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Good Evening, Folks
Here is a teaser for the DIE presentation to be given at Shady Bend. In
it, I calculate the intake pressure increase that the DIE gives you in
order to show what you might get (power wise) at around 5700-6000 rpm.
The slide first shows the derivation of Power for a rotary without DIE
producing approx 140HP (this was the value on the Mazda Power/rpm chart for
the 1988 NA 13b). I chose a Ve of 0.85 and an Air/Fuel ratio of 13:1. in
order to have the engine generate 141 HP at 5640 rpm Both I think are
reasonable values for the automobile none-DIE 13B.
These figures calculated out to 141 HP and some change, but that was just to
establish a baseline 141 HP which is the HP of the engine Mazda used for
comparison with the DIE 13B.
The next section (Pt=Po+1/2pV^2) is where I determine how much total
pressure the Pulse generates when it slams into the port at the other end of
the tube. Impressive amount as predicted by the Finite-Amplitude Theory, in
fact - if you had that pressure continous (like a turbo charger etc) the
1.87:1 pressure ratio resulting from the pulse would have the engine
producing approx 264HP!
But, Alas, the DIE effect is of very short duration, however it does produce
a significant increase in HP despite its short duration. Since it is not
continous - then how to calculate its part of power contribution? I show my
approach in the DIE POWER CALCULATION section.
Well I figured if DIE were continous then it would produce the 1.87:1 ratio
the entire time the intake port is open - all 308 Deg Duration (secondary
port + auxillary port combined duration). However, as mentione above the
effect is NOT continous. The duration of the "A" and "B" pulses of the
DIE combined is approx 23 deg of Eshaft rotation which amounts to about 7.7%
of the total duration. Therefore taking 7.7% of the 264HP that would have
been produce by the full duration at the 1.87 pressure ratio, the
calculation shows that
the power would be increased from the original 141 HP on the none-DIE engine
to 161 HP on the DIE equipped engine -about a 20HP increase.
I attached the Mazda torque/Hp curve chart showing just about the exact
same amont of power increase on the actual DIE equipped engine (solid lines
on the chart, dashed lines are the none-DIE engine performance curves). So
close it's sort of scary.
So, needless to say I was fairly please by the close correlation. So that
is an example of what Mazda says DIE can do and my calculations indicates
that as well.
Of course, that slide does not tell you anything about the inner workings of
the DIE, come to Shady Bend if you get the chance. The rest will have to
wait a tad bit longer. I did say it was a teaser!
Best Regards
Ed Anderson
That is
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
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