Ducati Monster Forum

Moto Board => Tech => Topic started by: CowboyBeebop on December 07, 2008, 12:06:37 PM

Title: What Does the O2 Sensor Do?
Post by: CowboyBeebop on December 07, 2008, 12:06:37 PM
What is the purpose of the 02 sensor?  I understand that it has something to do with emissions compliance, but how does it work?  Is it part of the EFI system?  And if its removed, does it make inspection impossible for those States that check emissions?
Title: Re: What Does the O2 Sensor Do?
Post by: Buckethead on December 07, 2008, 12:21:19 PM
It causes my bike to lurch below 4000 RPM.  >:(  [bang]

Actually, from what I understand, it is designed to send a signal to the ECU telling it to lean out the mixture if it detects unburned fuel in the exhaust gasses.
Title: Re: What Does the O2 Sensor Do?
Post by: He Man on December 07, 2008, 12:49:42 PM
it makes your life miserable and costly.  >:(
Title: Re: What Does the O2 Sensor Do?
Post by: Buckethead on December 07, 2008, 12:50:45 PM
But at least it keeps the pressure-plate zombies at bay.  [thumbsup]
Title: Re: What Does the O2 Sensor Do?
Post by: CowboyBeebop on December 07, 2008, 02:29:44 PM
So will its absence adversely affect emissions tests? 
Title: Re: What Does the O2 Sensor Do?
Post by: Buckethead on December 07, 2008, 02:36:40 PM
It could.

Worst case, I say go get the emissions test done with the O2 sensor in, then when you're home just unplug it and plug the hole in your header.

Also, having just noticed your screen name:

http://cosbybebop.ytmnd.com/ (http://cosbybebop.ytmnd.com/)
Title: Re: What Does the O2 Sensor Do?
Post by: He Man on December 07, 2008, 03:17:11 PM
ive wasted days on YTMND..captain jean-picard of the uss enterprise...... that ones pretty funny.

Theres noticebly more power on most of our bikes with the O2 in. But the bike idles better without it. you can try removing it, just make sure you take it out, otherwise you can risk damaging the sensor.


Title: Re: What Does the O2 Sensor Do?
Post by: CowboyBeebop on December 07, 2008, 03:49:28 PM
Quote from: Obsessed? on December 07, 2008, 02:36:40 PM
It could.

Worst case, I say go get the emissions test done with the O2 sensor in, then when you're home just unplug it and plug the hole in your header.

Also, having just noticed your screen name:

http://cosbybebop.ytmnd.com/ (http://cosbybebop.ytmnd.com/)

OMG that was funny!  "When I was a boy we'd play stickballllllllll"
Title: Re: What Does the O2 Sensor Do?
Post by: Howie on December 07, 2008, 04:54:36 PM
Most of you folk have been driving cars with 02 sensors for the last two to three decades.  This is a closed loop system that constantly tunes adjusts fuel ratio as you drive.  The following is a brief and simplified explanation: 

Engineers knew, for many years, the best compromise between fuel economy, emissions and performance is 14.7:1.  This also happens to be the fuel ratio where catalytic converters work most efficiently.  14.7:1 is known as stoichiometric ratio, or Lambda.  The question was how to maintain this ratio.  The secret to this is the 02 sensor.  For simplicity sake I will stick to the units used on Ducatis, which are the same as the units used in most vehicles, the Zirconia sensor.  This sensor acts like a small battery, the difference between the ambient oxygen and the oxygen content in the exhaust causes a small voltage to be generated.  A lack of oxygen in the exhaust means rich and visa verse.  This signal is picked up by the ECU, and if parameters are met, the engine is in closed loop and mixture is constantly readjusted to maintain stoichiometric ratio.  Typically, cold start, warm up and wide open throttle are open loop.

Again, this is the short, generic, simple version.
Title: Re: What Does the O2 Sensor Do?
Post by: brad black on December 08, 2008, 02:10:08 AM
long version - http://www.bikeboy.org/open_closed_loop_efi.html
Title: Re: What Does the O2 Sensor Do?
Post by: J.P. on December 08, 2008, 07:14:42 AM
Got a Cowboy Beebop t- shirt, now I gotta find a Cosby one!

Where the hell do they test scooter emissions? You gotta be kidding me.
Title: Re: What Does the O2 Sensor Do?
Post by: CowboyBeebop on December 08, 2008, 11:02:47 AM
Quote from: J.P. on December 08, 2008, 07:14:42 AM
Got a Cowboy Beebop t- shirt, now I gotta find a Cosby one!

Where the hell do they test scooter emissions? You gotta be kidding me.

I don't know, but I have a feeling that it will become common in the near future and I want to make sure I'm not doing anything to my bike that could make it fail.