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Re: Rotary Pulse Jet Engine; Discussion on air car

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  • uthave
    The compressed air car is a much desired development in the search for an alternative cleaner, non-polluting form of motivating power that can be used in
    Message 1 of 8 , Sep 12, 2007
      The compressed air car is a much desired development in the search
      for an alternative cleaner, non-polluting form of motivating power
      that can be used in transportation. For the past 150 years the IC
      Piston engine, working on the Otto cycle and first invented in 1866 by
      Nicholaus Otto, has been the mainstay of personal and commercial road
      transport. Yet with all the billions of dollars spent on trying to
      improve the performance of the IC Piston engine, every working
      sequence of the engine being examined and tested with the latest
      computer technology and simulations, by millions of people around the
      world, it is amply clear that if a solution is to be found for a more
      efficient engine, it won't be based on IC piston technology. Even with
      all the 21st. Century innovations and improvements, such as MPFI,
      double overhead cams, multiple exhaust and inlet valves etc., the IC
      piston engine efficiency remains at 20%!
      Think of it, an amazing and unacceptable 80% of the energy in the fuel
      used is wasted, by comparison, rockets and jets have an efficiency of
      70% and better or are more than two and a half times as efficient as
      piston engine cars, they are also, relatively, pollution free.
      Unfortunately, both turbines and rockets require or have required
      until this date, continuous combustion to deliver this order of
      efficiency. When used in road transport they are therefore very fuel
      inefficient using about 8 – 10 times the fuel used by a piston engine
      of similar size.
      The compressed air car comes as a welcome and audacious challenge to
      IC Piston technology, it is an almost viable technology. The
      Compressed air car engine does work, for those of you who have doubts,
      you can check out this link on model airplanes that use compressed CO2
      to run a piston engine. http://blacksheepsquadron.com/index.html
      Of course one has to take into account that CO2 is far denser than air
      and would therefore work better as a compression agent, however the
      point is that the compressed air engine technology is viable, or as I
      had previously stated, almost viable. The reason I say this is that a
      tank of compressed air with a capacity of 340 litres, (taken from the
      MDI Car specifications web-site) the compressed air would last for a
      maximum of 2 minutes. You can perform the calculations for yourself. A
      tank holding 340 litres corresponds to a cube with 2.25 ft sides. This
      tank is filled with compressed air at 4500 psi or 300 bars approx. The
      optimum rpm of the engine is 4500rpm, compressed air engine tend to
      perform best at a given rpm. Now if the cylinder capacity is about 8
      cu ins. then at 4500 rpm, the engine would use 4500/60 = 75 x 8 = 600
      cu ins in one second and 36,000 cu ins in one minute. The capacity of
      the tank is 27 x 27 x 27 cu ins or 19,683 cu ins. But the piston needs
      only about 500 psi to work, so to get an accurate figure we have to
      divide 36,000/9 = 4000. So the tank will last for 19,683/4000 = 5
      minutes approx. The point is that it often takes five minutes just to
      get the car out of the garage also once you use all that compressed
      air there is no way to re-charge the compressed air, so after about 4
      –5 minutes you have to go to a service station and recharge. To
      recharge air at 4500 psi takes about a compressor working at 500 KW!
      500KW, is enough to supply electricity to a fairly large town. The
      longer range of 200km – 300 km is only achievable when an IC piston
      engine is onboard. Again to recompress the air with an onboard motor
      would take at least 3 – 4 kours. So while it is a wonderful
      technology, it is far from viable at the moment. The Rotary Pulse Jet
      Engine, has none of these shortcomings and if allowed I will discuss
      it in my next post. D. James (uthave)
    • Linda
      ... The reports I d previously read on it cited an abnormally high dB level -- it s compressed air, after all. We must not forget that noise is a debilitating
      Message 2 of 8 , Sep 12, 2007
        On 9/12/07 3:22 AM, uthave wrote:

        > The compressed air car is a much desired development in the search
        > for an alternative cleaner, non-polluting form of motivating power
        > that can be used in transportation.

        The reports I'd previously read on it cited an abnormally high dB level --
        it's compressed air, after all.

        We must not forget that noise is a debilitating form of pollution as well.
        We should also be careful of the words "non" polluting. For example, the air
        is compressed using some form of energy, which cannot necessarily be
        guaranteed to be non-polluting, right? Perhaps a more accurate descriptor
        would be to include the qualifier, "at the tailpipe" or some such.

