Esgee to Present at SAE World Congress 2019: High-Fidelity Numerical Modeling of Spark Plug Erosion

Esgee to Present at SAE World Congress 2019: High-Fidelity Numerical Modeling of Spark Plug Erosion

Esgee Technologies will present “High-Fidelity Numerical Modeling of Spark Plug Erosion” at the SAE International World Congress Experience 2019, April 9-11, at the Cobo Center in Detroit, Michigan.

Abstract

Spark plug erosion is critical in determining the overall efficiency of a spark ignition engine. Over its lifetime, a spark plug is subject to millions of firings. Each spark event results in material erosion due to several mechanisms such as melting, vaporization, sputtering and oxidation. With electrode wear, the inter-electrode spacing increases and a larger voltage difference is required to initiate the spark. The probability of engine misfires also increases with electrode erosion. Once a critical gap is reached, the energy in the ignition coil is not enough to cause a spark breakdown, and the spark plug must be replaced. Due to the long relevant time scales over which erosion occurs, and the difficulty of analyzing the spark plug environment during operation, determining spark plug lifetime typically requires extensive field testing. A high fidelity commercial thermal plasma solver, VizSpark is used simulate electrode erosion due to spark events. The model preserves key arc physics such as current conservation, conjugate heat transfer, fluid flow and electrode ablation. The solution framework includes the capability of coupling high fidelity arc physics with a dynamically deforming spark-plug electrode. A phenomenological model for electrode erosion based on energy is derived from prior experimental work on single-pulse electrode erosion. The energy-based electrode erode model is validated against experimental results, and 3-D electrode erosion simulations in stationary and cross-flow were performed.

Sample Results

8 m/s Cross-Flow                                                                        Stationary Flow

 

Esgee to Present at SAE World Congress 2019: High-Fidelity Numerical Modeling of Spark Plug Erosion

Esgee to Present at SAE World Congress 2019: Simulation of Spark-Initiated Combustion

Esgee Technologies will present “Simulation of Spark-Initiated Combustion” at the SAE International World Congress Experience 2019, April 9-11, at the Cobo Center in Detroit, Michigan.

Abstract

There has been an increased interest in understanding the initial stages of flame kernel formation in internal combustion engines as it offers a potential way of improving their thermal efficiency. For spark-ignited engines, the dynamics that govern the initial spark and its transition into a flame kernel play an important role in determining the overall engine efficiency. In this regard, this paper presents a computational model developed to simulate a spark discharge formed in a premixed fuel air mixture. Additionally, by simultaneously modeling the reactive fluid dynamics that governs combustion with the electromagnetics that governs the spark, the overall objective of this paper is to consistently simulate spark-initiated combustion in a premixed fuel-air mixture. Two different fuel-oxidizer mixtures are considered in this study, hydrogen-oxygen and methane-oxygen. Key mechanisms via which the spark channel ignites the mixture are identified and studied in detail.

Sample Results

Temperature kernel evolution during spark ignition

Water concentration evolution during spark ignition