Engine knock = premature ignition

thexav

Pro Tuner
Staff member
Points
407
Car
2002 Clio 172
Is engine knock the same thing as premature ignition? Is this also referred to as pinking or pinging?
 
Engine knock is not the same as premature ignition but it is also known as pinking, pinging and detonation.

Pre ignition is where the air/fuel mixture ignites before the spark fires where as engine knock is where the air/fuel mixture ignites correctly by spark but a pocket of air/fuel mixture explodes outside the normal combustion front.

Correct me if im wrong someone :D.
 
Last edited:
I dunno, this is what we were taught at college and that it was a very known misconception that they were the same.
 
If there's too much ignition advance that too can cause knock or pinking. Just that this time it is the ignition timing which is too advanced or the fuel RON rating is too low.

Modern engines use knock sensors so knocking caused by over advance is quickly fixed by the ECU, which retards the ignition timing in response to signals from the knock sensor. Most do this on a cylinder by cylinder basis using one sensor per cylinder bank. Obviously the ECU knows which cylinder due to fire, thus identify the offending cylinder. A lean air:fuel ratio can also cause premature ignition.

For efficiency it's always best for the ignition to be advanced as far as possible, right up until the point that it's on the verge of knocking.
 

Similar threads


Please watch this on my YouTube channel & Subscribe.


Back
Top