[s-cars] Fuzz logic vs adaptive learning

Mihnea Cotet mik at info.fundp.ac.be
Sun Jan 25 19:38:31 EST 2004


Kirby,

The Motronic uses a 10x16 points boost map, as well as a 10x16 points WGFV 
duty cycle map. The boost values are "target values" and the FV duty cycles 
are set to reach the desired boost levels with a given WG spring tension.

Programming the Motronic for top feed control sounds easy enough to me as 
long as a WGFV (or sort of) is still there, it's a matter of about one hour 
of real-time tuning with my on-line emulator plugged into the ECU. Let me 
know if you feel like experimenting this spring :-))))

HTH,

Mihnea

At 16:12 25/01/2004 -0500, Kirby Smith wrote:
>So, is the Motronic programmed with WGFV duty cycle, or with boost
>levels to be achieved such that the Motronic continuously re-learns what
>duty cycle to use as conditions change.
>
>For inversion of duty cycle to top feed, an external power transitor
>would work.  However, if the Motronic can't learn to change duty cycle
>to get the desired boost, then a lot of experimentation and
>reprogramming would be needed.
>
>kirby
>
>
>QSHIPQ at aol.com wrote:
> >
> > Kirby:
> > Comments inserted
> > In a message dated 1/24/2004 1:25:03 PM Central Standard Time,
> > kirby.a.smith at verizon.net writes:
> > 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.
> >
> > I only speak to the difference between Adaptive and Fuzzy logic.  Adaptive
> > can only plot in the known points, if you have 16 options to program in 
> each
> > gear for instance, it can only "learn" 16 boost values (based on desires vs
> > inputs).  Fuzzy logic is capable of much more.  You can program 16 
> 'desires', and
> > FL cannot only learn and assign values to those 16, it can take unnassigned
> > values between the 16 and assign a boost profile to them.
> >
> > >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.
> >
> > Again, not a hardware problem.  Mac 11 used a top feeder AND Mac 11/14 
> used a
> > first gear lower boost (the wire is snipped if it's a 5spd).  I would also
> > venture to say that no FV boost intervention in first gear is probably 
> better
> > than *any* control.  Let the turbo ramp itself, even a k24 won't reach 
> close to
> > a maximum boost map profile in first gear without FV assistance 
> IME.  Want a
> > top feeder valve?  You are darn close to just inverting the values 
> assigned to
> > a bottom feeder.  Again a software issue.
> >
> > Scott J
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