Re: Rotary Pulse Jet Engine; Discussion on air car
- 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)
- On 9/12/07 3:22 AM, uthave wrote:
> The compressed air car is a much desired development in the searchThe reports I'd previously read on it cited an abnormally high dB level --
> for an alternative cleaner, non-polluting form of motivating power
> that can be used in transportation.
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.
- [Default] On Wed, 12 Sep 2007 09:20:14 -0500, Linda
>On 9/12/07 3:22 AM, uthave wrote:Good point. The quietness of the EVs I have been in has been very
>> 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.
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
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.
- 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
--- 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.
- --- In firstname.lastname@example.org, Eddie
>A lot depends on the the frequency of noise being produced, if the
> 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
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
> Completely in favor of cars that do not need gas, waiting for onemyself,
> but am vigilant to this kind of thing, because opponents anddetractors work
> hard to find any little chink to try to tear down these new ideas.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
- On 9/15/07 2:19 AM, uthave wrote:
> Maybe I thought I was beingI'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.