Zirconia O2 sensor alternate modes of operation

[TBK]

On your original question, I would assume that any significant current
forced through the O2 would damage it.  It's impedance must be lower than
the source impendance of the .45V source when it heats, so It's a battery. I
guess you could read the current through a known load. What, I don't know.

Bottom line, I wouldn't.

The only reliable measurement is .456V is stoich.

TK
-----Original Message-----
From: Zack <zubenubi at inetport.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, February 22, 1998 10:23 AM
Subject: Re: Zirconia O2 sensor alternate modes of operation


>TK,
>
>Ahh, so the GM ECU >doesn't< read the current.  That's what I thought.
> So anyway, back to my original question, if I bias the sensor with a low
>voltage and read the current flowing through it, do I have the potential to
>damage it in any way?  And if not... over what range of A/F ratios can I
>get a reliable measurement?
>
>Zack
>
>----------
>> From: TBK <terryk at foothill.net>
>> To: diy_efi at efi332.eng.ohio-state.edu
>> Subject: Re: Zirconia O2 sensor alternate modes of operation
>> Date: Sunday, February 22, 1998 1:13 AM
>>
>> I think it is .456V supplied through 1Mohm. When the sensor heats, it's
>> resistance drops and can now overcome the bias voltage. The .456V is just
>> there to fool the ECM until the sensor is warm.
>>
>> Right or wrong Peter?
>>
>> TK
>> -----Original Message-----
>> From: Zack <zubenubi at inetport.com>
>> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>> Cc: nacelp at bright.net <nacelp at bright.net>
>> Date: Saturday, February 21, 1998 10:57 PM
>> Subject: Re: Zirconia O2 sensor alternate modes of operation
>>
>>
>> >Bruce,
>> >
>> >So you're saying the GM units bias the sensor and read the resulting
>> >current?
>> >Interesting, I didn't know there were any production cars that used that
>> >method.
>> >
>> >Zack
>> >
>> >----------
>> >> From: bruce plecan <nacelp at bright.net>
>> >> To: diy_efi at efi332.eng.ohio-state.edu
>> >> Subject: Re: Zirconia O2 sensor alternate modes of operation
>> >> Date: Sunday, February 22, 1998 1:11 AM
>> >>
>> >> In the GM applications I've worked on, all had a .44v applied to
>> >> the O2 sensor, didn't matter if they were heated or not.
>> >> Bruce
>> >
>>
>