Chevy Volt Powertrain
It may surprise you that considering how important the Volt is to General Motors, the company does not build its electric motor.
Clearly GM played a major role in designing and engineering that motor as it appears to be unique in the industry. It is actually composed of two motors. The more powerful one acts as the primary driver traction motor, and the other acts as a generator to retrieve kinetic energy during braking and coasting. At times, if needed, both motors can act in parallel, and the system has an electronically limited 111 kw maximum output (150 hp).
The company supplying the Volt motor to GM is unknown. “We haven’t announced that yet,” states Volt spokesperson Rob Peterson.
GM is very serious about the future of electric cars, and doesn’t plan to source its motors indefinitely.
According to a report in USA today, later this month GM will be announcing plans to build or operate its own plant to build motors for electric cars. This announcement will possibly take place at the Washington DC Auto Show which opens on January 27th. Likely the DC initial market announcement will be made then as well.
GM already has opened its own battery assembly plant. Electric motors, according to GM vice chairman Tom Stephens is the “second leg of the stool” for electric cars.
The third leg is the power electronics that control the manner in which the battery and the motor interact.
Stephens didn’t specifically say if GM plans to build those in house as well, but presumably they will.
“Electric motors, batteries, power-control electronics — you need core expertise in those,” he told USA Today.
Source (USA Today)
This entry was posted on Saturday, January 16th, 2010 at 8:34 am and is filed under Electric Motor, Production, Voltec. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.
+17
Jan 16th, 2010 (8:45 am)In for a penny, in for a pound!
This just shows the total level of commitment that GM has in the Voltec platform. GO GM!
Be successful!
Tagamet
LJGTVWOTR! NPNS!
+6
Jan 16th, 2010 (8:50 am)This is another step in the right direction. Owning the core technologies will go a long way toward securing GM’s leading role in the future of EREV and pure EV vehicles.
+2
Jan 16th, 2010 (8:53 am)I was reading about how vehicle emmissions seem to be contributing to health issues, such as asthma in children here:
http://www.greencarcongress.com/2010/01/hei-20100116.html#more
So even if AGW is determined to be a hoax, there is a growing awareness that fossil fuel emissions are bringing misery and death to many. GM can probably come out with a lighter more powerful and efficient traction motor in generation 2, and that will happen sooner rather than later if GM actually makes the traction motor and thus possesses the core competence.
+2
Jan 16th, 2010 (8:56 am)You touch on one of our strengths here – there are SOOOO many good reasons to go electric (and none much better than helping kids! (JMO)).
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+4
Jan 16th, 2010 (9:08 am)100% agreed with GM on this provided they stick to their decision and develop and build their EV components in the U.S. It is imperative they have their finger on how the components for this new kind of car are made and designed. That’s extremely difficult if they are sourced a few thousand miles away IMO.
+1 to GM
-30
Jan 16th, 2010 (9:08 am)(click to show comment)
+2
Jan 16th, 2010 (9:10 am)+1 The more GM takes on “in house” the more control they will have on bringing the costs down (and profits up). Both are necessary for electrification by GM to flourish.
Great point!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (9:18 am)Wow! This is really good news. It cements GM’s commitment to electrification. My respect for GM continues to go up. Now, if they could just get a dealer near me to seem to know anything about the Volt. Well, off to the auto show.
-1
Jan 16th, 2010 (9:23 am)It seems hat GM is mimicking Renault which seems already controlling the three components see :
http://www.renault-ze.com/befr/
Best regards,
JC NPNS
Jan 16th, 2010 (9:24 am)TAKE LOTS OF PICS!
Congrats.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (9:27 am)Nice site! I loved the pictures (g). I’ll have to take your word on the content though.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (9:27 am)That reminds me. Lyle was going to have a list of official dealers here. There was a tab set up and everything. But it seems to have disappeared just when things should be getting close. What’s going on there?
+1
Jan 16th, 2010 (9:29 am)Even as we all grow older, we become increasingly prone toward getting mild asthma from all the different sorts of pollution “insults” as they are termed in medicine.
These technical advancements at GM really prove the “all out” acceleration to electrification.
At this astonishing apparent rate, a few years from now, it may be that internal combustion education may start to be decreasingly relevant in one sense for the consumer, yet ironically, increasingly relevant for advanced training for an even more complex trend to require all levels of advanced competencies at independent auto repair facilities and elsewhere. (Or, they go out of business faster).
Too many believe that advanced education is merely a purchased commodity (the less anyone knows, the less the belief of a percieved need to know more), that they can just sigh up for, take a few hours of training, and they will be “up to speed”.
Not quite that easy.
Learning of Advancements of all kinds require a particular kind of loyalty to a new process of observation that takes very many hours of direct intervention person-to-person on real problems solved, in order to prove the value of the process. At least 8 months of relentless usage of any new process is needed to systematically establish effort-capacity with that process, is critical.
This site is the most exceptional process for the education of the public and for the public good anywhere on the planet.
Readers who remain loyal followers of this site are getting the Volt education (and BEV education) that they need as forward-planning individuals, businesspersons, and wise governmental officials.
Jan 16th, 2010 (9:29 am)GM to build it’s own electric motors?
Hmmmm…..
I wonder if the Volt’s electric motors are currently made by Remy ? Remy is based in central Indiana and has been talking recently about a major expansion. I would first expect GM to form some partnership with a company like Remy to build exertise in this area.
AC Propulsion and UQM (once called Unique Mobility) may have been involved in the Volt (again, just a guess).
+3
Jan 16th, 2010 (9:30 am)I’ve seen several references in discussions of the Volt’s traction & generator motors to GM’s FWD 2-mode transaxle they developed a few years ago jointly with Daimler & BMW ….and used briefly in the 2-mode VUE. One even mentions that the housings are very similar, suggesting the Volt’s motor/generator might borrow parts of the FWD 2-mode design. We know the FWD 2-mode contains 2 separate electric motors having a total of 150 HP. And here Lyle describes the Volt as having 2 separate motors with a 111 kw maximum output (150 hp).
If I recall correctly, the FWD 2-mode transaxle was manufactured at a GM plant in Baltimore. Could GM announce the Volt’s “electric transaxle” will be made in the same Baltimore plant when they’re at the nearby Washington DC Auto Show on this Jan 27?
Jan 16th, 2010 (9:35 am)ABSOLUTELY! Including Leaf, etc.
+4
Jan 16th, 2010 (9:35 am)“The more powerful one acts as the primary driver traction motor, and the other spins in the opposite direction acting as a generator to retrieve kinetic energy during braking and coasting. At times, if needed, both motors can act in the same direction in parallel…”
————————————————–
I’ll be eager to see one of those full color cut-away drawings like they have in Popular Mechanics to get a grasp of how this all works.
