Spark plug pic's

[justin ivan]

This might be handled Best by retofitting your Cab with the ECU from a G-60 
powered Corrado. It has knock sensing capabilites as well as ignition and 
fuel curves based on MAP values. I know this isn't the answer you are 
looking for but it might be the easiest/most effective method.
Justin
Turbo 92 Vw Jetta


>From: Stephen Webb <swebb at netlab.uky.edu>
>Reply-To: diy_efi at diy-efi.org
>To: diy_efi at diy-efi.org
>Subject: Re: Spark plug pic's
>Date: Tue, 2 Oct 2001 13:01:47 -0400 (EDT)
>
> > Not all detonation, is audible.  You can run trace, and tip in 
>detonation,
> > and never know it.  Do you know what detonation detection strategy Toyo
> > uses?.
>
>Not sure.  I have a question that I have been trying to research,
>however.  Maybe some people can point me to a good resource.
>
>The basic topic is electronic circuits for knock detection, in particular
>using the Bosch style knock sensor.
>
>My project is an '89 VW Cabriolet + a turbocharger.  It's CIS injection,
>not EFI, so I've been somewhat reluctant to bring it up.  My focus right
>now is on the ignition system, which I suppose isn't strictly EFI, but I
>believe is still "on topic" for the list.  I want to build an ignition
>control circuit for the vehicle.  It was not originally equipped with a
>knock sensor, but I would like to add one.
>
>I would like to build a circuit that does the following:
>1. Ignition timing map based on MAP and engine RPM.
>2. Engine knock detection --> ignition retard.
>3. Electronic boost control, RPM based
>4. Idle air stabilizer valve control
>
>Some of this has changed somewhat because my PIC programmer can't deal
>with some of the higher end PICs (I planned on using built in PWM support
>for the IAS valve, and other features made it easy to do multiple things
>at once)
>
>For now the three issues are:
>1.  Safely/correctly interfacing the micro with the hall sender.
>2.  Safely/correctly interfacing the micro with the [stock] ignition
>control module.
>3.  Correctly detecting knock from the knock sensor.
>
>
>I've read the Blue Bosch FI book, and it mentioned engine knock producing
>some frequency.  I believe the Bosch Motronic book said that it was
>typically in the 5kHz range.  One paper I read said that it varied from
>4-8kHz depending largely on engine bore diameter, and a TI whitepaper
>(making a case for their cool DSP chips) said that simple frequency
>detection wasn't good enough for early and robust knock detection, and
>that their DSP solution was the way to go.  I have built a knock sensor
>circuit very similar to this one:
>http://www.gnttype.org/techarea/projects/knock/circuit.gif
>(I believe the one I built is revised;  I can't find the reference right
>now)
>
>I was able to get the circuit to beep, but it's hard to convince myself
>that it is actually working, properly set up for *my* car, etc.
>
>So, I'd like to learn more about engine knock, and in particular detecting
>it with a "Bosch style" knock sensor.
>
>Thanks
>
>-Steve
>
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