Conference terri::cars_uk

801.0. "A "new" type of IC engine" by GIDDAY::GILLINGS (Have we fixed it yet?) Mon Oct 16 1989 12:34

    I saw a TV report about a guy with a "new" kind of internal combustion
    engine which "has the potential to change the face of the world" you
    know the stuff, less pollution from a smaller, lighter, more powerful,
    more fuel efficient motor etc... In Oz we've seen this all before with
    Ralph Sarich who has only just announced a contract with Ford US to use
    one of his engines nearly 20 years after he first demonstrated his orbital
    engine (besides the Ford deal is for an improved 2 stroke engine, not
    the wonderous orbital). The Wankle engine has enjoyed some attention but,
    overall, I think it's been a bit of a failure.
      Anyway, this new engine looked rather interesting. As demonstrated, the
    engine consisted of a central shaft with a "swash plate" at either end
    (a swash plate is a disk attached to the shaft at an angle so that a
    point on the plate moves along the axis of the shaft as it rotates) In
    the middle were 2 cylinders each holding 2 opposing pistons. The pistons
    have fixed con rods which touch the swash plates. As the piston moves
    out, the conrod causes the swash plate to rotate, thereby converting
    linear motion into rotational motion without a crankshaft. Further
    rotation of the swash plate pushes the piston back in.
    
    		   cylinder
                  ----------------
           /------------|  |------------\          pistons in compression
          /       ----------------       \
         /                                \
    ----/----------------------------------\-----  shaft
       /                                    \
      /           ----------------           \
     /------------|              |------------\    at end of power stroke
    		  ----------------
    
      Now the clever bit. The inventor claims that conventional engines are
    inefficient because the crankshaft dictates that the piston always
    moves up and down in sinusoidal motion, in particular the length (and
    time) of the compression stroke must be the same as for the power
    stroke. He says the compression stroke should be slower and the power
    stroke faster (to match the combustion characteristics of the fuel/air
    mixture). So, his swash plate isn't flat, it has kinks and flat spots
    on it so he has full control over the motion of the piston. In a
    conventional engine a displacement/time graph of the piston is a sine
    wave. In this guys' engine it would look like a sawtooth with a small flat
    spot:
                             ---
                          ---   \
                       ---       \ 
                    ---           \
                 ---               \
              ---                   \
    _______---                       \_______
    exhaust  compression	power exhaust
    
    Clearly the engine must be a 2 stroke ('cause the piston only moves out
    on the power stroke and must be pushed back by the swash plate) but they
    didn't give any details of the porting/valves in the cylinder. You can also
    vary the number of cylinders but it seems that 2 is the minimum. As
    with all good inventions it is simple and uses a fairly obvious mechanism.
    Just a few questions for the net though -
     
      1) The idea of a swash plate seems very familiar to me, has anyone else
    	 heard of a similar crankless engine? If so did it use a uniform
    	 plate (=sinusoidal motion)?
    
      2) Is it possible to tune the plate for optimum combustion or would
    	 it be necessary to keep the engine in a narrow rev range for 
    	 reasonable performance? (bring on the infinite ratio gearboxes?) 
    
      3) One of the inventors' criticisms of conventional engines was that
    	 they are "inherently unbalanced". Surely his swash plates are much
         more unbalanced?
    
      4) Anyone have any idea how efficient it is to use a swash plate?
    	 it would seem to me that it must lack torque unless the slope
         of the power stroke part was very steep or the revs very high.
    
      5) Anyone like to hazard a guess as to the wear characteristics of
         the piston/conrod/swash plate banging away at each other? Imagine
    	 an accident involving one of these engines in which the swash plate
         broke off. 2 (or more) pistons would be propelled at high speed
    	 along the axis of the engine.
    
    						John Gillings, Sydney CSC

    
    Interesting article in International Business Week for 15/01/90
    on the experimental 2-stroke GM concept car.
    
    Photocopy of article for anybody that mails me with their mailstop.

  re .4:

>    Interesting article in International Business Week for 15/01/90
>    on the experimental 2-stroke GM concept car.

   Would this be a Sarich engine by any chance? Ralph Sarich won an inventors
   award about 20 years ago for his "orbital engine" which was going to "change
   civilisation as we know it". He has since made lots of money without seeming
   to do anything. Over the years the orbital engine has changed into some sort
   of hi tech 2 stroke engine. He recently signed some agreement with GM to use it
   it in production cars. Again this deal was going to revolutionise the car
   industry (more power, less fuel, all the usual hype) and earn Australia
   zillions in foreign earnings. Are the predictions finally going to come true?

						John Gillings, Sydeny CSC  

    
    ....... just a regular 'ornery 'ol 2 stroke!