The Chevy Volt’s 1.4 L 4 cylinder flex fuel generator garners a lot of attention and discussion online.
It is this range-extender that make the car so unique. Although the Volt always operates as an EV, once the battery’s state of charge reaches roughly 30% this generator powers on, providing electricity to the motor. Energy is also obtained from regeneration and the battery buffer when power demands are high.
GM has yet to publicly demonstrate the car operating in this charge-sustaining mode, but most accounts indicate it is unnoticeable.
In spite of many months of rampant speculation here, GM’s lead Volt engineer Andrew Farah has finally disclosed some details about the engine’s operation. He said the generator would “operate from 1200 to 4000 RPMs and from a 30% to 100% load.”
Further explanation comes from Volt Powertrain Engineer Alex Cattelan:
“We don’t keep it at a fixed RPM, we have a window of operation that is optimized. We have been able to optimize the engine for a window of efficiency but it is still best to change your power and torque levels within that window as the customer torque request varies.”
“We don’t want to always be operating at one state because really you may be putting too much energy into the battery or drawing too much energy out of the battery. It is still good to vary that engine power and torque. Not to follow exactly what the accelerator pedal does, but to optimize efficiency.”
Finally Volt vehicle line director Tony Posawatz explains it this way:
“In charge sustaining or range extender mode, the Volt will not follow the throttle position. The challenge is to select the right operating points (RPMs) that are 1.) efficient, 2.) pleasing to the driver, and 3.) meet regulatory requirements.”
And he teases us, “we are about ready to expose people to this experience.”
This entry was posted on Monday, October 26th, 2009 at 6:10 am and is filed under Engineering, Generator. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
+3
Oct 26th, 2009 (6:21 am)Sounds like it’s time for Lyle to get another ride, better yet, drive.
Oh yeah, first!
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+23
Oct 26th, 2009 (6:21 am)Good morning. Lyle.
I like this new layout. This site is becoming so popular, it was difficult to find which comments I hadn’t already read.
This top down approach is best.
Thank you for making the change.
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Oct 26th, 2009 (6:22 am)Again, it sounds similar to cruise control. It will be interesting to see what customers prefer – rpm’s that follow their inputs or rpm’s the follow their load requirements.
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Oct 26th, 2009 (6:25 am)(click to show comment)
+7
Oct 26th, 2009 (6:31 am)Jason, #5. says,
As for the layout, I still prefer nested responses. Was there not a way for people to login and view first unread, as we do in the forums?
Jason, obviously your opinion is wrong. lol
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+6
Oct 26th, 2009 (6:32 am)I like the new format and I like GM’s approach.
I have been concerned in past threads that GM was trying to make the engine follow the pedal too much. This appears to not be the case based on the above notes and the Fox interview from the other day.
Maximizing efficiency is the only logical way to go with this. The engine should run at an RPM that is best for the battery and the overall efficiency. The ICE is thankfully not married to the accellerator pedal and is controlled by software logic.
The pedal will control how the electric motor responds (ie: how much power you send to the wheels) as it should.
Good Job GM. The Volt is sounding smarter all the time.
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+6
Oct 26th, 2009 (6:44 am)Hey GM, does the Volt use an Atkinson cycle engine?
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+2
Oct 26th, 2009 (6:58 am)Varying the engine speed through a few sweet spots based on electrical demand seems to me the most logical approach.
But I’ll bet that making that work properly was a real challange…..
If they are talking about it, it must mean they are very close to getting it right!
Now I want to know when I can see a Volt somewhere, and maybe get to sit in one!!! It has never been at the Cleveland Auto Show!
Maybe my paint color name will win!
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+4
Oct 26th, 2009 (7:01 am)Rashiid –> Right on, as usual
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+8
Oct 26th, 2009 (7:12 am)During the time we’ve been discussing this issue I’ve started paying more attention to what my Buick does. That’s not too easy because the engine is quiet compared to the ambient noise.
When one pays attention to engine rpm as judged by ear, in this car there is not too much of a relationship, because it decides to shift gears up and down for its own reasons so the engine speeds up and slows down without a tight relationship to the gas pedal position. But as it does so quietly you really don’t hear it at all unless you are listening for the change.
That is, I’ve decided that “driver expectation” as to the audible engine speeds may be exaggerated in our discussions. I can see that what has happened to me is that I’ve not been particularly aware of whatever relationship there is in my present traditional car.
So then I tried being aware in my truck, which is relatively speaking a noisy beast. What actually happens is that the engine speeds up wildly if one presses the accelerator, and then it slows down markedly as the truck goes faster. At steady speed, even pretty fast, engine rpm is usually low because the truck has a big engine and mostly drives without carrying much of a load. It’s easy enough to hear the engine and obviously what’s happening is related to downshifts on acceleration. What the truck does is more or less the reverse of what we have been saying drivers expect, yet it is what I’ve learned to expect and it seemed natural until I focused on it.
That’s all to say that I think the Volt will seem completely natural, whatever it does, after a week or two of driving. One’s mind accommodates.
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Oct 26th, 2009 (7:24 am)The high end of the Volt ICE operates at 4000 rpm. If NGMCO tests the new Cruze (1.4L) at Pike’s Peak they are sure to be operating at a much higher rpm. Fill the Volt 1.4L ICE with synthetic oil and you will have one happy engine. As far as noise goes. The loudest noise heard on the electric GEM I drive is the brake rotor shuush sound. With the Volt regen braking we may not hear much of this either.
=D~
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+3
Oct 26th, 2009 (7:40 am)I spoke with Volt Powertrain Engineer Alex Cattelan at VoltNation last year. I asked her if the Volt’s ICE would operate at a fixed rpm, or whether it would operate in a load following mode.
She indicated that the optimum was somewhere between the two. So the Volt’s engine would likely not change power output for small power requests from the driver, rather relying on the battery pack to make up the difference. However, if the power request was higher, or the battery drain exceeded a specifed limit, more power would be delivered from the engine.
