Wide Ratio O2

[Raymond C Drouillard]

On Sat, 28 Mar 1998 05:39:56 -0600 Steven Gorkowski <kb4mxo at mwt.net>
writes:
>Gar
>
>I think you have a good handle on the wide ratio project and will be
>waiting for your results . I have a person to test the O2 meter curves 
>.
>My goal is to make a very cheap (under $100) meter, very low parts count
>and a serial data stream and linear 0 to 5v out option.
>
>Steve
>

I have been following this thread.  I am thinking of going with a
wide-ratio O2 sensor in my Pro-Jection system.

Pro-Jection allows you to set the desired output voltage for the O2
sensor.  There is a table that can be modified.  That means that you can
set the mixture slightly rich at high manifold pressures (for power), and
set it lean at lower manifold pressures (for economy).

With the current sensor, that whole idea is a farse.  The ECU controls
the injecters, but the result is a constant bouncing between 0V to around
0.85 volts.

It does this (I am theorizing) for two reasons:
The sensor is a big farther downstream than I would like (in the "Y"
pipe), and it takes so little change in A/F ratio to move the sensor from
one extreme to the other.

My idea is to calibrate the wite-ratio sensor so that it can sense a bit
beyond the extremes that I want to run.  This should allow the feedback
circuitry (or program) in the ECU lock on better.

In other words (for the EE crowd), I will be reducing the gain in the
feedback circuit, which will move the poles to the right.  If I get it to
the right of the J-Omega axis, the system will stop oscillating.

Ray Drouillard

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