Theory: Heat sensors in cylenders

[ViPeR_NiPPleX]

indeed, i doubt the temp difference in combustion chamber vs 1-2" downstream of exhaust side of the head will make a significant differerence in readings.

[Nim]

'cept you can tell what the heat is pre-combustion, so you can detect if you are over boosting. But then a pressure sensor would do that too would it.

[Joshstix]

The way to measure detonation in the chambre, or at least the way the BMW do it in the M5 and a lot of others are looking into, is by monitoring the plasma between the electrodes of the spark plug. Apparently it's accurate, measures individual cylinders and used from idle to redline unlike the noise based detonation sensors.

You can also get pressure sensor rings that go in like a washer under the spark plug which measure how hard the spark plug is being pushed upwards and therefore the pressure in the chambre.

[Grega]

see if you can see the article :

http://autospeed.drive.com.au/cms/A_0700/article.html

it doesn't mention much about it other than heat sensors for exhaust gas temp, however, the zoom article did eloborate somewhat more (which i can't find)

[thechuckster]

The way to measure detonation in the chambre, or at least the way the BMW do it in the M5 and a lot of others are looking into, is by monitoring the plasma between the electrodes of the spark plug. Apparently it's accurate, measures individual

This is called 'Ion sensing' - measuring post-combustion state of engine. Combined with knock sensing it makes some sense.

Saab or Audi (sorry, cant remember) did this a while ago - but the complexity of the system out-weighs the usefulness. If you run wide-band O2 and have a good tune to start with, there's not much extra that ion sensing is going to improve things.

on msefi.com there's a bit of discussion about 'Ion sensing' - but not as a ready-to-impliment project.

cheers,
Charles.