Since this information is about 18 months old, things may have changed, however, it seems they want to find a methodology to provide average power.
From the GM powertrain website, the new 2.4L engine for the Equinox and LaCrosse produces ~120 hp at 4000 rpm.
http://www.gm.com/experience/technology/gmpowertrain/
The power curve appears to be pretty linear from 1000 to 4000 rpm. Note that 120 hp corresponds to 89.5 kW. By ratioing from 2.4L to 1.4L, the power output at 4000 rpm is 52 kW. At 1200 rpm, using the same math, the 1.4L appears to produce about 12 kW at 1200 rpm.
If GM uses a 10% battery buffer (1.6 kW), and you are in the city in traffic drawing 0.1 kW, the ICE might come on at 25% SOC and charge to 35% and shut off. The ICE would run for about 8 minutes.
For highway travel at 60 mph, drawing 12 kW (200 Wh/mile), the ICE would run continuously at the prescribed setting.
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Oct 26th, 2009 (7:41 am)Thank you GM and Lyle for the picture to study. Very exciting.
I like the stainless steel exhaust that will really last. Hopefully included in production.
Very impressive progress.
It really makes you wonder what all the other OEM’s are doing.
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Oct 26th, 2009 (7:47 am)This is excellent news! I hope there is some buffering built in so that temporary changes in demand (small hills, for example) are handled by battery to keep the generator in the most efficient mode longest.
Based on GM’s apparent design philosophy for this vehicle I suspect the actual RPM of both the motor and the generator will be absent in the gauge menu listings. This is a shame because it could help an efficiency minded individual to determine limits for most efficient operation.
I presume the Volt will have an OBDII port — I wonder what could be exposed to the driver via a ScanGauge? That instrument allows display of the engine RPM in a Prius…
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+2
Oct 26th, 2009 (8:10 am)This is true for people driving automagics…although I’m probably in the minority here, every car I’ve ever owned has been a stick shift, so engine speed by default, has a pretty close relationship to what my right foot is doing (unless there is a serious problem…). Its always a tad alarming to drive my dad’s truck or something and hear the engine doing all sorts of things I don’t think I’m telling it to do…but I’d probably get used to it eventually.
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+1
Oct 26th, 2009 (8:15 am)The real question is, will the efficiency gained by having the RPMs of the motor limited to one or more sweetspots be enough to overcome the loss of efficiency associated with not having the motor directly attached to the drive train.
I am very interested in seeing how this pans out in actual application.
Sincerely,
Dr. Ibringdoh
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+3
Oct 26th, 2009 (8:21 am)Thanks very much for ‘fixing’ the website, the nested comments meant I missed many of them. Now I can read them all. Lyle should put one of those polls to let the reader choose which format they like best.
Can’t wait to find out the actual MPG in charge sustaining mode. Especially on the highway at 65 mph because thats the only time I’d ever use it on out of town trips. Also be nice to know the MPG at 65mph with and without air conditioning. But I guess we’ll have to wait until someone on this board actually gets one of these cars late next year.
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Oct 26th, 2009 (8:27 am)And speaking of sweetspots with the ICE, I wonder if the car will tell the driver where the highway sweetspots are while driving. As this will vary based on weight in the car and HVAC requirements, it would be very nice to have the car tell you what the optimum highway speed is within the range you are willing to drive.
Some folks may be willing to drive 55-65, others may only be willing to drive 70-75. But I’d think within the range of speed you want to drive there must be a sweet spot for the ICE depending on current conditions.
This would be more useful than having an instantaneoues MPG as that sometimes is hard to judge as the grade of the road changes gradually.
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Oct 26th, 2009 (8:28 am)I agree I like the old layout. But it is not a big deal.
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Oct 26th, 2009 (8:39 am)Is it just me or is the site very slow now?
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+4
Oct 26th, 2009 (8:46 am)My Prius has continuously variable transmission (as do an increasing number of other cars), which means there’s very little connection between rpm and speed, or rpm and my foot. As my previous car was a stick shift, I expected to find this really disconcerting, but it never bothered me – and within a week I didn’t notice it at all.
I think in conventional cars, our brain incorporates the audio cues from the engine because they’re both prominent (loud) and relevant (tied to MPH) – but once they’re neither, the brain seems to learn to disregard them really fast.
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+1
Oct 26th, 2009 (8:51 am)In my mind, I have always felt there was two ways to approach the problem of ICE interaction.
#1. If the ICE is audible, or noticeable while starting, revving etc, then it rpm’s should follow the required load on the powertrain….or
#2. Sound proof the engine very well so it isn’t heard over a radio or the typical road noises.
It would appear that we are in the realm of #1. This is also how the 9 axle G.E. locomotives operate. They have a large ICE (diesel) which turns a generator. The generator supplies power to traction motors located between the wheels. The major difference being that the locomotives do not have batteries. In these locomotives, the engine rpm’s are wholly tied to the load required.
The volt’s battery allows the engine to operate in it’s optimum efficiency band. If GM is going to operate the engine in these bands, the rpm’s will not follow load exactly, but may calibrated to appear that it does. 1200 rpm is only 300-400 rpm above a typical engine idle speed. 4000 rpm is at the upper end of operation for most vehicles on the road. This is a rather large band of operation and the car will most likely behave like a regular ICE car with the exception of a rather high idle speed. If the engine is readily audible, I can see my self fighting the urge to “tap” the pedal while parked to get the engine to idle lower. (Those of us who have driven older vehicles know this technique well due to how the automatic chokes were setup)
All in all, I think the engineers will get it right. Personally, I hope they insulate the engine very well. I would rather not hear it at all.
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+3
Oct 26th, 2009 (9:04 am)I agree. I prefer the top down approach. And I really like the new quote feature.
