Detonation sensors

[David Piper]

At 10:00 AM 3/4/97 -0600, you wrote:
>Can anyone explain the operation of the detonation sensors used to 
>automatically retard spark.

The sensor is a peizoelectric quartz crystal with a resonance near 5kHz
which filters out extraneous noise and allows the high frequency pinging
vibration to be preferentially detected.

The electronics have variable delay lines which index off the primary
ignition trigger signal and apply time delays proportional to the duration
of incidence of the peizo detector signal.  As the signal abates, the
original timing is restored.  Delays up to 20 crank degrees are provided,
but 5 to 10 degrees is usually adequate.



TurboDave  dpiper at one.net  West Chester, Ohio
IZCC # 173
'77 280Z Custom Turbo
Less Maintenance, More Performance.