There are at least two optional wiring schemes for the one PicAXE
per injector EFI system.

The PicAXE could be mounted on the injector
or it could be plugged into a mother board bus located
behind the instrument panel. That would give you the option
of using one mass air flow sensor to cut about $30 each
from the PicAXE parts cost. It would also reduce a bunch
of wires floating around the engine compartment. The leaning
pot could be attached to the motor board. So too the
USB connector for the removable cockpit PC.

What do you people think ?

Here too is the Omega temperature data acquisition RS232 net work
system for the addition of EGT and other temperatures monitors.
Of course they will require one off the shelf low cost RS232 to
USB adapter as will the RS232 PicAXE's. This adapter can be mounted
on the mother board. Data display and formating is up to the PC.
-- 
Paul Lamar ...No rotor no motor.

Hi Paul,
The motherboard bus offers fewer wires cris-crossing the engine and
therefore less opportunity for wire damage and stray electrical noise
pickup. Also trouble shooting will be easier with only two wires per
injector to check for activity, if those wires check out then the
motherboard bus could be removed for troubleshooting comfortably at a
bench rather than hanging into an engine bay trying to figure out
exactly which wire is from where when the real problem could be a simple
solder joint failure. Does anyone see advantages to the injector mounted
concept?        Dave M


I agree.

I might add there is another advantage to the bus approach.
A spare PicAXE can be carried and exchanged in the air if one
PicAXE fails assuming you are high enough and have the required time
of course.

I might also add that the RS485 interface system could be implemented.
This is a balanced line, twisted pair interface system with
reduced susceptibility to electrical noise compared to RS232 systems.
There are chips that convert RS232 to RS485.

Paul Lamar ...No rotor no motor.

Paul,

I would vote for on the mother board bus unit. Like Dave mentioned mainly to
cut down on noise and wiring runs.  The unit doesn't HAVE to be the cockpit
per se but it would be a definitely benefit to be in a more benevolent
environment than the hot engine compartment. Yes on easy access location and
the RS 485 communication protocol.

This board is starting to become the size of MegaSquirt's though I
understand the parallel processing and programming advantages.

Doug Fir

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