• 72
Chevrolet Volt – Click above for high-res image gallery

How clean is the Chevrolet Volt? According to the California Air Resources Board (CARB), the Volt is a ULEV (PDF link), an ultra low emissions vehicle. This means that the Volt – in this one specific way of calculating things – is dirtier than cars like the Toyota Prius, Honda Insight and Honda CR-Z.

How does CARB do the math for this? The full details are in this PDF, but the gist is that there are two tests CARB uses (known as the Supplemental Federal Test Procedures): a high-speed, high-acceleration test (US06) and the SC03 air-conditioner test. Emissions are measured and the results determine the vehicle's status (see a list of levels after the jump). The Volt did well in most categories, but not concerning carbon monoxide. CO limits for SULEV status is 1.0 grams per mile, while ULEV is 2.1 g/mi. Volt produces 1.3 g/mi.

The trick is that these tests need to be done with an engine running. Since the Volt doesn't need to burn any gasoline to move, under many circumstances – and the Volt engineers even needed to develop a maintenance mode to deal with the new problem of aging gas in the tank – the Volt is a special beast and, probably to GM's dismay, it doesn't benefit from its battery-only ability in this test. CARB's LEV III ruleset proposal would include a way to include these vehicles in the categories.

Still, the Volt will burn gasoline, and now we can compare it to other vehicles that do so. Informational charts are available after the jump and there's more over at Prius Chat. Thanks to usbseawolf2000 for the tip and the chart!

[Source: CARB, Prius Chat]





carb levII criteria


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 72 Comments
      • 4 Years Ago
      It's common for car makers to sell cars with essentially the same drivetrain but different pollution scores. I haven't looked into this much but from what I have read it is mostly about the catalytic converter. Getting the lowest emission score requires using a fancier and more expensive converter.

      GM may have gone the direction they did for any number of reasons including: the engine is just a backup and frequently won't be running at all, they wanted to focus their R&D for the 1st generation on non-engine areas, or they had size constraints that prevented them from using a higher quality converter.

      Unlike most cars which have the converter under the car, i believe the Volt has its converter bolted near the exhaust manifest on the engine. They may have done this for aerodynamic reasons to smooth the airflow under the car, to keep the heat of the converter away from the battery pack or for some other reason.

      Here's an example of two variations of the 2010 Malibu that appear identical in EPA's emissions database except one is rated LEV and one is rated SULEV. I'm guessing the LEV is sold nationally and the SULEV is sold in (high pollution areas of?) California for regulatory reasons but I haven't tracked that down.

      http://www.epa.gov/greenvehicles/Compareresult.do?vehicle_ID=123022&vehicle_ID2=123024

      GM has recently restated that they plan for the Volt to meet SULEV pollution standards in model year 2013.
        • 4 Years Ago
        quote from Jeff N: - "Unlike most cars which have the converter under the car, i believe the Volt has its converter bolted near the exhaust manifest on the engine." -

        Most modern cars(more every year anyhow) have the catalytic converter located as close to the exhaust manifold as possible to aid in light-off. The cats only work once they reach a certain temperature and locating them closer to the manifold helps to heat them more quickly and allow them to work properly. Tightening emissions controls have made this virtually mandatory.
        • 4 Years Ago
        GM is making a lot of claims of plans for new additions, but it is dependant on whether or not the IPO goes well and they are able to access the $14.4 Billion in new DOE funds they requested. If they can't get the new stream of government funds, don't expect many of their future plans to go through.
        • 4 Years Ago
        Outside CARB areas right now, the required maximum fleet average for emissions is the same as the maximum allowed emissions for any vehicle (tier 2 bin 5). So once a car passes tier 2 bin 5 (which is the same as LEV II), there's no advantage to making it lower emissions.

