O2 voltz

[Steve Gorkowski]

So what you are saying is that what Bruce is doing wasting his time ? He can't
read  AFR off  the 14.7 value? If you could give me the range AFR numbers when
sensor is corrected for temp or are you saying this will not help expand the
range? Can you define very narrow range (numbers please)?

Have a great day
Steve



G. Scott Ponton wrote:

> Ok guys I have sat back and waited for awhile for you all to get this
> straight. The sensor "compares the amount of oxygen in the exhaust stream
> with the amount in the outside air.  The reason it doesn't seem to work this
> way is two or three fold.
>
> 1. The sensor needs to be at a "reasonably" stable temp before its output is
> "reasonably" stable.
>
> 2.The sensor only works in a very narrow A/F ratio. As the amount of oxygen
> climbs above a certain point it can't drop the voltage any lower and the
> oppisite is just as true. The output voltage is also limited by the design
> of the sensor. After a point removing more oxygen can't effect a voltage
> change.
>
> Much has been said and made of the "wide band" sensors too. After reading
> much on the "wide band" sensor it works exactly the same way as a "normal"
> sensor. The difference is through outside influences, either a standard
> sensor or electronics atached to the output, are used to create a "current
> pump" when the sensor cross stoich the "outside" control device switches the
> current in the sensor so that it breaks oxygen atoms away from the oxidized
> gases in the exhaust. By know at what rate this happens chemically we can
> use the output of the sensor to "roughly" ( better than what we started
> with) determine the amount of oxidized fuel (and other such nasties as NOx)
> in the exhaust stream.
>
> Notice the word normal used to desribe combustion as we currently use it on
> a daily basis. This doesn't include off the wall or experimental engines
> which use some sort of modifided combustion cycle. Why not you ask? This is
> going to get very long if I have to get into everything that can effect
> this. Simply put:
>
> Within the range of "normal" combustion, a little either side of stoich, the
> leaner the mixture the greater the amount of free oxygen in the exhaust
> stream as there isn't enough fuel to combine with all the oxygen in the
> cylinder. As the mixture is enrichened the amount of free oxygen drops for
> exactly the opposite reason.
>
> If you go to the point of misfire all bets are off. Although a lean cylinder
> will tend to dump more free oxygen into the exhaust than a rich one as until
> the mixture is extremely rich some part of the air charge ingested will be
> used as the fuel attemps to oxidize ( burn) whereas in a extremely lean
> cylinder next to nothing oxidizes as our current ignition system cannot
> produce the energy needed to properly promote combustion of these mixtures.
>
>    Testing a sensor with argon and other similar gases doesn't work very
> well unless they are in an enclosure with only the tip of the sensor exposed
> to the "inert" gas. I won't try to get into ther chemistry involved at this
> moment as I will have to research the chemistry of inert gases before I can
> explain it in those terms. At this point my chemistry is rusty to say the
> least. At least that part of it which doesn't deal with the above as I use
> this nearly every day.
>
> OK let the flames begin!! LOL :-)
>
> Scott