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Elio Engine Block

Discussion in 'Elio Drivetrain' started by harlan stephens, Oct 9, 2014.

  1. CrimsonEclipse

    CrimsonEclipse Elio Addict

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    The longer stroke has a very specific application on the Elio
    Gonna be a bit long winded, but work with me here.

    I need to start with the aerodynamics (I'll get to the point, I promise)
    The Elio has roughly half the drag of the 1996 Geo Metro (5 speed manual 1.0 3 cyl), a car that is commonly used for comparison.
    This is very important.

    Let's Say:
    Elio at 30 mph has 1 unit of drag
    Geo Metro at 30 mph has 2 units of drag

    The units are unimportant for this argument, measure them in lb or kg of resistance if you will.
    Double your speed and the drag increases by 4 fold (use the K = ½mv2 if you must)

    Elio at 60 mph has 4 units of drag
    Geo Metro at 60 mph has 8 units of drag

    So an engine designed to be efficient in a Geo Metro at 60 mph (with a specific gearing, and stroke) would actually be LESS efficient in an Elio
    (measured in thermal efficiency)

    This is where the length of the stroke of the piston comes into play.

    Definitions:
    Torque: power per impulse
    Horse Power (Watts or Kilo Watts): Power per impulse multiplied by rate of impulses (RPM is a factor here)

    A short stroke engine will produce less work per impulse but typically make an engine that allows a higher RPM with the same technology.
    The power curve will show less HP at the lower RPM's but, due to the higher RPM, it will produce more HP at the high end.

    A long stroke engine will produce more power at lower RPM's helping acceleration but be limited on the high RPM's thus limited on the rated HP.

    Most drivers rarely make maximum horsepower which is measured at best rate RPM AND open throttle.

    This brings me back to aerodynamics.
    The Elio aerodynamics require less work to be done at speed. This allows a longer stroke engine to provide good acceleration without the NEED to have additional HP at the higher end. Thus 55 HP may seem paltry, it's actually sufficient due to the power curve of the long stroke engine.

    This would actually explain the drop from 65 HP to 55 HP during the development of the engine.

    Keeping this in mind, it is likely that the Elio will actually be "peppy" and fun to drive opposed to the sluggish nature of the Geo and more modern Prius C

    Stay tuned for our next lesson:
    A longer stroke does not necessarily mean a higher compression ratio.
     
    Johnapool, Jelio, Elio Amazed and 5 others like this.
  2. skygazer6033

    skygazer6033 Elio Addict

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    55 HP paltry? Back in about 1980 I built a car that only had 19 HP. The car weighed a little over 1400 lbs. and got 70 -75 mpg and could hit 65 - 70 mph on level ground. A little weak on the 0 to 60 times but driveable. The best part was being able to drive to work 6 weeks on a tank of diesel. Torque is far more important than HP.
     
  3. CrimsonEclipse

    CrimsonEclipse Elio Addict

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    Many see the HP rating as the end all and be all and sneer at smaller numbers
    Assuming 1250lb and 55 hp, the Elio comes in at 22.72lb/hp
    And according to this:
    http://en.wikipedia.org/wiki/Power-to-weight_ratio
    Is about the same as a Ford Focus 2.0L

    Frankly.... not bad for an economy car..
     
  4. Smitty901

    Smitty901 Elio Addict

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    Torque moves my 1100 pound HD loaded down up the mountains operating at 2000-3500 rpm most of the time.
    HP sets the 1/4 mile speed record.
    All I need to the ELIO to do is get up to traffic speed at a rate better than the peddle car and hold Highway speeds.
     
    Jelio, goofyone and harlan stephens like this.
  5. harlan stephens

    harlan stephens Elio Addict

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    Torque is key in this little motor for sure.
    And most daily drivers.

    Salt flats....Ill take hp ;)
     
    goofyone likes this.
  6. WE7X

    WE7X New Member

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    Some time ago, after seeing a picture of the basic shape and design, I asked the teck folks at Elio if this 3 cylinder motor was related to the Suziki car motor, also used int the GEO Metro if I am correct.
    The basic response I got was that it was that it was 'based' upon that motor. Obviously a fair amount of rework and modernization, but the basic bones seem to be from that motor. It was a reliable motor and produced great fuel economy in it's day, and ones in good condition are still seen on the roads with a lot of economical miles on them.
    Rod J
    Issaquah, WA
     
    Jelio, goofyone, outsydthebox and 2 others like this.
  7. Hog

    Hog Elio Addict

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    Not trying to make any point or draw any conclusions. Just trying to understand the IAV connection, since IAV openly advertises - " We provide our clients with production-ready solutions for the entire vehicle." - They do not build production engines, they do the R&D so someone else can build them. I am asking who is going to actually be producing the engines after IAV is done with design and testing?.
     
    harlan stephens likes this.
  8. goofyone

    goofyone Moderator Staff Member Moderator

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    Once IAV is done testing and clears the engine for production Elio Motors will be machining and assembling the engines themselves in the Shreveport plant. I am sure they will receive support in this process from IAV and Comau engineers.

    Elio Motors will likely use a commercial foundry to provide the raw castings. The prototype engine castings have been produced by Grainger & Worral. We have not yet been told who will produce the production castings.

    http://us6.campaign-archive1.com/?u=24b371802c83d81776b06aa68&id=c1dea37f20
     
    Last edited: Oct 13, 2014
  9. wheaters

    wheaters Elio Addict

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    It is!

    All other things being equal, the torque increase on a long stroke engine comes from the larger "throw" of the crankshaft, giving a longer lever arm for the piston to act upon. The downside is that it won't rev so high as a short stroke engine of the same cubic capacity.

    The closer we get to the diesel engine (long stroke + high compression + tall gearing + wider open throttle + low engine RPM), the more efficient the engine will be. This is how Suzuki got 55 to 60 mpg from G10 engine fitted to the Geo Metro / Suzuki Swift over 20 years ago.. Elio are going further still (literally) with lighter vehicle weight, better aerodynamics, less tyre drag, all of which allow taller gear ratios, resulting in excellent mpg..
     
  10. ehwatt

    ehwatt Elio Addict

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    You are a clever bloke. I always thought torque is for the real world, horsepower for race tracks.

    Back from under dust and cobwebs, I seem to recall that torque x rpm / 5252= hp (SAE).
     
    outsydthebox and harlan stephens like this.

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