        In CARB, the required fleet average is lower than the maximum for any individual car (tier 2 bin 5/LEV II) and so you must sell some percentage of your cars with lower than LEV II emissions certification. In order to meet this requirement, car companies will generally make a version of their most popular car that is certified to SULEV. But they only need to sell as many of those as it takes to get the average down, so many of them aren't SULEV even though a car that is identically configured and built at the same time might be. So in California some Malibus will be LEV II, some will be SULEV (II).

        GM says the Volt will meet atPZEV later, this is tighter than SULEV (II) and PZEV. Of course, promises are one thing they need to deliver on the promises to really make a change.
      • 4 Years Ago
      "Yes, because everyone who lives in CO lives on the side of a mountain.
      Just because a lot of the state sits above a mile high doesn't mean that we climb mountain passes on our daily commute(though I wouldn't be disappointed if I did)."

      Well for my frame of reference of Colorado, my in-laws live in COS and my sister in Greeley. I drove from the Springs to the Denver airport yesterday.

      If you live in Greeley, then you probably don't need mountain mode much. If you live in Colorado Springs and many areas around Denver, then you would probably need it on a regular basis. Mountain Mode reduces battery range to comparable to a plug-in Prius and needs to be engaged 10-15 minutes before going up in elevation. It also consumes more gasoline than regular gasoline mode in order to store up reserves. If you know you are going driving on flat ground and aren't going up in elevation, then you may not need mountain mode. If you think there is a possibility you will, then you would need to have it on ahead of time.

      If you live in a mountainous area, you would probably be better off with a Prius, which gets better mileage running on gasoline and doesn't need a special mode to go up inclines.
        • 4 Years Ago
        What kind of car do you drive? Is it 4000 lbs with a 65 hp engine?

        Just remember that the Volt is a car with a 65 hp gasoline engine with a relatively high-loss transmission in a 4000 lb car (including one driver)... And altitude reduces horsepower by ~3 percent for every thousand feet-- making it ~50 horsepower at 6000 feet. If you wanted to be safe in cold weather, you would want the ability to climb a long grade.

        Also remember that climate control, accessories, etc. will reduce electric range in a Volt.
        • 4 Years Ago
        I agree with montoym's excellent reply but I wanted to clarify the difference between our charge threshold numbers. I used 20% for the normal lower threshold before the gas engine starts and 35% in Mountain Mode while montoym used 30% and 45%. In both cases the difference is 15% of the nominal 16 kWhs of the Volt battery pack.

        My numbers reflect the public disclosure a couple of weeks ago by GM that the Volt's normal lower and upper State of Charge thresholds have been widened to allow use of 65% of the nominal battery. The numbers from montoym are based on older threshold numbers that reflected a 50% range of use. That's why GM now talks about an all-battery range of up to 50 miles versus the old upper limit of 40 miles.
        • 4 Years Ago
        The power of the range extender is somewhat inconsequential. The engine they have chosen will be just fine.

        Why is this?

        Simple. The ICE does not directly drive the wheels, the electric motors provide virtually all of the motive force(except for speeds greater than 70mph and in CS mode when the ICE helps out a bit). The primary electric motor is 110kW(149hp) not 65hp. It's power is also not affected by air pressure changes as an ICE is, it's still making 149hp at 10k ft(and 273lb-ft as well).

        Therefore, the ICE doesn't have to instantaneously provide the power that is needed at the wheels to maintain speed. That duty falls to the batteries. The batteries provide a large buffer which the motors draw from when they need power. The ICE only has to maintain this level of charge, it doesn't have to directly account for the spikes and valleys that occur on a typical drive.

        Put another way, as I've stated in at least a few other comments about the Volt, how often are you at full throttle in your own vehicle on a daily basis? My guess is possibly never, but probably rarely. So why do you expect the Volt to have to provide full throttle power(67hp) all the time just to maintain charge? Disregard the fact that the ICE isn't super-powerful, remember it's not directly powering the wheels.

        Think of your daily drive as a graph with points plotted on it based on your throttle input over time. The moving average of that line is what needs to be maintained, not the individual spikes when you were at full throttle for a brief few seconds, those are absorbed by the battery and replenished by the ICE over time, not instantaneously.

        For the record, the 1st and 2nd generation Prius's(?) also have pretty underwhelming IC engines and they seem to perform perfectly adequately in the high altitudes of CO. I routinely see many 2nd-gen versions doing well over the speed limit, keeping up just fine with other traffic despite their 67hp(at sea level) engines, even up I-70 on the way to the mountains. In the case of a Prius, the ICE(67hp) is actually providing the majority of the motive force to the wheels, unlike a Volt where the electric motor(149hp) is the prime factor.

        • 4 Years Ago
        Bull.

        I do live in COS and I guarantee you that you would not need Mountain Mode any more often than you'd need it anywhere else there are hills. Again, just because the elevation is high doesn't meant that every road is a steep climb.

        The biggest elevation change from COS to Denver is Monument Hill just north of Colo Spgs. The couple of miles it takes to climb the 1500ft or so that it sits above Colo Spgs isn't going to wear down your battery such that Mountain Mode is even remotely necessary. Plus, once you pass Monument Hill, it's a pretty steady drop all the way to Denver since Denver sits below Colo Spgs by almost 1000ft. DIA is lower still.

        Going back to Mountain Mode, you still are misrepresenting how it works.

        If you engage it 10-15min before you expect to climb a large grade, it would only kick on the ICE is you are already below the charge threshold for Mountain Mode(said to be about 45%). If you are still above 45% then the ICE stays off until you reach that figure(as opposed to the 30% or so figure when Mountain Mode is not engaged). it will maintain that 45% though once you reach it.

        For this same reason, you will not be burning up any additional fuel in order to "store up reserves" unless you were already below that 45% when you engaged it.

        You are blowing Mountain Mode way out of proportion. They've designed the Volt to be able to tackle any grade of road that you might find in the US, but what you are talking about barely registers on that scale.

        The US Interstate system allows for grades as steep as 6%(vertical change of 6ft per 100ft of roadway). I can only think of a couple of areas in CO where you would find grades that steep on the Interstate. As a byproduct, due to those steeper grades, the sped limits are generally also decreased as well. For instance Floyd Hill on I-70 West of Denver is a good example. It's a fairly steep grade as you are getting into the foothills. The speed limit in that area is about 55mph but increases to 65mph once you pass the steepest area.

        It's really only a factor on higher speed roads as well since slower speeds will dramatically decrease the power needed to climb those grades and it becomes even more of a non-issue.

        Jeff N right below describes Mountain Mode well also.
        • 4 Years Ago
        I drive a 2004 Prius which weights 3060 (driver included) and has a 76hp gas engine,

        The Volt has an 83hp gas engine (74hp/55kW generating) and will weight 3940 when I'm driving it but it also has a battery that can put out 111 kW of power and a 149hp electric motor to take me up the hill.

        If I'm going up a mountain after the lower battery threshold has turned on the gas engine then any heat for the climate control will come from the engine coolant as in a conventional car.

      • 4 Years Ago
      There is no evidence that Mountain Mode is needed for normal driving though typical mountain roads. It was added to allow full power driving in 5-10 of the most severe mountain passes like Pike's Peak. A GM employee just drove through the I-5 "Grapevine" from the Central Valley into LA over the Tejon Pass at normal speeds without using Mountain Mode. That drive includes long 5-6% grades and a total elevation climb of 4,000 ft. and is fairly challenging for conventional cars.

      Here's a description:

      http://www.dot.ca.gov/dist07/Publications/Inside7/story.php?id=97

      "Ine937s" says: "Mountain Mode reduces battery range to comparable to a plug-in Prius".

      The usable battery range of a plugin Prius is slightly more than 3 kWhs. The Mountain Mode adds an additional 15% of the Volt's total battery capacity of 16 kWhs to the usable State of Charge range so instead of 20-85% or so it becomes 35-85%. That still leaves 50% of the nominal 16 kWhs available for a usable 8 kWhs. Of course, you probably start out with a full usable 10.4 kWhs before approaching Pike's Peak and turning on Mountain Mode so comparing the Volt's capacity to the 3 kWhs of the plugin Prius doesn't make sense.

      Finally, I drive a gen 2 Prius and although it spins up the RPMs going through mountains and does just fine it also gets "altitude sickness" from the thin air up around 10,000 ft. like most cars with gasoline engines. However, a Volt in Mountain Mode will likely see little difference in performance because the batteries and electric motor don't care about air pressure changes over mountain passes.

        • 4 Years Ago
        And finally.....

        Recent test driving reports on the current Toyota Plugin-in Prius prototype report that the regenerative braking may not recharge the extended range batteries and may only charge the regular Hybrid battery which only has a nominal capacity of 1.5 kWhs and which Toyota normally tries to keep within a narrow SOC that is probably well under half that amount. So, coming down Pike's Peak, a Plug-in Prius may only be able to regeneratively recharge it's batteries with about 2-3 miles of charge versus 15-20 for a Volt.

        • 4 Years Ago
        Oops, I understated things a bit. Mountain Mode gives you a SOC range of about 35%-85% of the nominal 16 kWhs but the whole point of it is that in the steepest and longest ascents it will still allow the battery to dip down to around 20% SOC if the gas engine temporarily can't keep up. So the full range of 10.4 kWhs is still available but the gas engine tries to keep the battery charged at 35% instead of 20%. Coming back down Pike's Peak you should be able to recapture 4-5 kWhs.

      • 4 Years Ago
      WOW. According to priuschat, the Subaru WRX STI, a LEV car, emits less CO/mile than the Volt. I looked for numbers on other cars but they are not easy to find..

      How did GM pull this off? Is it because the range extender only runs at full ( or near full ) power at all times? Is it because there is less emissions equipment in order to gain a little more power since the 1.4L is probably REAL underpowered?

      I guess you have to consider that it won't run in RE mode all the time, but.... that's still bad.
        • 4 Years Ago
        Nah, i just get email alerts.
        I don't sit on autoblog all day hitting the refresh button.

        And yes, saying anything good about the Volt is FORBIDDEN ;)
        • 4 Years Ago
        "I was waiting for you to come on here and try to defend the Volt in some way."

        Heaven forbid someone says something good about the Volt... Not on Middle Way's watch! Pretty sad that you have the time to wait for someone to "come on here and try to defend the Volt in some way." So you dont like the Volt, we get it. Im sure many other people are really excited about the Volt. Really, whats the point of insulting them?

        You really need to find something better to do with your time. Find a forum on Hummers or something and troll there.
        • 4 Years Ago
        Agreed Middle Way, the regular Prius has lower emissions than the Volt. If you are going to drive in range extended mode often, emissions-wise you'd do a lot better getting a Prius than a Volt. But then again we already knew that if you're going to drive in range extended mode often, you'd do better in all ways to get a Prius over a Volt.

        The Prius is a very clean, very efficient machine. Short of plug-ins, it's difficult to match it. Which is why it beat out so many competitors, including GM's so-so hybrids and Honda's good ones.
        • 4 Years Ago
        That rating compares the Volt to a car you can't even buy. You remember all those 2010 plug-in Priuses that Toyota sold? Yeah, me neither.

        What's the point in that comparison?
        • 4 Years Ago
        I would say poor emissions controls, because there are many non-hybrids with much more powerful gasoline engines that are rated PZEV/SULEV; including large MBs and Volvos with 6-cyl engines, automatic transmissions and AWD..
        • 4 Years Ago
        I was waiting for you to come on here and try to defend the Volt in some way.

        How about this... the Plugin Prius and regular Prius have very similar numbers. There is a comparison in that thread.

