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GM Chevy Volt
- Thread starter vfx
- Start date
The Volt’s Gas Engine DOES Turn the Wheels. Sometimes.
Earlier reports pretty much on the mark. Previous GM staff either none the wiser or lying through their teeth.
Nothing against the car but it certainly isn't the "EV" they would like you to believe.
Earlier reports pretty much on the mark. Previous GM staff either none the wiser or lying through their teeth.
Nothing against the car but it certainly isn't the "EV" they would like you to believe.
My gosh! That's a mechanical hybrid, like a Prius. The gasonline engine can drive the wheels directly. It's not a pure EV with a range extender. You're right... they've been spinning a tale!
At least they are comparing apples to apples:
VOLT VERSUS PLUG-IN PRIUS:
THE BOAST: WHAT IT MEANS:
Volt's main electric motor is more powerful: 149-hp/273-lb-ft vs 80 hp/153-lb-ft Between its big motor and better gearing, Volt can provide the full range of performance, grade climbing, and top speed in electric mode. Prius must fire its engine to try to keep up with the Volt, and will still be left behind.
Prius's gasoline engine is more powerful: 1.8L/98-hp/105-lb-ft vs 1.4L/84-hp/92-lb-ft (est) Because of the way the Prius' planetary transmission works, the engine has to turn above 62 mph anyway, so Toyota depends on its gas engine to do more of the work.
Volt's battery pack is way bigger: 16kW-hr/435 pounds vs 3 kW-hr/330 pounds Volt provides 25-50 miles of real-world electric operation no matter how hard you flog it. If driven extremely gently below 62 mph, Prius can eek out up to 13 electric miles.
Prius burns Regular fuel, Volt requires pricier Premium or E85 ethanol Volt's 1.4-liter achieves a 5-percent efficiency gain by optimizing its combustion for high-octane fuel, because it most often operates at wide-open-throttle. (Its carbon footprint really shrinks on renewable ethanol!)
VOLT VERSUS PLUG-IN PRIUS:
THE BOAST: WHAT IT MEANS:
Volt's main electric motor is more powerful: 149-hp/273-lb-ft vs 80 hp/153-lb-ft Between its big motor and better gearing, Volt can provide the full range of performance, grade climbing, and top speed in electric mode. Prius must fire its engine to try to keep up with the Volt, and will still be left behind.
Prius's gasoline engine is more powerful: 1.8L/98-hp/105-lb-ft vs 1.4L/84-hp/92-lb-ft (est) Because of the way the Prius' planetary transmission works, the engine has to turn above 62 mph anyway, so Toyota depends on its gas engine to do more of the work.
Volt's battery pack is way bigger: 16kW-hr/435 pounds vs 3 kW-hr/330 pounds Volt provides 25-50 miles of real-world electric operation no matter how hard you flog it. If driven extremely gently below 62 mph, Prius can eek out up to 13 electric miles.
Prius burns Regular fuel, Volt requires pricier Premium or E85 ethanol Volt's 1.4-liter achieves a 5-percent efficiency gain by optimizing its combustion for high-octane fuel, because it most often operates at wide-open-throttle. (Its carbon footprint really shrinks on renewable ethanol!)
stopcrazypp
Well-Known Member
Even if the engine never directly powers the wheels, it is still a series hybrid. Now it is clear it is a parallel hybrid, which makes it not much different from a plug-in Prius. So the EREV thing is complete BS (IMO it was BS even without knowing the engine can directly power the wheels), even though this proves my (and many others') early point that having a direct connection is more efficient when in hybrid mode (seems like the engineers felt the same way).
also posted on ABG:
This car was always a plug-in hybrid, no matter how you cut it. EREV was always a marketing term. (Marketing and engineering rarely get along.)
When we first heard rumors that the Volt might get 50 mpg in charge sustaining (CS) mode, I was skeptical but thought it was great if GM engineers were able to pull it off since, to first order, serial is thermodynamically less efficient than parallel hybrid. Now that we get confirmation that the Volt is at times in a parallel mode, I'm unaffected by that information. Whatever is most efficient. From it's description, it sounds rather clever.
However, only 36 mpg in CS mode? That's the major disappointment. It shrinks the use case for this car. Sure you can take it on a long trip, but you're likely better off taking the Prius.
This car was always a plug-in hybrid, no matter how you cut it. EREV was always a marketing term. (Marketing and engineering rarely get along.)
When we first heard rumors that the Volt might get 50 mpg in charge sustaining (CS) mode, I was skeptical but thought it was great if GM engineers were able to pull it off since, to first order, serial is thermodynamically less efficient than parallel hybrid. Now that we get confirmation that the Volt is at times in a parallel mode, I'm unaffected by that information. Whatever is most efficient. From it's description, it sounds rather clever.