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-3
Oct 26th, 2009 (9:13 am)I would like to know how much of a fuel savings there would be if the engine stayed at a low efficient sweet spot and a small transmission revved the generator higher and not a screaming 4,000 rpm’s.
A small diesel ICE has the torque to spin slow and up the rpm’s through a transmission. Yes diesel engines cost more but they last much, much longer. You can also make your on fuel at home for a diesel….
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Oct 26th, 2009 (9:18 am)It all depends on the ICE, GM has to tune the exhaust /intake manifolds, muffler, the cams and the timing to optimize the ICE for those sweet spots.. they probably just found out where the ICE needs to operate in the recent long distance testing so now they go back and tweak the ICE..
Most likely they calibrate their computer models and so the next generation of the Voltec will be improved without needing so much testing.
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-5
Oct 26th, 2009 (9:21 am)Dr. Ibringdo hits the nail on the head. In a direct comparison between a series hybrid (Volt) and a series /parallel hybrid ( Prius) this article gets the picture straight. The supposed sweet spot advantage of the series hybrid (Volt) just went away. The Volt engineers are programing an operating LINE not a sweet SPOT. The operating line is programmed along the peak efficiency points (min SFC) on the ICE engine map. They are doing EXACTLY what the Prius engineers did. Therefore the series (Volt) setup should suffer some penalty in MPG since instead of running the power directly to the rear wheels they are running it thru a generator/inverter/ motor. The only way they can beat or tie the Prius MPG in CS mode is to do it with things like drag coefficient and tire rolling resistence. I think the best we will see is the volt with an MPG that ties the Prius. That is if they were able to make that 1.4L into an Atlinson-Miller cycle which we don’t know yet. That may be some more disappointing news—-That the Atkinson cycle is for the next generation not first release.
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+3
Oct 26th, 2009 (9:24 am)It is nice to see these daily articles as we see the progress inching toward oil free mobility.
Based on what I know I’m still planning on second half 2012 purchase of a volt or BEV or whatever makes the most sense so I can drive oil free.
I sure hope GM will be far enough along in a year and has a plan to ramp up production a whole lot faster then they are talking about.
It is not hard to see scenarios with $300/barrel and $10/gallon gas, and I sure hope before that happens I have my electric mobility in place.
A peak oil article for those that like to read about that:
http://www.guardian.co.uk/business/2009/oct/26/oil-prices-production
Maybe as individuals we can prepare for the inevitable unaffordability of oil, since our governments are doing little about the problem (i.e. drill in Alaska, Nuclear, Wind, Geothermal and GRID investments, and we need to help our truckers probably with natural gas or something). The more we as individutals can do to reduce the demand for oil the longer we can put off the supply becoming insufficient.
But in the meantime I sit here and read daily as we crawl towards 10,000 cars a year whoopee!
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+6
Oct 26th, 2009 (9:34 am)Try driving any vehicle with the CVT Transmission…. and see how much engine noise there is…
On My 2010 Fusion Hybrid…. It took a week or so to adjust to the fact that when you accelerate heavily… the engine winds up quickly and (a bit loud in the cabin) and stays with a high RPM… You anticipate a transmission shift…. but there really isn’t one… As your speed goes up … the engine slows down till you reach the requested speed…
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+2
Oct 26th, 2009 (9:35 am)Lyle, can you ask if the engine is Atkinson Cycle? I would think GM wouldn’t mind telling us that.
If it is a fully optimized Atkinson Cycle, I would think it should be incredibly efficient.
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+4
Oct 26th, 2009 (9:36 am)Both of these are more cost and more complexity. I don’t consider 4000rpm to be ’screaming’ since there would not be a lot of accessories (a/c, p/s, etc.) to make racket. I expect that even at 4000rpm, which would only be required under high load, that the engine noise would be much less than road and wind noise. Not to mention stereo noise.
Remember, without direct connection to anything other than wires and motor mounts, this engine will be way quieter than direct drive to the wheels. It will probably have dampers other than just mount rubber as well.
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Oct 26th, 2009 (9:43 am)Matt: This is true for people driving automagics…although I’m probably in the minority here, every car I’ve ever owned has been a stick shift, so engine speed by default, has a pretty close relationship to what my right foot is doing (unless there is a serious problem…). Its always a tad alarming to drive my dad’s truck or something and hear the engine doing all sorts of things I don’t think I’m telling it to do…but I’d probably get used to it eventually.
———————
You will have lots of new things to get used to, since there will be no stick shift in the Volt. I think it will only have Park, Reverse, Neutral, and Drive. And I am not positive that Neutral will be there…..
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+1
Oct 26th, 2009 (9:46 am)I also like the new format – easier to check back and catch up on what you haven’t read.
From these comments and others, I’m sensing that GM is close to feeling comfortable with CS-mode – great news…
Off topic, but newsworthy from Automotive News:
Automotive News
October 26, 2009 – 12:01 am ET
WASHINGTON (Reuters) — U.S. Vice President Joe Biden plans on Tuesday to visit a closed General Motors plant in Wilmington, Del., for an announcement, according to the White House.
The visit to the Boxwood plant comes amid media reports that start-up firm Fisker Automotive Inc. is in talks to buy the plant to build plug-in electric hybrid cars.
The Wall Street Journal and the Detroit Free Press both reported on Friday that the talks for the purchase were at advanced stages and that an announcement was likely on Tuesday.
The White House statement announcing Biden’s visit said he planned a major announcement about the assembly plant’s future but gave no other details. Delaware is Biden’s home state.
The announcement is planned for 10 a.m. EDT on Tuesday.
Contact Automotive News
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+1
Oct 26th, 2009 (9:49 am)The only thing that would improve the new changes would be programming to allow the reader to follow a given thread.
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Oct 26th, 2009 (9:55 am)(click to show comment)
+2
Oct 26th, 2009 (10:00 am)I think that seeings how people will be driving the engine in All Electric mode anyway most of the time where there is no engine pitch change anyway, it shouldn’t be weird to people when when the engine comes on and does not change pitch either.
