What sort of signal is the knock sensor?

[Don.F.Broadus at ucm.com]

Thanks for the info, I had read on a turbo site that the turbo regals use a
6 KHZ sensor , so when the DR 562 came out to that value
I figured it was a good sign that the test set up was OK.

                                                                       Don 

> -----Original Message-----
> From:	Ward [SMTP:wspoonemore at excite.com]
> Sent:	Wednesday, November 24, 1999 10:53 AM
> To:	gmecm at efi332.eng.ohio-state.edu
> Subject:	Re: RE: What sort of signal is the knock sensor? 
> 
> GM has several differnt freq's, depending on application, and the media,
> they do have a few "dry" sensors. 6.?Khaz is the most populat for V8's.
> The
> internal spring is the resonat element.
> 
> Ward
> 
> On Tue, 23 Nov 1999 16:48:37 -0600, Don.F.Broadus at ucm.com wrote:
> 
> > I 'm using a 1.5 inch threaded pipe (1/4 inch NPT)  I removed the pipe
> and
> > butted the  sensors together. This did not provide enough coupling to
> > trigger the ESC. I don't have any more NPT pipe so  I then filled the
> pipe
> > with ultrasonic coupling fluid to see if the cavity was resonating. 6KHz
> was
> > still the sweet spot although a little quieter now.  I believe each det
> > sensor being a peizo transducer has been tuned like a quartz crystal at
> a
> > certain freq. (6KHZ)  By using two  DR 562 sensors they both are in
> > resonance at 6 KHZ. I need to find more det sensors as I only have one
> of
> > certain types right now. The DR 562 is by far the easiest to find being
> used
> > on V8's , V6's four's carbed and injected. I'm looking for Quad  4
> sensors
> > to test believing that they will be tuned  higher to mask the bucket
> tappets
> > and chain noise.
> >                                                  Don  
> > 
> > > -----Original Message-----
> > > From:	jsg at donet.com [SMTP:jsg at donet.com]
> > > Sent:	Tuesday, November 23, 1999 3:59 PM
> > > To:	gmecm at efi332.eng.ohio-state.edu
> > > Subject:	Re: What sort of signal is the knock sensor? 
> > > 
> > > | By using the output of a HP3324A function generator connected to  DR
> 562
> > > | knock sensor coupled with a 1/4 pipe to another DR 562 knock sensor
> I
> > > was
> > > | able to track the freq. curve of the sensor. The sensor responds to
> > > 
> > > <delete>
> > > 
> > > | with a scope the DR 562 sweet spot was 6KHZ. A loud tone could be
> heard
> > > at
> > > | 6KHZ indicating resonance.  7-10KHZ had good outputs. The voltage
> > > dropped
> > > | off at 12 KHZ . An output was observed up to 50KHZ very small
> amplitude
> > > 4
> > > 
> > > Don, is this a resonance of your test setup or of the sensor? (i.e.,
> > > if you double or halve the length of pipe, does it stay the same?)
> > > 
> > > john gwynne
> 
> 
> 
> 
> 
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