The cycle to cycle combustion variability which is observed in spark-ignition engines is often caused by fluctuations of the early flame development. LES can be exploited for a better understanding and mastering of their origins. For that purpose appropriate models taking into account energy deposition, mixture ignition and transition to propagation are necessary requirements. This paper presents first DNS and LES of spark ignition with a real automotive coil and simplified pin-pin electrodes. The electrical circuit characteristics are provided by ISSIM while the energy deposition is modelled by Lagrangian particles. The ignition model is first evaluated in terms of initial spark radius on a pin-pin ignition experiment in pure air performed at CORIA and EM2C laboratories, showing that it pilots the radius of the torus formed by the initial shock wave. DNS of a quiescent lean propane/air mixture are then performed with this ignition system and a two-step mechanism. The impact of the modelled transferred energy during glow phase as well as the initial arc radius on the minimum ignition energy (MIE) are examined and compared to experimental values. Replacing the two-step chemistry by an analytically reduced mechanism leads to similar MIE but shows a different ignition kernel shape. Finally, LES of turbulent ignition using a Lagrangian arc model show a realistic prediction of the arc shape and its important role on the energy transfer location and thus on the flame kernel shape.

在火花点火发动机中观察到的循环燃烧可变性的循环通常是由早期火焰发展的波动引起的。可以利用LES更好地了解和掌握其起源。为此，需要考虑能量沉积，混合气着火和过渡到传播的适当模型。本文介绍了具有真正的汽车线圈和简化的针-销电极的火花点火的第一个DNS和LES。电路特性由ISSIM提供，而能量沉积由拉格朗日粒子建模。首先在CORIA和EM2C实验室进行的纯空气针脚点火实验中，根据初始火花半径评估点火模型，表明它控制了由初始冲击波形成的圆环的半径。然后，使用该点火系统和两步机制执行静态贫丙烷/空气混合物的DNS。检查了发光阶段建模的传递能量以及初始电弧半径对最小点火能量（MIE）的影响，并将其与实验值进行了比较。通过分析简化的机理取代两步化学反应可产生相似的MIE，但显示出不同的点火核形状。最后，使用拉格朗日弧模型的湍流点火LES显示了弧形的真实预测，以及其在能量传递位置以及火焰核形状上的重要作用。检查了发光阶段建模的传递能量以及初始电弧半径对最小点火能量（MIE）的影响，并将其与实验值进行了比较。通过分析简化的机理取代两步化学反应可产生相似的MIE，但显示出不同的点火核形状。最后，使用拉格朗日弧模型的湍流点火LES显示了弧形的真实预测，以及其在能量传递位置以及火焰核形状上的重要作用。检查了发光阶段建模的传递能量以及初始电弧半径对最小点火能量（MIE）的影响，并将其与实验值进行了比较。通过分析简化的机理取代两步化学反应可产生相似的MIE，但显示出不同的点火核形状。最后，使用拉格朗日弧模型的湍流点火LES显示了弧形的真实预测，以及其在能量传递位置以及火焰核形状上的重要作用。