In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Well, my new toy is finally in my hands.

Discussion in 'Chainsaws and Power Equipment' started by Gill, Jun 17, 2016.

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  1. MasterMech

    MasterMech The Mechanical Moderator

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    Depends on what you consider the full extent to be. The system adjusts itself to attain maximum performance of the engine. And in my experience, it does that quite well along with the much improved cold start characteristics of the engine. But there are not as many sensors at work here as you might think. The only (external) inputs are temperature and rpm. And a switch to indicate wide open throttle. The fuel side of the system operates largely similar to the old game of "hot and cold". Make an adjustment, better or worse? Repeat. I don't know how it adjusts ignition timing but I would imagine it's a pre-determined table based on engine temp and load (rpm). Ignition modules with a built in advance curve are not unique to the AutoTune and M-tronic saws either. They've been around quite awhile already.
     
    MasterMech, Jun 22, 2016
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  2. Boomstick

    Boomstick Banned

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    Some parts swapping(mtronic) from a well run in motor/powerhead to a brand new one on a dyno would show the difference if there is one.
    If it did have a break in procedure a dyno would show it on the run in/broken in powerhead.
     
    Boomstick, Jun 22, 2016
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  3. Andyshine77

    Andyshine77

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    The Mtronic system is much more simple than some make it out to be. The system simply looks for maximum rpm under load. Too lean you loose rpm's, too rich you loose rpm's. That's it, no temp sensor or anything else. It's a crude yet very effective system. Most saws already have a ignition advance, that is nothing new. The Husqvarna system is a bit more advanced, as it senses throttle position, rpm and temperature. It also reads fuel octane, how I don't know.

    Sent from my HTC One_M8 using Tapatalk
     
    Andyshine77, Jun 22, 2016
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  4. MasterMech

    MasterMech The Mechanical Moderator

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    Fuel octane? Thats one I would be curious to know how it's done as well. Stihl claims to account for fuel quality which of course is easy if you are always shooting for max rpm under load. ;)

    From Sthl's website:

    Now how would it do that without a temp sensor? Just a simple thermistor built into the ignition module would do the trick.
     
    MasterMech, Jun 22, 2016
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  5. Andyshine77

    Andyshine77

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    It just remembers the last setting. Again the Mtronic system is very simple.

    The actual readout on the Husqvarna software provided quite a bit of info. Run time at idle, part throttle and full throttle. Engine temp, fuel type, engine rpm's. Even carb fuel setting from 0 to max available. Pretty cool. How they get fuel octane is beyond me.
     
    Andyshine77, Jun 22, 2016
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  6. Horkn

    Horkn

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    Some cars and the modern efi 2 stroke sleds do it with a knock sensor.
     
    Horkn, Jun 22, 2016
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  7. Andyshine77

    Andyshine77

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    Correct, but the AutoTune system doesn't have a knock sensor, or 02 sensor, so I have no idea how they get the octane.
     
    Andyshine77, Jun 22, 2016
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  8. Andyshine77

    Andyshine77

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    Correction.... the software doesn't show octane, which make sense, sorry I remembered incorrectly. Here is a video I found that shows the information from the AT system.

     
    Andyshine77, Jun 22, 2016
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