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Tom, Its really fascinating (to me) the
complexities of what goes on in an intake - especially with the
rotary.
You would be interested in the Mazda Dynamic Effect
Intake (DEI). There those Mazda engineers actually use the large magnitude
pulse created in the intake by the expelling of residue exhaust gas to improve
performance (when as you suggested, it would seem likely that it would hinder
performance). Basically, They send the large magnitude
pulse created by the opening of the intake (and caused by the sudden
bursting out of the exhaust residue into the intake) port of one
rotor though the interconnected intake to the intake of the second rotor.
IF the timing is correct (rpm, porting and runner length are primary factors)
then when the pulse arrives at the second port - it will arrive just as the port
is closing on its compression stroke. Normally approx. 20% of the intake
charge already sucked into the combustion chamber is pushed back out by the
compressing rotor upstroke before the port closes - commonly called
"reversion".
In any case, when this high magnitude pulse arrives
at the other rotor, its dynamic energy translates into a significant increase in
local
manifold pressure. This increase is
sufficient to over come most of the reversion effect (provided the timing is
correct) and therefore you retain approx 15% of the 20% of the charge that would
normally be lost. The Mazda performance charts showed a 15% improvement in
HP at 6000 rpm using this effect.
There are two induction processes that occur and it
can get confusing. There is the macroscopic movement of the airmass caused
by the pressure differential as the ports open and close and there is the Finite
Amplitude Wave (FAW) pulses. The FAW pulse travel at the speed of sound
and while of short duration can produce pressure in the vicinity of 10-15
psi. They occur in both the intake and exhaust. They can either
assist the inflow of air or oppose it (and do both at differing rpms).
This is one reason why so frequently what would appear to be a good intake
design does not work as expected. The FAW pulse interact with each other
and the walls of the intake unlike sound waves and undergo transformations
depending on what they encounter. Its only fairly recently that programs
and home computers have reached the stage that permits their analysis on
anything other than a main frame.
But, while there is no doubt that anything such as
exhaust gas that gets ingested reduces the amount of power producing mixture,
its amazing how the Mazda engineers turned what could have been a detriment into
an asset. But, if you have overlaps of intake and exhaust ports (like the
13B or a PP13B ) you will always have some exhaust gas in the intake at some
rpm.
Ed
----- Original Message -----
Sent: Thursday, February 10, 2005 2:16
AM
Subject: [FlyRotary] Re: P port
intake
That is interesting Ed. Just thinking about it and now it
would seem that the expelled residue would be the first thing that got sucked
back thru a dedicated runner, also having a negative effect. Ed
Anderson <eanderson@carolina.rr.com>
wrote:
Tom,
One reason that Jerry would not want to do that
is that there is overlap between intake and exhaust. That means while
one rotor is trying to suck air in its intake port - the intake port of the
other rotor may be expelling some residue exhaust gas out its intake and
opposing any incoming air. I think the engine would certainly
run but I don't think you would develop best power. Now
it would probably be a different story with the Renesis which by
moving the exhaust ports to the side housings has eliminate the
exhaust/intake overlap.
FWIW
Ed A
----- Original Message -----
Sent: Wednesday, February 09, 2005
8:58 PM
Subject: [FlyRotary] Re: P port
intake
Jerry,
Since only one rotor chamber is drawing fuel/air at any given time,
why would you not feed them both from a single throttle body?
George,
originally I was going to hook up with a piece of hose over the
butted pieces with a couple of hose clamps. That is how I will
attach
the other end at the throttle bodies. But, we have been
considering
welding and also building some type of flange.
Certainly, for starters
I will use the hose and clamp method.
Jerry
On Wednesday, February 9, 2005, at 08:43
PM, George Lendich wrote:
> Jerry,
> Is that a but
weld, OR does the tube go into the bellmouth end OR a
> flange that they both go into.
> George ( down
under)
>
> ----- Original Message -----
> From:
Jerry Hey
> To: Rotary motors in aircraft
> Sent: Thursday,
February 10, 2005 9:35 AM
> Subject: [FlyRotary] Re: P port
intake
>
> Yes, it is 1.61 inches.
>
>
>
On Wednesday, February 9, 2005, at 05:39 PM, Tom wrote:
>
>
Jerry,
> Do you have an i.d. measurement for the narrow
end?
>
> TIA
> Tom
>
> Jerry Hey
wrote:
>
> Today UPS brought the
bell mouths for the P port intake. They are
> three inches o.d.
across and have a smooth gradual taper down to the
> runner size
...
>
>
>
>
>
>
>
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