Shaun,
Thanks for the reply, let me see if I can answer. I must say that I
didn't type all of that
info in on the earlier post, came from the Bosch web-page. In theory,
the number of cylinders
should not make a difference on O2 in the exhaust, combustion should be
the only controlling
factor (fuel/air ratio, burn, misfire, etc). The O2 sensor is only
looking at the ratio of oxygen
in the exhaust stream, and the oxygen outside the exhaust pipe, and
remember the exhaust
stream is constently changing. Lean conditions (extra O2 in the exhaust)
generates low
voltages at the O2 sensor (0 volts), rich conditions (no O2 in the
exhaust) generates high
voltages at the O2 sensor (+1 volts). These voltages constently change
during operation.
Little known fact, Cats actually store O2 (lean burn cycles), and
release O2 (rich burn cycles)
to burn off HC's. On the Dodges (pre 1996, OBD), on the LDC (light duty
cycle) engines, only
one oxygen sensor is used and looks at all cylinders (4,6,or 8,
depending on the engine).
On the HDC (heavy duty cycle), engines, two O2 sensors were used (the
right bank, and the
left bank) and are NOT tied together before the computer, (pins 23, and
41). What they do
with the seperate inputs INSIDE THE COMPUTER, is anyones guess and Dodge
won't tell.
What I would like to see, would be the left bank O2 readings control the
left bank of injectors
(pulse width ), and the right bank controlling the right. What I would
really like to see would be
an O2 sensor at every cylinder, that way we could control fuel flow on a
cylinder by cylinder
basis and better match the air flow balance of the intake system.
Linking two seperate O2
sensors I really have no idea what this would buy you. We do want to
keep the output
of the O2 sensor as close to what the computer expects it to be as
possible. Operating
temperature (idle and steady state) are effected by this. I too have a
headache. Your not far
from me, one of these days, you'll need to stop by the shop and check
out the engines
were building.........
Frank
> -----Original Message-----
> From: Shaun.Hendricks@bergenbrunswig.com
> [SMTP:Shaun.Hendricks@bergenbrunswig.com]
> Sent: Monday, August 03, 1998 5:00 PM
> To: dakota-truck@buffnet.net
> Subject: RE: DML: Exhaust question
>
> Okay, I feel edumacated now... ^_^
>
> Frank;
>
> Thanks for the description. I kinda figured it was something like
> that,
> (or resistive in nature) so I'm fairly clear on what's happening.
> What I'm
> not so clear on is whether 8 cylinders or 4 would make a difference to
> the
> computer. In theory, the *ratio* of exhaust/O2 remains the same no
> matter how
> many cylinders are firing. The amount of O2 would increase
> (obviously) with
> more cylinders as the exhaust volume increases. So if the computer
> sees that
> it's dumped fuel amount X into the engine and sees only the voltage
> back from
> the sensor for half of the normal amount of O2: well, I guess you'd
> have a
> problem real fast. The question becomes:
>
> If you linked 2 separate O2 sensors (one on each exhaust system: in
> that
> stratigic spot[however that's calculated!) so that their combined
> (additive) voltage is returned to the computer: would the computer see
> that as
> accurately as in a single exhaust system?
>
> All of this becomes moot if the O2 sensors are on the exhaust
> manifold (or
> headers) doesn't it? I suppose if they follow the catylitic
> converters though
> it becomes real critical. Now I have a headache... >_<
>
> Shaun
> Tustin, CA
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