In order for detonation to be detected, it has to occur. So yes, knock sensors and computer programming will reduce engine knock, however it still occurs.
Also, the computer combats detonation by retarding timing. Pulling timing reduces power and efficiency. That hurts performance and fuel economy. Perhaps by negligible amounts, but it occurs no less.

 

Yes...but where are all the blown engines as a result then??
Low octane in, detonation, knock sensors pick it up, ecu adjusts in real time, timing retards, detonation now not happening.
A Very small amount of stress and wear.
Engines are wearing out from the first time they are turned over.
Detonation causes wear, absoloutely, as compression is igniting the lower octane gas before the spark can, while the pistons are still traveling up they are prematurley getting force to push them back down.
I get it. I understand engines.
My original question was, how can an engine with knock sensors destroy itself from detonation?
As long as it's functioning normally...it can't.

 

if the detonation is from the combustion shockwave you are correct, but if its from hot spots in the cylinder head then the ecu cant do anything about it. Probably not as big a deal now with lower btu ethanol diluted fuels, but a legit concern in the unleaded e-00 fuel days with a 60s era combustion chamber and no egr

 

Read my last sentence: "Perhaps by negligible amounts...". I don't think its good for the motor, but I don't think its causing them to explode either.