"Homer J Simpson" wrote in message
news:_DJJh.41829$lY6.17214@edtnps90...

"Captain Midnight" wrote in message
...

Their is no explosion in a properly operating internal combustion
engine.

Sure there is. But you want it at the correct time in the cycle. Knocking
is
caused by misfiring.


Detonation is all of the fuel burning at once(explosion). A proper flame
path will happen relatively slowly to push the piston(burn). The beginning
of the burn is timed to push the piston when the crank is in the proper
position. How long the burn lasts and it's timing is dependent on engine
design and application. If an explosion was acceptable there'd be no need
for high octane fuel. Apparently you've never seen a piston with a hole in
the crown. It's like the difference of flipping a light switch with your
finger or hitting it with a hammer.

Pinging is hot spots in the combustion chamber causing self ignition at the
wrong time. The extra heat from this can cause detonation though.