At freeway speeds, when almost all RE mode will take place, the road noise and air resistance will mask the engine completely I’m guessing since its so well sound insulated.
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+6
Oct 26th, 2009 (10:07 am)I agree. The quoting mechanism is adequate for carrying on sub-discussion as needed, but the overall layout will be a big time saver. Thanks, Lyle, and +1 to Rashiid.
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+7
Oct 26th, 2009 (10:11 am)You’re talking probably saving 10-20 gallons of gas a year which is way cheaper and faster than paying for an entirely new engine to be engineered, then get parts suppliers to make it, then get a GM factory converted to assemble it, then work the bugs out of it, then train GM mechanics to fix it, write repair manuals for it. etc. etc. All of that costs GM money.
For example, if you drive 200 miles a month on range extended mode, you are only saving 1 gallon of gas a month going from 40mpg to 50 mpg. I doubt they would even see that much benefit, it would probably be more like a 5 mpg improvement.
That’s the kind of bean counting GM NEEDS to do. This way there is mass parts production because it shares parts with the Cruze so replacement parts will be cheap, easy to find, etc.
GM needs to put their money into building a DI HCCI engine. I’m sure we’ll see it in a future Volt/Cruze iteration. Until then, I think this engine is great.
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+4
Oct 26th, 2009 (10:12 am)Dan, actually, if I ‘m not mistaken, that photo dates way back to the proof of concept days before they built the Mali-volt mules. I’m pretty sure it’s not relevant any more, other than as a curiosity and conversation piece.
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Oct 26th, 2009 (10:13 am)For me, it has never been the fastest site to begin with.
I don’t notice a difference in speed now, though.
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Oct 26th, 2009 (10:14 am)Totally agree with you. I have an Altima with CVT transmission. At first, it was disconcerting to see the RPM go down while speed was going up during acceleration. Now, to me, it’s just the way the car runs.
Same thing must be expected from the EREV. At first, it might be a tad strange but we’ll get used to it, especially if GM did a good job at insulating noise. Which they must have done.
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+1
Oct 26th, 2009 (10:19 am)I think it might just be you; things are zipping along fine, from my location.
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Oct 26th, 2009 (10:28 am)Amen!
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Oct 26th, 2009 (10:31 am)Dr. D.:
Excellent report! Thank you. And what a great photo.
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Oct 26th, 2009 (11:02 am)Lyle:
When you get there for your test drive, ask them one more time about the “choices of colors” again.
Fleet Sales of the VOLT will be especially important to get the VOLT ‘profitable’ – especially if the price-tag-vs-MPG issue really does have an effect on retail sales.
And almost all Fleet Vehicle sales are in White or Red (outside of rental car companies). Could you ask them again why they would ignore the need for these colors?!
Thanks.
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Oct 26th, 2009 (11:04 am)Cool — I can’t wait to see the whole system working at my local Chevy dealer!
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Oct 26th, 2009 (11:11 am)CVT Transmissions have their drawbacks too. My wife is currently driving an Altima SL, and she does enjoy driving it ‘briskly’. The downside of CVT is NO engine braking… ever. We had to replace the brake pads at 9000 miles on the odo. Now it’s coming up on 16000 miles and it is starting to signs of needing them again. I’m not sure I like the added maintenance.
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Oct 26th, 2009 (11:15 am)But if you put CVT in terms of the volt then your drawback is not an issue as the VOLT has regen braking and willl act like the engine braking from a non CVT vehicle.
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+5
Oct 26th, 2009 (11:16 am)Lyle,
I have to agree with others who like the change to this “new” format. One reason I have stayed off the forum lately is that it was becoming too difficult to find comments that were new to the subject with out scanning through the whole series of comments. I just don’t have that much time to devote to that type of searching. Thanks for making the change. I liked the ability of replying to a comment, but it was over-used by most people who were making “replies” to a comment that had absolutely nothing to do with the original comment. Let’s see how this change works. Thanks, again.
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Oct 26th, 2009 (11:18 am)I thought this had been discussed and dealt with several times. The answer is: “Not yet”.
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+1
Oct 26th, 2009 (11:35 am)Lyle,
I find the “(Quote)” option handy compared to what we used to do to “copy” someone’s comment or part of to enable us to reply to it. One thought came to my mind. Is it possible to keep a counter next to the “(Quote)” string to indicate how many times someone has responded to it by clicking on the (Quote) text? Or just indicate in some manner that at least one person has responded to the comment.
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Oct 26th, 2009 (11:43 am)I think the best place for a CVT is in the Genset.
JMHO
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Oct 26th, 2009 (11:44 am)If I had to replace my pads every 9000 miles, I’d be positively *livid* about it. To put it mildly, thou art a patient customer, CG.
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Oct 26th, 2009 (11:54 am)My guess is that is why Posawatz is claiming some pretty poor generator mode mileage figures. They’re not using a Atkinson-Miller engine cycle yet.
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Oct 26th, 2009 (11:56 am)Jim I, We’ve all learned a lot by being here reading GM-Volt. Thanks Lyle!! & (PRNDL) & LJGTVWOTR.
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Oct 26th, 2009 (12:12 pm)A conundrum? A Twilight Zone analogy?
I believe if the software were to follow a unique thread, the reader would skip amongst comments that are seperated by long periods of time. Once the reader finished that thread, the original nested link problem would appear. Does the reader now go back to the top to read all the comments, rereading the ones of the just finished specific thread again?
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Oct 26th, 2009 (12:40 pm)No atkinson cycle would kill the CS mileage.. and it is supposedly easy to implement.. The 1.4l engine making 70hp strongly suggests an atkinson cycle.
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+1
Oct 26th, 2009 (12:52 pm)Herm,
What is your source on 70 hp from the engine? Isn’t it the generator that’s rated at 53kw (71 hp)?
