IGNITION PROJECT

[Mark Pitts]

New question.. might develop into a thread, but I'm hoping to start a =
discussion, and follow the whole design process through to a running =
system.

Objective: Replace the distributor and points with a blob with some =
inteligence.

Desired sensors: Combined engine speed/crank angle, MAP, water temp, =
knock, and possibly air temp.

Desired outputs: 'points' output for as many coils as required. 1,2 or =
4. Cooling fan out put. RS232 monitor port. High speed interface for =
sensor output to possible further extension blocks.


Reasons: My engine is a 4 pot normally aspirated 1.5 liter engine. Its =
distributor is shot, and needs replacing. It eats points, and condensers =
and coils, and no there is no fault, all spitfires do this!

Sensing: Speed and position from a machined chain sprocket bolted to the =
front pulley (which in my case is keyed in one position to the end of =
the crank), with 36 or 24 teeth. Pickup is to be the digital magnetic =
pickup from RS components , it costs 16 UK Pounds or about 35 bucks to =
anybody over there if I have to send them (if you guys cant buy them). =
MAP to be measure using MPX4250A, about 30 bucks (up to 36 psi, so that =
allows turbos up to about 22 psi boost. Knock: haven't even thought =
about this one yet, all suggestions welcome . Water temp, million and =
one ways of doing this.

Processor: 68 something (but only if I'm doing the programming, if you =
want to join, and do the software, I'll adapt to what you like)
On the fly re mapping, in flash.
All information to be made available to other systems on request, by =
serial coms.
High speed programmable pulse chains indicating TDCs, firing points etc =
for accurate timing by other systems (possible fuel inj?) and scope =
diagnostics.
Remote controll of ignition events by other systems (eg, revlimiter, =
traction control etc)

Extra sensor input from current points, to allow initial map to be built =
from currently working mechanical system.

CUT TO THE CHASE:

Order of development:


Sensors first.

Chose sensors, and design their interfaces, then test.
Design software.
Chose uP
Design system.
Test system and refine.

Up shot.. publish the sensors and interfaces , so that other scratch =
builders can just do a building block design on their own hardware. If =
at the point I go 68xx(x) they want to go PC or Z80 or anything else, =
they can, and the software design can be followed and implemented, even =
if they cant use the code.

Things needed imediatly:

Suitable temp sensor, and a knock sensor, and preferably their interface =
schematics if anybody has a suitable solution to these two questions, I =
would dearly like to hear from them.

Does anybody want to join this idea.. or am I on my own for this one?

A good programmer would be a bonus, I can do it, but I would prefer to =
let somebody else do it. I am prepared to add dedicated hardware for =
doing timing, and interrupt control, and stuff like that. Anything that =
makes the programming easier. ;-)

Mark

(Who has decided to stop messing around and get on with it)