Author Topic: PV AutoTune basic  (Read 1006 times)

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Offline dwjohnson

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PV AutoTune basic
« on: December 19, 2019, 06:29:26 PM »
 I had some thoughts on this feature and looking for any input as to whether I'm far off or not.
        I understand it seems that most agree the narrow band sensors are more accurate than wide band, but only within their range. Well if the entire map in auto tune is changed to 14.7 or closed loop mode, it would appear to me that the VE results from the stock O2 sensors would likely be as close to perfect as you could get.
       I understand the bike may not run/feel best during these auto tune sessions, especially when performance mods would dictate a much richer mixture, but afterwards, when the values are exported and map is restored, wouldn't it stand to reason the VE values then would be closer to correct? And then, as long as the A/F values are appropriate, the bike should run and perform very well?? If in case it didn't, would you suspect the A/F numbers, the VE numbers, or still something else entirely different?   
   

Offline Coyote

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Re: PV AutoTune basic
« Reply #1 on: December 19, 2019, 06:49:22 PM »
Well if the entire map in auto tune is changed to 14.7 or closed loop mode, it would appear to me that the VE results from the stock O2 sensors would likely be as close to perfect as you could get.

If that were the case, all the dyno guys would just tune with narrow bands, right?  :wink:

I was promised Monsoons.

Offline rbabos

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Re: PV AutoTune basic
« Reply #2 on: December 20, 2019, 05:59:03 AM »
My experience is the NB sensors have a limited range and do a fine job in those areas. Beyond that, the only way you can dial it in is with WB sensors.
Ron

Offline Karl H.

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Re: PV AutoTune basic
« Reply #3 on: December 20, 2019, 06:58:09 AM »
The basic question is whether the volumetric efficency (VE) is influenced by AFR. There is no doubt that the VE is influenced by exhaust gas dynamics. And while AFR influences exhaust gas dynamics it influences VE. Right?

Karl
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Offline Burnout

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Re: PV AutoTune basic
« Reply #4 on: December 23, 2019, 09:12:21 AM »
First of all, overthinking.   

What is the benefit of a "perfect" VE table?

Also few motors I have tuned would be happy with a flat AFR table, Best power is at 12.5, Idling at 14.7 is not always possible.

It is possible to adjust the VE table or the AFR table and accomplish the same result.

Closed loop will reel in an "incorrect" VE table, as closed loop tries to follow the AFR table.

Remember you are looking at a process the VE table is on the input side (predictive), and AFR (Lambda) is measured on the output.
They don't call me Ironhead Rick just because I'm "hard headed"

Offline jjdalynh

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Re: PV AutoTune basic
« Reply #5 on: January 11, 2020, 03:51:11 PM »
it's probably a rare motor that will be ok running at 14.7 in the areas outside of the cruising range for long enough to get good data to tune VE.  as stated, even at idle a motor is probably not going to be happy at 14.7, and certainly at WOT is not going to be happy at all.   Certainly the desired AFR is going to have an effect on the VE.  TTS (as an example) has the facility to allow you to tune with both WB and NB at the same time, using your desired AFR (or closer to final) table of both closed loop and open loop AFR values.  In the closed loop region, the NB readings will have a higher weight than WB even though the WB can read those regions.  the expectation of a motor to live at a  closed loop friendly 14.7 AFR at WOT for any significant time is not likely.

Offline rbabos

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Re: PV AutoTune basic
« Reply #6 on: January 12, 2020, 03:58:23 AM »
I've never like BASIC autotune in PV. It sets the clb to 700 and -4 degree timing. When you are done tuning and revert back to the cal the ve is all wrong to the new base clb and timing. I was seeing up to 12% error in the integrators after setting the cal back.  A better tune can be had tuning actual clb of your choice and full timing after a couple of basic autotune runs and using MyTune with PV logs. Remember the 14.6 is an O2 switch, not the actual  afr you are tuning. That would be from the clb tables for actual afr.
Ron

Offline remington007

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Re: PV AutoTune basic
« Reply #7 on: January 12, 2020, 07:00:23 AM »
I have tried advancing the timing tables 4 degrees and then doing a basic auto tune, carefully staying in the cruise and light load area. The VE tables were quite different.

Offline rbabos

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Re: PV AutoTune basic
« Reply #8 on: January 12, 2020, 10:12:20 AM »
I have tried advancing the timing tables 4 degrees and then doing a basic auto tune, carefully staying in the cruise and light load area. The VE tables were quite different.
Yes, I was doing the same as in adding plus 4 and ending back to even in basic autotune config mode. I also learned to remove all 127 cells in the cal or it will nag you to death with unneeded or wanted scaling as most of mine were in decel areas . If new ones showed up in load areas, then I scaled.
Ron