given tank size is 9 gallons. Simple math gives us about 38mpg for a 340 mile trip. However, if we only went 80 miles, we might only use 3/4 gallon of fuel because 40 of those miles were on the battery. Now we have a 106mpg number.

Just an example, of course.

 

[CurseTheSky]

I was under the impression (and correct me if I'm wrong) that the Volt, unlike other hybrids was ALL battery until depleted, then all ICE. The Prius, on the other hand, runs on battery around town and automatically switches to the gasoline engine when it's most efficient (on the highway), which saves / charges the battery. Perhaps things have changed since I last read about the Volt, but if that still holds true, then you should be getting "infinite" mileage as long as you're only going the hundred (or several hundred) miles the battery will last for (and only paying for the kW/h to recharge at home).

 

[PricklyPete]

I was under the impression (and correct me if I'm wrong) that the Volt, unlike other hybrids was ALL battery until depleted, then all ICE. The Prius, on the other hand, runs on battery around town and automatically switches to the gasoline engine when it's most efficient (on the highway), which saves / charges the battery. Perhaps things have changed since I last read about the Volt, but if that still holds true, then you should be getting "infinite" mileage as long as you're only going the hundred (or several hundred) miles the battery will last for (and only paying for the kW/h to recharge at home).

Battery range is only supposed to be 40 miles on the Volt.

Battery is depleted and then ICE is used as a generator for the power needed to drive the car. The ICE doesn't produce enough power to recharge the batter and drive the car...but from reading the posted link, it looks like there are modes you can switch to (Mountain Mode in particular) where any extra electricity not needed to propel the car while in ICE mode will be used to charge the battery to a certain threshold to ensure you have enough power going up steep inclines. So it is not an on/off nature....but a finely tuned (we hope) algorithm that will take advantage of the power at hand as best it sees fit. One interesting side affect of all this computer control is I can see the versions of VOLT software increasing efficiency due to improved algorithms over time.

 

[CurseTheSky]

FOURTY MILES?!

...seriously?

If the thing can recharge at home in an hour or less, I could see it being useful for people that live close to work. If it takes a while to recharge and you've already driven to / from work and now need to go get some groceries, you're stuck with the ICE...

I would personally rather stick with a smaller traditional 4 cylinder at this point. I do appreciate what the Volt is doing in terms of innovation, however, and I hope that we'll be looking at a similar vehicle with a 100-200 mile battery-only range in the near future.

 

[exdeath]

You want to see real hybrids with real efficiency? All electric with a small gas turbine (scale model aircraft or cruise missile size) running constant rpm to charge the batteries.

 

[desy]

They base it on that 90% of peoples drivng is less than 40 miles, typical
They also want a 350 mile range vehicle to compete with normal cars.
The much smaller Imev goes 100-120 miles but drops, going up hills using heat and AC and so on and its a $30K vehicle.

 

[lurk3r]

It should be a nice system once they have a reasonable generator and charging system, and add a solar option. As is the generator is at best an afterthought.

Early adopters will suffer hard.

 

[speedy2]

I wonder if stacking other charging modes on top of it would be good? Solar? Regenerative Brakes, etc? Seems like a ok idea to yeild even better results.

 

[LTC8K6]

The battery is always there to help with the Volt for heavy acceleration or hill climbing. The tradeoff there is that the ICE then has to both move the car and bring the battery back up to it's depletion point, which uses more fuel.

The way you can quote a ridiculouly high mileage number is to take a trip of just over 40 miles.

Let's say the Volt's engine gets 40mpg in CS mode. Now let's take a 41 mile trip. We would theoretically use 1/40th of a gallon of gas to travel that 41 miles. I think that's 1,600mpg.

 

[LTC8K6]

I wonder if stacking other charging modes on top of it would be good? Solar? Regenerative Brakes, etc? Seems like a ok idea to yeild even better results.

It already has regen braking, and there will be a solar panel option later, but it will be more like the Prius solar panel option. There just isn't enough space for a meaningful solar panel installation regarding battery charging.

 

[desy]

It doesn't need solar or a better generator it needs better batteries
The end
Until they can have a lot less battery 'lighter vehicle' and higher density for longer range and quicker charging to elimiate one powertrain the electric vehicle is non relevant in a practical sense which is what a Volt is supposed to be, not a hybrid.

 

[speedy2]

The battery is always there to help with the Volt for heavy acceleration or hill climbing. The tradeoff there is that the ICE then has to both move the car and bring the battery back up to it's depletion point, which uses more fuel.

The way you can quote a ridiculouly high mileage number is to take a trip of just over 40 miles.

Let's say the Volt's engine gets 40mpg in CS mode. Now let's take a 41 mile trip. We would theoretically use 1/40th of a gallon of gas to travel that 41 miles. I think that's 1,600mpg.

This is where someone like me with a 6 mile one way trip to work everyday could save some big bucks on gas. But, to offset the payment I would need keep it forever.

 

[LTC8K6]

It doesn't need solar or a better generator it needs better batteries
The end
Until they can have a lot less battery 'lighter vehicle' and higher density for longer range and quicker charging to elimiate one powertrain the electric vehicle is non relevant in a practical sense which is what a Volt is supposed to be, not a hybrid.

It desperately needs a better engine too. GM is desperately trying to find one. :biggrin:

 

[speedy2]

You want to see real hybrids with real efficiency? All electric with a small gas turbine (scale model aircraft or cruise missile size) running constant rpm to charge the batteries.

That or a diesel.

 

[LTC8K6]

This is where someone like me with a 6 mile one way trip to work everyday could save some big bucks on gas. But, to offset the payment I would need keep it forever.

Yeah, you wouldn't put enough miles on it to break even. :biggrin:

But you fit the profile exactly and so do I.

I have an under 10 mile round trip daily. I could just drive the Volt back and forth to work until on one of the trips, the engine kicks in, and then I'd recharge when I got home or to work.

This way, most of my trips are on the battery, and I get that once in a while engine run to keep everything working properly.

A plug in Insight or Prius seems like it would kill the Volt, though. It's way cheaper to start, and it will get better overall mileage.

 

[desy]

Having the Best engine in the world won't bring the price down to sane commuter car prices. However, I agree they have to get the MPGS up
Only cheaper powerfull batteries and the elimination of one powertrain will drive the price to where I'd be interested

"Tony Posawatz, the Volt Line Director at GM, admits that they didn't initially spend a lot of resources on the extended-range feature of the first generation Volt, but says, "You can bet that we are already looking at advanced projects on what an extended-range feature should operate like in the belief that this propulsion system will resonate with customers. That may be a Stirling cycle engine, perhaps it’s a Wankel, a gas turbine, a small displacement motorcycle engine– you can extend the possibilities to a lot of different alternatives.”

 

[Mermaidman]

Predicting fuel mileage based on HALF a gallon of gasoline usage is asinine.

 

[PricklyPete]

Predicting fuel mileage based on HALF a gallon of gasoline usage is asinine.

agreed.