1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Exhaust gas analyzer for tuning mixture

Discussion in 'XJ Technical Chat' started by dkavanagh, Aug 25, 2019.

  1. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    Hey, I could at least add a servo to adjust the mixture screw for me. (just joking, I don't trust something like that to not bugger up the screw, or a software error drive it hard into the seat)
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Why would he go to Finland? :p
     
    hogfiddles likes this.
  3. Minimutly

    Minimutly Well-Known Member

    Messages:
    1,746
    Likes Received:
    748
    Trophy Points:
    113
    Location:
    West Wales, uk
    Nowhere near it, but he will have the means to callibrate it!
     
  4. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    3D printed a support for the air pump. It purrs nicely when energized and creates suction at a nice level for this application.
    IMG_20201203_223936.jpg
    The lambda temp could get to 600 degrees (per the spec sheet), so the test chamber must be metal. Plastics I could print melt under 500 degrees. I'm working on a design in CAD. I plan to braze inlet and outlet pipes, and may as well braze the cap. I'm planning a part that can be built on a lathe that the sensor screws into and has a fitting to draw gasses in near the end of the sensor and an outlet (to the air pump) near the base of the sensor, hopefully to give the gasses the best chance of being measured since the sensor has openings at the end. I need to think about condensation and drainage. I'll probably let the air outlet be low and act as a drain as well. The air pump can expel any drops of water along with the air. Keeping the test setup powered on after shutting off the engine would allow water to clear (more or less).
     
  5. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    GOOD ONE!!
     
  6. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    i found it. the copper went up the pipe, the rubber hose went about 2 feet into a metal coffee can so any suck-back was still exhaust. worked on my VW, yamaha showed crazy wild swings
    and then i quit and went for a ride
    [​IMG]
     
    dkavanagh and jayrodoh like this.
  7. Minimutly

    Minimutly Well-Known Member

    Messages:
    1,746
    Likes Received:
    748
    Trophy Points:
    113
    Location:
    West Wales, uk
    Is that silicon sealer? If so don't use it, I read somewher it damages lambds sensors (or was that catalytic converters?)
     
  8. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    Minimutly likes this.
  9. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    I just wired and powered up my lambda controller and gauge. I did the calibration in free-air and the gauge read 22.4. Not sure what's expected there. I also used a Fluke temperature meter to measure temperature at the threads of the sensor, which came out to 150F. That's low enough for PLA which melts around 400F. I may just 3D print a test chamber and see how that holds up.
     
  10. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    air is about 21% O so that's close. i think if you rev it at all, your going to melt. print two
     
  11. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    My goal was to design something that could be primarily made on a lathe out of metal. If course, if I had a torch, I'd make something pieced together from parts that could be welded together. I know exhaust gasses can get a lot hotter, so I suppose 3d printing one would be primarily for prototyping the design. I'll have to fit my temperature probe into the chamber so that I can shut things down before I get a melty mess over the sensor!
     
  12. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    I love 3D printing. I is fairly fast to iterate and test a design. This took a little over an hour to print and has printed threads for the M18 1.5 threads of the O2 sensor. It threads in snugly as is preferable. I need to work on the holes for the air lines to improve their fit. I'll also thicken the wall around those holes so there is more overlap between the brass tube and the plastic. I was originally designing this to be easy to machine (and there's a separate cap that would be brazed on, but I'll 3D print it and super-glue it, or I could even melt it on with a soldering iron). I'll probably also add some mounting tabs to allow this to bolt on some spacers inside a case.
    IMG_20201220_095540414.jpg IMG_20201220_095509403.jpg IMG_20201220_095516053.jpg
     
  13. Huntchuks

    Huntchuks Well-Known Member

    Messages:
    951
    Likes Received:
    395
    Trophy Points:
    63
    Location:
    East Rochester, NY
    That is nifty. Dave, do you have that printer at home? What is the print resolution?
     
  14. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    I built this printer back in 2017, and did a number of upgrades to make it safe and run better.
    It's super cheap and there are likely better cheap printers now, but this still serves me pretty well. It can do .1mm layer height and has a .4mm nozzle.
     
  15. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Once you get it dialed in (and if you have the desire to take on a new hobby) get some green sand, a kiln, all the aluminum cans your neighbors will spare, and commence to casting.
     
  16. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    So many skills I'd like to learn, so little time (and spare $$s at the moment).
     
    hogfiddles, Franz and k-moe like this.

Share This Page