Self-inflammation
Combustion in diesel engines

If the mixture of fuel and air is exposed to a gradually increasing temperature, it ignites spontaneously when a threshold temperature is exceeded. This is the self-ignition mechanism. This threshold temperature is called the auto-ignition temperature, often referred to as TAI.

Without going into the intricate details of this complex chemical mechanism, it can be described qualitatively as follows:

• at temperatures even lower than TAI, fuel mixed...