        Completely in favor of cars that do not need gas, waiting for one myself,
        but am vigilant to this kind of thing, because opponents and detractors work
        hard to find any little chink to try to tear down these new ideas.

        peace,
        Linda
      • uthave
        Hi babe! Where u living? It s possible to reduce the noise to zero, using frequencies. Right!!! uthave
        Message 3 of 8 , Sep 12, 2007
          Hi babe! Where u living? It's possible to reduce the noise to zero,
          using frequencies. Right!!! uthave
        • murdoch
          [Default] On Wed, 12 Sep 2007 09:20:14 -0500, Linda ... Good point. The quietness of the EVs I have been in has been very noticeable (with one exception,
          Message 4 of 8 , Sep 12, 2007
            [Default] On Wed, 12 Sep 2007 09:20:14 -0500, Linda
            <saveearth@...> wrote:

            >On 9/12/07 3:22 AM, uthave wrote:
            >
            >> The compressed air car is a much desired development in the search
            >> for an alternative cleaner, non-polluting form of motivating power
            >> that can be used in transportation.
            >
            >The reports I'd previously read on it cited an abnormally high dB level --
            >it's compressed air, after all.
            >
            >We must not forget that noise is a debilitating form of pollution as well.

            Good point. The quietness of the EVs I have been in has been very
            noticeable (with one exception, which was very loud). I have always
            thought that the "EV Smile" we hear so much about, and the regrets
            about getting back into an internal combustion engine vehicle, are
            attributable in part to the lack of noise, vibration and harshness
            that is arguably an advantage an EV might have over an IC engine
            vehicle.

            I have not previously heard of noise being a problem with compressed
            air vehicles, but I've never had the chance to try one, to see.
          • Eddie
            I ve been hearing this claim for years, but no one has deployed a stationary solution, much less a mobile one. Can you site a production example of this noise
            Message 5 of 8 , Sep 12, 2007
              I've been hearing this claim for years, but no one has deployed a
              stationary solution, much less a mobile one. Can you site a
              production example of this noise reduction technology, other than
              headphones?

              --- uthave <uthave@...> wrote:

              > Hi babe! Where u living? It's possible to reduce the noise to zero,
              > using frequencies. Right!!! uthave


              ---
              Is Th!nk on the move? http://www.think.no/



              ____________________________________________________________________________________
              Pinpoint customers who are looking for what you sell.
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            • uthave
              ... A lot depends on the the frequency of noise being produced, if the engine hovers around a single frequency rather than being spread out over a wide number
              Message 6 of 8 , Sep 14, 2007
                --- In future-fuels-and-vehicles@yahoogroups.com, Eddie
                <eddiecolumbus@...> wrote:
                >
                > I've been hearing this claim for years, but no one has deployed a
                > stationary solution, much less a mobile one. Can you site a
                > production example of this noise reduction technology, other than
                > headphones?
                >
                >Hi Eddie,
                A lot depends on the the frequency of noise being produced, if the
                engine hovers around a single frequency rather than being spread out
                over a wide number of frequencies, it should be eaiser to just cancel
                out using fairly simple technology. I have seen such devices, but
                can't think of a reference right now. uthave
              • uthave
                ... myself, ... detractors work ... Sorry about the tone of my last post! Maybe I thought I was being heckled, I apologise whole heartedly for the rather
                Message 7 of 8 , Sep 15, 2007
                  > Completely in favor of cars that do not need gas, waiting for one
                  myself,
                  > but am vigilant to this kind of thing, because opponents and
                  detractors work
                  > hard to find any little chink to try to tear down these new ideas.
                  >
                  > peace,
                  > Linda
                  >Hi Linda,
                  Sorry about the tone of my last post! Maybe I thought I was being
                  heckled, I apologise whole heartedly for the rather cavalier and light
                  hearted tone of my reply. I am posting the second half of my article
                  on "The Rotary Pulse Jet Engine" at this forum, you might like to have
                  a look at it. uthave
                • Linda
                  ... I m sorry if my reply gave you that impression. I wasn t in any way trying to make light of your post or the information contained therein. My apologies if
                  Message 8 of 8 , Sep 15, 2007
                    On 9/15/07 2:19 AM, uthave wrote:

                    > Maybe I thought I was being
                    > heckled,

                    I'm sorry if my reply gave you that impression. I wasn't in any way trying
                    to make light of your post or the information contained therein. My
                    apologies if it seemed otherwise.

                    ~Linda
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