It sounds like they have some geniuses at work at GM.
+1
Jan 16th, 2010 (9:36 am)Lyle, Can you expand on the two motor design? Do you know something that has not been published yet?
All other EVs use the same motor for regen. Why have two? More moving parts, more things to break down, more cables, more, more, more.
Of course, for every design there is usually a very well thought out reason. So, can you share? Is one of these coupled to the ICE? If so, are they in some way coupled together?
Maybe it’s still a trade secret. If so, I guess we’ll have to wait a year or so for someone to do the teardown.
Anyway, great job keeping the interesting articles coming. I hope GM gives you an assistant so you don’t get your medical licence revoked.
This is the year the marketing machine starts to crank.
+4
Jan 16th, 2010 (9:38 am)I agree this is great news.
I get my oil changed at a Chevy Dealer. At first they didn’t know about the Volt. Every time I go, I look for the Sales Manager and remind him I have cash burning a hole in my pocket waiting for the Volt. He tells me I’m not the only one telling him this and he’s thoroughly convinced he’ll be selling lots of Volts if the supply is there.
NPNS!
+5
Jan 16th, 2010 (9:42 am)______________________________________________________
From Lyle’s Article:
“Electric motors, batteries, power-control electronics — you need core expertise in those,” he [GM vice chairman Tom Stephens] told USA Today.
————
If,
Electric Cars increasingly become Electronic Appliances from a manufacturing standpoint meaning that manufacturing an Electric Car will become like manufacturing a TV, Computer, or Cell Phone…
And,
If with regards to the Electric Car major power-train components (electric motors, batteries, power-control electronics),
GM = Do it all in-house
Tesla = Final-Assembly in-house but components outsourced.
Fisker = All outsourced.
Which Electric Car Company business model wins?
______________________________________________________
+2
Jan 16th, 2010 (9:43 am)Roy, I think it is more complicated than that. Take the following with a grain of salt because they are just my (somewhat educated) assumptions and don’t represent any direct knowledge of precisely what is happening with the Volt… There are lots of motors in any car but of course the ones we are primarily interested here are the ones that move the car, stop the car, or generate current. I think those are either 2 or 3 motors depending upon how you define a “motor”. The ones this article talked about are the ones actually attached to the wheels. In this case it is one unit mechanically but electrically it is actually two motors built together. This is done for efficiency reasons with the traction section being much larger than the generating section. But either section can be used for traction or generation just at reduced efficiency from its primary function. So one might talk about two motors in the vehicle meaning the one attached to the engine and the one attached to the wheels. Or one might talk about 3 motors with one attached to the engine and 2 (1 unit) attached to the wheels. The article says side by side but I doubt (don’t know however) that is the case. I believe they are incorporated into one physical device thus the confusion.
Jan 16th, 2010 (9:46 am)Does anyone know what exactly is unique about GM’s motor, other than it is two motors to more effectively capture braking energy?
Jan 16th, 2010 (10:00 am)That, of course, would be the same Renault that is very heavily partnered with Nissan. Taken together, they would be # 4 on the list of vehicle manufacturing companies by volume (Toyota, GM, VW, Renault/Nissan, Ford)/2008 data
http://en.wikipedia.org/wiki/Automotive_industry
http://www.renault.com/en/Groupe/l-alliance-renault-nissan/Pages/l-alliance-renault-nissan.aspx
Jan 16th, 2010 (10:05 am)One important thing not all traction motors may benefit from is the oil bath the Volt’s “electric transaxle” housing provides. Like an automatic transmission’s housing, its internal components are lubricated (and cooled) by this oil bath as well as fully protected against moisture or road dirt/scum by this completely sealed housing.*
*My 2008 Vue’s tranaxle is so well sealed its oil sump has NO dip stick and NO transmission fluid scheduled changes.
+2
Jan 16th, 2010 (10:09 am)Here is a paper on a 2-mode Saab. See any similarities to the Volt? (ICE/transmission layout).
See the motors for the 2-mode in a cutaway on slide 23. It illustrates the 2 motors and the planetary gear sets that provide the electronically variable gear ratio (by changing the relative speeds of the motors, the gear ratio changes).
http://www.gamenetwork.se/gamearrangerar/referat/Energisession2007/Session6_ME.pdf
In Lyle’s test drive of the plug-in Vue, it was mentioned that the plug-in Vue was using the same power electronics as the Volt.
Here is some info on the plug-in 2-mode Vue. Note the cutaway of the FWD 2-mode on slide 3. It has 2 actively-cooled PM motors, 2 planetary gear sets, and 4 clutches.
http://www.che.ncsu.edu/ILEET/phevs/plug-in_2008/1A-1_GM%202-ModePHEV%20VUE.pdf
So is GM using a nearly identical system to the 2-mode, with its electronically variable gearing, and with one motor sized larger for the traction requirements?
Jan 16th, 2010 (10:12 am)Somehow I doubt it is a ridiculous idea. GM has built many working electric vehicles.
Jan 16th, 2010 (10:24 am)Thanks BillR! These are both excellent references to the 2-mode “electric transaxle” as I’m calling it here. I share your view that the Volt may use very similar designs to those your references depict, or at least important design concepts from them.
Jan 16th, 2010 (10:29 am)The big main motor is a 360 volt/ac 3 phase motor which physically turns the front wheels through the differential gears. The other motor is physically attached to the ICE an is a combination motor/generator. The motor/generator is the one that starts the ICE and acts as a generator to retrieve kinetic energy during braking and coasting
Jan 16th, 2010 (10:29 am)Now THAT would be a great announcement, on a lot of levels!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+1
Jan 16th, 2010 (10:47 am)Unfortunately, that may be where the Volt’s picking up a lot of it’s “rumored” 3900 lbs. The 2 mode transaxle looks to be one heavy son of a gun. Hybridizing the Saturn Vue added 398 (3867 to 4265) pounds where Hybridizing the Escape only 133 (3536 to 3669) pounds (2009 model comparisons).
http://www.examiner.com/x-572-Auto-Review-Examiner~y2008m10d22-Driven-2009-Saturn-Vue-2-Mode-Hybrid-car-review
http://www.motortrend.com/cars/2009/ford/escape/specifications/index.html
http://www.saturn.com/vue/specs-features/
/ I still think they should have built the 2 mode vue plug in. You’d probably average 60+ mpg at the end of the year, and it’d be with something that could tow 3500 lbs. That’s something nobody else has.