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+1
Oct 26th, 2009 (1:13 pm)Here we are talking about cs mileage again.
imho, as long as the combined (EPA sticker) mileage is around 100mpg as hinted before, there is no issue. Most people don’t care about actual mileage, can’t calculate their actual mileage and even lie about it if asked.
At current E85 prices, the difference between 30mpg and 50mpg for an average driver (12k miles per year) is only about 30 bucks per month. Nobody buying a 40k car cares about $30. I sure as heck don’t.
Now back to the topic of this thread. I can’t see where the rpms vs the driver input will have any impact on the people buying Volts. As long as GM makes it quiet enough (and we already know that they can do that) it’s a non-issue.
I will report back on these issues (noise and mileage) when I get my Volt and have about 6k miles on her. If I empty the tank in 6k miles, I will be very surprised. Let’s see… that’s about a THOUSAND mpg.
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Oct 26th, 2009 (1:19 pm)Apparently there will be D and also L (of PRNDL), with L the choice when one wants to have heavy regenerative braking, in effect allowing you to speed up and slow down in city traffic without moving your foot away from the accelerator.
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Oct 26th, 2009 (1:22 pm)And he teases us, “we are about ready to expose people to this experience.”
We are ready to be exposed
I don’t think he means exactly what his words say, but we get the idea and like it.
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Oct 26th, 2009 (1:29 pm)It seems that people are making to big a deal about the mileage in cs mode. If the mileage in cs mode is only 40mpg instead of 50mpg, what is the actual effect (beside marketing).
For me, it might mean an extra $45 per year in gas costs (assuming 15,000 miles per year, 3,000 miles in cs mode and gas at $3 per gallon). Not a big price. the higher the MPG figure, the less important it is. The difference between 80mpg and 90 mpg would be insignificant to most car buyers.
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Oct 26th, 2009 (2:04 pm)LIke the new format, but harder to bait trolls…
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+1
Oct 26th, 2009 (2:04 pm)Pure cs mode is never achieved for most people. I think the Volt will have very high AVERAGE mileage since it goes 40 miles on battery vs 12.5 on the plug-in Prius.
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-1
Oct 26th, 2009 (2:27 pm)The new format is easier to follow but for the West Coast that much more buried. Anyways. Aside from mandatory ICE design priorities like reliability and safety from principal market factors one could make a strong argument range to be a super priority. That’s my point: Taking all factors outside of mandatory priorities and then pulling all stops (using turbo or whatever), what range is possible?
For those enamored with Atklinson-Miller – please note a whole lot of such thermodynamic cycles. True, a number of hybrids (including GMC’s Tahoe) apply an Atklinson cycle labelled thermaldynamic process. (But NOT the original patented 19c. single crankshaft turn Atlinson-cycle.) Google “Atklinson-Miller” [see Wikipedia] See also http://www.asmeconferences.org/ICEF09/ViewAcceptedAbstracts.cfm
ICE simulation is itself an engineering field.
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Oct 26th, 2009 (2:29 pm)We have a car here which gets 230 equivilent MPG but costs $40k. I don’t think adding cost to save fuel would be a good move.
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Oct 26th, 2009 (2:53 pm)That’s a refinement for the Cadillac version which I wish GM would follow with soon.
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Oct 26th, 2009 (3:05 pm)Cool. I can quote my own comment. Hope this table doesn’t get all funky.
Some calculations for my 42 mile commute:
Volt Prius
electric mode 40 12.5
cs mode 2 29.5
cs mode mpg 30 50
gallons used 0.066 0.59
average mpg 636 71
cost @$3 20cents $1.77
CS mode mileage just doesn’t matter. These are both basically commuter cars with highway capability.
If you want a Volt/Prius non-statistic, it costs almost 9 times a much for gasoline for the Prius. (In my narrow and biased example)
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Oct 26th, 2009 (3:08 pm)AHAHAHAHAHAAA!!!!
A trolling we will go…..
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+1
Oct 26th, 2009 (3:09 pm)#65 Tom Harwick:
Nice to see somebody use their actual name, LOL. Assuming that it is, of course.
As to 4000 rpm, I don’t consider that to be “screaming” in this day and age. We’re talking about a 1.4L, double overhead camshaft, 4 valve per cylinger engine. If is was any kind of a sporty Honda, the red line would probably be about 9000 rpm. That’s screaming. 7000 is revving pretty hard in my book. 4000 is just a bit above high idle. As many have said, with modern sound control technology, I don’t expect to hear it.
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Oct 26th, 2009 (3:14 pm)RB: Says:”Apparently there will be D and also L (of PRNDL), with L the choice when one wants to have heavy regenerative braking, in effect allowing you to speed up and slow down in city traffic without moving your foot away from the accelerator.”
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I found this on a US News site article about a Volt test drive:
“A large shifter is present, but is recessed into the center stack when the car is parked — and because of the Volt’s unique powertrain, its only settings are forward, reverse, and low.”
So I guess there is a possibility that there is no “Neutral”, which means we have P-R-D-L.
Lyle – You have seen this up close. Can you give us a first person answer about the shifter?
Thanks.
Jim
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+1
Oct 26th, 2009 (3:15 pm)That’s a GOOD thing, hopefully they’ll just stay away.
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Oct 26th, 2009 (3:20 pm)While yes, that is true, I was only focusing on the exhaust system at the lower center, (stainless-reflective pipe).
The idea was I am impressed with the quality of stainless steel usage, in that the ER engine will be subjected to more unpredictable run-times, and thus, a higher possibility clearly that the exhaust system may not be able to build up enough heat to evaporate and expell built up water, especially up North.
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Oct 26th, 2009 (3:23 pm)Mike-o-Matic #71: “That’s a GOOD thing, hopefully they’ll just stay away”
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Good luck with that one….
