Fw: Wide band O2 ????

[adrian.culda at sympatico.ca (Adrian)]

Well Wide bands work on a different system than the old narrow band
sensors.
They are far more accurate due to the stable operating temperature. Not
only that but the latency of the narrow band O2 sensor is about 0.5 (~2
samples/sec.)second compared to the wide band which is 0.03 (~25-30
samples/sec.)!!!

How the O2 Sensor Works 

The oxygen sensor detects oxygen in the exhaust in a way similar to a
battery cell. Platinum layers on the inside and outside of the probe act
as electrodes. Zirconium dioxide between the layers of platinum acts as
an electrolyte. The inside layer of platinum is exposed to the air in
the engine bay, the outer layer is exposed to the exhaust. When the O2
sensor is hot it generates positive voltage between the two layers of
platinum. Negatively charged oxygen ions in the exhaust are attracted to
the platinum and reduce the voltage that the Engine Control Unit and
air/fuel gauge reads. 

That's why a rich mixture = higher voltage from the sensor (more gas =
fewer negative O2 ions to drop the voltage). Just remember "L=L", Lean =
Low voltage. You can attach a Volt Ohm meter (black to ground, red to
the O2 sensor) to monitor your engine's air/fuel ratio. I suggest you
have a co-pilot read the voltage while you accelerate at full throttle. 

The 3 wire sensors are used to give power and ground to pre-heat the
sensor so it starts working quicker and it has no effect after the
sensor gets warmed up. 



Adrian C.
Project Scirocco R2.oT - "The Turbocharged 16Valves of Fire Breathing
Fury"
( 2.0L 16V T66 )
 

-----Original Message-----
From: scirocco-l-bounces@scirocco.org
[mailto:scirocco-l-bounces@scirocco.org] On Behalf Of
mr.utility@highstream.net
Sent: October 24, 2003 11:29 AM
To: Dan Bubb
Cc: scirocco-l@scirocco.org; Ron Pieper
Subject: Re: Fw: Wide band O2 ????

Quoting Dan Bubb <jdbubb@ix.netcom.com>:


> 1. control the current to it's heater to maintain the sensor
temperature in a
> narrow band despite exhaust heat input (or lack thereof) 

> Dan
> 
> 


Correct me if I am wrong, but the only time the heater is used is at
initial 
start-up, when the sensor is cold?  I was under the impression that that
was 
the only time the heater is used, to further diminish emissions when the
O2 is 
cold and not yet able to function completely....

David


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