Jerry Hey wrote:
[Windows Computer] Arrived yesterday and is working well.
> I put a zip drive on it and
another one on the Mac so that I can transfer files back and forth.
I downloaded two free programs sketchup and abword and moved them to
the pc no problem. I can't believe how clumsy Windows is but it does
not matter once I get where I want to go.
I downloaded the PicAxe PDFs and printed them out. Have not had a
chance to go further. I will be laid up in early January (knee
surgery) so I hope to move forward on this project then.
Jerry
Great Jerry. USB flash drives also work well for transferring files
on my Linux system.
I am just looking at the PicAXE manual and PicAXE BASIC manual pdf's
and trying to decide which command to use as a hardware interrupt.
Looks like the SETINT command is it. See the attached files.
Then you do the main program that reads the MAP or
mass air flow sensor and sets the fuel pump PWM based
on the mixture look up table. You also have to read the leaning
pot on the instrument panel. Then your done and you go back
to the back ground loop.
This happens when the ign trigger pulse comes in every time the rotor
turns
once. Assuming we are using one EFI system per rotor. I think the PWM on
the fuel pump is a simpler and cheaper system than one on each injector.
Of course there are no injectors or pressure regulators to buy. This
system keeps looking cheaper and better.
BTW I am going to use the Stock Mazda 2nd gen mass airflow sensor
pictured
as it is very cheap and readily available as a lot of people
have them lying around. I have two. People get one with most engines.
The other subtle advantage is you don't need a MAP and a hand vacuum
pump to test the system on the bench. You just move the spring loaded
trap door
by hand. Perry Mick has been flying with one for years. Not really big
enough for a P-port but some US 250 HP or above V8 mass air flow sensor
can be added later.
I just had an idea that tiny steel or copper tubing could be used
to go into the mouth of the runners and can be as long as
you want. You could inject the fuel anywhere along the length
of the runner right up to the P-port. I'll do a 3D shortly.
No tig welding injector holders to the runners required.
My purely mechanical low pressure fuel injection is only waiting on
the needles to be ground. Should be done by the first of the year
so that will be tested on the dyno first. Then I'll test this
system if it works on the bench.
I think there is a market for both.
---------------------------------------------------------------
I just noticed a skematic error in the voltage supplied to the mass
air flow
sensor. Should be 5 volts instead of 12. There are some small, cheap,
3 pin 5 volt regulators out there that will work for this.
BTW if you wire a leaning pot in series with the mass airflow
sensor pot you don't need to read the leaning pot with an A to D
in the PicAXE. The leaning pot merely modifies the voltage
coming from this mass air flow sensor. That further simplifies the
software and saves one A to D required in the PicAXE.
Also I notice this mass airflow sensor has a fuel pump switch
built in. No fuel unless there is some air entering the mass air
flow sensor. Nice feature to help prevent prevent flooding.
Very important on an RX8 engine. There is one other sensor
in there that I have not figured out what it does yet.
Perry Mick probably knows what it does.
Paul Lamar ...No rotor no motor.
Sorry, I'm behind on email and just saw this. I do not use the switch in
the airflow sensor to control fuel pumps. I have two fuel pumps and both
are enabled by circuit breakers directly. Also, the extra sensor in the
airflow sensor module is an intake air temperature sensor.
I have never flooded the rotary in my LEZ in almost 700 hours of flying,
probably because I shut it down by turning off both fuel pumps. This
procedure de-pressurizes the fuel rails during the time the plane is
parked between flights, so no possible leakage from the injectors into
the engine.
Perry
Well it does not have a side exhaust port either. I flooded my RX8 engine
when I first got it and it is nearly impossible to get it started
without sucking all the RAW fuel out of the bottom of the rotor housings
using a small hose through the lower spark plug hole.
With a P-port RX8 on the other hand it should be possible to tilt the engine
slightly and force the raw fuel back out the intake manifold.
Paul Lamar ...No rotor no motor.
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