Knock Sensors

[Trevor Boicey]

Kevin Crain wrote:
> I'd guess "engine sensitive" refers to the ECM a respective knock sensor
> is designed for, with respect to the voltage or resistance it uses to
> communicate knock detection to the ECM.

  I would argue that a knock sensor, being essentially
a microphone, is engine sensitive because the actual
acoustics of a knock depend on the engine construction
and very much on the mounting point of the microphone.

  A ping will sound a certain way on a certain
engine to a microphone in a certain spot. A different
block with a different placement will not.

  Since engines are noisy things, the knock sensor
electronics are tuned to listen for a very specific
sound to pronounce it as "knock". Too much off this,
and it might never trigger, or worse, it might trigger
on noises that are normal for that engine.

-- 
Trevor Boicey
Ottawa, Canada
tboicey at brit.ca
http://www.brit.ca/~tboicey/