#self-ignition
- To ignite spontaneously — To catch fire by itself, spontaneously or automatically, under the action of a local increase in temperature, pressure, or due to an internal exothermic chemical reaction, without the direct intervention of an external spark or flame source.
- Auto-ignition — A thermochemical phenomenon or process whereby a fuel mixture, gas, or solid material catches fire spontaneously on its own, as a result of an increase in internal temperature or pressure above a critical value (auto-ignition point) and the accumulation of heat released by oxidation reactions, without the intervention of an external ignition source such as a spark or a flame. It represents the fundamental operating principle of Diesel engines.