An improved spark ignition model has been developed and implemented into the KIVA-3V code. In this model, the spark ignition kernel growth is tracked by Lagrangian particle markers. The effects of turbulent flow and spark discharge energy on the kernel growth are considered. After the ignition kernel size exceeds a critical size related to the integral turbulent length scale of the flow, the tu...

Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave Report Title Nanocomposite 8Al ·MoO3 thermite particles were prepared using arrested reactive milling and ignited using two experimental techniques. In spark ignition, a monolayer of powder was placed on a conductive substrate and heated in air by a pulsed electrostatic discharge. In shock ignition, an individual particle was ...

Spark-assisted homogeneous charge compression ignition (HCCI) combustion may be a method to improve the operation of HCCI engines. In the current study, the impact of spark assist on the fundamental properties of ignition and combustion was investigated in a single cylinder, optically-accessible research engine. Early port fuel injection and air preheating were used with indolene fuel in the st...

Ignition and flame stabilisation have been simulated in a turbulent, bluff body stabilised spray flame. A complete first order Conditional Moment Closure (CMC) model for spray combustion is presented, as well as CMC modelling for spark ignition. The new elements of the two phase model formalism and the spark ignition models are illustrated using a one dimensional spray ignition example. It is s...

The spark advance determines the efficiency of spark-ignited (SI) engines by positioning the combustion in relation to the piston motion. Today’s spark-advance controllers are open-loop systems that measure parameters that effect the sparkadvance setting and compensate for their effects. Several parameters influence the best spark-advance setting but it would be too expensive to measure and acc...

We report our results on non-periodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly shape similar to a chaotic attractor ...

Large Eddy Simulation (LES) is used to compute the spark ignition in a turbulent methane jet flowing into air. Full ignition sequences are calculated for a series of ignition locations using a one-step chemical scheme for methane combustion coupled with the thickened flame model. The spark ignition is modeled in the LES as an energy deposition term added to the energy equation. Flame kernel for...

Ignition of an ethylene fueled cavity in a supersonic flow was achieved through the application of two energy deposition techniques: a spark discharge and pulse detonator (PD). High-frequency shadowgraph and chemiluminescence imaging showed that the spark discharge ignition was passive with the ignition kernel and ensuing flame propagation following the cavity flowfield. The PD produced a high-...

Highly boosted spark ignition engines must confront violent forms of pre-ignition limiting the maximal low-end torque. French research institute IFP presents here an innovative tool allowing a better understanding of this phenomenon and a structured reasoning considering all potential causes of this phenomenon. Advanced statistical analyses of the combustion process and direct visualisations in...

We analyze the experimental time series of internal pressure in a four cylinder spark ignition engine. In our experiment, performed for different spark advance angles, apart from the usual cyclic changes of engine pressure we observed additional oscillations. These oscillations are with longer time scales ranging from one to several hundred engine cycles depending on engine working conditions. ...