Gads Spark attack-decay

[garfield at pilgrimhouse.com]

On Wed, 20 May 1998 12:24:05 -0400, cosmic.ray at juno.com (Raymond C
Drouillard) wrote:

>On Tue, 19 May 1998 23:10:14 -0700 garfield at pilgrimhouse.com writes:

>>Well, me, I think the trick is KNOWING which cylinder is the bad guy. A
>>pretty impossible trick, methinks, overall. Piezo knock pickups are
>>placed on the case not so much nearest the known bad boy, as they are
>>attempting to find a spot that's sorta "equidistant" acoustically, from
>>all the cylinders, so no one cylinder has a louder say in who's
>>knocking.
>
>A modern ECU can tell which cylinder is knocking because it knows when it
>is knocking.  The one that just received the spark is the one that is
>knocking.  It'll then retard that one cylinder.

OH sure, but that's not at all the issue that was being discussed!
Knowing the "bad boy", in this thread that Bruce started, was the idea
of knowing the cylinder that was most PRONE to knocking and monitoring
just that one, up real close and personal.

My response above was saying I don't think it's so easy to know which
one IS the bad boy, not which one IS knocking, yes that's easy to know.
See the difference?

My comment about placement of the knock sensor for "equal say" from each
cylinder wasn't in order to tell WHICH one was knocking, but rather to
make sure the knocks from each cyl were heard equally well by the
sensor.

Gar