It seems that when the temperature changes, and the sun heats up the rocks they are living under, they come out to post on our happy site…… Or, God forbid anyone here says ANYTHING they consider to be bad about their beloved Toyota P-Mobile, then look out for the wild eyed rants about how the Volt will NEVER live up to their car!!!!
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+1
Oct 26th, 2009 (3:27 pm)Another positive vote from me for the new format Lyle…
Just FYI…the picture with this item is indeed from way back – I remember when I first saw it commenting on how the heck they planned on fitting that monster inside the mid-sized concept (typical smarta$$ comment from me)
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Oct 26th, 2009 (3:35 pm)I think for many of us if the Volt got 45mpg we’d be fine because WE know the best feature is the 40 AER. For the Pat Q Pubic, they’ll scream foul.
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Oct 26th, 2009 (3:40 pm)I wonder if you can quote somebody quoting someone?
Hmmm…..
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-12
Oct 26th, 2009 (3:42 pm)(click to show comment)
Oct 26th, 2009 (3:42 pm)-2
Oct 26th, 2009 (3:50 pm)Thanks for the negative votes. Sorry for thinking and expanding the mind.
Yeah, no way anyone would want an engine that’s lasts for 300K miles and can run on peanut oil. What was I thinking….
Hey Lyle think many on here can understand the “SNAP 25″ Process.
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Oct 26th, 2009 (3:58 pm)I think GM realized it was a mistake to announce the MPG. It’s obvious by the severe lack of any follow up.
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Oct 26th, 2009 (4:15 pm)This is my Non gearhead opinion. If the 1.4L ICE can’t spit out 71HP (53KW) on average, there’s something wrong. A Suzuki GSX-R 750 (750cc) can spit out 141.00 HP (102.9 kW)) @ 12500 RPM and if you tune it down to half its, ~70.5HP @ 6250rpm. Sure that’s a buzz but it’s also got a much better power to weight ratio. That 1.4L better be able to push 71HP (53KW) with no problem.
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Oct 26th, 2009 (4:17 pm)Hopefully GM will allow a user to select different modes of engine-generator behavior. I would like a mode that recorded in (aprox.) 1 minute increments of load, and calculate the average then step up ,or down to fixed draw from controller, or BUS? and fixed RPM from engine-generator. Different modes would be 1 more
reasons to get a Volt (maybe a lower priced future generation):
- Insurance from peak oil, & high prices
- Reduce, or eliminate dependence on foreign oil
- Ability create your own fuel at home(PV cells, & wind) to power the vehicle, & home
- Clean air, and reduce impact on environment
- Fun high torque driving, especially around town
- Silent
- Propulsion system configurations easily applied (fwd, rwd, awd, genset, or battery front, back, mid, sideways, etc.), & will allow for unique body styles.
- Technology advances easily applied [battery chemistry (cells), & pack electronics, gensets, electronics (controllers, inverters, charger (& ports), interface), & programming].
- Dependability (battery, & genset) to point A & B
- Long lasting electrical components (hopefully battery cells also)
- Conventional car built-in: Convenience in necessity, or emergency (don’t have to charge complete, or at all), & unlimited driving.
- Ability to select and use lowest cost energy if one happens to rise (in my area E85 stayed around $2.15 summer of 2008 while “regular” gas was $4.30 +).
- Efficiency of the VOLTEC system
- New tech
Add to the list if I missed any!
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+4
Oct 26th, 2009 (4:17 pm)Lyle, for the record on this new format, me likes!!!
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+1
Oct 26th, 2009 (4:33 pm)That’s all we need, LOL. “D” for “Drag”, “L” for “Lunge”, and “R” for “Race”. Next case.
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+1
Oct 26th, 2009 (4:38 pm)Noel – What about “P” for Prepare For Takeoff?”
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Oct 26th, 2009 (4:48 pm)Unlike in a ICE powered car, there will be no idle for an Electric Car. Thus no need to “turn over” the car and have the some restraint engaged. Maybe the function will be tied to booting-up the car? Press Go, Press Gas –> Forward motion. No need to shift into gear.
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+1
Oct 26th, 2009 (4:56 pm)Creating different generator modes should be relatively easy, but there is increased risk involved.
For a “feature” that is used rarely (less than 25% of typical driving for an ideal VOLT customer should be under CS) and when even when under CS, most of the miles, e.g. constant speed travel with variations in road grade less than +/- 2%, would have no benifit from this feature… Furthermore, its hard to see how a consumer would benifit consistently from choosing thier own mode. Each mode would have pluses and minuses and relying on an end user to choose when each different generator mode should be used seems dicey under warranty
GM should just focus on delivering one mode that is the most efficient in thier testing for the first run-through. Maybe if there is sufficient evidence that different modes are substaintly more efficient under certain conditions, the feature can be brought on for Volt 2.0.
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Oct 26th, 2009 (5:05 pm)Errr… I don’t want one in the Volt. Following a 75%/25% split for CD/CS milage, even a palty gas engine durable for 150,000 miles results in 600,000 total car mileage. IE needing to replace the battery a good 2-3 times, I doubt I’d mind the 1-2k to replace the engine in comparison to paying the 1-2k up front to ensure the engine lasted even longer.
And its fun to run of Peanut Oil. But the Volt’s generator is capable of E85. If it gets even 30 MPG on E85, I’d be hard pressed to use more than 20 gallons of Gasoline in a year. Since running on B100 is rarely supported from the factory in most automobiles these days, at best your looking at B20 under warranty.
Not sure if voiding my warranty is worth saving a few hundred gallons of gas to go to B100.
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+1
Oct 26th, 2009 (5:33 pm)Come on , You know better , Dont try to show everybody your intelligence .
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Oct 26th, 2009 (5:35 pm)Jim I:
Works for me!
BTW, LJGTVWOTR!!
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Oct 26th, 2009 (5:37 pm)“Each mode would have pluses and minuses and relying on an end user to choose when each different generator mode should be used seems dicey under warranty.”
