[s-cars] Re: Motronics MAP - some fuzzy logic included

Thu Jan 22 17:22:51 EST 2004

My 2 Eurocents: a Motronic could be reprogrammed in order to control a 
stepper motor, but the problem is that this would require program code 
changes (as opposed to lookup map changes, which is done with regular chip 
tuning) and it's not that easy. Not impossible but still, what's more 
precise to a stepper motor rather than a FV???? AFAIK if everything is 
programmed correctly, boost will follow the exact curve one has programmed 
inside the chip...

Mihnea

At 13:59 22/01/2004 -0800, Joseph Pizzimenti wrote:
>My 2 cents:
>
>The next step up from the VMAP development would be to
>allow for the ECU to control a stepper motor or
>quicker solenoid, allowing for more precise control.
>
>Come on, Feico, I know you can do it.  =)
>
>As for me and my HKS electronic dial-a-boost, I just
>keep it at 20psi on pump gas and 22 on the good stuff.
>  Still have to get it on a dyno and reflash the ECU's
>fuel and ignition maps, hopefully that will happen
>within the next couple weeks.
>
>Joe
>
>--- Robert Pastore <rpastore at animalfeeds.com> wrote:
> > Scott:
> >
> > Generally agree with all you've said WRT boost
> > controllers; several years
> > ago I invested in the Apexi AVC-R, and wound up
> > removing it after I learned
> > how to write a boost map for the motronic.
> >
> > But I disagree that the fuzzy logic (FL) is what is
> > putting your engine at
> > risk.
> >
> > As I understand it, the FL is looking at the delta
> > between the actual boost
> > experienced (as per the MAP sensor), and the desired
> > boost (per the
> > programmed boost profile), and then adjusting the
> > controller's output to the
> > actuator to minimize that delta, whether it be
> > changing the duty cycle of a
> > FV, or a stepper motor.   If you want more on how it
> > works, I think Julian
> > Edgar from Autospeed did a great job of explaining
> > it in the series of
> > articles on the intercooler/water injection
> > controller they built.
> >
> > The integration and interaction of boost control
> > with the ignition and fuel
> > control of motronic provide a much more
> > sophisticated management system than
> > an aftermarket controller can provide. Just like you
> > said, it is a function
> > of the number of inputs, data points on the maps,
> > and the tools the
> > controller can control as outputs.   The boost
> > controller can only vary
> > stepper motor or FV duty cycle. The motronic can
> > reduce ignition timing,
> > dump extra fuel to cool the cylinder, and shut power
> > to the WGFV to reduce
> > boost, all as safety measures to protect the engine.
> >
> > I see the primary shortcoming of the boost control
> > system on the AAN to be
> > bottom chamber only boost control (the WG is  slow
> > to react and leaks boost
> > into the exhaust via the WG valve-to-guide
> > clearance),  as opposed to the
> > earlier Audi (and most aftermarket boost controller)
> > top chamber control
> > systems.  I think the change was probably due to the
> > regularity with which
> > WG diaphragms tore under the earlier system, because
> > the pressure delta
> > across the diaphragm is greater, thus faster acting
> > and more violent.  The
> > change probably solved a warranty/durability issue,
> > but was IMO an
> > engineering compromise that resulted in less actual
> > boost control, [
> > strictly my theory] and the creation of "overboost"
> > as a great marketing
> > gimmick to describe the period of time it take the
> > inferior actuator system
> > to reel in a rapidly spooling turbocharger.
> >
> > The other problem is the speed of the stock WGFV.
> > It is slow and soft.
> > It is interesting to see that ECS has taken this pig
> > of a valve ( or
> > derivative thereof), and marketed it as an upgrade
> > to the b4 s4 crew.   It
> > seems that the B4 s4 has a faster active WGFV, so by
> > putting in a slower
> > one, boost levels climb and you go faster.
> >
> > rgds,
> > Bob
> >
> >
> > -----Original Message-----
> > From: QSHIPQ at aol.com [mailto:QSHIPQ at aol.com]
> > Sent: Thursday, January 22, 2004 1:38 PM
> > To: CaptMagu at aol.com; FvAMI at aol.com;