+1
Jan 16th, 2010 (10:54 am)I’m guessing that there are 2 sets of windings in the same motor. But could be a lot of things. Could actually just be 2 separate motor windings that share the same shaft.
Im off to the show… maybe I can get some more detail
Later
Jan 16th, 2010 (10:57 am)Take pics!
Congrats.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (10:58 am)nasaman had been drooling about this one!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (11:12 am)Yep, it’s a shame GM killed off Saturn, leaving the 2-mode Vue and (more importantly) its plug-in version as orphans. But who knows, maybe the design will finally show up in Caddy’s flagship, the plug-in Platinum XTS?
+5
Jan 16th, 2010 (11:21 am)Ill take 20 AER on my Silverado Hell ill take 10 miles AER America runs on trucks , we want to truck responsibly. Everything in the country moves on trucks,even the fuel for your car. Im hoping the future generations of the volt tech will offer something no one else does ELECTRIC TRUCKS
Jan 16th, 2010 (11:42 am)#1
Second the motion. +1
Jan 16th, 2010 (11:44 am)#9
Oh, oh, the dreaded Carlos strikes again.
Jan 16th, 2010 (11:48 am)#3
Alas, too true. +1 for raising the issue.
Along some of the freeways in LA the asthma rate in children is at least twice the national average. And that’s to say nothing of the cancer, heart attack, stroke, COPD, low birth weight, and many more documented health impacts. Diesel exhaust is the worst actor of all, but car exhaust is a great villain as well.
Jan 16th, 2010 (11:49 am)Yes, but unfortunately the towing capabilities will pretty much never be used in that context. But nothing says it can’t show up in yet another vehicle. If it’s as great as we all think, it will not die easily… they’ll use it someday, or at the very least, improve on it further and use that iterations.
+2
Jan 16th, 2010 (11:52 am)I drool thinking about an electric version of my ’05 Sierra Extended Cab 4×4! But sadly, I don’t think I can afford the second mortgage it would entail.
(oh man, I’m kind of a “Donnie Downer” today, sorry guys).
Jan 16th, 2010 (12:01 pm)I missed something…
Is the new plant in the U.S. or Canada?
-19
Jan 16th, 2010 (12:08 pm)(click to show comment)
+1
Jan 16th, 2010 (12:09 pm)SMILE! I hear that GM is coming out with a car called the Volt – 40 miles AER and then a small engine seamlessly provides the electrons! You can charge the battery by just plugging the car in overnight. It’s really cool!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (12:10 pm)I don’t think that it is mentioned.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+1
Jan 16th, 2010 (12:21 pm)How far are you driving today? How much gas will you burn? Um, no fooling?
Jan 16th, 2010 (1:01 pm)Hi Bruce,
I’m not sure who these questions were addressed to.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (1:19 pm)So far today…
One way from work 17 miles
Registered my son for Little League 4 miles
Will go to the field and the gym later 5 miles
Back to work later today 17 miles
43 miles total for today
Two opportunities to charge at work (free).
One opportunity to charge at home.
Total cost in fuel/electric equivalent?
$.50 in kw (home charge to go to work)
Gasoline used: none
43 miles distance for $.50
At $3 a gallon = 258 mpg
that’s amazing
=D~
Jan 16th, 2010 (1:30 pm)Lyle writes:
“… It is actually composed of two motors. The more powerful one acts as the primary driver traction motor, and the other acts as a generator to retrieve kinetic energy during braking and coasting. At times, if needed, both motors can act in parallel, and the system has an electronically limited 111 kw maximum output (150 hp).”
Lyle, where does this come from? It does not sound correct to me. Roy’s description above is how I always thought it works, namely:
-one motor generator attached to the ICE. It spins the ICE to start the ICE and then is driven by the ICE to generate electricity when the control system determines that is desirable. It is never mechanically connected to the wheels.
-one traction electric motor that drives the car wheels via a direct mechanical connection, and it will also put energy into the battery (i.e. charge the battery) during regenerative braking.
I do not understand the -14 by Roy’s comment. His last sentence may have been a little harsh, but he’s basically got it right, I think.
Jan 16th, 2010 (1:33 pm)Or, as Texas says above, Lyle, you know something we do not.
Jan 16th, 2010 (1:38 pm)Actually, Dave, by the methods GM uses, your mpg is infinite! Now that’s amazing!
Jan 16th, 2010 (1:43 pm)For anyone questioning where I learned that the Volt motor is actually two motors, its from the interview I did with the Volt Chief powertrain engineer:
http://gm-volt.com/2009/11/09/engineering-design-of-the-chevy-volts-two-electric-motors/
Jan 16th, 2010 (1:46 pm)Bill R. @ 25
Thanks for the links. Those are some good graphs, etc.
Jan 16th, 2010 (1:51 pm)Accurate too!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (1:52 pm)A repost of mine from a previous thread.
“If you look at the 11/9/09 post, Cattelan says this:
” in EV operation I have two motors on board and I typically use the traction motor only to drive the vehicle. However, I do have some mechanisms to couple those motors and in some points of operation these two motors can be coupled and have a more efficient state.”
She does say “EV OPERATION”, which may very well mean in “CD MODE”. If so, then she’s just saying that the generator is (in charge depleting mode) de-clutched from the ICE and is acting as an electric motor to drive the wheels along with the traction motor. That the generator acts as both a generator AND as a traction motor (but not as a traction motor when it’s engaged to the ICE (CS MODE). They are doing this to get better efficiency out of the electrical motor combination (thus using fewer kwh/mi while draining the battery in CD mode). I think this would explain everything she’s saying while still keeping the Volt’s series hybrid label intact.”
http://gm-volt.com/2009/11/23/engineering-design-and-efficiency-of-chevy-volts-generator-mode-builds-on-gms-two-mode-hybrid-technology/
/It’s just IMO base off of some things we’ve heard.
Jan 16th, 2010 (1:54 pm)That entry generated huge discussion, quite a level of controversy, and no subsequent articles to clarify.
Jan 16th, 2010 (1:55 pm)Off topic, but I like to look at this list once in a while. The electric cars ARE coming:
Plug-In Vehicle Tracker: What’s Coming, When
http://www.pluginamerica.org/vehicles/
+1
Jan 16th, 2010 (2:07 pm)#39
Maybe in a Chevy Coloradoesque truck which I wll need eventually to replace my S-10. One can only hope.
Jan 16th, 2010 (2:07 pm)The problem, Lyle, is that there are too many interpretations (as well as some incredulity) about what Alex said.
Carcus1′s interpretation above is just one of many.
I personally found what Alex said to be confusing and contradictory. And I’m a practising professional engineer wirh 30 years of experience.
