O2 sensor idea

[Greg Hermann]

>On Mon, 19 Apr 1999, Greg Hermann wrote:
>
>> >On Mon, 19 Apr 1999, Ken Kelly wrote:
>> >
>> >> Roger,
>> >>
>> >> The GM PCM only looks at crossings of 14.7 AFM, that is why
>> >> they are only calibrated at that point. As soon as you go to
>> >> Wide open throttle the PCM ignores the O2 sensor. If the O2
>> >> sensor was linear from 14.7 to 12.0 AFR, You could rewrite
>> >> the software, so it would stay in closed loop, but it would
>> >> be a major rewrite.
>> >>
>> >> 		Ken
>> >
>> >I know it works that way.  I just want an accurate O2 sensor so when I
>> >am burning new chips I actaully know the O2 sensor is reliable.  The
>> >diacom output should have accurate O2 readings, and then tuning would
>> >be easier.  I have to be careful right now becuase I really don't know
>> >what voltage is exactly 12.5:1, I am just guessing.
>>
>> Guessing is the right word for it, Roger. and with anything less than a
>> well calibrated wide band O2 unit, you would be continuing to guess. But I
>> think you knew that!
>>
>
>That is why I want to get a well calibrated wide band unit and setup a
>pic or something similar to give the kind of results the stock
>computer wants, and give mv readings that actually mean something.

As I said earlier, Roger, it MAY (not sure yet) be possible to bias a wide
band O2 sensor with a constant ion pumping current so that it crosses at
any A/F ratio you want, in the same way that a standard EGO or HEGO sensor
does--Changing the bias say for cruise or WOT, and leaving an oem ecm in
closed loop would allow a programmable selection of A/F ratios  for
different operating conditions. (The bias adjustment is what would fool the
ecu, the sensor would act like normal EGO sensor at 14.7:1.) The bias and
its changes would need to be dealt with outside of the oem ecu.

Regards, Greg
>
>			Roger