Pilot Institute Practice Test

Detonation is a rapid, explosive combustion of the fuel–air mixture, where the reaction front moves through the mixture so fast that it creates a shock wave. This produces a sudden, violent rise in pressure rather than a smooth, even burn. That destructive, instantaneous nature is what distinguishes detonation from the normal, steady burning process. In contrast, ignition delay refers to a lag before the flame starts, a gradual burn describes a slower, diffusive spread of flame (deflagration), and normal combustion sequence is just the regular, controlled burn.