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Automotive Alternative engines for a car?

  1. Mar 30, 2014 #1
    a friend and i have been discussing taking what we know (mostly what i know) in the field of mechanical engineering and designing and building a car.. it will be my car, but he's willing to help with it

    the body style of this car might look something like a cross between a corvette/viper and something from the 30s or 40s.. morgan aeros have a similar look for comparison

    anyway, i was looking at some less than common ideas for engines, including the axial engine design which uses parallel cylinders arranged in a circle around the shaft, using a swash plate to convert reciprocating motion into rotational

    another idea i was considering is the tesla turbine, however, such an engine hasnt really been used before in a larger application and im not sure if combusting fuel inside the intake of this engine would even work.. so i had the idea of using a tesla turbine as a steam turbine to convert pressurized steam into energy.. and since most modern tesla turbine designs utilize carbon fiber discs, the overall weight of the turbine would be very light, and a captive steam system with a flash boiler could be compact enough and efficient enough to work with overall very few moving parts in the final design.. the turbine blades attached to the central shaft and a valve for changing water flow into the flash boiler would really be the only moving parts

    also, i was thinking of adding an electric all wheel drive system in which hub or pancake motors (more than lightly use some smaller, lighter weight motors and a gear behind each wheel as hub motors dont seem to offer much speed) and a generator attached to the engine.. if the steam/turbine system works and i use that then likely id add a very, very small battery pack to act as a buffer for more immediate throttle changes that steam and turbines dont really offer

    so i was wondering if anyone had any other ideas i could begin working on at least in small scale to come up with some sort of a unique drivetrain for this vehicle
  2. jcsd
  3. Mar 30, 2014 #2


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    Is all this stuff supposed to fall off the back of a truck somewhere, or do you have independent financial resources?

    It's one thing to daydream. It's quite another thing entirely to realize these dreams.
  4. Mar 30, 2014 #3
    its my own financing.. most the cost is going to be in the drivetrain.. backup plan of course is to just go with a conventional, likely V-8 engine, but im looking for alternative ideas that may be worth consideration.. i like the idea of the axial engine but it seems like such an engine would lead to higher levels of vibration as the cylinders tend to fire in a circle.. and as for the steam/turbine idea.. that poses a whole new set of questions that are pretty hard to answer without a full-scale test of the components
  5. Mar 31, 2014 #4
    For a Tesla turbine to deliver good efficiency, it needs to rotate with very high rpm... for which reason turbines are good as jet engines, where we have long operation at cruising speeds. Versus a car engine, which is an on-and-off kind of thing.

    Unusual engine? A compressed air car would be very interesting... or one powered by liquid nitrogen. These 2 "fuels" have lower energy density than gasoline, but are an interesting concept :smile: All the best with your project!
  6. Mar 31, 2014 #5
    An elastic band?
    An alternative engine? To what end? For what reason?

    There is a reason why a piston engine has been used in the car pretty much since it's inception, it's because it's the best tool for the job. The only obvious competitor is electric.

    If the objective is to have a car that works, then just put in a real engine and have done. If it's for novelty, then do whatever you want.

    Also, radial engines have very good vibration characteristics. Short crankshaft, balanced and generally pretty smooth running.
  7. Mar 31, 2014 #6
    longevity doesnt necessarily mean its the best tool for the job.. it means it offers the best profit margin for the job, usually it means little more than that

    anyway.. im aware of the downside to steam and turbine technology, both these technologies tend to work best when they can be maintained at a specific speed and neither engine fares well for stop and go, or in situations where you need on the fly changes in speed.. thats why i proposed using a small battery bank as a buffer, so the engines store the battery.. like a hybrid which would allow instant startup and rapid changes in speed while the engine itself remains at a constant

    the idea im most focused on to this point is the axial engine though
  8. Mar 31, 2014 #7


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    Batteries are less than ideal buffers, because they charge and discharge less than optimally.
    A flywheel might be a better bet, although there too the power transfer in and out is no picnic.
    The late William Lear of Learjet fame worked hard on a steam engine design which might have potential.
    Harold Rosen, the man who made geostationary satellites a reality, later developed an innovative hybrid gas turbine cum electric automotive engine.
    If you have the talent and the money, those are avenues where a lot of problems have been resolved, but where more work is still needed..
  9. Mar 31, 2014 #8
    thats interesting, ill look into those things.. axial engines are fairly straightforward.. doesnt seem like theres much more than can be done to them.. so ill focus more time on the steam and turbine avenues
  10. Apr 1, 2014 #9
    anyone familiar with the concept of a 5 stroke piston?.. exhaust gets pushed from two pistons into a single, larger piston, expanding that cylinder, and then on the up-stroke the exhaust is pushed from that piston out of the engine.. it uses the leftover pressure from the exhaust.. you know, the stuff powerful enough to spin a turbine to compress incoming air (turbochargers).. but instead the engine uses that extra, often wasted energy for greater fuel economy and more power
    Last edited: Apr 1, 2014
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