Wide band O2 sensor for control of combustion.

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by sorka, Jan 14, 2008.

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  1. sorka

    sorka
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    I'm surprised this isn't standard on all pellet stoves these days. Having to fiddle around with the damper to get/guess at the right air fuel mixture just can't be efficient.

    I have a Bosch wide band O2 sensor and a controller which heats it up and does the conversion. It also has a mappable 0 to 5.0 v analog output. I'd like to weld an exhaust bung on the appliance adapter and use the output of the O2 controller into a general purpose pid controller which would in turn control a stepper motor attached to the damper rod.

    Are there any stoves out there that have closed loop air fuel combustion like cars have had since the previous millenium?
     

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  2. hearthtools

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    autraflumm used this kind of sensor
     
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  3. pete324rocket

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    I agree. I have been experimenting with a magnetic flue thermometer stuck to the upper left front door of the pellet stove to see what difference is made in temp. by having a high draft low flame fire vs. a large flame-not lazy-but bright. I am surprised that the low aggressive flame seems to produce as much if not a little more heat than the bright flame. Funny because the bright flame seems to radiant more heat through the glass-or so it would seem. Still testing but keeping a record thru all the heat levels.Does anyone know if some pellet stoves come with a thermometer gauge- sure would be a handy thing if it provided a better reference to greater heating value from the pellets.
     
  4. tkirk22

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    I have one of those units too. I'm not sure how well the sensor would work in a flue though. If you try it, let us know.
     
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  5. bdcbean

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    Any luck with this?

    I don't think Austoflamme use an 02 sensor at all, I believe they just have a exhaust temp sensor which gives them a larger range of settings in their program rather than a set thermal switch.

    A wideband 02 would not work too well on a pellet fire because the changes are not instant unlike a car where if you change the fuel amount it will be.

    I have done a lot of thinking on this also, and it just seems that the combination of AC draw fan and auger, that kind of control is not going to happen.
     
  6. R&D Guy

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    What kind of pellet stove do you have, and are you just burning pellets? Sounds like its just not set up correctly, and, or you need to stop playing with the damper. What gives you the idea it's not burning correctly, or are you just trying to get the most perfect combustion possible?
     
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  7. Kenny1

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    Would an O2 sensor work in a solid fuel exhaust stream? Would it work after being covered in soot?

    Cheers

    Kenny
     
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  8. bdcbean

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    I would imagine the soot would not be good for it.. as well as the corrosive leftovers. They don't last long with lead fuel in cars even.

    As RND said though, why would you need this kind of fine adjustment? The program should control the fire as well as possible once the fire is setup correctly. What exactly are you going to adjust with the data the 02 sensor provides? Fan speed (ok you can't control an AC fan that easily on a fine scale) or the Auger speed (which we know is not constant anyway).
     
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