WB O2 Output Board Comments

[bcroe at juno.com]

Tim Burgess,

I believe your purpose here is to use the Narrow
Band (NB) signal when running closed loop, and
making the Wide Band (WB) information available
in open loop modes, so a single ecm input can
support both closed loop and WB logging at an
output channel.  I need to be convinced this the
best approach for several reasons.

The big problem will be deciding when to switch 
the MUX.  Only the ecm knows for sure exactly
when it is running closed loop, will it provide a 
signal, and what are the specifics of that signal?

Next problem is, how does the log record know 
when the switch has occured.  Will it have another
input to check the MUX control?  

My prefered method would be to leave a NB signal
connected all the time, whether it be a NB sensor
or a processed WB signal.  Feed the (suitably
scaled) WB signal into another analog channel to
allow logging, or for some just go straight into the
logging device.  Experimenters could still cook up
special versions for themselves.  To get the output
board done promptly for general use, it should 
try to provide items with proven designs or very short
development time.  But if you have a debugged 
design ready to go, it could be a go.

Does this message need to be forwarded to get to
Tim Burgess?

Bruce Roe, EE trying to understand engine tuning


On Sat, 18 Aug 2001 20:11:05 -0400 rr <RRauscher at nni.com> writes:
> [Fwd: from the diy-efi list]

> Timothy J Burgess wrote:

> > Greetings and congratulations

> > It may be useful to provide a second output that is 
> > scaled such that 0.1 volts = 10.8:1 and 0.9 volts 
> > = 13.07:1 (essentially by subtracting about 1.3 volts 
> > from the existing output).  This output could be applied 
> > to an analog mux that selects the stock O2 sensor 
> > output under part throttle and selects the WB O2 
> > sensor output at WOT.  The output of the mux 
> > would connect the the ECM O2 sensor input.  This 
> > would allow easy WOT A:F ratio data capture using 
> > the A to D in the ECM in conjunction with an AutoXray
> >  or Diacom, etc., and would also allow the ECM to 
> > continue to operate normally at part throttle.
> 
> Sounds like a mux should be added to the general 
> output board. I'll keep this in mind. We are working on 
> a couple of different options at this time. The re-scaling 
> of the WB output to an ECM O2 input in one of them. I'm 
> not positive if someone has started working on this 
> one. I'll ask and if not would you care to? Probably put 
> them all on the same PCB. Good input.
   


> > I'm an EE and moderate the electronics board on 
> > thirdgen.org, so I look forward to seeing you there, as well!
> >
> > Tim Burgess
> 
> Welcome aboard,
> 
> BobR.
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