[Diy_efi] Re: Diy_efi digest, Vol 1 #341 - 12 msgs

[Bill Washington]

Eric,
    The oscillation to rich is not an anomoly in the system, it is a 
requirement of the CAT. I read recently somewhere that although the CAT 
can cope with lean operation it requires a rich pulse every 1-2 seconds, 
IE they don't like either continuous lean or continuous rich operation.
    That being said, mine oscillates continuously at a much faster rate 
than that (I'm guessing ~5 times a second).

Regards
Bill





>--
>
>Message: 4
>To: diy_efi at diy-efi.org
>Date: Sat, 2 Nov 2002 11:21:39 -0500
>Subject: Re: [Diy_efi] New to list, have a question about speed density and turbos
From: Eric D Byrd <klox at juno.com>
>Reply-To: diy_efi at diy-efi.org
>
>First, I have studied basics of feedback control, and if the system
>oscillates, there are ways to achieve tighter control with less tendency
>to oscillate.  I would speculate that the closed loop methods currently
>in use themselves make use of the most primitive control algorithms,
>because of commercial/mass production reasons.  Second, I've seen how a/f
>meters, the ones with led lights, operate, and they seem to oscillate
>with a period much faster than 2 seconds, which leads me to suspect that
>a better wideband sensor might be used to better effect, with a more
>effective control algorithm with much less oscillation about the target
>point.  Third, if the answer were obvious to me, I would not have asked
>the question.  At this point I don't even remember what the question was;
> in fact what I remember is that I suggested a good final goal would be
>to try to create a closed loop system of fuel control under boost with a
>wbO2 sensor.  Not at all a ridiculous idea, or one that would be
>instantly ruled out by a basic understanding of EFI, as you suggested. 
>And at the risk of repeating myself, if manufacturers always did things
>the best way, there would be no need for forums of this kind.  And since
>the logic of this assertion apparently wasn't clear the first time I said
>it, I will spell it out.  The fact that there are hundreds or thousands
>of people trying to put together their own EFI projects on mailing lists
>like this one, is pretty telling proof that manufacturers do not always
>do things the best way.  Defense rests.
>
>Otherwise, I will not get into an argument about people asking questions
>that are already covered in basic sources.  The reason people ask such
>questions, is that they are hoping to find out without spending hours
>poring over the basic texts.  It may well be that they will decide they
>want the kind of deep, complete information that such study would yield,
>but in the meantime, it is no crime for them to ask such questions, and
>if a member of the list were irritated by the basic questions, they have
>the reasonable option to ignore the questions, delete the message, get on
>with their own more profound researches.  There is not one knowledgeable
>person in existence, about any subject, who was not once a rookie
>himself, and I would speculate that almost every one of those people at
>one time or another asked a very basic question that is covered in basic
>manuals.  Therefore, it would be hypocritical for any one of those people
>to get up in arms because a rookie asks a rookie question.  To the more
>experienced person, I might well say, answer the question, or ignore it,
>but curb your impatience, because that is, in all likelihood,
>hypocritical.
>
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