More UEGO stuff

[Raymond C Drouillard]

Oops... 

Nope, not making light of Steve's work.  Having had my hands into a few
designs, I know that designing a simple circuit can be more difficult
than designing a complicated one.  The basic circuit for a UEGO sensor is
simple, but actually assigning values to the components can take a lot
more time.  Also, it takes some real thought to keep the parts count from
bloating as you make adjustments here and add features there.

I am especially curious about that calibration resister.  I could
probablly figure out how to hook it up so that the circuit will be
self-calibrating, but it would requre either some information that I
don't have, or a test with some good test equipment and several sensors
from different batches.

For my application, it doesn't matter much.  All I want is an output that
I can divide down to 0-1 V and feed into my Holley Pro-Jection ECM.  I'll
just start leaning it out at cruise until it's too lean, then enrich it
until I get it right.

I'll do something similar at WOT.  It's really cool that Holley allows
you to adjust the "set point" table.  That feature is useless with a HEGO
sensor, but will be very useful once I get my hands on a UEGO sensor.  I
wonder why Holley put that feature into their ECM.

Ray



On Sun, 31 Jan 1999 00:07:07 -0500 "Bruce Plecan" <nacelp at bright.net>
writes:
>
>-----Original Message-----
>From: Raymond C Drouillard <cosmic.ray at juno.com>
>To: diy_efi at efi332.eng.ohio-state.edu 
><diy_efi at efi332.eng.ohio-state.edu>
>Date: Saturday, January 30, 1999 11:39 PM
>Subject: Re: More UEGO stuff
>
>Gee, sounds so easy.  Hmm, care to whip up a ION?.
>I certainly hope you weren't making light of Steve's work.
>Bruce
>
>
>>I would buy one.  Of course, if I happen to "stumble" across a design
>>before the kit is available, I would simply build it myself.  The
>>circuitry on a UEGO isn't all that complicated.  In its most basic
form,
>>it is a single op-amp and a few discretes.  Add a few more components
for
>>a double-ended power supply, something to shut off the ion pump when
it's
>>not warm, something to regulate the heater, and you have it.
>>
>>Ray Drouillard
>>
>>
>>On Sat, 30 Jan 1999 14:25:13 -0600 Steve Gorkowski <kb4mxo at mwt.net>
>>writes:
>>>If one would come as a kit for under $200.00 with sensor. How many 
>>>would
>>>buy the kit ? No sense to design if one if no one was interested in 
>a
>>>wide O2 meter.
>>>
>>>Steve
>>>
>>>Mike Pitts wrote:
>>>
>>>> Any interest?  Is this a waste of bandwidth?
>>>>
>>>> "This invention provides an self-calibrating buffer amplifier
>>>> for a Universal Exhaust Gas Oxygen sensor interface circuit
>>>> which couples and processes a voltage signal proportional
>>>> to pumping cell current to a level and reference voltage suitable
>>>> for input to an A-to-D convertor. The goal of this invention is to
>>>> increase the accuracy of air-to-fuel ratio control by continually
>>>> correcting for the effects of offset quantities in the amplifier
>>>> stage necessary to the interface circuitry. This goal is 
>>>accomplished
>>>> by an approach which effectively generates and subtracts these
>>>> offset quantities from the processed signal. "
>>>>
>>>> http://patent.womplex.ibm.com/details?pn=US05211154__
>>>>
>>>> -Mike
>>>
>>>
>>>
>>>
>>
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>
>

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