Sign in to follow this  
Followers 0
Drew Dowdell

Ya'll settle down now....

30 posts in this topic



What the Volt's gas engine can't do is completely recharge the battery pack to its full capacity. Rather, when load conditions are light the gas engine will send surplus electrons to the battery pack, which will also be receiving extra charge from regenerative braking, as well. That sounds about right to us, as we've always been told that constantly charging a battery to its maximum will shorten its life, as the optimum charge range is usually between 20 and 80 percent, not completely drained and not completely charged. GM is determining right now just how much it wants to let the gas engine charge the Volt's battery pack, but rest comfortably knowing that your future Volt won't be carrying around 400 lbs. of uselessness when the charge runs out.
0

Share this post


Link to post
Share on other sites

I think it will be wise to sit tight and see in November 2010 rather than being armchair critics or fanatics. Many things shall and will change be it good or bad between now and then.

At least it is good to know emotions (both positive and negative) are running high on this vehicle.

0

Share this post


Link to post
Share on other sites
An extra helping of crow for GXT.

Really? Why? I'm not sure what I wrote that you are referring to. Are you blaming me for believing the now-incorrect GM PR? I think this just confirms what I've been saying, that GM is making up a lot of this stuff on the fly. Yes, crow for me.

I never understood what the fuss was about here. Why would you want the gas engine to recharge the batteries? It just means you are using gas to recharge the batteries instead of electricity through the plug. Doesn't that defeat the point of the Volt? Isn't the goal to have the engine run as little as possible? If this was so desirable why not get rid of the plug entirely?

But for some reason people are spazzing out because the Volt wasn't going to do something you didn't want it to do anyways. And now people are happy because it does something you wouldn't want it to do. And apparently I'm supposed to eat crow about something.

And yes, when the charge runs out the battery is still pretty very nearly 400lbs of uselessness (keep in mind that the usable capacity of the battery to begin with is only 50% so the battery is always at least 200lbs of uselessness). Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

0

Share this post


Link to post
Share on other sites
...

Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

0

Share this post


Link to post
Share on other sites
Really? Why? I'm not sure what I wrote that you are referring to. Are you blaming me for believing the now-incorrect GM PR? I think this just confirms what I've been saying, that GM is making up a lot of this stuff on the fly. Yes, crow for me.

I never understood what the fuss was about here. Why would you want the gas engine to recharge the batteries? It just means you are using gas to recharge the batteries instead of electricity through the plug. Doesn't that defeat the point of the Volt? Isn't the goal to have the engine run as little as possible? If this was so desirable why not get rid of the plug entirely?

But for some reason people are spazzing out because the Volt wasn't going to do something you didn't want it to do anyways. And now people are happy because it does something you wouldn't want it to do. And apparently I'm supposed to eat crow about something.

And yes, when the charge runs out the battery is still pretty very nearly 400lbs of uselessness (keep in mind that the usable capacity of the battery to begin with is only 50% so the battery is always at least 200lbs of uselessness). Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

What part of "range extender" do you not understand?

0

Share this post


Link to post
Share on other sites
Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

Forget it, AAS: he totally misses the point. In his efforts to trash everything about the Volt (fear, perhaps?) he misses the point entirely. The 2-mode systems and the 'Synergy Drive' are overly complex. Why would you want 2 sets of drive systems? Why would you want a transmission (even a CVT) that continuously makes compromises between putting torque to the wheels and optimal fuel efficiency?

Perhaps the day will come when the Volt can run 300 miles on a single charge, but until that day arrives a small, efficient gas engine that operates only at one particular RPM as necessary is a beautiful compromise, to give those 30% of the driving public the ability to go beyond the 40 mile range that has been set as a target for the electric only mode.

Those with axes to grind are always shown naked in the face of facts.

0

Share this post


Link to post
Share on other sites
People were complaining about the styling, but this is not the car's worth.

It got plenty of attention at LAIAS, and I personally think it looks awesome, so I'm not worried. If the Prius sells on fuel economy alone, this machine should move units like the second coming.

0

Share this post


Link to post
Share on other sites
Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

That assumes it could ever be as optimal as the plug. And if that is the case then why bother with the plug at all? Just use the engine all the time.

The goal is to use the gas engine to keep you driving until you get to the next plug, not to replace the plug.

