Affordable Wideband ECUs - How to?

[Garfield Willis]

On Fri, 31 Mar 2000 13:43:25 -0700, Chad <chad at dynojet.com> wrote:

>I have a unit up and running right now that does exactly that, allow the 
>user to change the stoich point that the O2 sensor reports.  It works quite 
>well, and you can watch the A/F change as buttons to rich/lean are 
>pushed.  The flaw in getting the ECU to continually run in closed loop is 
>that this is only manipulating a control input. In effect, you are *asking* 
>the ecu to change the pulse width to the injectors rather than forcing it 
>to run in a certain way.  The changes only occur at idle and cruise, when 
>the ecu is paying attention to the O2 signal input.  With the experimenting 
>I've done, I agree that you need to have more authority (source code) in 
>order to force the ecu to do what you want it to.

Hey Chad.

Yeah, I agree the hard part isn't the simulation of a switch-type O2
sensor, tho I wouldn't diminish the usefulness of that; good experiment.
As you say, just controlling the stoich switch-point is "pushing on a
string". We need much more forceful measures. But there ARE (I
understand from them-what-nose :) some params on some ECUs regarding the
TPS and load limits (not to mention temp inputs) where you can say "thou
shalt go to open-loop". The hope was that by constraining these, you
could effectively TELL (not ask) the ECU to be in closed-loop, I guess
by process of elimination. There would still be lots of situations like
cold-crankNstart, warm-up, etc. where you'd want to be running outta
tables, but the real critical question is whether you can TELL the ECU
during major TPS and load regimes to "stay in closed-loop". I'm probly
dreamin to think it could ever be that straightforward; but it's just so
damned 'desirable' to imagine being able to fashion the OEM ECUs into
closed-loop controllers that I'm probly in denial right now about the
doability, and still clinging to a mere thread of hope that it could
still in some way be possible.

Being able to say "anti-gravity" doesn't make it any easier; but ya
gotta have dreams. :)

Gar


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