Modularity, ... and pre-ignition

[John S Gwynne]

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Date: Tue, 17 May 94 11:36:53 CDT
From: Steve=Ravet%Prj=Eng%PCPD=Hou at bangate.compaq.com
Subject: re: Modularity, ...   and pre-ignition
To: twisto.eng.hou.compaq.com!wotan!coulomb.eng.ohio-state.edu!Diy_Efi-Owner
Cc: 

met at pine.cse.nau.edu (MTN-KAT) Wrote:
| 
| 

[paragraph about modularity deleted, EEs do their part, CS people
do their part, etc.]

Makes sense.  Discussion has fallen off somewhat, I guess because
the schools are between semesters?  Anyone out there not in school?


| I'll tackle the crank trigger and my idea for a digital logic 
| board that only
| requires 4 bits to operate the 8 or 16 injectors that I am 
| considering using.
| 8 injectors for gasoline and 16 for Alky, which I'd really like 
| to use. 
| The digital board will be completely portable and I also have an 
| idea to have
| it parse the signals so that only 2 bits will be required to run 
| 16 injectors.
| If you are running less than 8 cylinders it is very easy to set 
| it up for as
| few or as many cylinders as you need.

Ok, now we need some way of posting schematics, etc.  Is there a site
we can use, and what format should we use?  I would guess that postscript
is the best general purpose format for graphics.  Previewers and
converters are available for most platforms.  In addition, postscript
can directly drive a high-resolution printer to make etching masks, etc.

Back to real stuff:  One person replied to my post about pre-ignition
detection, saying that it showed up from 5-8khz.  What sort of detector would 
work to pick up this signal?  piezo-electric tape is easy, just stick it on, 
but it might have problems with the heat, and it may not have the correct 
frequency response.  how about commercial detectors?  are there sources for 
them, how much do they cost, and can they be easily interfaced?  once a 
detctor is found, what is the control algorithm for the ignition?  the 
simplest seems to be to continually advance the ignition until pre-ignition is 
detected, then retard it a little.  would this give the most power?  or is 
more feedback required, like maybe an exhaust monitor?  inquiring minds want 
to know....

Those of us who are still here, lets keep the list going.....

--steve