The effects of AFV on open loop areas

[1FSTRK]

Quote from: glens on Saturday, September 24, 2011. 01:15:15 AM.
Sporty, it's relative simple.  Really.  And the colors are immaterial.

In closed-loop operation, the ECM drives the fuel high, then low, then back again, then back again...  It monitors itself by reading the O2 sensors tracking the swings.  It zeros in, not on the specific AFR, but on the narrow range centered upon that AFR.  Over time as necessary corrections are noted, they're kept track of and utilized so as to keep the fueling swings nicely centered on the target output of the O2 sensors.  And these corrections can successfully carry over to the areas of operation which cannot be self-monitored via the simpler, faster, and cheaper type of O2 sensor we have in use: both wide-open throttle and sudden throttle transitions throughout the operating range, along with cold startup, to name a few.

This is an excellent method of maintaining the tune in the face of changing circumstances.  Circumstances like differing fuel make-up/quality; differing injector response over time; differing fuel pressure over time; etc.

A carburetor has better ability to adapt to running variations than does open-loop-only EFI.  And a carburetor can't hold a candle to EFI which is running with a self-contained system of checks and balances (closed-loop operation).

The only real drawback is that all the closed-loop running parts must work and work together in harmony.  Sometimes that doesn't happen, though, and the conventional wisdom says to just bypass closed-loop operation altogether when problems arise.  Some folks never even bother to look for any problems, they just step back several years in technological time as a matter of course.

The above quote from glens on the whittlebeast thread got me wondering about how we could use the AFV effect on open loop areas to our advantage. These are my first thoughts on it and it would seem that with the minds that are on this site that we should be able to develop a working process or two to try on the more radical builds. I would like to try this if it sound like it is worth the test time. What do the tuners think?

1. V-tune and auto-extend including optimizing the timing
2. Dyno tune the top end portion of the maps for best power and record the AFR with the dyno.
3. Ride the bike with a known fuel long enough to allow it to generate the AFV
4. Return to the dyno and rerun the top end while recording the AFR with the dyno
 
Wouldn’t the difference in AFR between test 2 and test 4 reflect the AFV. If so could we apply that percentage to the open loop area and reflash with the new cal. The check would be to run the bike again to allow AFV to generate and then rerun on the dyno to see if it now reproduces the run and AFR from the run in step 2. This should set things up so that as AFV changes in closed loop they affect the open loop areas in a positive manor. This may be overkill on most bikes but if the process worked it could help to fine tune the more modified and high output bikes.

[BVHOG]

First off, the auto extending of the ve tables is a guess, so you can rule that out immediately, it may work in some instances but more often then not it will be inaccurate. 
I know what you are getting at here but wouldn't it just be more realistic if by software manipulation the afv did not affect the open loop areas at all?

[wurk_truk]

What are you thinking and tting to accomplish here?  I don't think your head is toyally wrapped around AFVs and how they function.

Two things...  In closed loop they function differently than the open loop sections that get effected.  Closed loop will lean or richen.  Open loop portion of a  closed loop tune will only richen.

So with this...  You wanna do what?  Be more clear.

Sent from my DROIDX using Tapatalk

[1FSTRK]

I may be all wrong here that is why I started the thread.
If the AFV drives the open loop area richer after the dyno tune it will be too rich. If I can measure the amount that it drives it too rich I can compensate for it in the cal then the next time the AFV should drive the open loop area to where it was tuned on the dyno instead of too rich.
If tuned with the best gas this should let the AFV help the open loop area richen for bad gas  just as it helps the closed loop area without driving it to rich when you fill up with the good gas.

[hrdtail78]

Are you talking open loop or WOT.  What I understand is that AFV do affect OL but the farther is gets away from a CL cell.  The less affect it has.  So, if 80kpa is the high limit, 100kpa has 90kpa and 95kpa inbetween.  So how much it affects 100kpa (if at all) has to be known before we could try and work with it the way you are saying.

