I see a number of members using the term "pre-detonation" when referring to pre-igniton or detonation.
Pre-ignition is what happens in an internal combustion engine when fuel is ignited by a hot spot prior to the desired ignition point, resulting in higher than normal combustion pressures.
Detonation in an internal combustion engine is when the fuel explodes rather than burns. The technical definition of an an explosion is when the burn front exceeds the speed of sound. The sound you hear when an engine detonates is the "sonic boom" generated by the supersonic flame front. This also results in extremely high combustion pressures.
Pre-detonation is what happens in an atomic weapon if the sub-critical fuel masses are exposed to stray neutrons and undergo spontaneous fission, destroying the fuel before it can be taken super-critical. Needles to say, but I'm going to say it anyway, this is not what is happening in your engine!
Ed
Pre-ignition is what happens in an internal combustion engine when fuel is ignited by a hot spot prior to the desired ignition point, resulting in higher than normal combustion pressures.
Detonation in an internal combustion engine is when the fuel explodes rather than burns. The technical definition of an an explosion is when the burn front exceeds the speed of sound. The sound you hear when an engine detonates is the "sonic boom" generated by the supersonic flame front. This also results in extremely high combustion pressures.
Pre-detonation is what happens in an atomic weapon if the sub-critical fuel masses are exposed to stray neutrons and undergo spontaneous fission, destroying the fuel before it can be taken super-critical. Needles to say, but I'm going to say it anyway, this is not what is happening in your engine!
Ed