The attachments are those you sent on 11/18/2009.

I'm working on my own engine control and some questions arose as I
referred to the attached data.
The pressure tap data from Rotor 1 and Rotor 2 do not appear 180 degrees
out of phase, and the phase difference varies with rpm. Could this be
from different lengths between the two lines from ports to sensors?
In the photo "Apex-oil-hole-data.jpg",  the sensor plotted by the yellow
line appears to be saturating at 4.1 volts. Is that sensor in the apex
oil hole, or is it in the intake ports?

It would appear that in order to prevent pressure waves from saturating
the sensor, it needs either to have a range considerably above one
atmosphere or the volume of the line from the pressure tap to the sensor
needs to be high enough to damp out the variations and provide an
average pressure.

What model sensor is used to provide the red and blue plots?
Just an observation, but it would seem that the peak pressure at the
location you are recommending for the pressure tap should be a valid
indicator of the air charge. In order to have a volumetric efficiency of
120%, it would seem that the pressure would have to reach 120% of
ambient, and would be seen by the sensor connected there. If so, then
the MAP sensor peak output would account for VE, or be closely
proportional to it. An op amp configured to output the highest voltage
applied to it could then be used to provide an output proportional to
air charge.


Victor Roberts

In the photo Apex-oil-hole-data.jpg The yellow line is the CAS signal.
That is just the timing reference to 20 degrees BTDC.

We damp the pressure variations from the apex sealing
oil hole with a tiny hole in the pressure tap fitting.

That is a Free Scale pressure sensor. The 120% VE has
been verified on the dyno.

This engine was not generating full power as it had
a fixed pitch prop. It would not see full power until
the prop tips ran into the sonic wall and with the
throttle wide open and then only if the engine
happened to be generating peak torque at that RPM.

What ever pressure one reads there just needs to
be consistent and repeatable as the mixture is adjusted
in software for whatever power that measurement
represents. In other words it may not  represent
the average mass of air going into the engine. It may
not be the average manifold pressure.
Whatever it is it works very well with Tracy's
EFI system as the engine runs smoothly through out
the rev range.

Our intention  here was to study the organ pipe
tuning effect. Most of the pressure measurements were
made in the wall of the runner close to the rotor housing
for this  purpose. The response of the pressure sensors
is only rated at one milli second. We were sampling at
the rate of 1000 samples per second.

Any phase discrepancy could be due to the data acq system as it does
only one pressure measurement at a time and that may take as long
as .1 ms second or 100 micro seconds or longer because the data must
be sent to the notebook computer serially.

However we are the world wide leaders in this technology
as I know of no other organization doing this kind of applied
R&D. If they are doing it they are not publishing it to
my knowledge.

Necessity was the mother of invention in this case.

Paul Lamar


Paul,

Do the brass oil injectors [nozzles] have any type of
one way valve in them or are they simply a shaped nozzle?
I have been trying to take them out without any luck.


Doug in Japan


Are you talking about the brass orifice (jet) in the bottom
of the 10 mm  threaded hole? I would leave then in there
and make sure they are not plugged up.

The oil nozzles have one way valves and we looked into
using them. It is just not practical. The way they work is
the pressure on the rotor housing side is below atmospheric
so they automatically suck apex seal oil in assisted by
the air flowing in the one way valve. The apex oil metering
pump is not pumping anything. It merely presents
oil to the oil nozzles at atmospheric pressure.

The one way valve prevents oil flowing out the the
air tubes that are connected to the intake system
beyond the throttle down stream of the air filter.
The oil nozzles do the injecting. Actually when
you fully understand this you realize the oil nozzles
are not the best for continuous high power. OK for cars.
In that case it is much much better to mix the apex seal
cooling oil with the fuel IMHO. More fuel more power
more apex seal oil.


Paul Lamar