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Compressed air car

  1. Dec 31, 2009 #1
    hi there,
    i am studying the feasibility of compressed air to power a car as my final year project and i need some guidance.

    How i proceeded:
    (1) I derived equations for the driving force and consequently for the road-load power of a car, with speed as the variable.
    (2) I worked backwards using data about power losses in engine and in car transmission which i assumed to be almost constant. I tabulated the indicated power and indicated mean effective pressure inside the cylinder required at different speed
    (3) I then calculated the inlet pressures of compressed air required at different cut-off ratio and at different speed if the engine was to operate as a reciprocating piston air motor with 4 cyl in line such that when two pistons are doing the power stroke, the other two are performing the exhaust stroke.

    My questions are :
    1.Can a conventional car engine be used as a reciprocating air motor, that is, with the same piston-cylinder assembly, piston rings, connecting rod, crankshaft?
    2.What about the valves?
     
  2. jcsd
  3. Dec 31, 2009 #2
    Oh no not again.
    We already have a compressed air car thread, although little out of it may be useful to you since it seemed to verge on perpetual motion at times.
    https://www.physicsforums.com/showthread.php?t=310462

    To answer what I can.

    1. Yes with extensive modifications. May not be worth it to you, since the cost of modifying is probably more expensive than an off the shelf air motor.

    2. Complete rework on the valves/camshaft. A regular internal combustion engine has valve strokes that are very different from an air motor. You have to get rid of the compression phase.

    Your best bet may be to use a 2 stroke diesel modified for bash valves. These have been used for steam powered setups, but should work just fine with compressed air. Or alternatively you could use existing air motors and avoid the hassle entirely.

    One of these on each wheel and I think you would be in buisness.

    http://www.grainger.com/Grainger/items/5KB10?Pid=search [Broken]
     
    Last edited by a moderator: May 4, 2017
  4. Jan 6, 2010 #3
     
  5. Jan 7, 2010 #4
    nishat,

    Google "MiniCAT" for all the information you would care for about compressed air motoring.
     
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