In addition to the mechanical low pressure fuel injection system
we are doing a PicAXE system. I am trying to find somebody to do
the actual work as I have a limited amount of time to do it myself.
I am talking to a couple of candidates as we speak.

This is a paradigm shift in EFI. One computer per injector instead of
many injectors per one computer. Each tiny computer is designed to do
one thing and one thing only. My rule is software complexity is  proportional
to the square of the number of features or things the computer must  do.

PicAXE computers are super cheap. Spark plugs now use one coil per
plug with built in electronics. Why not one cheap, tiny, $1 computer  per
injector. You can use two injector systems per rotor if you wish.  These
systems will work with 1 to 4 rotor engines.

This is a cheap and simple PicAXE system written in easy to
learn and modify BASIC programming language. The PC sends
English language commands to the PicAXE and the PicAXE
does it.

A pulse is taken from the engine
crank  angle sensor and the computer measures the intake
manifold pressure or mass airflow sensor (A/D) and intake air
temperature and fires (PWM) one injector every time the one rotor
engine rotates once using a mixture look up table. A hardware
interrupt from the crank angle sensor is the easy way while
a do nothing loop runs in the back ground. Max RPM is 7500 or
125 pulses per second or once every 8 msec. Should be enough time
to do the simple job.

I'll gladly trade off computer speed and software simplicity for
hardware. No compiling and no chip burning. We want to keep
it as simple as possible so people with no experience in
programming or computer hardware can program it, understand it
and fix it. We also gain redundancy for safety reasons.

The injector computer will get inputs from a manifold pressure  sensor, or
a mass airflow sensor and an ignition pulse. All these sensors are  capable
of supplying data to more than one computer simultaneously. It is a
massive trade off of additional cheap hardware for much simpler  software.

Ultimately it is designed to be used with a new generation
of small PC's in the cockpit that use flash RAM instead of hard  drives.
Unlike hard drives flash ram is very rugged and works at high  altitudes.

What we will do long term is use several of these real simple systems
and have them talk to one small PC in the cockpit over a simple  RS232 serial
network. The PC sends out an address and the PicAXE injector with that
address responds with data. There are other data gathering modules
from www.Omega.com that work the same way. Many mixture maps
can be stored in the PC and sent to the PicAXE injector computer.

When we get one working will will build another and test it on
an actual engine on the dyno.

Here is a project I did years ago using a 6502. I was also the
designer of the Superkim and the sole owner of Microproducts.

Microprocessor-Based System for Roll-Down and Acceleration Tests
by D.K. Lynn, C.R. Derouin, and Paul Lamar
Los Alamos Scientific Laboratory
Published in IEEE Proceedings 29th Vehicular Technology Conference
(The technical details of the Lamar Instruments road test system.)
Arlington, Illinois, March 28-30, 1979


The most user friendly suppler of PicAXE parts and prototype boards
is http://world-educational-services.net/
You can actually call them and talk to a real person.
Phone:410-255-6333  The product I am buying is the AXE090 - Exper.  Board

PH Anderson comes up first if you google PicAXE but it is very  frustrating
doing biz with him. He does not return emails and he does not
answer his home phone let alone the fact there is no phone number
on his web site. I don't do PayPal.


Paul Lamar ...No rotor no motor.

Paul,  I am your guy with no experience with hardware or   programming.  And I would like to learn.  Can you suggest a text to  introduce me to this strange  world.  If I can learn it, anybody  can.  How do I begin?   The local community collage has some  courses, I will pick up the course catalogue tomorrow and see if any  would be of use.    Jerry

Sorry Jerry you are too late. I just hired a guy. However we will
be writing articles for the newsletter from time to time on our
progress with pictures so you can follow along.

In order to do exactly what we are going to do you will need
a AXE090 - Exper. Board. It comes with almost everything you will need
terms of the computer.

First get a cheap proto. PC boards from Radio Shack
and a handful of cheap 1/4 watt resisters and practice soldering.
DigiKey or Mouser has cheaper parts than Radio Shack. You will also
need a small pencil soldering iron around 20 to 50 watts.

You will need a high pressure fuel pump, an fuel injector of some kind,
and an injector transistor or two as well as a MAP sensor. You will also need
a hand vacuum pump from the auto parts store. I'll let you know the
part numbers later. You will also have to build a 555 oscillator.
The 555 oscillator is going to simulate the ignition trigger
pulse when on the bench.

If you don't know what these things are google will help.
An old used book on Quick BASIC programming will help. (Ebay)
You will also need a PC as a Mac won't work.
An oscilloscope would be handy but not mandatory.
A cheap  VOM with a frequency counter would also help.

Paul Lamar

Jerry,
If  you want to build experimental electronics stuff, life will be much
better with a temperature controlled soldering iron similar to this one:

http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=11889

Use solder that is 0.032" diameter or smaller.  Also, an impulse type
"solder sucker" similar to one of these is very useful for changing
components:

http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=12262

Don't buy a metal one.  The plastic ones have less inertia and work much
better.

Mouser Electronics has, apparently, been purchased by a conglomerate and
is no longer as good a parts source for electronic experimenters as it
once was;  same situation for MCM Electronics.    Some other
possibilities  for components and supplies are:  All Electronics
(www.allelectronics.com),  and Hosfelt Electronics (www.hosfelt.com).

Aubrey Thompson


The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2007 All world wide rights reserved.