However, only 36 mpg in CS mode? That's the major disappointment. It shrinks the use case for this car. Sure you can take it on a long trip, but you're likely better off taking the Prius.
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I thought the point of a serial hybrid / range extender is that you design the ICE engine to run at its most efficient RPM / load. If it has to drive the wheels then you loose that advantage.
If it has 36 mpg (or even 50mpg) then from a European point of view its a bit pointless as we have loads of 4 door diesel engined cars that do more mpg than this. The VW polo does 83mpg (imperial gallons) which I think works out at 69mpg over the pond. Its not just slow eco cares that do better than the Volt - even a BMW 3 series diesel does better!
I know you dont have many diesel pumps at gas stations but is it only me or am I missing the point of the Volt?
If it has 36 mpg (or even 50mpg) then from a European point of view its a bit pointless as we have loads of 4 door diesel engined cars that do more mpg than this. The VW polo does 83mpg (imperial gallons) which I think works out at 69mpg over the pond. Its not just slow eco cares that do better than the Volt - even a BMW 3 series diesel does better!
I know you dont have many diesel pumps at gas stations but is it only me or am I missing the point of the Volt?
From what I've seen they can run the ICE at constant speed and use the gearing to vary the road speed. But yeah, 36 US / 43 Imperial MPG is poor when compared to the 70-odd MPG you can get with the similar performing BMW 320d. Then again I've rented cars with this 1.4l engine and seen even worse economy, so I'm really not surprised at all that they get these figures at cruising speed.
When this story was rumoured in the summer, I asked Vauxhall on their Facebook page about the Ampera and got the following reply:
Somehow I doubt it's a different design to the Volt.
When this story was rumoured in the summer, I asked Vauxhall on their Facebook page about the Ampera and got the following reply:
Somehow I doubt it's a different design to the Volt.
I've never been that interested in the Volt anyway since I'd like to loose the complexity of the ICE engine, but there is one reason why this is actually interesting.
First it violates the point some have made that the Volt could be made a pure EV by simply ripping out the range extender. That seems unlikely now from a technical standpoint, from a practical standpoint doing that would be madness.
Second one of the big advantages of a pure EV is you get direct drive with no complex gear box. Here the gear box is as bad as the Prius one for complexity.
Third it also means making a dieselpowered Volt will be difficult as well as a fuel cell version or a CNG version. You can't simply replace the range extender as the motor timings and probably lots of other stuff has to be adjusted as well.
Now add a high price in the US and an Ampera that might not even compete with a BMW 320d and you start to wonder why bother?
Cobos
First it violates the point some have made that the Volt could be made a pure EV by simply ripping out the range extender. That seems unlikely now from a technical standpoint, from a practical standpoint doing that would be madness.
Second one of the big advantages of a pure EV is you get direct drive with no complex gear box. Here the gear box is as bad as the Prius one for complexity.
Third it also means making a dieselpowered Volt will be difficult as well as a fuel cell version or a CNG version. You can't simply replace the range extender as the motor timings and probably lots of other stuff has to be adjusted as well.
Now add a high price in the US and an Ampera that might not even compete with a BMW 320d and you start to wonder why bother?
Cobos
^^^
All true. I seem to recall a "neither fish nor fowl" comment. Try to do two things, and you don't do either as well as if you just concentrated on the one.
Still, the Volt fills an important space in the marketplace.
All true. I seem to recall a "neither fish nor fowl" comment. Try to do two things, and you don't do either as well as if you just concentrated on the one.
Still, the Volt fills an important space in the marketplace.
Now we know that the tech is closer to the Prius than we thought, how does the price stack up against a plug in version of the Prius?
All things being equal, i.e. a bigger battery than is currently anticipated in the plug-in Prius I think the Prius may still be a smidgen cheaper.
For me the Volt is off the radar; there was something a bit nice about the concept of series hybrid that is now lost. Sure there are sound engineering reasons for their choices but I'd choose a Prius Plug-in as it feels more focused on aerodynamic perfection than the Volt and that'll take over in my mind as the selection criteria.
All things being equal, i.e. a bigger battery than is currently anticipated in the plug-in Prius I think the Prius may still be a smidgen cheaper.
For me the Volt is off the radar; there was something a bit nice about the concept of series hybrid that is now lost. Sure there are sound engineering reasons for their choices but I'd choose a Prius Plug-in as it feels more focused on aerodynamic perfection than the Volt and that'll take over in my mind as the selection criteria.
I have never been very excited about the Volt.
