Development of Multi-Zone Phenomenological Model for SI Engine

Phenomenological flame propagation model is critical for predicting performance and emissions of spark ignition (SI) engines. A multi-zone phenomenological model offers better accuracy in predicting the emission trends. Hence, in the present work, a multi-zone phenomenological SI flame combustion model is formulated and validated with engine data from published literature. The formulation includes turbulence, combustion, flame propagation, flame geometry interaction with solid walls, gas-to-wall heat transfer, CO and NO emissions from burnt zones and HC emission from quench layer. A knock model has also been implemented. The key contributions are implementation of k-epsilon turbulence model which takes care of contribution from squish/swirl/combustion, predictive multi-zone flame propagation model and a decisive zoning scheme based on percentage of fuel burnt. Validation has been carried out for three different fuels (Iso-octane, Gasoline and Natural Gas) for engine speeds ranging from 1500-4000 rpm establishing the model capabilities to respond to different fuels and engine speed.