Originally Posted by Billabong
I meant 'engineered to avoid detonation'
Detonation can be caused by either excessive temperature or excessive pressure of the fuel-air charge. Take that for granted - but how can you engineer a motor not to det' if you can't actually detect when you have reached the point of detonation? I mean you can obvioulsy ensure that cylinder head temp's etc are kept within tolerance, but if you cannot detect it, you don't know what the tolerances are....
the new generation bmw engines use piezo-electric sensors to detect engine knock.(
http://ccrma.stanford.edu/CCRMA/Cour...ors/node7.html) - for those that are interesed? they are used because the knock is not audible.by linking them to the engine management system the ignition can be advanced to reach optimum performance.the ignition on the bmw engines is advanced in steps of 3 degrees to a maximum of 21 degrees before TDC.if however knocking is detected the ignition is retarded again and then the advancing process repeats.