[s-cars] Fuzz logic vs adaptive learning

[Kirby Smith]

Two points:

a) The A'pexi learns what WGFV duty cycle to use to achieve its
commanded boost pressure (gauge) vs. rpm and gear, and throttle.  When
conditions change, it has to tweak what it knows.  Overboost occurs
temporarily under colder conditions, where it is more easily tolerated. 
Underboost occurs temporarily when it warms from cold conditions.

b) If we had a motronic that controlled the top of the WG, and could be
programmed by gear to make up for Audi's little embarrassing mistake in
tranny design, then I would agree with you wholeheartedly, rather than
just conceding that motronic is lower risk to the engine, but not to the
tranny unless OEM programmed.

kirby


QSHIPQ at aol.com wrote:
> 
> I understand the differentiation between FL and AL as the following...
> Adaptive learning (AVC-R) means you have a set of parameters you want.  The
> controller applies those parameters and says no or yes to them as presented.  So the
> map is presented based on the exact number of variables you can program, it's
> map is entirely based on exactly that number of inputs.  "Adaptive" means it
> does have the ability to give less or more of a given parameter, but can't fill
> in an unassigned value.
> 
> Fuzzy Logic (HKS EVC-IV, Profec A) learning means you have a set of paramters
> you want, and FL will say yes or no and come back with an acceptable
> parameter based on desires and other inputs.  FL is capable of assigning values to a
> map far in excess of what you may be able to program.  In other words, you give
> it guidance and it can fill in anassigned values to get you there.
> 
> The biggest risk to adaptive and FL controllers IMO, is exactly where they
> have the highest use, CO.  Either can be programmed at a specific altitude and
> compressor efficiency, but both controllers will create a bad engine
> environment as soon as altitude/press changes affect turbo CE and engine VE.  In other
> words,  AL/FL controllers aren't desireable in an environment that has a high
> variance from "standard atmosphere"  (point in time programming).  They also
> require that ANY change to the hardware (engine tweeks that affect VE or CE)
> require a "relearn/reprogram".
> 
> As such, it's my claim that the best controller is still motronic.  Since
> AVC-r has no input to MAF it's not a Mass of air based (motronic) profile.  And
> in order for it to be a true speed density system, it requires feedback loop
> with MAP (read it has no O2 input).   Motronic has MAF, MAP and O2, hence can be
> either a MAF or speed density computer (yup Minhea I won't go there:)   Which
> means that any significant change in altitude will not be a recognized input
> to the boost profile of the external controller.  I see that as bad, nee,
> potentially really expensive.
> 
> WRT motronic, it does have some AL built into it, since it can learn that you
> are at altitude and change the baseline fuel on startup (hi alt, low temp)
> and can enrich fuel mixture if knock is detected.  Knock control itself is a
> "learning" mode, and is adaptive in the 20vt (fuel and driving conditions) and
> has really been around since the mac 11 (premium vs regular fuel tables).
> 
> Integration of boost control with engine management is crucial, and is really
> what gives Motronic the massive edge over a standalone controller.  HKS has
> made several attempts over the years to integrate boost control with other
> controllers, but has pulled many off the market because of the complexity of
> integration without direct interface with the engine management computer.  Profec A
> (fuzzy logic controller) has been discontinued, I suspect from reading the
> other boards, from the exact problem above.   My thinking is, that makes any
> argument that "software" in a controller is better or can be better than
> motronic:  moot.  From what I've read to date in terms of "performance" clearly
> indicates to me that the WGFV in the motronic is a problem.  Once that hardware has
> been addressed, I really believe the software already has all the makings for
> one of the best boost controllers on the market today.  AND you already own
> the darn thing.
> 
> To make the claim an external boost controller is better than motronics boost
> controller, it needs minimally the same inputs as motronic.  Then it's still
> not interfaced with the ECU like motronic boost control.  Then, if you finally
> get the controller to have the same inputs and interfaced control, you either
> have a redundant set of sensors, or you have just built a better motronic
> box.  We already know a lot about that box under the passenger foot.  Why not
> just make it better at it's job?
> 
> Scott "more FL" Justusson
> QSHIPQ Performance Tuning
>