[Diy_efi] Peak cylinder pressure timing

[Hugh Keir]

There are a number of patents, some going back over 20 years covering the
use of piezo crystals that use the spark plug ceramic as a piston to
compress the piezo crystal against the top of the spark plug housing and
allow you to read the cylinder pressure.

There do not appear to be any systems in the marketplace that take advantage
of this system for peak cylinder pressure readout.

Optrand and Kistler make some more advanced systems that are US$3000 per
spark plug - hardly suitable for the hobbyist.

Having spoken to a piezo manufacturer, it appears that there are crystals
that will give a good response and should stand the heat found at the top of
the spark plug housing. Does anyone have any thoughts on why this is not
do-able for the timing of peak cylinder pressure.

8000 RPM = 48,000 degrees crank rotation per second which should be readable
to something close to 1 degree with a decent processor clock speed and a
simple bit of averaging, compare it to the crank trigger and display the
figure.

Stands back and waits to be shot down!

Hugh



_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi