Hypothetical question - Prius minus the HSD

Discussion in 'Gen 2 Prius Technical Discussion' started by Ophbalance, Mar 11, 2012.

?

Does the HSD matter at any speed?

Poll closed Mar 25, 2012.
  1. Yes

    18 vote(s)
    100.0%
  2. No

    0 vote(s)
    0.0%
  3. I seriously don't care!

    0 vote(s)
    0.0%
  1. Ophbalance

    Ophbalance Member

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    I entered into a conversation on another forum because that evil Dust to Dust topic came back up. In the course of discussion, a different user came up with "A Prius is no better than any other car at highway speeds".

    I've disagreed. His/her point seems to be that any pack usage on the highway is a net zero equation, and that if the Prius existed as straight gas only, the results of a highway trip would be the exact same as one with the HSD.

    I've tried to point out that the HSD works at any speed, and recatpures energy at all times. This user seems to stand upon the idea that having a battery pack only is a net gain under "xx" MPH... I take it whatever speed the car can run fully electric.

    I've tried to point out that none of the energy that went into the pack is "free", the potential energy that's there can only come from gas engine (plug-ins excepted... or if you have someone tow it to the top of a hill/mountain).

    So I posit this to the group: does the HSD matter at highway speeds? Or is it as the opposing view says, it's a net zero game? I've put my money on the "HSD matters at any speed".

    This isn't an invitation to spam that other board, I'm just curious to see if anyone's views match mine.
     
  2. cwerdna

    cwerdna Senior Member

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    Which non-PHEV/non-EV at The most fuel-efficient cars and Best & worst cars review, fuel-efficient vehicles got better highway mileage than the Prius?

    Here are the results from the 2nd gen: http://web.archive.org/web/20081231...-advice/most-fuelefficient-cars-206/index.htm.

    It's unfortunate the CNW junk science still refuses to die :mad::rolleyes:, please feel free to use Environmental - Prius Wiki and Lifespan/Operating costs - Prius Wiki as aids. I was tired of always digging thru old Priuschat posts (some my own) for relevant URLs.

    Since there's no non-hybrid Prius, a decently close comparison would be highway mileage of the Matrix (since it also has a 1.8L 4 banger). See Best & worst cars review, fuel-efficient vehicles for its results. One can also look there for HyCam vs. regular Camry results. Also look at http://web.archive.org/web/20100820...-fuel-economy/best-and-worst-fuel-economy.htm for older HyCam vs. Camry and NAH vs. Altima results.

    Last page of http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf describes CR's tests vs. the old EPA tests.

    One can also consult http://www.fueleconomy.gov/feg/sbs.htm for EPA ratings.
     
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  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I see regen even over 70 MPH, so it is saving me money. Far MORE imortant is that you would never make to TO 70 with out the HSD to add power when accelerating.

    The reason you never see atkinson cycle engines without battery packs is acceleration would rival watching grass grow.

    (I have owned several cars with less than 70 HP, the Prius is a powerhouse by comparison)
     
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  4. bisco

    bisco cookie crumbler

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    i get 55 -60 mpg at 55mph. can a civic or corolla do that? and they are smaller.
     
  5. wick1ert

    wick1ert Senior Member

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    That sounds like the speed my Geo Metro accelerated to 60 at lol. IIRC, that little 3 banger had a mind blowing 55 HP.
     
  6. Ophbalance

    Ophbalance Member

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    I wonder if it's not just a strawman argument at this point anyway as things like this have happened:

    Other User: "I'm not even going to bother if you say things like 'You know not of which you speak'. It's arrogant."

    When pressed for a gasoline non hybrid that can match the Prius on the highway, it was the Civic CRX (which I had to correct him, he actually means the CRX HF). I pointed out that it's not really a fair comparison to match a lean burn Honda that stopped production 20 years ago against a 1000 pound heavier Prius from 2005.

    Also, this user tried to get away with "Anyone could make a Prius without the HSD that would get the same mileage".

    I pointed out that no one in the US would buy such a thing as it'd never accelerate out of its on way. Otherwise we'd be up to our ears in such cars right now.

    He rejoined with "I know that no one would buy one!". Then, I guess not just anyone can make such a beast?

    I think that without a direct comparison, this person is always going to believe that a Prius is only good for city use, and never for highway. The only thing I have left to point out is something like the Enginer system that feeds power back into the pack. But the only trouble with that is it's power coming from another source, and therefore doesn't fit into the proving it's not a net zero game.
     
  7. cwerdna

    cwerdna Senior Member

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    Not to mention that the CRX HF had less than 1/2 the horsepower and seats only two. Sigh...

    And per Twenty-year-old Civics got 57 miles per gallon - Dec. 19, 2007
     
  8. fotomoto

    fotomoto Senior Member

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    Can a non-hybrid car achieve better than 48+ mpg at hwy speeds? Yup. I had one over 25+ years ago: 1984 Honda CRX HF. But it only seated two, didn't have NEAR the modern emissions and safety equipment nowrequired by law and marketing, and was even slower than a Prius. From wiki:

    the 1.5 liter is rated by the [ame="http://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agency"]U.S. Environmental Protection Agencyā€ˇ[/ame] (EPA) (under the new rating system) at 41 miles per U.S. gallon (5.7 l/100 km; 49 mpg-imp) city and 50 miles per U.S. gallon (4.7 l/100 km; 60 mpg-imp) highway.[1]

    At a constant hwy speed, a traditional ICE automobile can achieve great mpg but that's not real world as we all have to slow down and speed up and the hybrid design can capitalize on that.
     
  9. Ophbalance

    Ophbalance Member

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    I did point out much of what's in the quote. The fact that my car comes with front/side/rear airbags, NAV, BT, 6CD, and seats 5 plus luggage. And that a CRX would never pass current safety standards acceptably.

    Now, I DID own an 87 Civic once upon a time. And even with my bashing the heck out of it and keeping it closer to 75+ most of the time, it did return in the low 30s for MPG. But then, I'd never ever ever want to get into an accident with it.
     
  10. Ophbalance

    Ophbalance Member

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    Something I pointed out on the other thread; the CRX HF was one of the magic Lean Burn Honda offerings. Stunning when in lean burn, hell on NOX though.
     
  11. qbee42

    qbee42 My other car is a boat

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    A non-hybrid Prius operating at highway speeds could get better mileage than the current hybrid version. In fact it would be pretty easy to do so. Unfortunately cars don't get to drive at just highway speeds. This highway optimized Prius would be virtually undrivable at other speeds.

    Tom
     
  12. fuzzy1

    fuzzy1 Senior Member

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    "Any other car" generally means those with Otto cycle gasoline engines. Do any of them match the energy conversion efficiency of the Atkinson cycle engines in Prius and several other hybrids? I don't think so. Only diesels have any chance.

    Then there is the transmission gearing issue. I do believe a simple manual transmission could beat the HSD efficiency at any one specific speed and load condition per gear. But "any other car" is going to need something like a 30 speed transmission to adequately match the engine speed to the road speed over the full gamut of operating conditions. The cost, weight, and internal friction of that transmission are going to be serious problems, and few drivers will put up with that much shifting in either a manual or an automatic. And even the available mechanical CVTs can't match the HSD's total effective range of gear ratios.
     
  13. cwerdna

    cwerdna Senior Member

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    Also, the other guy should go to Power Search and search for 2011-2013 cars powered by gasoline or diesel w/highway mpg >45 mpg. See which ones come up. :)
     
  14. Ophbalance

    Ophbalance Member

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    Good thoughts. At last look, he's fallen back on "Buying a Hybrid to drive 80 MPH on the highway are blowing the point of a hybrid". Another point I disagree with.
     
  15. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I drove a 1976 Mazda 808 Mizer station wagon with 59 HP and a 4 speed manual.
    Going uphill it could not 'pull' fourth gear, leaving you with a top speed of 37 MPH in third. On the Freeway, with a 70 MPH limit.

    My 1978 GLC had the same engine, but a 5 speed manual, much better. Or maybe the 'new' 55 MPH speed limit made it seem better.

    Mazda C engine - Wikipedia, the free encyclopedia
     
  16. fuzzy1

    fuzzy1 Senior Member

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    ^^ That 'new' 55 mph limit dated back to 1974. Your 1976 slug shouldn't have seen a 70 mph speed limit sign until it was at least twenty years old.
     
  17. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    The answer is that, yes, at high speeds a conventional gasoline vehicle could be more efficient, because of gearing and the Prius engine size and use of the atkinson cycle. It would take a diesel to be more efficient at more "normal" high speeds.

    But the problem is that then you're sacrificing mileage for all the other times.

    Some people just can't handle the truth.
     
  18. dogfriend

    dogfriend Human - Animal Hybrid

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    Are you envisioning an external slingshot apparatus to accelerate it up to highway speed? :madgrin:
     
  19. cwerdna

    cwerdna Senior Member

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    He should then come back w/vehicles that get better mileage at 80 mph than a Prius (or ones comparable in size, weight and hp or HSD equipped ones).

    You should also point him to http://priuschat.com/forums/other-c...eage-no-its-your-gallonage-really-counts.html and to quote from http://priuschat.com/forums/gen-iii...mileage-gets-worse-in-winter.html#post1411488
    Another illustration at http://priuschat.com/forums/gen-ii-...hy-drop-in-fuel-efficiency-6.html#post1378284.

    In essence, the people w/inefficient vehicles are the ones (like sub 20 mpg combined full-sized SUVs) who should be caring MOST about getting better mileage via driving habits/techniques, LRR tires, proper tire pressure, etc. Unfortunately, they're least likely to...
     
  20. Dolce_Vita

    Dolce_Vita Member

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    I tested this theory a few weeks back. While the Prius is undoubtedly super efficient in traffic etc, at about 40-50mph i find it little more efficient than a comparable ICE powered car. I know a country road with a 50mph limit, i often drive on it so i tested the Prius' economy (calculated) and achieved 52.3 over the 10 mile road at a constant 50mph. One thing i find about the Prius is that when the ICE is running, it's not particularly efficient, it seems as if the efficiency comes from being about to cycle the ICE on and off at will. But at 50mph it looses this ability.

    I drove the same route in a 1.4 ICE 77hp Fiat Punto, in 5th gear the whole way, changing to 4th for one hill and not revving harder than 4000rpm the whole trip. Both cars with the aircon off. i Achieved a calculated 51.8 mpg figure - barely worse than the Prius.

    I've also done this trip in a 180hp lightly tuned 1.4 turbo Fiat Bravo, in 6th most of the way, and got a still decent 46mpg figure from it.

    This makes me think that at some speeds a Prius isnt that efficient in comparison to current non-hybrid 4 cylinders (VW's new 1.4 that's capable of 53mpg sounds interesting, as does the 60mpg Fiat Twinair) at certain speeds. That said, you cant beat a Prius in traffic/urban areas unless you go for a Fiesta/Polo eco model which would barely match a Prius in urban driving.
     
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