Towards Integrated Spark and Combustion Modeling for Engines

Abstract

Combustion and emission performance of internal combustion (IC) engines depend on the ability of the ignition system to provide an ignition kernel that can successfully transition into an early flame kernel. Several key physical phenomena such as flow physics, plasma dynamics, circuit transients, and electromagnetics influence the behavior of the spark. The combustion kinetics decide the eventual transition of the spark into a self-sustaining flame kernel. The goal of this paper is to present a feasibility study involving the integration of a high-fidelity magnetohydrodynamic description of the spark physics with a finite rate chemical kinetics-based combustion model. A future goal of this proposed framework will be to model and validate a coupled ignition and combustion simulation for spark ignited engines. Two separate solvers are used to model spark physics and combustion kinetics respectively, and a coupling strategy is developed to model different aspects of physics occurring at disparate time-scales. This approach provides a physically consistent estimate of the electrical energy distribution within the spark-gap under high cross-flow velocities. When provided with certain favorable in-cylinder conditions, the spark kernel triggers self-sustained combustion.