        If you think of the regular Prius as always being in range extender mode.. and compare it to the Volt in range extender mode.. the Volt looks really bad. The Volt looks bad even compared to normal gas-only cars in RE mode too.
        • 4 Years Ago
        Apparently 7500 miles in extended mode in the Volt would approximately equal 150,000 miles in the Prius. I guess it really comes down to how often you're hitting the extended range mode, and how many emissions the forced maintenance mode will give off (the one to keep the gasoline from going stale).
        Still, I think the Volt will be a relatively clean car so long as you're not always using the extended range. It's just that the Prius has rather impressively low emissions that seem to far exceed the requirements.
        • 4 Years Ago
        I think the engine is sort of choked or the exhaust is recycled more. This is what this particular engine does to increase it's range.

        Similar to any engine the speed and the air intake are usually optimized for a specific RPM and HP output (remember "tune-port-injectors?").
        • 4 Years Ago
        Yeah, it's true that you won't always be driving it in range extender mode, but that's a major reason that you buy the car and spend the extra $10k over an electric car, am i right? Otherwise the Leaf, Focus EV, etc would be a completely obvious choice.

        I think the comparison to the Prius is fair, as it provides a clear picture of how each car uses gasoline. You can't factor in the electric mileage because you could technically drive this car forever without a drop of gas. Everyone's commute varies. Some people have a 80+ mile round trip to work.. some have a 10 mile round trip commute..

        I guess the truth is that i care about fuel economy and emissions more than most. If i, for some reason, owned this car, I would dread the range extender coming on. The electric range is nice, but it's a Dr. Jekyll & Mr. Hyde type of affair that gets to me. It would be nice if Mr. Hyde was a bit less evil :p.
        • 4 Years Ago
        But Middle Way, a Volt is only rarely in range extender mode. The whole point of the Volt is that the vast majority of your driving would be in all electric mode. Your comparison is skewed.
      • 4 Years Ago
      Which begs the question regarding the Volt - What's the point?

      Its expensive
      It's not really an EV, it's not really a Hybrid either
      It won't give you driving pleasure
      It still uses fuel
      It only seats 4 people max
      Now we find out the engine is more dirty than existing green hybrids
      While gasoline cars needs to burn gas to get going, the Volt needs to burn gasoline just so the gasoline doesn't sit too long. I mean seriously, what kind of irony is that.

      On a side note, what's CARB going to do with the Leaf? I heard there is no emission aside from the Carbon Dioxide emitted from the occupants.
        • 4 Years Ago
        "Of course, all this only matters if one buys into the whole CO2=bad premise. Seem to be a bandwagon thing to me."

        You know, 99% of the the time it's GOOD to be a Conservative. But, when Russia's wheat harvest is nearly wiped out by 600 Wild fires, 2000 deaths to Moscow heat wave, and 20% of Pakistan flooded, it's time for even Conservatives to wake up.

        Look at it this way, 600 wild fires across the South, how long before Rush Limbaugh get's Lynched by his own Party?

        There's a time for conservatism on an issue, that time is over.
        • 4 Years Ago
        "Its expensive"

        New tech is funny that way.

        "It's not really an EV, it's not really a Hybrid either"

        It's both. I don't understand why people can't comprehend that.

        "It won't give you driving pleasure"

        VERY subjective and relatively unfounded.

        "It still uses fuel"

        Just very little of it.

        "It only seats 4 people max"

        Twice as many as the Tesla Roadster. Also, I can't remember the last time I had more than four people in my car. I'm not sure it's ever happened.

        "Now we find out the engine is more dirty than existing green hybrids"

        Read the report. It's bullshit. The Volt is very clean. They're just messing with the numbers.

        "On a side note, what's CARB going to do with the Leaf? I heard there is no emission aside from the Carbon Dioxide emitted from the occupants. "

        The article was going on about Carbon Monoxide, not Carbon Dioxide, but let's not bother ourselves with such detail....

