CleanMPG Reviews the 2011 Chevrolet VOLT - Review Blog

Discussion in 'In the News' started by xcel, Jun 10, 2011.

  1. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Interesting. I've never driven a vehicle that a spring loaded stalk set up so that you could cancel high beams by pushing it forward yet again -- I've always had to pull it back manually.

    A 20% change is actually not as much variation as I expected... though (since I'm in MN) I do regard high 20's as "warm." ;)

    The AC hit jives with what I've seen in other vehicles -- and if the system comes on to cool the pack I guess there wouldn't be any point to sweating in the cab while it's on (since the energy is already being used), eh?
  2. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Hi AnotherVoltOwner:

    Let me reiterate what Sean said about having you here. You do not know how much I appreciate your knowledge and understanding of the Volt’s inner workings. And the specific details you have brought to the discussion are especially welcome!
    When driving an ICE based car, we usually think in terms of the partial load BMEP because running an engine at higher RPM’s with the throttle plate wide open to remove most of the pumping losses incurs undue frictional losses (due to the higher RPMs) resulting in lower overall fuel economy.

    With the Volt’s 1.4L spinning up at 99% LOAD at the various RPM’s for most of the time it is running just proves there can be a controlled solution with MG1 shunting everything extra it can back to the pack while still controlling RPM to keep the engine from running away. With my limited time behind the wheel under CS mode, I only remember seeing one instance between a 1900/1,800 RPM to 1500/1,400 RPM transition where the 1.4L dropped back to 80% for just a few seconds. With that, a BSFC map would suffice perfectly.

    With the Volt at close to WOT in Closed Loop at any number of RPM ranges, the resultant FE appears to work exceptionally well while generating the optimal HP for a given amount of fuel with enough power to drive the car per demand and in whatever conditions while shunting the excess back to the pack for pure EV just minutes later. We experienced a similar situation in the 11 Sonata Hybrid just after New Years when I recorded the “P&G’ing the Li-PO” video. In colder temps, the ICE was running about 97 to 98% LOAD giving the car all it wanted while shunting the excess back to the pack for EV down the highway just minutes later. In warmer weather, it was more like 92 to 93% while doing the same.

    In the case of everything but the Volt, I have never driven a vehicle running at 99% LOAD while accelerating and received better FE from it than when running at a lower partial load is all. The Volt with its mostly electric drivetrain control (MG1 again) appears to have overcome that as the MM 35 mile drive results attest.

    Overall, a good thing from our perspective because of increased thermodynamic efficiency which improves fuel economy but that high load had to be wreaking havoc on the engineers who were responsible for the Volt’s NVH. I would have loved to be sitting in on one of the high level engineering discussions that had to be going on back in the summer or fall of 2008 when the efficiency guys and the platform guys were hammering out the details about this exact discussion over any number of very long meetings.
    This is the kind of detail that is so good I am almost beside myself! Ewanick and I had a short discussion about the Volt, its RPM ranges, MM and even maximum ranges during the LA Auto Show Press Event late last year. The only real bit of meat provided was how nobody will ever match his EV range distance after a full charge and MM top off at 94 miles. Which means after a full 13 + kWh charge, running MM as soon as you leave the drive is probably allowing an unhealthy expansion of the packs useable SoC on the upper end. I would like to know the standard SoC range from MT to full and what may be available on top to further exploit in case you had to.

    I ran out of time while trying to take some better pics with a trip to the local US Post Office, the local movie theater and an empty lot within my subdivision just 45-minutes prior to the car being picked up. It was overcast, some fog and the sun was peaking through. A terrible morning for pics and there was little I could do about it :(

    2011 Chevrolet Volt

    From the Post office to the movie theater, somebody was having fun with this little beaut ;)

  3. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Hi AnotherVoltOwner:

    And thanks for the push forward and push forward again for highs to low beams without inducing the double horn beep.

  4. Chuck

    Chuck just the messenger

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    At least former Congressman Anthony Weiner has some sense of when to stop once credibility is zero. Instead, you keep going on and it's become comical - just like if Mr Weiner refused to step down.