Steel, I agree, especially for the 1st generation
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+2
Oct 26th, 2009 (5:38 pm)#87 steel:
Amen brother. KISS
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+3
Oct 26th, 2009 (5:41 pm)I don’t see how this kind of comment does anything to raise the level here. Spare me.
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+2
Oct 26th, 2009 (6:04 pm)If the generator is rated at 71hp why would you need an ice stronger than that?
Thus we guess the ice in the Volt will also do 71hp, maybe a little bit more to account for losses.
The regular non-turbo 1.4l ice as used in the Cruze is rated for 104hp.. we know from the example of the Escape and Prius that when you atkinsonize an ICE it losses about 25% power but gains efficiency.. so from these hints we guess the Volt also has an atkinson ice.
GM already uses an atkinson cycle in the 2-mode hybrids so they know how to do it. Pretty much all it takes is a modified camshaft.
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+1
Oct 26th, 2009 (6:36 pm)That sounds right. It’s probably closer to 80HP out due to conversion loss.
Remember, when it comes to ANY electrical conversion, it is almost never more than 95% – 96% efficient and in the Volt for every conversion from (Genset) AC to DC to AC again there’s a cascade of losses.
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+2
Oct 26th, 2009 (6:52 pm)Sounds like GM has thought out the engine well. The design will have sweet spots for the perfect computer controlled operation. The Volt is sounding more like a high tech fighter jet than any other car. It will be amazing to own and drive one at any price. Everyone wants a test drive.
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Oct 26th, 2009 (6:55 pm)CaptJackSparrow
I hear what you say but I don’t the losses will be significant. Will the gen-engine be aircooled ?
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Oct 26th, 2009 (6:58 pm)For those talking CVT, the best place for the CVT is on the Genset. Make the ICE run at it’s very sweetest spot for efficiency and HP. This should be a point where 53KW is best attained. Then couple a tuned CVT to adjust output RPM for best output per power requirements. The CVT will all be automatic and the ICE will run at its ideal narrow rpm band (+- 400rpm) sweet spot, not “a few RPM ranges”. This eliminates computer control of RPM range and the best part is it’s KISS.
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Oct 26th, 2009 (7:01 pm)As far as I know it’s liquid cooled. The ICE that is. The losses will be ~4% but it just depends on how long the cascade is. We only know of a few and I didn’t include control electronics and monitors. It’s a good enough SWAG though.
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Oct 26th, 2009 (7:20 pm)+17. Is that a new recored?
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Oct 26th, 2009 (7:26 pm)Hey guys, we replace the (drum) brake linings in our vintage racing Corvettes every 50 miles sometimes. And it has plenty of engine braking, what with the VERY light flywheel and all. Don’t feel bad.
CorvetteGuy:
You could think about taking your wife’s shoes down to the shoe repair man and have him take a couple of those lead insoles out while she’s not looking, LOL.
She sounds like my kinda woman, actually. Maybe you should just count yourself lucky. Brake pads are cheap, hehehe.
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Oct 26th, 2009 (7:28 pm)Herm @ 94,
I’m accounting for more generator efficiency losses than you are ( I’d allow for 15% or more when it’s running hard (admittedly big unknown here)). Also, you don’t want the ICE running at peak output (and likely you’re not getting that at just 4,000 rpm) to get the 71hp out of the generator.
I figured 100hp max out of the engine was a good match for wanting to be able to sustain 70 hp out of the generator.
/ A lot of this is dependent on 2 things:
1. Efficiency losses
2. Size of battery “buffer zone”.
// If GM was, in fact, able to get an atkinson cycle to work in this equation, then my mpg prediction would have to be kicked up to 35 to 40 mpg. I’m sticking with 30 to 35 mpg.
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Oct 26th, 2009 (8:30 pm)Perhaps its not an atkinson, the 1.4l is derated to 4000 rpm and that works out to about 70hp output from its normal 104hp at a higher rpm.. if its not an atkinson it will really kill the CS mileage.
It would be nice if Lyle could pin down a Volt engineer and get a definitive answer.
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Oct 26th, 2009 (9:01 pm)I will be impressed if a Volt driver can’t hear a 4000-RPM engine a couple feet in front of them. I’m not really up on sound suppression in cars, but I’ve never been in a car where 4000 RPM is nigh-unnoticeable. “High idle” in my car is maybe 1500 RPM tops (I’ll have to check now that you mention it). 4000 RPM is towards the top of what I hit accelerating in a given gear in a stick shift, unless I’m really hauling. It’s not an exceptionally high RPM, but personally I’d say it sounds pretty “prominent.” I’m not saying it will necessarily be a huge problem (especially since the engine is more likely to be at this state when you’re putting the pedal to the metal anyways), but it could be an adjustment for some.
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Oct 26th, 2009 (9:05 pm)Thanks, Dave G. At least we’ll get the answer in one year one way or other.
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Oct 26th, 2009 (9:17 pm)I believe the 42 mpg (highway) ICE number is correct. Possibly higher for right lane cruisers.
My 600cc street bike is sold with a California air box to meet emission standards. Needless to say, it’s easily changed to the 50 state K&N air box . Will the California model Volt have a smothered “pollution control” ICE? Will the Volt require California SMOG certification? Is there a switch to run in ICE mode regardless of battery level?
=D~
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Oct 26th, 2009 (9:23 pm)http://www.hybridcars.com/news/fisker-build-plug-hybrids-former-gm-plant-26195.html
Take Care
Arch
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Oct 26th, 2009 (9:41 pm)Remember it will only hit 4000 rpm when you cruising at 100mph (or going uphill with a full load), wind and tire noise will drown it out.. its not like an ICE car that you have to rev up to get good acceleration.. the acceleration power needs of the Volt are met by the buffer of the battery.. the ICE may be loping along at 2000 rpm and meanwhile you got the throttle floored while you merge into a hwy.
