IGNITION PROJECT

[Alain Marchildon]

>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
intelligence.
>
>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 turbots 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 control of ignition events by other systems (e.g., 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 immediately:
>
>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)
>



Hi Mark

I posted this a week ago and did not get any reply=92s=20

/ Hi all=20
/
/ I would like to build a simple ign retard box similar to the ones by
Jacobs and many others, i have a=20
/ 84 RX-7 GSL-SE this is the first year they put a 13B with fuel injection.,
i will be adding a Vortech=20
/ supercharger soon and i was thinking a using a MSD with boost retard but
hey this list is up to this task.
/ The rotary engine has a similar firing as a 4Cyl engine so don=92t be=
 afraid
of it !=20
/
/ I would prefer to use a 68HC11, i have a proto board for this.
/
/ I plan on locking the mechanical and vacuum advance and us a lookup table.
/=20
/ The ign pulse would come from the magnetic pickup process it, then send it
to the amplifier and to the coil.
/
/ Ultimately there would be a knock sensor just for safety if ever i go over
board with the timing or get a bad / batch of gasoline, but the main input
for controlling the amount of retard would be vacuum/boost and=20
/ RPM.
/
/ If this is to complex maybe just have everything left alone and retard the
timing proportional to boost.
/
/ I could build the board program EPROM=92s but where i lack the most is in
the software skills kneaded for
/ this type of project any one interested give me a buzz.

=20
 So as you can see i am very interested

Why would you use a temp sensor       =20
=20
For a knock sensor you could use the Harris HIP9010  =20

Features
=7F Two Sensor Inputs
=7F Microprocessor Programmable
=7F Accurate Filter Elements
=7F Digitally Programmable Gain
=7F Digitally Programmable Time Constants
=7F Stable Analog Filter Characteristics
=7F On-Chip Clock
Operating Temperature Range -40 o C to +125 o C
Applications
=7F Engine Knock Detector Processor
=7F Analog Signal Processing where Controllable Filter Characteristics are
Required

and for MAP i would suggest a standard GM or Ford part they are easy to get
and are available in the 1,2,3 BAR range for people not requiring the 3 BAR
it would give a better resolution they use a lower BAR value, the EFI_332
list are using a 58X wheel as a crank trigger i also would prefer to use
this wheel because when the 332 MPU is finished i would use it to control
the FI and INJ all in one box.

See Ya
=20
// Marchildon at usa.net                                            //
// Alain Marchildon                                              //
// 1984 Mazda RX-7 GSL-SE Soon with Vortech supercharger "My toy //
// 1989 Audi 90 "Family car"                                     //