    Maybe the internet has gotten in the way of your good sense - in-person do you call someone out as an IDIOT and expect a group of strangers to believe you? Any self-respecting salesman, PR guy, etc. is going to start out respecting the other view point before they start to differ.

    Compound to that, I along with others here have known that "idiot" Wayne for years - what makes you think a stranger popping out of the internet cloud has better judgement on one's character?

    Chances are you would not behave this way in-person - most people know better than to epically make a fool of one's self. Anyway, you look so silly you push people towards Wayne's opinion.

    Your presentation is too personal to make sense, so I wonder about people like you - why you do it? Pretty sad you want attention this bad.
  5. MaxxMPG

    MaxxMPG Hasta Lavista AAA-Vee Von't Be Bach

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Apparently the newbie felt that Wayne was "not respecting the package", as in sound insulation package.

    If Wayne was answering a question and someone threw a pie, would he spend ten minutes addressing the pie? Oh wait, that hypothesis has been exhausted already.

    Personally, I'd like to see the energy spent in those newbie posts, as erratic and misdirected as it may be, directed at Repsumer Conorts because of that publication's questionable and unique brand of automotive reviews. Their reliability data are gathered only from their subscribers, so their little red and black circles are about as meaningful as a beauty contest held within the walls of the Branch Dividian compound. There's a whole world of people, and billions of miles driven, that the little boiler room facility will never know about. A year's subscription to this closed society? Now there's a package I could never respect.
  6. diamondlarry

    diamondlarry Super MPG Man/god :D

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    My take on the whole controversy of the annoying noobie is this: If he had any idea whatsoever of how passionate Wayne is about clean emissions, high FE and the resulting lowering of our dependence of foreign oil, he would probably realize, as I have, that it is probably difficult for Wayne to say anything disparaging about an awesome machine like the Volt?
  7. herm

    herm Well-Known Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    MM is a late addition to the Volt, to counteract going into a low power event while in a prolonged run up a mountain.. as such the Volt wont allow you to use it if the battery still has a charge in it.. I think.
  8. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Super Moderator Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    The manual, apparently, says they you select it at the beginning of a trip.

    It's mentioned in this forum post ( an owner mentions that after selecting MM in the driveway they immediately saw their EV range drop as the car adjusted to the new 45% limit.

    VOLTEREV New Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    I personally think Wayne is doing a great job! I wish I can drive my Volt like he did to get the most of my electrical range, but in New York I would get eaten alive :). Any suggestions on maximizing mileage driving somewhat normal?
  10. southerncannuck

    southerncannuck Well-Known Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Re adjust your mirrors so that you don't them.
  11. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Super Moderator Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    I believe for CD it boils down to a few things:
    - Accelerate as slowly as possible
    - N-glides where possible (downhills and when you need to slow down)
    - Minimize the additional draws: A/C, stereo
    - Take it easy

    Plus of course there's always the usual hypermiling techniques of anticipatiory driving with DWB, light timing and smart braking to reduce braking and therefore reduce motor/engine use.

    Maybe we need an ePrimer, but in the meantime, if you haven't already done so, please read the CleanMPG Primer, which will take you to a lot of useful information.
  12. Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    As an aside, I think it's interesting that so much time is spent discussing the CS mode of the Volt. The point of the car is supposed to be that CS is the exceptional condition. I average 95%+ EV operation. Everyone, GM engineering included, understands that the decision to permit operation as a pure EV compromised CS operation.

    It's far more interesting to me that the big pig Volt seemed to do better than the PHV Prius in your hands on a Wh/mile basis (if I recall correctly - too tired to look it up :) ). I really think they sweated the details on this car.

    You mentioned "close to WOT". My understanding is that, from a manifold pressure perspective, 80% throttle or so IS WOT at lower rpm. There's no measurable loss across the throttle plate.

    I've heard of the way the Sonata Hybrid drives. I find it hard to believe it's more efficient to do it that way (thought it apparently is) when the option exists for a direct mechanical connection. The Volt starts load sharing (GM's term) as early as 45mph - that's when MG1 can be clutched in. Despite the hysteria, it's not quite the same thing as a direct mechanical connection because MG2 must be spinning for power transfer to occur. So MG2 has to produce a little energy which MG1 consumes, losing a little on both sides of the transaction.