[1FSTRK]

Wouldn't  recording the before and after affects on the dyno at 90,95 and 100 kpa give that information.
We know it is coming into play and we have no way to see or alter it directly with the present software so I'm just think about how to monitor it and reverse engineer it into the cal to get the best results possible

[glens]

I'm pretty sure the 100kPa gets effect out of this mechanism.  I'm not so sure the effect is only ever richer; I believe it goes both ways in our system.

If the AFV drives the open loop area richer after the dyno tune it will be too rich. If I can measure the amount that it drives it too rich I can compensate for it in the cal then the next time the AFV should drive the open loop area to where it was tuned on the dyno instead of too rich.

And where would you be before that might happen, too lean?  What if a fuel-pulling effect takes place instead?  Way too lean then?

There's no "the AFV".  There are multiple AFVs per cylinder.  Per authoritative statements there are various numbers of them in different calibration levels (I'm thinking more in later ones).

If you've tuned on a dyno, the relationships between closed-loop areas and always-open-loop ones is established as correct.  If the AFVs do anything either direction from that as a result of whatever (valid) reason they make changes, you want that initial relationship to remain, which you won't if you pre-bias the system somehow.  Something like a different fuel blend causing an effective VE change down low (one way or the other) is good cause for a similar change up high because it's the same fuel running both places.  Whatever relationship there is between somewhere closed-loop and WOT would ideally remain when AFVs do their thing over time.

I'd strongly caution against messing with it like you're contemplating.  Best would be to get all the VEs calibrated in proper relationship to one another at some point in time with the AFVs sitting right at 100% at that time if possible.  I realize that'd take a bit of faith, but implore you to trust me.  Heck, things change a few percent from day to day even on the same tank of fuel; you'll never get it all to stay exactly the same over any length of time.  Get things as close as you can and let the system do its work.

[1FSTRK]

OK so I just reread Steve’s post #423 on Andy’s thread and I guess I either misread or misremembered that post. I know that reading that thread is what got me thinking about all this.
Sorry for wasting time and forum space. I just have always needed to understand how things work and tend to obsess until I think I do.
Thanks to all that replied 

[glens]

I sure don't think you'd need to apologize about anything regarding this thread.

[Sporty 48]

1FSTRK,
Why not do a careful experiment to test your ideas?
Toasting a motor is the biggest fear, so go carefully.
If you have the equipment and a little time, why not test. You might come up with something unexpected. Let us know.

[strokerjlk]

1. V-tune and auto-extend including optimizing the timing
2. Dyno tune the top end portion of the maps for best power and record the AFR with the dyno.
3. Ride the bike with a known fuel long enough to allow it to generate the AFV
4. Return to the dyno and rerun the top end while recording the AFR with the dyno

1.Dyno tune all ve's
2. Ride the bike with a known fuel long enough to allow it to generate the AFV
3. Return to the dyno and rerun the top end while recording the AFR with the dyno

this has all been done on a few dynos.
not only does the AFR'S change but so does wot HP/TQ

[Steve Cole]

What's going on in these cases where things are coming in to play and changing are problems that should have been fixed prior to tuning. I can run and have run our 120R test bike, several times, over the past 7500 miles of testing and it runs Closed Loop just like a stock bike and it makes within +/- 1.5% of what it did when it first came off the dyno. So it's not a matter of it doesn't work, it's a matter of spending the time to make sure each part of the system is working as it should to start with.

[04FLHP]

1. V-tune and auto-extend including optimizing the timing
2. Dyno tune the top end portion of the maps for best power and record the AFR with the dyno.
3. Ride the bike with a known fuel long enough to allow it to generate the AFV
4. Return to the dyno and rerun the top end while recording the AFR with the dyno

1.Dyno tune all ve's
2. Ride the bike with a known fuel long enough to allow it to generate the AFV
3. Return to the dyno and rerun the top end while recording the AFR with the dyno

this has all been done on a few dynos.
not only does the AFR'S change but so does wot HP/TQ

It seems if the VE tables in the closed loop area were not correct and the VE at WOT was set correctly on the dyno then that would account for the AFV changing the WOT dyno run after time.
If the closed loop VE tables are correct at the time of the dyno run then the AFV should follow throughout the table.