Maybe this is all about Lutz’s secret transmission
There’s a scoop here for you Lyle, if you can get a real clarification!
Jan 16th, 2010 (2:14 pm)Yeah, excellent site. Calcars.com is another one (and they link to here quite a bit). Felix Kramer’s newsletters are ok, but he’s definitely been a strong advocate of plugin conversions.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+8
Jan 16th, 2010 (2:20 pm)The problem is this area is treading very deeply into GM proprietary information that they don’t want competitors to know.
In fact, during that interview the communications person held Alex back from going into more detail.
+2
Jan 16th, 2010 (2:21 pm)If an engineer can be confused, then I don’t feel *quite* so bad (g). I’ve struggled with both articles, but I attribute the “unknowns” or confusion to GM’s proprietary tech that by definition they don’t WANT to be clear. Doing so at this point would be kinda foolish. JMO
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (2:22 pm)Our posts crossed (lol).
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
-1
Jan 16th, 2010 (2:27 pm)Excellent questions! I’m not a huge fan of outsourcing because the manufacturing knowledge base for your product is entrusted to other compan(ies). However, government intervention (tax laws, safety laws, currency exchange rates, international borders, etc.) and public relations have turned “companies that make things” into fianancial coporations.
Jan 16th, 2010 (2:33 pm)“Conspiracy guy” thinks it might be a little more than coincidental that the 2MT70 basically disappears from view just when a whole biilion dollars worth of government funded research goes into a “totally new” EREV drivetrain.
/any bets on if the 2MT70 re-emerges at a later date it will be slightly changed, have a new nomenclature, and they’ll attribute it’s success to lessons learned in the volt development?
“Conspiracy guy” out
+2
Jan 16th, 2010 (3:59 pm)Perhaps the main drive motor is a switched reluctance type instead of a conventional 3-phase induction motor. An SR motor has few advantages in cost, weight and efficiency, but have not been widely used because of the complexity to control the motor.
Here’s a simple explanation
http://en.wikipedia.org/wiki/Switched_Reluctance_Motor
Modern signal processing electronics can do the controls at lower cost and are making these types of motors more popular.
Downside of SR motor is that it cannot act as a generator because the magnetic fields are not generated using permanent magnets.
This would fit the description in the article, but I don’t have any inside knowledge. Anyone out there know any more details?
Jan 16th, 2010 (4:05 pm)Interesting – Toyota FT-EV will use in-wheel motors. Thats another thing to think about while talking about inhouse motor manufacturing.
Jan 16th, 2010 (4:31 pm)Thanks Lyle. that explains the situation. But, I’m very interested in the whole story. It’s got to come out sooner or later. And I do hope you get the scoop!
Jan 16th, 2010 (4:55 pm)Kdawg, I think you got it. The big 150hp motor has two sets of windings, one optimized to provide maximum efficiency while normal operation and the second set of windings optimized for best energy recovery during braking.. both windings sharing the same rotor , shaft and direction of rotation.. while in sports mode both sets of windings are energized at the same time to provide maximum power.
Pros:
1. the second set of windings will give the Volt an extreme ability to recover otherwise lost brake energy, thus extending the range by recharging the battery. It also simplifies the implementation of the electronic brakes. This implies that range will not be affected by weight.
2. A single motor acts like two motors, giving the driver a burst of power on demand. Similar to cylinder deactivation used in some ICE engines or a two speed transmission. As a matter of fact, you could always add more windings and end up with motor with an electronic gear box.
3, increased reliability: the brake regen winding can be used to drive the car in an emergency, if the main winding/inverter fails. You will lose some range performance.. its a limp home mode.
Cons:
1. Cost.. now the Volt will need three inverters.. one to drive the main motor windings, the second to drive the brake regen winding and the third to drive the generator attached to the ICE.
2. the regen winding is optimized for braking, when you force it to drive the front wheels that will come with some losses in efficiency. usually a motor optimized for normal operation will not be as efficient as a motor optimized to be a generator. and viceversa.
Note that this kind of motor is not new in the industry, there are motor/generators with multiple staged winding/rotor riding on the same shaft.. usually very large multi kw motors.
Jan 16th, 2010 (4:55 pm)The plant is in New York State I think.
Tom
+1
Jan 16th, 2010 (5:05 pm)I’m really not that concerned about the configuration of the driveline. It must be clear by now that some advanced engineering is going into this project, so I’m pretty OK with whatever they come up with.
I just hope as hard as I can that the AER and the mileage on the “range extender” are good enough to justify all of the hard work and cost. If so, I don’t care if they power it with rubber bands. And if not, I don’t care how gee-whiz sophisticated it is. So:
LJGTVWOTR!!
Have a great weekend everybody.
+1
Jan 16th, 2010 (5:07 pm)The CEO’s and other managers deserve the lion’s share of the blame for their short term thinking by going for quick profits to assuage overbearing BOD’s and investors. The consumer’s wanting the cheapest price, regardless of quality and secondary benefits, are also greatly to blame.
Jan 16th, 2010 (5:07 pm)#69
So much the better. +1 Wouldn’t it be cool if they revived the mythical Tonawanda engine plant for this project. Home of the legendary “big block” Corvette engines.
+1
Jan 16th, 2010 (6:00 pm)Lyle certainly keeps our interest at a peak. The last few posts here at GM-Volt.com have generated a lot of interest; seen a lot of new blogers. Lyle’s timing is awesome; each new article captures our attention and also leaves us craving for more.
Great job Lyle!
Happy trails to you ’til we meet again.
Jan 16th, 2010 (6:10 pm)GM had traditionally controlled its suppliers cost accounting; this appears to be a partial change in practice although I’m not totally convinced it is a change. They, like other ICE manufacturers, have always built the engine that drives the car or truck. Although this type of motor, i.e. electric, has never been manufactured by an vehicle OEM before, doing so is a natural extension of their past practice. We will be able to make a definite statement if and when they take up manufacturing of control components in house. There are stile many more components that go into the car that are made out of house; IMHO, that will likely not change.
Happy trails to you ’til we meet again.
-10
Jan 16th, 2010 (6:23 pm)(click to show comment)
Jan 16th, 2010 (6:25 pm)Ron,
I believe you are correct.
All the information up to now that I have seen about regeneration used electronic circuitry to redirect the current generated when the electric motor slowed down. The magnetic field of the motor would collapse causing a reverse flow of current through the motor windings. The energy captured during this type of regeneration would only occur as long as the motor is rotating and likely wouldn’t recapture energy during the whole time the motor is slowing down.