> > pizzoman at yahoo.com
> > Cc: s-car-list at audifans.com
> > Subject: [s-cars] Re: Motronics MAP - some fuzzy
> > logic included
> >
> >
> > Let's explore this a bit Hap.  Computers can't
> > really learn, these
> > controllers you speak of are referred to as fuzzy
> > logic boost controllers.
> > Fuzzy logic
> > as applied to a boost controller will only be as
> > good as the S car Motronic
> > when it can accept as many variables in the boost
> > profile.  Currently we
> > have
> > MAP, engine temp, dual knock, throttle position,
> > altitude and CAT.  IMU,
> > none of
> > the boost controllers on the market can account for
> > these variables.  They
> > can *assume* their is something wrong within the
> > parameters of the fuzzy
> > logic
> > program, but it can't *identify* it if it's not an
> > input.  Then what
> > happens?
> >
> > Well it can't code anything or flash you a ck engine
> > light to advise you
> > that
> > the reason for fuzzy logic interrupt to a boost
> > profile is for a specific
> > reason.  So, by definition fuzzy logic can't *learn*
> > anything.  It can only
> > sense, via it's specific and only inputs, that it
> > can't give you what you
> > have told
> > it to.  So, one could argue that a fuzzy logic could
> > be better than a non
> > fuzzy logic external boost controller (see below),
> > but I'm not at all
> > convinced
> > that this is even close to a Motronic boost
> > controller.
> >
> > The best part of ANY external boost controller could
> > be argued to be the
> > stepper motor function.  It's quick and it's
> > accurate and it's failure rate
> > is
> > almost nil.  That doesn't at all equate to the
> > controller itself being
> > better,
> > only the mechanics of the valve actuator of boost
> > being better.
> >
> > Further, I'd ask the question in "fuzzy" logic, how
> > does the controller
> > learn
> > that you've fixed or changed some parameter to allow
> > 'full' boost again.
> > Does it continue to apply your desires, then accept
> > a lower value?  That
> > could be
> > scarey.  When you climb into the mountains (by
> > definition a boost reduction
> > in the motronic >10,000ft = no WGFV function),
> > what's fuzzy logic think of
> > that?  I don't believe it thinks at all.  I
> > personally believe fuzzy logic
> > boost
> > controller are looking ONLY for turbo surge line as
> > the indication of
> > profile
> > adaptation.  Add in a limited number of inputs, it's
> > primary adaptation is
> > surge line based.  Even then, by my thinking, it
> > will fail at it more times
> > than
> > it will succeed.  Why?  Cuz FL have to constantly
> > learn.
> >
> > I argue that if indeed this is true, then I'd rather
> > have a manual boost
> > controller that let's me do the fuzzy logic (fair
> > and reasonable knobben
> > dialer
> > argument).  Cuz my argument is that a FL boost
> > controller is constantly
> > putting
> > your engine into the danger zone, by definition, it
> > has to to apply FL to
> > it's
> > adaptation.  Your hi and low settings are based on
> > your estimation, not
> > based
> > on the actual engine function or the parameters
> > motronic is conservatively
> > monitoring.
> >
> > Point of reference 012204, I make the claim that FL
> > boost controllers are
> > still second to Motronic in terms of input
> > parameters and safety in
> > attaining
> > boost levels.  My suggestion is to take some of this
> > seemingly unlimited
> > budget
> > dollars and getting yourself a good motronic
> > programmer to really explore
> > options within the motronic box.  Bosch made a darn
> > good integrated boost
> > controller, it needs a little tweeking to make it
> > great.  IMO, it's within
> > the
> >
>=== message truncated ===
>
>
>=====
>-------------------------------------
>The following statement is false.
>The preceding statement is true.
>-------------------------------------
>
>__________________________________
>Do you Yahoo!?
>Yahoo! SiteBuilder - Free web site building tool. Try it!
>http://webhosting.yahoo.com/ps/sb/
>_______________________________________________
>S-CAR-List mailing list
>S-CAR-List at audifans.com
>http://www.audifans.com/mailman/listinfo/s-car-list