Empirical Knock Model for Automatic Engine Calibration

Engine knock is an undesired phenomenon in spark ignited internal combustion engines; such as a gasoline engine running the Otto cycle. Knocking originates from abnormal combustions at timings other than those decided by controlled ignition. Individual abnormal combustions of this type is also referred to as auto-ignition. Knocking is not only a limitation on engine efficiency and thus of environmental concern too but also a destructive force, increasing engine weardown. Current research of interest aim for an automatic engine calibration system. One part of calibration would be to find the knock boundary in engine operating condition space, so that when tuning an engine, it is guaranteed to stay within the boundary. This thesis describes a method to find the knock boundary by the use of an empirical knock model based on the Arrhenius equation, calculations of unburned gasoline air mixture temperatures by a temperature mean value approach and the use and improvement of a model parameter called the K-value