The correct place for firing to occur is 10-20 degrees ATDC, variances in the flame front speed will cause the ignition event to be at a different BTDC time so the firing occurs in the range listed.
Pre ignition is caused by hot spots in the cylinder, no disputes.
There is a lot of talk about causes of detonation, and it is a vague term.
I stand by my statement that detonation is due to excess fuel, either due to over fueling or poor homogenization, as it is caused when the flame front hits excess unburned fuel. The speed of the flame front varies due to cylinder pressure, AFR and fuel quality. Flame front speed will increase with compression. Fuel and the oxygenation of said fuel varies the flame front speed. I am searching for the AFR effects on the flame speed and welcome discussion.
The sound of detonation and preignition are basically the same, but preignition causes more damage due to the push back on the piston as the crank is moving it up.
Here is a good article on the theory of combustion in a cylinder.
Untitled URL Link
Pre ignition is caused by hot spots in the cylinder, no disputes.
There is a lot of talk about causes of detonation, and it is a vague term.
I stand by my statement that detonation is due to excess fuel, either due to over fueling or poor homogenization, as it is caused when the flame front hits excess unburned fuel. The speed of the flame front varies due to cylinder pressure, AFR and fuel quality. Flame front speed will increase with compression. Fuel and the oxygenation of said fuel varies the flame front speed. I am searching for the AFR effects on the flame speed and welcome discussion.
The sound of detonation and preignition are basically the same, but preignition causes more damage due to the push back on the piston as the crank is moving it up.
Here is a good article on the theory of combustion in a cylinder.
Untitled URL Link