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Will the Chevy Volt Succeed?

544 messages,  Last post on Oct 28, 2009 at 1:11 PM

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What is this discussion about? Chevrolet Volt, Automotive News, Hybrid Cars, Coupe, Hatchback, Truck, Sedan, SUV


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#368 of 544
Re: please dont drive on highway 40 miles [peralta] by reddroverr
Sep 24, 2008 (9:27 pm)
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Replying to: peralta (Sep 24, 2008 7:26 pm)

I'm assuming this is still valid. I am under the impression that the Volt would be able to run indefinitely on ICE power...converted to electric..as the battery runs down. Not sure how to square that with your power loss assumptions.
 
How Does It Work?
 
The Chevy Volt will use a new powertrain that GM is referring to as the "E-Flex" system. It uses electricity to move the car at all times, and uses an engine as a generator to repenish its batteries. To charge it, owners will plug it into a standard household electrical outlet. When they drive the car, it will use only its electric motor, no matter what speed it is driven, until its battery has less than 30 percent of a full charge remaining.
 
At that point, a small four-cylinder engine will turn on. That engine will not directly send power to the wheels -- instead, it will act as a generator, recharging the batteries.
 
According to GM Vice Chairman Bob Lutz, the Volt will use its GPS system to determine how long to run that engine. "The car will know how far you are from home," Lutz told reporters in September, "and it will only run the gas engine long enough to give you enough charge to get you home where you can actually plug it into the wall outlet. So the car will be smart enough to know where its home base is."
 
GM engineers estimate that the average driver will be able to travel 40 miles before the gasoline engine even ignites. But the range of the Volt under battery power alone will change based on how much weight it is carrying, how fast it is traveling, and other factors. The 40-mile figure is significant, however, because most Americans drive less than 40 miles per day. For many owners, the Volt would function as an electric car virtually all the time, using gasoline only when they took longer trips than they take on a typical day

 
http://usnews.rankingsandreviews.com/cars-trucks/2010-Chevrolet-Volt/
#369 of 544
Re: please dont drive on highway 40 miles [peralta] by peralta
Sep 24, 2008 (9:58 pm)
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Replying to: peralta (Sep 24, 2008 7:26 pm)

There should be a travel distance algorithm mode switch.
 
One is for the regular 40 mile or less per day usage before recharging,
 
second is for Max fuel economy mode with up front display of range before battery is depleted, for travels > 40 miles and
 
third is for Max battery range with same up front display of range before battery is depleted, for indefinite all day long travel.
 
OR
 
You have the option to enter data into the car on how many miles you plan to travel for the day then the car will automatically calculate for best usage of power between battery and ICE.
 
OR better
 
You enter your intended travel for the day in the car's navigation and the car calaculates for itself the total distance to be travelled.
 
If you ran out of battery prematurely, you will be driving inefficiently on ICE while dragging along the heavy dead batteries.
 
The ICE is most efficient if the car is already in motion since it doesn't have to inefficiently channel energy through the batteries.
 
The ICE would even be more efficient with almost 100% transmission efficiency if there is a clutch for direct mechanical drive, ideal for indefinite highway driving.
#370 of 544
Re: please dont drive on highway 40 miles [peralta] by eaton53
Sep 25, 2008 (3:09 am)
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Replying to: peralta (Sep 24, 2008 7:26 pm)

"I would guess that driving the volt with the ICE and with empty battery would be a terrible waste of fuel especially on the highway. Much worse than a regular car."
 
They're saying 50mpg. If it hits that number it will be much better than a regular car.
 
There is also talk of using On-Star so your Volt will always know how far it is away from home and attempt to to optimize its operation.
 
I have a 19.2 mile each way commute... a nearly ideal Volt distance. I'm sure the engine would run occasionally, which is not necessarily a bad thing. It keeps things lubed and the gas fresh. Volts should have a program that runs them occasionally for that reason, even if you never exceed battery range.
 
I'd think people considering Volts would ask themselves how often they would go over 40 miles without having charge access. For something like 80% of the population the answer would be "not often".
#371 of 544
Re: please dont drive on highway 40 miles [peralta] by tpe
Sep 25, 2008 (4:50 am)
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Replying to: peralta (Sep 24, 2008 9:58 pm)

The ICE would even be more efficient with almost 100% transmission efficiency if there is a clutch for direct mechanical drive, ideal for indefinite highway driving.
 
