Cycle-To-Cycle Variations: A Chaotic Process?

A simple spark ignition engine cycle model has been used to illustrate the concept that cycle-to-cycle variations are an inherent consequence of non-linear combustion kinetics. Sample calculations show highly chaotic behavior when the burn time occupies an excessive fraction of the cycle time. The results are consistent with the well known fact the the engine designer must strive to shorten the burn time as much as possible to minimize variations.