[glens]

It seems if the VE tables in the closed loop area were not correct and the VE at WOT was set correctly on the dyno then that would account for the AFV changing the WOT dyno run after time.
If the closed loop VE tables are correct at the time of the dyno run then the AFV should follow throughout the table.

Or maybe neither were set "correctly".  That is to say, maybe the plumbing/sensors function together just fine and the dyno operator either has such faith in their exhaust gas acquisition and/or O2 sensor systems that they tend to quibble over 0.1 AFR and set it at odds with what the ECM wants to do.  Naturally, in such a case, the ECM in closed-loop will "dick with" what they've done.

[Hilly13]

What's going on in these cases where things are coming in to play and changing are problems that should have been fixed prior to tuning. I can run and have run our 120R test bike, several times, over the past 7500 miles of testing and it runs Closed Loop just like a stock bike and it makes within +/- 1.5% of what it did when it first came off the dyno. So it's not a matter of it doesn't work, it's a matter of spending the time to make sure each part of the system is working as it should to start with.

The last sentence is the first place to start.......

[1FSTRK]

1FSTRK,
Why not do a careful experiment to test your ideas?
Toasting a motor is the biggest fear, so go carefully.
If you have the equipment and a little time, why not test. You might come up with something unexpected. Let us know.

I don't think there is any chance of toasting the motor because the tune will never be that far off when doing this test.
Doing this right is time consuming and the dyno time cost money so it is not worth it if none of this works the way I thought it did. glens and Steve have explained the things I misunderstood on how AFV is applied so this test seems to be senseless now.

[1FSTRK]

It seems if the VE tables in the closed loop area were not correct and the VE at WOT was set correctly on the dyno then that would account for the AFV changing the WOT dyno run after time.
If the closed loop VE tables are correct at the time of the dyno run then the AFV should follow throughout the table.

Or maybe neither were set "correctly".  That is to say, maybe the plumbing/sensors function together just fine and the dyno operator either has such faith in their exhaust gas acquisition and/or O2 sensor systems that they tend to quibble over 0.1 AFR and set it at odds with what the ECM wants to do.  Naturally, in such a case, the ECM in closed-loop will "dick with" what they've done.

I don't think 0.1 AFR will show up as a loss of HP and TQ on a WOT dyno run and I know you can't feel it when riding. 

[glens]

I agree.  I was merely trying to make a point.  I see folks who are tuners posting here who seem to always have problems with closed-loop operation.  And I've seen some mention tuning to 14.3 instead of 14.6 because they were using an ethanol blend fuel which has a stoich AFR lower than gasoline.  Regrettably I don't recall off hand whether they're same folks or different.

What I've never heard anyone mention is how they're deriving that "14.3".  Most of the AFR measuring stuff I've seen is hard-coded to show 14.6 at stoich.  But stoich is stoich, so whether it's actually 14.3:1 at the moment, or 14.6:1 at the moment, the meter will show "14.6" if it's stoich.  If they then take this meter and tune relative to "14.3" the old-school way of setting all the AFR tables to a single value like 13.5 and making the VE tables put out 13.2 on the meter, it's likely to cause troubles trying to put the bike into closed-loop afterward, because what they'd thought was "14.3" was in fact the equivalent of "14.0" with their "14.3" fuel.

Now you say "I doubt .3 AFR would show up as a loss of HP/TQ or that you could feel it while riding".  I don't know if it would and I don't know what kind of HP/TQ loss they are even talking about.  1 or 2 percent?  10?

The scenario I put forth just above would by itself cause AFVs of nominally 102% 98% right off the bat, which when carried to WOT would put the mixture 2% rich lean.  Would that cause a (repeatably) measurable loss of HP/TQ?

I believe there can be combinations of equipment that make some areas of closed-loop problematic, don't get me wrong.  But every combination that comes through their doors?  I'd have to say that something ain't happening right, and it seems to be fairly consistent for some.

Granted, I tend to hang around here in spurts.  It's been probably most of year since my last one.  Perhaps some of this stuff has gotten discussed in the mean time and I missed it.  If that's the case, kindly point me to the discussions.  If it's not the case, well, now's about as good a time as any to talk about it, what do you say?