I think it will be a rare occasion that you will notice the genset running.
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Oct 26th, 2009 (9:56 pm)Expect about 95% efficiency on the generator, Honda got their motor/generator up to 97.5%
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+1
Oct 26th, 2009 (10:14 pm)We got an excellent interview by Maximum Bob at:
http://gm-volt.com/forum/showthread.php?t=3583
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Oct 26th, 2009 (10:35 pm)Bob’s apparently talking about 40 to 50 mpg.
/That would take the volt out of “it’s an issue” territory and put it firmly in “good enough” as far as RE mpg is concerned.
//I’ll still have to see an independent test to concede, though.
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+2
Oct 26th, 2009 (10:48 pm)“We don’t want to always be operating at one state because really you may be putting too much energy into the battery or drawing too much energy out of the battery. It is still good to vary that engine power and torque. Not to follow exactly what the accelerator pedal does, but to optimize efficiency.”
Wondering if one state is very efficient compared to multiple points , then why not to use a Ultra capacitor instead of battery and make a range extender only car. or even put an ultra capacitor before the battery so that you don’t take more cycles from the the battery
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Oct 26th, 2009 (11:05 pm)I like the new format – the only thing I would recommend is figuring out a way to reduce the space between each comment box. There is a lot of dead space that can be reclaimed and make the page not so long.
That said, hopefully GM unveils CS mode at the LA auto show in early December. That gives them 11 months to work out the bugs!
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Oct 26th, 2009 (11:06 pm)Note that it is based on the EPA Hwy test.. God knows what it will do under real conditions.. this is a BEV and it will act totally different from an ICE or even a Prius. Hypermiling techniques will not work on a BEV.
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Oct 27th, 2009 (5:57 am)Gotta be, my friend.
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Oct 27th, 2009 (6:55 am)Exactly
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Oct 27th, 2009 (6:58 am)I wouldn’t concede based on some numbers thrown out by Lutz in an interview but logic and known specs should have convinced you long ago.
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Oct 27th, 2009 (11:00 am)I hope the IC engine is so quiet you barely realize it is running … even at full throttle. Low vibration and quiet is definitely what I’m hoping to see.
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Oct 27th, 2009 (5:43 pm)+22 now. Stretching out the lead!
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Oct 28th, 2009 (12:00 pm)Just to make sure I understand what you’re saying: You’re suggesting that if GM calibrates the manifold, exhaust, valves, and timings for the RPMs that the engine utilizes in real use, this will be enough to overcome 2nd Law issues incurred when the motor is not engaged to the drive train?
Respectfully,
Dr. Ibringdoh
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Oct 28th, 2009 (12:05 pm)Another way of looking at this problem:
What would be the fuel efficiency of this same 1.4 litre engine if it were deployed using Toyota’s drive chasis?
Also, what is going to happen to the fuel efficiency when a person is carrying passengers plus luggage, heading up an interstate incline at 60 miles an hour, and has to step on the throttle to pass a truck? Will there not be an even greater loss of efficiency from not having the motor directly connected to the chasis?
Respectfully,
Dr. Ibringdoh
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Oct 28th, 2009 (5:12 pm)Dr IBringdoh,
Your answer to whether the Volt 1.4 liter normally aspirated engine is running Atkinson cycle is a question so far un-explicitly answered by GM. But any competent Sherlock Holmes can deduce whether it is so or not.
The published ratings for the normally aspirated Family 0 1.4 liter, VVT, DOHC, engine was 90hp or 66Kw @ 5600 rpm and 125 N-m of torque at 4000 rpm in 2003. A later version, in 2006, is rated at 100 hp or 75 kw. Neither version is DI; the first SPI, the second improved to MPI.
The Cruze 1.4 l Family 0 engine built in America is a VVT, DI, turbo version, same bore and stroke but rated at 140 hp. Presumably the VOLT engine will be manufactured on that same Flint engine line. Presumably it also will be DI but normal aspirated. That usually means it Hp would increase to perhaps 104-110 Hp.
The published Hp requirements for the Volt are that it must be sufficient to power a 53 Kw or 71 hp electrical generator at 4000 rpm.
Opel Amptera however publishes the specification of the engine in the engine generator of the Amptera supposedly an identical Voltec drive European version of the VOLT as 1.4 liter Family 0 normally aspirated engine @ 82 HP.
Taking an engine rated @ either 100 Hp, or in older form 90 Hp, and only obtaining 82 hp from it, means it has been detuned. How & Why? Well it is well known that running Atkinson cycle, the thermal efficiency goes up, but the Hp produced goes down.
Given that you can control the valves such as by VVT, which the 1.4 l already has, the only change to create Atkinson cycle is a revised cam, and altered software in the ECU. Probably a two day job for an engineer, or a backyard mechanic.
Therefore Sherlock Holmes deduces that the VOLT engine is running on Atkinson cycle — just like the 28% larger displacement Prius engine.
QED.
PS Wikipedia says that GM has demonstrated the same 1.4 l, Family 0 , VVT, DI engine with some modifications such as cylinder sensors for the Demonstration engine for running HCCI mode. The engine was modified to have turbo assist and simple VVL, along with an alternate ECU and the already mentioined cyclinder senors. The HCCI engineer at the Demonstration said that the HCCI engine is particularly useful for applications like an engine generator in a Voltec powertrain and saves significant amounts of fuel, making it the the equal of a diesel, but much lighter and cleaner.
Which is neither here nor there. Apropos of nothing, but potentially significant.
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Oct 30th, 2009 (8:58 pm)Well I hope you’re right. It’s a good point that the battery serves as a buffer for hard acceleration. Just to be difficult, I will point out that in my personal experience, going fast enough on the highway for the engine to hit 4000 RPM results in some significant engine noise that is not drowned out by the road. But cars are all different, and the Volt will be more different than most! Hopefully that translates to quieter.
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