Oxygen sensors switching
Oxygen sensors switching
As I have heard some differing opinions, I am interested in forum members opinions on what controls/generates the oxygen sensor stoichiometric switching voltage in narrow band oxygen sensors.
- vlad01
- Posts: 7801
- Joined: Mon Oct 08, 2012 6:41 pm
- cars: VP I S
VP I executive
VP II executive
VP II executive #2
VR II executive - Location: Kyneton, Vic
Re: Oxygen sensors switching
As from what I recall when I researched them recently, it's the flow of oxygen ions mediated by the porous platinum catalyst electrodes through the porous zirconium ceramic. The flow is due to the difference in oxygen levels from one side to the other, because they are ions a voltage is generated.
Kinda works in a similar way to a fuel cell.
You will need a solid foundation in physics and chemistry to full understand the mechanism.
Kinda works in a similar way to a fuel cell.
You will need a solid foundation in physics and chemistry to full understand the mechanism.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
-
- Posts: 1833
- Joined: Sat Aug 06, 2011 7:58 am
- cars: V8 VR Commodore BT1
LB Lancer 2L turbo & Delco
Starion TBI with Delco
Mitsubishi Lancer EVO4 track car
NA MX5
3 vintage motor bikes - Location: Padstow NSW
Re: Oxygen sensors switching
Vlads on the money with how they work. I have seen cars that go into car washes and 4WD have issues after water and mud block off the atmospheric side of the sensor. More importantly is how fast the sensor switches.
Re: Oxygen sensors switching
vald01 & Charlescrown ..Thanks for the response, this also is my understanding of oxygen sensors function by measuring the oxygen level in the exhaust gas stream and comparing the oxygen level in the atmosphere through a hole in the oxygen sensor shell or through the wiring entering the oxygen sensor (this is why measuring AFR at the tail pipe can give a false reading contaminating the sample atmospheric oxygen with exhaust gas).
However there has been a comment that the actual switching of the sensor to maintain stoichiometric is generated by the oxygen sensor, not as generally believed it is the PCM controlling this function this is the area I was looking for comments on.
However there has been a comment that the actual switching of the sensor to maintain stoichiometric is generated by the oxygen sensor, not as generally believed it is the PCM controlling this function this is the area I was looking for comments on.
-
- Posts: 1833
- Joined: Sat Aug 06, 2011 7:58 am
- cars: V8 VR Commodore BT1
LB Lancer 2L turbo & Delco
Starion TBI with Delco
Mitsubishi Lancer EVO4 track car
NA MX5
3 vintage motor bikes - Location: Padstow NSW
Re: Oxygen sensors switching
I believe it's the PCM changine the mixture and the O2 sensor responding which occurs rapidly and is seen when logging. The swing is quiet wide between 200 to 800mv which is pretty much max in either direction.
- antus
- Site Admin
- Posts: 8253
- Joined: Sat Feb 28, 2009 8:34 pm
- cars: TX Gemini 2L Twincam
TX Gemini SR20 18psi
Datsun 1200 Ute
Subaru Blitzen '06 EZ30 4th gen, 3.0R Spec B - Contact:
Re: Oxygen sensors switching
Absolutely, the sensor is an input to the pcm, the sensor has no control over the flow of air or fuel to change the ratio. it has to be the computer as thats controlling the fuel via injection. It is true that in closed loop the computer is reading the o2 and fueling based off that, so indirectly it is from the o2 but its still the pcm thats doing it, not the sensor directly, or in hardware.
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
Re: Oxygen sensors switching
Thanks for the opinions, my understanding is in line with Antus comments, as there are some informed people on this site i just thought I would ask the question. Thanks to all that responded.
-
- Posts: 440
- Joined: Sun Mar 22, 2009 11:52 am
- cars: VT V6 supercharged in a corolla
- Location: Sydney
- Contact:
Re: Oxygen sensors switching
You can see how quick the O2 voltage switches in this youtube clip at approx 4.20 minuetes in.
https://www.youtube.com/watch?v=c9hX2hTBfIk
https://www.youtube.com/watch?v=c9hX2hTBfIk