    The Volt ICE has a few advantages to counter the inherent energy conversion problems in series mode. First, it has reduced response requirements. A stab of the pedal is handled by MG2 and the ICE accelerates at whateve leisurely rate the engineer determined. That permits running aggressive timing for outsized improvements with premium fuel. It also means no need for WOT enrichment, which is probably the bigger advantage (though I have no firsthand knowledge).

    I imagine lots of yelling. :)

    As a few others mentioned, switching to MM at the beginning of the trip does nothing but reduce your EV range. I believe, but have not experienced firsthand, that all it does is change the SoC, nothing else. The super aggressive charging regimen you experienced is just the car struggling to get back up to that 45% ASAP, no different from normal CS mode if you managed to really deplete the battery with very hard driving.

    I really enjoyed your observations. It's a shame you couldn't have the car longer.
  13. herm

    herm Well-Known Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    "Readjust your mirrors so that you don't see them".. that actually works well until you get over this fear.. I picked it up accidentally many year ago driving a Chevette.. had a huge box in the back that completely blocked my rear view and I felt relaxed.. and I never got rammed from the back while driving many years at 55. Perhaps it should a standard training tool to teach newbies to slow down, cover up the mirror with a towel.
  14. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Hi Volterev:

    Regarding range, if you are in the confines of the Big Apple, the Volt’s range could prove itself mightily. In my drives, it was the city cycles where the range was really stupendous. I am thinking a drive along the Throgsneck (is that how it is spelled?) or any of the parkways with heavy NY based traffic. The medium speed ebb and flow is almost a natural for the Volt.

    Agreed. My week with the Volt consisted of 225 miles of CD and 120 miles of CS mode driving. If it were my own, I would have reduced its CS mode driving to < 5-miles. With the review, I had to get some CS mode miles in unfortunately :(
    I mentioned that in one of the review posts. For GM to create a quasi PSD based PHEV that weighs at least 500 pounds more than the Prius PHEV yet allows better energy efficiency in CD mode was impressive! Locking MG1 with the reverse PSD configuration did wonders for higher speed efficiency and I have to give GM a lot of credit for even thinking of it!

    2011 Chevrolet Volt PHEV - With the second and third charge of 13.13 and 13.54 kWh respectively (both more indicative of a standard charge from 0 to full vs. charge #1), the Volt’s 26,670 Wh/126.6 miles = 210.66 Wh/mile or (126.6 miles/26.670 kWh)*(33.7 kWh/1 gallon of gasoline) = 159.97 MPGe was a pleasant surprise over a 60% City/Suburban – 40% all-highway review.

    This is by comparison to the 2012 Prius PHEV which consumed a total of 20.85 kWh over 91 total EV miles 20,850 Wh/91 miles = 229.12 Wh/mile or (91 miles/20,850 kWh)*(33.7 kWh/1 gallon of gasoline) = 147.08 MPGe on a 20% highway, 80% City/Suburban review. In addition, the Prius was driven more to its strengths and yet still finished behind on a Wh/mile basis.
    Good stuff! When we talk about WOT, that is an area we never go. In fact, you would be surprised at how small a throttle input is needed to incur LOADS > 90% vs. actual WOT for BSFC maps in a conventionally powered automobile. That is why we like to discuss BMEP in order to find the most efficient areas for an ICE and they are usually found in the 70 to 80% LOAD area (in most cases) and at a TPS of just 1/3 to 1/2 of WOT.
    PSD getting in the way again and why Ford and Toyota have such a hard time receiving not only the highway speed under an EV/Glide (MG1 reverse rpm and current limitations) but also the FE that both engines would be capable of if the hybrid drivetrains were absent altogether. All else being equal, the Hyundai/VW hybrid systems that are clutched through a near standard AT minus the Torque converter are the bomb out on the super slab but in the city, both fail to produce the PSD’s FE numbers due to that overly cumbersome AT.
    I wish I had another two or three days with the Volt to learn more about its CS mode in this realm. It is that single statement from Ewanick about close to 100-miles of total range after an MM mode addition and the manual’s description of extending SoC range in anticipation of the Eisenhower tunnel for example that has me wondering and waiting for my next shot at a day or two behind the wheel of the mighty Volt :)

    Thanks again for your detailed insights regarding the Volt as everyone in this thread has learned quite a bit from your additions.