        Ignoring how the electricity is made, your statement is correct. I find it fascinating that we put so much focus on the CO2 emitted by cars, when living things produce so much CO2. Of course, all this only matters if one buys into the whole CO2=bad premise. Seem to be a bandwagon thing to me. Like everything else, a proper balance is what's needed. In NA, we're in balance.
        • 4 Years Ago
        The point is its currently the closest thing to an EV that wont leave you stranded. The biggest issue with the adoption of EVs is range anxiety. GM wont be the only automaker using this configuration. There is actually a pretty good point.
        • 4 Years Ago
        @nrb,

        "I find it fascinating that we put so much focus on the CO2 emitted by cars, when living things produce so much CO2."
        That's because you've not educated on the subject. Read http://en.wikipedia.org/wiki/Carbon_cycle Living things participate in the carbon cycle. Fossil fuel takes carbon that's been sequestered for millions of years and burns it, raising atmospheric levels of greenhouse gases.

        "Of course, all this only matters if one buys into the whole CO2=bad premise. Seem to be a bandwagon thing to me."
        Really? We need CO2 to live, therefore any amount of it is good even a doubling of atmospheric CO2 levels? You should be embarrassed to be so stupid in public. The *increase* in the levels of those greenhouse gases is 95% likely the main reason for the undeniable increase in global mean temperatures we've seen in the last 50 to 150 years, and will affect it more in the future. This "bandwagon" is an undeniable physical process that was identified and quantified 114 f***ing years ago by Svante Arrhenius; I first heard about it over 25 years ago.

        "Like everything else, a proper balance is what's needed."
        Definitely, a proper balance being 260 ppm atmospheric CO2. Right now we're at 390 ppm CO2. Methane concentrations are up even more.

        "In NA, we're in balance."
        Where do you and "Stan Peterson" get that idea? America is the second largest net CO2 emitter after China. To repeat my correction to him, the EPA sequestration FAQ http://www.epa.gov/sequestration/faq.html says "The U.S. landscape acts as a net carbon sink—it sequesters more carbon than it emits", but industrial emissions dwarf that. From the UNFCCC site http://unfccc.int/ghg_data/ghg_data_unfccc/items/4146.php, in 2008 USA emitted over 6.9 billion metric tons of CO2 equivalent greenhouse gases even when you include the sequestration from Land use, Land-Use Change and Forestry".
      • 4 Years Ago
      GM hopes this is successful and so do the other auto corps save for Nissan. They will use words such as stranded and range anxiety in hopes of goading the public into believing that EV's are not viable unless their is a ICE on board, keeping one hundred years of revenue streams for the ICE intact.

      IMO, the Volt will help. It will help the public if they do buy a Volt. They will drive in EV mode and realize they can do away with the ICE all together and buy a real EV and despite the confusion we know what a real EV is, it does not burn oil, foreign or other.

      As JoeV said, "common sense is not so common".
        • 4 Years Ago
        "The only reason... here in Colorado."

        Just remember that living in Colorado (unless you live in the eastern part that looks like Kansas), you will need to operate a Volt in "mountain mode" which makes it run on gasoline- and is not very efficient in that application. If a pure EV doesn't work for you, you would save more fuel with a Prius.
        • 4 Years Ago
        quote from lne937s - ""The only reason... here in Colorado."

        Just remember that living in Colorado (unless you live in the eastern part that looks like Kansas), you will need to operate a Volt in "mountain mode" which makes it run on gasoline" -

        Yes, because everyone who lives in CO lives on the side of a mountain.
        Just because a lot of the state sits above a mile high doesn't mean that we climb mountain passes on our daily commute(though I wouldn't be disappointed if I did).

        Mountain Mode wouldn't need to be used as often as you might think. On your way to a ski trip in Summit County, yeah probably(especially if you want to do 80mph like 75% of the traffic up I-70). But on your daily commute to the Denver Tech Center, downtown, or for 80% of the rest of your driving, not likely.