[blusmbl]

That's exactly why tuning with lambda instead of AFR makes so much sense. 

[whittlebeast]

1FSTRK,
Why not do a careful experiment to test your ideas?
Toasting a motor is the biggest fear, so go carefully.
If you have the equipment and a little time, why not test. You might come up with something unexpected. Let us know.

All it would take is a PowerVision with the wideband option running both the stock narrow bands for closed loop and the widebands on the same bike and a quick experiment.  In testing with the wideband so far, I am seeing that the Sportys have a hell of a time holding AFR over time.  Time being 45 min or so.  This is stuff that will be tough to catch on a dyno.

It makes me wonder if this is why Harley goes to so much trouble to feed hot  air to the air cleaner.  This  may have to do with getting the intake manifold up to temp to keep the fuel off the surface.  This may be all related to why a motor needs so much AE when cold.

Beast

[1FSTRK]

1FSTRK,
Why not do a careful experiment to test your ideas?
Toasting a motor is the biggest fear, so go carefully.
If you have the equipment and a little time, why not test. You might come up with something unexpected. Let us know.

All it would take is a PowerVision with the wideband option running both the stock narrow bands for closed loop and the widebands on the same bike and a quick experiment.  In testing with the wideband so far, I am seeing that the Sportys have a hell of a time holding AFR over time.  Time being 45 min or so.  This is stuff that will be tough to catch on a dyno.

It makes me wonder if this is why Harley goes to so much trouble to feed hot  air to the air cleaner.  This  may have to do with getting the intake manifold up to temp to keep the fuel off the surface.  This may be all related to why a motor needs so much AE when cold.

Beast

I do not own any of the equipment you mentioned.
I see no problem with a competent dyno operator with the proper equipment performing this test and getting accurate data, but as I said, I no longer believe this particular test will provide any useful or new information.
My testing and your Sportster testing would not be comparable because of the numerous differences and totally uncontrollable variables.
I do not see where any of the data you have gathered with your systems is complete enough or repeatable enough to draw any accurate conclusions as to the root cause of the changes you report. To continue to record and view data with different software has not enabled you to accurately conclude if what you are seeing is caused by the original Delphi code having a flaw, or if the ECM is doing what is was programmed to do in response to something that is off in the mechanical design of the motor or exhaust or some other hard parts. Without some way of identifying the root cause how do we know if we should redesign the EFI system to match the motor or redesign the motor so it will work with the EFI.   

[blusmbl]

It makes me wonder if this is why Harley goes to so much trouble to feed hot  air to the air cleaner.  This  may have to do with getting the intake manifold up to temp to keep the fuel off the surface.  This may be all related to why a motor needs so much AE when cold.

The restrictive air cleaner is there to help meet EPA drive-by noise regulations and to prevent water intrusion.  The fuel is going to be on the intake manifold walls regardless of manifold temperature, it looks like a bloodbath in there when the engine is running.

[Sporty 48]

I love this forum.
Guys propose perfectly reasonable suppositions, others tell them why they will not work and then no innovation, no experimentation is attempted.
B. S. (male cow poop)
I have a Forcewinder, the original long intake pipe with a Unique Metal Products (UMP) desert racing air housing with a UNI air filter. The UMP housing is the first Harley housing he made. I love it. Looks Great! Had to send the housing to UNI for the filters because I had to modify it to fit with the roll bar. Imagine a diesel filter (they use a lot of air) with a spin to the intake air to separate the particles (dirt) out of the intake air. I get turbulence, cool air and when I go to the desert this winter, no sand.
That my friends is innovation. Some ask if it is a turbo, I say no I just want lots of clean cool turbulent air.
My bike screams, for a Sportster.

[mayor]

Some ask if it is a turbo, I say no I just want lots of clean cool turbulent air.

are you sure you want turbulent air?     I think what you gain by using a longer throat on the intake tract is tuned airflow....which is likely the opposite of turbulent air flow. 

[cts1950]

I know this has nothing to do with Harley's. GM with their vortec head design wasn't that designed to increases combustion chamber turbulence for better fuel air mixing and flame front  control? It sure made a difference in the old 350 engine.