UEGO and alcohol

Walter Sherwin wsherwin at home.com
Wed Sep 27 02:28:01 GMT 2000


Yup.  Maybe if people were convinced/coerced into thinking along the lines
of of "Lambda" values (instead of gasoline A/F values), then the message
might possibly sink home.  Stoich is stoich, no matter the fuel, in the
presence of an NTK/NGK sensor.  Lambda = 0.8 is then fairly meaningful to
the task at hand.......


Walt.



> At 8:29 PM 9/24/00, Jeff Bromberger wrote:
> >I'm looking to tune WOT w/nitrous and alcohol, so i need something much
> >richer than stoich. My question is basically whether or not the sensor
will
> >reflect the actual ratios of liquid fuel to air or not. Accel claims that
> >you need "a true wideband sensor to tune alcohol because it's out of the
> >range of the 5-wire sensors like SpeedPro uses"... this is more or less
what
> >i was trying to verify. If the alcohol appeared as 6:1 (vs. 12:1 for gas)
> >then this would make sense...
>
> Maybe if I say it again, you will hear what I am trying to tell you. An
NTK
> UEGO sensor will see stoich as stoich, no matter what fuel you are
running,
> so long as the fuel doesn't foul the sensor. 14.7:1 is stoich for a
typical
> GASOLINE. 6: 1 is stoich for methanol. 8:1 is about where stoich is for
> ethanol. A UEGO controller, such as EGOR, or the NTK "blue box" will give
> exactly the same voltage output at the stoich mixture for any given fuel,
> REGARDLESS of whether stoich happens at 14.7 to 1, 6 to 1 or 8 to 1!! The
> voltage will vary one way as the mixture goes rich of stoich, and the
other
> way as the mixture goes lean of stoich.
>
> With methanol fuel, I would bet that a UEGO would work OK down to as rich
> as about 4.2 to 1.
>
> BUT--if you have a UEGO METER with a digital output---you will get screwy
> numbers out of it unless it (the numbers that correspond to a particular
> output voltage) is recalibrated for whatever fuel is being used.
>
> For instance--if you are using a digital UEGO meter which is calibrated
for
> gasoline on an alky motor, I would bet on it reading 12.0 to 1 when the
> mixture was really about 4.9 to 1 !
>
> Greg
> >
> >
> >> It's a matter of calibration, Jeff. The sensor/driver/meter will read
> >> stoich wherever the alchohol mixture is stoich, and rich and lean to
> >either
> >> side of it. The only question is--what number will the meter give you
when
> >> you are where???
> >>
> >> The actual VOLTAGE output from the sensor/driver will be the same at
> >stoich
> >> for alky as it would be for stoich for gasoline, etc.
> >>


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