        BTW, Mountain Mode doesn't make it run on gasoline, it simply starts charging the batteries with the ICE earlier than if you didn't run it in Mountain Mode. It doesn't automatically kick on the ICE unless you are already below the minimum charge threshold. It allows a larger buffer in the battery's charge to counteract the greater power demands of severe mountain driving.
        • 4 Years Ago
        I totally agree with Chelsea Sexton. However, I am concern with the Volt driven on the gas engine (CS mode). For example, the highly promoted Freedom drive from Texas to NY. It was suppose to ease the Range Anxiety.

        Volt's CS mode is known to get sub-par non-hybrid MPG. It's emissions are worse than Cruze (non-hybrid cousin). It also uses premium gas when Cruze uses regular (even the turbo version).

        There are a lot of anxiety revolving around the Range Extender for above reasons. GM has to be careful playing the "anxiety" card. It might backfire on them.
        • 4 Years Ago
        Middle Way, it doesn't matter whether gas prices go up or not. The Volt does not make sense from a pure cost of ownership perspective. Gas would have to at least double to make the Volt or a plug-in Prius even give it a run for its money.
        • 4 Years Ago
        Middle Way makes a great point. On long trips or big commutes the Prius is the better car.

        Still, a zero gas bill, and [ near ] zero emissions when you park your car in your garage, is also appealing.
        • 4 Years Ago
        The only reason I could not settle for the Leaf is the lack of charging stations here in Colorado. That and the fact that sitting in traffic during a snow storm with the heat cranked may leave me wishing I had that range extending ICE to get me home. Im confident that the technology will get there soon, it just isnt there yet.

        Full EVs still present a compromise. The Volt presents a solution to that. Its a stepping stone to a world with much less oil dependence. So I partially agree with you.
        • 4 Years Ago
        It's an EV with training wheels.

        I think when the gas prices go up, this car will be far less of a joy to take on long trips. low-high 30mpg isn't too bad. But you'll get range extender anxiety and prius envy... hehe
        • 4 Years Ago
        "I don't have a problem with someone buying a Volt. I'm concerned about as many electric miles as possible."
        -- Chelsea Sexton
      • 4 Years Ago
      The evaporative emissions of the Volt surprised me more than anything.

      http://priuschat.com/forums/attachments/gen-iii-2010-prius-main-forum/26276d1287512095-emission-comparison-prius-hs250h-insight-civic-hybrid-jetta-gas-tdi-wrx-sti-volt_evap.png

      For a car that will be burning little fuel, if used properly, should have had emissions far less than the Prius, Insight or CRZ. I wouldn't want to let a tank of gas sit too long in a Volt.
        • 4 Years Ago
        CH:
        All of these emission are in grams, your point? We should junk all emissions standards because cars are pretty good as it is? Evaporative emissions are not the same as CO2 emissions, they are unburnt hydro-carbons, and are much, much worse. The point of evaporative emissions isn't that you will have less gas in your tank to drive with, but that you are dumping toxins in the environment. For a fleet of 100,000 vehicles, that’s 900 gals a year. For 1,000,000 you are talking about 9,000 gal a year just dumped into the environment.
        • 4 Years Ago
        The evaporative emissions are so low on either car they are difficult to measure well. As an example of this, look at the Prius evaporative emissions ratings. The car emitted more emissions in the 2 day test than in the 3 day test! So did the Insight.

        There's just too much variance in these tests and the figures are too low to get excited about the measured differences shown here.

        For example, an EV is allowed to emit 0.35 grams per test on tests soak tests merely because the paints, upholstery, tires and such will outgas during the test. This even though an EV is not allowed to emit any fuel-based evaporative emissions during the test.
        • 4 Years Ago
        The hot-soak evaporative emissions are mostly due to how well sealed the fuel tank and fuel lines are. Toyota spent big bucks on their fuel system. ( http://www.autoshop101.com/forms/Hybrid13.pdf) I wonder how high a priority it was for the Volt.

