DIY-WB Output Voltage Scaling

[Len Sabatine]

    BobR , as usual, you've got your ducks in line.
    Maybe a work around to avoid crispy piston decks , would be the development
    of a WB "look alike" input to the PCM's O2 channel [s] , with necessary 
program
    code that would default to normal NB monitoring and control. MAYBE this 
could
    be useful to avoid catastrophic engine damage in the event of the WB 
ckt/ sensor
    failure , assuming the WB is the primary monitor in use.
    This isn't a trivial endeavor.
    Len

>I've had a lot of people ask about having the WB control the AFR under
>WOT. Just scares the dickens outa' me. Anything goes wrong with the
>sensor or electronics and the pistons find a new home in the oil pan.
>
>That and of course then need to run the WB all of the time. . .
>
>BobR.
>
>Len Sabatine wrote:
>
> >      Taking note of commanded AFR, It's just that , Commanded in the Narrow
> >      NB O2 stoich "window". Changing this narrow commanded range would no
> >      doubt be a good deal of work to get it right.
> >      In WOT mode , having the latitude to actually compensate and 
> control AFR
> >      versus the fixed 128 # may offer rewards. In a manner of speaking ,
> > adding
> >      another Intergrator for WOT operation , using the WB input.
> >      Getting the PCM to alter it's thinking in this area, could be
> > difficult , it's ignoring
> >      O2 corrections and using WOT table lookup.
> >      Now . if your PCM has a setting for TPS-WOT mode , it's easier to
> > accomplish
> >      changes necessary , but with very cautious Monitoring of EGT.
> >      FYI , the LS6 C5 PCM does WOT AFR control, of which , I'm sure the 
> code
> >      has been altered to accomplish this.
> >      Most ECU's are doing the same operations, at different addresses and
> > timing
> >      routines per ECU's. This is where "same thing , but only different "
> > enters .
> >
> >      With the tools and talent of the Diy-Efi membership in collective
> > effort, amazing
> >      things are possible. IMHO.
> >     Len
> >
> > >Sounds like a great idea BUT unfortunately we are all using different 
> ecu's
> > >and code so it would be hard to do.
> > >I like the idea and if we had enough programmers amongst us that could 
> teach
> > >us how to add code to our respective ecu's
> > >
> > >Take this a step further and get the table lookup to compare WB A/F 
> ratio to
> > >a commanded A/F ratio table and then adjust a WB  BLM to achieve 
> closed loop
> > >A/F ratios at points other than Stoichiometric ?
> > >
> > >
> > >Daniel
> > >
> > >
> > >
> > > > At 09:36 AM 8/25/01 +1000, you wrote:
> > > > >It should be pointed out that the current incantation of the
> > > > >DIY-WB unit has a non-linear voltage:AFR transfer function.
> > > >
> > > > Here's an Idea!!  hook it up to an extra PCM input, and have the pcm
> > > > table lookup the AFR(like it does volts to whatever for MAP, temps, 
> etc),
> > > > put it in the aldl datastream and have your palm
> > > > pilot display it for ya.
> > > >
> > > > Doa!! if only I could get successfully started on the serial 
> communication
> > >part
> > > > of a palm program.
> > > >
> > > > ----------------------------------------------------
>
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