GM may have designed this motor/generator to generate a charge during periods when the vehicle is going down hill. Since the generator is turning in the opposite direction compared to when it is working to provide traction, GM may (most likely) be using different control circuitry to direct the charge back to the battery pack. They may have found a simple way to capture more charging current during those down hill drives.
It sounds to me that they have a design that no one has thought of before.
Happy trails to you ’til we meet again.
Jan 16th, 2010 (6:39 pm)I’m with you!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (6:43 pm)Amen! +1
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+4
Jan 16th, 2010 (6:43 pm)I’m with you here, Noel. I honestly hope it all ends up being under promised and over delivered and not the other was around. I just want this car to be a total winner.
Jan 16th, 2010 (6:51 pm)I agree, nuclearboy!
During normal regeneration, the collapsing magnetic field causes the current to flow in the opposite direction in the motor. since the second motor functions as assist to drive the wheels and also to generate current to charge the battery, by reversing the direction of this motor, the circuitry would not have to compensate for the current reversing in the normal motor. Circuitry would only have to direct the current into the battery from this motor to the proper battery pack terminals. An AC to DC converter may be required depending on what type of motor this generator is.
As I said in an earlier comment, this may allow the capture of energy on down hill drives where normal regeneration would only capture energy while decelerating.
Happy trails to you ’til we meet again.
+1
Jan 16th, 2010 (6:53 pm)Seems to be working quite fine in current Volt tests.
Happy trails to you ’til we meet again.
Jan 16th, 2010 (7:00 pm)In the past it has been axiomatic that every manufacturer that hopes to make a profit must make their own ICE.. but the electric motor of a BEV is not the same as an ICE in this case.. motors can be made anywhere in the world with relatively low tech base required. The key to the future car manufacturer will be the battery cells, they have to capture the whole revenues stream for this critical item by manufacturing them.
Jan 16th, 2010 (7:23 pm)I generally agree with you except that many components of the motor/generator, battery pack, electric controllers, and other major assemblies will relie on many smaller companies that will remain in GM’s supply line. They have committed to building the battery packs, and now are about to announce building the electric motor/generators, and will likely manufacture major controller devices for their EVs.
True that every component that they can bring in house will lower their total cost but items like battery cells, bearings, and other items will continue to be made by independent smaller companies.
Happy trails to you ’til we meet again.
Jan 16th, 2010 (7:29 pm)That sounds right to me. A major chunk of the cost, and therefore a big piece of the potential profit, lies in the batteries. It would only make sense that the OEM’s who are serious about plug ins will try to bring this in house (or purchase a substantial stake in their battery partner).
Major Automotive manufacturers that own (or partly own) battery manufacturing**:
1. Nissan
2. Renault
3. BYD
4. Mitsubishi
5. Toyota
http://www.allcarselectric.com/blog/1020975_lithium-energy-japan-to-build-battery-factory-to-support-increased-i-miev-production
http://www.bloomberg.com/apps/news?pid=20601101&sid=agX_Y7U6vYMw
**list may be incomplete
+1
Jan 16th, 2010 (7:42 pm)Thanks Lyle!
It’s great to see that you are picking up on questions that came up during a previous post. there were many question about how they are coupled to drive the Volts wheels . So as I understand it now, there are three motors in the Volt: one attached to ICE to provide current for the traction motor, and two motors involved in driving the wheels, one of which also recharges the battery during deceleration. I hope my understanding of all this is now correct.
TIA!
Happy trails to you ’til we meet again.
Jan 16th, 2010 (7:52 pm)Right on, carcus1! +1. I missed your comment to that post. Thanks again for reposting your comment. You are right on spot with this observation. Makes my previous comment here plagiaristic. Glad to give you the credit for this insight.
Happy trails to you ’til we meet again.
Happy trails
Jan 16th, 2010 (8:04 pm)Thanks, Both links were good, I went through full PDFs
. Seems that power train is going on XTS.
I remember reading some place that GM started voltec design from 2 mode and by cutting down some parts. So i think most of the stuff like motors, electronics etc seems to be /will be identical.
Out of the track : GMINSide news put some shots of plugin Cruze , the plugin port looked like plug-in vues one.
Wondering which hybrid plugin power train is going in Cruze .
Second question is why GM has 2 plug standards than one J1772 ? do production will have only one ?
Jan 16th, 2010 (8:26 pm)Hybrid systems, plug-in hybrids, patents.
If you step back and look at the OEM’s for a moment, you realize that there’s only 3 that have successful hybrid systems (volume sales) thus far: 1. Toyota, 2. Honda 3. Ford; and only two of these( the two that are series-parallel) lend themselves to plug in possibilities (Toyota, Ford).
It’s quite possible that other OEM’s want to sell hybrids (and plug in hybrids) , but they just haven’t been able to develop a hybrid drive system that competes, and they don’t want to license from Toyota, Honda, or Ford.
/GM’s mild hybrid was a bust
//GM/Daimler/Chrysler/BMW 2 mode systems work, but appear to be complicated, expensive, heavy, slightly less efficient, but with the advantage of being able to tow.
+5
Jan 16th, 2010 (8:37 pm)hi Carl #75 …
Use of the Commercial Off-The-Shelf 1.4L (COTS) engine is a good thing. This engine is not carrying the weight of the vehicle. And it is never going to work hard. This engine should easily last the life of the car. Mild tuning for smooth quiet operation. Synthetic oil lubrication for infrequent maintenance and long life.
If GM used a hamster in an exercise wheel to generate electricity. The Volt will still produce 150 hp horsepower and 273 lb-ft of torque.
That’s not a misprint. 273 lb-ft of torque. Which other vehicles offer a similar torque rating?
2009 Nissan Maxima V6
3.5L Gas V6
261 pound-feet of torque
$31,000 22MPG
__________________________
2009 BMW 1 Series
3.0V Gas inline-6
200 pound-feet of torque
$30,000 21MPG
____________________
2009 Audi A4 2.0 quattro
2.0L Gas DOHC I4
243 pound-feet of torque
$33,500 (base) 23MPG
=D~
Jan 16th, 2010 (8:51 pm)Yes, I thought the same thing.
Either the description in the article is wrong, or there’s something else I’m missing here.
+1
Jan 16th, 2010 (8:57 pm)Scroll up. Basically, Lyle explained that there is proprietary tech info that GM is keeping under wraps.
HTH,
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+1
Jan 16th, 2010 (9:06 pm)hi DaveG #90 …
From what we have seen these last 15 months concerning the Voltec system. It really isn’t that complicated. I believe I understand what they are doing. As Tag mentioned. Let’s not talk too much about it at this time.
=D~
Jan 16th, 2010 (9:20 pm)How can that be? Are you saying that both motors are connected to the wheels? How else could the motor/generator that is connected to the ICE recover kinetic energy during braking and coasting?