        The irony is the Volt polutes twice as much as the Prius when both are sitting in your driveway. The size of the battery or the design the transmission doesn't mean much if you don't spend sufficient $ to keep the fuel from just evaporating from the tank.
        • 4 Years Ago
        "The irony is the Volt polutes twice as much as the Prius when both are sitting in your driveway. The size of the battery or the design the transmission doesn't mean much if you don't spend sufficient $ to keep the fuel from just evaporating from the tank."

        DB, you need some perspective. The Volt emitted 0.25 gram more of gasoline than the Prius on the 3-day test. That's 0.00009 gallon of gasoline, which pales into insignificance compared to the savings from increased battery size or a better transmission; let alone the fact that the Volt can cover most people's daily commute without burning any gasoline or producing any other pollutants at all.

        I think many people focus on relative comparisons of selected while losing sight of the big picture and paying absolutely no attention to materiality.

      • 4 Years Ago
      "An ultra low emission vehicle"?

      I guess anything is better than diesel! We must take small steps to stop pollution!
        • 4 Years Ago
        Uh, check your numbers. There are a lot of things worse than diesel. Change the equation to biodiesel or algae diesel and EVERYTHING is worse than diesel.
      • 4 Years Ago
      If your driving needs land you in a category where you need a single car that is efficient for both short trips and frequent long trips, the Volt is obviously not the right car for you. If you buy one and end up using it mostly for long trips, you should sell it and you probably will. This is likely only going to happen to a rare few that have a life changing experience, like a sudden new job with a much longer commute. If you bought the Volt knowing you would be using it mostly for long trips then you are an idiot.

      This problem is obviously even worse for the Leaf owner and is no different than if you own a sport utility with a big V8 and then suddenly you find yourself commuting alone in it for long distances... you should sell that vehicle and buy one more appropriate for your use case.

      The point here is that everyone should attempt to match their vehicle choice with their transportation and utility needs. That said, to test the emissions of the Volt as if it didn't have any all-electric range at all is just disingenuous, as this will not be the use case for the vehicle except in rare and temporary circumstances and in fact is exactly the opposite of the intended use case.

      Test the vehicle in the way it is intended to be used.
      • 4 Years Ago
      I can't help but think we're comparing apples and oranges here.

      If you drive short distances ONLY, get a Leaf.

      If you drive mostly in city traffic with a few longer trips, get a Prius.

      If you drive shorter distances most of the time, with occasional longer trips, get a Volt.

      If you drive primarily longer distances, get a diesel.

      Pretty simple if you think about it. There is NO SINGLE BEST solution, only BEST for YOUR NEEDS.
        • 4 Years Ago
        Some people just seem to think that there is one single car out there that is perfect for everyone.
      • 4 Years Ago
      GM wanted to make a "sporty" hybrid. This is the result - they have to live with it.
        • 4 Years Ago
        Actually, have you been paying any attention? Honda are the ones trying to make "sporty hybrids" (i.e. CR-Z). The issue the Volt's facing with this test is that it's being required it to do something (run on ICE only) that it's not been designed to do.

        I'm not even sure how they got it to run in a completely non-EV mode. If they needed to modify the vehicle to make it testable, then it completely invalidates any result.

        The traditional hybrids benefit here from their electric assist, which decreases strain on the ICE during higher load situations (as are being tested here). If they managed to get the Volt into ICE running mode by completely exhausting the batteries, then they would have been subjecting the engine to the demands of providing 100% of the energy needed to power the drive motors. The downfall of the Volt in range extending mode is that converting the energy in gasoline to electric energy and then converting it again into forward motion results in parasitic loss, only some of which is regained during events such as regenerative braking, etc and, even that is of zero benefit in this testing.
      • 4 Years Ago
      Dan,

      That's for sure not fair if true!!
    • Load More Comments