Date: Sun, 23 Oct 2005 08:59:33 -0500
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: REQ - Dead Idle Stabilizer Control Unit Donation
In-Reply-To: <6da579340510230212t2dab2733i9850438a8a9db05c@mail.gmail.com>
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John,
Sounds like you have made some progress on this. I hope you continue.
What a blessing it would be if you solve the puzzle and can get an
alternative in place that the members of the Vanagon list can use. Maybe
do as Daryl did with the Digifant Digitool - make units and sell them
AND make the info available on a web site for those do-it-yourself
types. That would be very cool!
Keep up the good work.
Regards,
John Rodgers
88 GL Driver
John Bange wrote:
>
> I've a couple of sharp electronics buds here, and with them, I
> want to
> pursue development of a digital replacement for that little box that
> causes so much trouble. Actually, I will probably be more like a
> sidewalk superintendent than a pioneering engineer. My buds will
> pursue
> this with my direction and encouragement.
>
>
> I took one apart and made a partial rough schematic with the intention
> of doing the same thing. Thing is, it's a really tense array of
> op-amps, capacitors, and resistors-- a wacky analog computer doing a
> job better done digitally. My conclusion is that emulating that crazy
> thing at the component level is doing it the hard way. The best way to
> approach it is to treat it like a "black box": monitor its outputs
> while twiddling its inputs to see what it does. Heck, you can even
> figure most of that out from reading the Bentley. Really, a 25 cent
> PIC microcontroller could easily do what those hand-tuned analog crazy
> boxes do, and do it much simpler. Controlling the idle is a simple
> matter of watching the RPMs and opening the ICV when RPM is too low,
> and closing it when it's too high. The advantage digital
> microcontrollers have is that they can 1) count, and 2) tell time.
> That analog circuit trying to measure RPM without either of those
> capabilities is a masterpiece of "old skool" engineering, but totally
> yesterday's news. Abandon ye the old way and start from scratch. All
> it does besides monitor RPM is watch a couple switches on the AC and
> power steering to push the idle RPM up a notch when needed. I've been
> meaning to build such a thing for months, but I've had a "minor"
> complete engine-transmission-hoses replacement to take care of.
> Another 500 miles and the engine will be broken in and I might be able
> to start work on that again.
>
> Anyway, I have a couple broken ones I got from Frank Condelli for $10
> postage. I'll send you the one I didn't disassemble for $5 postage, if
> you like..
>
> --
> John Bange
> '90 Vanagon
> "We'd tell a monkey how to peel a banana, if he said he was peeling
> one in a Vanagon."
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