Jan 16th, 2010 (9:21 pm)I agree.
Jan 16th, 2010 (9:34 pm)Here is a reason why one motor turns in a different direction as the other (a former post of mine).
———————-
After hearing how the Volt’s drive housing was similar to the 2-mode transmission, I started to do some research. It seem that the 2-mode uses a planetary gear set.
http://en.wikipedia.org/wiki/Global_Hybrid_Cooperation
More info is here:
http://en.wikipedia.org/wiki/Planetary_gearset
In the 2nd link, look at the gearset diagram in the upper RH corner of the page. The central gear in yellow is the sun gear. It meshs with the 4 planet gears shown in blue. The planet gears are held by the carrier in green, and the outer gear shown in red is the annulus.
For pure EV mode, let’s assume the annulus is fixed, and the traction motor/generator (MG2) drives the sun gear. This is a reduction gear, and let’s assume a 2:1 ratio. So for every rev of the sun gear (direct connected to MG2), the output shaft (green carrier) turns 1/2 rev.
A standard differential for the Corvette is a 2.56 final drive. So this equates to another speed reduction, combined equals 5.12. From one of my downloaded photos of the Volt, I could zoom in and read the tire size as P225/45R18. On the Michelin website, this tire rotates 802 rev/mile. Thus, in EV mode, MG2 would need to operate at 4100 rpm to drive the Volt at 60 mph (1 mile per minute).
Now comes the interesting part. GM states that in some modes, the 2-mode is electronically variable. So now let’s image that the other motor/generator, the one driven by the ICE (MG1), is connected to the annulus. So as MG1 rotates the annulus, the gear ratio changes. If the annulus is rotated in the same direction and same speed as the sun gear, there is no rotation of the planet gears, and the speed reduction is 1:1. This means that MG2 now only needs to operate at 2050 rpm to drive the Volt at 60 mph.
So by varying the relative speeds of MG1 and MG2, the gear ratio can be changed to put MG2 in its ideal operating zone.
For charge sustaining mode, a clutch between the ICE and MG2 can be closed, and the ICE will now drive the gearset, and ultimately the wheels. Speeds of the MG’s can be adjusted so to provide the optimum speed from the ICE. At 45 mph steady level cruise, the ICE may be controlled to 1200 rpm, and the excess shaft power used to generate electricity for the battery pack. Go up a hill, and after a period of time, the ICE speed changes and power is taken from the battery to provide boost. I expect the ICE will operate at or near full throttle at all times, with its power output controlled by MG1 and MG2 by modulating its speed.
So there is a possibility that gives the Volt an electronically variable speed transmission.
—————————
Jan 16th, 2010 (9:38 pm)Interesting ideas. I don’t believe this is how the Voltec system works. See you tomorrow.
=D~
Jan 16th, 2010 (9:44 pm)It’s all firmware. A motor and a generator are basically the same thing. Firmware pulses the electronic switches between the battery and motor. Varying these pulses will drive the motor forward, backward, or have the motor spin forward while recovering kinetic energy. That’s why I don’t like to call this an “inverter”. It’s much more complicated than that. It’s a motor controller. Very complicated low-level software algorithms here.
If you haven’t read this already, check out this link:
http://www.teslamotors.com/blog4/?p=45
Wally Rippel was the electric motor guy for the EV1 and the Tesla Roadster. In this article, he really gives a good overview of how car electric motors work.
Jan 16th, 2010 (9:54 pm)Yes, I’m familiar with the planetary gear system. The best explanation I’ve seen is the animation here:
http://www.wind.sannet.ne.jp/m_matsu/prius/ThsSimu/index_i18n.html
But GM has repeatedly said that the Volt’s ICE is not connected to the wheels.
Jan 16th, 2010 (10:00 pm)Well said! +2
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+2
Jan 16th, 2010 (10:04 pm)That made my head hurt.
/I’m just gonna sit here and play with my Spirograph.
http://www.openprocessing.org/visuals/?visualID=760
+1
Jan 16th, 2010 (10:09 pm)Your one eye is bleeding a little.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+5
Jan 16th, 2010 (10:11 pm)Sounds like the trolls are feeling neglected
+2
Jan 16th, 2010 (10:17 pm)LOL, trolls have needs too!
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
Jan 16th, 2010 (10:45 pm)You seemed to be on to something before, and it seems even more likely now. Great sleuthing and a nice explanation.
Too bad all this interesting stuff is on a Saturday when this site has less traffic, and a playoff Saturday to boot.
Kudos per usual to Lyle for coming up with very interesting stuff.
Jan 16th, 2010 (10:59 pm)Less than 10 minutes left in the game.
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
+3
Jan 16th, 2010 (11:57 pm)Carcus: That made my head hurt.
Me too. I must be needing to pull my gearset out of my annulus.
Jan 17th, 2010 (12:47 am)I agree.
The Voltec system probably (from engineering hints) doesn’t use any gear reduction to avoid gearing losses. It probably uses a plain fwd differential with the traction motor on the input shaft.
For the ‘we can use the generator to provide traction’ statements by Alex, it is probably all electronic. Something method like using a simple a/c motor to generate the third leg of three-phase. In other words, electronic phasing to provide a boost from the generator motor to the traction motor.
I think we are talking about two motors with their own windings (one a generator motor and the other a traction motor). Neither would necessarily need to reverse direction to provide brake regeneration. Energy from forward rotation can be recaptured.
My simple brain can’t conceive of how all this would work without ICE/generator decoupling (de-clutching). That’s for the Menlo Park crowd. However, I don’t believe de-clutching is needed.
In all cases. I want a Volt!
Jan 17th, 2010 (12:56 am)Amen! Let GM do their magic behind the curtain, just get the wheels on the road!
/night
Be well,
Tagamet
Let’s Just Get The ***VOLTS’*** Wheels On The Road!!**********NPNS
-3
Jan 17th, 2010 (1:07 am)This is a big mistake. Costs will increase per motor if they go in house. Union labor costs will balloon the cost of each motor and power electronics. They are better off investing in the company that makes them now to streamline their production and keep the Union out of the loop.
BIG mistake!
Jan 17th, 2010 (3:37 am)It’s easy to view each new detail through tunnel vision. Think it may be that the in house GM electric motors are being sized and optimized for automotive use? If this were not the case then GM would simply go to the lowest priced vendor.
The LG Chem battery for the Volt has both internal factory temp control. And a GM outer temp control system. We may be seeing the start of the same engineering with battery/electric motor units.