That would be the most efficient way to use the ICE but I think it would add complexity, weight and cost. The ICE is not going to be powerful enough to be the sole source of propulsion in some driving conditions, eg accelerating, going up a grade. So you'd need the capability of being able to supplement the ICE with the electric motor. I think your previous suggestion where the ICE generator directly powers the electric motor and uses it's occasional surplus to keep the batteries at 30% SOC has a lot of merit and it doesn't sound like a monumental engineering feat to accomplish this. Who knows, maybe the Volt will be doing this to some extent. In addition to it's greater efficiency it would reduce charge cycles on the battery pack. However you'd still want to only operate the ICE in a narrow power range that represented it's peak efficiency.
#372 of 544
Re: please dont drive on highway 40 miles [tpe] by peralta
Sep 25, 2008 (7:29 am)
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Replying to: tpe (Sep 25, 2008 4:50 am)

"That would be the most efficient way to use the ICE but I think it would add complexity, weight and cost"
 
Not necessarily. Things quickly becomes complicated if it is multispeed transmiision but not in a single speed gear reduction system. Single speed gear reduction system is almost always used by electric motors to power the wheels (except for in-wheel motors). That same gear reduction can be shared with the ICE.
 
"However you still want to only operate the ICE in a narrow power range that represented it's peak efficiency. "
 
A 1.4 L turbo gas engine will probably make efficient horsepower from maybe 15 hp to 70 hp. Below 15 hp requirement as in stop and go, that is taken cared by the battery power and the engine is off (like the prius).
 
Steady highway speed needs 15-30 hp. Assuming it has one fixed mechanical gear (as in top gear of a regular transmission), the electric motor will shoulder the extra boost needed for acceleration.
 
In that case. say you want to drive all day long. The distance all day would probably 600 miles (60mph average over 10 hours).
 
40 miles of that distance will be handled by battery and 560 miles will be petrol. The battery part will take care of the stop and go situations and also on the occasional additional boosts on the highway.
#373 of 544
Re: please dont drive on highway 40 miles [peralta] by eaton53
Sep 25, 2008 (8:31 am)
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Replying to: peralta (Sep 25, 2008 7:29 am)

I'm pretty sure it's the way it is because future Volts won't have an engine if fuel cells become viable.
#374 of 544
Re: please dont drive on highway 40 miles [eaton53] by tpe
Sep 25, 2008 (8:34 am)
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Replying to: eaton53 (Sep 25, 2008 8:31 am)

That's a good point. But the fuel cell could still send some of it's electricity directly to the motor and bypass the battery.
#375 of 544
Re: please dont drive on highway 40 miles [peralta] by tpe
Sep 25, 2008 (8:45 am)
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Replying to: peralta (Sep 25, 2008 7:29 am)

In the configuration you are describing the Volt would actually have more available power after the first 40 miles because now it could tap into the electric motor and the ICE for propulsion. Unless you are suggesting that the car also be able to access the ICE during the first 40 miles. The whole point of this car is to burn zero gasoline for most trips so I don't see that happening. Plus this car would correctly be called a hybrid at this point, which would probably disqualify it from some of the tax credits now being considered.
#376 of 544
Re: please dont drive on highway 40 miles [tpe] by eaton53
Sep 25, 2008 (11:12 am)
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Replying to: tpe (Sep 25, 2008 8:34 am)

I'd think most of the power will go to the motors and some to the battery to maintain a minimum charge. At that point the battery should be there to smooth out the highs and lows and capture free braking energy. If an engine is the power source since you really want to run it in a narrow, very efficient range.... hopefully one where the use of HCCI becomes possible.
#377 of 544
Re: please dont drive on highway 40 miles [eaton53] by tpe
Sep 25, 2008 (11:40 am)
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Replying to: eaton53 (Sep 25, 2008 11:12 am)

I think you are right. Until recently I was under the impression that all the power generated by the ICE went straight to the battery pack, which would have been horribly inefficient. On the other Volt thread I was directed to a link which confirms what you're saying. For some reason it seems that there are Volt enthusiasts who feel somehow duped by the fact that the ICE will only maintain a charge rather than recharging the battery pack. I can't understand why anyone would object to that.
 
With that said I don't quite understand the significance of OnStar or using GPS for calculating the distance to your destination/home. If once the battery pack is depleted to 30% it is maintained there what does it matter how far you are from home?

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