    Last edited: Jun 19, 2011

    VOLTEREV New Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Thanks Wayne keep up the great work. I will try my best to maximize mileage. I am in Long Island, New York and we have lots of lights here. Yes it's Throgs Neck Bridge :)
  16. Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Thanks Wayne. I enjoy participating in a pure technical discussion w/o wading through a million posts about the car being too expensive, too small, too heavy, paid for with tax dollars, etc. You certainly did the most thorough review I've encountered.

    Your results encouraged some changes to my driving behavior, giving a personal best 265Wh/mile with predicted ranges exceeding 50 miles for the first time. I won't claim I'll be making a habit of it though. :)
  17. Re: CleanMPG Reviews the 2011 Chevrolet VOLT Review Blog

    Thanks for waking me up to MM with this review, Wayne. I had never used it and never heard the associated ICE roar.

    Would you agree with the following summary of how best to use MM in the Volt? It is from a post by ClovisVOLT:

    After 11,500 miles many of which are using the ICE due to long commute every week, by far the best mileage has been obtained by using the ICE during "heaviest energy requirements" and EV mode during "lightest energy use" with Mountain mode invoked during all but the first 20-25 and final 12-15 miles of the trip and L only while in stop and go traffic - D when on the open road.

    This was not scientific and had many weather related variables, but every 168 mile trip has been a new experiment to try to tap out the trip with as little gas fuel as possible.

    My best thus far has been 3.2 gallons for the trip much of which is at 70-75 mph or above.

    Obvioulsy, start with full charge and pre-condition for an extra couple of miles gain, wait on selecting Mountain mode until less than half charge remains, once out of the city, set to D rather than L, when going less than 60 mph, swap into Normal mode until coming back upto full freeway speed or a serious hill.

    Whenever above 60-65 mph, unless drafting off another vehicle, swap back to Mountain to regen the battery for your next 'light use' stretch.

    By driving using this technique (along with near perfect wind and temperature conditions), was able to cut about 20% off gas fuel use (3.2 vs 4.0 gallons) and raise the "EV miles" to about half the trip miles. Clearly, Mountain to EV to Mountain to EV provides the best mpg available (if you use them when most adventagous)....again, based upon the 11,500 miles of experiments to date.
  18. Re: CleanMPG Reviews the 2011 Chevrolet VOLT

    Not sure if anyone still reads this but I learned that 2700/full load operation is, in fact, right around the "awesome point" where the conversion from fuel to charge is most efficient, which explains Wayne's results from gaming MM nicely.
  19. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT Review Blog

    We are definitely still reading this thread and we really appreciate the info!! Where did you find this particular bit?
  20. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Re: CleanMPG Reviews the 2011 Chevrolet VOLT Review Blog

    Hi Bill:

    It looks like he has a good handle on MM’s capability and use. I have only used the MM for one complete cycle under CS mode in a city environment so I am probably the last guy you want to take advice from regarding its use out on the super slab. Seeing his 52.5 mpg segment at 70 to 75 mph on the Interstate looks very enticing and that will dust every other hybrid on the open road including a Prius at that speed!

    AnotherVoltOwner, we read everything ;) Good to hear about the 2,700 R BSFC with the associated losses through MG1 conversions, upconversion and the pack prove it to be a very efficient area. 2,700 RPM is a lot of waste heat from the ICE's perspective but that massively parallel pack appears to take in MG1's current and laugh at all of us while giving it all back later :D

    Something I have not posted but wondered about. Around the 27 to 28 mph area under CD mode and accelerating, I felt a very slight bump in the drivetrain like the Volt was shifting gears. While there are no gears to shift, I felt this little bump maybe 15 to 20 X's but I have no idea what it was? It is so subtle that it would not even measure but it has me wondering about a peak speed vs. efficiency point while on the pack?

    I posted the final review write-up minus the extra detail disseminated in this thread in the review section last night: CleanMPG Reviews the 2011 Chevrolet Volt.


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