=D~
Jan 17th, 2010 (6:04 am)Bill the Volt does not use a Power Split Device like the Toyota and Ford systems use, the main traction motor is not connected mechanically in any way to the ICE generator, thus it does not matter at all if they turn in different directions. The Volt uses a serial architecture.
Jan 17th, 2010 (6:19 am)That list seems to be complete, Nissan/Renault are the same company. Ford could buy a chunk of A123 but that seems unlikely due to their impending money problems. I doubt LG will sell part of their company to anyone, they will hold on tightly to their core competency.
So it seems these four manufacturers see their future in electric cars. A possible way around this is if a standard single size/chemistry prismatic cell is used by many companies, this would allow massive mass manufacturing and lowest cost possible. This cell would become a classic commodity item.
We may still see the laptop cells become the most used cells in electric cars.
Jan 17th, 2010 (6:41 am)I would think that LG will give preference to Hyundai/Kia when things start to get HOT in the EV world. Are the Koreans as insular as the Japanese?
Jan 17th, 2010 (7:07 am)This seems to indicate that the Volt is not a series design.
That’s what I thought as well, until this article.
I see 3 possibilities:
1) That part of the article is incorrect.
2) The Volt has 3 motors, one connected to the ICE, and two for traction.
3) The Volt is not a pure series design, as we’ve been told.
Of these 3, I believe the first is most likely.
Jan 17th, 2010 (7:13 am)No, I don’t think so. Very different culture than Japan.
And from what I can tell, South Koreans have a generally favorable view of the U.S..
+1
Jan 17th, 2010 (7:30 am)If you have two electric motors, there are at least four synchronous variations in the internal magnetic timing of their usages. (Putting aside for a moment, all the mechanical stuff). And, (speculatively), if you can internally use more variations regarding the reversing of polarity (which happens at least in a simplistically-minimal fashion), and/or, in addition, a synchronization of the timing of increasing (and even decreasing) magnetic densities, (even opposing polarities) to such a refined extent, then, you have 16 possible synchronous variations for the electronic timing of all combined feild densities and coordinating of the ramp matchings of all those field densities. (Even to the extent to “load-removal-oil-gap, float cool” the gearset contact surfaces better).
These sorts of ways of thinking differently may be examples of the new ways engineers can apply these possibilities in a new artform of designing what I would call “polyphasic” electronically-synchronous electric motors.
Whereas for the last 100 years, trillions of dollars has been invested into internal combustion worldwide, the investment focus has begun to change over to incredible ways to design electric motor propulsion.
It is all going to change extremely rapidly now.
+1
Jan 17th, 2010 (7:54 am)+1 to that statement Dan.
LJGTVWOTR
HAS Plug? Have Sale.
Jan 17th, 2010 (7:56 am)Here’s how I understand the motor controller.
Each motor has 3 stator windings. Each stator winding has 2 connections.
The battery actually provides 2 taps, one at full voltage (around 400 volts) and another at half voltage (around 200 volts).
The motor controller (a.k.a. inverter) consists of many high power FET switches that connect the battery to the motor. When a particular FET switch turns on, current may flow in either direction, depending on which side of the connection has higher voltage at the time.
Each of the 3 stator windings is connected to the battery, at both voltages, and in both polarities. My guess is this would require 18 FET switches per electric motor.
The FET switches are controlled by low-level software (a.k.a. Firmware). The Firmware makes short pulse type connections to certain FET switches at certain times. By varying the width and timing of these pulses, the Firmware controls speed, acceleration, direction, regenerative braking and coast, etc.
Jan 17th, 2010 (8:12 am)Thanks for the plus one. Too bad my positive votes don’t always show up for some reason. Maybe to offset my negative votes for when I demand professionalism sometimes, but, I always appreciate being able to share experience.
We’ve not much more time to get carbon under control. The link I saw yesterday that was provided by GM Saab/Europe, shows a carbon proportion at 700 parts per million by the end of the century. America has got to start being far more responsible regarding this. China and India also need to be more responsible toward this as well. Electrification of the auto has got to be accelerated far far faster if we are going to leave an adaptable world to next generations. We are currently in the process of ending our own future existence.
This is why I back GM so completely here.
I was at a convention center here in Austin yesterday which hosted a small plug-in and green building show.
Some excellent GM reps were there explaining the 2 Mode system. They mentioned that the Volt might be coming to visit Austin at a larger convention center that we have here, sometime in May.
Really looking forward to that.
+1
Jan 17th, 2010 (8:15 am)Kind of like Walmart; buy the low price item from China and put the local businesses out on the curb. Americans need to wake up and start demanding quality from U.S. companies but need to start buying American made products.
Happy trails to you ’til we meet again.
P.S. GM, don’t disappoint us with less than high quality vehicles.
Jan 17th, 2010 (8:33 am)Here’s a couple of quotes from an AP-Wire/Yahoo article this morning regarding electric vehicles at the Detroit Auto Show:
_____________________________________________________
http://finance.yahoo.com/news/Hot-cars-in-Detroit-Small-apf-2949015233.html?x=0
The Nissan Leaf
“You will be able to buy one toward year-end, for about $30,000″.
James Bell, an executive market analyst for Kelley Blue Book, said the Leaf gives Nissan a public relations advantage over rivals because it’s fully electric at a relatively low price.
General Motors will begin selling the Chevrolet Volt about the same time the Leaf comes out. It can go 40 miles on electricity but has a gas engine to generate power when the batteries are depleted.
“A car that doesn’t even have an engine that can go 75, 80 mph for 100 miles, that just screams more advanced than the Volt is,” Bell said.
Jan 17th, 2010 (8:41 am)A related note from the Automotive hearings on capital hill. I saw people speaking that provide tooling and equipment to outfit a factory for auto production. This company supplied GM, Ford, and Chrysler but noted that the Japanese would not deal with them. The Japanese import all of this important equipment from Japan. They treat the Americans like unskilled labor who can help put the cars together only.
The same gentlemen noted that the Korean car makers do buy their equipment when they setup a factory in the US.
The Koreans do seem to treat us more fairly than the Japanese.
Jan 17th, 2010 (8:45 am)I was curious to know the collapse-rate of the fields as well as the maximum switch rates of the FET’s. If the fields are held at a minimum steady state of flux densities, then, to be more readily prepared for the next attraction (reducing rise time), that would make sense. Then, in that case, the other idea I had would be for a six phase motor concept (2 peak-flux-distance offset phase sets in one) , with something like a TRI-FET per phase, where the controlling stages could better take advantage of rise times and limited feild collapse time durations, as well as a finer tuning of the magnetic distances where the flux densities are strongest in both combined.
