Spark plug pic's

[Bruce]

At Incoming there is a doc by Bob R. about using a 747, for ignition only.
If your working with a reluctor type distributor, just follow what he did.

Acoustic sensors are, and for ever will be a poor way to look for
detonation.  If you want to hunt for noises, then just use a K/S, and an
op-amp tied to a comparator.   J+S has a high rent unit that uses a
processor, that some seem to happy with.
Bruce

----- Original Message -----
From: "Stephen Webb" <swebb at netlab.uky.edu>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, October 02, 2001 1:01 PM
Subject: Re: Spark plug pic's


> > 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
>
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org