0

Share this post


Link to post
Share on other sites
What part of "range extender" do you not understand?

Do tell. What part of "range extender" involves chargine the batteries beyond what is needed to extend the range?

0

Share this post


Link to post
Share on other sites

I know I've watched way too much Beavis and Butthead when a phrase like 'range extender' has me giggling like a school girl.

0

Share this post


Link to post
Share on other sites
Do tell. What part of "range extender" involves chargine the batteries beyond what is needed to extend the range?

The system will keep the batteries somewhere between 20% and 80% charged. The NAV system is also suppose to be smart enough that it will know when you are headed home and only use the gas engine to charge the batteries enough to get you there.

0

Share this post


Link to post
Share on other sites
The system will keep the batteries somewhere between 20% and 80% charged. The NAV system is also suppose to be smart enough that it will know when you are headed home and only use the gas engine to charge the batteries enough to get you there.

Last told by GM it is actually 80 and 30. The ICE will attempt to maintain the minimum 30% state of charge for two reasons:

1) Deep discharges will shorten the life of the battery.

2) The ICE is unable to produce as much electricity as the electric drive will pull from the batteries. This could cause the car to go into a limp mode if there weren't sufficient reserves. Apparently it is still a possibility if you were going up a large hill, but it isn't overly likely to happen (e.g. 50% charge gets you ~32 miles on a flat highway with no AC. Going up a long incline at high speed with the heat on you could chew through that 30% reserve in perhaps 10 miles).

Last word from GM is that that Nav functionality will not happen. I believe the comment was something along the lines of, "Are you going to risk damaging your extremely expensive battery to save a couple dollars of gas?"

I just re-read my initial post. Perhaps replacing the "Why would you want the gas engine to recharge the batteries?" with the more explicit "Why would you want the gas engine to COMPLETELY recharge the batteries?" makes my meaning more clear.

0

Share this post


Link to post
Share on other sites
Forget it, AAS: he totally misses the point. In his efforts to trash everything about the Volt (fear, perhaps?) he misses the point entirely. The 2-mode systems and the 'Synergy Drive' are overly complex. Why would you want 2 sets of drive systems? Why would you want a transmission (even a CVT) that continuously makes compromises between putting torque to the wheels and optimal fuel efficiency?

I guess that is why the Volt will be so widely available, so inexpensive, so cost effective as compared to the Prius?

On the other hand, some argue that the Volt is an overly complex electric car in that it still needs the gas drivetrain, a plug, etc.

Perhaps the day will come when the Volt can run 300 miles on a single charge, but until that day arrives a small, efficient gas engine that operates only at one particular RPM as necessary is a beautiful compromise, to give those 30% of the driving public the ability to go beyond the 40 mile range that has been set as a target for the electric only mode.

There is no doubt that it is all about compromises and timing. As per the EV1, GM's timing still seems a bit off. The Prius and the Insight are the correct place to be right now. GM lost that battle and they are hoping to distract you with their fancy future-car instead.

Those with axes to grind are always shown naked in the face of facts.

I guess that would explain why you think the relatively available and inexpensive (and more importantly, infinitely more "existing") Prius is the complicated compromise and the Volt isn't.

0

Share this post


Link to post
Share on other sites
"Why would you want the gas engine to COMPLETELY recharge the batteries?" makes my meaning more clear.

I understood your meaning to be just that. The ICE won't completely recharge the batteries. It'll just get them to 80%. I'll concede that I was wrong about the 20% v 30% of the lower threshold, but my point stands.

0

Share this post


Link to post
Share on other sites
I guess that would explain why you think the relatively available and inexpensive (and more importantly, infinitely more "existing") Prius is the complicated compromise and the Volt isn't.

The Pruis is way overly complicated. Just because Toyota made it work doesn't mean it is the right way to go about doing it.

The Insight, and this is assuming the basic layout of the powertrain is the same as the current Civic hybrid, is actually the simplest design of all.

What is interesting about these two different hybrid models is that GM took some basic concepts from each one and assimilated them into their 2-mode hybrid design.

The Volt is still a completely new way of doing things and as such, it's untested. The most similar power train configuration out there would be Diesel-Electric locomotives, but the scale is so different as to not be relevant.