While Prius uses three large capacitors from one picture I saw recently, which I believe are for feild collapsing, the ideas I posted above was to have the different motors be far more electronically ramped in unison both up-load and down-load during feild activities for different and entirely new dynamic ways.
And, if you really want to “go over the top”, (Those radically-courageous BMW engineers might get tickled with this one),
******* a *nine phase electric motor* *******
(where you don’t always have to run all phases).
Jan 17th, 2010 (8:46 am)So far the USA has only spent 6 Billion+ on imported oil from OPEC and $15 Billion+ in total on imported oil.
Check out the third row from the bottom.
EV’s rock, in so, so many ways. What’s not to like?
http://www.usdebtclock.org/
Jan 17th, 2010 (9:24 am)First, accept that the Volt is a series hybrid; an EV that uses an ICE to turn a generator that creates the electricity to drive the traction motor The ICE never provides power to the wheels. What is going on here is the use of a complex motor and gearing, I believe, that combines two motors into one assembly. Thus, the Volt in fact has three motors. It is still a series design; only electric power drives the wheels.
Happy trails to you ’til we meet again.
Jan 17th, 2010 (9:34 am)Couldn’t edit this to say:
that combines two motors, gearing, and clutches into one assembly.
Happy trails to you ’til we meet again.
Jan 17th, 2010 (9:46 am)Lyle – great info over the past few weeks.
Jan 17th, 2010 (9:58 am)I found this link about ultra-capacitors used in the Prius. It may provide information that is relevant to this thread. As I understand it, ultracaps, are used where fast storage and discharge are needed. They are currently being used where short term storage is needed in the design of the vehicle traction system. They would store power obtained from regeneration that would shortly be used to start vehicle as in coming to a stop and then accelerating thereafter.
http://priuschat.com/forums/gen-ii-prius-technical-discussion/33297-ultracapacitor-use-prius.html
From the last comment to the poster’s question, it appears that the capacitor are used to insure braking.
Happy trails to you ’til we meet again.
Jan 17th, 2010 (10:37 am)Yes, that link is very helpful. It seems I was implicitly giving credit where it was not due with the Prius.
Reversing the polarity of capacitors using double FET’s (of the three FET’s) was where I was going with that thought process at post #122 (for a possible magnetic repelling concept in the same (propelling) or opposite (braking) torque direction in the other 3 phase set as another possibility for some circumstances).
But your post really helped me to get that last technical detail out here for my post #122.
Thanks for the link!
Jan 17th, 2010 (12:29 pm)Bringing motor production and development in-house is a good thing. This shows “real” commitment to electrification of the automobile, albeit only one small step in the process. I think it should be described as a four legged chair rather than 3-legged stool. Software control being the fourth leg. I still agree with GM’s decision to stay out of the cell development and manufactring business. The tech is moving too fast and in too many directons with cell costs too high to risk being stuck with the wrong tech. Confining their role to the elements of EREVs that are more directly related to their motive applications (battery packs, power electronics, motors, and control software) make the most sense for an automobile manufacturer right now.
Jan 17th, 2010 (6:54 pm)After reading all the comments, I guess there could be valid reasoning for greater complication. I still reject the “reverse spinning” concept, but there could be valid reasons for the traction motor to be designed as two motors on the same shaft. In normal operation, the efficiency of an induction motor is a function of power output. That is at full power it is very efficient about 98%, but if it is only outputting 5 or 10 hp then the efficiency could be much lower. There are various ways to combat this, one is purely firmware. Instead of lowering the voltage for low power the controller could go into a pulsed sine wave mode where a single half sine positive is followed by a short off period (coasting) then a half sign negative, and off period. This mode allows the peak power to remain high with high efficiency but lower average power. This method is the easiest as no modifications to controller or motor are required, just programming. Another method is to split the motor into sections so at low power only one section is running, again at high efficiency. Splitting the motor into sections raises the cost of the motor and electronics. There is however a bonus to splitting the motor, and that is the sections can be in parallel when full power is required and in series to capture more braking energy. This way there are three modes,
1. parallel = high power.
2. one half motor running only for low power.
3. series for regenerative braking.
Jan 17th, 2010 (7:31 pm)I was thinking about splitting the motor last night after I signed off.
One idea is to have one of them with a more narrow diameter core section than the other. But, the wiring would be separately controlled of course.
I’d bet GM has already thought of all this though.
Jan 18th, 2010 (12:17 am)No clutches, just a single gear that reduces rpm, plus the differential.. but the motor is optimized for two different modes.
+1
Jan 18th, 2010 (10:16 am)Just reading about torque ratings like this makes me weepy. My knees get all rubbery. Thats a respectable amount of torque, it would be useable at any boat launch I frequent. Unless I need to pull an LCM-6 off a sand bar, 273 lb-ft works for me.
I know, I know, there’s bigger ratings out there, but this is a sedan we are talking about.
+1
Jan 18th, 2010 (11:11 am)#119
Alas, too true.
Jan 18th, 2010 (10:57 pm)Using a reduction gear with the AC induction motor saves the expense, weight and complexity of having a transmission. Without the ability to reverse the polarity of the traction motor, how will reverse be actuated with only a simple reduction gear?
Jan 20th, 2010 (9:51 am)Yes, I believe that will be the case. The motor/generator will be physically hooked to the wheels to recover kinetic energy.
Jan 20th, 2010 (1:08 pm)I’m very excited to the Volt so close to production. Additionally I’m very proud of how the US auto makers are incorporating higher efficiency into vehicles, be it through hybrid technology or EREV, while at the same time improving on the quality of the overall vehicle lines. As a current Prius owner *ducks quickly* I am looking forward to my next vehicle displaying a Chevy or Ford symbol on the grill!
I’m proud of GM; I like what they are doing and the products that they have in the pipeline. I hope they experience tremendous success with the Volt and it’s sibling EREV vehicles. It’s good to see this kind of excitement and innovation in American products again, and to see industry leadership coming out of Detroit once more.
Go get’em GM!
Best regards,
Scott
Jan 20th, 2010 (6:50 pm)You mis-understand. Yes the polarity of power is reversed to make the car back up. The article says that there is a separate reverse spinning motor (while the car is going forward) for capturing braking energy. To have one motor spin in one direction and a second coupled to it spinning in the opposite direction requires gears. There is no need to spend money on gears when just reversing the wires on the motor would accomplish the same thing for no cost at all.
Jan 25th, 2010 (6:16 am)lets clear this up, regen braking does not mean the motor spins backwards.. it still spins in the same direction but with added drag that slows down the car. The wheels are driving the motor, not the other way around.. just the same way that normal brakes work. No gears or clutches are needed.