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In spark ignition engines, the mechanism of transferring electrical energy from an ignition system into the mixture in the spark gap is controlled by many aspects. The major parameters of these aspects are inputs of electrical energy, combustion energy release, and heat transfers. Heat caused by combustion energy is transferred to the spark plug, cylinder head, unburned mixture, and others. This study presents the development and validation of a flame kernel initiation and propagation model in SI engines, and most of the aspects described above are considered during the course of the model development. Furthermore, the model also takes into account the strain rate of the initial kernel and residual gas fraction. The model is validated by the engine experiments, which are conducted in a constant volume combustion chamber.

The effect of ignition energy, ignition system and spark plug electrode on initial flame kernel development in a constant volume combustion chamber has been studied. The experiment was done in a quiescent and lean condition. Two different ignition systems are designed and evaluated, and several kinds of spark plugs are also made. The spark time controller is also developed to regulate dwell time and to synchronize ignition time with data acquisition time. The ignition energy is measured at each experimental condition, and the flame propagation is measured by piezoelectric type pressure sensor. The heat release rate and the mass fraction burnt are derived from the combustion pressure. The results show that as the dwell time or the spark plug gap are increased, the ignition energy is increased, which derives higher heat release rate and faster the mass fraction burnt.