Ideas on stoppin some pingin? (long)

[George Roffe]

Bruce Hearn wrote:

>Preignition is combustion caused by a hot spot acting as an ignition
>source in the cylinder before the spark plug fires.  Knock or detonation
>is uncontrolled combustion after the spark plug has started normal combustion.

Bingo.

Pre-ignition and detonation are often confused.  It's not helped by the
fact that engineers often use terms that are not exactly correct just as a
bit if short-hand.  Taylor even does so in this book that Bruce has
referred to: "The Internal Combustion Engine in Theory and Practice."

Taylor writes: "By detonation* is meant the phenomenon which is recognized
as 'ping,' 'spark knock,' or 'carbon knock' and is familiar to all drivers
of automobiles."

"*The word knock is often used interchangeably with the word
detonation.  The author avoids the word 'knock' in this sense becasue the
same word is often used to designate a mechanical sound due to loose
bearings or pistons.  However, the adjective knock-limited is used later in
thsi chapter because it is more convenient and more widely used than the
equivalent term detonation-limited."

So, even the engineers sometimes use terminology that is misleading.

Detonation is indeed an out of control combustion, basically where the end
gases auto-ignite.

George Roffe
Houston, TX
http://www.nissport.com