0

Share this post


Link to post
Share on other sites

IMHO that they have been playing with this kind of idea since the late 1930's with EMD makes a difference. It is a difference of scale, but perhaps some of the technology and ideas sury cary over, yes?

Chris

0

Share this post


Link to post
Share on other sites

The biggest difference between Electromotive and the Volt is the battery. In a locomotive the engines never shut off*

*GE has developed a hybrid locomotive and I'm not sure how that technology works yet.

0

Share this post


Link to post
Share on other sites
I understood your meaning to be just that. The ICE won't completely recharge the batteries. It'll just get them to 80%. I'll concede that I was wrong about the 20% v 30% of the lower threshold, but my point stands.

The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%).

The 80% state of charge is the maximum to which the PLUG will take the batteries.

The question still stands: Why do you want the ICE to charge your battery to 80%? That makes the plug useless.

It might also be worth mentioning that the ICE can only generate under half electricity that the the Volt can put to the ground. Therefore it isn't like the ICE is going to be generating a huge surplus of energy.

0

Share this post


Link to post
Share on other sites
The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%).

The 80% state of charge is the maximum to which the PLUG will take the batteries.

The question still stands: Why do you want the ICE to charge your battery to 80%? That makes the plug useless.

It might also be worth mentioning that the ICE can only generate under half electricity that the the Volt can put to the ground. Therefore it isn't like the ICE is going to be generating a huge surplus of energy.

If the ICE will only take the batteries to 80%.... and the plug will only take the batteries to 80%... doesn't that make 80% the new 100%?

To your last point, that only matters if you're at full throttle all the time.

0

Share this post


Link to post
Share on other sites
If the ICE will only take the batteries to 80%.... and the plug will only take the batteries to 80%... doesn't that make 80% the new 100%?

The ICE DOESN'T take the batteries to 80%.

I wrote: "The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%). "

Why are we having such problems communicating here?

The Plug tries to keep the battery 80% charged.

The ICE tries to keep the battery 30% charged.

In general, the Volt tries to keep the battery between 30% and 80% charged.

And the 80/100% distinction is important because, when combined with the 30% minimum, it means that the Volt really is really hauling around twice as much battery as it tries to use.

Edited by GXT
0

Share this post


Link to post
Share on other sites
That assumes it could ever be as optimal as the plug. And if that is the case then why bother with the plug at all? Just use the engine all the time.

The goal is to use the gas engine to keep you driving until you get to the next plug, not to replace the plug.

There doesn't need to be an assumption on the ICE being as optimal as the plug. Designing the ICE charging system to run at an optimal RPM is good/smart Engineering. The whole point of using the plug, besides it possibly being more efficient then the ICE, is that that electricity doesn't have to be produced using petroleum ('foreign oil') based energy sources.

...

And the 80/100% distinction is important because, when combined with the 30% minimum, it means that the Volt really is really hauling around twice as much battery as it tries to use.

It means that there is a FACTOR OF SAFETY! Once again, good Engineering will include a factor of safety (some level of over-Engineering, for the rare occasion that an application demands it).

0

Share this post


Link to post
Share on other sites
There doesn't need to be an assumption on the ICE being as optimal as the plug. Designing the ICE charging system to run at an optimal RPM is good/smart Engineering. The whole point of using the plug, besides it possibly being more efficient then the ICE, is that that electricity doesn't have to be produced using petroleum ('foreign oil') based energy sources.

It means that there is a FACTOR OF SAFETY! Once again, good Engineering will include a factor of safety (some level of over-Engineering, for the rare occasion that an application demands it).

Eh, it's done more because draining the battery below 30% or leaving it 100% charged on a regular basis dramatically shortens the effective life of the battery. It's one of the limitations of the type of battery GM chose to use for this project, but it's still the best compromise of size and power delivery that battery technology allows currently.

-RBB

0

Share this post


Link to post
Share on other sites

Your content will need to be approved by a moderator

Guest
You are commenting as a guest. If you have an account, please sign in.
Reply to this topic...

×   You have pasted content with formatting.   Remove formatting

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

Sign in to follow this  
Followers 0



  • Who's Online (See full list)

    There are no registered users currently online

  • Who's Chatting

    There are no users currently in the chat room