What else is GM not telling us?
Another rampant rumor is that they aren't really committed to it as a mainstream product.
Worries of EV1 all over again.
Then there are the stories of GM dealers wanting way over MSRP, but Nissan dealers charging under MSRP for the Leaf.
What else is GM not telling us?
Another rampant rumor is that they aren't really committed to it as a mainstream product.
Worries of EV1 all over again.
Then there are the stories of GM dealers wanting way over MSRP, but Nissan dealers charging under MSRP for the Leaf.
The Popular Mechanics "test" is bogus and unprofessional.
Driving the car at 78mph is not the standard freeway speed test. It may be a real world test but the EPA freeway fuel economy tests are done at 50 - 60 mph.
It is unprofessional to not disclose that and to not also test at the EPA standard, or provide comparisons to other cars under the same conditions.
They knew when publishing that people would take their "highway test" value of 36mpg and compare it to the EPA ratings for other cars.
I probably average 65mph in my Prius on the highway and at those speeds I only get 45mpg or so. At 78mph I am quite sure it will be under 40mpg, probably only in the mid 30s.
It is entirely possible that the Volt gets better mileage at steady 78mph than a Prius.
Is it $12k better than a Prius? Thats a much more complicated calculation - but at least lets not let the "professional" press cheat and lie on the very first thing they do.
Driving the car at 78mph is not the standard freeway speed test. It may be a real world test but the EPA freeway fuel economy tests are done at 50 - 60 mph.
It is unprofessional to not disclose that and to not also test at the EPA standard, or provide comparisons to other cars under the same conditions.
They knew when publishing that people would take their "highway test" value of 36mpg and compare it to the EPA ratings for other cars.
I probably average 65mph in my Prius on the highway and at those speeds I only get 45mpg or so. At 78mph I am quite sure it will be under 40mpg, probably only in the mid 30s.
It is entirely possible that the Volt gets better mileage at steady 78mph than a Prius.
Is it $12k better than a Prius? Thats a much more complicated calculation - but at least lets not let the "professional" press cheat and lie on the very first thing they do.
Its all about the details of how you drive.
Doctoring up an example that should be pretty favorable to the Volt...
Assume you drive 12000 miles in a year and 270 days you drive 35 miles and 17 days you drive 150 miles. ( On the other days you rest )
A volt that gets 35 mile pure electric range and 36mpg after will use 54 gallons of fuel and averages 220mpg over that year.
If the tank holds 10 gallons you will need to stop for gas 6 times ( 10 minutes each - 1 hour total )
A Nissan Leaf will require you to make 17 charging stops of 20-30 minutes ( level 3 ) ( 30 mins yields 8.5 hours total )
The Nissan Leaf is ~$8k less, and is likely to have a much lower cost of maintenance due to the much simpler drivetrain.
Even ignoring the cost of gasoline and extra maintenance on the Volt, over 5 years the Leaf pays you $213 per hour to plug in and charge.
Assuming level 3 charging is available, I think the Nissan Leaf is a clear winner over the Volt.
Doctoring up an example that should be pretty favorable to the Volt...
Assume you drive 12000 miles in a year and 270 days you drive 35 miles and 17 days you drive 150 miles. ( On the other days you rest )
A volt that gets 35 mile pure electric range and 36mpg after will use 54 gallons of fuel and averages 220mpg over that year.
If the tank holds 10 gallons you will need to stop for gas 6 times ( 10 minutes each - 1 hour total )
A Nissan Leaf will require you to make 17 charging stops of 20-30 minutes ( level 3 ) ( 30 mins yields 8.5 hours total )
The Nissan Leaf is ~$8k less, and is likely to have a much lower cost of maintenance due to the much simpler drivetrain.
Even ignoring the cost of gasoline and extra maintenance on the Volt, over 5 years the Leaf pays you $213 per hour to plug in and charge.
Assuming level 3 charging is available, I think the Nissan Leaf is a clear winner over the Volt.
EVNow
Well-Known Member
Volt makes sense even with low CS mileage. You drive in EV mode during your daily commute and you can use it for long drives as well. It would be a good car for a single car household.
It also makes sense to have it in a multicar household - with the other car being a BEV.
stopcrazypp
Well-Known Member
I'd still rather wait for official EPA estimates, since media drives are unreliable as a way to compare mileage. Although I don't think the EPA has finalized PHEV testing procedures and the final figures may come as a mix of charge-depleting and charge-sustaining modes, rather than distinct figures.
But if the final figures turn out to be the mid-30s for both city and CS driving, then that is very, very disappointing (even though it doesn't matter as much if you commute fits mostly in the AER).
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