PC's and EFI

[Raymond C Drouillard]

On Thu, 19 Mar 1998 02:50:55 -0600 "Matthew B. Watts"
<mwatts at facility.cs.utah.edu> writes:

<sniiiiiip>

>>The real trick is to not require the microprocessor to actually fire
>>something at a specific time.  It should calculate when and how much,
>>then load that data to something else.
>
>
>Exactly.
>
>>A sound card could easily create a waveform that'll fire an injecter.
>>Just route it to the correct injecter (perhaps based on input from an
>>RS232 port), and amplify it.  If you use a sound card with a 
>programmable
>>wave table, you can set up a variety of duty cycles and durations.
>>That'll offload a lot of processing from the microprocesser.
>
>
>True.  That's one sound card and associated I/O for each injector,
>and in many respects it's overkill, since the wave table would need
>to be constantly updated in order to get good engine response.  And
>there we are again after one, two, maybe three revolutions have gone
>by waiting for the processor to compute, rebuild, and output the new
>wave table.  It's really difficult and I don't mean to sound negative.

Actually, one sound card for two controllers (stereo).

Anyhow, what I had in mind is to send it all out one sound card, and use
eight transisters to route the signal to the appropriate injecter.

Also, the beauty of using programmable wave tables is that the computer
could define 256 or 1025 or however many tables are needed before engine
startup, and just point to the appropriate tables - just like a midi
sequencer.

Yah, it's overkill, but it's cheap.  I'll pay $25.00 for overkill before
I'll pay $100.00 for something that is adequate, but would require more
time to design.


>
>We'd all like to build a simple, 50 dollar engine management unit that
>would work even on an Indy car, but gettting from here to there is
>going to take some serious work and a bunch of good ideas.
>Keep them coming...
>
>Matt


Ray Drouillard

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