Narrow and Broad band O2 sensors and open vs close Options

[lmcchesney]

Sorry guys, but I've been doing some reading again. Dave, you and I have had some of this discussion before and I would respect your continued thoughts on this setup. The crux of the matter requires understanding of the circuit utilized to turn the lamba analog data into useful information. Well, here goes.
O2 sensors in a distal position provides indirect input for the estimation of the A/F ratio seen by the engine. This information is useful in defining a lean or rich mixture seen by the sensor for the most recent peroid of time. Broad band O2 sensors are capable of producing a wide range of output voltages which can be inturpeted for measuring the ratio. In fact, the output from broad band sensors can be feed into the Electronic Control Unit several times a second. This allows for real time adjustment of the A/F mixture. Thus output from the O2 sensor is recieved as input by the ECU which inturn alters injector time/volume to preprogramed mixture. This feedback/adjustment defines a closed loop system.
Narrow band O2 sensors also read A/F ratios. However, A/F mixtures ranging from 13.7:1 to 14.4:1 results in a change in voltage output from lowest to highest (0.1v to 1.0v).
If you use a analog voltmeter or equalivernt A/F gague, the response rates are such that your readings bounce requiring seat of the pants estimate as to where the mean is.
However, with the use of circuitry involving a IC unit, the voltage output can be lengthed to a series of LED's.
My question, can not a narrow band O2 sensor be utilized to monitor A/F ratios throughout the power band. Noting the results, provide information for enrichment/leaning in the adjustable ranges of D-jet. ie, idle, partial throttle and WOT.
Cannot in dash monitoring with such an A/F circuit be helpful to identify serious alterations in the engine and prevent damage from excessively lean running?
Cannot the useful information from such an A/F monitor be inproved by silmiltaneous monitoring of CHT/oil temp?
I still do not understand the advantages of a broad band O2 sensor when used in a open loop system.
I cannot also see the significant advantage of a heated O2 sensor for monitoring the A/F ratios during that first 3 minutes.
Thanks,
L. McChesney

[lmcchesney]

Thanks all,
Dave H., you are exactly right. I appreciate your experience with use on the megasquirt.
My purpose is in a open loop system, or the output of the sensor does not feed directly into the ECU.
I want to fine tune the MPS/CHT of the D-jet to prevent lean burn of the engine and to optimize the effiency.
lapuwali, if our desired range is 12.1 to 15.3 then the NBO2 sensor Bosch 11027 with circuit will cover that range.
LED Voltage Range Lambda Air/Fuel Ratio Output Torque Observations

>945mV <0.80 <12 <98% Too rich, power loss
900-945 mV ~0.85 ~12.5 100% Maximum power
855-900 mV ~0.90 ~13.2 99% Good operation
810-855 mV ~0.93 13.8 98% Good operation
540-810 mV ~0.97 14.3 98% Good operation
225-540 mV ~0.98 14.4 97% Good operation
180-225 mV ~1.0 14.7 97% Good operation
135-180 mV ~1.02 ~15 96% Good operation
90-135 mV ~1.04 ~15.3 95% Maximum economy
45-90 mV 1.05-1.25 15.4-18 74-94% Pretty lean
All out <45 mV >1.25 >18 ? Too lean, misfires

Temp variation can be stabilized with a heated NBO2 sensor, correct?
I believe WBO2 sensors have been used in several late model cars, NK etc., so they must be in the salvage yards with their bungs as well. Is there not a circuit we can make which will provide our needs with a WBO2 sensor for in dash monitoring?
Tim T, I looked at the Tech Edge.com site and it will take longer to review all of the products, and circuit. However, with purchase of the o2 sensor in US the cost for monitor, readout and sensor in a DIY kit is $235 plus shipping and building time.
If you do go with a WBO2 sensor, which has a some what linear mv:A/F ratio, how hard would it be to design/build a readout? I have a A/F meter made by Sunpro from my _LAPS ( complient with new forum standard of deciency) but cannot find the web site to understand its compoents and capabilities.
Does anyone know what model cars would have a useable WBO2 sensor that we can salvage from a yard to make a circuit? I believe that there is enough intrest in our group and knoweldge that it could make a reasonable project and PP tech article.
I also remember a PP tech article on building a A/F monitor with LED display, but for the life of me, cannot find it again.
Thanks,
L. McChesney